Article

Pinnington HC, Dawson B. The energy cost of running on grass compared to soft dry beach sand. J Sci Med Sport.4(4):416-30

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

This study compared the energy cost (EC) (J x kg(-1) x m(-1)) of running on grass and soft dry beach sand. Seven male and 5 female recreational runners performed steady state running trials on grass in shoes at 8, 11 and 14 km x h(-1). Steady state sand runs, both barefoot and in shoes, were also attempted at 8 km x h(-1) and approximately 11 km x h(-1). One additional female attempted the grass and sand runs at 8 km x h(-1) only. Net total EC was determined from net aerobic EC (steady state VO2, VCO2 and RER) and net anaerobic EC (net lactate accumulation). When comparing the surface effects (grass, sand bare foot and sand in shoes) of running at 8 km x h(-1) (133.3 m x min(-1)) in 9 subjects who most accurately maintained that speed (133.3 +/- 2.2 m x min(-1)), no differences (P>0.05) existed between the net aerobic, anaerobic and total EC of sand running barefoot or in shoes, but these measures were all significantly greater (P<0.05) than the corresponding values when running on grass. Similarly, when all running speed trials (n = 87) performed by all subjects (n = 13) for each surface condition were combined for analysis, the sand bare foot and sand in shoes values for net aerobic EC, net anaerobic EC and net total EC were significantly greater (P<0.001) than the grass running measures, but not significantly different (P>0.05) from each other. Expressed as ratios of sand to grass running EC coefficients, the sand running barefoot and sand in shoes running trials at 8 km x h(-1) revealed values of 1.6 and 1.5 for net aerobic EC, 3.7 and 2.7 for net anaerobic EC and 1.6 and 1.5 for net total EC respectively. For all running speeds combined, these coefficients were 1.5 and 1.4 for net aerobic EC, 2.5 and 2.3 for net anaerobic EC and 1.5 and 1.5 for net total EC for sand running barefoot and in shoes respectively. Sand running may provide a low impact, but high EC training stimulus.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... foot sinking depth), impact how they walk across the surface to maintain manoeuvrability, grip and stability (Holowka et al., 2022;Peyré-Tartaruga and Coertjens, 2018). Previous studies have found that humans incur a much greater metabolic cost of locomotion when walking or running on natural, compliant substrates such as grass (Davies and Mackinnon, 2006;Pinnington and Dawson, 2001), snow (Pandolf et al., 1976) and sand (Davies and Mackinnon, 2006;Lejeune et al., 1998;Zamparo et al., 1992) compared with solid surfaces. The term 'compliant' has been used broadly within the field (Holowka et al., 2022;Kerdok et al., 2002;Lejeune et al., 1998;Pinnington and Dawson, 2001;Soule and Goldman, 1972;Zamparo et al., 1992) to refer to any substrate that has non-negligible deformation (elastic or plastic) under loads typically generated during human locomotion. ...
... Previous studies have found that humans incur a much greater metabolic cost of locomotion when walking or running on natural, compliant substrates such as grass (Davies and Mackinnon, 2006;Pinnington and Dawson, 2001), snow (Pandolf et al., 1976) and sand (Davies and Mackinnon, 2006;Lejeune et al., 1998;Zamparo et al., 1992) compared with solid surfaces. The term 'compliant' has been used broadly within the field (Holowka et al., 2022;Kerdok et al., 2002;Lejeune et al., 1998;Pinnington and Dawson, 2001;Soule and Goldman, 1972;Zamparo et al., 1992) to refer to any substrate that has non-negligible deformation (elastic or plastic) under loads typically generated during human locomotion. However, the reported increases in energy expenditure vary not only between different types of compliant substrate but also between different studies using the same substrate type. ...
... A variety of different, and sometimes contradictory, reasons have been invoked to explain these increased energetic costs. Pinnington and Dawson (2001) proposed that the differences in energetic costs between studies were likely due to variations in sand properties and/or methodology. Zamparo et al. (1992) proposed that the increase in energetic costs on sand could be attributed to a reduced recovery of potential and kinetic energy at each stride, based on calculations by Cavagna et al. (1976) which modelled the body as a simple inverted pendulum. ...
Article
Full-text available
Our current understanding of human gait is mostly based on studies using hard, level surfaces in a laboratory environment. However, humans navigate a wide range of different substrates every day, which incur varied demands on stability and efficiency. Several studies have shown that when walking on natural compliant substrates there is an increase in energy expenditure. However, these studies report variable changes to other aspects of gait such as muscle activity. Discrepancies between studies exist even within substrate types (e.g. sand), which suggests that relatively ‘fine-scale’ differences in substrate properties exert quantifiable influences on gait mechanics. In this study, we compare human walking mechanics on a range of sand substrates that vary in overall foot sinking depth. We demonstrate that variation in the overall sinking depth in sand is associated with statistically significant changes in joint angles and spatiotemporal variables in human walking but exerts relatively little influence on pendular energy recovery and muscle activations. Significant correlated changes between gait metrics are frequently recovered, suggesting a degree of coupled or mechanistic interaction in their variation within and across substrates. However, only walking speed (and its associated spatiotemporal variables) correlate frequently with absolute foot sinkage depth within individual sand substrates, but not across them. This suggests a causative relationship between walking speed and foot sinkage depth within individual sand substates is not coupled with systematic changes in joint kinematics and muscle activity in the same way as is observed across sand substrates.
... Off-road running exposes the body to unfamiliar and often irregular stresses. Previous studies documented that running on natural surfaces requires greater metabolic energy expenditure than running on smooth hard surfaces [9][10][11][12]. ...
... The transversally inclined surface treadmill can represent a novel way of training that simulates variable terrain when outdoor-specific training is not a feasible option. Previous studies demonstrated how cardiopulmonary responses vary on "irregular surfaces" in the form of modified treadmills and natural surfaces [12,25,32,33]. Changes in mechanical work performed by muscles during walking and running on uneven terrain may explain nearly half of the increase in metabolic cost from the transition from smooth to ...
... The transversally inclined surface treadmill can represent a novel way of training that simulates variable terrain when outdoor-specific training is not a feasible option. Previous studies demonstrated how cardiopulmonary responses vary on "irregular surfaces" in the form of modified treadmills and natural surfaces [12,25,32,33]. Changes in mechanical work performed by muscles during walking and running on uneven terrain may explain nearly half of the increase in metabolic cost from the transition from smooth to uneven surfaces [25,33]. ...
Article
Full-text available
This paper compares cardiopulmonary and neuromuscular parameters across three running aerobic speeds in two conditions that differed from a treadmill’s movement: flat condition (FC) and unpredictable roll variations similar to mountain trail running (URV). Twenty well-trained male runners (age 33 ± 8 years, body mass 70.3 ± 6.4 kg, height 1.77 ± 0.06 m, V˙O2max 63.8 ± 7.2 mL·kg−1·min−1) voluntarily participated in the study. Laboratory sessions consisted of a cardiopulmonary incremental ramp test (IRT) and two experimental protocols. Cardiopulmonary parameters, plasma lactate (BLa−), cadence, ground contact time (GT) and RPE values were assessed. We also recorded surface electromyographic (sEMG) signals from eight lower limb muscles, and we calculated, from the sEMG envelope, the amplitude and width of peak muscle activation for each step. Cardiopulmonary parameters were not significantly different between conditions (V˙O2: p = 0.104; BLa−: p = 0.214; HR: p = 0.788). The amplitude (p = 0.271) and width (p = 0.057) of sEMG activation peaks did not change between conditions. The variability of sEMG was significantly affected by conditions; indeed, the coefficient of variation in peak amplitude (p = 0.003) and peak width (p < 0.001) was higher in URV than in FC. Since the specific physical demands of running can differ between surfaces, coaches should resort to the use of non-traditional surfaces, emphasizing specific surface-related motor tasks that are normally observed in natural running environments. Seeing that the variability of muscle activations was affected, further studies are required to better understand the physiological effects induced by systematic surface-specific training and to define how variable-surface activities help injury prevention.
... However, our current understanding of animal gait and energetics is dominated by studies on hard, level surfaces in laboratories, which do not reflect most naturally occurring terrains. Recent work on humans has shown that locomotion on complex substrates like loose rock surfaces [1], ballast [2], uneven [3,4] and compliant [5][6][7][8][9][10] terrains is typically associated with an increase in energy expenditure relative to uniform, non-deforming substrates. Indeed, variations in the compliance or stiffness of footwear has also been shown to systematically affect locomotor costs [11,12]. ...
... Indeed, variations in the compliance or stiffness of footwear has also been shown to systematically affect locomotor costs [11,12]. The term 'compliant' has been used broadly within the field [4][5][6][7][8][9] to refer to any substrate that has non-negligible deformation under loads typically generated during human locomotion. A substantial body of literature has sought to understand elevated energetic costs on compliant substrates like sand, mud and snow [5][6][7]13], but at present there remains little consensus about the primary mechanistic causes. ...
... Pinnington & Dawson [8] suggested a potential increase in muscle co-activation and an increase in foot contact time on compliant substrates may lead to increased oxygen consumption due to a reduction in elastic energy storage and recovery, and ultimately a decrease in muscle-tendon efficiency. These authors noted that foot slippage may also play a role, as postulated by Zamparo et al. [6]. ...
Article
Full-text available
Walking on compliant substrates requires more energy than walking on hard substrates but the biomechanical factors that contribute to this increase are debated. Previous studies suggest various causative mechanical factors, including disruption to pendular energy recovery, increased muscle work, decreased muscle efficiency and increased gait variability. We test each of these hypotheses simultaneously by collecting a large kinematic and kinetic dataset of human walking on foams of differing thickness. This allowed us to systematically characterize changes in gait with substrate compliance, and, by combining data with mechanical substrate testing, drive the very first subject-specific computer simulations of human locomotion on compliant substrates to estimate the internal kinetic demands on the musculoskeletal system. Negative changes to pendular energy exchange or ankle mechanics are not supported by our analyses. Instead we find that the mechanistic causes of increased energetic costs on compliant substrates are more complex than captured by any single previous hypothesis. We present a model in which elevated activity and mechanical work by muscles crossing the hip and knee are required to support the changes in joint (greater excursion and maximum flexion) and spatio-temporal kinematics (longer stride lengths, stride times and stance times, and duty factors) on compliant substrates.
... Sand surfaces may provide a training stimulus that elicits a higher energetic cost with less ground reaction force compared to the more traditional training surfaces, such as synthetic fabrics or grass [10]. The high shock absorption capacity of sand may decrease the impact forces experienced during high-intensity activities, which may lead to a reduction in muscle lesions and pain and improve recovery time between sessions [10,11]. Considering these differences, recent evidence supports the use of sand as a training means to improve the performance of team sports athletes [12]. ...
... A study by Binnie et al. [7] investigated the effect of sand surfaces during a training session comprising running at different speeds for a longer period (60 min). Specifically, these studies compared the use of sand and grass surfaces during training sessions [7,9,11,15]. For a session functioning with standardised intervals, the use of sand instead of grass or synthetic surfaces led to a significantly higher average heart rate (sand: 172 bpm; grass: 163 bpm) and blood lactate values (sand: 10.1 mmol ·L −1 , grass: 6.5 mmol · L −1 ) throughout the training session [13,16]. ...
... Considering the training studies carried out thus far, additional research is necessary to determine a whole array of benefits associated with training on the sand. Namely, the main characteristic associated with exercising on sand is higher movement energy cost [11,15] and the capacity of reaching higher training intensities during a training session is higher compared to training on a traditional surface [45,46]. Consequently, additional research is required to investigate the implications of training on the sand, with a focus on aerobic and muscular adaptations and the causes that trigger changes in the concentration of EPO and haemoglobin. ...
Article
Full-text available
Altitude training increases haemoglobin, erythropoietin values among athletes, but may have negative physiological consequences. An alternative, although less explored, that has the potential to positively influence performance while avoiding some of the negative physiological consequences of hypoxia is sand training. Ten endurance-trained athletes (age: 20.8 ± 1.4, body mass: 57.7 ± 8.2 kg, stature: 176 ± 6 cm; 5000 m 14:55.00 ±0:30 min) performed three 21-day training camps at different locations: at a high altitude (HIGH), at the sea-level (CTRL), at the sea-level on the sand (SAND). Differences in erythropoietin (EPO) and haemoglobin (Hb) concentration, body weight, VO2max and maximal aerobic velocity (VMA) before and after each training cycle were compared. Data analysis has indicated that training during HIGH elicited a greater increase in VO2max (2.4 ± 0.2%; p = 0.005 and 1.0 ± 0.2%; p < 0.001) and VMA (2.4 ± 0.2%, p < 0.001 and 1.2 ± 0.2%; p = 0.001) compared with CTRL and SAND. While increases in VO2max and VMA following SAND were greater (1.3 ± 0.1%; p < 0.001 and 1.2 ± 0.1%; p < 0.001) than those observed after CTRL. Moreover, EPO increased to a greater extent following HIGH (25.3 ± 2.7%) compared with SAND (11.7 ± 1.6%, p = 0.008) and CTRL (0.1 ± 0.3%, p < 0.001) with a greater increase (p < 0.01) following SAND compared with CTRL. Furthermore, HIGH and SAND elicited a greater increase (4.9 ± 0.9%; p = 0.001 and 3.3 ± 1.1%; p = 0.035) in Hb compared with CTRL. There was no difference in Hb changes observed between HIGH and SAND (p = 1.0). Finally, athletes lost 2.1 ± 0.4% (p = 0.001) more weight following HIGH vs. CTRL, while there were no differences in weight changes between HIGH vs. SAND (p = 0.742) and SAND vs. CTRL (p = 0.719). High-altitude training and sea-level training on sand resulted in significant improvements in EPO, Hb, VMA, and VO2max that exceeded changes in such parameters following traditional sea-level training. While high-altitude training elicited greater relative increases in EPO, VMA, and VO2max, sand training resulted in comparable increases in Hb and may prevent hypoxia-induced weight loss. Citation: Man, M.C.; Ganera, C.; Bărbule, G.D.; Krzysztofik, M.; Panaet, A.E.; Cucui, A.I.; Tohănean, I.; Alexe, D.I. The Modifications of Haemoglobin, Erythropoietin Values and Running Performance While Training at Mountain vs. Hilltop vs. Seaside. Int. J. Environ. Res. Public Health 2021, 18, 9486. https://
... First, the original algorithms were based on running on a compact terrain (e.g., a treadmill; [16,17]). Second, running on a grass surface and also the appropriateness of the footwear has been shown to elevate C r by~30% and impact kinematics, respectively, when compared to running on a dense terrain [18]. Third, fitness levels have been shown to influence C r as running economy can easily be improved through training [19,20], with research on professional soccer players showing a higher C r by 14% from pre-season compared to in-season [21]. ...
... Osgnach et al. [13] based their MP equation on the research conducted by Minetti et al. [17] and added the Pinnington and Dawson [18] correction, which consists of a multiplication term of 1.29 (KT = 1.29) to reflect the difference between running on a treadmill and grass. However, the incorporation of this multiplication term may impact the accurate determination of the C of soccer-specific activities as the KT was developed in recreational runners, which may not represent a suitable kinematic model of running in elite soccer [18]. ...
... Osgnach et al. [13] based their MP equation on the research conducted by Minetti et al. [17] and added the Pinnington and Dawson [18] correction, which consists of a multiplication term of 1.29 (KT = 1.29) to reflect the difference between running on a treadmill and grass. However, the incorporation of this multiplication term may impact the accurate determination of the C of soccer-specific activities as the KT was developed in recreational runners, which may not represent a suitable kinematic model of running in elite soccer [18]. Therefore, the multiplication coefficient needs to be revisited to ensure a better and more accurate representation of the metabolic constant expressed in elite soccer players on soccer-specific activities [22]. ...
Article
Full-text available
The aim of this study was to update the metabolic power (MP) algorithm (PVO2), W·kg−1) related to the kinematics data (PGPS, W·kg−1) in a soccer-specific performance model. For this aim, seventeen professional (Series A-League) male soccer players (VO2max 55.7 ± 3.4 mL∙min−1∙kg−1) performed a 6-min run at 10.29 km·h−1 to determine linear-running energy cost (Cr). On a separate day, thirteen also performed an 8-min soccer-specific intermittent exercise protocol. For both procedures, a portable Cosmed K4b2 gas-analyzer and GPS (10 Hz) was used to assess the energy cost above resting (C). From this aim, the MP was estimated through a newly derived C equation (PGPSn) and compared with both the usually commonly used (PGPSo) equation and direct measurement (PV ̇O2). Both PGPSn and PGPSo correlated with PV ̇O2) (r = 0.66, p < 0.05). Estimates of fixed bias were negligible (PGPSn = −0.80 W∙kg−1 and PGPSo = −1.59 W∙kg−1), and the bounds of the 95% CIs show that they were not statistically significant from 0. Proportional bias estimates were negligible (absolute differences from one being 0.03 W∙kg−1 for PGPSn and 0.01 W∙kg−1 for PGPSo) and not statistically significant as both 95% CIs span 1. All variables were distributed around the line of unity and resulted in an under- or overestimation of PGPSn, while PGPSo routinely underestimated MP across ranges. Repeated-measures ANOVA showed differences over MP conditions (F1,38 = 16.929 and p < 0.001). Following Bonferroni post hoc test showed significant differences regarding the MP between PGPSo and PV ̇O2/PGPSn (p < 0.001) were established, while no differences were found between PVO2 and PGPSn (p = 0.853). The new approach showed it can help the coaches and the soccer trainers to better monitor external training load during the training seasons.
... Sandy surface causes less post exercise myalgia than hard ground surface [16,17]. It consumes more exercise energy of players [12,13,[18][19][20]. Thus, exercises on sands are recommended to improve both aerobic-and anaerobic exercises [13,18]. ...
... It consumes more exercise energy of players [12,13,[18][19][20]. Thus, exercises on sands are recommended to improve both aerobic-and anaerobic exercises [13,18]. It is used in rehabilitation for neuromuscular injuries [10,12]. ...
... Additionally, domestic and overseas prior studies on such topics have reported various effects of exercises on unstable ground surfaces. However, these studies have focused on limited elements to improve athletic ability of athletes [11][12][13]18,20,27]. Studies focusing on exercises on sands for ordinary people are few. ...
Article
Full-text available
PURPOSE The primary objective of this study was to investigate the effect of sand surface exercise compare with general surface exercise on balance capability, extremity muscle activity, and inflammatory markers in older women. METHODS A total of 40 subjects aged over 65 years were enrolled for this study. They were assigned into two groups (20 subjects in each group): 1) exercise on sand (SG); and 2) exercises on general ground (HG). RESULTS There was no interaction effect between group and time on body composition and blood pressure. There were significant difference in overall, anterior/posterior, medial/lateral between the SG and HG. And changes in proprioceptive sensation were significantly different between the two groups. Knee extension was also significantly higher in the HG than in the sand group. There were significant difference in the tibialis anterior, the gastrocnemius, and biceps femoris between the SG and HG. There were significant increases in respective muscle activities after exercises in SG. After the exercise program, there was a significant difference between times in C-reactive protein (CRP). There were significant difference in rheumatoid arthritis factor (RA factor) factor between the SG and HG. Also, SG resulted in a greater reduction in RA factor than the HG. CONCLUSIONS Our results suggest that sand exercise program can produce benefits with regard to balancing capacity functional improvement, reduction of inflammatory markers, and prevention of proprioceptive sensation in the older women, thus contributing to a better quality of life.
... Many studies have applied various surfaces, e.g., irregular and unstable surfaces, to challenge several aspects relating to mobility such as balance ability, muscular activity, and energy expenditure of their participants [6][7][8][9][10][11]. However, the data were confined to able-bodied young adults, older individuals, and people with amputees, or patients with diabetes mellitus [7,11,12]. ...
... The findings reflect the challenging effects of the surfaces on the walking abilities of the participants. Walking on the artificial grass surface attributed information through the leaf length that facilitated the participants to increase flexor strategy and toe clearance during a swing phase [6,12]. Previous studies reported that the soft nature of grass also reduces the ground reaction force, thereby enhancing muscle activity and reducing the acceleration force during a swing period [6,24]. ...
... Walking on the artificial grass surface attributed information through the leaf length that facilitated the participants to increase flexor strategy and toe clearance during a swing phase [6,12]. Previous studies reported that the soft nature of grass also reduces the ground reaction force, thereby enhancing muscle activity and reducing the acceleration force during a swing period [6,24]. Thus, the participants decreased their stride length, cadence, and walking speed while walking on a grass surface as compared with these parameters on a hard surface (Figs. 2 and 3). ...
Article
Full-text available
Study design: A cross-sectional study. Objective: To assess the influence of various surfaces on the gait characteristics of ambulatory participants with incomplete spinal cord injury (SCI) as compared to data from able-bodied participants. Setting: A tertiary rehabilitation center and communities. Methods: Seventy participants (35 ambulatory individuals with incomplete SCI and 35 able-bodied individuals with gender- and age-matched) were assessed for their spatiotemporal gait variables while walking over a 10-m walkway of different surfaces (including hard, artificial grass, soft, and pebble surfaces) at a self-selected and fastest speed. The findings were analyzed using the method of manual digitization. The data among the surfaces were compared using Kruskal-Wallis test and Mann-Whitney U test, with a level of statistical significance at P < 0.05. Results: Participants with incomplete SCI could safely walk over every surface without any adverse events. Their average stride length, cadence, and walking speed, but not percent step length symmetry, were significantly decreased while walking on the artificial grass, soft, and particularly pebble surfaces as compared to those found on a hard surface. These changes were found particularly in those with SCI, resulting in a walking speed decreased from 0.11 to 0.35 m/s, whereas the reduction of walking speed of able-bodied participants ranged from 0.04 to 0.20 m/s. Conclusions: The spatiotemporal characteristics of ambulatory participants with SCI were dramatically affected by the surfaces as compared to the data found in able-bodied participants. The findings have potential clinical implications for the incorporation of various surfaces to promote the functional outcomes and safety for ambulatory individuals with SCI.
... The sand imposes a greater load on players' movements and jumps due to its irregular and deformable surface [4,13]. Therefore, the neuromuscular demands and energetic cost of sand are higher at a similar running speed in comparison to less resistant surfaces, such as grass and cement [12,[14][15][16]. Actually, even if court handball players generally have a higher body contact rate, such as pushes or hits, beach handball players are required to perform displacements on an unstable sand surface, increasing the physical demands during training and competition [17]. ...
... These factors have a negative influence on performance (i.e., sprinting), since they produce a decrease in the peak force and in the duration of the force output [21]. This leads to a decrease in the acceleration due to the difficulty the foot has in propelling forward during the pushing phase (i.e., lowerhorizontal force component) [15,16]. Despite the relevance of sand sprinting performance to BH, prior research has not explored the sprint mechanical FVP profile of BH female players on different surfaces. ...
Article
Full-text available
Beach handball (BH) is characterized by high-intensity actions, such as accelerations and short rest times, in combination with long periods of low-intensity activity during a match. The purpose of this study was to establish a comparative analysis between the effect of a hard surface vs. sandy surface on the properties of the sprint Force–Velocity–Power Profile (FVP) of female beach handball top-level players. Fourteen female BH players participated in this research. A cross-sectional investigation was performed in order to evaluate the determining variables of the FVP profile for different surfaces. After a specific warm-up, two maximal 20–30 m sprints (4 min resting between trials) were performed in two conditions (hard surface and sand) within 10 min. The female BH players showed higher mean values for all the FVP profile variables (p < 0.001) on the hard surface compared to sand, in addition to lower values for the 5 m (ES = 2.29 to 3.89) and 20 m sprinting times (ES = 2.39 to 3.99) (p < 0.001). However, the decrease in the ratio of force over acceleration was not discriminant between the surfaces. Positive correlations were found for the speed variables (0.691–0.807, p < 0.01), as well as the Pmax (0.520, p = 0.035), between the surfaces. A prior knowledge of the FVP profile for hard–sandy surfaces could offer an important reference value about the sprint properties of this population, and be useful for evaluating the efficiency, as well as the effect on the sprint and gaming performance, of specifically oriented training programs based on those reference values.
... Sand surfaces (SAND) are a demanding exercise surface. Research evidence suggests that a higher energy cost is required for running [1][2][3][4][5], walking [6,7], sprinting [8,9] and jumping [10][11][12] on SAND compared to rigid (RIGID) surfaces. Despite the higher energy cost, training on SAND causes positive adaptations in key strength and conditioning factors such as aerobic endurance, concentric strength of the leg extensor muscles and agility in a variety of sport disciplines [13]. ...
... Additionally, SAND comprises a demanding surface to execute explosive movements since its surface is characterized by larger friction compared to other sport surfaces [33]. The interaction with SAND during exercise utilizing the SSC is suggested to absorb large amounts of energy [3,10,11,29,33,34]. In addition, jumping on SAND utilizing the SSC is proposed to lead to lower re-use of the stored elastic energy [10]. ...
Article
Full-text available
Plyometric training on sand is suggested to result in advanced performance in vertical jumping. However, limited information exists concerning the biomechanics of drop jumps (DJ) on sand. The purpose of the study was to compare the biomechanical parameters of DJs executed on rigid (RIGID) and sand (SAND) surface. Sixteen high level male beach-volleyball players executed DJ from 40 cm on RIGID and SAND. Force-and video-recordings were analyzed to extract the kinetic and kinematic parameters of the DJ. Results of paired-samples t-tests revealed that DJ on SAND had significantly (p < 0.05) lower jumping height, peak vertical ground reaction force, power, peak leg stiffness and peak ankle flexion angular velocity than RIGID. In addition, DJ on SAND was characterized by significantly (p < 0.05) larger rate of force development and knee joint flexion in the downward phase. No differences (p > 0.05) were observed for the temporal parameters. The compliance of SAND decreases the efficiency of the mechanisms involved in the optimization of DJ performance. Nevertheless, SAND comprises an exercise surface with less loading during the eccentric phase of the DJ, thus it can be considered as a surface that can offer injury prevention under demands for large energy expenditure.
... 14 there is an increase in concentric muscle activity in propulsive muscles and consequently a higher energy cost of soft sand running compared to firm surfaces. 43,44 This was not extensively investigated in horses, but it was demonstrated that the overall loading of the forelimb in horses is reduced and more progressive on deep sand compared to firm sand but the propulsive muscular effort is increased as the consequence of the poor damping effect of the deep sand. 44,45 From these data, it is possible that dry sand increased the energy cost of locomotion, probably resulting in a higher heart rate at a lower speed, allowing training of the cardiorespiratory system without reaching the maximal speed when horses compete on the wet sand. ...
... In Thoroughbreds, synthetic surfaces were demonstrated acting as a risk factor for the development of pelvic and tibial stress fractures and the type of training or competition surface are recognised as having a role in stress fracture.[39][40][41] Some studies in human sports medicine and Standardbred horses demonstrated that training in soft, compliant surfaces like deep sand, results in decreased impact forces and loading rate but muscle activation is emphasised.[42][43][44][45] In human sports medicine, ...
Article
Full-text available
Background Bone stress injuries and fatigue fractures of the pelvis are reported in only a small number of endurance horses. Objectives To describe bone stress injuries and fatigue fracture of the pelvis in endurance horses trained and competing on the deep sand surfaces. Study design Retrospective case series. Methods Medical records of horses used for endurance and diagnosed with bone stress injuries and/or fatigue fractures of the pelvis by ultrasound were reviewed. The bone stress injuries and fatigue fractures were classified as affecting the iliac wing, the iliac shaft, the tuber ischiadicum, the rest of the ischium or the pubis and subdivided into four fracture configurations: isolated iliac fracture, isolated fracture of the floor of the pelvis, isolated tuber ischiadicum fracture and multiple fractures. Descriptive statistics were performed overall and on fracture configurations for age, sex, breed, level of activity, affected limbs, previous injuries, development of the injury, seasons in the UAE, physical and dynamic findings and outcome. For each fracture configuration and the outcome, multivariable logistic regression models were developed after univariable logistic regression and collinearity analyses. Significance was set at P ≤ .05. Results Sixty endurance horses were included; 48% (95% CI: 36%‐61%) had isolated iliac fracture, 17% (7%‐26%) isolated fracture of the floor of the pelvis, 15% (6%‐24%) isolated tuber ischiadicum fracture and 20% (10%‐30%) had multiple fractures. Breed (OR, 4.42; 95%CI, 1.02‐19.57) was significantly associated with isolated iliac fracture and asymmetry of bone landmarks (OR, 7.42; 95% CI, 1.47‐37.45) with isolated tuber ischiadicum fracture. Degree of lameness (OR, 3.08; 95% CI, 1.07‐8.9) and trotting on three tracks (OR, 8.62; 95% CI, 1.43‐51.9) were significantly associated with the diagnosis of isolated fracture of the floor of the pelvis. Main limitations Data acquired in a single country. Conclusions Bone stress injuries and fatigue fractures of the pelvis can affect endurance horses trained and competing on deep sand. Isolated bone stress injuries and/or fatigue fractures of the ileum were the commonest followed by multiple pelvic bones involvement. The presence of lameness and trotting on three tracks suggest the presence of bone stress injuries and/or fatigue fractures of the floor of the pelvis; asymmetry of bony landmarks is more commonly detected in horses with bone stress injuries and/or fatigue fractures of the tuber ischiadicum.
... However, one study reported intra-participant variation in inertial sensor monitored running gait profiles across soft sand, hard sand and athletics track [7]. Sand surface running can offer higher energy cost and a lower-impact training stimulus [8][9][10][11], making it a suitable surface for runners recovering from This article is a part of Topical Collection in Sports Engineering on Wearable Sensor Technology in Sports Monitoring, edited by Dr Hugo G Espinosa. knee and hip impact-related injuries such as stress fractures and ligament tears. ...
... However, there was a significant difference in the participant's rate of perceived exertion score across each of the running surfaces (p = 0.0046). This result agrees with the findings of Binnie et al. [8] and Pinnington and Dawson [9], that sand running, in particular soft sand, is more energy demanding. It also demonstrates that the PlayerLoad metric cannot accurately quantify athlete work rate on different surface types. ...
Article
Running surfaces influence energy consumption and gait parameters including swing time and stance time. This paper compares running gait cycle time, swing time and stance time, recorded on an athletics track, soft sand, and hard sand. The training and evaluation of supervised machine learning models for running surface prediction were developed using an ankle-worn inertial sensor. Models were trained using statistical features extracted from six participants using gyroscope-based stride cycles. Six different model types were trained and the performance of each model was evaluated using precision, recall, F1-score, Matthews correlation coefficient, area under the precision-recall curve and accuracy. There was a significant statistical difference in swing time and stance time across the surfaces for all participants (p < 0.05). Athlete-independent models demonstrated acceptable ability to distinguish soft sand from the two harder surfaces (≥ 0.75 mean precision, ≥ 0.90 mean recall, ≥ 0.83 mean F1-score, ≥ 0.98 mean area under the precision-recall curve across all models), but they were poor at differentiating between athletics track and hard sand. The athlete-dependent models demonstrated strong ability to classify all the surfaces (weighted average precision, recall, F1-score, Matthews correlation coefficient, area under the precision recall curve, and overall accuracy ≥ 96%). Support vector machine models were the best in both athlete-independent and athlete-dependent methodologies. Features extracted from an ankle-worn inertial sensor can be used to classify running surface with high performance, when models are trained using features pertinent to each athlete.
... The sample size was previously estimated to induce a meaningful detectable effect size (Cohen's d) of 0.60 between training surfaces with the assumption of a statistical power of 0.90 at an alpha level of 0.05. The effect size used to generate the sample size was derived from previous investigations comparing the physiological responses between training surfaces assuming HR and RPE measures as references (Pinnington and Dawson, 2001b;Binnie et al., 2013a). The calculations were made using a customized computer software (GPOWER Version 3.1.9.2, ...
... These movement pattern changes in association with a higher running cost may explain the observed lower PS T−CAR in the SAND condition (Zamparo et al., 1992;Pinnington and Dawson, 2001a,b;Gaudino et al., 2013). Indeed, previous research showed that SAND demanded significantly higher VO 2 and [La] values than running on GRASS at comparable speeds, thus resulting in a steeper slope in the VO 2 and [La] vs. running speed relationship (Pinnington and Dawson, 2001b). However, possible inferences regarding the energy contribution during the T-CAR should be interpreted with caution, since neither the present nor the previous study of Cetolin et al. (2010) measured VO 2 responses during submaximal T-CAR speeds on SAND surface. ...
Article
Full-text available
This study aimed to examine the acute physiological effect of shuttle-run-based high-intensity intermittent exercise (HIIE) performed at the same relative speed (i. e., 100% PST−CAR) on sand (SAND) and grass (GRASS) in male junior soccer players. Seven Under-23 Brazilian national league (“Série A”) soccer players completed four testing sessions in either SAND or GRASS surface condition. The first two testing sessions consisted of performing a maximal progressive shuttle-run field protocol until volitional exhaustion (Carminatti's test, T-CAR), whereas the third and fourth sessions comprised a HIIE session on each ground surface. The HIIE session consisted of three 5-min bouts [12 s shuttle-run (with a direction change every 6 s)/12 s of passive rest] performed at 100% of T-CAR peak speed (PST−CAR) with 3 min of passive recovery between sets. Measurements of oxygen uptake (VO2), heart rate (HR), blood lactate concentration ([La]), and rating of perceived exertion (RPE) were performed during all conditions. The SAND condition elicited significantly higher %VO2peak (94.58 ± 2.73 vs. 87.45 ± 3.31%, p < 0.001, d = 2.35), %HRpeak (93.89 ± 2.63 vs. 90.31 ± 2.87%, p < 0.001, d = 1.30), RPE (8.00 ± 0.91 vs. 4.95 ± 1.23 a.u., p < 0.001, d = 2.82), and [La] (10.76 ± 2.37 vs. 5.48 ± 1.13 mmol/L, p < 0.010, d = 2.84). This study showed that higher internal workloads are experienced by the players during a single HIIE session performed on a softer surface as SAND, even when the exercise intensity was individualized based on 100%PST−CAR.
... The energy cost of running through long grass on rough terrain is increased because of decreased step lengths, greater hip flexion during swing, and larger vertical displacements of the CM (Creagh and Reilly, 1997). Pinnington and Dawson (2001) found that running on sand had a greater energy cost than running on grass and proposed that this was because of a reduction in elastic energy potentiation, caused partly by an increase in contact time. They also suggested that the increase in energy cost could be because sand's compliant nature requires increased leg stiffness that increases muscle activity to stabilise the lower limb joints (Pinnington and Dawson, 2001). ...
... Pinnington and Dawson (2001) found that running on sand had a greater energy cost than running on grass and proposed that this was because of a reduction in elastic energy potentiation, caused partly by an increase in contact time. They also suggested that the increase in energy cost could be because sand's compliant nature requires increased leg stiffness that increases muscle activity to stabilise the lower limb joints (Pinnington and Dawson, 2001). Although running on such surfaces might reduce performance (e.g., time to complete a particular distance compared with athletics tracks or roads), they can provide a beneficial training stimulus, and can suit some athletes' running styles better than more stable, harder surfaces. ...
Chapter
Full-text available
A knowledge of the biomechanics of running is invaluable when describing an athlete’s technique, explaining how they speed up or slow down, and understanding the external and internal forces that cause their movements. As the outward expression of movement, an athlete’s biomechanics translates their underlying physiological, nutritional and psychological processes into running motion, and those who are biomechanically “better” are often those who can manage this transfer more efficiently and economically while reducing injury risk. This chapter provides a brief review of the important aspects of the running stride and its various components, the effects of different footstrike patterns and fatigue on running technique, and how racing conditions such as wind, hills and underfoot surface affect an athlete’s biomechanics.
... Thus, the participants needed muscular activity and balance control ability to lift their leg from the floor greater than that over a hard and leveled surface. 8,32 The combination of these surfaces posed high demands for the participants with a good walking ability and at a chronic stage of injury both during stance and swing periods. 8,[29][30][31][32] After repetitive practice over these surfaces, the participants demonstrated significant improvement in their functional outcomes as measured using the 10MWT, TUGT, FTSST, and 6MWT at 2 and 4 weeks after training (P<.001) (see table 2). ...
... 8,32 The combination of these surfaces posed high demands for the participants with a good walking ability and at a chronic stage of injury both during stance and swing periods. 8,[29][30][31][32] After repetitive practice over these surfaces, the participants demonstrated significant improvement in their functional outcomes as measured using the 10MWT, TUGT, FTSST, and 6MWT at 2 and 4 weeks after training (P<.001) (see table 2). The 10MWT reflects a walking speed that is a vital determinant of the overall quality of walking, ability to perform daily activities, and community participation in ambulatory individuals with SCI. ...
Article
Objectives: To compare effects of walking training on a walking track with different surfaces (WTDS), including artificial grass, soft, and pebbles, as compared to overground walking training on the functional ability necessary for independence and incidence of falls of ambulatory individuals with spinal cord injury (SCI). Design: A randomized controlled trial (single-blinded design) with 6-month prospective fall data follow-up. Setting: Tertiary rehabilitation centers and several communities. Participants: Independent ambulatory individuals with SCI who walked with or without a walking device (N = 54). Intervention: Participants were randomly arranged into a control group (overground walking training, N = 26) or experimental group (walking training over a WTDS, N = 28) for 30 min/day, 5 days/week over 4 weeks. Main outcome measures: The 10-meter walk test, timed up and go test, five times sit-to-stand test, and 6-minute walk test were repeatedly measured 4 times, including before training, and after 2-week and 4-week, and 6 months. In addition, participants were prospectively monitored for the fall data over 6 months. Results: Participants who walked with an average speed of 0.52 m/s and post-injury time >7 years could safely walk over a WTDS. They demonstrated significant improvement at 2-week and 4-week following experimental training (P<0.001), but not after control training. During 6-month follow-up, participants in the experimental group also had the number of those who fell (n = 5, 18%) fewer than those in the control group (n = 12, 46%). Conclusions: Being at a chronic SCI with ability of independent walking, participants needed a challenging task to promote their functional outcomes and minimize fall risk. The findings suggest the use of various surfaces as an alternative rehabilitation strategy for these individuals.
... By comparison, few studies have specifically used this technology to assess the energetic consequences of travelling in different terrains [18]. Higher energetic costs are presumed to occur in more challenging environments such as thick vegetation and sandy soils [19,20]. Similarly, locomotion on inclines can instigate an increase in energy expenditure compared to that incurred on level ground [21]. ...
... This study investigated a single environmental challenge for pumas -incline locomotion -that must be considered in the context of other associated environmental factors that can affect overall energetic costs [19,20]. Incline avoidance behaviours indicate a 'path of least resistance' strategy used by the pumas to decrease locomotion costs that will have an advantage through energetic conservation [48] especially in complex, costly habitats [14,49]. ...
Article
Full-text available
Background: Under current scenarios of climate change and habitat loss, many wild animals, especially large predators, are moving into novel energetically challenging environments. Consequently, changes in terrain associated with such moves may heighten energetic costs and effect the decline of populations in new localities. Methods: To examine locomotor costs of a large carnivorous mammal moving in mountainous habitats, the oxygen consumption of captive pumas (Puma concolor) was measured during treadmill locomotion on level and incline (6.8°) surfaces. These data were used to predict energetic costs of locomotor behaviours of free-ranging pumas equipped with GPS/accelerometer collars in California's Santa Cruz Mountains. Results: Incline walking resulted in a 42.0% ± 7.2 SEM increase in the costs of transport compared to level performance. Pumas negotiated steep terrain by traversing across hillsides (mean hill incline 17.2° ± 0.3 SEM; mean path incline 7.3° ± 0.1 SEM). Pumas also walked more slowly up steeper paths, thereby minimizing the energetic impact of vertical terrains. Estimated daily energy expenditure (DEE) based on GPS-derived speeds of free-ranging pumas was 18.3 MJ day- 1 ± 0.2 SEM. Calculations show that a 20 degree increase in mean steepness of the terrain would increase puma DEE by less than 1% as they only spend a small proportion (10%) of their day travelling. They also avoided elevated costs by utilizing slower speeds and shallower path angles. Conclusions: While many factors influence survival in novel habitats, we illustrate the importance of behaviours which reduce locomotor costs when traversing new, energetically challenging environments, and demonstrate that these behaviours are utilised by pumas in the wild.
... It is energetically more expensive for humans to walk on natural, complex terrain than 2 on hard, flat surfaces [1][2][3][4][5]. A multitude of factors, such as terrain unevenness, damping, 3 stiffness, friction, and other surface characteristics can affect gait biomechanics and 4 energy expenditure. ...
... It is energetically more expensive for humans to walk on natural, complex terrain than 2 on hard, flat surfaces [1][2][3][4][5]. A multitude of factors, such as terrain unevenness, damping, 3 stiffness, friction, and other surface characteristics can affect gait biomechanics and 4 energy expenditure. Such potential causes for increases in energy consumption can be 5 roughly classified into two categories: gait adaptations that facilitate control or preempt 6 falls when walking under more challenging conditions and gait adaptations that are 7 mechanically necessary to account for terrain variation. ...
Preprint
Full-text available
Human walking on uneven terrain is energetically more expensive than on flat, even ground. This is in part due to increases in, and redistribution of positive work among lower limb joints. To improve understanding of the mechanical adaptations, we performed analytical and computational analyses of simple mechanical models walking over uneven terrain comprised of alternating up and down steps of equal height. We simulated dynamic walking models using trailing leg push-off and/or hip torque to power gait, and quantified the compensatory work costs vs. terrain height. We also examined the effect of swing leg dynamics by including and excluding them from the model. We found that greater work, increasing approximately quadratically with uneven terrain height variations, was necessary to maintain a prescribed average forward speed. Greatest economy was achieved by modulating precisely-timed push-offs for each step height. Least economy was achieved with hip power, which did not require as precise timing. This compares well with observations of humans on uneven terrain, showing similar near-normal push-off but with more variable step timing, and considerably more hip work. These analyses suggest how mechanical work and timing could be adjusted to compensate for real world environments.
... One important way that animals use to optimise their locomotion is the minimisation of the energy cost 127,154,155 . Walking and running on irregular natural or artificial terrain as swamp, loam, stubble, grass, sand, snow, rubber, mountain trail and uneven-surface treadmill [156][157][158][159][160][161][162][163][164][165] has often been found to be more expensive than steady locomotion over even, solid surfaces. ...
... However, optimisation of economy does not fully explain the movement strategies employed by humans and other animals 166 . Increased energy expenditure has been often found for walking and running on irregular natural or artificial terrain as swamp, loam, stubble, grass, sand, snow, rubber, mountain trail and uneven-surface treadmill [156][157][158][159][160][161][162][163][164][165] . Studies showed that destabilising environments can decrease dynamic stability during walking [170][171][172] . ...
Thesis
Full-text available
The need to move over uneven, continuously changing terrains is part of our daily life. Thus, the central nervous system must integrate an augmented amount of information in order to be able to cope with the unpredictability of external disturbances. A consequence of this increased demand might be a flexible recombination of the modular organisation of movement creation and control. At the expense of motion’s accuracy, it is possible that the system responds by increasing its control’s robustness (i.e. ability to cope with errors). However, the strategies employed by the central nervous system to organise movement are still poorly understood. One possibility is that movements are constructed through a small amount of linearly combined patterns of activations, called muscle synergies. Amongst the several possibilities of perturbing locomotion, the removal of footwear and the use of uneven surfaces are two valid options. In a first step, I conducted a thorough analysis of the methodologies useful for a) the evaluation of spatiotemporal gait parameters using plantar pressure distribution data and b) the extraction of muscle synergies using non-negative matrix factorisation. Afterwards, I analysed the modular organisation of c) shod and barefoot running and d) walking and running over an even- and an uneven-surface treadmill. The modular organisation of locomotion, assessed through the extraction of muscle synergies, changed when perturbations were introduced. Compared to the shod condition, barefoot running underwent, mostly due to the different foot strike pattern, a reorganisation of the time-independent coefficients (motor modules) and a time-shift of the time-dependent muscle activation patterns (motor primitives). Uneven-surface locomotion, compared to even-surface, conserved motor modules, while motor primitives were generally wider, confirming the idea of an increased robustness in motor control during unsteady locomotion.
... 19 Besides, many studies show that sand allows an improvement in performance, at least at the same level as other surfaces. 4,11,[20][21][22][23][24][25] On the other hand, during daily training sessions, the use of global positioning system (GPS) devices has become widespread as a tool to control external load. These apparatus allows to obtain information about players' position from triangulation obtained from a satellite network, while using inertial movement units that includes 3 triaxial accelerometer and 3 gyroscopes to improve kinematic information. ...
Article
Full-text available
En el ámbito deportivo, el uso de la arena como superfície de trabajo dentro del proceso de recuperación de las lesiones, ha disfrutado de muy buena aceptación y de un creciente interés en los últimos años. Desafortunada-mente, el número de estudios en los que se ha analizado sus efectos continúa siendo reducido. Por ello, en este estudio se analiza la existencia de posibles diferencias en la magnitud del impacto generada durante un Drop Jump (DJ) de 45 cm, en función de la zona corporal analizada, de la superficie de contacto y de la altura en la que es colocada una unidad de movimiento inercial (IMU). Para ello se analizaron a 6 participantes mediante 3 sensores IMU (WIMU PRO™) que se utilizaron para medir las fuerzas G en la fase de aterrizaje del DJ. Los resultados sugieren la existencia de diferencias estadísticamente significativas al comparar superfícies (arena vs. césped), zona corporal (tobillo y lumbar) y lugar de colocación del dispositivo (zona torácica vs. tobillo). A B S T R A C T In sports, the use of sand surface as a tool in the injury recovery process has received very good acceptance and an increased attention in recent years. Unfortunately , the number of studies in this area continues being scarce. Therefore, this study analyzes the existence of possible differences in the magnitude of the impact generated during a 45 cm Drop Jump (DJ), depending on the body area analyzed, the contact surface (sand or grass) and the height (thoracic spine and ankle) at which a jump is placed. To that purpose, 6 participants were analyzed by wearing 3 IMU sensors (WIMU PRO™) to measure G foreces in the landing phase of the DJ. The results suggest the existence of statistically significant differences when comparing surfaces (sand vs. grass),
... The effects held after accounting for participants' personal age-graded score (which showed that comparatively fitter runners had lower likelihood to be High Maintainers or Decliners). Strong inverse effects of belonging to a higher attendance group were also seen where the PA norm was higher (up to 17% lower odds) and the course surface contained sand (34-62% lower odds), a much more difficult surface to run on (Pinnington and Dawson, 2001) along with significant but weaker effects for increasing total elevation and increasing maximum gradient. Together these results suggest that challenging sites, whether through increased local competition (despite personal ability) or running conditions, are associated with less sustained attendance. ...
Article
Full-text available
Most physical activity (PA) maintenance research has concerned adherence to small-scale interventions or infrequent observation in cohort studies. We analysed individual attendance trajectories and their drivers in a large-scale ‘real-world’ community-based weekly PA event (parkrun) cohort in Australia. Data were weekly attendance (walking/running) of 223 224 unique parkrun participants over their first 3 years of participation. An unweighted moving average of participation in the preceding 12 weeks from the 12th week since the first participation to the 156th week was calculated and submitted to a cluster analysis of attendance patterns. Association of individual- (demographic, personal parkrun performance) and site-level (aggregated site-level participant characteristics and area-level measures) covariates with cluster membership was estimated with multinomial logistic regression models. We identified four groups: Few-Timers (76.4%), Decliners (12.4%), Low Maintainers (6.9%) and High Maintainers (4.3%). In the first 12 weeks, attendances averaged 2, 6, 5 and 7.5 times for each cluster, respectively, and by 52 weeks, they were 0.17, 1.9, 3.4 and 7.6 times, respectively. Continuing participation (vs Few-Timers) was strongly associated with faster personal finish times, but slower performance at the site level. Higher running club/group membership at a participant’s parkrun predicted higher odds of being a High Maintainer. Our identification of a Low Maintainer group shows a community-based initiative may sustain interest, despite not requiring continuous or near-continuous attendance. Where someone is placed ‘in the pack’ locally and degree of identification with others in the group may be bidirectionally associated with attendance, underscoring the importance of considering social environment of PA maintenance.
... The energy cost (EC) and kinematics of various forms of locomotion (e.g., running) have been analyzed in numerous investigations [1][2][3][4][5][6][7] with the aim of elucidating the main mechanisms of different movements. These studies have practical applications and allow for evaluating the metabolic energy expenditure or predicting the "ideal" performance [8][9][10][11][12][13][14] based on the relationship between mechanics and energetics [7,[15][16][17][18][19], which is one of the most crucial and extensively researched domains of human movement [3,4,16,[20][21][22][23][24][25][26][27]. ...
Article
Full-text available
Sprinting is a decisive action in soccer that is considerably taxing from a neuromuscular and energetic perspective. This study compared different calculation methods for the metabolic power (MP) and energy cost (EC) of sprinting using global positioning system (GPS) metrics and electromyography (EMG), with the aim of identifying potential differences in performance markers. Sixteen elite U17 male soccer players (age: 16.4 ± 0.5 years; body mass: 64.6 ± 4.4 kg; and height: 177.4 ± 4.3 cm) participated in the study and completed four different submaximal constant running efforts followed by sprinting actions while using portable GPS-IMU units and surface EMG. GPS-derived MP was determined based on GPS velocity, and the EMG-MP and EC were calculated based on individual profiles plotting the MP of the GPS and all EMG signals acquired. The goodness of fit of the linear regressions was assessed by the coefficient of determination (R 2), and a repeated measures ANOVA was used to detect changes. A linear trend was found in EMG activity during submaximal speed runs (R 2 = 1), but when the sprint effort was considered, the trend became exponential (R 2 = 0.89). The EMG/force ratio displayed two different trends: linear up to a 30 m sprint (R 2 = 0.99) and polynomial up to a 50 m sprint (R 2 = 0.96). Statistically significant differences between the GPS and EMG were observed for MP splits at 0-5 m, 5-10 m, 25-30 m, 30-35 m, and 35-40 m and for EC splits at 5-10 m, 25-30 m, 30-35 m, and 35-40 m (p ≤ 0.05). Therefore, the determination of the MP and EC based on GPS technology underestimated the neuromuscular and metabolic engagement during the sprinting efforts. Thus, the EMG-derived method seems to be more accurate for calculating the MP and EC in this type of action.
... That is more complex and energetically more demanding. Energy consumption during walking or running on sand is about 20% higher than on a hard surface [4][5][6][7][8] and matches are played in more difficult conditions that include harsh sun, wind, and even rain (until the moment where weather conditions present harm to players' health). Beach volleyball players must be universally skilled (perform all techniques equally well), while volleyball players are specialized in specific playing tasks. ...
Article
Full-text available
The aim of this research is to verify whether there is a difference in the average duration of the active and passive phases of the game between volleyball and beach volleyball. A total of 2392 active and passive phases were measured during high-level volleyball and beach volleyball matches for males. Matches were played by four teams (53 players) in indoor volleyball (age 29 ± 4.94 years) and five teams (10 players) in beach volleyball (age 28.27 ± 6.64 years). Possible differences were evaluated using the Mann-Whitney U test. The average duration of the active phase in volleyball is 5.55 s ± 4.38 s. In beach volleyball, the active phase lasts marginally longer, at 6.00 s ± 3.44 s. The average duration of the passive phase in volleyball is 35.27 s ± 25.96 s and it lasts longer than the average passive phase in beach volleyball at 33.82 s ± 22.98 s. The Mann-Whitney U test showed a statistically significant difference (p = 0.00) between the active phases in volleyball (Md = 3.53, n = 727) and beach volleyball (Md = 3.43, n = 484), U = 140770.00, z = −5.90 with small effect according to Cohen's criterion (r = 0.14). The Mann-Whitney U test (U = 160773.00, z = −1.10) showed no statistically significant difference in the average duration of the passive phases at volleyball and beach volleyball. This research determined that there is a statistically significant difference in the average duration of the active phase between volleyball and beach volleyball. The new insights gained in this research can support a more precise programming of training intensity in high-level volleyball and beach volleyball.
... In the case of sand, it is evident in the literature that energy expenditure (Zamparo et al., 1992;Pinnington & Dawson, 2001a& 2001b, as well as the response of maximal oxygen consumption, peak heart rate value, exertion perception and lactate, are significantly higher when analysing high and very high intensity exercise (Cetolin et al., 2021). ...
Article
Full-text available
Study purpose. The aim of the study was to evaluate jumping performance and lower limbs strength asymmetry in young soccer players by comparing this movement performed on both a conventional surface and a sand surface. Materials and methods. 20 young soccer players under 17 years old randomly performed a standing long jump, a single hop jump in the sagittal plane (Hop Jump Test) and a single side hop jump in the frontal plane (Side Hop Jump Test), first on a conventional surface (natural grass) and then on sand. The jump distance and strength asymmetry was calculated using the formula: (NDL / DL) x 100. Results. The values from the two different jumping conditions showed a statistically significant decrease in the Broad Jump Test (p<0.001, ES: 3.56), Hop Jump Test left limb (p<0.001, ES: 4.99), Hop Jump Test right limb (p<0.001, ES: 3.95), Side Hop Jump Test left limb (p<0.001, ES: 4.67) and Side Hop Jump Test right limb (p<0.001, ES: 2.98) in the sand condition. The asymmetry values in the Hop Jump Test and the Side Hop Jump Test showed a statistically significant increase (+21.5%, p<0.001, ES: 3.66 and +41.1%, p<0.001, ES: 1.99, respectively) when comparing the performance on grass and sand. Conclusions. This different performance response in the two different jumping modes leads to the hypothesis that young soccer players who want to stress their explosive strength ability and joint stability should favor the use of one-leg rather than two-leg jumps. The values described in the study lead to the hypothesis that training on sand should be suggested when the young soccer player presents modest values of inter-limb asymmetry measured on a conventional surface.
... Even so, it is probable that trail running may elicit greater benefits for cardiovascular fitness. Several studies [26,[50][51][52][53] documented that running on natural surfaces such as irregular trails required a higher energy expenditure and metabolic cost, which translated to a higher training intensity and higher aerobic training adaptations. However, recorded RPE from the running logs revealed no group differences (4.6 ± 1.1 for TRAIL; 4.9 ± 0.8 for ROAD), an interesting finding if greater energy expenditure is realized on TRAIL versus ROAD without a concurrent rise in RPE. ...
Article
Full-text available
Running on less predictable terrain has the potential to increase the stimulation of the neuromuscular system and can boost aerobic performance. Hence, the purpose of this study was to analyze the effects of trail versus road running on neuromuscular and endurance performance parameters in running novices. Twenty sedentary participants were randomly assigned to either a trail (TRAIL; n = 10) or road running (ROAD; n = 10) group. A supervised and progressive, moderate intensity, and work-load-matched 8 wk endurance running program on TRAIL or ROAD was prescribed (i.e., randomized). Static balance (BESS test), dynamic balance (Y-balance test), gait analysis (RehaGait test, with regard to stride time single task, stride length dual task, velocity single task), agility performance (t-test), isokinetic leg strength (BIODEX), and predicted VO2max were assessed in pre- and post-tests. rANOVA analysis revealed no significant time–group interactions. Large effect sizes (Cohen’s d) for pairwise comparison were found for TRAIL in the BESS test (d = 1.2) and predicted (pred) VO2max (d = 0.95). Moderate effects were evident for ROAD in BESS (d = 0.5), stride time single task (d = 0.52), and VO2max predicted (d = 0.53). Possible moderate to large effect sizes for stride length dual task (72%), velocity single task (64%), BESS test (60%), and the Y-balance test left stance (51%) in favor of TRAIL occurred. Collectively, the results suggested slightly more beneficial tendencies in favor of TRAIL. Additional research is needed to clearly elucidate differences between TRAIL and ROAD, not only in novices but also in experienced exercisers.
... Importantly, the s-RPE values of both groups were similar for soccer training sessions and friendly matches, and when comparing sand and grass training sessions. The latter finding is especially relevant,since previous studies reported that training on sand is associated with greater metabolic energy cost[9] and lactate accumulation[24], compared to harder surfaces, which, theoretically, may result in higher perceived training loads. However, the high-speed impacts and high application of eccentric forces against hard surfaces may be more demanding for the soccer players, which, in turn, could equalize and balance the overall training stimulus, leading athletes from both groups to report similar perceived training loads after the sprint-jump training sessions. ...
Article
Full-text available
This study compared the effects of two sprint-jump training programs, performed on either sand or grass surfaces, on the sprint and jump performance of elite young soccer players over an 8-week training period. Fifteen under-20 soccer players were randomly allocated to sand (n=7) or grass (n=8) groups. Athletes performed 12 training sessions, comprising vertical and horizontal jump exercises, and linear and change-of-direction (COD) sprint drills. Pre- and post-measurements were completed in the following order: vertical jump, sprint speed at 10- and 17-m, curve sprint (CS), and modified Zigzag COD tests. Between-group differences were determined using an ANOVA two-way with repeated measures and effect sizes (ES). No improvements in jump performance were found in any of the groups. Significant increases were observed in the sand group for acceleration in 0-10-m and for 10- and 17-m linear sprint velocity (ES = 1.15, 1.16, and 1.81, respectively; P< 0.05). In contrast, no significant differences were detected for acceleration and linear sprint velocity in the grass group, comparing pre- and post-tests (ES ranging from 0.01 to 0.47; P>0.05). Both sand and grass groups revealed similar increases in the CS and COD velocities after the training period (ES ranging from 0.98 to 1.93; P<0.05). In conclusion, sprint-jump training programs performed on both grass and sand surfaces elicited significant improvements in CS and COD performances, whereas acceleration and linear sprint velocity increased only in the sand group, after a short-term training period. The sand training surface was proven to be a practical strategy to improve sprint performance in all its forms in soccer players, which is of great interest and importance for coaches and sport scientists working in elite soccer.
... Running on soft surfaces such as sand and grass are an interesting alternative to reduce instantaneous impact loading (Tessutti et al. 2012), while also increasing running Communicated by Toshio Moritani. metabolic cost (Pinnington and Dawson 2001). Performing running workouts on natural grass may be highly relevant for people seeking to lose weight and/or people affected by musculoskeletal disorders and lower limb/trunk pain (Nejati et al. 2011;Tessutti et al. 2010). ...
Article
Full-text available
Running is an exercise that can be performed in different environments that imposes distinct foot–floor interactions. For instance, running on grass may help reducing instantaneous vertical impact loading, while compromising natural speed. Inter-muscular coordination during running is an important factor to understand motor performance, but little is known regarding the impact of running surface hardness on inter-muscular coordination. Therefore, we investigated whether inter-muscular coordination during running is influenced by running surface. Surface electromyography (EMG) from 12 lower limb muscles were recorded from young male individuals (n = 9) while running on grass, concrete, and on a treadmill. Motor modules consisting of weighting coefficients and activation signals were extracted from the multi-muscle EMG datasets representing 50 consecutive running cycles using non-negative matrix factorization. We found that four motor modules were sufficient to represent the EMG from all running surfaces. The inter-subject similarity across muscle weightings was the lowest for running on grass (r = 0.76 ± 0.11) compared to concrete (r = 0.81 ± 0.07) and treadmill (r = 0.78 ± 0.05), but no differences in weighting coefficients were found when analyzing the number of significantly active muscles and residual muscle weightings (p > 0.05). Statistical parametric mapping showed no temporal differences between activation signals across running surfaces (p > 0.05). However, the activation duration (% time above 15% peak activation) was significantly shorter for treadmill running compared to grass and concrete (p < 0.05). These results suggest predominantly similar neuromuscular strategies to control multiple muscles across different running surfaces. However, individual adjustments in inter-muscular coordination are required when coping with softer surfaces or the treadmill’s moving belt.
... Whether our findings can be translated to barefoot runners or hindfoot strike runners has to be clarified in future research. A previous study reported that running on sand produces higher energy costs compared with running on grass (Pinnington and Dawson, 2001). In addition, running on sand compared with firm ground resulted in greater hamstring, vastus lateralis, vastus medialis, and rectus femoris activities (Pinnington et al., 2005). ...
Article
Full-text available
Background: In terms of physiological and biomechanical characteristics, over-pronation of the feet has been associated with distinct muscle recruitment patterns and ground reaction forces during running. Objective: The aim of this study was to evaluate the effects of running on sand vs. stable ground on ground-reaction-forces (GRFs) and electromyographic (EMG) activity of lower limb muscles in individuals with over-pronated feet (OPF) compared with healthy controls. Methods: Thirty-three OPF individuals and 33 controls ran at preferred speed and in randomized-order over level-ground and sand. A force-plate was embedded in an 18-m runway to collect GRFs. Muscle activities were recorded using an EMG-system. Data were adjusted for surface-related differences in running speed. Results: Running on sand resulted in lower speed compared with stable ground running (p < 0.001; d = 0.83). Results demonstrated that running on sand produced higher tibialis anterior activity (p = 0.024; d = 0.28). Also, findings indicated larger loading rates (p = 0.004; d = 0.72) and greater vastus medialis (p < 0.001; d = 0.89) and rectus femoris (p = 0.001; d = 0.61) activities in OPF individuals. Controls but not OPF showed significantly lower gluteus-medius activity (p = 0.022; d = 0.63) when running on sand. Conclusion: Running on sand resulted in lower running speed and higher tibialis anterior activity during the loading phase. This may indicate alterations in neuromuscular demands in the distal part of the lower limbs when running on sand. In OPF individuals, higher loading rates together with greater quadriceps activity may constitute a proximal compensatory mechanism for distal surface instability.
... Whether our findings can be translated to barefoot runners or hindfoot strike runners has to be clarified in future research. A previous study reported that running on sand produces higher energy costs compared with running on grass (Pinnington and Dawson, 2001). In addition, running on sand compared with firm ground resulted in greater hamstring, vastus lateralis, vastus medialis, and rectus femoris activities (Pinnington et al., 2005). ...
Article
Full-text available
Background: In terms of physiological and biomechanical characteristics, over-pronation of the feet has been associated with distinct muscle recruitment patterns and ground reaction forces during running. Objective: The aim of this study was to evaluate the effects of running on sand vs. stable ground on ground-reaction-forces (GRFs) and electromyographic (EMG) activity of lower limb muscles in individuals with over-pronated feet (OPF) compared with healthy controls. Methods: Thirty-three OPF individuals and 33 controls ran at preferred speed and in randomized-order over level-ground and sand. A force-plate was embedded in an 18-m runway to collect GRFs. Muscle activities were recorded using an EMG-system. Data were adjusted for surface-related differences in running speed. Results: Running on sand resulted in lower speed compared with stable ground running (p < 0.001; d = 0.83). Results demonstrated that running on sand produced higher tibialis anterior activity (p = 0.024; d = 0.28). Also, findings indicated larger loading rates (p = 0.004; d = 0.72) and greater vastus medialis (p < 0.001; d = 0.89) and rectus femoris (p = 0.001; d = 0.61) activities in OPF individuals. Controls but not OPF showed significantly lower gluteus-medius activity (p = 0.022; d = 0.63) when running on sand. Conclusion: Running on sand resulted in lower running speed and higher tibialis anterior activity during the loading phase. This may indicate alterations in neuromuscular demands in the distal part of the lower limbs when running on sand. In OPF individuals, higher loading rates together with greater quadriceps activity may constitute a proximal compensatory mechanism for distal surface instability.
... Despite its potential, the biomechanical quantitative characterization of walking on compliant surfaces and on sand, in particular, is still significantly lacking [14]. Studies assessing walking on sand and performed in natural beach environment investigated energy consumption [15], while quantitative analysis of gait timing, joint kinematics, and mechanical work has been performed using stereophotogrammetry [6], force platforms [10], or inertial measurement units (IMUs) [7] only in controlled laboratory conditions on short length paths (from 6 m to 10 m [6,7,10]), with difficulties in the replication of the sand surface and far from any ecological evaluation. ...
Article
Background Walking on compliant surfaces, on sand in particular, is now recommended for training in both elderlies and injured subjects/individuals, allowing to perform high intensity exercises (i.e. augmented energy expenditure) in safe conditions (i.e. minimizing the impact on the joints and the risk of fall). Nevertheless, despite the assessment of energetics of walking on sand, the quantitative biomechanical characterization of walking on sand in ecological conditions is largely lacking. Research question Which is the effect of sand surface on gait speed, gait temporal segmentation and their variability as related to surface compliance in ecological condition? Methods Eighteen healthy adults were assessed while walking on solid ground, dry-, and wet sand in ecological conditions by means of wearable inertial sensors (Miniwave, Cometa s.r.l., Italy). The best performing algorithm for the segmentation of walking on sand was selected among 17 algorithms designed for solid ground. Gait timing (i.e. speed, temporal segmentation, variability) was analysed, for the first time, with respect to sand compliance, and compared to walking on solid ground. Results Self-selected speed on a 60 m distance increased when walking on sand with respect of solid ground (Median 1.02 m/s), with the highest speed on wet sand (Median 1.15 m/s). A stabilizing strategy on the uneven surface provided by sand was highlighted by i) increased stance and double support durations with respect to speed on wet sand, and ii) increased short-term variability of stride, corresponding to continual adjustments of the lower limbs due to shifting surface provided by sand. Significance. This study represents the first step in the objective characterization of walking on compliant surfaces as sand, necessary for the definition of training and rehabilitative programs.
... These results were superior to the data obtained by Zapardiel and Asín-Izquierdo [9] with a mean of 369.7 ± 158.4 (m), and by Gutiérrez-Vargas et al. [45] with 332.2 ± 134.7 (m) travelled in the first set and 281.2 ± 87.7 (m) in the second set, and lower than those achieved by Pueo et al. [8] with 614 ± 145 (m) in the first set and 504 ± 130 (m) in the second. The differences in the distances covered may be due to the heterogeneity in the study samples or the differences in the playing surfaces that present a variable and non-standardized depth, the mechanical properties of sand being one of the determining variables of the performance in the players [46]. The analysis of the distance travelled in the different speed zones does not follow the same methodological definition due to the differences in the definition of the speed ranges used in the studies. ...
Article
Full-text available
This cross-sectional study aims to analyze the physical demands of elite beach handball players during an official competition. Nine elite female (mean age: 24.6 ± 4.0 years; body weight: 62.4 ± 4.6 kg; body height: 1.68 ± 0.059 m; training experience: 5 years; training: 6 h/week) beach handball players of the Spanish National Team were recruited for this study. A Global Positioning System was incorporated on each player’s back to analyze their movement patterns. Speed and distance were recorded at a sampling frequency of 15 Hz, whereas acceleration was recorded at 100 Hz by means of a built-in triaxial accelerometer. The main finding of the study is that 53% of the distance travelled is done at speeds between 1.5 and 5 km/h and 30% of the distance is between 9 and 13 km/h (83% of the total distance covered), which shows the intermittent efforts that beach handball involves at high intensity, as reflected in the analysis of the internal load with 62.82 ± 14.73% of the game time above 80% of the maximum heart rate. These data help to orientate training objectives to the physical demands required by the competition in order to optimize the players’ performance.
... Research has shown several differences in physical and physiological factors when performing jumping and sprinting activities on sand or hard surfaces (2,24,43). For example, it has been observed that movements on sand have a higher energy cost (34,59) and lead to greater lactate accumulation (49) and higher lower-limb muscles activation (43,50,56) when compared with harder surfaces (10)(11)(12). Because of the high demands of muscle activity, sand surfaces can also work as a natural and effective way to increase movement resistance, inducing critical adaptations in different physiological, mechanical, and neuromuscular factors (e.g., increased muscle-tendon unit stiffness, motor unit recruitment, and neurological drive), especially when athletes are chronically exposed to this training strategy (30,33,55). ...
Article
We examined the effectiveness of training on sand and compared the effects of sand and hard surface training programs on the sprint and jump performance of team-sport players. PubMed MEDLINE, SPORTDiscus, and Web of Science databases were used in the literature search. A total of 377 records were initially identified and six studies comprising 136 athletes were included in the meta-analysis. Pre- and post-comparisons showed that sand training interventions were effective at improving both jump and sprint capacities. When comparing sand and hard surfaces, no significant differences in favor of any of the interventions were observed. In summary, this review revealed that sand training is an efficient strategy to improve jump and sprint performances in team-sport players. Moreover, sand surfaces produced similar gains to those observed after hard surface training schemes. Strength and conditioning coaches and sport scientists who work with team-sports can use both sand and hard surface training programs as part of their regular training practices, during distinct phases of the season.
... These differences confirm the hypothesis that softer surfaces require greater energy [45,46]. The deterioration in sprint performance on sand can be due to lower muscle-sinew efficiency [47] or to greater hip and knee flexion [48], as a consequence of a larger impact reduction on sand, even more pronounced during the acceleration phase or in short sprints, because of longer contact times [49]. ...
Article
Full-text available
The aim of this study was to analyze the influence of natural turf, artificial turf, and sand on sprint performance in different sports and to determine how the sport surface affects sprint performance. A systematic search was conducted in Pubmed, Web of Sciences, and SPORTDiscus databases. Out of 5644 studies, 11 studies were included in the meta-analysis. The studies were very heterogeneous, as they examined different structural characteristics or quality parameters. The studies on natural turf and sand showed significant improvements on sprint speed during training. On the other hand, the analysis of fatigue did not reveal significant differences in the deterioration of sprint speed on both natural and artificial turf. Significance was set at p < 0.05. In conclusion, although lower performance in sprint was reported on sand, further studies are needed to explain the differences in sprint on natural and artificial turf.
... Despite studies addressing balance training in volleyball [12,[26][27][28], no study related to beach volleyball has been found. Therefore, it would be interesting to explore the effect of balance training in a discipline played on unstable surfaces [29], where demands of motor control are higher than on stable surfaces [30]. In the same way, it would be useful to know if sand training can be a substitute for classical balance training in elite beach athletes with advanced motor skills to maintain balance. ...
Article
Full-text available
The aim of this work was to evaluate the effectiveness of a 12-week-long balance training program on the postural control of elite male beach volleyball players and the effect on balance when swapping to specific sports training in the sand in the following 12 weeks. Six elite players were tested before and after the balance training program and also 12 weeks after the balance training had finished. To this aim, a pressure platform was used to collect the following center of pressure parameters: path length, speed, mean position, and root-mean-square amplitude in the medial-lateral and anteroposterior planes. Romberg quotients for the center of pressure parameters were also calculated. The results of the present study showed better static postural control after specific balance training: smaller path length and speed under open eyes condition in dominant (p = 0.015; p = 0.009, respectively) and non-dominant monopedal stances (p = 0.005; p = 0.004, respectively). Contrastingly, 12 weeks after the balance training program, the path length and speed values under open eyes condition in bipedal stance increased significantly (p = 0.045; p = 0.004, respectively) for sand training. According to our results, balance training is effective to achieve positive balance test scores. It is speculated, and yet to be proven, that sand training could be effective to improve dynamic and open eyes postural control during beach volleyball practice. In beach volleyball players, a balance training program is effective to develop static balance but the effect of ecological sand training on dynamic performance deserves specific investigation.
... Our results show a greater dispersion of treadmills' mechanical properties compared to those of artificial turf and track surfaces ( Figure 1). Our findings on the relationship between SA, VD and ER in artificial turf and track surfaces support previous studies reporting that an increased compliance (i.e., higher VD) in overground surfaces is associated with a reduction in the re-utilization of elastic energy (i.e., a lower ER) [38][39][40], which would lead to an increased metabolic cost and alterations in running kinematics. However, as opposed to overground surfaces, both SA and VD are directly proportional to ER in treadmills, meaning that treadmills with more shock-absorbing and compliant surfaces would increase energy return to the runners. ...
Article
Full-text available
The mechanical properties of the surfaces used for exercising can affect sports performance and injury risk. However, the mechanical properties of treadmill surfaces remain largely unknown. The aim of this study was, therefore, to assess the shock absorption (SA), vertical deformation (VD) and energy restitution (ER) of different treadmill models and to compare them with those of other sport surfaces. A total of 77 treadmills, 30 artificial turf pitches and 30 athletics tracks were assessed using an advanced artificial athlete device. Differences in the mechanical properties between the surfaces and treadmill models were evaluated using a repeated-measures ANOVA. The treadmills were found to exhibit the highest SA of all the surfaces (64.2 ± 2; p < 0.01; effect size (ES) = 0.96), while their VD (7.6 ± 1.3; p < 0.01; ES = 0.87) and ER (45 ± 11; p < 0.01; ES = 0.51) were between the VDs of the artificial turf and track. The SA (p < 0.01; ES = 0.69), VD (p < 0.01; ES = 0.90) and ER (p < 0.01; ES = 0.89) were also shown to differ between treadmill models. The differences between the treadmills commonly used in fitness centers were much lower than differences between the treadmills and track surfaces, but they were sometimes larger than the differences with artificial turf. The treadmills used in clinical practice and research were shown to exhibit widely varying mechanical properties. The results of this study demonstrate that the mechanical properties (SA, VD and ER) of treadmill surfaces differ significantly from those of overground sport surfaces such as artificial turf and athletics track surfaces but also asphalt or concrete. These different mechanical properties of treadmills may affect treadmill running performance, injury risk and the generalizability of research performed on treadmills to overground locomotion.
... Sassi et al. [8] previously reported that an increase in SA of the surface in question is the main mechanical property responsible for a reduction in elastic energy recovery and in overall muscle-tendon efficiency, thereby resulting in greater muscle work and higher energy demands. Although they did not actually use a treadmill, these authors estimated that an increase in SA of approximately 35% will result in an increase in the cost of running of 5%, complementing previous findings that the mechanical behavior of the surface affects muscle force generation and running economy [32][33][34][35], and supporting those who later reported varying injury risk and effort perception [36,37]. In addition, in a systematic review Miller et al. [38] found that endurance running performance is generally poorer on a motorized treadmill compared to overground, which could partly be related to differences in surface stiffness. ...
Article
Full-text available
The aim of this study was to define a reliable and sensitive test method for assessing Shock Absorption (SA), Vertical Deformation (VD), and Energy Restitution (ER) in treadmill surfaces. A total of 42 treadmills belonging to four different models were included in the study: (a) Technogym Jog700 Excite (n = 10), (b) Technogym Artis Run (n = 12), (c) LifeFitness Integrity Series 97T (n = 11), and (d) LifeFitness Integrity Series DX (n = 9). An advanced artificial athlete (AAA) device was used to assess SA, VD, and ER at three different locations along the longitudinal axis of each treadmill and in the support area of the athletes' feet. For each location, our results show that the error assumed when performing one impact with the AAA instead of three (SA ≤ |0.1|%, VD ≤ |0.0| mm, and ER ≤ |0.2|%) is lower than the smallest changes that can be detected by the measuring device (SA = 0.4%, VD = 0.2 mm, and ER = 0.9%). Also, our results show the ability of the test method to detect meaningful differences between locations once the one-impact criterium is adopted, since absolute minimum differences between zones (SA: |0.6|%, VD: |0.3| mm, and ER: |1.2|%) were above the uncertainty of the measuring device. Therefore, performing a single impact with the AAA in each of the three locations described in this study can be considered a representative and reliable method for assessing SA, VD, and ER in treadmill surfaces.
... Substrate is defined as 'the medium over or on which an animal moves' (Shepard et al., 2013, p. 299), and superstrate as 'any material against which an animal must push to move' (Shepard et al., 2013, p. 300). Humans expend 1.7 to 2.7 times more energy walking on soft substrates such as sand than firmer substrates such as concrete (Pinnington & Dawson, 2001). For terrestrial animals, superstrate includes any material that extends above the substrate, with taller, denser and more rigid superstrates being more costly (Shepard et al., 2013). ...
Article
Recent improvements in tracking technologies have resulted in a growing number of fine-scale animal movement studies in a variety of fields, from wildlife management to animal cognition. Most studies assume that an animal's ‘optimal’ foraging route is linear, ignoring the role the energy landscape can play in influencing movement efficiency. Our objective was to investigate whether landscape features that affect movement costs (topographical variation, superstrate and substrate) influence the movement of chimpanzees, Pan troglodytes, in a rugged, montane environment. We tested for route reuse and preferential use of human-made trails and ridge tops, using 14 months of focal follow data from 14 individuals and maps of established chimpanzee trails. Chimpanzees travelled on human-made trails significantly more than expected and showed weak preference for use of ridge tops for travel. Line density analysis demonstrated route reuse in chimpanzees and uncovered a network of high-use routes across their range. To our knowledge, this is the first study to empirically demonstrate route reuse and preferential use of human-made trails for travel by chimpanzees. We discuss the energetic and cognitive benefits of trail use and the implications for chimpanzee sociality. By applying resource selection and line density analysis to fine-scale movement data, this study demonstrates the importance of incorporating landscape features in predictive animal movement models.
... Substrate is defined as 'the medium over or on which an animal moves' (Shepard et al., 2013, p. 299), and superstrate as 'any material against which an animal must push to move' (Shepard et al., 2013, p. 300). Humans expend 1.7 to 2.7 times more energy walking on soft substrates such as sand than firmer substrates such as concrete (Pinnington & Dawson, 2001). For terrestrial animals, superstrate includes any material that extends above the substrate, with taller, denser and more rigid superstrates being more costly (Shepard et al., 2013). ...
Preprint
Recent improvements in tracking technologies have resulted in a growing number of fine-scale animal movement studies in a variety of fields from wildlife management to animal cognition. Most studies assume that an animal's optimal foraging route is linear, ignoring the role the energy landscape can play in influencing movement efficiency. Our objective was to investigate whether landscape features that affect movement costs; topographic variation, and super and substrate, influence the movement of chimpanzees (Pan troglodytes) in a rugged, montane environment. We tested for route re-use and preferential use of human-made trails and ridge tops using 14 months of focal follow data from 14 individuals and maps of established chimpanzee trails. Chimpanzees travelled on human-made trails significantly more than expected and showed weak preference for use of ridge tops for travel. Line density analysis demonstrated route re-use in chimpanzees and uncovered a network of high-use routes across their range. To our knowledge, this is the first study to empirically demonstrate route re-use and preferential use of human-made trails for travel by chimpanzees. We discuss the energetic and cognitive benefits of trail use and the implications for chimpanzee sociality. By applying the latest GIS analytical techniques to fine-scale movement data, this study demonstrates the importance of incorporating landscape features in predictive animal movement models.
... There are several studies that investigated the metabolic rate of locomotion on natural terrains, but they did not focus on the relationship between optimal speed and preferred speed. For example, walking has been investigated on sand (Pinnington and Dawson, 2001), grass (Davies and Mackinnon, 2006), dirt roads (Daniels et al., 1953) and snow (Pandolf et al., 1976;Soule and Goldman, 1972). Givoni and Goldman (1971) and Pandolf et al. (1977) developed prediction equations for the metabolic cost of load-carrying while walking on different terrains and slopes. ...
Article
Humans have evolved the ability to walk very efficiently. Further, humans prefer to walk at speeds that approximately minimize their metabolic energy expenditure per unit distance (i.e. gross cost of transport, COT). This has been found in a variety of population groups and other species. However, these studies were mostly performed on smooth, level ground or on treadmills. We hypothesized that the objective function for walking is more complex than only minimizing the COT. To test this idea, we compared the preferred speeds and the relationships between COT and speed for people walking on both a smooth, level floor and a rough, natural terrain trail. Rough terrain presumably introduces other factors, such as stability, to the objective function. Ten healthy men walked on both a straight, flat, smooth floor and an outdoor trail strewn with rocks and boulders. In both locations, subjects performed five to seven trials at different speeds relative to their preferred speed. The COT-speed relationships were similarly U-shaped for both surfaces, but the COT values on rough terrain were approximately 115% greater. On the smooth surface, the preferred speed (1.24±0.17 m s-1) was not found to be statistically different (P=0.09) than the speed that minimized COT (1.34±0.03 m s-1). On rough terrain, the preferred speed (1.07±0.05 m s-1) was significantly slower than the COT minimum speed (1.13±0.07 m s-1; P=0.02). Because near the optimum speed the COT function is very shallow, these changes in speed result in a small change in COT (0.5%). It appears that the objective function for speed preference when walking on rough terrain includes COT and additional factors such as stability.
... However, optimisation of economy does not fully explain the movement strategies employed by humans and other animals 10 . Increased energy expenditure has been often found for walking and running on irregular natural or artificial terrain such as swamp, loam, stubble, grass, sand, snow, rubber, mountain trail and uneven-surface treadmill [11][12][13][14][15][16][17][18][19][20] . Studies showed that destabilising environments can decrease dynamic stability during walking 21-23 . ...
Article
Full-text available
The need to move over uneven terrain is a daily challenge. In order to face unexpected perturbations due to changes in the morphology of the terrain, the central nervous system must flexibly modify its control strategies. We analysed the local dynamic stability and the modular organisation of muscle activation (muscle synergies) during walking and running on an even- and an uneven-surface treadmill. We hypothesized a reduced stability during uneven-surface locomotion and a reorganisation of the modular control. We found a decreased stability when switching from even- to uneven-surface locomotion (p < 0.001 in walking, p = 0.001 in running). Moreover, we observed a substantial modification of the time-dependent muscle activation patterns (motor primitives) despite a general conservation of the time-independent coefficients (motor modules). The motor primitives were considerably wider in the uneven-surface condition. Specifically, the widening was significant in both the early (+40.5%, p < 0.001) and late swing (+7.7%, p = 0.040) phase in walking and in the weight acceptance (+13.6%, p = 0.006) and propulsion (+6.0%, p = 0.041) phase in running. This widening highlighted an increased motor output’s robustness (i.e. ability to cope with errors) when dealing with the unexpected perturbations. Our results confirmed the hypothesis that humans adjust their motor control strategies’ timing to deal with unsteady locomotion.
Article
Full-text available
The aim of this study was to assess the effect of six-week sand surface training on the biomechanical variables associated with an anterior cruciate ligament injury in female adolescent futsal players during cutting. The data collected from 12 subjects were recorded before and after 6 weeks of training on the sand surface during 45-and 90-degree cuts by a force plate and cameras. Comparisons between variables in pre-and post-tests were performed using mixed ANOVA. During the initial contact, knee flexion was greater in the cut of 45° than 90° in post-test condition. The peak knee external adduction moment and speed of movement in the anterior-posterior direction increased after training on the sand surface during both 45-and 90-degree cuts. Based on the results, training on the sand surface improved performance through increasing the speed of movement, and on the other hand, increased the load on the knee joint, indicating the need to provide solutions such as technique improvement training along with this protocol.
Article
Full-text available
Zusammenfassung In dieser Arbeit wird ein Überblick über die Methoden zur Messung von Reitbodeneigenschaften, sowie zu den bisher bekannten Einflüssen dieser Eigenschaften auf den Bewegungsapparat des Pferdes gegeben. Der Fokus liegt auf Messmethoden für mechanische Eigenschaften, welche sehr vielfältig sind und von einfachen, unidirektional messenden bis hin zu komplexen Apparaten reichen, die versuchen, den Bewegungsablauf des Pferdes möglichst genau nachzuahmen. Außerdem gibt es Geräte, die in vivo die mechanische Interaktion zwischen Gliedmaße und Boden direkt messen. Eine Kombination verschiedener Methoden, sowie das Einbeziehen anderer Bodeneigenschaften und äußerer Einflüsse ist sinnvoll, um aussagekräftigere und vergleichbarere Schlüsse über Böden und deren Auswirkung auf Pferde zu ziehen. Dazu gehören z.B. die Bodenzusammensetzung, Wetterdaten, Pflegemaßnahmen, aber auch epidemiologische Verletzungsdaten der Pferde oder Computersimulationen. Bis heute gibt es bei Pferdesportveranstaltungen kaum ein Reglement zu verwendeten Böden, jedoch werden deren Effekte auf Leistung und Sicherheit der Pferde mit fortschreitenden Untersuchungen immer offensichtlicher. Einige Faktoren wie z.B. die Bodenhärte, Scherfestigkeit oder Kraftreduktion beim Auffußen sind für ihre Relevanz diesbezüglich bekannt und in einer Vielzahl an Böden untersucht. Anhand solcher Daten gab es beispielsweise im Pferdesport bereits zahlreiche Anpassungen hin zu sichererem Bodenmaterial, eine Optimierung von Pflege und Management der Böden, sowie teilweise die Etablierung verpflichtender Bodentestungen. In jeder Reitsportdisziplin liegen andere Belastungsmuster, Risikofaktoren und Pathologien zugrunde und es besteht, insbesondere in Disziplinen abseits des Rennsportes, noch viel Raum für Forschung und weitere Optimierung der verwendeten Böden. Summary Objective Methods for Measuring Riding Surface Properties and their Influence on the Musculoskeletal System of the Horse – Review This paper presents an overview of the methods for measuring riding surface properties, as well as the known influences of these properties on the musculoskeletal system of the horse. The focus is on methods for measuring mechanical properties. They are very diverse and range from simple, unidirectional methods to complex apparatuses that aim to mimic the horse's movement as closely as possible. There are also devices that measure the mechanical interaction between the limb and the ground directly in vivo. A combination of methods, and incorporating other surface properties and external influences, is useful in drawing meaningful and comparable conclusions about surfaces and their effects on horses. These include substrate composition, weather data and maintenance practices, as well as epidemiological equine injury data and computer simulations. There are still few regulations on surfaces used in equestrian events but their effects on horse performance and safety are becoming more apparent as research progresses. Factors such as hardness, shear strength and force reduction at footing are known to be relevant in this regard and have been studied in a variety of surface types. The data have led to numerous adaptations in equestrian sports, for example towards safer soil material, an optimization of the maintenance and management of the surfaces and the establishment of obligatory soil testing, which varies from region to region. In each equestrian discipline there are different underlying loading patterns, risk factors and pathologies and there is much room for research and further optimization of the surfaces used, especially in disciplines other than racing.
Conference Paper
Physical training of athletes on a sand surface is a method that is increasingly used in recent years. The present study analyzes how different surfaces affect students’ sprint power. The experiment used the “Running Anaerobic Sprint Test”(RAST)- 6 sprints of 35 m, with a break of 10 seconds between them by Mackenzie 2005. The participants conducted the test twice, in the sports hall and on dry sand. The study included 20 students (male) from the Medical University of Varna aged 19-23, training volleyball and beach volleyball. From the obtained results, the following indicators have been calculated: speed, acceleration, strength, and power. The results show that sand surface reduces the participants’ speed by an average of 10.66% which, is more than 0,5m per second. The average value of accelerations of all participants on the sand is 21.65% lower than indoor values. The difference in the ratio of the average values of the calculated powers is nearly 33%. The ability of students to maintain anaerobic performance on the sand is 1/3 lower than indoors. The results show that training on the sand increases requirements for physical capacity. As a result, students’ efforts for the same action are significantly greater. In conclusion, it can be stated that the training process on sand could improve the physical capacity of athletes practicing all kinds of sports, including hard surfaces. This can be used when planning training activities for each type of sport, as well as for all age groups.
Article
Full-text available
Purpose: This study was a comparison of physiological responses and speed performance of repeated sprint ability (RSA) with the change of direction between running on parquet surface (PS) and sand surface (SS). Methods: In a crossover design, 12 team sport athletes (21.5 ± 0.8 years) have randomly performed six sprints at 0 degrees (straight line), 90 degrees, and 180 degrees (shuttle run) on PS and SS. The distance of RSA with a change of direction adjusted by using the formula compensate for the lost time during the change of direction. Maximum speed, average speed, percentage of speed decrement (%Dec), blood lactate ([La]b), oxygen uptake (VO2), ventilation (VE), carbon dioxide production (VCO2), and RPE were measured each testing. Results: There was no significant interaction effect of the surface by direction for every dependent variable (all, p > 0.05). There were significant effects of surface for maximum speed and average speed (all, p < 0.05); but not for [La]b, VO2, VCO2, VE, RPE, and %Dec (all, p > 0.05). Specifically, running on PS had significantly higher maximum speed and average speed than SS. The main effect of running all direction was significant for [La]b, VO2, VCo2, VE, maximum speed, and average speed (all, p < 0.05); but not for RPE (p > 0.05). Conclusion: Surface has affected on running speed; running on PS have a higher speed than SS, but the surface does not affect physiological responses. Running at the straight line has higher physiological responses than running with change direction.
Article
Purpose: The purpose of the present study was to investigate the use of sand as an alternative surface for training, injury prevention and rehabilitation interventions in English professional football. A Secondary aim was to explore the potential barriers to implementation. Materials and methods: All 92 teams from the male English professional football pyramid during the 2021-22 season were eligible to take part. A cross-sectional survey of the medical personnel (one per club) was conducted between June 2021 and December 2021 based on the RE-AIM framework. A total of 58 respondents (63% of all clubs) completed the survey. Results and conclusions: Only 18 (31%) of the clubs surveyed used sand-based interventions across the last 3 seasons. Respondents felt sand-based interventions would be effective at improving physiological gains (median 4, interquartile range [IQR] 4-5) and as part of injury prevention and rehabilitation strategies (4, IQR 3-4) but were indifferent in relation to its potential to improve sporting performance (3, IQR 3-4). Barriers to implementation of sand-based interventions within wider football were a lack of facilities, lack of awareness of its potential benefits, lack of high-quality evidence and the surface not being specific to the sport. Medical staff also did not perceive that coaches' positively viewed sand interventions as a training or injury management strategy.
Article
Full-text available
This study aimed to identify the most important variables of male and female beach handball workload demands and compare them by sex. A total of 92 elite Brazilian beach handball players (54 male: age 22.1 ± 2.6 years, height 1.8 ± 0.5 m, weight 77.6 ± 13.4 kg; and 38 female: age 24.4 ± 5.5 years, height 1.7 ± 0.5 m, weight 67.5 ± 6.5 kg) were analyzed in 24 official matches during a four-day congested tournament. From 250 variables measured by the inertial measurement unit, fourteen were extracted for analysis using Principal Component Analysis as selection criteria. Five Principal Components (PC) were extracted that explained 81.2–82.8% of total variance (overview of workload demands during beach handball). Specifically, 36.2–39.3% was explained by PC1 (DistanceExpl, Distance, Distance4–7 km/h, and Acc), 15–18% by PC2 (AccMax, Acc3–4 m/s, Dec4–3 m/s), 10.7–12.9% by PC3 (JumpsAvg Take-Off, JumpsAvg Landing and PLRT), 8–9.4% by PC4 (Distance > 18.1 km/h, SpeedMax), and 6.7–7.7% by PC5 (HRAvg and Step Balance). Sex-related differences were found in the PC distribution of variables, as well as in selected variables (HRAvg, Dec4–3 m/s, Acc3–4 m/s, JumpsAvg Take-Off, JumpsAvg Landing, AccMax, Distance, Distance4–7 km/h, Acc, SpeedMax) with higher values in male players (p < .05). In conclusion, the sex-related PC distribution and workload demands in beach handball should consider for training design and injury prevention programs.
Conference Paper
Soccer is an intermittent high-intensity activity requiring explosive strength and power production by the neuromuscular system. Plyometric training is recognized as an effective method for improving both sprinting and jumping ability through the stretch-shortening cycle. The aim of this study was to compare the effects of plyometric training on sand versus a grass surface on sprinting, jumping, agility, balance ability in soccer players. Sixteen adult soccer players volunteered in the study and were randomly assigned to a plyometric training group performed on sand (PS, n = 8) or on grass (PG, n = 8). Both groups performed 7 weeks of plyometric training on two separate weekly sessions lasting about 1.5 hour. Five-, 10- and 20-meters sprint test, Sargent test and standing long jump test, Illynois Agility test and Stork test were administered to assess sprinting, jumping, agility and balance ability, respectively. After 7 weeks of intervention results showed significative improvements in PS group for sprinting (p<.05), for standing long jump test (p<.05) and for balance (p<.05). Small but not significant differences were found for the other variables. A 7-week plyometric training performed on sand showed improvements on sprinting, jumping and balance respect to the same training performed on grass surface in adult soccer players.
Article
Full-text available
This study aimed to analyse the influence of the FIFA Quality PRO certification of artificial turf pitches on the physical, physiological performance and muscle damage in soccer players. Fifteen healthy male players (21.2 ± 1.4 years; 178.2 ± 4.3 cm; 79.1 ± 8.3 kg) from a university football team were selected to participate in the research. Mechanical properties related to surface–player interaction were assessed on the two surfaces selected for this study. A randomized design was used and the players performed the Ball-sport Endurance and Sprint Test (BEAST90) on the different artificial turf fields. Average time of the 20 m sprints was longer on the FIFA Quality Pro surface than on the non-certified pitch (+0.13 s; p<0.05; CI95%: -0.01 to 0.27; ES: 0.305). The players’ perceived effort was higher in the first (+2.64; p<0.05; CI95%: 0.92 to 4.35; ES: 1,421) and the second half (+1.35; p<0.05; CI95%: -0.02 to 2.72; ES: 0.637) of the test on the FIFA Quality Pro field. Comparative analysis between surfaces showed no significant differences in the time spent in each of the heart rate zones and higher concentrations of CK (+196.58; p>0.05; CI95%: 66.54 to 326.61; ES: 1.645) were evidenced in the non-certified pitch surface. In response to a simulated match protocol, markers of post-exercise muscle damage may be reduced on accredited artificial turf fields. These insights can provide the opportunity to maximize the efficiency of training sessions and reduce the risk of injury during the season.
Article
Full-text available
Background: The aims of this study were: 1) to compare anthropometric and fitness variables of high-level beach handball players across Under-19 (U-19), Under-21 (U-21) and senior male categories, and between male and female senior players and; 2) to test the correlations among those measures. Methods: A total of 70 high-level players (53 male of different ages) were evaluated for 5-m acceleration, 15-m sprint, horizontal jump, handgrip strength, specific beach handball throwing velocities, and anthropometric variables. Differences between age groups were tested using ANOVA. Independent t-test was used to compare fitness variables between male and female elite athletes, and Pearson partial correlation coefficients were calculated between each of the fitness variables using BMI and age as covariates. SPSS Software was used, and the level of significance was set at 95%. Results: The U-21 athletes better performed on horizontal jump and 6-m throw than the U-19 athletes. Senior athletes showed better performance on horizontal jump than U-19 athletes (p≤.05). Positive correlation was seen for handgrip on dominant and non-dominant hands and 6-m throwing speed, and for handgrip on dominant hand and inflight velocity (p≤.05). Negative correlations were observed between horizontal jump and 5-m acceleration, and 15-m sprint (p≤.01 and p≤.05, respectively). Conclusions: Male athletes better performed than women in all the fitness tests. The study, for the first time, showed physical fitness comparisons between beach handball elite male athletes of different ages and between genders. These are key steps for coaches and athletes and may support future beach handball studies and practice.
Article
Full-text available
This single-blind, randomized controlled trial compared the effects of Thai dance exercise training on hard, soft, and sand surfaces on the functional outcomes of 120 community-dwelling older adults (40 subjects/group). The subjects were involved in a Thai dance exercise program on each surface, according to their groups, for 50 min/day, 3 days/week, for 6 weeks. The functional outcomes were assessed prior to training, at Week 3, and Week 6 after training. Subjects showed a significant improvement in all functional tests at 3 and 6 weeks after training, particularly in those who were trained on a sand surface and a soft surface (7–30% improvement, p < .05). The improvement was especially demonstrated in the complex and demanding motor activities after exercise on a soft and sand surface. Aside from attempting to modify training programs on a hard surface, the current findings suggest an alternative and cost-effective program to promote the levels of independence and safety that can be applied easily in clinical, home-based, and community settings.
Article
Full-text available
The objectives of this study were to determine the results of the analysis of single and double outdoor badminton men's matches and to determine the relationship between technical and tactical aspects in a study organized by the BWF (Badminton Word Federation), on a sand surface. Twenty men's singles matches were recorded using video cameras and analysed with a Dartfish video analysis software package. Along with this, percentages of use of technical elements were analysed by comparing the different modalities. For the single format Lob, Clear, Drop, Smash, Drive were used, different from the double format that used Lob, Clear, Drop, Smash, Drive. The study confirmed the applicability of computerized notation analysis to determine the characteristics of Outdoor Badminton on sand.
Article
Full-text available
The ˙VO2-power regression and O2 demand predicted for a supra-˙VO2peak intensity (i.e., 432 W) were determined in seven well-trained male cyclists (mean ± SD: ˙VO2peak = 5.29± 0.51 l·min⁻¹), using five incremental exercise protocols. These protocols were either continuous (CON) or discontinuous(DISCON), and comprised five to eight work bouts ranging in intensity between 40% and 85% ˙VO2peak; the work bouts differed in duration (4-15 min), and the ˙VO2 was measured during the 4th minute (CON4, DISCON4), from min 4 to 6 (DISCON6), 8 to 10 (DISCON10), or 13 to 15(DISCON15) of each work bout. The y-intercepts of the ˙VO2-power regressions were not different (P > 0.05), whereas the slope was higher (P ≤ 0.01) when determined using DISCON10 (12.7 ± 0.9 ml·min⁻¹·W⁻¹) and DISCON15 (12.5 ± 0.9 ml·min⁻¹·W⁻¹) compared with DISCON6 (12.2 ± 1.0 ml·min⁻¹·W⁻¹), DISCON4 (11.6 ± 1.1 ml·min⁻¹·W⁻¹) or CON4 (11.9 ± 0.7 ml·min⁻¹·W⁻¹). The O2 demand (at 432 W) was also higher (P ≤ 0.01) for DISCON10 (6.05 ± 0.29 l·min⁻¹) and DISCON15 (6.05 ± 0.28 l·min⁻¹) compared with DISCON6 (5.88 ± 0.31 l·min⁻¹), DISCON4(5.70 ± 0.31 l·min⁻¹) and CON4 (5.82 ± 0.25 l·min⁻¹). This demonstrates that the O2 demand predicted for high power outputs depends on the incremental protocol used.
Article
Full-text available
When mammals run, the overall musculoskeletal system behaves as a single linear "leg spring". We used force platform and kinematic measurements to determine whether leg spring stiffness (k(leg)) is adjusted to accommodate changes in surface stiffness (ksurf) when humans hoop in place, a good experimental model for examining adjustments to k(leg) in bouncing gaits. We found that k(leg) was greatly increased to accommodate surfaces of lower stiffnesses. The series combination of k(leg) and ksurf [total stiffness (ktot)] was independent of ksurf at a given hopping frequency. For example, when humans hopped at a frequency of 2 Hz, they tripled their k(leg) on the least stiff surface (ksurf = 26.1 kN/m; k(leg) = 53.3 kN/m) compared with the most stiff surface (ksurf = 35,000 kN/m; k(leg) = 17.8 kN/m). Values for ktot were not significantly different on the least stiff surface (16.7 kN/m) and the most stiff surface (17.8 kN/m). Because of the k(leg) adjustment, many aspects of the hopping mechanics (e.g., ground-contact time and center of mass vertical displacement) remained remarkably similar despite a > 1,000-fold change in ksurf. This study provides insight into how k(leg) adjustments can allow similar locomotion mechanics on the variety of terrains encountered by runners in the natural world.
Article
Full-text available
Oxygen uptake (VO2) at steady state, heart rate and perceived exertion were determined on nine subjects (six men and three women) while walking (3-7 km.h-1) or running (7-14 km.h-1) on sand or on a firm surface. The women performed the walking tests only. The energy cost of locomotion per unit of distance (C) was then calculated from the ratio of VO2 to speed and expressed in J.kg-1.m-1 assuming an energy equivalent of 20.9 J.ml O2-1. At the highest speeds C was adjusted for the measured lactate contribution (which ranged from approximately 2% to approximately 11% of the total). It was found that, when walking on sand, C increased linearly with speed from 3.1 J.kg-1.m-1 at 3 km.h-1 to 5.5 J.kg-1.m-1 at 7 km.h-1, whereas on a firm surface C attained a minimum of 2.3 J.kg-1.m-1 at 4.5 km.h-1 being greater at lower or higher speeds. On average, when walking at speeds greater than 3 km.h-1, C was about 1.8 times greater on sand than on compact terrain. When running on sand C was approximately independent of the speed, amounting to 5.3 J.kg-1.m-1, i.e. about 1.2 times greater than on compact terrain. These findings could be attributed to a reduced recovery of potential and kinetic energy at each stride when walking on sand (approximately 45% to be compared to approximately 65% on a firm surface) and to a reduced recovery of elastic energy when running on sand.
Article
Full-text available
Twelve experienced male weight lifters of varying ability completed a series of bench press lifts at 95% of maximum. These lifts included a rebound bench press, which was performed without a delay between the downward and upward components of the lift, a bench press performed without a downward phase, and two bench press movements performed with various pause periods imposed between the downward and upward phases of the lift. Force and cinematographic data were collected during each lift. The augmentation to performance derived from prior stretch was observed to decay as a function of the pause duration. This relationship was accurately described (P less than 0.01) by a negative exponential equation with a half-life of 0.85 s. The nature of this decay is discussed with reference to the implications for stretch-shorten cycle movements that are performed with a period of pause between the eccentric and concentric phases and for stretch-shorten cycle research paradigms.
Article
Full-text available
Oxygen consumption (VO2) and blood lactate concentration were determined during constant-speed track running on 16 runners of intermediate level competing in middle distances (0.8-5.0 km). The energy cost of track running per unit distance (Cr) was then obtained from the ratio of steady-state VO2, corrected for lactate production, to speed; it was found to be independent of speed, its overall mean being 3.72 +/- 0.24 J.kg-1 x m-1 (n = 58; 1 ml O2 = 20.9 J). Maximal VO2 (VO2max) was also measured on the same subjects. Theoretical record times were then calculated for each distance and subject and compared with actual seasonal best performances as follows. The maximal metabolic power (Er max) a subject can maintain in running is a known function of VO2max and maximal anaerobic capacity and of the effort duration to exhaustion (te). Er max was then calculated as a function of te from VO2max, assuming a standard value for maximal anaerobic capacity. The metabolic power requirement (Er) necessary to cover a given distance (d) was calculated as a function of performance time (t) from the product Crdt-1 = Er. The time values that solve the equality Er max(te) = Er(t), assumed to yield the theoretical best t, were obtained by an iterative procedure for any given subject and distance and compared with actual records.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Full-text available
Muscular exercise requires transitions to and from metabolic rates often exceeding an order of magnitude above resting and places prodigious demands on the oxidative machinery and O 2-transport pathway. The science of kinetics seeks to characterize the dynamic profiles of the respiratory, cardiovascular, and muscular systems and their integration to resolve the essential control mechanisms of muscle energetics and oxidative function: a goal not feasible using the steady-state response. Essential features of the O 2 uptake (˙ V O 2) kinetics response are highly conserved across the animal kingdom. For a given metabolic demand, fast ˙ V O 2 kinetics mandates a smaller O 2 deficit, less substrate-level phosphorylation and high exercise tolerance. By the same token, slow ˙ V O 2 kinetics incurs a high O 2 deficit, presents a greater challenge to homeostasis and presages poor exercise tolerance. Compelling evidence supports that, in healthy individuals walking, running, or cycling upright, ˙ V O 2 kinetics control resides within the exercising muscle(s) and is therefore not dependent upon, or limited by, upstream O 2-transport systems. However, disease, aging, and other imposed constraints may redistribute ˙ V O 2 kinetics control more prox-imally within the O 2-transport system. Greater understanding of ˙ V O 2 kinetics control and, in particular, its relation to the plasticity of the O 2-transport/utilization system is considered important for improving the human condition, not just in athletic populations, but crucially for patients suffering from pathologically slowed ˙ V O 2 kinetics as well as the burgeoning elderly population. C 2012 American Physiological Society. Compr Physiol 2:933-996, 2012.
Article
Full-text available
The VO2-power regression and O2 demand predicted for a supra-VO2peak intensity (i.e., 432 W) were determined in seven well-trained male cyclists (mean +/- SD: VO2peak = 5.29 +/- 0.51 l.min-1), using five incremental exercise protocols. These protocols were either continuous (CON) or discontinuous (DISCON), and comprised five to eight work bouts ranging in intensity between 40% and 85% VO2peak; the work bouts differed in duration (4-15 min), and the VO2 was measured during the 4th minute (CON4, DISCON4), from min 4 to 6 (DISCON6), 8 to 10 (DISCON10), or 13 to 15 (DISCON15) of each work bout. The y-intercepts of the VO2-power regressions were not different (P > 0.05), whereas the slope was higher (P < or = 0.01) when determined using DISCON10 (12.7 +/- 0.9 ml.min-1.W-1) and DISCON15 (12.5 +/- 0.9 ml.min-1.W-1) compared with DISCON6 (12.2 +/- 1.0 ml.min-1.W-1), DISCON4 (11.6 +/- 1.1 ml.min-1.W-1) or CON4 (11.9 +/- 0.7 ml.min-1.W-1). The O2 demand (at 432 W) was also higher (P < or = 0.01) for DISCON10 (6.05 +/- 0.29 l.min-1) and DISCON15 (6.05 +/- 0.28 l.min-1) compared with DISCON6 (5.88 +/- 0.31 l.min-1), DISCON4 (5.70 +/- 0.31 l.min-1) and CON4 (5.82 +/- 0.25 l.min-1). This demonstrates that the O2 demand predicted for high power outputs depends on the incremental protocol used.
Article
Full-text available
Moving about in nature often involves walking or running on a soft yielding substratum such as sand, which has a profound effect on the mechanics and energetics of locomotion. Force platform and cinematographic analyses were used to determine the mechanical work performed by human subjects during walking and running on sand and on a hard surface. Oxygen consumption was used to determine the energetic cost of walking and running under the same conditions. Walking on sand requires 1.6-2.5 times more mechanical work than does walking on a hard surface at the same speed. In contrast, running on sand requires only 1.15 times more mechanical work than does running on a hard surface at the same speed. Walking on sand requires 2.1-2.7 times more energy expenditure than does walking on a hard surface at the same speed; while running on sand requires 1.6 times more energy expenditure than does running on a hard surface. The increase in energy cost is due primarily to two effects: the mechanical work done on the sand, and a decrease in the efficiency of positive work done by the muscles and tendons.
Article
Full-text available
Previous studies have suggested that generating vertical force on the ground to support body weight (BWt) is the major determinant of the metabolic cost of running. Because horizontal forces exerted on the ground are often an order of magnitude smaller than vertical forces, some have reasoned that they have negligible cost. Using applied horizontal forces (AHF; negative is impeding, positive is aiding) equal to -6, -3, 0, +3, +6, +9, +12, and +15% of BWt, we estimated the cost of generating horizontal forces while subjects were running at 3.3 m/s. We measured rates of oxygen consumption (VO2) for eight subjects. We then used a force-measuring treadmill to measure ground reaction forces from another eight subjects. With an AHF of -6% BWt, VO2 increased 30% compared with normal running, presumably because of the extra work involved. With an AHF of +15% BWt, the subjects exerted approximately 70% less propulsive impulse and exhibited a 33% reduction in VO2. Our data suggest that generating horizontal propulsive forces constitutes more than one-third of the total metabolic cost of normal running.
Article
Full-text available
The energy cost of kayaking per unit distance (C(k), kJ x m(-1)) was assessed in eight middle- to high-class athletes (three males and five females; 45-76 kg body mass; 1.50-1.88 m height; 15-32 years of age) at submaximal and maximal speeds. At submaximal speeds, C(k) was measured by dividing the steady-state oxygen consumption (VO(2), l x s(-1)) by the speed (v, m x s(-1)), assuming an energy equivalent of 20.9 kJ x l O(-1)(2). At maximal speeds, C(k) was calculated from the ratio of the total metabolic energy expenditure (E, kJ) to the distance (d, m). E was assumed to be the sum of three terms, as originally proposed by Wilkie (1980): E = AnS + alphaVO(2max) x t-alphaVO(2max) x tau(1-e(-t x tau(-1))), were alpha is the energy equivalent of O(2) (20.9 kJ x l O(2)(-1)), tau is the time constant with which VO(2max) is attained at the onset of exercise at the muscular level, AnS is the amount of energy derived from anaerobic energy utilization, t is the performance time, and VO(2max) is the net maximal VO(2). Individual VO(2max) was obtained from the VO(2) measured during the last minute of the 1000-m or 2000-m maximal run. The average metabolic power output (E, kW) amounted to 141% and 102% of the individual maximal aerobic power (VO(2max)) from the shortest (250 m) to the longest (2000 m) distance, respectively. The average (SD) power provided by oxidative processes increased with the distance covered [from 0.64 (0.14) kW at 250 m to 1.02 (0.31) kW at 2000 m], whereas that provided by anaerobic sources showed the opposite trend. The net C(k) was a continuous power function of the speed over the entire range of velocities from 2.88 to 4.45 m x s(-1): C(k) = 0.02 x v(2.26) (r = 0.937, n = 32).
Article
The purpose of this investigation was to examine day-to-day variations in metabolic measurements during submaximal exercise. Ten male subjects (five cyclists, five runners) randomly performed four cycling (CYC) and four running (RUN) trials. CYC trials were conducted on a bicycle ergometer at 100 W, 150 W, and 200 W; and RUN trials at treadmill velocities of 170, 200, and 230 m/min. Oxygen consumption ([Vdot]O 2) and minute ventilation ([Vdot]E) were recorded each minute by a computer-based system. Blood lactic acid (HLA) was sampled from an antecubital vein at 3-min post exercise. No significant differences (p > .05) were found between cyclists and runners in [Vdot]O 2, [Vdot]E, or HLA at any workload. The mean coefficients of total variation (CVt = SD/[Xdot] · 100%) for [Vdot]O 2 were 4.42% (CYC) and 3.80% (RUN); mean CVt for [Vdot]E were 3.86% (CYC) and 4.82% (RUN); mean CVt for HLA were 13.4% (CYC) and 16.3% (RUN). Significant day-to-day differences (p < .05) were found in [Vdot]O 2 of cyclists during CYC and RUN, [Vdot]O 2 of runners while CYC and RUN, and [Vdot]E of cyclists during RUN. No significant day-to-day differences were observed for HLA. These data demonstrate the importance of considering [Vdot]O 2, [Vdot]E, and HLA variability in reporting the results of experimental protocols.
Article
For constant-load, heavy exercise (i.e., above the lactate threshold (TLac.)), a slow component of oxygen uptake ([latin capital V with dot above]O2) is observed. Endurance training reduces the magnitude of the slow component and, hence, end-exercise [latin capital V with dot above]O2. Reductions in exercise [latin capital V with dot above]O2 have been reported after 7-8 wk of training; unpublished observations suggest that the [latin capital V with dot above]O2 slow component may be attenuated after just 2 wk of training. A minimum training intensity for eliciting reductions in constant-load exercise [latin capital V with dot above]O2 has not been established; however, in the elderly, training at an intensity below TLac resulted in similar reductions in exercise [latin capital V with dot above]O2 as did training above TLac. Mechanisms responsible for the reduced slow component of [latin capital V with dot above]O2 after training remain to be firmly established. Evidence both for and against blood lactate concentration ([L-]) as a mediator of the slow component has been published; high correlations between [L-] and the slow component, and between the training-induced reductions in these variables, appear to be more coincidental than causal. Decreased pulmonary ventilation after training may account for between 14% and 30% of the reduction in the slow component of [latin capital V with dot above]O2. Epinephrine infusion does not augment exercise [latin capital V with dot above]O2, nor does [beta]-adrenergic blockade diminish the magnitude of the slow component of [latin capital V with dot above]O2. (C)1994The American College of Sports Medicine
Article
Characterizing oxygen uptake ([latin capital V with dot above]O2) kinetics yields valuable information regarding both a) the effectiveness of the coupling of O2 delivery to tissue metabolic demands, and b) the ability of the muscle itself to utilize O2 for oxidative phosphorylation. During moderate exercise [latin capital V with dot above]O2 reaches a new steady state within 3 min in normal subjects, with little or no sustained rise in blood lactate. The steady state [latin capital V with dot above]O2 increases linearly with work rate. The time constant for [latin capital V with dot above]O2 in Phase 2 (after first 15-20 s) is constant across work intensities, and appears to reflect muscle oxygen utilization kinetics. However, when heavier exercise is performed, which elevates blood lactate throughout the exercise, the [latin capital V with dot above]O2 response becomes more complex. The predominant, Phase 2 response continues to rise exponentially with about the same time constant as for moderate exercise, and the amplitude continues to be linearly related to work rate. However, an additional, slowly developing rise in [latin capital V with dot above]O2 is also usually observed, beginning 100-200 s into exercise. This additional [latin capital V with dot above]O2 delays attainment of a steady state, increases the overall O2 "cost" of the exercise, and is statistically associated with the rate and magnitude of increase in blood lactate. Interestingly, in children, neither the slow component nor blood lactate rise as much during heavy exercise. (C)1994The American College of Sports Medicine
Article
A model of running is proposed in which the leg is represented as a rack-and-pinion element in series with a damped spring. The rack-and-pinion element emphasizes the role of descending commands, while the damped spring represents the dynamic properties of muscles and the position and the rate sensitivity of reflexes. This model is used to predict separately the effect of track compliance on step length and ground contact time. The predictions are compared with experiments in which athletes ran over tracks of controlled spring stiffness. A sharp spike in foot force up to 5 times body weight was found on hard surfaces, but this spike disappeared as the athletes ran on soft experimental tracks. Both ground contact time and step length increased on very compliant surfaces, leading to moderately reduced running speeds, but a range of track stiffness was discovered which actually enhances speed.
Article
The study of running economy has important performance implications for the long-distance runner and may provide insight into mechanisms underlying economical human locomotion. Physiological aspects of running economy discussed in this paper include intraindividual variability, body temperature, heart rate, ventilation, muscle fiber type, gender, air and wind resistance, altitude, fatigue, and training. The lack of consensus evident in the literature regarding many of these variables and their influence on economy supports the use of expanded sample sizes featuring both genders, standard testing conditions, and cross- and interdisciplinary approaches to help explain group economy differences observed in descriptive and experimental paradigms and to extend the generalizability of research findings.
Article
In order to investigate the reproducibility of maximum progressive exercise we studied 6 healthy volunteers twice a day for 3 nonconsecutive days. The average within-subject coefficients of variation for the maximal ventilatory and heart rate (HR) responses ranged from 3.8% for HR to 12% for minute ventilation (Ve) and anaerobic threshold. Three-way analysis of variance revealed no significant variations in exercise parameters for the group as a whole except for the carbon dioxide output (VCO2) and respiratory exchange ratio (R) which was significantly greater in the afternoon (p less than 0.05). This was attributed to dietary effects of carbohydrate loading upon VCO2 and was associated in 1 subject with a significant increase in Ve (p less than 0.01). In another subject, morning values of Ve were consistently and significantly (p less than 0.05) greater than the afternoon values which could only be attributed to increased effort as indicated by an increased oxygen uptake. Tests of resting pulmonary mechanics (FEV1, FVC, FRC, RAW) measured before each exercise procedure showed no significant diurnal or day-to-day variations. Results indicate that while the maximal responses to progressive exercise are generally reproducible and the first exercise procedure can usually be considered representative, diurnal variations in R, VCO2 and Ve may occur which can be best avoided on repeated testing by exercising subjects at a standardized time of day.
Article
The energy cost of the forms of locomotion discussed throughout this article is summarized in Table 9. This table, as well as the preceding sections of this article, are designed to provide a rather comprehensive and simple set of information for potential readers: medical doctors, who should be able to prescribe to their patients (obese, hypertensive, cardiac, etc.) the correct amount and type of exercise, thus making use of exercise as of any other drug, of which it is imperative to know posology and contraindications; athletes, trainers, and sportsmen in general, who should gear correctly their diet to the type and amount of physical exercise; physical educators, who should be aware of the specific characteristics of the exercise modes they propose to their pupils, as a function of their sex, age, and athletic capacity. However, besides these practical applications, the notions discussed throughout this article bear also a more general interest. Indeed, they allow a better understanding of the motion of man, that is, of the only machine, which besides moving about, also tries to understand how he does it.
Article
An important determinant of the mechanics of running is the effective vertical stiffness of the body. This stiffness increases with running speed. At any one speed, the stiffness may be reduced in a controlled fashion by running with the knees bent more than usual. In a series of experiments, subjects ran in both normal and flexed postures on a treadmill. In other experiments, they ran down a runway and over a force platform. Results show that running with the knees bent reduces the effective vertical stiffness and diminishes the transmission of mechanical shock from the foot to the skull but requires an increase of as much as 50% in the rate of O2 consumption. A new dimensionless parameter (u omega 0/g) is introduced to distinguish between hard and soft running modes. Here, omega 0 is the natural frequency of a mass-spring system representing the body, g is gravity, and u is the vertical landing velocity. In normal running, this parameter is near unity, but in deep-flexed running, where the aerial phase of the stride cycle almost disappears, u omega 0/g approaches zero.
Article
The relationships between biocmechanical aspects of distance running, running economy (VO2 submax), and performance were investigated. A variety of biomechanical measures for 31 subjects running at 3.6 m/s was obtained, including three-dimensional angular and translational kinematics, ground reaction forces and center of pressure patterns, mechanical power, and anthropometric measures. Physiological measures obtained included maximal and submaximal O2 consumption, muscle fiber composition, and measures of the ability to store and return elastic energy during knee bends. A subset of 16 runners was also evaluated in relation to performance in a 10-km run. Biomechanical variables were identified which showed significant differences or consistent trends between groups separated on the basis of VO2 submax, establishing the importance of biomechanical influences on running economy. It appears that no single variable or small subset of variables can explain differences in economy between individuals but rather that economy is related to a weighted sum of the influences of many variables.
Article
Maximal O2 consumption (V˙O2max\dot V_{O_{_2 max} } and energy cost of running per unit distance (C) were determined on the treadmill in 36 male amateur runners (17 to 52 years) who had taken part in a marathon (42.195 km) or semi-marathon (21 km), their performance times varying from 149 to 226 and from 84 to 131 min, respectively.V˙O2max\dot V_{O_{_2 max} } was significantly (2p<0.001) greater in the marathon runners (60.6 vs 52.1 ml · kg−1 · min−1) whileC was the same in both groups (0.179±0.017, S.D., mlO2 · kg−1 · m−1 above resting), and independent of treadmill speed. It can be shown that the maximal theoretical speed in endurance running (vEND) is set byV˙O2max\dot V_{O_{_2 max} } , its maximal sustainable fraction (F), andC, as described by:vEND=F ·V˙O2max\dot V_{O_{_2 max} } ·C −1. SinceF was estimated from the individual time of performance,vEND could be calculated. The average speed of performance (vMIG) andvEND (m · s−1) were found to be linearly correlated:vMIG=1.12+0.64vEND (r 2=0.72;n=36). The variability ofvMIG explained byvEND, as measured byr 2, is greater than that calculated from any one regression betweenvMIG andV˙O2max\dot V_{O_{_2 max} } (r 2=0.51),F ·V˙O2max\dot V_{O_{_2 max} } (r 2=0.58), orV˙O2max\dot V_{O_{_2 max} } ·C −1 (r 2=0.63). The mean ratio of observed (vMIG) to theoretical (vEND) speeds amounted to 0.947±0.076 and increased to 0.978±0.079 (±S.D.;n=36) when the effects of air resistance were taken into account. It is concluded thatvEND=F ·V˙O2max\dot V_{O_{_2 max} } ·C −1 is a satisfactory quantitative description of the energetics of endurance running.
Article
The physiological energy expenditure involved in common activities such as running, walking, or cycling can be influenced by a variety of biomechanical factors. In evaluating changes in mechanical energy in order to derive a measure of mechanical power which is more directly related to metabolic energy cost, it is necessary to be able to identify the source of these changes. Factors such as concentric and eccentric muscular contractions, transfer of energy, elastic storage and reuse of energy, and joint range of motion limitations can all change the mechanical energy of a segment, but each involves a different metabolic energy expenditure. While a number of computational methods have been suggested for the calculation of mechanical power, each incorporates a different set of assumptions involving the factors just mentioned, and widely varying results for mechanical power have been obtained. The lack of definitive information concerning the relationship between mechanical and physiological energy changes limits the accuracy, meaningfulness, and usefulness of measures of mechanical power and muscular efficiency.
Article
3 subjects ran on the treadmill (10 km/h) against varying horizontal impeding forces. One subject was further studied during the same kind of walking and bicycling on the treadmill, and during work consisting in lowering and lifting the body by flexing and extending the legs from a standing or sitting position at varying frequencies, with or without rebound in the deepest position. Workpower (W kcal/min), and the corresponding steady state metabolic rate (E kcal/min, Douglas bag method) were measured. Apparent efficiency (N) was calculated as Δẁ/ΔÈ× 100 %. During load running N was 53.8, 37.6 and 41.2 %, respectively, in the 3 subjects. In the subject more extensively studied N was: running 53.8, walking 32.3, bicycling 25.1, knee-flexions (deep or half) with rebound 39.4 or 41.0, without rebound 26.1 or 21.9 %. These variations in N % were explained in accordance with the possibilities for re-using the energy, absorbed and stored in the muscles as elastic energy during a phase of negative exercise, in a subsequent phase of positive exercise. The condition of this is that the positive phase follows immediately after the negative. A calculation showed that during running 35–53 % of the energy absorbed during the negative phase was re-used. Corresponding figures for walking and rebounding knee-extensions were 23 % and 34 %, respectively, while in bicycling and knee-extensions without rebound all of the negative work degenerated into heat.
Article
1. The relation of V̇ O 2 and speed was measured on seven athletes running on a cinder track and an all‐weather track. The results were compared with similar observations on four athletes running on a treadmill. 2. In treadmill running the relation was linear and the zero intercept coincided with resting V̇ O 2 . 3. In track running the relation was curvilinear, but was adequately represented by a linear regression over a range of speeds extending from 8·0 km/hr (2·2 m/sec) to 21·5 km/hr (6·0 m/sec). The slope of this line was substantially steeper than the regression line slope for treadmill running. 4. The influence of air resistance in running was estimated from measurements of V̇ O 2 on a subject running on a treadmill at constant speed against wind of varying velocity. 5. The extra O 2 intake (Δ V̇ O 2 ) associated with wind increased as the square of wind velocity. If wind velocity and running velocity are equal, as in running on a track in calm air, Δ V̇ O 2 will increase as the cube of velocity. 6. It was estimated that the energy cost of overcoming air resistance in track running is about 8% of total energy cost at 21·5 km/hr (5000 m races) and 16% for sprinting 100 m in 10·0 sec.