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Does segment length influence the hip, knee and ankle coordination during the squat movement?

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Abstract

Background: The back squat exercise is a common and essential clinical rehabilitation exercise. As a compound movement of the lower limbs the cues to optimal movement technique are complex and difficult to identify. The aim of this study was to determine the influence of lower limb segment lengths on the biomechanics of movement when performing the back squat exercise. Methods: Using 3D kinematic analysis the 28 subjects (male n= 16, female n= 12) performed four sets of eight squats. The four independent variables were: load – (i) body-weight with no external load, and (ii) body-weight plus 50% body-weight external load; and width of stance – (iii) narrow stance equal to ASIS width; and (iv) wide equal to twice ASIS width. Findings: The total squat pattern was different for genders and limb length correlations showed that genders created movement patterns of the lower body in squatting, which may have resulted due to these limb length differences. Males typically lean more forward allowing their spine to create greater movement and depth during the squat. Females utilise the knees and sacrum to adjust for depth, achieve greater hip flexion, and remain upright during the squat. The frequent correlations for limb lengths with the knees in females suggest females utilise the knees as a strategy to maintain synchronisation of the squat. Interpretation: Taller women typically achieved greater knee angles, and taller men achieved smaller hip angles. Males and females do create different movement strategies for the squat movement and coaches and trainers should allow for this in both teaching and cueing of the squat movement pattern.
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... Similar to the box lifting study of Trafimow et al. (1993), the transferability of these observations to the atlas stone lift are uncertain due to the substantial difference in loading (male: 12.8 kg; female: 8.7 kg) and study populations (healthy office employees) compared to male and female strongman athletes performing the atlas stone lift. Of greater relevance to the atlas stone lift may be the studies of McKean & Burkett (2012) and Lisman et al. (2021), where between-sex kinematic differences were observed in trained persons performing the back squat (50% body mass) and over-head squat (un-loaded), respectively. In these studies, female athletes displayed a more upright trunk position during the overhead squat (Lisman et al., 2021) and back squat (McKean & Burkett, 2012) than male athletes. ...
... Of greater relevance to the atlas stone lift may be the studies of McKean & Burkett (2012) and Lisman et al. (2021), where between-sex kinematic differences were observed in trained persons performing the back squat (50% body mass) and over-head squat (un-loaded), respectively. In these studies, female athletes displayed a more upright trunk position during the overhead squat (Lisman et al., 2021) and back squat (McKean & Burkett, 2012) than male athletes. Male athletes displayed greater peak hip flexion in the overhead squat than female athletes (Lisman et al., 2021), while females displayed greater peak hip flexion in the back squat than male athletes (McKean & Burkett, 2012). ...
... In these studies, female athletes displayed a more upright trunk position during the overhead squat (Lisman et al., 2021) and back squat (McKean & Burkett, 2012) than male athletes. Male athletes displayed greater peak hip flexion in the overhead squat than female athletes (Lisman et al., 2021), while females displayed greater peak hip flexion in the back squat than male athletes (McKean & Burkett, 2012). ...
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Background The atlas stone lift is a popular strongman exercise where athletes are required to pick up a large, spherical, concrete stone and pass it over a bar or place it on to a ledge. The aim of this study was to use ecologically realistic training loads and set formats to (1) establish the preliminary biomechanical characteristics of athletes performing the atlas stone lift; (2) identify any biomechanical differences between male and female athletes performing the atlas stone lift; and (3) determine temporal and kinematic differences between repetitions of a set of atlas stones of incremental mass. Methods Kinematic measures of hip, knee and ankle joint angle, and temporal measures of phase and repetition duration were collected whilst 20 experienced strongman athletes (female: n = 8, male: n = 12) performed three sets of four stone lifts of incremental mass (up to 85% one repetition maximum) over a fixed-height bar. Results The atlas stone lift was categorised in to five phases: the recovery, initial grip, first pull, lap and second pull phase. The atlas stone lift could be biomechanically characterised by maximal hip and moderate knee flexion and ankle dorsiflexion at the beginning of the first pull; moderate hip and knee flexion and moderate ankle plantarflexion at the beginning of the lap phase; moderate hip and maximal knee flexion and ankle dorsiflexion at the beginning of the second pull phase; and maximal hip, knee extension and ankle plantarflexion at lift completion. When compared with male athletes, female athletes most notably exhibited: greater hip flexion at the beginning of the first pull, lap and second pull phase and at lift completion; and a shorter second pull phase duration. Independent of sex, first pull and lap phase hip and ankle range of motion (ROM) were generally smaller in repetition one than the final three repetitions, while phase and total repetition duration increased throughout the set. Two-way interactions between sex and repetition were identified. Male athletes displayed smaller hip ROM during the second pull phase of the first three repetitions when compared with the final repetition and smaller hip extension at lift completion during the first two repetitions when compared with the final two repetitions. Female athletes did not display these between-repetition differences. Conclusions Some of the between-sex biomechanical differences observed were suggested to be the result of between-sex anthropometric differences. Between-repetition differences observed may be attributed to the increase in stone mass and acute fatigue. The biomechanical characteristics of the atlas stone lift shared similarities with the previously researched Romanian deadlift and front squat. Strongman athletes, coaches and strength and conditioning coaches are recommended to take advantage of these similarities to achieve greater training adaptations and thus performance in the atlas stone lift and its similar movements.
... However, correlation of these values with squat depth indicate that there was no statistically significant relationship between them. A previous study by Mckean and Burkett reported that body height can be related to kinematic parameters in males and females during the two-leg back squat 48 . Thus, anthropometric parameters seem to be linked to SLS depth affecting kinematics. ...
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... This is consistent with the findings of McKean et al., who showed a similar relation in the timing of lumbar flexion (McKean et al., 2010b) This author also reported that maximum hip and knee angles are achieved almost simultaneously with the deepest part of the squat (M. McKean and Burkett, 2012). To the best of the authors' knowledge, this is the first report of a correlation between the timing parameters of joints' motion and squat depth. ...
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... The traditional back squat is frequently used in training programs to activate and strengthen both the anterior and posterior chain (6). It has been shown that men and women do adopt different movement patterns during the traditional back squat, which could initiate the activation of different musculature during squat execution and have exercise prescription implications (12,19). Currently, the physiological explanation for this disparity is unknown because analysis from the aforementioned study was limited to the kinematic variables of the back squat and reports of the muscle activation patterns of women during the traditional back squat are sparse (4). ...
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Mehls, K, Grubbs, B, Jin, Y, and Coons, J. Electromyography comparison of sex differences during the back squat. J Strength Cond Res XX(X): 000-000, 2020-Currently, there is limited information regarding the muscle activity differences between men and women during the traditional back squat. The back squat is a widely used exercise which stimulates lower-body musculature; thus, information regarding the muscle activity patterns during this exercise is pertinent when prescribing resistance training. This study evaluated muscle activity differences (using surface electromyography) in men and women during the traditional back squat with a load prescribed to elicit strength gains. Resistance-trained men (n = 14) and women (n = 14) performed 3 sets of 4 repetitions in the traditional back squat using 85% of their pretest 1 repetition maximum. Muscle activity data were collected for 6 muscles including the vastus lateralis, vastus medialis, rectus femoris, gluteus maximus, semitendinosus, and biceps femoris (BF). Independent sample t tests revealed a significantly higher normalized muscle activity men in the BF muscle during the descending phase of the back squat. No other muscle activity differences were present between men and women. These results indicate that men activate the BF muscle during the traditional back squat to a greater extent than women. For women, it may be necessary to consider other exercises to optimally stimulate and strengthen the BF muscle during resistance training.
... Further-329 more, in this study the loads were not balanced for 330 comparison of deep and partial squats, which might 331 have compromised the results. needed to fill in this gap [21]. 374 ...
... Furthermore, most studies examining muscle activity during lower-body resistance training have included predominantly male participants leading a potential void in the literature for the female population (8). Finally, anthropometric and kinematic differences between sexes exist, so future research is needed to fill in this gap (19). ...
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... Furthermore, most studies examining muscle activity during lower-body resistance training have included predominantly male participants leading a potential void in the literature for the female population (8). Finally, anthropometric and kinematic differences between sexes exist, so future research is needed to fill in this gap (19). ...
... Furthermore, most studies examining muscle activity during lower-body resistance training have included predominantly male participants leading a potential void in the literature for the female population (7). Finally, anthropometric and kinematic differences between sexes exist, so future research is needed to fill in this gap (18). ...
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... Although the unilateral exercises used in the study are not direct comparisons with either FW or SM bilateral squats, they are indications that there are possible gender differences during the squat movement. Similarly, in 2 separate studies, McKean et al. observed that men and women exhibit different movement patterns during the squat exercise, possibly because of dissimilar lumbar and sacrum movement (24) and potential differences in lower limb length (23). ...
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