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A Self-Paced Intermittent Protocol on a Non-Motorised Treadmill: A Reliable Alternative to Assessing Team-Sport Running Performance
Abstract
This study assessed the reliability of a 'self-paced' 30-min, team-sport running protocol on a Woodway Curve 3.0 non-motorised treadmill (NMT). Ten male team-sport athletes (20.3 ± 1.2 y, 74.4 ± 9.7 kg, VO2peak 57.1 ± 4.5 ml·kg(-1)·min(-1)) attended five sessions (VO2peak testing + familiarisation; four reliability trials). The 30-min protocol consisted of three identical 10-min activity blocks, with visual and audible commands directing locomotor activity; however, actual speeds were self-selected by participants. Reliability of variables was estimated using typical error ± 90% confidence limits expressed as a percentage [coefficient of variation (CV)] and intraclass correlation coefficient. The smallest worthwhile change (SWC) was calculated as 0.2 × between participant standard deviation. Peak/mean speed and distance variables assessed across the 30-min protocol exhibited a CV < 5%, and < 6% for each 10-min activity block. All power variables exhibited a CV < 7.5%, except walking (CV 8.3-10.1%). The most reliable variables were maximum and mean sprint speed (CV < 2%). All variables produced a CV% greater than the SWC. A self-paced, team-sport running protocol performed on a NMT produces reliable speed/distance and power data. Importantly, a single familiarisation session allowed for adequate test-retest reliability. The self-paced design provides an ecologically-valid alternative to externally-paced team-sport running simulations. Key pointsSelf-paced team-sport running protocols on a curved NMT that closely match the locomotor demands of competition deliver reliable test-retest measures of speed, distance and power.Such protocols may be sensitive to changes in running profile following an intervention that may not be detectable during externally-paced protocols.One familiarisation session is adequate to ensure test-retest reliability.
... Although the sprint task is favorable to replicate movement demands in sports, conducting sprint tests on a NMT may introduce variability across separate trials, given the distinct biomechanical movement patterns induced by the tethered system (Montgomery et al., 2016). Thus, familiarization trials are commonly incorporated to minimize learning effects with improved performance and reliability reported across a greater number of familiarization trials (Hopker et al., 2009;McLain et al., 2015;Tofari et al., 2015). However, most studies have examined the reliability of NMT sprint performance across separate days, and rarely within the same testing session. ...
... and 2 nd and 3 rd (4.8-21.1%) testing days (Hopker et al., 2009;Tofari et al., 2015). Based upon our findings and those of others (Hopker et al., 2009;Tofari et al., 2015), we would recommend incorporating at least two familiarization sessions, in conjunction with two maximal trials during each testing session to optimize reliable short, sprint performance protocols on a NMT for future interventions. ...
... testing days (Hopker et al., 2009;Tofari et al., 2015). Based upon our findings and those of others (Hopker et al., 2009;Tofari et al., 2015), we would recommend incorporating at least two familiarization sessions, in conjunction with two maximal trials during each testing session to optimize reliable short, sprint performance protocols on a NMT for future interventions. ...
This study examined the intra-session reliability of sprint performance on a non-motorized treadmill amongst healthy, active male and female adults. One hundred and twenty participants (males n = 77; females n = 45) completed two familiarization sessions, followed by a third session that consisted of three trials (T1, T2, T3) of maximal sprints (4-s), interspersed by three minutes of recovery. Combining males and females exhibited moderate-to-excellent test-retest reliability (intra-class correlation coefficient, ICC), minimal measurement error (coefficient of variation, CV) and trivial differences between trials (effect size, ES) for speed, power, total work and acceleration (ICC = 0.82–0.98, CV = 1.31–8.45%, ES = 0.01–0.22). The measurement error was improved between comparisons of T1 vs. T2 (CV = 1.62–8.45%, ES = 0.12–0.22) to T2 vs. T3 (CV = 1.31–6.56%, ES = 0.01–0.07) and better for females (CV = 1.26–7.94%, ES = 0.001–0.26) than males (CV = 1.33–8.53%, ES = 0.06–0.31). The current study demonstrated moderate-to-excellent reliability and good-moderate measurement error during a 4-s sprint on a non-motorized treadmill. However, sex had a substantial impact with females exhibiting better values. Practitioners should employ at least two separate trials within a session, in addition to multiple familiarization sessions, to achieve reliable non-motorized treadmill sprint performances.
... More research is warranted to gain a clear understanding of the benefit of using a mixed-method pre-cooling protocol to investigate the role of lowering core temperature and T sk on intermittent exercise performance. Given that team sports are inherently self-paced, nonmotorised treadmills (NMT) have allowed the development of internally paced performance tests, offering a potentially more ecologically valid assessment tool in comparison to externally paced protocols (Tofari et al. 2014). As such, we have adopted this approach to assess team-sport-specific running performance in the heat following cooling. ...
... With at least 24-h separating the V O 2max test, to ensure adequate test-retest reliability (Tofari et al. 2014), participants returned to the laboratory ( ~ 19 °C, 45% RH) to familiarise themselves with the intermittent protocol on the nonmotorised Treadmill (Woodway Curve 3.0TM; Woodway, Inc., Waukesha, Wisconsin, USA). ...
... A 46-min modified protocol derived from the 30-min self-paced intermitted protocol, validated by Tofari et al. 2014 was employed, which has a coefficient of variation (with 90% confidence intervals) from a test-retest (n = 3) of 2.9% (3.8-4.1) for total distance covered (km), 4.6% (3.3-8.1) for peak speed (km/h) and 3.8% (0.96-1.1) for sprint distance (km). ...
Purpose
To investigate the effects of lowering core (Tgi) and mean skin temperature (Tsk) concomitantly and independently on self-paced intermittent running in the heat.
Methods
10 males (30.5 ± 5.8 years, 73.2 ± 14.5 kg, 176.9 ± 8.0 cm, 56.2 ± 6.6 ml/kg/min) completed four randomised 46-min self-paced intermittent protocols on a non-motorised treadmill in 34.4 ± 1.4 °C, 36.3 ± 4.6% relative humidity. 30-min prior to exercise, participants were cooled via either ice slurry ingestion (INT); a cooling garment (EXT); mixed-cooling (ice slurry and cooling garment concurrently) (MIX); or no-cooling (CON).
Results
At the end of pre-cooling and the start of exercise Tgi were lower during MIX (36.11 ± 1.3 °C) compared to CON (37.6 ± 0.5 °C) and EXT (36.9 ± 0.5 °C, p < 0.05). Throughout pre-cooling Tsk and thermal sensation were lower in MIX compared to CON and INT, but not EXT (p < 0.05). The reductions in thermophysiological responses diminished within 10–20 min of exercise. Despite lowering Tgi, Tsk, body temperature (Tb), and thermal sensation prior to exercise, the distances covered were similar (CON: 6.69 ± 1.08 km, INT: 6.96 ± 0.81 km, EXT: 6.76 ± 0.65 km, MIX 6.87 ± 0.70 km) (p > 0.05). Peak sprint speeds were also similar between conditions (CON: 25.6 ± 4.48 km/h, INT: 25.4 ± 3.6 km/h, EXT: 26.0 ± 4.94 km/h, MIX: 25.6 ± 3.58 km/h) (p > 0.05). Blood lactate, heart rate and RPE were similar between conditions (p > 0.05).
Conclusion
Lowering Tgi and Tsk prior to self-paced intermittent exercise did not improve sprint, or submaximal running performance.
... Compared to a motorized treadmill (MOT), where belt speed is controlled by an external motor, NMTs are participant driven and provide a closer experience to overground locomotion by allowing rapid acceleration and deceleration, step-to-step gait variability and internal pacing (De Witt et al., 2009;Fullenkamp et al., 2015;Stevens et al., 2015). A number of recent studies have shown NMTs to be a practical, valid, and reliable tool for assessing a range of clinical (Janaudis-Ferreira et al., 2010) and sportspecific movement patterns; including sprinting (Gonzalez et al., 2013;Mangine et al., 2014), endurance (Davies et al., 1984;Stevens et al., 2014Stevens et al., , 2015Morgan et al., 2016;Waldman et al., 2017) and team-sport running (Sirotic and Coutts, 2008;Aldous et al., 2014;Tofari et al., 2015). Consequently, the last few years has seen a marked increase in the use of NMTs in laboratory based interventions investigating the impact of environmental factors (Aldous et al., 2016;Gerrett et al., 2016;Sweeting et al., 2017;Stevens et al., 2017a,b), warm up (van den Tillaar et al., 2017), recovery (Pelka et al., 2017), fatigue (Tofari et al., 2017), and ergogenic aids (Sear et al., 2010;Coull et al., 2015) on performance. ...
... In the first session, maximal aerobic power (VO 2peak ) was determined and subjects were familiarized with the strength testing protocols and running on the cNMT. In the second session, subjects performed the strength tests and completed a second familiarization on the cNMT to ensure data reliability (Gonzalez et al., 2013;Tofari et al., 2015). Familiarization trials on the cNMT consisted of running for 2 min at each of the required speeds. ...
... A secondary aim of the study was to examine the reliability of cardiometabolic data collected when running at different speeds on the cNMT. Participants completed two familiarization sessions to ensure they could maintain the correct pacing and run confidently on the cNMT without the need for handrail support (Sirotic and Coutts, 2008;Mangine et al., 2014;Tofari et al., 2015). Using the visual pacer, subjects were able to reliably maintain cNMT belt speed within 0.02 m.s −1 of the target speed, a similar accuracy to that previously reported for walking and jogging on a cNMT (Smoliga et al., 2015). ...
The aim of this study was to compare the cardiometabolic demands of running on a curved non-motorized treadmill (cNMT) with overground (OVR) and motorized treadmill (MOT) running. Fourteen trained male (n = 7) and female (n = 7) runners (V·O2peak 56.6 ± 4.0 mL.kg⁻¹.min⁻¹) participated in the study. Each experimental session consisted of 5 × 6-min bouts of running at progressively higher speeds, separated by 6-min rest (females 9–15 km.h⁻¹; males 10.5–16.5 km.h⁻¹). Oxygen consumption (V·O2) and heart rate (HR) during the last 2 min of each bout were measured using a portable metabolic cart. Running at a set speed on the cNMT required a higher percentage of V·O2peak than OVR (mean ± 90% CI, 22 ± 6%; ES ± 90% CI, 1.87 ± 0.15) and MOT (16 ± 6%; ES 1.50 ± 0.15) running. Similarly, HR during the cNMT was higher compared to OVR (25 ± 9 beats.min⁻¹, ES 1.23 ± 0.14) and MOT (22 ± 9 beats.min⁻¹, ES 1.35 ± 0.13) trials. The decline in running economy observed during the cNMT trial was negatively related to body mass (R² 0.493, P = 0.01), indicating lighter runners were required to work at a higher relative intensity to overcome treadmill belt resistance. These data demonstrate the higher cardiometabolic demand associated with running at a given speed on the cNMT. It is critical these differences are taken into account when prescribing training intensities on the cNMT or translating data from the laboratory to an athletic setting.
... Compared to a motorized treadmill (MOT), where belt speed is controlled by an external motor, NMTs are participant driven and provide a closer experience to overground locomotion by allowing rapid acceleration and deceleration, step-to-step gait variability and internal pacing (De Witt et al., 2009;Fullenkamp et al., 2015;Stevens et al., 2015). A number of recent studies have shown NMTs to be a practical, valid, and reliable tool for assessing a range of clinical (Janaudis-Ferreira et al., 2010) and sportspecific movement patterns; including sprinting (Gonzalez et al., 2013;Mangine et al., 2014), endurance (Davies et al., 1984;Stevens et al., 2014Stevens et al., , 2015Morgan et al., 2016;Waldman et al., 2017) and team-sport running (Sirotic and Coutts, 2008;Aldous et al., 2014;Tofari et al., 2015). Consequently, the last few years has seen a marked increase in the use of NMTs in laboratory based interventions investigating the impact of environmental factors (Aldous et al., 2016;Gerrett et al., 2016;Sweeting et al., 2017;Stevens et al., 2017a,b), warm up (van den Tillaar et al., 2017), recovery (Pelka et al., 2017), fatigue (Tofari et al., 2017), and ergogenic aids (Sear et al., 2010;Coull et al., 2015) on performance. ...
... In the first session, maximal aerobic power (VO 2peak ) was determined and subjects were familiarized with the strength testing protocols and running on the cNMT. In the second session, subjects performed the strength tests and completed a second familiarization on the cNMT to ensure data reliability (Gonzalez et al., 2013;Tofari et al., 2015). Familiarization trials on the cNMT consisted of running for 2 min at each of the required speeds. ...
... A secondary aim of the study was to examine the reliability of cardiometabolic data collected when running at different speeds on the cNMT. Participants completed two familiarization sessions to ensure they could maintain the correct pacing and run confidently on the cNMT without the need for handrail support (Sirotic and Coutts, 2008;Mangine et al., 2014;Tofari et al., 2015). Using the visual pacer, subjects were able to reliably maintain cNMT belt speed within 0.02 m.s −1 of the target speed, a similar accuracy to that previously reported for walking and jogging on a cNMT (Smoliga et al., 2015). ...
... When matched for exercise intensities, it was established that on the cNMT a comparable oxygen consumption (VȮ 2 ) and heart rate (HR) are achieved on running velocities up to 25% lower than those on the MT (6,8,10,12). Despite these differences, the cNMT is believed to be a reliable and valid piece of laboratory equipment to evaluate self-paced high-intensity interval training sessions, endurance, and (repeated) sprint performance (4,8,(10)(11)(12). ...
... The cNMT can be used to assess running performance in the laboratory and to perform "uphill" training sessions, when uphill training is geographically challenging or suboptimal weather conditions discourage outdoor training (4,8,(10)(11)(12). The findings of the current study can be used as a reference value by athletes and coaches in the planning of cNMT training sessions and amend running velocities accordingly. ...
Schoenmakers, PPJM, Crisell, JJ, and Reed, KE. Physiological and perceptual demands of running on a curved nonmotorized treadmill compared with running on a motorized treadmill set at different grades. J Strength Cond Res XX(X): 000-000, 2020-The current study compared the physiological and perceptual demands of running on a commercially available curved nonmotorized treadmill (cNMT) with different incline grades on a motorized treadmill (MT). Ten male team-sport athletes completed, after a familiarization session, a 6-minute run at a target velocity of 2.78 m·s on the cNMT (cNMTrun). The mean individual running velocity of cNMTrun was then used as warm-up and experimental running velocity in 3 subsequent visits, in which subjects ran for 6 minutes on the MT set at different grades (4, 6, or 8%). In all experimental trials (cNMTrun, 4MTrun, 6MTrun, and 8MTrun) and in the warm-up of the subjects' third visit (1MTrun), oxygen consumption (V[Combining Dot Above]O2) and heart rate (HR) were monitored, and ratings of perceived exertion (RPE) were obtained. The HR in cNMTrun was significantly higher compared with all MT trials. V[Combining Dot Above]O2 and RPE were significantly higher in cNMTrun compared with 1MTrun and 4MTrun, but not different from 6MTrun and 8MTrun. The relationship between V[Combining Dot Above]O2 and MT grades was highly linear (V[Combining Dot Above]O2 = 34.36 + 1.7 MT grade; r = 0.99), and using linear interpolation, the concave curved design of the cNMT was estimated to mimic a 6.9 ± 3% MT grade. On matched running velocities, V[Combining Dot Above]O2 and RPE responses while running on the cNMT are similar to a 6-8% MT grade. These findings can be used as a reference value by athletes and coaches in the planning of cNMT training sessions and amend running velocities accordingly. Future studies are needed to determine whether this estimate is similar for female runners, or those of a lower body mass.
... A previously reported team sport running protocol was then used to assess self-paced, sport-specific running performance (33). Briefly, this protocol involves subjects completing 30 minutes of self-paced, intermittent running on a nonmotorized treadmill (Woodway Curve 3.0., Woodway, USA). ...
... In the 2 weeks before the study, subjects underwent 2 familiarization sessions on the nonmotorized treadmill, where 20 minutes and 15 minutes of this protocol were completed, respectively. This protocol has previously been shown to be reliable after 1 familiarization session (33). In this study, the primary outcome variable measured during the team sport protocol was total distance, which included distance covered during different movement categories (i.e., Stand Still, Walk, Jog, Run, Sprint). ...
There is a paucity of data examining the impact of high-intensity interval training in hypoxia (IHT) on intermittent running performance. This study assessed the effects of IHT on 17 amateur Australian Footballers, who completed eight interval treadmill running sessions [IHT (FIO2 = 15.1%) or PLACEBO] over four weeks, in addition to normoxic football (2/wk) and resistance (2/wk) training sessions. To match relative training intensity, absolute IHT intensity reduced by 6% of normoxic vVO2peak compared with PLACEBO. Before and after the intervention, performance was assessed by Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) and a self-paced team sport running protocol. Standardised effect size statistics were calculated using Cohen's D to compare between the interventions. Compared with PLACEBO, IHT subjects experienced: (a) smaller improvements in Yo-Yo IR2 performance [Cohen's D = -0.42 (-0.82 to -0.02; 90% confidence interval); (b) similar increases in high-intensity running distance during the team sport protocol [D = 0.17 (-0.50 to 0.84)]; and (c) greater improvements in total distance [D = 0.72 (0.33 to 1.10)] and distance covered during low-intensity activity [D = 0.59 (-0.07 to 1.11)] during the team sport protocol. The lower absolute training intensity of IHT may explain the smaller improvements in Yo-Yo IR2 performance in the hypoxic group. Conversely, the data from the self-paced protocol suggest that IHT may positively influence pacing strategies in team sport athletes. In conclusion, IHT alters pacing strategies in team sport athletes (i.e. increased distance covered during low intensity activity). However, IHT leads to smaller improvements in externally paced high-intensity intermittent running performance (i.e. Yo-Yo IR2), which may be related to a reduced absolute training intensity during IHT sessions. .
... Specifically, in the dominant force, a CV of 13.09% and 10.75% was found in the peak and average force, respectively (sessions one and two) and 6.71% and 6.61% (sessions three and four). Thus, this is in line with other research, such as that of Doma et al. [21] where they reached this conclusion on the reliability of the sprint with a CV of 4.3 to 20.7% (between sessions one and two) and 3.2-10.1% (between sessions three and four), conclusions similar to those of Tofari et al. [29] or those of García-Ramos et al. [28] with three devices for measuring force in the blocks, highlighting that for these authors, the intrasession CV was lower than the intersession as in our research. At the same time, this result is not new, given that authors such as Hopker et al. [30] also saw this need; therefore, familiarization with at least two sessions and two trials per session was essential to achieve adequate reliability [28]. ...
Aims: To determine the intrasession and intersession reliability of the isometric force at
three different starting block positions, to compare the intrasession and intersession reliability of the peak and average isometric force of three different starting block positions, and to compare the intrasession and intersession reliability of three different starting block positions. Methods: Eighteen male college students participated in this study. A repeated measures design was used to evaluate the intrasession and intersession reliability of isometric force in three different starting block positions.
Results: Very high and extremely high reliability of the average and peak isometric force of the three positions of the starting blocks were obtained, with ICC ranging from 0.63 to 0.91 and a CV close to 10%. Peak force was able to determine the outcomes of the bilateral position with higher reliability than the mean force, and the dominant was the most reliable position for assessing the starting blocks. Conclusion: The functional electromechanical dynamometer can be used with a high level of reliability to assess the force exerted in the starting blocks.
... The test-retest reliability statistical analyses included a consecutive pairwise intraclass correlation coefficient (ICC) (3, 1) and typical error represented as the coefficient of variation (CV%) ±90% confidence limits (CL) and difference in mean using a customized Excel spreadsheet (Hopkins, 2017). Tofari et al., 2015). If the CV% was smaller than the SWC, the 1RM and 5RM tests were considered sensitive enough to detect the SWC. ...
Background
Research into the kettlebell swing has increased in the last decade. There has been a paucity of literature assessing an individual’s ability to perform the kettlebell swing exercise. The purpose of this study was to determine the test-retest reliability of the one and five repetition maximum (1RM and 5RM) kettlebell swing.
Materials & Methods
Twenty four recreational resistance-trained participants performed an isometric mid-thigh pull (IMTP) and two familiarization sessions followed by three test sessions for each RM load approximately one week apart, using a custom-built plate-loaded kettlebell. On each test occasion, subjects completed a series of warm-up sets followed by 3–4 progressively heavier kettlebell swings to a standardized height until 1RM or 5RM was reached. Test-retest reliability was calculated using the intra-class correlation (ICC) and typical error was represented as the coefficient of variation (CV%) with 90% confidence limits (90% CL). The smallest worthwhile change (SWC%) representing the smallest change of practical importance, was calculated as 0.2 × between-subject standard deviation. The relationship of kettlebell swing performance and maximum strength was determined by Pearson correlation with ±90% CL between the absolute peak force recorded during IMTP and 1RM or 5RM.
Results
Results demonstrated a high test-retest reliability for both the 1RM (ICC = 0.97, 90% CL [0.95–0.99]; CV = 2.7%, 90% CL [2.2–3.7%]) and 5RM (ICC = 0.98, 90% CL [0.96–0.99]; CV = 2.4%, 90% CL [1.9–3.3%]), respectively. The CV% was lower than the SWC for both the 1RM (SWC = 2.8%, 90% CL [1.9–3.5]) and 5RM (SWC = 2.9%, 90% CL [1.9–3.6]) kettlebell swing. The correlation between IMTP absolute peak force and the 1RM (r = 0.69, 90% CL 0.43–0.83) was large and very large for the 5RM (r = 0.75, 90% CL [0.55–0.87]).
Conclusions
These results demonstrate the stability of 1RM and 5RM kettlebell swing performance after two familiarization sessions. Practitioners can be confident that changes in kettlebell swing 1RM and 5RM performance of >3.6 kg represent a practically important difference, which is the upper limit of the 90% CL.
... Numerous participants can simultaneously undertake a free-running simulation, thus, researchers with a time efficient agenda may benefit from the reduced time burden involved with completion. This model also enables players to attain maximum speeds, though players are able to adopt pacing approaches as these simulations are typically externally paced (e.g., running speeds are often guided by audible commands; Tofari et al. 2015). These simulations tend to closely resemble soccer match dynamics, though incorporating skill tasks within the design may prove complex for technically incapable cohorts, which can jeopardise the physical impetus of the simulation (Russell and Kingsley,2011). ...
Soccer is a fast-growing area of research, demonstrated by a 10-fold increase in the number of PubMed articles derived from the search term 'soccer' between 2001 and 2021. The scope of 1 contemporary soccer-related articles ranges from match-play observations to laboratory evaluations of performance. The activity profile of soccer match-play is variable and techniques to collect data within matches are limited. Soccer-specific simulations have been developed to simulate the evolving demands of match-play. The evolutionary designs of novel simulations provide a reproducible exercise stimulus for varying researcher and practitioner objectives. The applied researcher can utilise simulations to investigate the efficacy of nutritional interventions and environmental stress on performance, while assessing the physiological and biomechanical responses to representations of match-play. Practitioners can adopt simulations for rehabilitation to progressively facilitate return-to-play processes, while implementing extra top-up conditioning sessions for unused and partial-match players. However, there are complexities involved with the selection of varying simulations which are dependent on the research question or practical application. There also remains a paucity of published information to support researchers and practitioners in selecting from differing simulation models. To assist with researcher and practitioner interpretations, we present a commentary of the current simulations to inform decision-making processes for research and training purposes and enhance the application of future research. An objective scoring system was adopted for rating the research and practical applications of each simulation design. Overall scores of 22, 16 and 18 out of 36 were revealed for free-running (n=7), non-motorised-(n=4) and motorised-treadmill-based simulations (n=4), respectively.
... The main difference compared to motorized treadmills (MT) is that cNMT allows participants to self-select the speed and allows a more valid and ecological laboratory assessment of running performance [25,26]. While different studies have been analysing the cNMT on sprints [27], endurance running [26], cardiometabolic demands [28,29] and team-sport running [30]; other studies have focused on physiological and perceptual variables comparing cNMT with MT [21,25], and overground running [23]. ...
An increase in the popularity of running can be seen over the last decades, with a large number of injuries on it. Most of the running injuries are related to impact accelerations and are due to overuse. In order to reduce the risk of injury or to improve performance and health new treadmill designs have been created, as it can be the curved non-motorized treadmill. The aim of this study was to analyse impact accelerations, spatio-temporal parameters and perceptual differences while running on curved non-motorized treadmill (cNMT) compared to motorized treadmill (MT) at different speeds. Therefore, 27 recreational runners completed two tests consisting of 10 min warm-up and three bouts of 8 min running at 2.77 m/s, 3.33 m/s and self-selected speed on cNMT and MT, previously randomised. Although the surface did not influence spatio-temporal parameters, a reduction in impact accelerations, head acceleration rate (mean effect size [ES] = 0.86), tibia peak (mean ES = 0.45) and tibia magnitude (mean ES = 0.55), was observed while running on cNMT in comparison with running on MT. Moreover, higher heart rate (HR) (mean ES = 0.51) and rating of perceived effort (RPE) (mean ES = 0.34) were found while running on cNMT. These findings demonstrated that higher intensity training and lower impact accelerations are experimented on cNMT, what can be used by trainers and athletes while planning training sessions.
... For example, the current interchange rugby league simulation protocol comprises repeated cycles of activity (115 s) lasting 46 min. 5 The use of short repeated cycles is common in team sport simulation protocols, [6][7][8] with few exceptions, 9 which is likely an attempt to maintain the consistency of performance in such activities. 5 However, preserving high internal validity and associated reliability might compromise the external validity of such protocols. ...
Purpose:
To examine responses to a simulated rugby league protocol designed to include more stochastic commands, and therefore require greater vigilance, than traditional team-sport simulation protocols.
Methods:
Eleven male university rugby players completed 2 trials (randomized and control [CON]) of a rugby league movement simulation protocol, separated by 7 to 10 d. The CON trial consisted of 48 repeated ∼115-s cycles of activity. The stochastic simulation (STOCH) was matched for the number and types of activity performed every 5.45 min in CON but included no repeated cycles of activity. Movement using GPS, heart rate, rating of perceived exertion, and Stroop test performance was assessed throughout. Maximum voluntary contraction peak torque, voluntary activation (in percentage), and global task load were assessed after exercise.
Results:
The mean mental demand of STOCH was higher than CON (effect size [ES] = 0.56; ±0.69). Mean sprint speed was higher in STOCH (22.5 [1.4] vs 21.6 [1.6] km·h-1, ES = 0.50; ±0.55), which was accompanied by a higher rating of perceived exertion (14.3 [1.0] vs 13.0 [1.4], ES = 0.87; ±0.67) and a greater number of errors in the Stroop test (10.3 [2.5] vs 9.3 [1.4] errors; ES = 0.65; ±0.83). Maximum voluntary contraction peak torque (CON = -48.4 [31.6] N·m and STOCH = -39.6 [36.6] N·m) and voluntary activation (CON = -8.3% [4.8%] and STOCH = -6.0% [4.1%]) was similarly reduced in both trials.
Conclusions:
Providing more stochastic commands, which requires greater vigilance, might alter performance and associated physiological, perceptual, and cognitive responses to team-sport simulations.
... Anecdotally, some players indicated they had difficulty to "efficiently accelerate the belt" under fatigue. However, this model of NMT has previously been shown to be both valid and reliable across a range of representative team-sport speeds, including sprinting (Sirotic and Coutts, 2008;Aldous et al., 2014;Tofari et al., 2014). The lack of any difference in Playerload between testing sessions indicates that there was no learning effect or changes in gait as players completed more sessions on the curved NMT, although we recognize a lack of validity data specifically pertaining to Playerload on a curved NMT. ...
Repeated-sprint training in hypoxia (RSH) studies conducted "in-season" are scarce. This study investigated the effect of discontinuous, running-based RSH, on repeated-sprint treadmill performance in hypoxia in a team sport cohort, prior to international competition. Over a 6-week "in-season" period, 11 elite male players (Malaysia national team) completed eight multi-set RSH sessions on a non-motorized treadmill in a normobaric hypoxic chamber (FiO2 = 13.8%). Three testing sessions (Sessions 1, 5, and 8), involved three sets of 5 × 8-s sprints, with 52-s recovery between sprints and 4-5 min between sets. Training sessions (Sessions 2, 3, 4, 6, and 7) consisted of four to five sets of 4-5 × 8-s sprints. During testing sessions, maximum sprinting speed was recorded for each sprint with values averaged for each set. For each set, a peak speed and fatigue index were calculated. Data were compared using two-way repeated measures ANOVA (sessions × sets). Average speed per set increased between testing sessions (p = 0.001,
η
p
2
= 0.49), with higher values in Session 8 (25.1 ± 0.9 km.h-1, +4 ± 3%, p = 0.005), but not Session 5 (24.8 ± 1.0 km.h-1, +3 ± 3%, p = 0.405), vs. Session 1 (24.2 ± 1.5 km.h-1). Peak sprinting speed in each set also increased across testing sessions (p = 0.008,
η
p
2
= 0.382), with Session 8 (26.5 ± 1.1 km.h-1) higher than Session 5 (25.8 ± 1.0 km.h-1, +1 ± 4%, p = 0.06) and Session 1 (25.7 ± 1.5 km.h-1, +4 ± 4%, p = 0.034). Fatigue index differed between sessions (p = 0.04,
η
p
2
= 0.331, Session 1; -6.8 ± 4.8%, Session 5; -3.8 ± 2%, Session 8; -5.3 ± 2.6%). In international field hockey players, a 6-week in-season RSH program improved average and peak, repeated treadmill sprint speeds following eight, but not five sessions.
... The reliability of measures used in power sports applications provided by flat-surfaced and curved designs of NMTs has been well-established against overground sprinting (Highton et al., 2012), CE (Chia and Lim, 2008;Gonzalez et al., 2013), or on separate days (Tong et al., 2001;Hughes et al., 2006) even with minimal familiarization (Glaister et al., 2007). Consequently, NMTs are now used along with CE for RSA testing (Sutton et al., 2000;McLain et al., 2015;Tofari et al., 2015) and used to simulate specific demands of field-based sports (Carling et al., 2012;Nédélec et al., 2013;Aldous et al., 2014). ...
This study aimed to compare the time course of measures of performance, fatigue, and perceived exertion during repeated-sprint ability (RSA) testing performed on a non-motorized treadmill (NMT) and cycling ergometer (CE). Fourteen physically active participants performed two 10 ×6 s−1 RSA tests with a 1:4 work-to-rest ratio (24 s recovery) on NMT and CE. Measures of performance [peak and mean power output (PPO and MPO), cadence, and the time to reach PPO (TTP)] and of fatigue (fatigue index and decrement score) and ratings of perceived exertion (RPE) were collected during each session. The level of significance was set at p < 0.05. Participants completed the RSA test at a MPO of 1,041 ± 141 W on CE and 431 ± 48 W on NMT, achieving PPO of 2,310 ± 339 W on CE and 1,763 ± 289 W on NMT. Participants' weight was significantly correlated with PPO and MPO on CE (p < 0.001) and with MPO on NMT (p < 0.001). PPO on CE and NMT was significantly correlated only for absolute measures of power (p < 0.01). Cadence was higher and decreased throughout the RSA on NMT compared to CE, where it decreased only at the seventh bout. TTP was significantly shorter and more affected by fatigue on NMT than on CE. Fatigue indices were significantly greater on NMT compared to CE, with significant correlations between the decrement score and absolute and relative PPO on CE and NMT, between the fatigue index and absolute and relative PPO only on NMT, and no significant correlations with MPO. During RSA, RPE increased more on NMT compared to CE from bouts 3 to 7. During recovery, RPE was consistently higher on NMT at 1, 3, and 5 min post exercise compared to CE. These findings indicate that RSA performed on NMT induces greater fatigue and physiological load than CE, which originated in the lower resistive torque typically used on NMT compared to CE, resulting in a front loaded power output profile from the greater acceleration and cadence. From these results, we discuss that despite providing highly correlated measures of power output, NMT and CE should not be used interchangeably to assess RSA as they elicit markedly different responses. We also discuss these results from the fundamental differences in active muscle mass and power application patterns between running and cycling, which could form the basis of future studies.
... Additionally, multiple CMJ, SJ and IMTP tests were performed in each session to ensure compliance with procedures and repeatability of test outcomes Sheppard and Doyle 2008;Comfort et al. 2019). Two 15 min portions of a match simulation protocol on a flat NMT are appropriate for familiarization (Sirotic and Coutts 2008), however previous work using a curved NMT has shown one session is adequate (Tofari et al. 2015(Tofari et al. , 2018. ...
Introduction: Competitive soccer results in acute physiological and perceptual disturbances lasting up to 96-h, yet multiple games are often played with 72-h rest. Contextual factors influence match activities, impacting the assessment of post-match responses. We assessed the within- and post-match responses to two self-paced simulations (SIM1 and SIM2) in a 72-h period. Method: Eleven male team-sport athletes attended eight consecutive testing sessions after familiarisation. Assessments occurred at pre-, half-time, post- and 2 h post-SIM1, and daily up to four-days after SIM2. Statistics included effect size ± 90% CL comparisons to pre-SIM1 and regression analysis. Results: At half time there was reduced voluntary activation (SIM1: −1.52 ± 1.41 and SIM2: −0.50 ± 0.58) and potentiated twitch torque (SIM1: −0.50 ± 0.37 and SIM2: −0.31 ± 0.37), suggesting central and peripheral fatigue, respectively. The difference in activity profiles between simulations was unclear. Both simulations resulted in acute physiological and perceptual decrements, similar to published data from competitive matches. Higher strength was associated with reduced soreness and fatigue at all time points (range: r = 0.27 to 0.69) and lower peripheral fatigue. vV.O2peak was negatively associated with CK (range: r = −0.28 to −0.70). Conclusion: 72-h recovery is sufficient to maintain activity between simulations. Lower-body strength and aerobic capacity displayed protective effects against post-simulation decrements.
... This sequence was repeated four more times, with the sprint efforts of 80%, 90%, 100%, and 100%, respectively. Running at selfperceived maximal effort has been shown to be a reliable method of setting running speed on a non-motorised treadmill (Tofari, McLean, Kemp, & Cormack, 2015). ...
Accelerometers are often placed on the tibia to measure segmental accelerations, and external mechanical load during running. However, in applied sport settings it is sometimes preferable to place accelerometers on the dorsal foot to avoid tibial impact injuries. This study aimed to quantify the differences in accelerations measured at the dorsal foot compared with the distal tibia during running. Sixteen recreationally active participants performed a sprint protocol on a non-motorised treadmill. Accelerometers were positioned bilaterally on the medial tibia (TIBLeft and TIBRight), and bilateral dorsal foot surfaces (DORLeft and DORRight). Continuous acceleration signal waveform analysis was performed using one-dimensional statistical parametric mapping (1DSPM). Resultant accelerations were greater for DORLeft than TIBLeft for 60% of the gait cycle (p < 0.001) and greater for DORRight than TIBRight for 50% of the gait cycle (p < 0.003). The larger accelerations at the dorsal foot than the tibia can be explained by movement at the ankle joint, and the placement location relative to the hip. The dorsal foot location can be used to effectively measure accelerations and external mechanical load when it is not feasible to place the accelerometer on the tibia, however results between the two locations should not be compared.
... The Woodway Curve non-motorised treadmill contains four load cells (on the left and right side, at the front and rear of the treadmill belt) that measure vertical ground reaction force at 200 Hz. 21 According to our contact time data (e.g. see Table 1), this would provide >20 sample points in the propulsive phase (i.e. for ~30 sample points per ground contact. ...
Objectives:
To quantify changes in running kinetics and kinematics during a repeated-sprint test in football players, and explore the sensitivity and specificity with which these variables can identify previous hamstring injury.
Design:
20 Western Australia State League footballers with previous unilateral hamstring injury and 20 players without completed a 10×6-s repeated-sprint test on a non-motorised treadmill dynamometer.
Methods:
Changes in horizontal force, vertical force, contact time and flight time were compared between previously injured and uninjured legs of participants.
Results:
Mean horizontal force production of the previously injured leg in the injured group was 13% lower (p=0.001), and this magnitude of change was used to identify the injured legs within the cohort with 77% specificity and 85% sensitivity. Furthermore, the area under the Receiver Operating Characteristics curve (0.846) demonstrated that the between-leg difference in mean horizontal force was a good instrument for identifying previous hamstring injury.
Conclusions:
There is a greater fatigued-induced change in mean horizontal force during a repeated-sprint test in legs with previous hamstring injury than the non-injured legs of the injured players or the legs of uninjured players. Such asymmetry may contribute to impaired performance in football players returning from hamstring injury and also to the high rate of hamstring re-injury. Rehabilitation and return-to-play strategies should emphasise a reduction in asymmetry, particularly during repeated high-intensity efforts. Furthermore, binary regression and Receiver Operating Characteristic analyses suggest that changes in mean horizontal force could be used to assess risk of hamstring injury, re-injury and/or return to play.
... 2,4,5,7 Even in cases in which different speeds are compared, only a single curvature radius is considered. 3,8 Thus, very few studies have considered the exercise characteristics and effects of NMCTs for various curvature radii and speeds. ...
It is generally believed that running on a curved surface is more unstable than running on a flat surface. In this study, the dynamic stability of locomotion on a nonmotorized curved treadmill (NMCT) with three curvature radii was compared with that on a motorized flat treadmill. Sixteen healthy adult men maintained four different self-paced speeds: slow walking, fast walking, jogging, and running. Significant differences were statistically verified using two-way repeated-measures analysis of variance (ANOVA) according to the curvature radii and speeds, and the interaction effects were confirmed. Furthermore, to understand the significant differences between the speed and curvature radius, post hoc analyses were performed using one-way ANOVA. Except for the step width, the other parameters showed differences and correlation effects between the curvature radius and speed. As the curvature radius decreased, the stability decreased at slow speeds (slow walking) but increased at fast speeds (running). However, as the curvature radius increased, the stability increased at slow speeds (slow walking) but decreased at high speeds (running). The study results will help in suggesting the appropriate curvature radius for different user types such as athletes, the elderly, and people who require rehabilitation and will serve as preliminary data for designing the curvature radii of NMCTs.
... The duration and frequency of these efforts were based on previous research that has characterised player movements in a typical game of AF 23,24 ; based on those player movement data a running protocol was devised to simulate a game of AF similar to previous researchers. 25,26 Defined movement patterns (and relative speeds) include: stand (0% max), walk (20% max), jog (35% max), fast run (65% max), maximal sprint (max speed). At each change in effort the participant received audio and visual cues to increase or decrease their running speed. ...
Objectives
To investigate how knee kinematics, kinetics and loading changes during sidestepping tasks following a prolonged running protocol performed in a laboratory setting.
Design
All participants performed sidestepping, and crossover cutting tasks in a randomised order before and after a 60 minute running protocol on a non-motorised treadmill that simulated an AF game.
Method
Eight healthy male participants who partook in semi-professional and amateur Australian Football undertook a series of straight line runs, sidestepping (SS), and crossover cutting (XO) tasks before and after a simulated game of Australian football. Kinematic data were analysed at initial foot contact of the SS and XO manoeuvres and kinetic data were analysed during the weight acceptance phase of the stance.
Results
The knee was significantly more flexed at foot contact following fatigue compared to pre-fatigue states. Fatigue was also a factor contributing to significant increases in internal knee extension moments. Significant differences were also observed between SS and XO trials with flexion/extension moments, with notable differences in varus/valgus and internal/external rotation moments.
Conclusion
Acute angles of knee flexion at foot strike in a fatigued state may place the joint at an increased risk of injury. Increases in knee extension moments in the fatigued state suggests the knee joint must withstand significantly high stresses once fatigued.
... One familiarisation session on the NMT may be insufficient, two familiarisations could be optimal [31]. However, previous studies did not use only constant velocities which might negate the need for extra familiarisation, particularly as one familiarisation session has shown good reliability [32] and that participants all sufficiently met target velocities during familiarisation. High inter and intra participant variability for EMG was present, likely due to individual walking, jogging and running techniques which was expected, yet unavoidable. ...
Purpose:
To examine tibial acceleration and muscle activation during overground (OG), motorised treadmill (MT) and non-motorised treadmill conditions (NMT) when walking, jogging and running at matched velocities.
Methods:
An accelerometer recorded acceleration at the mid-tibia and surface EMG electrodes recorded rectus femoris (RF), semitendinosus (ST), tibialis anterior (TA) and soleus (SL) muscle activation during OG, MT and NMT locomotion whilst walking, jogging and running.
Results:
The NMT produced large reductions in tibial acceleration when compared with OG and MT conditions across walking, jogging and running conditions. RF EMG was small-moderately higher in the NMT condition when compared with the OG and MT conditions across walking, jogging and running conditions. ST EMG showed large and very large increases in the NMT when compared to OG and MT conditions during walking whilst SL EMG found large increases on the NMT when compared to OG and MT conditions during running. The NMT condition generated very large increases in step frequency when compared to OG and MT conditions during walking, with large and very large decreases during jogging and very large decreases during running.
Conclusions:
The NMT generates large reductions in tibial acceleration, moderate to very large increases in muscular activation and large to very large decreases in cycle time when compared to OG and MT locomotion. Whilst this may decrease the osteogenic potential of NMT locomotion, there may be uses for NMTs during rehabilitation for lower limb injuries.
Soccer matches have a typical duration of 90 min. However, when matches are drawn in some knockout cup scenarios and an outright winner is required, an additional 30 min period, termed extra-time (ET), is played. The performance and physiological responses to 90 min of soccer-specific exercise have been extensively investigated, however; there is a paucity of research investigating the demands of 120 min of soccer-specific exercise (i.e., matches requiring ET). Accordingly, the aims of this thesis were 1) to elucidate professional practitioner perceptions of ET, 2) to investigate the performance and physiological responses during prolonged actual and simulated match-play, and 3) to examine the influence of a nutritional intervention on performance during ET.
To actuate aim one, a qualitative approach (i.e., an online survey) was used to assess practitioner perceptions of ET and their current applied practices. To accomplish aim two, quantitative research projects utilising performance analysis techniques and an analogue of match-play (simulated soccer match) were used. To actuate aim three, the same analogue of match-play was used to investigate the effect of carbohydrate-electrolyte gels ingested prior to ET on performance and physiology.
Practitioners generally account for ET when preparing and recovering players and the majority (91%) of practitioners want research to be conducted on ET. Using notational analysis, reductions in technical performance (i.e., passing and dribbling) were observed during ET. Furthermore, when using a simulated match protocol, perturbations in both performance and physiology compared to the previous 90 min of exercise occur. Specifically, reductions in both physical (i.e., sprint speeds) and technical (i.e., shooting speed) parameters, taxing of endogenous fuel sources, dehydration, and shifts in substrate utilisation (i.e., a move towards fat oxidation as a fuel source) were observed. The ingestion of carbohydrate-electrolyte gels prior to ET improved dribbling performance, however; this intervention was unable to attenuate decrements in physical performance and hydration status.
In conclusion, ET influences both soccer-specific performance and physiological responses. In agreement with practitioners working in professional soccer, more research is required to investigate the efficacy of interventions (particularly hydro-nutritional interventions) that improve performance and ameliorate perturbations in physiology and metabolism.
There are a wide range of options for individuals to choose from in order to engage in aerobic exercise; from outdoor running to computer controlled and self-propelled treadmills. Recently, self-propelled treadmills have increased in popularity and provide an alternative to a motorized treadmill. Twenty subjects (10 men, 10 women) ranging in age from 19-23 with a mean of 20.4 ± 0.8 SD were participants in this study. The subjects visited the laboratory on three occasions. The purpose of the first visit was to familiarize the subject with the self-propelled treadmill (Woodway Curve 3.0). The second visit, subjects were instructed to run on the self-propelled treadmill for 3km at a self-determined pace. Speed data were collected directly from the self-propelled treadmill. The third visit used speed data collected during the self-propelled treadmill run to create an identically paced 3km run for the subjects to perform on a motorized treadmill (COSMED T150). During both the second and third visit, oxygen consumption (VO2) and respiratory exchange ratio (R) data were collected with COSMED’s Quark cardiopulmonary exercise testing (CPET) metabolic mixing chamber system. The VO2 mean value for the self-propelled treadmill (44.90 ± 1.65 SE ml/kg/min) was significantly greater than the motorized treadmill (34.38 ± 1.39 SE ml/kg/min). The mean R value for the self-propelled treadmill (0.91 ± 0.01 SE) was significantly greater than the motorized treadmill (0.86 ± 0.01 SE). Our study demonstrated that a 3km run on a self-propelled treadmill does elicit a greater physiological response than a 3km run at on a standard motorized treadmill. Self-propelled treadmills provide a mode of exercise that offers increased training loads and should be considered as an alternative to motorized treadmills.
Understanding dynamic stability during locomotion is very important for preventing falling and injury. Although many previous studies have investigated dynamic stability characteristics under self-paced speed (SP) and fixed-speed (FS) conditions, very few have directly compared the two conditions. In this study, the margin of stability (MOS) was evaluated under the SP and FS conditions using a nonmotorized curved treadmill (NMCT). Interaction effects were found between the curvature radius and speed, the differences between each curvature radius and speed were confirmed, and significant differences were found between the SP and FS conditions. According to experimental results, under both the SP and FS conditions, the dynamic stability increased with the curvature radius during slow and fast walking. However, under the SP condition, as the curvature radius increased, the MOS in the anteroposterior direction decreased during running; however, under the FS condition, no distinctive trend was observed. At most curvature radii and speeds, significant differences were found between the SP and FS conditions. The study results indicated that while exercising on the NMCT, the SP and FS conditions at different curvature radii and speeds could influence the dynamic stability. The results could be utilized for verifying exercise capacity enhancement and rehabilitation exercise effects. © 2017, Korean Society for Precision Engineering and Springer-Verlag GmbH Germany.
Assessing responses to soccer match-play is limited by match variability or unrealistic simulations. To address this, the biological, perceptual, and performance response were assessed using a self-paced, simulated soccer match protocol using a non-motorized treadmill. Twelve male team-sport athletes performed the 90-min simulation. Match activity; quadriceps twitch interpolation [voluntary activation (%VA) and potentiated twitch (POT)]; biochemical markers; strength and power performance; rating of perceived exertion (RPE) and self-report wellness were collected pre-, half-time, post-, and 2, 24, 48, 72 and 96-h post-match. Change compared to pre-match was calculated using effect size (ES) ±90% confidence limit, and relationships were assessed using regression analysis. Subjects covered 12445.8±768.7 m at 87.1±3.2% maximal HR (mean±SD). Reductions in %VA and POT was present at half-time (-0.38±0.46 and -0.79±0.30, respectively), and persisted post-match. Squat jump height decreased at half-time (-0.42±0.31) and was decreased until Post96. Perceptual fatigue, soreness (-0.92±0.88 and -1.49±0.76, respectively) and creatine kinase (CK, 1.11±0.43) peaked at Post24. Pre-test strength (N.kg) correlated with changes in CK (r=-0.58 to -0.81), peak oxygen consumption (V˙ O2peak) correlated with reduced perceived wellness at Post24 (r=0.44 to 0.58) and RPE post (r=-0.71±0.28). High-speed running correlated with soreness (r=0.42) and very high speed running with reduced POT (r=0.61). Previously unreported half-time reductions in %VA and POT plateaued by post-match, suggesting a role in regulating second-half performance. Perceptual and neuromuscular responses appear related to running intensity. Greater lower-body strength and V˙ O2peak were associated with less CK (i.e., muscle damage) and perceptual responses post-match, respectively, suggesting a training focus should be placed on these capacities.
This study aimed to determine if ice slurry ingestion improved self-paced intermittent exercise in the heat. After a familiarisation session, 12 moderately trained males (30.4 ± 3.4 year, 1.8 ± 0.1 cm, 73.5 ± 14.3 kg, V˙O2max 58.5 ± 8.1 mL/kg/min) completed two separate 31 min self-paced intermittent protocols on a non-motorised treadmill in 30.9 ± 0.9 °C, 41.1 ± 4.0% RH. Thirty minutes prior to exercise, participants consumed either 7.5 g/kg ice slurry (0.1 ± 0.1 °C) (ICE) or 7.5 g/kg water (23.4 ± 0.9 °C) (CONTROL). Despite reductions in Tc (ΔTc : -0.51 ± 0.3 °C, P < 0.05) and thermal sensation prior to exercise, ICE did not enhance self-paced intermittent exercise compared to CONTROL. The average speed during the walk (CONTROL: 5.90 ± 1.0 km, ICE: 5.90 ± 1.0 km), jog (CONTROL: 8.89 ± 1.7 km, ICE: 9.11 ± 1.5 km), run (CONTROL: 12.15 ± 1.7 km, ICE: 12.54 ± 1.5 km) and sprint (CONTROL: 17.32 ± 1.3 km, ICE: 17.18 ± 1.4 km) was similar between conditions (P > 0.05). Mean Tsk , Tb , blood lactate, heart rate and RPE were similar between conditions (P > 0.05). The findings suggest that lowering Tc prior to self-paced intermittent exercise does not translate into an improved performance.
The aim of this study was to examine the association between match metabolic power (MP) categories and aerobic-fitness in elite-level male soccer players. Seventeen male professional soccer players were tested for VO2max, maximal aerobic speed (MAS), VO2 at ventilatory threshold (VO2VT and % VO2VT) and speed at a selected blood-lactate concentration (4 mmol· l, VL4). Aerobic-fitness tests were performed at end of pre-season and after 12 and 24 weeks during the championship. Aerobic fitness and MP variables were considered as mean of all seasonal testing and of 16 Championship home matches for all the calculations, respectively. Results showed that VO2max (from 0.55 to 0.68), MAS (from 0.52 to 0.72), VO2VT (from 0.72 to 0.83), %VO2VT (from 0.62 to 0.65) and VL4 (from 0.56 to 0.73) were significantly (p< 0.05 to 0.001) large to very large associated with MP variables. These results provide evidence to the ecological validity of aerobic-fitness in male professional-soccer. Strength and conditioning professionals should consider aerobic-fitness in their training program when dealing with professional male soccer players. The MP method resulted an interesting approach for tracking external-load in male professional soccer-players.
The relationships between 30m sprint time and performance on a non-motorized treadmill test, as well as a vertical jump test were determined in the present investigation. Seventy-eight physically active men and women (22.9±2.7 y; 73.0±14.7 kg; 170.7±10.4 cm) performed a 30-s maximal sprint on the Curve™ non-motorized treadmill (TM) following one familiarization trial. Pearson product-moment correlation coefficients produced significant (p<0.05) moderate to very strong relationships between 30m sprint time and body mass (r= -0.37), %Fat (r=0.79), peak power (r= -0.59), relative peak power (r= -0.42), time to peak velocity (r= -0.23), as well as TM sprint times at 10m (r=0.48), 20m (r=0.59), 30m (r=0.67), 40m (r=0.71), and 50m (r=0.75). Strong relationships between 30m sprint time and peak- (r= -0.479) and mean vertical jump power (r= -0.559) were also observed. Subsequently, stepwise regression was used to produce two 30m sprint time prediction models from TM performance (TM1: body mass+TM-data; and TM2: body composition+TM-data) in a validation group (n=39) and then cross-validated against another group (n=39). As no significant differences were observed between these groups, data was combined (n=72) and used to create the final prediction models (TM1: r=0.75, SEE=0.27s; TM2: r=0.84, SEE=0.22s). These final movement-specific models appear to be more accurate in predicting 30m sprint time than derived peak- (r=0.23, SEE=0.48s) and mean vertical jump power (r=0.31, SEE=0.45s) equations. Consequently, sprinting performance on the TM can significantly predict short-distance sprint time. It therefore, may be used to obtain movement-specific measures of sprinting force, velocity, and power in a controlled environment from a single 30-s maximal sprinting test.
: The current study investigated the reliability and validity of a novel non-motorised treadmill (NMT) based soccer simulation utilising a novel activity category called a 'variable run' to quantify fatigue during high-speed running. Twelve male University soccer players completed three familiarisation sessions and one peak speed assessment before completing the Intermittent Soccer Performance Test (iSPT) twice. The two iSPT's were separated by 6 - 10 days. The total distance, sprint distance and high-speed running distance were 8968 ± 430 m, 980 ± 75 m and 2122 ± 140 m, respectively. No significant difference (p>0.05) was found between repeated trials of the iSPT for all physiological and performance variables. Reliability measures between iSPT1 and iSPT2 showed good agreement (CV: <4.6%; ICC: >0.80). Furthermore, the variable run phase showed high-speed running distance significantly decreased (p<0.05) in the last 15 min (89 ± 6 m) compared to the first 15 min (85 ± 7 m), quantifying decrements in high-speed exercise compared to previous literature. The current study validates the iSPT as a NMT based soccer simulation compared to previous match-play data, and is a reliable tool for assessing and monitoring physiological and performance variables in soccer players. The iSPT could be utilised in a number of ways including player rehabilitation, understanding the efficacy of nutritional interventions, and also the quantification of environmentally mediated decrements upon soccer-specific performance.
Abstract The aim of this study was to include self-paced exercise within a modified Loughborough Intermittent Shuttle Test (LIST-P) in order to quantify key performance variables not possible with prescribed workloads. Sixteen male games players performed two trials of the LIST-P, at least 7 days apart. The LIST-P incorporates 4 × 15-min blocks of "prescribed-pace" activity (participants exercise in time to audible signals) followed by 2 × 15-min blocks of "self-paced" running (no audible signals). Distances covered and mean speeds were monitored during self-paced exercise. Total distance covered (12.54 ± 0.45 km vs. 12.64 ± 0.32 km; P = 0.10) and mean speed (8.37 ± 0.31 km ∙ h(-1) vs. 8.44 ± 0.22 km ∙ h(-1); P = 0.10) was similar between trials. Other indices also showed the test to be reliable (Pearson's correlation = 0.89 and 0.90 (P < 0.01), total distance and mean speed, respectively; intraclass correlation coefficient = 0.88 and 0.88 (P < 0.01); standard error of measurement = ±0.13 km and ±0.09 km ∙ h(-1); coefficient of variation (CV) = 1.7% and 1.7%; ratio limits of agreement = 1.00 */÷1.03 and 1.01 */÷1.04). Sprint time was also similar between trials (2.60 ± 0.19 s vs. 2.64 ± 0.23 s; P = 0.29). Incorporating self-paced exercise within an established intermittent shuttle running test appears to be a sensitive means of quantifying key performance variables for multiple-sprint sports research.
The purpose of this study was to analyse the impact of an intermittent test reproducing the soccer running activity profile on physical performance, subjective ratings and biochemical parameters throughout 72 h recovery. 8 professional soccer players performed the intermittent test on a non-motorised treadmill and data was collected before, immediately after, 24, 48 and 72 h after the test. Squat jump (SJ), countermovement jump (CMJ), peak isometric force (IFpeak), 6-s sprint, repeated sprints test (RS), perceptual ratings (fatigue, muscle soreness, stress), creatine kinase ([CK]) and uric acid ([UA]) were analyzed. After the test, a mean reduction in countermovement jump performance of - 8.2% (CI: - 12.9 to - 3.4, p<0.01) was observed, while perceived fatigue (+2.1±1.7 a.u.; p<0.05), perceived muscle soreness (+1.8±1.5 a.u.; p<0.05), perceived stress (+1.6±1.5 a.u.; p<0.05), creatine kinase (+171±77 IU.l - 1; p<0.01) and uric acid (+168±89 Umol.l - 1; p<0.01) concentrations were significantly increased relative to baseline. No significant effect was found for SJ, IFpeak, 6-s sprint, RS immediately after and throughout the 72 h following the test. In conclusion, soccer running performance does not appear to be the main cause of post soccer match-induced fatigue. Physical data provided by video match analysis systems is insufficient to accurately estimate the level of match fatigue.
Previous investigators have reported significant relationships between tests of physical qualities and physical match performance in high-intensity intermittent team sport (e.g. soccer) players. While rugby league requires competitors to perform high-intensity running, unlike most other high-intensity intermittent team sports, the physical demands are significantly increased through the large amounts of tackling, wrestling, and grappling that players are required to perform during match-play. This study investigated the relationship between tests of physical qualities and match performance in professional rugby league players, and determined whether running capacities were associated with the collision and repeated high intensity effort demands of match-play. Thirty-eight elite rugby league players (mean ± SD age, 23.1 ± 2.7 yr) performed tests of repeated sprint ability (6 x 20 m sprints on a 20 s cycle), prolonged high-intensity intermittent running ability (8 x 12 s shuttle sprints on a 48 s cycle), and estimated maximal aerobic power (multi-stage fitness test). Global positioning system data were collected during 16 professional rugby league matches. Players with better prolonged high-intensity intermittent running ability covered greater total distance and greater distance in high-speed running during match-play. However, inconsistent relationships were found between tests of running abilities and other match performance variables, with prolonged high-intensity running ability (negative), maximal aerobic power (positive), and repeated-sprint ability (no relationship) differentially associated with the total number of collisions and repeated high-intensity effort bouts performed in competition. These findings demonstrate the importance of prolonged high-intensity running ability to the match running performance of elite rugby league players, but also highlight the need for game-specific conditioning to prepare players for the high-intensity collision, and repeated-effort demands of the game.
This study examined the interday and intraday reliabilities and validities of various sprint performance variables on a nonmotorized treadmill (NMT) over distances of 10, 20, and 30 m. After habituation, 12 male team-sport players performed 3 sprints on the NMT on 2 separate days and an assessment of overground running performance, separated by 24 hours. Measurements included sprint times, mean and peak sprint speeds, and step length and frequency. Data analysis revealed no significant mean differences (p > 0.05) between NMT variables recorded on the same day or between days. Ratio limits of agreement indicated that the best levels of agreement were in 20-m (1.02 ×/÷ 1.09) and 30-m (1.02 ×/÷ 1.07) sprint times, peak (1.00 ×/÷ 1.06) and mean (0.99 ×/÷ 1.07) running speed, and step length (0.99 ×/÷ 1.09) and frequency (1.01 ×/÷ 1.06). The poorest agreement was observed for time to peak running speed (1.10 ×/÷ 1.47). These reliability statements were reinforced by coefficients of variation being <5% for all the variables except time to peak running speed (11%). Significant differences (p < 0.05) were observed between NMT and overground sprint times across all distances, with times being lower (faster) by approximately 25-30% overground. The correlations between NMT and overground variables were generally modest (0.44-0.67), and optimal for time to cover 30 m on day 2. Our data support NMT ergometry as a reliable tool for most of the sprint performance variables measured and reveal that the fastest 30-m overground sprinters were likely to be identifiable via NMT ergometry.
The aim of this study was to verify if yo-yo intermittent recovery test (level 2) (yo-yo IR2) score is linked to Australian football (AF) performance through match exercise intensity. Six week prospective study design. Twenty-one data sets were recorded from nine individual players that completed the yo-yo IR2, and played an Australian Football League match in the first five rounds of the 2010 season wearing a global positioning system (GPS) unit. Simple mediation modelling was used to analyse the inter-relationship between yo-yo IR2 score, match exercise intensity and AF performance. Playing position and experience were also incorporated into the model to identify conditional affects. A significant direct relationship was observed between yo-yo IR2 and number of ball disposals (p<0.1) and a significant indirect relationship was observed between yo-yo IR2 and number of ball disposals through distance travelled at high intensity (HIR m min(-1)) (p<0.1). Moderation analysis showed that playing position affected the relationship between of yo-yo IR2 and HIR m min(-1) (p<0.1) and HIR m min(-1) and total ball disposals (p<0.1). Playing experience also significantly affected the relationship between HIR m min(-1) and total ball disposals. This study is the first to identify the effects of yo-yo IR2 on total ball disposals through HIR m min(-1) performed during AF matches, and that playing position and playing experience affect these interactions.
There is little information describing the match running demands of elite-level Australian Rules Football (AF). The aims of this study were to examine: (1) match running demands; and (2) the influence of periods of increased physical activity on subsequent running performance in the Australian Football League. Time-motion analyses were performed 1-9 times per player from 16 professional AF players from the same club during games in 2005-2007, using portable global positioning systems during 65 matches. Game movements (standing, walking, jogging, running, higher-speed running, and sprinting) and distances (total distance covered [TD]; low-intensity activity [LIA, distance <14.4kmh(-1)]; and, high-intensity running distance [HIR, distance>14.4kmh(-1)]) were collected. The influence of the first half physical activities on second half activities, and each quarter on the subsequent quarter were analysed. The mean (+/-SD) TD and HIR distance covered during the games were 12,939+/-1145m and 3880+/-663m respectively. There were reductions in TD in the second (-7.3%), third (-5.5%) and fourth (-10.7%) quarters compared to the first quarter (p<0.01). The HIR was reduced after the first quarter (p<0.001). Players that covered larger TD or HIR during the first half or quarter decreased distance in the next half and quarter, respectively (p<0.001). These results show that a reduction in exercise intensity is inevitable during an AF match and that higher intensity activities reduce towards the end of games. High average speed during each half or quarter also affects subsequent running performance in elite-level AF.
The aim of the present study was to analyze the impact of Loughborough Intermittent Shuttle Test (LIST) versus soccer match on heart rate (HR), muscle damage, redox status, blood leukocytes and neuromuscular function throughout 72 h recovery. Sixteen male soccer players (21.3 +/- 1.1 years; 175.0 +/- 6.0 cm; 70.7 +/- 6.3 kg) completed LIST and performed a soccer match separated by 2 weeks and data were collected before, 30 min, 24, 48 and 72 h after LIST and match. HR, plasma creatine kinase (CK) activity, myoglobin (Mb), uric acid (UA), protein sulfhydryls (-SH), malondialdehyde (MDA) contents, total antioxidant status (TAS), blood leukocyte counts, delayed onset muscle soreness, 20 m sprint and jump performances, and maximal isokinetic knee extension and flexion were analyzed. HR after LIST was significantly lower than after the match. Post-match TAS was lower and UA was higher than after LIST. Thirty minutes and 24 h after soccer MDA was higher and -SH was lower than after LIST (P < 0.05). LIST and soccer match induced elevation in total leukocytes and a reduction in lymphocytes at 30 min. This reduction in blood lymphocytes 30 min after match was lower than after LIST. In conclusion, the impact of both exercises did not differ regarding the observed muscle damage markers and some neuromuscular parameters, although soccer requires higher cardiac demand and induced higher changes on redox status, adenine nucleotide metabolism and on lymphocyte counts than LIST, which should be taken into account when using LIST to simulate a match to study these type of physiological and biochemical-related endpoints.
The aims of this study were to describe and determine the test-retest reliability of an exercise protocol, the Loughborough Intermittent Shuttle Test (the LIST), which was designed to simulate the activity pattern characteristic of the game of soccer. The protocol consisted of two parts: Part A comprised a fixed period of variable-intensity shuttle running over 20 m; Part B consisted of continuous running, alternating every 20 m between 55% and 95% VO2max, until volitional fatigue. Seven trained games players (age 21.5+/-0.9 years, height 182+/-2 cm, body mass 80.1+/-3.6 kg, VO2max 59.0+/-1.9 ml x kg(-1) x min(-1); mean +/- s(x)) performed the test on two occasions (Trial 1 and Trial 2), at least 7 days apart, to determine the test-retest reliability of the sprint times and running capacity. The physiological and metabolic responses on both occasions were also monitored. The participants ingested water ad libitum during the first trial, and were then prescribed the same amount of water during the second trial. The 15 m sprint times during Trials 1 and 2 averaged 2.42+/-0.04 s and 2.43+/-0.04 s, respectively. Run time during Part B was 6.3+/-2.0 min for Trial 1 and 6.1+/-1.3 min for Trial 2. The 95% limits of agreement for sprint times and run times during Part B were -0.14 to 0.12 s and -3.19 to 2.16 min respectively. There were no differences between trials for heart rate, rating of perceived exertion, body mass change during exercise, or blood lactate and glucose concentrations during the test. Thus, we conclude that the sprint times and the Part B run times were reproducible within the limits previously stated. In addition, the activity pattern and the physiological and metabolic responses closely simulated the match demands of soccer.
Reliability, the consistency of a test or measurement, is frequently quantified in the movement sciences literature. A common metric is the intraclass correlation coefficient (ICC). In addition, the SEM, which can be calculated from the ICC, is also frequently reported in reliability studies. However, there are several versions of the ICC, and confusion exists in the movement sciences regarding which ICC to use. Further, the utility of the SEM is not fully appreciated. In this review, the basics of classic reliability theory are addressed in the context of choosing and interpreting an ICC. The primary distinction between ICC equations is argued to be one concerning the inclusion (equations 2,1 and 2,k) or exclusion (equations 3,1 and 3,k) of systematic error in the denominator of the ICC equation. Inferential tests of mean differences, which are performed in the process of deriving the necessary variance components for the calculation of ICC values, are useful to determine if systematic error is present. If so, the measurement schedule should be modified (removing trials where learning and/or fatigue effects are present) to remove systematic error, and ICC equations that only consider random error may be safely used. The use of ICC values is discussed in the context of estimating the effects of measurement error on sample size, statistical power, and correlation attenuation. Finally, calculation and application of the SEM are discussed. It is shown how the SEM and its variants can be used to construct confidence intervals for individual scores and to determine the minimal difference needed to be exhibited for one to be confident that a true change in performance of an individual has occurred.
The aim of this study was to quantify response to a soccer-specific intermittent (INT) treadmill protocol based on notational analysis of match-play. Ten male semiprofessional football players (age 24.7 +/- 4.4 yr, body mass 77.1 +/- 8.3 kg, VO2max 63.0 +/- 4.8 ml x kg x min(-1)) completed the 90 minute INT protocol and a steady-state (SS) protocol eliciting the same distance covered. Physiological (heart rate [HR], ratings of perceived exertion [RPE], blood lactate concentration, salivary cortisol concentration) and mechanical (electromyography [EMG] of biceps femoris and rectus femoris) responses were obtained at 15 minute intervals throughout each protocol. The physiological and mechanical responses were typically greater during the INT protocol than during the SS protocol, tending to increase as a function of exercise duration. The INT activity profile induces cumulative mechanical load on the musculoskeletal system. The increased incidence of injury toward the latter stages of match-play is attributed to compromised movement mechanics, rather than physiological strain.
The two Yo-Yo intermittent recovery (IR) tests evaluate an individual's ability to repeatedly perform intense exercise. The Yo-Yo IR level 1 (Yo-Yo IR1) test focuses on the capacity to carry out intermittent exercise leading to a maximal activation of the aerobic system, whereas Yo-Yo IR level 2 (Yo-Yo IR2) determines an individual's ability to recover from repeated exercise with a high contribution from the anaerobic system. Evaluations of elite athletes in various sports involving intermittent exercise showed that the higher the level of competition the better an athlete performs in the Yo-Yo IR tests. Performance in the Yo-Yo IR tests for young athletes increases with rising age. The Yo-Yo IR tests have shown to be a more sensitive measure of changes in performance than maximum oxygen uptake. The Yo-Yo IR tests provide a simple and valid way to obtain important information of an individual's capacity to perform repeated intense exercise and to examine changes in performance.
The two Yo-Yo intermittent recovery (IR) tests evaluate an individual’s ability to repeatedly perform intense exercise. The Yo-Yo IR level 1 (Yo-Yo IR1) test focuses on the capacity to carry out intermittent exercise leading to a maximal activation of the aerobic system, whereas Yo-Yo IR level 2 (Yo-Yo IR2) determines an individual’s ability to recover from repeated exercise with a high contribution from the anaerobic system. Evaluations of elite athletes in various sports involving intermittent exercise showed that the higher the level of competition the better an athlete performs in the Yo-Yo IR tests. Performance in the Yo- Yo IR tests for young athletes increases with rising age. The Yo-Yo IR tests have shown to be a more sensitive measure of changes in performance than maximum oxygen uptake. The Yo-Yo IR tests provide a simple and valid way to obtain important information of an individual’s capacity to perform repeated intense exercise and to examine changes in performance.
This study examined the relationship between the frequency of playing actions performed during a soccer match and the recovery kinetics after the match. Time motion analyses were performed on 10 professional soccer players during four competitive matches (14 observations) to determine the number of playing actions completed by players. Subjective ratings, creatine kinase and physical tests (countermovement jump, isometric maximum voluntary contraction of the hamstrings, 6-s sprint on a non-motorised treadmill) were performed before, 24 h, 48 h and 72 h after the match. During the 72-h recovery period, countermovement jump, isometric strength of the hamstring muscles and peak sprint speed significantly (p < 0.05) decreased, while muscle soreness increased (p < 0.05). Significant correlations were observed between the increase in muscle soreness and number of short sprints (< 5 m) performed at 48 h (r = 0.74, CI: 0.35 to 0.91, p < 0.01) and 72 h (r = 0.57, CI: 0.05 to 0.84, p < 0.05) following match-play. A significant relationship (r = -0.55, CI: -0.84 to -0.03, p < 0.05) was also observed between countermovement jump performance decrement at 24 h and the number of hard changes in direction performed. Soccer match play resulted in significant neuromuscular fatigue for up to 72 hours post-match and was dependent on the number of sprints and hard changes in direction performed during the match. Time motion analysis data currently used during a soccer match should quantify hard changes in direction and acceleration / deceleration phases to enable better estimations of post-match fatigue.
A curved treadmill offers a practical method of assessing anaerobic power by enabling unrestricted running motion and greater sport specificity. The purpose of this research was to determine reliability of a curved treadmill (cTM) sprint test and to compare performance measures to the traditional Wingate anaerobic power test (WAnT) performed on a cycle ergometer. Thirty-two recreationally active men and women (22.4 ± 2.8 yrs; 1.73 ± 0.08 m; 74. 2 ± 13.2 kg) performed four familiarization trials on cTM, followed by two randomly assigned experimental trials consisting of one 30-second maximum effort on either cTM or WAnT. Each trial was separated by at least 48 hours. Repeated measures analysis of variance (ANOVA), interclass correlations (ICC), standard error of measurement (SEM), and minimal differences (MD) were used to determine reliability of familiarization trials on cTM, and Pearson product moment correlations were calculated to compare cTM and WAnT. ANOVA results showed significant differences (p < 0.05) during the four familiarization trials. Post hoc analysis showed significant differences (p < 0. 05) between the first two trials. Familiarization trials 3 and 4 showed a high reliability for each performance variable (distance: ICC2,1 = 0.969, %SEM = 2.645, p = 0.157; mean velocity: ICC2,1 = 0. 969, %SEM = 2.622, p = 0.173; peak velocity: ICC2,1 = 0.966, %SEM = 3.142, p = 0.033; mean power: ICC2,1 = 0.940, %SEM = 4.140, p = 0.093; and peak power: ICC2,1 = 0.887, %SEM = 11.244, p = 0.669). Participants elicited an average peak power of 1050.4 ± 338.5 Watts on cTM and 1031.4 ± 349.8 Watts on WAnT. Pearson product moment coefficients indicated high correlations between peak power, mean power, and peak velocity (r = 0.75, p < 0.001; r = 0.84, p < 0.001; and r = 0.76, p < 0. 001, respectively) derived from cTM and WAnT. In conclusion, results suggest that after two familiarization trials, cTM is a reliable sprint test for recreationally active men and women. In addition, there are strong relationships between cTM and WAnT in assessing anaerobic performance. Key pointsThe Woodway Curve 3.0(TM) is a non-motorized treadmill utilizing a curved platform which allows individuals to simulate an unrestricted sprint test in a laboratory setting, offering a practical and sport specific method of assessing anaerobic power.The curved treadmill provides a reliable sprint test for recreationally active men and women.There are strong relationships between the curved treadmill and cycle ergometer in assessing anaerobic performance.
The measurement of human power output and anaerobic capacity in high-intensity exercise has traditionally been made using cycle ergometers. The assessment of power output during running has proved difficult because previous approaches have limited themselves to using motorized treadmills. In the present study the problems associated with motorized treadmills were overcome by using a non-motorized treadmill which was instrumented so as to allow the measurement of power output during sprint running. A non-motorized treadmill (Woodway model AB) was used because it allows rapid changes in running velocity normally found in sprinting to be monitored. In order to calculate the horizontal component of the applied power the instantaneous values of both the horizontal component of applied force and the treadmill belt speed were measured, and their product determined. A harness, attached to a force transducer, was passed around the waist securing the subject to the crossbar without restricting the movement of the limbs. The force measured was assumed to be the same as that horizontally applied to the treadmill belt.The outputs from the speed detector, force transducer and heart rate monitor were continuously monitored by a microcomputer.The results of the study showed that:(1)the peak speed attained on the treadmill is approximately 80% of that achieved in free-sprinting.(2)peak force is attained earlier than peak power and in turn peak power occurs before peak speed.(3)the force and power required to propel the treadmill belt at a constant speed increase with body weight.(4)the power required to propel the treadmill belt increases with speed.(5)stride length and frequency could be monitored.(6)elasticity in the tethering system acted as a low pass filter on the force profile.
The reproducibility of performance in a laboratory test impacts on the statistical power of that test to detect changes of performance in experiments. The purpose of this study was to determine the reproducibility of performance of distance runners completing a 60 min time trial (TT) on a motor-driven treadmill. Eight trained distance runners (age 27 +/- 7yrs, peak oxygen consumption [VO2peak] 66 +/- 5 ml x min(-1) x kg(-1), mean +/- SD) performed the TT on three occasions separated by 7-10 days. Throughout each TT the runners controlled the speed of the treadmill and could view current speed and elapsed time, but they did not know the elapsed or final distance. On the basis of heart-rate, it is estimated that the subjects ran at an average intensity equivalent to 80-83% of VO2peak. The distance run in 1 h did not vary substantially between trials (16.2 +/- 1.4 km, 15.9 +/- 1.4 km, and 16.1 +/- 1.2 km for TTs 1-3 respectively, p = 0.5). The coefficient of variation (CV) for individual runners was 2.7% (95% Cl = 1.8-4.0%) and the test-retest reliability expressed as an intraclass correlation coefficient was 0.90 (95% Cl = 0.72-0.98). Reproducibility of performance in this test was therefore acceptable. However, higher reproducibility is required for experimental studies aimed at detecting the smallest worthwhile changes in performance with realistic sample sizes.
Previous research has suggested elite Australian footballers undertake pacing strategies to preserve high intensity activity later in matches. However, this research used GPS with slow sample rates, did not express performance relative to minutes played during games and used lowly ranked players.
Therefore in this study movement was recorded by GPS at 5 Hz. Running performance was expressed per period of the match (rotation) divided into low-intensity activity (LIA, 0.10 to 4.17 m x s(-1)); high-intensity running (HIR, 4.17 to 10.00 m x s(-1)) and maximal accelerations (2.78 to 10.00 m x s(-2)). All data were expressed relative to the first period of play in the match and the magnitude of effects was analyzed with the effect size (ES) statistic and expressed with confidence intervals.
The total and LIA distance covered by players did not change by a practically important magnitude during games (ES< 0.20). High intensity running was reduced in both rotations of the second quarter, Q3R2 and both rotations of the fourth quarter (ES -0.30 ± 0.14; -0.42 ± 0.14; -0.30 ± 0.14; -0.42 ± 0.14; and -0.48 ± 0.15 respectively). Maximal acceleration performance was reduced in Q1R2, and each rotation of the second half of matches.
When expressed per minute of game time played, total distance and low intensity activity distance are not reduced by a practically important magnitude in AF players during a match. These data are therefore inconsistent with the concept of team sport players pacing their effort during matches. However, both high intensity running and maximal accelerations are reduced later in games, indicative of significant fatigue in players.
This study examined differences in movement patterns between AFL (elite) and WAFL (sub-elite) players using Global Positioning System (GPS) devices. Maximum speed data and totals of high intensity efforts (>15 km h⁻¹), sprint efforts (>20 km h⁻¹) and distance covered were collected on 41 players during the 2008 season. Data were expressed per min of game time played, separated into first and second halves, and also into positions, for both elite and sub-elite players. Overall, elite players had higher movement demands, including 9% more distance covered/min (128±12 m min⁻¹ vs. 117±15 m min⁻¹; p<0.01, ES=0.84), and 21% more high intensity efforts/min (2.9±0.6 vs. 2.4±0.6; p<0.01, ES=0.83). Movement demands significantly declined (p<0.05-0.01) from first to second half, in both competition levels. For both leagues, Small Forwards/Small Backs and Midfield players covered significantly greater (p<0.05-0.01) total distances and completed more high intensity efforts than other positions. Ruckmen recorded significantly lower (p<0.05-0.01) movement demands than Small Forwards/Small Backs, Midfielders and Centre Half-Forwards/Centre Half-Backs over most variables. In conclusion, elite players recorded higher overall movement demands than sub-elite players. This information may be useful for coaches and conditioning staff in designing appropriate training drills for specific role requirements of individual players and assist in the progression of players from sub-elite to elite levels of competition.
The aim of this study was to determine the validity and reliability of a 90-minute soccer performance test: Ball-sport Endurance and Sprint Test (BEAST90). Fifteen healthy male amateur soccer players participated and attended 5 testing sessions over a 10-day period to perform physiologic and soccer-specific assessments. This included familiarization sessions and 2 full trials of the BEAST90, separated by 7 days. The total 90-minute distance, mean percent peak heart rate (HRpeak), and estimated percent peak oxygen uptake of the BEAST90 were 8,097 ± 458 m, 85 ± 5% and 82 ± 14%, respectively. Measures obtained from trial 1 and trial 2 were not significantly different (p > 0.05). Reliability of measures over 90 minutes ranged from 0.9-25.5% (% typical error). The BEAST90 protocol replicated soccer match play in terms of time, movement patterns, physical demands (volume and intensity), distances, and mean and HRpeak values, as well as having an aerobic load similar to that observed during a soccer match. Reproducibility of key physical measures during the BEAST90 were mostly high, suggesting good reliability. The BEAST90 could be used in studies that wish to determine the effects of training or nutritional interventions on prolonged intermittent physical performance.
The purpose of the study was to assess the reliability and validity of a newly developed laboratory protocol to measure prolonged repeated-sprint ability (RSA) during soccer-specific exercise.
To assess reliability, 12 youth soccer players age 15.2 +/- 0.3 y performed 2 trials of a soccer-specific intermittent-exercise test (SSIET) separated by 3 months. The test was performed on a nonmotorized treadmill. A separate sample of 12 youth soccer players (15.2 +/- 0.3 y) completed the SSIET while simultaneously HR, VO2, and blood lactate (BLa) were monitored. The SSIET was designed to replicate the demands of competing in one half of a soccer match while sprint performance was monitored. The test included a 5-s sprint every 2 min.
The mean coefficient of variation was 2.5% for the total distance covered during the SSIET and 3.8% for the total distance sprinted; measures of power output were less reliable (=5.9%). Participants covered 4851 +/- 251 m during the SSIET, working at an average intensity of 87.5% +/- 3.2% HRpeak and 70.2% +/- 3.1% VO2peak, with ~7mmol/L BLa accumulation. A significant reduction (P < .05) in sprint performance was observed over the course of the SSIET.
The SSIET provided a reliable method of assessing prolonged RSA in the laboratory. The distance covered and the physiological responses during the SSIET successfully recreated the demands of competing in a soccer match.
1. The relation of V̇ O2 and speed was determined on six competition cyclists riding at speeds ranging from 12 km/hr to 41 km/hr on the runway of an airfield. Comparative measurements were made on the bicycle ergometer to determine the corresponding work rates, and from this information rolling resistance and air resistance were derived.
2. V̇ O2 was a curvilinear function of cycling speed, and increased from 0·88 l./min at 12·5 km/hr to 5·12 l./min at 41 km/hr, mean body weight being 72·9 kg.
3. On the ergometer, V̇ O2 was a linear function of work rate; maximum values up to 5·1 l./min (74·4 ml./kg min) and work rates up to 425 W (2600 kg m/min) were observed.
4. Data are presented on the relation of pedal frequency and speed in cycling, and on the relation of mechanical efficiency and pedal frequency, as determined on the ergometer.
5. The estimated rolling resistance for four subjects was 0·71 kg f. The drag coefficient was 0·79 and the drag area 0·33 m ² . The values agreed well with results obtained by other methods.
6. The energy expenditure (power developed) in cycling increased approximately as the square of the speed, and not as the cube of the speed as expected. This was explained by the varying contribution of rolling resistance and air resistance to over‐all resistance to motion at different speeds.
Endurance performance is a common criterion used to evaluate training or dietary interventions. However, to accurately appraise the effects of an intervention, the endurance performance measure must be reliable. The purpose of the investigation was to establish the reliability of a 1-h endurance performance test. Twenty trained female subjects (peak VO2 = 47.4 +/- 7.2 ml.kg-1.min-1) completed two trials in which they had to generate the highest power output possible throughout 60 min of cycling. Heart rates (HR) and ratings of perceived exertion (RPE) were also recorded during these two trials. All tests were conducted on a wind-braked cycle ergometer set up to closely resemble the subject's own cycle. The trials were separated by 1 wk, conducted on the same day of the week, and completed at a similar time of the day. The average power outputs (+/-SD) for the two trials were 180.0 (+/-18.1) W and 180.0 (+/-20.6) W. The results revealed that average absolute power output, HR, and RPE were not significantly different between trials. The intraclass correlation coefficient (one way ANOVA) for average absolute power output was 0.97, the coefficient of variation was 2.7%, and the SEM was 3.4 W. These results suggest that under controlled conditions average absolute power output during a 1-h endurance test is a reliable measure for trained female cyclists.
Reliability refers to the reproducibility of values of a test, assay or other measurement in repeated trials on the same individuals. Better reliability implies better precision of single measurements and better tracking of changes in measurements in research or practical settings. The main measures of reliability are within-subject random variation, systematic change in the mean, and retest correlation. A simple, adaptable form of within-subject variation is the typical (standard) error of measurement: the standard deviation of an individual's repeated measurements. For many measurements in sports medicine and science, the typical error is best expressed as a coefficient of variation (percentage of the mean). A biased, more limited form of within-subject variation is the limits of agreement: the 95% likely range of change of an individual's measurements between 2 trials. Systematic changes in the mean of a measure between consecutive trials represent such effects as learning, motivation or fatigue; these changes need to be eliminated from estimates of within-subject variation. Retest correlation is difficult to interpret, mainly because its value is sensitive to the heterogeneity of the sample of participants. Uses of reliability include decision-making when monitoring individuals, comparison of tests or equipment, estimation of sample size in experiments and estimation of the magnitude of individual differences in the response to a treatment. Reasonable precision for estimates of reliability requires approximately 50 study participants and at least 3 trials. Studies aimed at assessing variation in reliability between tests or equipment require complex designs and analyses that researchers seldom perform correctly. A wider understanding of reliability and adoption of the typical error as the standard measure of reliability would improve the assessment of tests and equipment in our disciplines.
The aim of this study was to devise a laboratory-based protocol for a motorized treadmill that was representative of work rates observed during soccer match-play. Selected physiological responses to this soccer-specific intermittent exercise protocol were then compared with steady-rate exercise performed at the same average speed. Seven male university soccer players (mean ± s: age 24 ± 2 years, height 1.78 ± 0.1 m, mass 72.2 ± 5.0 kg, V̇O(2max) 57.8 ± 4 ml/kg-1/min-1) completed a 45-min soccer-specific intermittent exercise protocol on a motorized treadmill. They also completed a continuous steady-rate exercise session for an identical period at the same average speed. The physiological responses to the laboratory-based soccer-specific protocol were similar to values previously observed for soccer match-play (oxygen consumption approximately 68% of maximum, heart rate 168 ± 10 beats/min-1). No significant differences were observed in oxygen consumption, heart rate, rectal temperature or sweat production rate between the two conditions. Average minute ventilation was greater (P < 0.05) in intermittent exercise (81.3 ± 0.2 l/min-1) than steady-rate exercise (72.4 ± 11.4 l/min-1). The rating of perceived exertion for the session as a whole was 15 ± 2 during soccer-specific intermittent exercise and 12 ± 1 for continuous exercise (P < 0.05). The physiological strain associated with the laboratory-based soccer-specific intermittent protocol was similar to that associated with 45 min of soccer match-play, based on the variables measured, indicating the relevance of the simulation as a model of match-play work rates. Soccer-specific intermittent exercise did not increase the demands placed on the aerobic energy systems compared to continuous exercise performed at the same average speed, although the results indicate that anaerobic energy provision is more important during intermittent than during continuous exercise at the same average speed.
The purpose of this study was to assess the reliability of a repeated-sprint test, specifically designed for field-hockey, as it was based directly on the time-motion analysis of elite level competition. The test consisted of 6 x 30-m over-ground sprints departing on 25s, with an active recovery (approximately 3.1-3.3 ms(-1)) between sprints. Ten highly trained, male, field-hockey players (mean+/-S.D.: age, 23+/-3 years; body mass, 78.1+/-7.1 kg) participated in this study. Following familiarisation, the subjects performed the repeated-sprint test on two occasions, 7 days apart. The reliability of the test variables was assessed by the typical error of measurement (TE). The total sprint time was very reliable (T(1): 26.79+/-0.76 s versus T2: 26.83+/-0.74 s), as the TE was 0.7% (95% CL, 0.5-1.2%). However, the percent sprint decrement was less reliable (T1: 5.6+/-0.9% versus T2: 5.8+/-1.0%), with the TE being 14.9% (95% CL, 10.8-31.3%). In summary, it is suggested that this field-hockey-specific, repeated-sprint test is very reliable when the results are presented as the total sprint time.
A large number of team sports require athletes to repeatedly produce maximal or near maximal sprint efforts of short duration interspersed with longer recovery periods of submaximal intensity. This type of team sport activity can be characterized as prolonged, high-intensity, intermittent running (PHIIR). The primary purpose of the present study was to determine the physiological factors that best relate to a generic PHIIR simulation that reflects team sport running activity. The second purpose of this study was to determine the relationship between common performance tests and the generic PHIIR simulation. Following a familiarization session, 16 moderately trained (VO2max = 40.0 +/- 4.3 ml x kg(-1) x min(-1)) women team sport athletes performed various physiological, anthropometrical, and performance tests and a 30-minute PHIIR sport simulation on a nonmotorized treadmill. The mean heart rate and blood lactate concentration during the PHIIR sport simulation were 164 +/- 6 b x min(-1) and 8.2 +/- 3.3 mmol x L(-1), respectively. Linear regression demonstrated significant relationships between the PHIIR sport simulation distance and running velocity attained at a blood lactate concentration of 4 mmol x L(-1) (LT) (r = 0.77, p < 0.05), 5 x 6-second repeated cycle sprint work (r = 0.56, p < 0.05), 30-second Wingate test (r = 0.61, p < 0.05), peak aerobic running velocity (Vmax) (r = 0.69, p < 0.05), and Yo-Yo Intermittent Recovery Test (Yo-Yo IR1) distance (r = 0.50, p < 0.05), respectively. These results indicate that an increased LT is associated with improved PHIIR performance and that PHIIR performance may be monitored by determining Yo-Yo IR1 performance, 5 x 6-second repeated sprint cycle test work, 30-second Wingate test performance, Vmax, or LT. We suggest that training programs should focus on improving both LT and Vmax for increasing PHIIR performance in moderately trained women. Future studies should examine optimal training methods for improving these capacities in team sport athletes.
The aim of this study was to determine the reliability of a non-motorised treadmill team-sport simulation for measuring physiological responses and performance demands of team sports. Following familiarisation, 11 team-sport athletes completed a peak sprinting speed assessment followed by a 30-min team-sport simulation on the non-motorised treadmill, on three occasions, 5 days apart. Several performance (total distance, distance covered during each speed category, total work, high-intensity activity, mean maximal sprinting speed and power) and physiological variables (V(O)(2), heart rate and blood measures) were measured. A one-way analysis of variance and ratio limits of agreement were used to compare the results from each trial. Significant differences were established in total sprint distance and high-intensity activity between trials 1-2 and trials 1-3 and 3-s mean maximal sprinting speed for trials 1-3 (p<0.05). No other significant differences were identified. Moderate to high intraclass correlation coefficients (i.e., >0.8) were identified in 11 of the 18 physiological and performance variables measured. Ratio limits of agreement for total distance covered and total work performed during the team-sport simulation were 0.99 (*//1.05) and 0.97 (*//1.09), respectively. Largest measurement error was shown in post-exercise blood lactate concentration with a coefficient of variation of 17.6%. All other measures showed low coefficients of variation of < or = 10%. These results show that the non-motorised treadmill team-sport simulation provides a reliable tool for assessing and monitoring physiological and performance demands of team-sport activity. We recommend the inclusion of two familiarisation sessions prior to testing.