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Abstract

It has been suggested that the uniquely large gluteus maximus (GMAX) muscles were an important adaptation during hominin evolution based on numerous anatomical differences between humans and extant apes. GMAX electromyographic (EMG) signals have been quantified for numerous individual movements, but not across the range of locomotor gaits and speeds for the same subjects. Thus, comparing relative EMG amplitudes between these activities has not been possible. We assessed the EMG activity of the gluteal muscles during walking, running, sprinting, and climbing. To gain further insight into the function of the gluteal muscles during locomotion, we measured muscle activity during walking and running with external devices that increased or decreased the need to control either forward or backward trunk pitch. We hypothesized that 1) GMAX EMG activity would be greatest during sprinting and climbing and 2) GMAX EMG activity would be modulated in response to altered forward trunk pitch demands during running. We found that GMAX activity in running was greater than walking and similar to climbing. However, the activity during sprinting was much greater than during running. Further, only the inferior portion of the GMAX had a significant change with altered trunk pitch demands, suggesting that the hip extensors have a limited contribution to the control of trunk pitch movements during running. Overall, our data suggest that the large size of the GMAX reflects its multifaceted role during rapid and powerful movements rather than as a specific adaptation for a single submaximal task such as endurance running. Am J Phys Anthropol, 2013. © 2013 Wiley Periodicals, Inc.

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... However, as seen in Table-1, each surgical approach uses different muscular and inter-nervous interval, which may result in approach-specific direct trauma (via incision, detachment, or retraction) or indirect trauma by injury to the nerve supply or damage to other surrounding structures, potentially leading to musculoskeletal dysfunction [16][17][18][19][20][21][22][23][49][50][51] . Thus, based on the approach, other muscles like Gluteus Maximus (GMax), Rectus Femoris, Obturators which are well documented to have multiple functions as movement stabilizers or movement facilitators at the hip, knee, pelvis, and trunk, during activities such as standing, walking, stairs, squats, may also potentially be affected [52][53][54][55][56][57][58] . This presents the possibility of other hip movements like extension, flexion, and rotation being compromised during THA. ...
... However, variations in measurement tools, methodology, and test positions used in THA research make the extrapolation of results and comparison of muscle strength outcomes complex. A variety of methods, including the Medical Research Council scale rating, manual muscle testing, handheld or isokinetic dynamometry, or other customized devices, has been used to quantify muscle strength in literature [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85] . Substantial variability is also seen in the reporting of strength outcomes with the results expressed as raw numbers, values normalized to limb-length or the contralateral side, and strength or torque ratios to the non-operated side [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85] . ...
... A variety of methods, including the Medical Research Council scale rating, manual muscle testing, handheld or isokinetic dynamometry, or other customized devices, has been used to quantify muscle strength in literature [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85] . Substantial variability is also seen in the reporting of strength outcomes with the results expressed as raw numbers, values normalized to limb-length or the contralateral side, and strength or torque ratios to the non-operated side [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85] . These factors contribute to the challenge of obtaining clinically meaningful information from the conducted research. ...
Article
Full-text available
Background: Persistent functional abnormalities and strength deficits are commonly reported despite the advances in surgical approaches for primary total hip arthroplasty (THA). Understanding the influence of different approaches on hip muscle strength changes following THA may play a crucial role in optimizing post-operative recovery. Aim: Systematic review and meta-analysis of between-approach comparison of directly measured hip muscle strength following primaryTHA. Method: A comprehensive online database search was performed, identifying studies that compare muscle strength between at least two different THA approaches. Based on Cochrane guidelines, a qualitative and quantitative analysis was completed along with a meta-analysis of the eligible studies. ROBINS-i and ROB-2 were used to analyse the risk of bias, and the Pedro tool was used for quality appraisal. Results: 881 publications were appraised, yielding 23 eligible publications. Sufficient data for analysis was found only between posterior and lateral approaches for hip abduction strength in all categories. No statistically significant difference was found between the two approaches at 12 months and over time-period following THA (Z=1.51, P=0.13, Std Mean diff = 0.24, 95% CI [-.07,.56]). However, the results slightly favoured posterior approach. Additionally, no statistically significant difference found in the strength ratio of the operated side to the unoperated side (U = 15, z = -0.52, p = 0.69) or in the percentage change in muscle strength at 3 months (U=10, z=-.577, p=0.686) and 12 months (U = 10, z=-.577, p = 0.686) from pre-operative baseline. Conclusion: This systematic review and meta-analysis found no statistically significant difference between posterior and lateral approaches for directly measured hip muscle strength measured. Despite the increasing popularity of AA, ALA, and other minimally invasive or modified approaches, and the relationship between muscle strength and function, a sparsity was identified in published studies that performed a comparison between approaches of hip muscle strength.
... However, if the hip extensor muscles are underdeveloped, their involvement in such activities are diminished (Beardsley & Contreras, 2014;Stearns & Powers, 2014;Stearns et al., 2013). This may create situations where an individual is more likely to underperform and/or be more prone to knee injuries or lower back pain (Bartlett et al., 2014;Hossain & Nokes, 2005;Lane & Mayer, 2017;Mayer et al., 2010). The classification of muscles known as the hip extensors are composed of a group of agonistic muscles, which is divided into two subcategories, primary and secondary hip extensors. ...
... Therefore, the purpose of this research was to determine differences in lower body muscular activity between the BHT and the BGB at 5-repetition maximum (5-RM). Further, given previous research demonstrates different muscle segments within the GMax (cranial, middle, and caudal) are meant to perform specific roles in various tasks, such as postural or dynamic activities (McAndrew et al., 2006;Stern, 1972) the GMax was further subdivided into the upper GMax (UGMax) and lower GMax (LGMax), similar to previous gluteal muscle research (Bartlett et al., 2014). Therefore, it was hypothesised the BHT would elicit significantly greater LGMax, GMed, BF, and vastus lateralis (VL) activity than the BGB. ...
... Experimental Approach to the Problem: To explore the purpose of this study, a five site surface electromyography (sEMG) was utilised to record electrical muscular activity of the UGMax, LGMax, GMed, BF, and VL. Following the protocol of previous research (Bartlett et al., 2014;Fujisawa et al., 2014;Hermens et al., 2000) the positioning of the sEMG were directly over the 'belly' of the muscle. The electrical muscular activity was measured during a 5-repetition maximum (5-RM) load performance for both the BHT and BGB exercises. ...
Article
Full-text available
Hip extensor muscles are critical to sport performance as events requiring sprinting and forceful landings are highly dependent on these muscles. Despite biomechanical differences between the barbell hip thrust (BHT) and the barbell glute bridge (BGB), both are biomechanically efficient ways to load this musculature for training purposes. Research investigating the differences in muscular activity between the BHT and BGB has yet been conducted. The aim of this study was to investigate, through surface electromyography, if one exercise is more optimal than the other in producing greater muscle activation for specific hip extensor muscles. Ten male participants completed a two-part study protocol. Results revealed the BHT elicited significantly greater muscle activity within the vastus lateralis for peak and mean outcomes; however, the BGB elicited significantly greater muscle activity in the upper and lower gluteus maximus for peak and mean outcomes and mean outcome in the gluteus medius. Current findings suggest, the BGB is, at minimum, a superior substitute for the BHT for eliciting a larger magnitude of activity in the gluteus maximus. Future studies between the two exercises are warranted to discern which produces greater hypertrophy and whether adaption of the BHT or BGB transfers more optimally to sport performance.
... A high content of IMF has been linked mainly to aging/sarcopenia 3-8 , but also to muscular 9,10 and physiological pathologies 11-15 and low levels of physical activity 16 . IMF accumulation has been mainly evaluated in the thigh 2,4,5,7,10,16-21 and calf muscles 3,16,22 , while the hip muscles have been overlooked despite their fundamental role in running, walking, standing and other human daily activities 23,24 . In the small number of studies looking at this muscle group, fatty infiltration in the glutei was found in patients with diseased hips 25,26 and was also correlated with accidental falls in elderly people 19,27 . ...
... In the small number of studies looking at this muscle group, fatty infiltration in the glutei was found in patients with diseased hips 25,26 and was also correlated with accidental falls in elderly people 19,27 . Of the gluteal muscles, gluteus maximus (GMAX) is particularly involved in physically demanding activities, such as in running, climbing or lifting 24,28,29 . However, to the best of our knowledge, GMAX fat content has not been studied for different levels of activity, including demanding physical tasks such as endurance running. ...
... In only one case, fatty atrophy of the gluteal muscles was reported. All the patients completed the Oxford Hip Score (OHS) questionnaire 31 and their hip dysfunction was graded as Severe (scores 0- 19), Moderate (20)(21)(22)(23)(24)(25)(26)(27)(28)(29), Mild (30)(31)(32)(33)(34)(35)(36)(37)(38)(39) and Satisfactory (40)(41)(42)(43)(44)(45)(46)(47)(48) as recommended in the OHS system. We used these grades as a measure of the degree of hip pain. ...
Article
Full-text available
We aimed to determine if gluteus maximus (GMAX) fat infiltration is associated with different levels of physical activity. Identifying and quantifying differences in the intramuscular fat content of GMAX in subjects with different levels of physical activity can provide a new tool to evaluate hip muscles health. This was a cross-sectional study involving seventy subjects that underwent Dixon MRI of the pelvis. The individuals were divided into four groups by levels of physical activity, from low to high: inactive patients due to hip pain; and low, medium and high physical activity groups of healthy subjects (HS) based on hours of exercise per week. We estimated the GMAX intramuscular fat content for each subject using automated measurements of fat fraction (FF) from Dixon images. The GMAX volume and lean volume were also measured and normalized by lean body mass. The effects of body mass index (BMI) and age were included in the statistical analysis. The patient group had a significantly higher FF than the three groups of HS (median values of 26.2%, 17.8%, 16.7% and 13.7% respectively, p < 0.001). The normalized lean volume was significantly larger in the high activity group compared to all the other groups ( p < 0.001, p = 0.002 and p = 0.02). Employing a hierarchical linear regression analysis, we found that hip pain, low physical activity, female gender and high BMI were statistically significant predictors of increased GMAX fat infiltration.
... The attributes that underpin physical performance are of course movement specific and require a combination physical and biomechanical variables in coordination to ascertain success. In this case, movement kinetics can describe the internal and external force contribution towards movement and movement kinematics seek to explain the motion of Bartlett et al., 2013). Therefore, it could be said that hip extension is crucial for acceleration and maximal sprinting performance. ...
... During sprint-acceleration the hip joint extends throughout the entire stance phase which allows for a great potential for hip extension torque. As previously alluded, this potential torque may become even more relied upon as action intensity increases (Beardsley & Contreras, 2014; Bartlett et al., 2013). Hip extension also seems to be the only joint action of the lower limb that doesn't shift dominance from a concentric to isometric/eccentric action as acceleration turns to maximum-velocity sprinting (Wild et al., 2015). ...
... In addition, as running speeds progress from 3.5 and 9.0 ms -1 a 304% increase in total hip extensor activity has been found (Schache et al., 2011), which has been said to partly explain the increase in force production (Kyröläinen et al., 1999). The sEMG activity of the Gmax in particular increases 5-fold from walking to a sprint (Bartlett et al., 2013) where it functions heavily during ground contact to reproduce accelerative horizontal forces against the floor (Bartlett et al., 2013). In addition, hamstring sEMG kinetics are seen to increase alongside running intensity (Chumanov et al., 2007;Higashihara et al., 2010) but are greatest in the late-swing phase (Chumanov et ...
Thesis
***For a copy of this full text please send a private message on research gate to Tom King.*** _____________________________________________________________________________________ Hip extension is a joint action that contributes to athletic movement during performance in various sports. Within the sport of professional soccer, high intensity efforts encompass an important proportion of athletic movement and optimal hip extensor functioning can be seen as a crucial action for the successful performance of such actions. Perhaps related to the importance placed upon high intensity efforts in soccer, the number of hamstring strain injuries that occur are of major concern to practitioners within the field. As such, great efforts are made to establish methods of managing and mitigating these injuries, one of which being improving hip extension function. Methods of establishing an individual’s maximal hip extension strength capacity are available yet are not void of several clinical and practical limitations. As such, understanding the relationship between the specific ability of hip extension with performance and injury related measures are difficult to investigate. Therefore, it may be of use to investigate the development of new strength assessment methods. _____________________________________________________________________________________ In study 1 (chapter 3) a framework of considerations was outlined that surround various methodological and theoretical concepts believed to influence the subsequent validity, reliability and operational success of hip extension assessment tools in the applied field. These considerations arose from information in previous scientific research and from the research team’s (PhD candidate and supervisors) wealth of experience working in applied professional sport. Throughout the framework of considerations, the assessment tools currently available for hip extension strength were critiqued and a rationale for the development of a new tool was outlined. Further into the chapter the adherence of these considerations was presented throughout the development of a new assessment tool (Hip Extension Bench). Finally, the ultimate section of this chapter then introduced information surrounding practical application of the Hip Extension Bench. _____________________________________________________________________________________ In study 2 (chapter 4) the sensitivity of the Hip Extension Bench was investigated where the research team assessed muscle activity and force changes in response to various hip flexion positions. The investigations were undertaken with a mixed population of elite soccer players (n = 10), competitive sprinters (n = 10) and recreationally active males (n = 5) and consisted of assessment across 6 different hip positions (70, 60, 45, 30, 15 and 0 hip flexion). Results displayed precise and specific changes in individual hip extensor muscle activity and force production under maximal isometric contractions at different hip joint angles. Gluteus maximus muscle peak activity was pronounced at positions of inner range hip flexion (0 and 15 deg) whereas maximum force and biceps femoris long head and semitendinosus peak activity was pronounced at positions of greater hip flexion (60 and 70 deg). These data suggest that the Hip Extension Bench can be manipulated to selectively target specific hip extensor muscles and careful precisions must be adhered to upon assessment setup to confirm standardised conditions. _____________________________________________________________________________________ In study 3 (chapter 5) the test-retest reliability of the Hip Extension Bench under non- fatigued conditions was investigated. A group of 40 elite youth soccer players and 15 competitive sprinters undertook maximal isometric hip extension contractions at two angles (15 and 60 deg) on two occasions with a minimum and maximum of 7 and 14 days between test days. Generally, both cohorts demonstrated good reliability of bilateral and unilateral isometric hip extension strength assessments. The findings also demonstrated the difficulties surrounding data collection in the applied field where several complications may arise that influence the subsequent findings and informed decisions that are made on reflection of the data. _____________________________________________________________________________________ In study 4 (chapter 6) the first implementation of the Hip Extension Bench within research surrounding isometric hip extension strength and sprint-acceleration and jump performance associations was presented. A sample of 10 competitive sprinters completed a minimum of three 40 m sprints on test day 1 and a comprehensive battery of strength and power assessments on test day 2 with a minimum and maximum of 7 and 14 days between each test day. The main findings confirmed that isometric hip extension strength was highly correlated with several force-based variables of sprint-acceleration performance (theoretical maximum force; F0, total force; FT Peak, total force across distances of 2, 20 and 40 m; FT 2, 20 & 40 m, mean horizontal force; FH Mean, horizontal force across distances of 2 and 20 m; FH 2 & 20 m and peak power; Pmax) and jump performance in the horizontal direction (the sum of left and right leg horizontal countermovement jumps; UL HCMJ Sum). These findings provide evidence for the role and importance of hip extension strength, specifically under isometric conditions, in high intensity effort performance. _____________________________________________________________________________________ Overall, these findings suggest that a new assessment tool for isometric hip extension strength has been developed that is suitable for application in the environment of applied professional sport. The findings also confirmed the important of hip extension for high intensity effort performance and in conclusion provide a strong rationale for the implementation of the Hip Extension Bench for future research and application in performance and injury management.
... The mechanics of hip extension in humans and apes also provide insight into the evolution of the gluteus maximus in hominins. In chimpanzees, orangutans, and gibbons, gluteus maximus is much smaller than in humans and does not extend the hamstrings' range of powered hip extension (34)(35)(36). In humans, the gluteus maximus is greatly enlarged and serves a distinct and complementary role with the hamstrings in powering hip extension. ...
... In human walking, hyperextension of the hip is powered in part by the hamstrings (ref. 26; Fig. 2 gluteus maximus is notably quiet throughout stance phase (34,35). Instead, the gluteus maximus is active when the hip is more flexed; for example, during the early portion of stance phase during running and climbing (34,35). ...
... 26; Fig. 2 gluteus maximus is notably quiet throughout stance phase (34,35). Instead, the gluteus maximus is active when the hip is more flexed; for example, during the early portion of stance phase during running and climbing (34,35). The enlarged gluteus maximus appears to compensate for humans' derived ischial morphology and the reduced effectiveness of the hamstrings when the hip is flexed, particularly at angles <40°, where the hamstrings cannot power extension (Fig. 2). ...
Article
The evolutionary emergence of humans’ remarkably economical walking gait remains a focus of research and debate, but experimentally validated approaches linking locomotor capability to postcranial anatomy are limited. In this study, we integrated 3D morphometrics of hominoid pelvic shape with experimental measurements of hip kinematics and kinetics during walking and climbing, hamstring activity, and passive range of hip extension in humans, apes, and other primates to assess arboreal–terrestrial trade-offs in ischium morphology among living taxa. We show that hamstring-powered hip extension during habitual walking and climbing in living apes and humans is strongly predicted, and likely constrained, by the relative length and orientation of the ischium. Ape pelves permit greater extensor moments at the hip, enhancing climbing capability, but limit their range of hip extension, resulting in a crouched gait. Human pelves reduce hip extensor moments but permit a greater degree of hip extension, which greatly improves walking economy (i.e., distance traveled/energy consumed). Applying these results to fossil pelves suggests that early hominins differed from both humans and extant apes in having an economical walking gait without sacrificing climbing capability. Ardipithecus was capable of nearly human-like hip extension during bipedal walking, but retained the capacity for powerful, ape-like hip extension during vertical climbing. Hip extension capability was essentially human-like in Australopithecus afarensis and Australopithecus africanus, suggesting an economical walking gait but reduced mechanical advantage for powered hip extension during climbing.
... One promising research area in measuring internal load can be represented by surface Electromyography (sEMG). It can be considered as an effective tool for measuring the internal response in terms of electrical activity during muscle contractions [14][15][16][17][18]. However, one of the major limitations to the use of this technology in field research is the operational challenge posed by the required instrumentation. ...
... This observed relationship is likely attributable to the augmented requirement for muscle recruitment and force generation necessary to achieve higher speeds. It is imperative to delve into the underlying mechanisms of this relationship and consider the potential contributing factors, including the response of the neuromuscular system to challenges associated with speed [15,17,18]. The intriguing uniformity in patterns that we have visualized and presented in Fig 1, exemplified by the interpolating lines, is particularly noteworthy. ...
Article
Full-text available
The purpose of this study is to investigate the relationship between speed and myoelectric activity, measured during an incremental 25m shuttle running test, exploring the time-based variations and assessing muscle group balance within the context of this association. Twelve male young soccer players (n = 12) aged 18±1.2 years, with an average body mass of 68.4±5.8kg and average body height of 1.72±0.08m, from a professional Italian youth team (Italian “Primavera”), volunteered as participants for this study. The speed of each player during testing was measured using GPS technology, sampling at 50Hz. Myoelectrical activities of the gluteus, hamstrings, and quadriceps muscles were recorded through wearable sEMG devices, sampled at 100Hz. To ensure alignment of the sampling frequencies, the sEMG data was resampled to 50Hz, matching the GPS data sampling rate. This allowed for direct comparison and analysis of the data obtained from both measurement systems. The collected data were then analyzed to determine the relationship between the investigated variables and any potential differences associated with different sides of the body. The results revealed a robust correlation (r²≈0.97) between the speed of the participants (m·s⁻¹) and their myoelectrical activity (μV) during the test. Factorial ANOVA 2x11 showed no significant differences between the sides of the analyzed muscles (p>0.05). The interpolation lines generated by the association of speed and sEMG exhibit very similar angular coefficients (0.9 to 0.12) in all six measurements obtained from electromyography of the three investigated muscle groups on each side of the body. In conclusion, the concurrent validity between the two instruments in this study indicates that GPS and sEMG are valid and consistent in estimating external load and internal load during incremental shuttle running.
... Weightlifting is a kind of sport which primarily requires lumbopelvic stability and dynamically uses all joints and striated muscles of the body (3)(4)(5). The gluteal muscles possess vital functions in standing, the stabilization of hip joint, ladder climbing, thigh and knee examination in lifting, sprinting, squatting, and climbing a steep hill (6)(7)(8). The gluteus maximus muscle (Gmax) originates at the iliac crest, sacrum, and coccyx, and inserts into the gluteal ridge at the postero-lateral femoral shaft below the greater trochanter (9,10). ...
... The gluteus maximus muscle (Gmax) originates at the iliac crest, sacrum, and coccyx, and inserts into the gluteal ridge at the postero-lateral femoral shaft below the greater trochanter (9,10). This muscle acts for the extension the hip joint, however, it can also act as adductor and lateral rotator of the lower limb and is active during locomotion (10,8,9). The mm. glutei medius (Gmed) and minimus (Gmin) muscles are referred to as small gluteal muscles (7). ...
Article
Full-text available
M. gluteus maximus is the most important extensor and lateral rotator of the hip. It is often used to accelerate the body upward and forward from a position of hip flexion. Mm. glutei medius and minimus are referred to as small gluteal muscles. Both muscles are the most important abductors and medial rotators of the thigh. Their action stabilises the hip during standing and walking and prevents the tilting of the pelvis to the contralateral side while standing on one leg. This study aims to examine the cross-sectional areas of the gluteus maximus, gluteus medius and gluteus minimus muscles on magnetic resonance images of olym-pic style weightlifting athletes (male n = 15, age: 20.00±2.54, height: 1.73±0.54 m, weight: 78.70±14.96 kg; female n = 12, age: 20.75±1.49, height: 1.60±0.64 m, weight: 57.37±8.30 kg) and sedentary individuals (male n = 15, age: 19.9±2.15, height: 1.74±0.53 m, weight: 79±15 kg; female n = 12, age: 20.75±1.36, height: 1.60±0.058 m, weight: 56.68±7.64 kg). The cross-sectional areas of the gluteus maximus, gluteus medius and gluteus minimus muscles were assessed bilaterally using magnetic resonance imaging. It was observed that the cross-sectional areas of the right and left gluteus maximus of male weightlifting athletes were larger than those of sedentary males (z(28)= 2.013, p< .05, z(28)= 1.991, p < .05; respectively). Similarly, it was also found that that the cross-sectional areas of the right and left gluteus maximus of female weightlifting athletes were larger than those of sedentary females (z(22)= 3.296, p< .001, z(22)= 3.726, p < .001; respectively). No significant difference was observed for the cross-sectional areas of the gluteus medius and gluteus minimus muscles between the athlete and sedentary groups (p>.05). It might be stated that olympic style weightlifting trainings have a hypertrophic effect on the cross-sectional area of the gluteus maximus muscle of the athletes.
... Studies by Bartlett et al. and Chumanov et al. showed that gluteal muscle activity increased with increasing running velocity (Bartlett, Sumner, Ellis, & Kram, 2014;Chumanov, Wille, Michalski, & Heiderscheit, 2012). Importantly, however, Bartletta et al., who assessed gluteal muscle activity during walking, running, sprinting and climbing a ladder, did not report significant changes in the increase in EMG signal amplitude between walking and running (Bartlett, Sumner, Ellis, & Kram, 2014). ...
... Studies by Bartlett et al. and Chumanov et al. showed that gluteal muscle activity increased with increasing running velocity (Bartlett, Sumner, Ellis, & Kram, 2014;Chumanov, Wille, Michalski, & Heiderscheit, 2012). Importantly, however, Bartletta et al., who assessed gluteal muscle activity during walking, running, sprinting and climbing a ladder, did not report significant changes in the increase in EMG signal amplitude between walking and running (Bartlett, Sumner, Ellis, & Kram, 2014). Significant changes in gluteus medius activity were only observed after the running speed changed. ...
Article
Many physiotherapists and motor preparation coaches recommend including resistance exercises for the hip joint abductors and external rotators in a warm-up. Muscle activation with resistance band exercises is believed to improve positional control of the pelvis and the lower limbs, thus reducing the risk of musculoskeletal injury during rehabilitation or training proper. The aim of this study was to assess the impact of a single session of activation of hip joint abductors and external rotators on gait and running parameters in healthy people. The study involved 54 healthy individuals aged 19-21 years. An experimental group (Group 1) performed a set of 6 resistance exercises with Thera rubber bands, intended to activate the hip joint abductors and external rotators. A control group (Group 2) performed the same set of exercises but without external resistance. A walking and running gait examination was performed on a Zebris FDM treadmill in both groups before and after the exercises. Both variants of exercises produced changes in selected gait parameters (p<0.05). An examination of running gait in Group 1 revealed an increase in step length in the dominant limb (p<0.05) and stride length (p<0.05) and step time in the dominant limb (p<0.05), stride length (p<0.05) and cadence (p<0.05). Heel pressure also decreased in both limbs, and heel pressure force decreased in the non-dominant limb (p<0.05). A running gait examination in Group 2 revealed increased midfoot pressure force in both limbs (p<0.05). Thus, a single session of exercises with resistance banding to activate the hip joint abductors and external rotators exerted an effect on running parameters, which may improve running economy.
... For example, two such studies focused specifically on gluteus maximus and reported that this muscle acts to extend the hip and control trunk flexion during the stance phase of running and sprinting. 15,16 A recent modelling study calculated lower-limb muscle forces for the first two foot contacts after block clearance and found that the ankle plantarflexors, soleus and gastrocnemius, contributed most of the GRF impulse generated at each step. 17 There are no data that describe how individual muscles work synergistically to increase the forward momentum of the body beyond the first two foot contacts of accelerated sprinting. ...
... They concluded that a major role of gluteus maximus is to extend the hip on the stance side to control trunk flexion during running. Bartlett et al. 15 found that gluteus maximus' activity during running at 5.3 m/s was much greater than at 3.0 m/s, but that only the inferior portion of this muscle responded to changes in trunk pitch velocity. These authors concluded that gluteus maximus has a limited role in controlling trunk flexion during running. ...
Article
Full-text available
We sought to provide a more comprehensive understanding of how the individual leg muscles act synergistically to generate a ground force impulse and maximize the change in forward momentum of the body during accelerated sprinting. We combined musculoskeletal modelling with gait data to simulate the majority of the acceleration phase (19 foot contacts) of a maximal sprint over ground. Individual muscle contributions to the ground force impulse were found by evaluating each muscle’s contribution to the vertical and fore-aft components of the ground force (termed ‘supporter’ and ‘accelerator/brake’, respectively). The ankle plantarflexors played a major role in achieving maximal-effort accelerated sprinting. Soleus acted primarily as a supporter by generating a large fraction of the upward impulse at each step whereas gastrocnemius contributed appreciably to the propulsive and upward impulses and functioned as both accelerator and supporter. The primary role of the vasti was to deliver an upward impulse to the body (supporter), but these muscles also acted as a brake by retarding forward momentum. The hamstrings and gluteus medius functioned primarily as accelerators. Gluteus maximus was neither an accelerator nor supporter as it functioned mainly to decelerate the swinging leg in preparation for foot contact at the next step. Fundamental knowledge of lower-limb muscle function during maximum acceleration sprinting is of interest to coaches endeavouring to optimize sprint performance in elite athletes as well as sports medicine clinicians aiming to improve injury prevention and rehabilitation practices.
... Therefore, protocols that stimulate more muscle groups should be incorporated. For example, in addition to using NMES in the lower extremity muscles mentioned above, it should also be considered to stimulate the upper extremity muscles or, in particular, for example, the gluteal muscles, due to its "multifunctional" role in human gait [52]. ...
... It is necessary to consider that the effectiveness of NMES is affected by a variety of factors, including the programmed parameters [17,18]. As variables to assess to achieve an adequate session of NMES Herzig and Maffiuletti (2015) suggest: the type of electrodes used, position of the electrodes, pulse duration and form, stimulation intensity, stimulation frequency, duty cycle or ON/OFF periods, position of the extremity, duration and frequency (number of times a day) of the electrical stimulation, in addition to considering the desired objectives with NMES (reduction of fatigue, increased muscle strength, among others) [52]. Table 1 provides a summary of the NMES protocols from the articles mentioned in this review. ...
Article
Background Skeletal muscle atrophy is a relevant and common problem in patients admitted to intensive care units (ICU). It is an imbalance between the muscle protein synthesis/degradation pathways and its onset is due to situations to which these patients are exposed, such as: disuse, corticoids, inflammatory cytokines, and others. Neuromuscular electrical stimulation (NMES) has been proposed as a safe and effective intervention. This review aims to establish the effectiveness of NMES in the modification of skeletal muscle mass/strength in critical patients and establish recommendations/limitations for its use in clinical practice. Methodology A review of the available literature on clinical trials was carried out in the following databases: Medline/Pubmed, Pedro, Central, Science Direct, Web of Science, Embase and CINAHL. Finally, seven articles were included in the review. The seven articles included were evaluated by two authors (PS and PG-V) according to the PEDro scale. Three of these were of high quality and four of moderate quality. Results NMES is a little used treatment strategy in practice, but it has demonstrated clinical and molecular benefits for the patients who pass through the ICU. Seven articles were included in the review and were evaluated according to the PEDro scale by two authors (PS and PG-V). NMES has demonstrated clinical and molecular benefits for the patients who pass through the ICU. Conclusion NMES added to conventional therapy in ICU patients has proven to be effective in improving skeletal muscle mass and strength. NMES protocols in critically ill patients should start early (at least 24 or 48 hours after admission) and stimulating large muscle groups (upper and lower extremities). The clinical stability and possible contraindications must also be borne in mind, even though adverse effects are rare.
... With regard to the GM, it is known to be a major muscle for performing hip extension because of the largest among the hip extensors [4,18]. Tayashiki et al. [19] reported a positive correlation between the GM thickness and hip extensor maximal torque, but this correlation did not reach significance. ...
... Tayashiki et al. [19] reported a positive correlation between the GM thickness and hip extensor maximal torque, but this correlation did not reach significance. Moreover, Bartlett et al. [18] determined that an increase in the electromyographic activity of the GM is related to increased sprint velocity when sprinting. In addition, the GM plays an important role in decelerating the forward swing of the leg during the latter half of the swing phase and stabilizing the trunk against flexion while sprinting [17,20]. ...
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Objective The major purpose of this study was to determine the specific muscle(s) for superior sprint performance in sprinters. The cross sectional areas (CSAs) of ten muscles of the trunk and lower limb were measured using magnetic resonance images in 56 male sprinters and 40 male non-sprinters. In addition to the absolute CSA, to minimize the effect of difference in body size among participants, the relative CSA normalized to body mass was used for analysis of this study. Results Absolute and relative CSAs of most trunk and lower limb muscles, including the psoas major (PM) and gluteus maximus (GM), were significantly larger in sprinters than in non-sprinters (all P < 0.001, d = 0.91 to 1.82). The absolute and relative CSAs of the PM and GM correlated significantly with personal best 100-m sprint time in sprinters ( r = − 0.363 to − 0.388, all P < 0.01). A stepwise multiple regression analysis revealed that both CSAs of absolute PM and relative GM were predictive variables for the personal best 100 m sprint time in sprinters ( β = − 0.289 and − 0.287, respectively, both P < 0.05). These findings suggest that the PM and GM may be specific muscles for superior sprint performance in sprinters.
... The individual muscle peak normalized EMG amplitude for the stair descent was defined as the maximum amplitude for the stance phase during stair descent. EMG data were normalized to PEALW on the straightaways similarly to other studies which normalized EMG data of functional tasks to walking [35,36]. Based on the equation described by Winter [37], the magnitude of agonist-antagonist muscle co-activation was calculated as the overlapped EMG-signal area for agonist-antagonist EMG signals relative to the sum of each EMG signal area calculated for the total stance time. ...
... The electrode location can influence the quality of the signal [49]. In order to solve this position issue, this study used the electrode position previously suggested [35,36]. In addition, only the two-step staircase, installed before the stair-toground transition, was used in this experiment. ...
Article
The movement pattern during stair descent differs by gender, and this difference may be associated with gender differences in muscle strength or activation. The purpose of this study was to determine whether a gender difference in muscle activation exists by comparing the muscle activation amplitude and co-activation of lower extremity muscles during the stair-to-ground descent transition. Fifteen men and thirteen women descended stairs and the muscle activation was measured. Women showed a significantly lower peak normalized electromyography amplitude of the vastus lateralis (women: 171.7% peak EMG activation amplitude for level walking (PEALW), men: 297.0%PEALW, p < 0.05). Additionally, women showed significantly elevated co-activation of the vastus lateralis and biceps femoris compared to men (p < 0.05). The lower amplitude of the vastus lateralis in women indicates lower recruitment of knee extensor. In conclusion, the significantly higher co-activation of the vastus lateralis and biceps femoris in women may be a women’s stair descent strategy to safely descend stairs by increasing knee joint stability and stiffness through less recruitment of knee extensor muscle during stair-to-ground descent transition.
... At peak exercise, the percentage Q̇L EG of Q̇C was 69% and 74% of total Q̇C for running and cycling, respectively, and in agreement with previous work [25]. The small difference is acceptable given that the activation of the gluteus maximus, which drains proximally to the femoral vein, is generally greater during running exercise [26,27]. Considering the likely distribution of blood flow to the working respiratory muscles [28], we can appreciate a remarkable fraction of Q̇C is delivered to skeletal muscle during running exercise [29,30]. ...
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Cardiac output (Q̇C) and leg blood flow (Q̇LEG) can be measured simultaneously with high accuracy using transpulmonary and femoral vein thermodilution with a single‐bolus injection. The invasive measure has offered important insight into leg hemodynamics and blood flow distribution during exercise. Despite being the natural modality of exercise in humans, there has been no direct measure of Q̇LEG while running in humans. We sought to determine the feasibility of the thermodilution technique for measuring Q̇LEG and conductance during high‐intensity running, in an exploratory case study. A trained runner (30 years male) completed two maximal incremental tests on a cycle ergometer and motorized treadmill. Q̇LEG and Q̇C were determined using the single‐bolus thermodilution technique. Arterial and venous blood were sampled throughout exercise, with continuous monitoring of metabolism, intra‐arterial and venous pressure, and temperature. The participant reached a greater peak oxygen uptake (V̇O2peak) during running relative to cycling (74 vs. 68 mL/kg/min) with comparable Q̇LEG (19.0 vs. 19.5 L/min) and Q̇C (27.4 vs. 26.2 L/min). Leg vascular conductance was greater during high‐intensity running relative to cycling (82 vs. 70 mL/min/mmHg @ ~80% V̇O2peak). The “beat phenomenon” was apparent in femoral flow while running, producing large gradients in conductance (62–90 mL/min/mmHg @ 70% V̇O2peak). In summary, we present the first direct measure of Q̇LEG and conductance in a running human. Our findings corroborate several assumptions about Q̇LEG during running compared with cycling. Importantly, we demonstrate that using thermodilution in running exercise can be completed effectively and safely.
... Increases in running speed have been linked to increased muscle activations of all the lower limb muscle groups [18][19][20][21]. However, several studies specifically focused on a limited number of muscles (e.g., hamstrings or gluteals [20,22]), and no studies have assessed muscle activity alongside functional muscle group (or joint) specific kinetics during running at different speeds. Knowledge of how muscle activity and functional muscle group kinetics change may give a more thorough understanding of the muscular demands of running at different speeds. ...
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How the neuromechanics of the lower limb functional muscle groups change with running speed remains to be fully elucidated, with implications for our understanding of human locomotion, conditioning, and injury prevention. This study compared the neuromechanics (ground reaction and joint kinetics, kinematics and muscle activity) of middle‐distance athletes running on an instrumented treadmill at six wide‐ranging speeds (2.78–8.33 m·s⁻¹). Ground reaction forces and kinematics were analyzed using inverse dynamics to calculate flexor and extensor joint torques, and positive and negative work done by these torques. Contributions of each functional muscle group to the total positive and negative work done by the limb during stance, swing, and the whole stride were quantified. During stance, the ankle plantar flexors were the major energy generator and absorber (>60%) at all speeds, but their contribution to whole stride energy generation and absorption declined with speed. Positive work by the hip extensors rose superlinearly with speed during stance (3‐fold) and especially during swing (12‐fold), becoming the biggest energy generator across the whole stride at >5 m·s⁻¹. Knee flexor and extensor negative work also rose superlinearly with speed during swing, with the knee flexors becoming the greatest energy absorber over the whole stride at >7.22 m·s⁻¹. Across speeds, plantar flexor peak moment and positive work accounted for 97% and 96% of the variance in step length, and swing hip extension peak moment and positive work accounted for 98% and 99% of the variance in step frequency. There were pronounced speed, phase (stance/swing), and work (positive/negative) dependent contributions of the different functional muscle groups during running, with extensive implications for conditioning and injury prevention.
... From a mechanical perspective, increased eccentric hamstring force and neuromuscular activity can improve sprint performance. Several studies have demonstrated the important role of the hip extensors (gluteal and hamstring muscles) in running performance (Wiemann & Tidow, 1995;Bartlett et al., 2014;Schache et al., 2014). This is because in sprint mechanics, the hamstring muscles decelerate knee extension in the swing phase and then generate horizontal forces through hip extension in the stance phase Miras Moreno, 2020). ...
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The aim of this study was to investigate the relationship between eccentric hamstring muscle strength and acceleration and vertical jump in professional female soccer players. Twentieth professional female soccer players actively playing soccer participated in the study voluntarily with age (arithmetic mean±standard deviation) 18.31±5,97. The NORDBORD device was used to measure the participants' hamstring eccentric force output, the Smartspeed™ Contact Mat was used for vertical jump performance and the FUSIONSPORTS Smartspeed™ PRO photocell (Fusion Sport, Queensland, Australia) was used for 0-20m sprint performance measurements. When the relationship between eccentric hamstring strength parameters, vertical jump and sprint performance of the participants was analyzed, no significance was found. It is seen that there is a negative relationship between VJ and 0-5m at a moderate level (r=-586, p=.022) and a negative relationship between VJ and 0-20m at a high level (r=-.793, p=-.000). Since the studies examining the relationship between Hamstring Strength and Sprint performance are limited in number, it is not possible to reach a definite conclusion, more comprehensive and more studies are needed. Key words: Hamstring, Eccentric, Sprint, Acceleration, Vertical Jump, Football players.
... However, Wall-Scheffler et al. (2010) suggest that the reduction in variability in gluteus maximus activation during higher speed or incline walking compared to running is more compatible with a model of optimization of a walking gait (at varying intensities) being a primary driver of increased gluteus maximus size in humans. More recent data suggests that the gluteus maximus is recruited for fast and powerful movements in a variety of locomotor contexts from sprinting to climbing (Bartlett et al., 2014). While both human and ape gluteals scale with positive allometry (albeit with CI overlapping 0.67) in the current study, the higher regression intercept in humans (1.05 vs. 0.35) supports a grade shift in gluteal size in our evolutionary history, even if the rate of increase relative to body mass within species is relatively similar across all apes. ...
Article
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Introduction: Muscle cross-sectional area is an important variable for understanding force generating potential and locomotor adaptation. Geometric scaling predicts area scales proportionally to body mass2/3. Previous research has quantified scaling relationships between hindlimb musculature and mass in apes, but these relationships have not been clearly established in humans. Scaling in the human lower-limb is likely influenced by bipedalism and dimorphism in lean and total body mass between the sexes. Methods: To investigate these relationships, cross-sectional area in 20 muscles of the lower-limb were obtained through MRI in twenty-eight (14 female, 14 male) participants and measured in Analyze 14.0. Log transformed muscle cross-sectional areas were grouped by function (gluteals, knee extensors, hamstrings, biarticulate knee/hip flexors, plantarflexors), and least-squares regressions were calculated for each group against log-body mass. Results: All muscle groups were significantly (p < 0.001) correlated with mass (0.56 < r² < 0.70) and, except for the gluteals, all groups scaled with positive allometry with slopes outside the 95% CI reported in the literature for apes. Correlations and slopes were lower for females (0.05 < r² < 0.62; 0.4 < b < 1.0), than males (0.56 < r² < 0.79: 0. 7< b < 1.9) in all muscle groups, but there were no statistically significant differences in slope except for the tensor fasciae latae and the hamstrings. However, including sex as a predictor in multiple regression analysis increased the explained variance in cross-sectional area by 1-18% across functional muscle groups. Discussion: These results suggest human lower-limb muscle scaling has responded to force production requirements of bipedalism, but differences in lean and total mass do not clearly impact allometric equations in males and females.
... To conduct this study, a four site surface electromyography (sEMG) was utilized to record electrical muscular activity of the UGMax, LGMax, GMed, and BF. Following the protocol of previous research (2,16,20,23,26), the sensor location and positioning of the sEMG were directly over the 'belly' of the muscle. The electrical muscular activity was measured during a 5-RM performance for all four exercise conditions: BHT, BBHT, BGB, and BBGB. ...
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The importance of hip extensor and abductor muscles for sprint-running speed in sport performance and injury reduction during forceful landing is well-documented. To target these muscle groups, the barbell hip thrust and barbell glute bridge are used to load the posterior kinetic chain while band-resisted abduction exercises, like band-resisted side stepping, target the lateral kinetic chain. However, combining band-resisted hip abduction with barbell hip-extension dominant exercises has not yet been investigated. In this study, twelve male subjects (age = 20.3 ± 1.1 years; height = 184.6 ± 6.9 cm; body mass = 86.8 ± 16.7 kg) with 6.0 ± 2.2 years of resistance training experience underwent a two-part research protocol with surface electromyography (sEMG) measured during a 5-repetition maximum (5-RM) load performance to determine differences in peak and mean muscular activity between barbell hip thrust (BHT) and band-resisted barbell hip thrust (BBHT), and between barbell glute bridge (BGB) and band-resisted barbell glute bridge (BBGB). Repeated measures ANOVAs were conducted to examine mean differences of sEMG activity between BHT and BBHT, BGB and BBGB. The results indicated four significant differences between the pairs. Both band-resisted conditions elicited greater mean sEMG activity in the upper gluteus maximus compared to non-banded conditions, and BBHT elicited greater peak sEMG activity in the upper gluteus maximus compared to non-banded conditions. However, BGB unexpectedly elicited greater sEMG activity in the gluteus medius compared to BBGB. The differences in muscle activity could potentially be explained by reciprocal inhibition and synergistic dominance. Further research is needed to make definitive statements on the superiority of band-resisted barbell exercises over non-banded barbell exercises and transferability to sport performance.
... The authors stated that it would be a correct approach to add specific exercises that develop the posterior abdominal wall muscles to the general weightlifting programs at the point of contributing to the athletic success of Olympic weightlifters in national and international competitions 20 . Gluteal muscles have important functions in keeping the trunk upright, stabilizing the hip joint, climbing stairs, fixing the hip and knee joints in weight lifting, sprinting, squatting and climbing a steep hill [21][22][23] . In a study in which the muscle cross-sectional surface areas of the gluteal muscles of Olympic style weightlifting athletes were determined through magnetic resonance images, it has been explained that the gluteus maximus muscle cross-sectional surface area of the athletes is larger than the gluteus maximus muscle cross-sectional areas of the sedentary individuals, but no statistical difference was observed between the gluteus medius and minimus muscle group crosssectional areas of the athletes and sedentary groups. ...
Article
Objective: It was aimed to investigate hip flexion and extension muscle strength of female weightlifters athletes participating in national and international weightlifting championships. Methods: Hip extension, hip flexion strength measurements, weightlifting performances and demographic data of female athletes participating in international weightlifting championships (n= 15) and female athletes participating in national weightlifting championships (n= 15) included in our study were determined. Hip flexion/extension muscle strength measurements of the athletes were performed with a Lafayette hand-held dynamometer. Results: It was observed that hip flexion and extension muscle strength values of female weightlifters who do weightlifting at international level values were higher than the values of female weightlifters who do weightlifting at the national level (p < .05). There was a statistically significant difference between right-left hip-flexion values in female weightlifting athletes who do elite weightlifting sports (p < .05). Conclusion: It was determined that hip extension-flexion muscle strength of athletes participating in international championships were higher than hip extension-flexion muscle strength values of athletes participating in national championships. Considering that asymmetrical developments may cause sports injuries, it is thought that it is important to evaluate the asymmetrical development of hip muscle groups in certain periods.
... In contrast, walking downhill, which is analogous to our forward pull manipulation, substantially increases the hip flexor moment, and the negative work and power produced by hip flexor muscles ( Kuster et al., 1995 ;Park et al., 2019 ). Consistent with these observed changes in hip joint moments, several studies have documented in-creased activity in muscles that produce extensor moments at the hip joint when subjects walk and run uphill ( Wall-Scheffler et al., 2010 ;Franz & Kram, 2012 ;Vernillo et al., 2017 ) and accelerate during sprinting ( Bartlett et al., 2014 ). Finally, two hip extensor muscles, gluteus maximus and biceps femoris, have been shown to increase activity when subjects walked and ran with an added rearward directed force and activity decreased when the subjects walked and ran with an added forward directed force . ...
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During locomotion, cervical muscles must be active to stabilize the head as the body accelerates and decelerates. We hypothesized that cervical muscles are also part of the linked chain of axial muscles that provide core stabilization against torques applied to the hip joint by the extrinsic muscles of the legs. To test whether specific cervical muscles play a role in postural stabilization of the head and/or core stabilization of the pelvic girdle, we used surface electromyography to measure changes in muscle activity in response to force manipulations during constant speed running and maximum effort counter-movement jumps. We found that doubling the mass of the head during both running and maximum effort jumping had little or no effect on (1) acceleration of the body and (2) cervical muscle activity. Application of horizontal forward and rearward directed forces at the pelvis during running tripled mean fore and aft accelerations, thereby increasing both the pitching moments on the head and flexion and extension torques applied to the hip. These manipulations primarily resulted in increases in cervical muscle activity that is appropriate for core stabilization of the pelvis. Additionally, when subjects jumped maximally with an applied downward directed force that reduced acceleration and therefore need for cervical muscles to stabilize the head, cervical muscle activity did not decrease. These results suggest that during locomotion, rather than acting to stabilize the head against the effects of inertia, the superficial muscles of the neck monitored in this study help to stabilize the pelvis against torques imposed by the extrinsic muscles of the legs at the hip joint. We suggest that a division of labor may exist between deep cervical muscles that presumably provide postural stabilization of the head versus superficial cervical muscles that provide core stabilization against torques applied to the pelvic and pectoral girdles by the extrinsic appendicular muscles.
... Recent studies on EMG performed during sprinting found that the gluteus maximus was strongly activated during sprinting. 1,6,[28][29][30] According to these studies, the muscle activity of the gluteus maximus was directly proportional to the running velocity, especially when swinging the leg posteriorly from the latter half of the swing phase to the first half of the support phase. This was called the braking phase. ...
Article
Purpose: This study aimed to investigate the level of muscle activity during sprint running using T2-weighted magnetic resonance imaging. Methods: Fourteen male sprinters (age 21.2 [4.0] y; height 171.8 [4.2] cm, weight 65.5 [5.3] kg, 100-m personal record 11.01 [0.41] s; mean [SD]) performed 3 sets of three 60-m round-trip sprints. Before and after the round-trip sprints, 3 T magnetic resonance imaging scans were performed to obtain the T2 values of the 14 athletes' lower-extremity muscles. Results: After the 60-m round-trip sprints, the T2 value of the gluteus maximus, long head of biceps femoris, semitendinosus, semimembranosus, adductor brevis, adductor longus, adductor magnus, and gracilis increased significantly. The rate of change in the T2 values before and after the 60-m round-trip sprints was notably higher in the semitendinosus and gluteus maximus than in the other muscles. Conclusions: These findings demonstrate the specific physiological metabolism of the lower-extremity muscles during fast sprinting. There are particularly high levels of muscle activity in the gluteus maximus and semitendinosus during sprint performance.
... Healthy hip abductor muscles are a good indicator of a healthy hip and an active lifestyle as they are fundamental to human daily activities, such as standing, walking and running 1,2 . Fatty infiltration and muscle wasting (atrophy) are associated with loss of strength and mobility, making volume and intramuscular fat (IMF) content important markers for muscle health [3][4][5][6][7][8][9][10][11][12][13] . ...
Article
Healthy hip abductor muscles are a good indicator of a healthy hip and an active lifestyle, as they are greatly involved in human daily activities. Fatty infiltration and muscle atrophy are associated with loss of strength, loss of mobility and hip disease. However, these variables have not been widely studied in this muscle group. We aimed to characterize the hip abductor muscles in a group of healthy individuals to establish reference values for volume, intramuscular fat content and shape of this muscle group. To achieve this, we executed a cross-sectional study using Dixon MRI scans of 51 healthy subjects. We used an automated segmentation method to label GMAX, GMED, GMIN and TFL muscles, measured normalized volume (NV) using lean body mass, fat fraction (FF) and lean muscle volume for each subject and computed non-parametric statistics for each variable grouped by sex and age. We measured these variables for each axial slice and created cross-sectional area and FF axial profiles for each muscle. Finally, we generated sex-specific atlases with FF statistical images. We measured median (IQR) NV values of 12.6 (10.8-13.8), 6.3 (5.6-6.7), 1.6 (1.4-1.7) and 0.8 (0.6-1.0) cm3 /kg for GMAX, GMED, GMIN and TFL, and median (IQR) FF values of 12.3 (10.1-15.9)%, 9.8 (8.6-11.2)%, 10.0 (9.0-12.0)% and 10.2 (7.8-13.5)% respectively. FF values were significantly higher for females for the four muscles (p < 0.01), but there were no significant differences between the two age groups. When comparing individual muscles, we observed a significantly higher FF in GMAX than in the other muscles. The reported novel reference values and axial profiles for volume and FF of the hip abductors, together with male and female atlases, are tools that could potentially help to quantify and detect early the deteriorating effects of hip disease or sarcopenia.
... Overall, it has been shown that the hip extensor and flexor muscles (i.e., gluteals and hamstrings) play a pivotal role in performance across all sprint phases (12,175) and display increasingly greater activation as running speeds increase to maximal sprinting (174). This is further supported by findings that have shown that athletes with a better ability to orientate horizontal GRFs can highly activate their hamstrings just before ground contact and present high hip extensor torque capabilities (137). ...
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This review provides a definition for multidirectional speed (MDS) and evaluates its technical and mechanical underpinnings. This review explores each component of MDS while considering unique aspects of youth physiology and epidemiology. With a theoretical understanding of MDS, practitioners will be more informed on the planning and periodization of MDS training methods in soccer. MDS comprises linear speed, change of direction speed, curvilinear speed, contextual speed, and agility, which each have distinct physiological, biomechanical, and neurocognitive distinctions that can either be differentiated or harmonized to optimize training.
... The rectified sEMG signals were subsequently passed through a fourth-order Butterworth low-pass filter at 10 Hz. The processed sEMG signals for all environments were normalized against each individual's peak muscle activation amplitude during the flat-ground trial [36,37]. The individual peak muscle activation amplitude was defined as the maximum amplitude in the stance phase while walking on flat-ground. ...
Article
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Classification of terrain is a vital component in giving suitable control to a walking assistive device for the various walking conditions. Although surface electromyography (sEMG) signals have been combined with inputs from other sensors to detect walking intention, no study has yet classified walking environments using sEMG only. Therefore, the purpose of this study is to classify the current walking environment based on the entire sEMG profile gathered from selected muscles in the lower extremities. The muscle activations of selected muscles in the lower extremities were measured in 27 participants while they walked over flat-ground, upstairs, downstairs, uphill, and downhill. An artificial neural network (ANN) was employed to classify these walking environments using the entire sEMG profile recorded for all muscles during the stance phase. The result shows that the ANN was able to classify the current walking environment with high accuracy of 96.3% when using activation from all muscles. When muscle activation from flexor/extensor groups in the knee, ankle, and metatarsophalangeal joints were used individually to classify the environment, the triceps surae muscle activation showed the highest classification accuracy of 88.9%. In conclusion, a current walking environment was classified with high accuracy using an ANN based on only sEMG signals.
... The activity level of the distal region seems to be higher during hip extension than during hip external rotation (Contreras, Vigotsky, Schoenfeld, Beardsley, & Cronin, 2015). Additionally, it was speculated that the distal region of Gmax contributes to the generation of the hip extension torque to resist hip flexion at foot strike during running (Bartlett, Sumner, Ellis, & Kram, 2014). These findings suggest that the distal region of Gmax predominantly acts for hip extension. ...
Article
Purpose: Muscle hypertrophy can occur non-uniformly in athletes who repetitively perform particular movements, presumably leading to a unique muscle size distribution along the length. The present study aimed to examine if sprinters have unique size distributions within the gluteus and posterior thigh muscles. Methods: Nineteen male sprinters and 20 untrained males participated in the present study. T1-weighted magnetic resonance images of the hips and right thigh were obtained in order to determine whole and regional (proximal, middle, and distal) volumes of the gluteus maximus and individual posterior thigh muscles. Results: The results showed that the volumes of all the examined muscles relative to body mass were significantly larger in sprinters than in untrained males (all P < 0.001, d = 1.40-3.29). Moreover, the magnitude of the difference in relative volume between sprinters and untrained males was different between the regions within the gluteus maximus (P = 0.048, partial η2 = 0.187), semitendinosus (P = 0.004, partial η2 = 0.331), and adductor magnus (P = 0.007, partial η2 = 0.322), but not within the other posterior thigh muscles (P = 0.091-0.555, partial η2 = 0.025-0.176). The magnitude of the difference in relative volume between the sprinters and untrained males was greatest in the distal regions within the gluteus maximus and semitendinosus, while the proximal region within the adductor magnus. Conclusion: These findings indicate that sprinters have unique size distributions within the gluteus maximus, semitendinosus, and adductor magnus, which may be attributed to their competitive and training activities.
... There is not much information on the activation time of the RF during walking but the relationship between speed and activation has been compared. Barlett et al. [18] examined the GM in two parts, upper and lower. They found that the the upper part start contraction at the beginning of the stance phase and at the end of the swing phase. ...
... There is not much information on the activation time of the RF during walking but the relationship between speed and activation has been compared. Barlett et al. [18] examined the GM in two parts, upper and lower. They found that the the upper part start contraction at the beginning of the stance phase and at the end of the swing phase. ...
Article
Objectives: The rectus femoris muscle flexes the thigh, while the gluteus maximus muscle extends it. Understanding the activations of these two muscles that function in opposition to each other during walking facilitates the interpretation of gait pathologies. The aim of this study was to evaluate the activations of these muscles during walking by using the surface electromyography (EMG) technique. Methods: Twenty female volunteers aged 18–26 years participated in our study. The electrical activation of the rectus femoris and gluteus maximus muscles of the participants was simultaneously evaluated by gait analysis. At the same time, spatiotemporal parameters and phase parameters were obtained. Results: The activation pattern of both muscles was found to be similar. Both muscles reached the highest activation in the swing phase. The lowest activation was also seen in the pre-swing phase. Both muscles were observed to be active in the loading and single-limb support phases. Conclusion: The fact that these two antagonists muscles are active at the same time suggests that one is functioning concentrically, while the other eccentrically. Thus, stabilization of hip joint is provided when the body moves forward.
... The activity of hip extensors changes depending on the acceleration phase. At the initial acceleration (first 10 steps), the EMG activity of the gluteus contributes to the generation of a horizontal force that is greater than the BF activity 32,35 . ...
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Objective: the purpose of this study was to identify differences in hamstring passive stiffness between the pre-season and in-season periods. Methods: Hamstring strength and passive stiffness were measured in professional male soccer players before and after the pre-season (4 weeks), and after the in-season (6 weeks) periods using an isokinetic dynamometer. Muscle passive stiffness was determined from the slope of the passive torque-angle relationship. External loads (acceleration and jumps) were monitored by GPS and internal loads by questionnaire. Results: Hamstring passive stiffness increased after 10 weeks of training and matches, without changes in passive peak torque and range of motion. The hamstring passive stiffness modifications were associated with the volume and intensity of accelerations and jumps. The individual data analysis also provided some support for the suppression of the biomechanical adaptation in the subjects with relatively large external load. Conclusions: Regular training and match workouts increase hamstring passive stiffness in professional soccer players but the adaptation of muscle-tendon unit passive elements might not occur if players experience excessive mechanical stress.
... The gluteal muscles play an important role in daily living activities, including walking, running, stair climbing and lifting activities [1,2]. Gluteus maximus is the largest of the gluteal muscles and has many different functions such as providing sacroiliac joint stability, strength for lifting and, in the running gait cycle, flexes the trunk on the stance-side and decelerate the swing leg [3,4]. ...
Article
Objective To design, develop and evaluate an automated multi-atlas method for segmentation and volume quantification of gluteus maximus from Dixon and T1-weighted images.Materials and methodsThe multi-atlas segmentation method uses an atlas library constructed from 15 Dixon MRI scans of healthy subjects. A non-rigid registration between each atlas and the target, followed by majority voting label fusion, is used in the segmentation. We propose a region of interest (ROI) to standardize the measurement of muscle bulk. The method was evaluated using the dice similarity coefficient (DSC) and the relative volume difference (RVD) as metrics, for Dixon and T1-weighted target images.ResultsThe mean(± SD) DSC was 0.94 ± 0.01 for Dixon images, while 0.93 ± 0.02 for T1-weighted. The RVD between the automated and manual segmentation had a mean(± SD) value of 1.5 ± 4.3% for Dixon and 1.5 ± 4.8% for T1-weighted images. In the muscle bulk ROI, the DSC was 0.95 ± 0.01 and the RVD was 0.6 ± 3.8%.Conclusion The method allows an accurate fully automated segmentation of gluteus maximus for Dixon and T1-weighted images and provides a relatively accurate volume measurement in shorter times (~ 20 min) than the current gold-standard manual segmentations (2 h). Visual inspection of the segmentation would be required when higher accuracy is needed.
... Far from merely contradicting the use of surface electromyography, the PG can be used alongside it to determine the evolution of the genus Homo. Gluteus maximus activity, for instance, is higher in endurance running than it is in walking (Lieberman et al., 2006), and the muscle is even more active in sprinting than it is in endurance running (Bartlett et al., 2013). A large gluteus maximus that developed to facilitate sprinting is therefore an example of a SBMA, which could explain the significantly smaller PG in short-distance events versus long-distance events and the higher levels of gluteus maximus engagement during sprinting versus endurance running or walking. ...
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Men outperform women in sports that require muscular strength and endurance, but the magnitude of this performance gap (PG) does not appear to be constant; that is, the PG between men and women is greater in some sports than it is in others. Here, we examine the size of this gap within the realm of track and field by comparing the top 50 world-record performances of men to the top 50 records set by women in a number of long-distance running, medium-distance running, short-distance running, and jumping events. While women do not perform at the level of men in any track and field event, the magnitude of the PG trends up or down depending on the type of event. Jumping events exhibit a larger gap between the sexes than do running events, and short-distance running events show a smaller disparity between the sexes than do medium- or long-distance running events. This difference suggests that general sexual dimorphism does not explain why female performance is relatively closer to male performance at some track and field events than others. We hypothesize that this trend can be explained by the presence of sex-blind musculoskeletal adaptations (SBMA’s), which accumulate over generations to reduce the size of the PG in certain movements. We conclude that the selection trend favoring in humans should be explored further to determine whether the PG in sport can indeed be used to determine movements to which the human body is adapted.
... Although numerous kinetic analyses of locomotion on Earth have identified low activity in the GM during steady speed, level walking, it is known that this muscle also contributes greatly to spinal stabilization. [16,17] As postural muscles, the spinal stabilizers would likely atrophy during a return mission to Mars, therefore, any deficits in GM motor recruitment while walking on Mars could have significant implications. ...
Article
Context: With a long duration return mission to Mars on the horizon, we must learn as much about the environment and its influence on the musculoskeletal system as possible to develop countermeasures and mitigate deleterious health effects and maladaptation. Aims: To determine the influence of simulated Mars gravity on the activity of four locomotor muscles while walking, in comparison to 1 G, using lower body positive pressure (LBPP). Material and methods: A total of 14 male subjects (mean age: 20.6 ± 2.4 years) performed bouts of walking in both simulated Mars gravity (0.38 G) and Earth gravity (1 G) using an LBPP device. The dependent variables were the muscle activity evoked in the tibialis anterior, vastus lateralis, gluteus maximus and lateral portion of the gastrocnemius, measured using electromyography and expressed as percentages of maximum voluntary isometric contractions, and heart rate (HR). For statistical analysis, a paired t-test was performed. Statistical significance was defined as P < 0.05. Results: No significant differences in muscle activity were found across conditions for any of the investigated muscles. A significant mean difference in the HR was identified between Earth (105.15 ± 8.1 bpm) and Mars (98.15 ± 10.44 bpm) conditions (P = 0.027), wherein the HR was lower during the Mars trial. Conclusions: The Mars environment may not result in any deteriorative implications for the musculoskeletal system. However, if future research should report that stride frequency and thus activation frequency is decreased in the simulated Mars gravity, negative implications may be posed for muscle retention and reconditioning efforts on the Red Planet.
... Several studies have consistently shown the crucial role of hamstring muscles in running performance (e.g. Bartlett, Sumner, Ellis, & Kram, 2014;Schache, Dorn, Williams, Brown, & Pandy, 2014), specifically in those sports such as athletics, rugby and soccer where sprint running is paramount ( Morin et al., 2015) and where maximal acceleration is key for performing defensive and offensive actions (Faude, Koch, & Meyer, 2012). The horizontal component of the resultant ground reaction force (GRF) has been shown to be the key factor to achieve significant levels of acceleration and sprint performance. ...
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Hamstring injuries are the most common and recurrent muscular injuries in soccer. Studies have confirmed that hamstring strains account for 11% to 16% of the total injuries in soccer and require long recovery periods. The purpose of this systematic review was to determine the most effective exercise intervention for the prevention of hamstring injuries in professiona and semi-professional soccer players. A literature search was performed in June and July 2018 to identify eligible studies in PubMed and SportDiscuss databases. Boolean operators were used to combine the following terms: hamstring*, muscle*, injur*, prevent*, soccer. The initial search resulted in 315 articles which were filtered to 6 articles based on inclusion and exclusion criteria. Results showed that eccentric training significantly reduced the incidence (RR=0.35; p<0.01) and number (p<0.05) of hamstring injuries. Injury rate was lower after an eccentric program for both new (RR=0.410; p=0.34) and recurrent injuries (RR=0.137; p=0.003). Players showed greater EMG activity and eccentric peak torque (p=0.01) and an increase in optimum length in knee flexors after a period of eccentric training (p<0.05). Stretching during the warm-up reduced the severity of hamstring injury (p=0.006), while flexibility training showed no effects in incidence of hamstring strains (p=0.91). This systematic review suggested the effectiveness of NHE and other eccentric exercises such as eccentric drops, lunge pushes and deceleration steps, to prevent hamstring injuries among professional and semi- professional soccer players. It was also shown that providing periodic isokinetic testing after correcting imbalances is crucial for attenuating the risk of hamstring injury. Key words: hamstring, injury, injury prevention, soccer
... Many studies during the last few decades have focused on general upper-limb strength in sport climbers [10][11][12]. Limited research has been conducted on lower extremity muscles work during sport climbing [13,14]. Sport climbing requires more upper than lower limb strength, but with good technique, most of the power should come from the lower body, with the upper body providing the ability to balance and stay close to the wall [15][16][17]. ...
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Introduction. Productive sporting performance in various sports disciplines often heavily depends on jumping abilities as well as on lower limb muscles power and endurance of the athletes involved. Both CrossFit, a popular high-intensity training program and sport climbing require lower extremity muscular power and endurance. Aim. The aim of this study was to compare vertical jumping abilities, endurance and quickness of the regeneration in gastrocnemius lateralis (GL), vastus medialis (VMO) and gluteus maximus (GM) muscles in CrossFit athletes and sport climbers. Material and methods. The study comprised 20 male athletes aged 24.3±4.7, divided into two equal groups: training CrossFit (CF) and sport climbers (SC). Vertical jump test was recorded by Vicon® motion capture system and AMTI® biomechanics force platforms. The myoelectric activity of the GL, VMO and GM muscles was recorded by myon®. Results. Significant difference in height of vertical jump in CrossFit athletes and sport climbers was observed (SC: 125.43 cm, 120.92 cm; CF: 110.42 cm, 110.86 cm; p<0.05). The endurance of the GL muscles in athletes using CrossFit training is significantly higher in comparison to sport climbers. Athletes training CrossFit have a better ability to recover GL, GM and VMO muscles than sport climbers. Conclusions. Sport climbers have better results in vertical jump tests than the athletes doing CrossFit. The endurance of the GL muscles in athletes doing CrossFit is higher in comparison to sport climbers. Athletes doing CrossFit have also better ability to muscles recover than sport climbers.
... The use of the equine GM during increasing speed and treadmill gradient was documented [3][4][5][6], and both increases in speed and treadmill inclination were found to increase EMG activity due to the higher workload of the GM. In the human gluteus maximus, Bartlett et al. [7] also found that increased muscle activity is related to the speed and intensity of the movement, somewhat independent of the gait (walk or run). Recently, integrated EMG values for GM in Thoroughbred racehorses were documented to increase uphill, but not decrease downhill compared to flat work on the treadmill [6]. ...
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Abstract Background The equine m. gluteus medius (GM) is the largest muscle of the horse, its main movement function is the extension of the hip joint. The objective of the present study was to measure equine GM activity in three adjacent locations on GM during walk and trot on a treadmill, in order to document potential differences. Fourteen Haflinger mares were measured using surface electromyography and kinematic markers to identify the motion cycles on three occasions over 16 weeks. The electrodes were placed on left and right gluteus medius muscle over the middle of its widest part and 5 cm lateral and medial of it. For data processing, electrical activity was normalised to its maximum value and timing was normalised to the motion cycle. A Gaussian distribution approach was used to determine up to 10 modes of focussed activity, and results were analysed separately for stance and swing phase of the ipsilateral hindlimb. Results Fair reliability was found for mean mode values (Cronbach’s alpha = 0.66) and good reliability was found for mean mode locations (Cronbach’s alpha = 0.71) over the three data collection days. The magnitude of muscle activity identified as mean mode value was much larger at trot than at walk, and mean mode value was significantly different between stance phases of walk and trot for all electrode positions (p
... 9,11,51,52 A holistic approach that includes the entire kinetic chain ensures that further unloading of the tendon may occur, as other structures, such as the gluteal muscles, may contribute more to running. 62,63 This highlights the importance of continued load management in the long term, particularly since a decrease in pain is not necessarily reflective of tendon healing 5,53,64 and therefore load management and improvement in load tolerance must continue throughout the patient's athletic career. ...
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Background and purpose: While there is much discussion about tendinopathy in the literature, there is little reference to the less common condition of iliopsoas tendinopathy, and no documentation of the condition in runners. The iliopsoas is a major decelerator of the hip and eccentric loading of the iliopsoas is an important component of energy transfer during running. Eccentric training is a thoroughly researched method of treating tendinopathy but has shown mixed results. The purpose of this case report is to describe the rehabilitation of a runner with iliopsoas tendinopathy, and demonstrate in a creative eccentric-biased technique to assist with treatment. A secondary objective is to illustrate how evidence on intervention for other tendinopathies was used to guide rehabilitation of this seldom described condition. Case description: The subject was a 39-year-old female middle distance runner diagnosed with iliopsoas tendinopathy via ultrasound, after sudden onset of left anterior groin pain. Symptoms began after a significant increase in running load, and persisted, despite rest, for three months. The intervention consisted of an eccentric-biased hip flexor exercise, with supportive kinetic chain exercises and progressive loading in a return to running program. Outcomes: The Copenhagen Hip and Groin Outcome Score, the Visual Analogue Scale, the Global Rating of Change Scale and manual muscle testing scores all improved after 12 weeks of intervention with further improvement at the five-year follow up. After 12 weeks of intervention, the subject was running without restriction and had returned to her pre-injury running mileage at the five-year follow up. Discussion: The eccentric-biased exercise in conjunction with exercises addressing the kinetic chain and a progressive tendon loading program, were successful in the rehabilitation of this subject with iliopsoas tendinopathy. This case report is the first to provide a description on the rehabilitation of iliopsoas tendinopathy, and offers clinicians suggestions and guidance for treatment and exercise choice in the clinical environment. Level of evidence: 5.
... From our experience, we estimate that patients with proximal and distal ischemia, that is to say buttocks associated with calf ischemia, preferentially complain of calf pain on a flat surface and buttock pain when climbing uphill, maybe because of different modifications of their respective oxygen demand in different walking situations. [32][33][34] ...
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Data on simultaneous hemodynamic changes and pain rating estimation in arterial claudication while walking are lacking. This study was conducted to determine if a difference in transcutaneous oxygen pressure (tcpO2) exists between proximal and distal localization at pain appearance (PAINapp), maximal pain (PAINmax) and pain relief (PAINrel) in proximal or distal claudication and if a relationship exists between tcpO2 changes and pain intensity. We analyzed the pain rating (Visual Analog Scale (VAS)) to lower limb ischemia, measured with the decrease from rest of oxygen pressure (DROP) tcpO2 index during constant-load treadmill tests in patients with calf (n = 41) or buttock (n = 19) claudication. Calves versus buttocks results were analyzed with ANOVA tests. The R² correlation coefficient between individual VAS versus DROP was calculated. Ischemia intensity versus pain rating changes were correlated. Significant ischemia was required for pain appearance, but pain disappeared despite the persistence of ischemia. We observed no statistical difference for DROP at PAINapp, PAINmax or PAINrel between proximal or distal claudication. A significant correlation between pain rating versus DROP was found: from PAINapp to PAINmax, R² = 0.750 (calves) and 0.829 (buttocks), and from PAINmax to PAINrel, R² = 0.608 (calves) and 0.560 (buttocks); p<0.05. Pain appeared after a significant decrease of hemodynamic parameters but disappeared while parameters were not normalized. No difference in pain rating was found in proximal versus distal claudication.
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A 72-year-old male presented for evaluation of a 2-wk history left buttock pain that began while playing pickleball. He sustained a left inversion ankle sprain while in a squatted position and landed on his left buttock. Four days after his injury, he developed extensive bruising involving his lower back, buttock, and left thigh. On examination, he had tenderness to palpation at the left side of the sacrum and in the region of the deep external rotators. Left hip range of motion was full in extension but limited to 90° of flexion, which reproduced left-sided buttock pain. External rotation provoked pain, but internal rotation was full and pain free. MRI of the pelvis demonstrated a grade 2 partial thickness tear of the left gluteus maximus muscle at its distal myotendinous junction with associated retraction and intramuscular hematoma. He was managed with compression with biking shorts, icing, acetaminophen, and physical therapy. He returned to pickleball approximately 4 wk after his injury, and at his 4-wk follow-up, he reported 99% improvement in his symptoms with the only remaining complaint being minimal discomfort with gluteal stretching.
Article
PurposeTo clarify the influence of additional internal iliac artery (IIA) resection on the loss of the gluteus muscle volume after pelvic exenteration (PE).Methods The subjects of this retrospective analysis were 78 patients who underwent PE with or without IIA resection (n = 44 and n = 34, respectively) between 2006 and 2018. The areas of gluteal muscles (GMs) and psoas muscles (PSMs) were calculated using CT images before and 6 months after PE, and the difference was compared.ResultsThe volumes of the GMs and PSMs were significantly reduced after PE (P < 0.001 and P = 0.005, respectively). In the IIA resection group, the GMs were significantly reduced after surgery, but the PSMs were not. The maximum GM (Gmax) was the most atrophied among the GMs. Multivariable analysis revealed that complete IIA resection was an independent promotor of the loss of volume of the Gmax (P = 0.044). In 18 patients with unilateral IIA resection, the downsizing rate of the Gmax was significantly greater on the resected side than on the non-resected side (P = 0.008).Conclusions The GMs and PSMs were significantly smaller after PE. Complete IIA resection reduced the Gmax area remarkably. Preservation of the superior gluteus artery is likely to help maintain Gmax size, suggesting a potential preventative measure against secondary sarcopenia.
Chapter
Vertical climbing has played a central role in the evolutionary history of the primate foot. Yet, to date, very little experimental work has examined how the primate foot functions during climbing, due in part to logistical limitations and ethical considerations associated with experimental data collection. Additionally, the current literature generally lacks an integrative approach for collecting multiple types of data and examining the interactions of various physical setups in an experimental setting. This chapter reviews literature on the experimental biomechanics of primate climbing, with a focus on the primate hindlimb and foot. We first describe how the primate foot is used during climbing in naturalistic contexts. We then review and synthesize studies on four aspects of the primate foot during climbing: spatiotemporal features, kinematics, kinetics, and electromyography. We conclude that future studies should attempt to include more biomechanical data on the foot specifically, collect data that allow an understanding of how substrate affects foot function, and broaden the species sample from which data are collected.
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The two types of skeletal muscle fibers are the slow-twitch (type I) and the fast-twitch (type II) fibers. Slow-twitch muscles are activated in long resistance exercise, while fast-twitch muscles are activated in forceful breakouts. Sprinters have larger type II than type I fiber areas in their leg extensor muscles because their training mainly includes fast repetitive movements. Muscle size is strongly related to better performance in the literature, with sprinters appearing to have more developed lower limb muscles. Essential elements of a high sprint performance are the ability to accelerate rapidly, the size of maximal velocity, and the ability to maintain this velocity. At the muscle level, force, velocity, and power are mainly influenced by fiber type distribution and architecture. Moreover, a strong positive correlation between fascicle length and mechanical power production applies. An increase in muscle thickness leads to a greater force production capacity of the muscle with a subsequently improved acceleration ability. It is general belief that males are faster than females because males have more muscle mass. Differences between male and female sprinters include differences in musculotendinous stiffness and greater structural compliance in females, while muscle fiber type composition and muscle fascicle length are similar. Measurement of muscle thickness is achieved with MRI and ultrasonography. In a biomechanics aspect, as a sprint begins, the generation of forward acceleration is probably the most essential factor that determines the performance. The most important muscle group, which plays a predominant role as running speed increases and reaches maximal sprint speeds, is the hip extensor/knee flexor muscles and the quality of the foot muscles.
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Introduction: The inability to maintain good pelvic stability has been attributed to inefficient muscle coordination and deconditioning of the stabilizing muscles. Despite this, little is known about the role of the pelvic muscles in anteversion and retroversion movements. Objective: To compare the neuromuscular activity of the tensor fascia lata, gluteus medius, upper and lower portions of the gluteus maximus, and multifidus in pelvic anteversion and retroversion. Methods: The neuromuscular activity of 17 healthy young adults (aged 25.3 ± 4.6 years) was assessed during five repetitions of the pelvic anteversion and retroversion movements. The Vicon-Nexus system (10 cameras) was used for the kinematic analysis of the pelvis in the sagittal plane (anteversion and retroversion), and the TeleMyo DTS Desk Receiver electromyograph and the Myomuscle v. 3.8 software to measure neuromuscular activity. The paired samples t-test was used to compare muscle activity between pelvic anteversion and retroversion movements using the Statistica v.8 software with a significance level of p < 0.05. Results: The comparison of the movements showed greater muscle activity in the inferior gluteus maximus in retroversion and greater activity in the multifidus in pelvic anteversion. The upper portion of the gluteus maximus showed relevant activation in both movements. Conclusion: There was more pronounced activity of the lower portion of the gluteus maximus in retroversion, while the upper gluteus maximus showed relevant activation level in both movements. The multifidi were more active in retroversion.
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The human body is exceptional for many reasons, not the least of which is the wide variety of movements it is capable of executing. Because our species is able to execute so many discrete activities, researchers often disagree on which were the movements most essential to the evolution of our species. This paper continues a recently introduced analysis, that the performance gap between female and male athletes narrows in sports which most reflect the movements humans evolved to do. Here, I examine the performance gap in rock climbing. Female climbers are some of the best in the world irrespective of gender, a trend that is not found in any other major sport. I conclude that the exceptional ability of female rock climbers relative to male rock climbers is further evidence of the existence of sex-blind musculoskeletal adaptations, which developed over the course of human evolution – as a result of external (non-sexual) selection forces – to facilitate essential movements. These adaptations abate some of the general physical sexual dimorphism which exists in humans. This paper provides more evidence that the human body was shaped, in part, by pressure to climb well.
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Objective To investigate the effect of unilateral internal iliac artery (IIA) embolization for endovascular aortic repair (EVAR) on gluteal muscle size. Methods We assessed the gluteal muscle size in 111 consecutive patients who underwent elective EVAR with unilateral IIA embolization (n=31) or without IIA embolization (n=80) for abdominal aortic and/or iliac artery aneurysm. The cross-sectional area (CSA) of the gluteus maximus (Gmax) and gluteus medius/minimus (Gmed/min) was measured on computed tomography preoperatively, 6 months postoperatively, and final follow-up. Mean changes in the Gmax and Gmed/min CSA were evaluated using a mixed model analysis of variance. Results In the patients with embolization, both the Gmax and Gmed/min CSA significantly decreased over time on the embolization and non-embolization sides (p < 0.001); however, embolization did not affect the changes in the Gmax CSA (p = 0.64) and Gmed/min CSA (p = 0.99). In the patients with embolization and those without embolization, both the Gmax and Gmed/min CSA significantly decreased over time (p < 0.001); however, embolization did not affect the changes in the Gmax CSA (p=0.76) and Gmed/min CSA (p = 0.11). Conclusions Unilateral IIA embolization was not associated with gluteal muscle atrophy after EVAR. Preemptive unilateral IIA embolization for EVAR seems to be an acceptable procedure in terms of maintenance of gluteal muscle size.
Chapter
Large felid predators have posed significant threats to various primate lineages since Miocene times. In the case of leopards (Panthera pardus), natural selection has fostered the ability to recognize these cats in a number of nonhuman primates. This perceptual ability is maintained in habitats where these predators are no longer present. In a similar domain, the hominin fossil record provides evidence of a long period of exposure to felid predators. Thus, it is reasonable to hypothesize that natural selection engendered some evolved felid-recognition abilities in human ancestors. As explorations of this potential, experimental studies show that children and adults are capable detectors of lion images embedded in arrays of nondangerous antelope. In this chapter, the perceptual aspects of lions are investigated further by reviewing the neurobiological underpinnings of face recognition and shape and texture-processing which include the contextual associations that promote object recognition. Cave lions (Panthera spelaea) were an important component of cave drawings and mobiliary sculptures of Aurignacian hunter–gatherers in the early Upper Paleolithic of Europe. Some features of cave lions, such as facial markings and body contours are portrayed in drawings and figurines with anatomical realism, suggesting a level of visual salience that might be indicative of an evolutionary influence.
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Purpose Intramuscular fat infiltration is a dynamic process, in response to exercise and muscle health, which can be quantified by estimating fat fraction (FF) from Dixon MRI. Healthy hip abductor muscles are a good indicator of a healthy hip and an active lifestyle as they have a fundamental role in walking. The automated measurement of the abductors' FF requires the challenging task of segmenting them. We aimed to design, develop and evaluate a multi-atlas based method for automated measurement of fat fraction in the main hip abductor muscles: gluteus maximus (GMAX), gluteus medius (GMED), gluteus minimus (GMIN) and tensor fasciae latae (TFL). Method We collected and manually segmented Dixon MR images of 10 healthy individuals and 7 patients who underwent MRI for hip problems. Twelve of them were selected to build an atlas library used to implement the automated multi-atlas segmentation method. We compared the FF in the hip abductor muscles for the automated and manual segmentations for both healthy and patients groups. Measures of average and spread were reported for FF for both methods. We used the root mean square error (RMSE) to quantify the method accuracy. A linear regression model was used to explain the relationship between FF for automated and manual segmentations. Results The automated median (IQR) FF was 20.0(16.0–26.4) %, 14.3(10.9–16.5) %, 15.5(13.9–18.6) % and 16.2(13.5–25.6) % for GMAX, GMED, GMIN and TFL respectively, with a FF RMSE of 1.6%, 0.8%, 2.1%, 2.7%. A strong linear correlation (R² = 0.93, p < .001, m = 0.99) was found between the FF from automated and manual segmentations. The mean FF was higher in patients than in healthy subjects. Conclusion The automated measurement of FF of hip abductor muscles from Dixon MRI had good agreement with FF measurements from manually segmented images. The method was accurate for both healthy and patients groups.
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Full-text available at: https://www.ncbi.nlm.nih.gov/books/NBK532884/
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Monaghan, DJ and Cochrane, DJ. Can backward sled towing potentiate sprint performance? J Strength Cond Res XX(X): 000-000, 2019-The objectives of this study were to determine whether backward sled towing can elicit a postactivation potentiation response to enhance forward 5-m sprint performance and to determine whether sled loading through a reduction in velocity can elicit an improvement in 5-m sprint performance. A randomized design was used to examine the effects of forward and backward sled tow loading of 35 and 55% reduction of individual's maximal velocity (rVelmean) on 5-m sprint performance. Eighteen well-trained male subjects performed 4 intervention sessions (55% rVelmean backward; 55% rVelmean forward; 35% rVelmean backward; and 35% rVelmean forward) separated by a minimum of 24 hours. Intervention sessions included baseline unresisted 5-m sprints, followed by 3 loaded sled tows over a distance of 3.2 m or 5 m for heavy and light loads, respectively. An unresisted 5-m sprint was completed after 6 and 12 minutes of rest. Mean sprint velocity, electromyography, sprint kinematic, and temporal data were collected during each session. Sled towing, irrespective of load or rest period, produced no significant change in 5-m sprint velocity (p > 0.05). In addition, there were no significant changes in electromyography, kinetic, and temporal data; however, current findings support previous research of confirming muscle activation and vertical force production during sprint acceleration. It is unclear whether individualizing a reduction in velocity is a superior method to percent body mass for optimizing sled loading in well-trained male subjects.
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Objectives This study aimed to establish and compare current physiotherapy management of GTPS in Australia, New Zealand (NZ) and Ireland. Design Cross-sectional observational survey of physiotherapists. Methods An online survey was distributed to registered musculoskeletal physiotherapists in Australia, NZ and Ireland. Ordinal and nominal data were analysed using frequency counts or mean ranks; median and interquartile ranges were calculated for numerical data. Inter-country comparisons were made using Chi-squared analyses for nominal/ordinal data and Kruskal–Wallis tests for numerical data. Statistical significance was set at P < 0.05. Results/findings Valid responses were received from 361 physiotherapists, 61% were female and 80% worked in private practice. Overall, consistency in treatment of GTPS was observed across the three countries. All physiotherapists used education and exercise (most commonly strengthening and neuromuscular control) primarily targeting the gluteal muscles. Other interventions included massage (90%), stretching (53%), range of motion (40%), thermal modalities (50%), taping (38%) and electrotherapy (25%), whilst 40% commonly recommended up to 2 to 3 corticosteroid injections per patient/per annum. Physiotherapists used pain severity scales as their primary outcome measure (79%). Single leg stance was the most common physical measure used (68%), and global rating scores or standardised physical measures were less commonly used. Conclusion This international survey established the physiotherapy management of GTPS. Education used in conjunction with exercise is in line with current evidence, but a proportion of clinicians use adjunct treatments without clear rationale or supporting evidence. Results indicate the need to further define optimal management of GTPS using robust methodologies such as randomised controlled trials.
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The energetic cost of running is relatively high in man. In spite of this, humans are adept endurance runners, capable of running down, for example, zebra and kangaroo. Distance running is made possible for man in part by an exceptional ability to dissipate exercise heat loads. Most mammals lose heat by panting, which is coupled to breathing and locomotor cycles during running. This interdependence may limit the effectiveness of panting as a means of heat dissipation. Because sweating is not dependent on respiration, it may be more compatible with running as a thermoregulatory mechanism. Furthermore, man's lack of body hair improves thermal conductance while running, as it facilitates convection at the skin surface. While horses, for example, have been shown to possess energetically optimal speeds in each gait, the energetic cost for a man to run a given distance does not change with speed. It is hypothesized that this is because bipedality allows breathing frequency to vary relative to stride frequency. Man's constant cost of transport may enable human hunters to pursue the prey animal at speeds that force it to run inefficiently, thereby expediting its eventual fatigue. Given what is known of heat dissipation in Old World Anthropoidea, the bipedality of early hominids, and human exercise physiology, one factor important in the origin of the Hominidae may have been the occupation of a new niche as a diurnal endurance predator.
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The human gluteus maximus is a distinctive muscle in terms of size, anatomy and function compared to apes and other non-human primates. Here we employ electromyographic and kinematic analyses of human subjects to test the hypothesis that the human gluteus maximus plays a more important role in running than walking. The results indicate that the gluteus maximus is mostly quiescent with low levels of activity during level and uphill walking, but increases substantially in activity and alters its timing with respect to speed during running. The major functions of the gluteus maximus during running are to control flexion of the trunk on the stance-side and to decelerate the swing leg; contractions of the stance-side gluteus maximus may also help to control flexion of the hip and to extend the thigh. Evidence for when the gluteus maximus became enlarged in human evolution is equivocal, but the muscle's minimal functional role during walking supports the hypothesis that enlargement of the gluteus maximus was likely important in the evolution of hominid running capabilities.
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Knowledge of the anthropometric parameters of the human body is essential for understanding of human kinetics and particularly for the design and testing of impact protective systems. Considerable information is available on the size, weight and center of mass of the body and its segments. This report supplements existing information with data regarding mass distribution characteristics of the human body as described by the principal moments of inertia and their orientation to body and segment anthropometry. The weight, center of mass location and principal moments of inertia of six cadavers were measured, the cadavers were then segmented and the mass, center of mass, moments of inertia and volume were measured on the fourteen segments from each cadaver. Standard and three-dimensional anthropometry of the body and segments was also determined.
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Paleoanthropologists have long argued-often contentiously-about the climbing abilities of early hominins and whether a foot adapted to terrestrial bipedalism constrained regular access to trees. However, some modern humans climb tall trees routinely in pursuit of honey, fruit, and game, often without the aid of tools or support systems. Mortality and morbidity associated with facultative arboreality is expected to favor behaviors and anatomies that facilitate safe and efficient climbing. Here we show that Twa hunter-gatherers use extraordinary ankle dorsiflexion (>45°) during climbing, similar to the degree observed in wild chimpanzees. Although we did not detect a skeletal signature of dorsiflexion in museum specimens of climbing hunter-gatherers from the Ituri forest, we did find that climbing by the Twa is associated with longer fibers in the gastrocnemius muscle relative to those of neighboring, nonclimbing agriculturalists. This result suggests that a more excursive calf muscle facilitates climbing with a bipedally adapted ankle and foot by positioning the climber closer to the tree, and it might be among the mechanisms that allow hunter-gatherers to access the canopy safely. Given that we did not find a skeletal correlate for this observed behavior, our results imply that derived aspects of the hominin ankle associated with bipedalism remain compatible with vertical climbing and arboreal resource acquisition. Our findings challenge the persistent arboreal-terrestrial dichotomy that has informed behavioral reconstructions of fossil hominins and highlight the value of using modern humans as models for inferring the limits of hominin arboreality.
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Running is a bouncing gait in which the body mass center slows and lowers during the first half of the stance phase; the mass center is then accelerated forward and upward into flight during the second half of the stance phase. Muscle-driven simulations can be analyzed to determine how muscle forces accelerate the body mass center. However, muscle-driven simulations of running at different speeds have not been previously developed, and it remains unclear how muscle forces modulate mass center accelerations at different running speeds. Thus, to examine how muscles generate accelerations of the body mass center, we created three-dimensional muscle-driven simulations of ten subjects running at 2.0, 3.0, 4.0, and 5.0m/s. An induced acceleration analysis determined the contribution of each muscle to mass center accelerations. Our simulations included arms, allowing us to investigate the contributions of arm motion to running dynamics. Analysis of the simulations revealed that soleus provides the greatest upward mass center acceleration at all running speeds; soleus generates a peak upward acceleration of 19.8m/s(2) (i.e., the equivalent of approximately 2.0 bodyweights of ground reaction force) at 5.0m/s. Soleus also provided the greatest contribution to forward mass center acceleration, which increased from 2.5m/s(2) at 2.0m/s to 4.0m/s(2) at 5.0m/s. At faster running speeds, greater velocity of the legs produced larger angular momentum about the vertical axis passing through the body mass center; angular momentum about this vertical axis from arm swing simultaneously increased to counterbalance the legs. We provide open-access to data and simulations from this study for further analysis in OpenSim at simtk.org/home/nmbl_running, enabling muscle actions during running to be studied in unprecedented detail.
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The shoulder bones of a juvenile australopith resemble those of extant apes, suggesting that tree climbing continued to be important for these bipedal early human ancestors.
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A method, which was found to be accurate within 0.54 m/s2, was developed to estimate the relative contributions of the net joint moments to forward progression and support in the gait of five normal subjects. Forward progression was produced primarily by the ankle plantar flexors with a significant assist from the knee extensors. Support was produced largely by the plantar flexors during single limb support and by a combination of ankle plantar flexors, knee extensors and hip extensors during double limb support.
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Numerous studies of the locomotor skeleton of the Hadar hominids have revealed traits indicative of both arboreal climbing/suspension and terrestrial bipedalism. These earliest known hominids must have devoted part of their activities to feeding, sleeping and/or predator avoidance in trees, while also spending time on the ground where they moved bipedally. In this paper we offer new data on phalangeal length and curvature, moφhology of the tarsus and metatarsophalangeal joints, and body proportions that further strengthen the argument for arboreality in the Hadar hominids. We also provide additional evidence on limb and pedal proportions and on the functional anatomy of the hip, knee and foot, indicating that the bipedality practiced at Hadar differed from that of modern humans. Consideration of the ecology at Hadar, in conjunction with modern primate models, supports the notion of arboreality in these earliest australopithecines. We speculate that selection for terrestrial bipedality may have intensified through the Plio-Pleistocene as forests and woodland patches shrunk and the need arose to move increasingly longer distances on the ground. Only with Homo erectus might body size, culture and other factors have combined to ‘release’ hominids from their dependence on trees.
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Some biomechanical characteristics of the pelvis and lower limb of Australopithecus afarensis (AL, 288-1) are compared with those of modern humans, in an attempt to define the pattern of australopithecine bipedal locomotion. The reconstruction of the pelvic and femoral morphology of AL 288-1 (Schmid, 1983) is used as a basic skeletal frame to infer (1) the loading constraints acting on the supporting hip; and (2) the action of some of the main muscles of the lower limb. The analysis reconstructs the placements of the australopithecine gluteal musculature, in the pattern of African pongids and of Homo . Only the reconstruction of the gluteal musculature on the basis of the pongid pattern is consistent with the bony, structure of the fossil and would have permitted effective movements of bipedalism. Moreover, the results clearly indicate that australopithecine bipedalism differs from that of humans. (1) The extended lower limb of australopithecines would have lacked stabilization during walking; and (2) the lower limb would have shown a greater freedom for motion, which can be interpreted as the retention of a partly arboreal behavior.
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The gluteal musculature of primates has been a focus of great research interest among those who study human evolution. Most current theorists agree that gluteus superficialis (= maximus) need not have changed its action in the step from pongid to hominid, but dispute has arisen over a purported change in action and role of the gluteus medius. To clarify the functions of gluteus medius, gluteus superficialis, and tensor fasciae femoris during ape locomotion, we conducted a telemetered electromyographic study of these muscles in two gibbons, one orangutan, and four chimpanzees as they walked bipedally on the ground and on a horizontal tree trunk, walked quadrupedally on the same substrates, and climbed a vertical tree trunk. The results indicate that the gluteus medius of apes is not, as has been previously suggested, primarily an extensor of the thigh; its action is chiefly that of medial rotation. The role of the gluteus medius during bipedality is the same in apes and humans–to provide side-to-side balance of the trunk at the hip. The change in the hominid lateral balance mechanism can be viewed as primarily osteological, allowing preservation of the same muscle function with an extended thigh. As a result, the stride length is increased and there occurs a diminution of the demands placed on other muscles to maintain anteroposterior balance at the hip and knee. Our data also support the view that vertical climbing may be specifically preadaptive to bipedalism. One may picture the earliest hominid as part biped, when on the ground traveling between scattered food trees, and part climber, when moving from the ground to food.
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Many anthropologists and anatomists have claimed that the human gluteus maximus is a functionally and structurally unique muscle, but there is not agreement on the actual characteristics of the muscle which do distinguish man from other primates. In this paper the superficial gluteus in a wide range of primates is discussed and those traits entirely unique to man are identified. The morphological specializations of the human gluteus maximus are confined to its cranial portion. This part is thicker in man than in any other primate; it has a new and firm origin, a modified ascending tendon of insertion, and an additional new insertion into the overlying fascia lata. Such changes improve the ability of the gluteus maximus to participate in controlling lateral stability of the trunk, and it suggested that this is the function which has been selected for in human evolution.