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Biomechanical, Anthropometric, and Psychological Determinants of Barbell Back Squat Strength

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Previous investigations of strength have only focused on biomechanical or psychological determinants, while ignoring the potential interplay and relative contributions of these variables. The purpose of this study was to investigate the relative contributions of biomechanical, anthropometric, and psychological variables to the prediction of maximum parallel barbell back squat strength. Twenty-one college-aged participants (male = 14; female = 7; age = 23 ± 3 years) reported to the laboratory for two visits. The first visit consisted of anthropometric, psychometric, and parallel barbell back squat one-repetition maximum (1RM) testing. On the second visit, participants performed isometric dynamometry testing for the knee, hip, and spinal extensors in a sticking point position-specific manner. Multiple linear regression and correlations were used to investigate the combined and individual relationships between biomechanical, anthropometric, and psychological variables and squat 1RM. Multiple regression revealed only one statistically predictive determinant: fat free mass normalized to height (standardized estimate ± SE = 0.6 ± 0.3; t(16) = 2.28; p = 0.037). Correlation coefficients for individual variables and squat 1RM ranged from r = -0.79-0.83, with biomechanical, anthropometric, experiential, and sex predictors showing the strongest relationships, and psychological variables displaying the weakest relationships. These data suggest that back squat strength in a heterogeneous population is multifactorial and more related to physical rather than psychological variables.
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... At the time this study was conducted, several studies had determined the influence of various physical aspects of its competitors on powerlifting performance, namely on anthropometry (15,30,32,38,61), fat-free mass (4, 15,16,61), skeletal muscle mass (65) and bone mass (16). Granted, most of these studies had not been conducted on classic powerlifters, as most of them were carried out at a time when there was little to no differentiation between classic and equipped lifting. ...
... At the time this study was conducted, several studies had determined the influence of various physical aspects of its competitors on powerlifting performance, namely on anthropometry (15,30,32,38,61), fat-free mass (4, 15,16,61), skeletal muscle mass (65) and bone mass (16). Granted, most of these studies had not been conducted on classic powerlifters, as most of them were carried out at a time when there was little to no differentiation between classic and equipped lifting. ...
... The first study showed that arm circumference and arm muscle cross-sectional area as well as thigh circumference presented strong relationships with strength in the three powerlifting events in highly trained football players (36) and the second showed that selected upper arm cross-sectional area, body fat percentage and chest circumference (torso) were the best items to predict bench press strength in college males (35). Another study published by Vigotsky et al. also presented significant relationships between parallel back squat strength and fat-free mass normalized to height as well as anthropometry (61). ...
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International Journal of Exercise Science 13(4): 1512-1531, 2020. Several studies have determined the influence of physical characteristics on strength. The present quantified the relationships between anthropometry and maximal strength. Male classic powerlifters (n=59) were measured before a championship. Two-tailed Pearson correlation analysis was used. Powerlifters that presented higher relative maximal strength (RMS) in the squat and bench generally had higher body weight (BW), body mass index (BMI), torso circumference (C), waist C/height, torso C/height (r=0.26 to 0.49, p<0.05), and smaller lower leg length (L)/height and forearm L/torso C (r=-0.31 to-0.45, p<0.05) ratios. Powerlifters with a higher % of their deadlift on their total generally presented a smaller BW, BMI, body fat percentage (BF%), waist and torso C, trunk L, waist C/height, torso C/height, trunk L/height, waist C/hip C, thigh L/ lower leg L, trunk L/thigh L ratios (r=-0.26 to-0.49, p<0.05) and higher lower leg L, lower leg L/height, reach/height, and forearm L/torso C ratios (r=0.32 to 0.51, p<0.05). Stepwise regressions revealed that a bigger torso positively predicted absolute maximal strength (AMS) in the squat (β=0.41, p=0.04), the bench (β=0.77, p<0.01), the deadlift (β=0.88, p<0.01) and the total (β=0.89, p<0.01), that a higher torso C/height ratio positively predicted RMS in the squat(β=0.48, p<0.01), the bench (β=-0.87, p<0.01) and the total (β=0.66, p<0.01), and that reach/height positively predicted RMS in the deadlift (β=0.37, p<0.01) and it's % on the total (β=0.31, p<0.01), but negatively predicted RMS in the bench (β=-0.25, p=0.02) and its % on the total (β=-0.24, p=0.04) As all of the stronger correlations came from AMS, powerlifters should focus on increasing AMS (weight lifted) instead of RMS (Wilks pts).
... During resistance training, when the load cannot be moved all the way upwards it is considered a failed repetition, and this often occurs in the so-called sticking region ( Van den Tillaar et al., 2014;Saeterbakken et al., 2016;Vigotsky et al., 2019). A sticking region has been repeatedly observed in the squat in numerous studies. ...
... The sticking region is defined as the part of the range of motion in which a disproportionally large increase in difficulty occurs and is considered a mechanical constraint (Kompf and Arandjelović, 2016;. This leads to a decrease in the upward velocity of the barbell ( Van den Tillaar et al., 2014;Saeterbakken et al., 2016) and an increase in the chances of exercise form breakdown (Schoenfeld, 2010;Kompf and Arandjelović, 2016;Vigotsky et al., 2019). After this region, in the post sticking region velocity increases again due to more favorable biomechanical conditions ( Van den Tillaar et al., 2014;Saeterbakken et al., 2016;Andersen et al., 2016). ...
... A high-bar back squat (bar placed across the shoulder on the trapezius, slightly above the posterior aspect of the deltoids) (Schoenfeld, 2010;Vigotsky et al., 2019) to a parallel depth (Clark et al., 2012;Bryanton et al., 2012;Saeterbakken et al., 2016) was performed. The stance width was established for each subject between the hips and shoulder (Schoenfeld, 2010). ...
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Modifying basal elongation of elastic bands (EB) has been proven useful to increase some parameters of the intensity in variable resistance training. Therefore, the question arises as to whether the pertinent resistance could be applied with EB immediately above the sticking point in squat exercises to optimize the performance. The purpose was to analyze some variables of the external (kilograms and number of repetitions) and internal load (heart rate, blood pressure, and rate of perceived exertion) after six different conditions of the squat exercise when using weight plates (WP) or EB (placed at different points of the range of motion) and applying maximal or submaximal effort. Twenty physically active males (25.50 ± 5.26 yrs) underwent two sessions for familiarization and one for assessment. The six conditions (three with WP and three with EB) were randomly performed. The sticking point of each subject was measured using the knee joint angle and the resistance was applied with EB at this height. Immediately after finishing each set subjects reported perceived effort rate and cardiovascular measurements were taken. Repetitions completed, and kilograms used were recorded. Repeated measures testing evaluated differences between conditions. EB permitted performing 8 more repetitions compared to WP when the same load was added at standing position. Adding the load immediately above the sticking point significantly (p < 0.05) increased 24.7% the kilograms used and permitted participants to perform 3 more repetitions. Internal load measurements suggested that EB could significantly (p < 0.05) reduce the perceived effort rate and/or physiological stress depending on their application. EB are a suitable device to load the bar for squat exercises in fit young men. According to the necessities of the subjects, if the load with EB is added at different points of the range of motion, it could be possible to overcome the sticking point, to maximize the performance and/or modulate cardiovascular and perceptual responses.
... The squat is one of the most commonly used resistance exercises for performance and health due to its biomechanical and neuromuscular similarities to a wide range of athletic and everyday activities (Andersen et al., 2016;Clark et al., 2012;Kompf & Arandjelović, 2017;Schoenfeld, 2010). All variants of the squat involve synergistic hip, knee, and ankle flexion in the descent, followed by knee and hip extension in the ascent which finishes with the individual in the starting position (Clark et al., 2012;Escamilla et al., 2001;Iversen et al., 2017;Schoenfeld, 2010;Vigotsky et al., 2019). However, there is a large number of squat variations (based on the descent depth, the width of the stance, bar placement, orientation of the knee flexion planes, and so on) with significant biomechanical and neuromuscular differences between them (Clark et al., 2012;Kompf & Arandjelović, 2017;Schoenfeld, 2010;Van den Tillaar et al., 2014). ...
... Some squat variations found in the literature and excluded from the analysis were the unilateral squat, Bulgarian squat, and wall squat. The five squat variations included were (see Figure 2): S1280 | 2020 | Proc4 | VOLUME 15 © 2020 University of Alicante High-bar squat (26 studies): the bar is placed across the shoulder on the trapezius, slightly above the level of the acromion and the posterior aspect of the deltoids (Schoenfeld, 2010;Vigotsky et al., 2019;Wretenberg et al., 1996). ...
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The squat is one of the most commonly used resistance exercises for performance and health due to its biomechanical and neuromuscular similarities to a wide range of athletic and everyday activities. There is a large number of squat variations (based on the descent depth, width of the stance, bar placement) with significant biomechanical and neuromuscular differences between them. The aim of this study was to systematically review the scientific literature to gather data on the muscular activation of the lower limb during different variants of the squat exercise. High-bar squat (full range of motion, to parallel and partial range of motion), low-bar squat, front squat, overhead squat and guided squat on Smith machine were included in the analysis. 30 articles met the inclusion criteria and were reviewed. Quality of the included studies was analysed with the PEDro scale. Main findings were that in the squat exercise activation of the knee-extensors is predominant. However, different activation patterns were observed with different distances between the feet, different depths, hips rotation or flexion, intensities. For instance, low-bar squat involves a greater hip hinge and thus, provokes major activation on the hip-extensors than other squat variations. It is worth highlighting that similar activation patterns were observed between the front squat and the high-bar squat. The variation with least activation was the guided squat. The evidence presented in this study may help the strength and conditioning professionals and practitioners with the exercise selection depending on the muscular targets and the individual characteristics of the athlete. Keywords: Electromyographic activity; Resistance exercise; Quadriceps; Gluteus; Hamstrings; Calves.
... Some studies have shown an association of either the height or length of certain body segments with the absolute strength performance in some exercises (Ferland, Laurier et al., 2020;Ferland, Pollock et al., 2020;Ford et al., 2000;Fuster et al., 1998;Mayhew et al., 1993;Vigotsky et al., 2019). As far as we know, this was the first study to verify the correlation between the eccentric knee flexor strength during the NHE with the participants' height. ...
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The study aimed to verify how age, height, body mass and body mass index affects the eccentric knee flexor strength during the Nordic hamstring exercise (NHE) in male soccer players. Ten professional soccer clubs were included in this cross-sectional trial. Three hundred and eleven soccer players (192 from senior and 119 from under-20 teams) were assessed using a load-cell based device. Pearson’s correlation tests were performed between peak force values (measured in Newtons) and age, height, body mass and body mass index. The individual-limb strength (n = 622 limbs) and the between-limb average strength (n = 322 players) presented no correlation with age (r = 0.12 for both) and height (r = 0.13; r = 0,15), and fair correlations with body mass (r = 0.37; r = 0,41) and body mass index (r = 0.40; r = 0,43). In conclusion, the male soccer players’ eccentric knee flexor strength measured during the NHE execution is not affected by age or height. Body mass and body mass index play somewhat effect on strength, thus normalising absolute strength measures by body mass or body mass index can provide more accurate analysis in some contexts.
... In support of this theory, Jenkins et al. [8] demonstrated greater increases in percent voluntary muscle activation and electromyographic amplitude when performing leg extension RT to failure with 80% 1RM compared to 30% 1RM over a 6-week study period. Psychological factors are believed to be involved as well, as repeated heavy load lifting may help lifters acclimate to exerting a maximal effort; however, the psychological contribution to strength-related adaptations remains equivocal [9]. ...
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Loading recommendations for resistance training are typically prescribed along what has come to be known as the “repetition continuum”, which proposes that the number of repetitions performed at a given magnitude of load will result in specific adaptations. Specifically, the theory postulates that heavy load training optimizes increases maximal strength, moderate load training optimizes increases muscle hypertrophy, and low-load training optimizes increases local muscular endurance. However, despite the widespread acceptance of this theory, current research fails to support some of its underlying presumptions. Based on the emerging evidence, we propose a new paradigm whereby muscular adaptations can be obtained, and in some cases optimized, across a wide spectrum of loading zones. The nuances and implications of this paradigm are discussed herein.
... However, in terms of relative strength, the shorter a weightlifter is, the higher his strength will be [12,32]. This is because the body is primarily composed of third class levers, therefore, the longer the bony segments, the greater the work and torque the lifter requires to lift the barbell [34,35]. Moreover, weightlifters can be expected to be heavier than age-matched individuals in the general population [32,36]. ...
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Weightlifting is a discipline where technique and anthropometric characteristics are essential to achieve the best results in competitions. This study aims to analyse the relationships between body composition, limb length and barbell kinematics in the performance of weightlifters. It consists of an observational and descriptive study of 19 athletes (12 men [28.50 ± 6.37 years old; 84.58 ± 14.11 kg; 176.18 ± 6.85 cm] and 7 women [27.71 ± 6.34 years old; 64.41 ± 7.63 kg; 166.94 ± 4.11 cm]) who met the inclusion criteria. A level I anthropometrist took anthropometric measures according to the methodology of the International Society for the Advancement of Kinanthropometry (ISAK), and the measurement of the barbell velocity was made with the software Kinovea. In terms of body composition, both genders are within the percentage range of fat mass recommended for this sport. In female weightlifters, there is a positive correlation between foot length, maximal velocity in the Snatch (ρ = 0.775, p = 0.041), and performance indicator in the Snatch and the Clean & Jerk (ρ = 0.964, p < 0.001; ρ = 0.883, p = 0.008, respectively). In male weightlifters, a positive correlation between tibial length and average velocity of the barbell in the Snatch is observed (ρ = 0.848, p < 0.001). Muscle mass percentage correlates positively with performance indicator in both techniques (ρ = 0.634, p = 0.027; ρ = 0.720, p = 0.008). Also, the relative length of the upper limb is negatively correlated with the performance indicator (ρ = −0.602, p = 0.038). Anthropometry and body composition may facilitate skill acquisition among this sport population, contributing to increase the limited body of scientific knowledge related to weightlifting.
... Furthermore, all subjects were required to have a barbell squat 1RM $1.5 times their body mass (reported at the initial screening visit). This value was chosen to prevent inexperienced individuals from entering the investigation and was conservatively based on previous body mass scaled back squat performance data in college-aged men (35). All subjects were screened for their previous knee sleeve use, whereby those with major experience or a discernible preference toward knee sleeves were excluded to prevent potential condition biases. ...
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Neoprene knee sleeves are commonly employed by powerlifters and recreational users, but are heavily under-researched. Furthermore, no data exist on whether knee sleeves of varying compressive tightness impact muscular performance similar to commonly used knee wraps, which are both generally effective and more so when increasingly constrictive. Fifteen resistance trained, knee sleeve-naïve, recreational weight lifting males (22.1±4.1y; 177.5±5.9cm; 87.8±7.8kg) visited the laboratory on three separate occasions one week apart, assigned in a randomized, crossover, and counterbalanced fashion to either a minimally-supportive control condition knee sleeve (CS), manufacturer-recommended sizing neoprene knee sleeve (NS), or a one-size smaller (than NS) neoprene knee sleeve (TS). On each visit, subjects sequentially completed vertical jump (countermovement and squat jumps for both peak and mean power), one-repetition maximum (1RM) barbell squat and GymAware assessments (peak power, peak velocity, and dip) at 90% (reported) and 100% (tested) 1RM, as well as one-leg extension (1RM, repetitions to failure and total volume-load at 75%1RM) tests. All data was analyzed via one-way repeated measures ANOVA at p<.05. Analysis revealed a significant condition effect on barbell squat 1RM (p=.003; η2=.339) , whereby both NS (p=.044; 166±24kg) and TS (p=.019; 166±21kg) outperformed CS Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation (161±22kg), with no difference between neoprene sleeves. Conversely, no other tested parameters differed between knee sleeve conditions (p > .05). The present results demonstrate that neoprene knee sleeves may function independent of tightness, relative to recommended sizing and ultimately unlike knee wraps. Furthermore, the singular benefits observed on barbell squat maximal strength potentially suggests an exercise-specific benefit yet to be fully elucidated.
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Background The aim was to determine the relationship between the cross-sectional area of the quadriceps femoris and strength performance in the deep and parallel barbell squat. Methods The sample included 16 university students (seven female, 24.1 ± 1.7 years). Muscle strength was expressed as external load, including the one-repetition maximum and the body mass segments involved (calculated according to Dempster’s method). The cross-sectional area of the quadriceps femoris muscles was determined using ultrasound, while leg muscle mass was measured using the Bioelectrical Impedance method. Results The cross-sectional areas of the three vastii muscles and leg muscle mass showed moderate to strong correlation with external load in both squat types ( r = 0.509–0.873). However, partial correlation (cross-sectional area of quadriceps femoris muscles were controlled) showed significant association only between leg muscle mass and deep squat ( r = 0.64, p < 0.05). The cross-sectional area of the vastus lateralis showed a slightly higher correlation with external load in the parallel than in the deep squat ( r = 0.67, p < 0.01 vs. r = 0.59, p < 0.05). The regression analysis extracted the vastus medialis cross-sectional area as the most important factor in manifesting strength (parallel squat: R ² = 0.569; deep squat: R ² = 0.499, both p < 0.01). The obtained results suggest that parallel squat strength depends mainly on the cross-sectional area of the vastii muscles, while it seems that the performance in the deep squat requires an additional engagement of the hip and back extensor muscle groups.
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In strength training, personalised strength training (autoregulation) approaches have been used to individualise exercise programs with monitoring an for dynamic adjustment based on their responses to training. While this transition from tradition-based training to evidence-based training framework has been an improvement in training practices, we argue that the future of strength training will also incorporate deep learning models powered by data. We refer to this data-driven framework as precision strength training inspired by the similar modeling frameworks used in precision medicine. In contrast to current personalised training in which the acquired athlete data is often subject to human expert decision-making, we are anticipating the rise of human-in-the-loop systems with an augmented coach who will be doing decisions collaboratively with the machine. Similar to other precision frameworks, such as precision health, we envision such a future to take decades to be realised and we focus here on practical short-term targets on a way to long-term realisation. In this chapter, we will review the measurement technology needed for continuous data acquisition from an individual during training/physical activity, how to acquire these datasets for the development of such systems and, how a proof-of-concept system could be developed for powerlifting training with applicability to general strength and conditioning (S&C) and physical rehabilitation purposes. Additionally, we will evaluate how the user experience (UX) of the system feedback and visualisation could be designed.
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