Barbell Back Squat Research Articles

Effects of barbell back squat stance width on sagittal and frontal hip and knee kinetics.

Different stance widths are commonly utilized when completing the barbell back squat during athletic general preparedness training. Width manipulation is thought to influence sagittal plane stimuli to the hip and knee extensors, the primary extensor musculature in the squat. However, how width manipulation affects frontal plane stimuli is less understood. Knowledge of hip and knee net joint moments (NJM) could improve exercise selection when aiming to improve sport-specific performance and prevent injuries. Fourteen adult amateur rugby athletes were recruited for this study. After a familiarization period, participants performed wide- (WIDE, 1.5× greater trochanter width) and narrow-stance (NARROW, 1× greater trochanter width) barbell back squats to femur parallel depth, using relative loads of 70% and 85% of one-repetition maximum. Sagittal and frontal plane hip and knee kinetics and kinematics were compared between widths. A Bonferroni-corrected alpha of 0.01 was employed as the threshold for statistical significance. Knee flexion angle was statistically greater in NARROW than WIDE (P<0.0001, d=2.56-2.86); no statistical differences were observed for hip flexion angle between conditions (P=0.049-0.109, d=0.33-0.38). Hip-to-knee extension NJM ratios and knee adduction NJMs were statistically greater in WIDE than NARROW (P<0.007, d=0.51-1.41). At femur parallel, stance width manipulation in the barbell back squat may provide substantial differences in biomechanical stimulus in both the sagittal plane and the frontal plane. In certain contexts, these differences may have clinically relevant longitudinal implications, from both a performance and a injury prevention standpoint, which are discussed.

Show Me, Tell Me, Encourage Me: The Effect of Different Forms of Feedback on Resistance Training Performance.

Weakley, J, Wilson, K, Till, K, Banyard, H, Dyson, J, Phibbs, P, Read, D, and Jones, B. Show me, tell me, encourage me: The effect of different forms of feedback on resistance training performance. J Strength Cond Res 34(11): 3157-3163, 2020-When performing resistance training, verbal kinematic feedback and visual kinematic feedback are known to enhance performance. In addition, providing verbal encouragement can assist in the attenuation of fatigue. However, the effects of these forms of feedback have never been compared. Consequently, this study aimed to quantify the effects of verbal kinematic feedback and visual kinematic feedback, and verbal encouragement on barbell velocity during the back squat. Furthermore, changes in performance were related to individual-reported conscientiousness. Twelve semiprofessional rugby union players volunteered to participate in the study that consisted of the subjects completing a set of the barbell back squat across 4 conditions (i.e., no-feedback [control], verbal feedback of kinematic information [verbal], visual feedback of kinematic information [visual], and verbal encouragement [encouragement]). In addition, participants completed a questionnaire before the study to assess conscientiousness. Magnitude-based inferences were used to assess differences between conditions, whereas Spearman's rank correlation coefficient was used to assess relationships between conscientiousness and changes in barbell velocity. All 3 forms of feedback showed almost certain improvements in barbell velocity, while differences between interventions were likely to very likely trivial. Changes in barbell velocity showed small to large inverse relationships with conscientiousness. These findings suggest that practitioners should supply kinematic feedback (verbally or visually) or, when technology is not available, provide athletes with encouraging statements while resistance training. Verbal encouragement may be of greatest benefit for individuals who demonstrate low levels of conscientiousness. Given these findings, practitioners are advised to use either technology or verbal encouragement to manipulate acute training outcomes.

Myofibrillar Protein Synthesis to Traditional and Cluster Sets in Trained Young Men and Women

During traditional (TRD) resistance exercise, there is a decrease in the velocity and power output achieved over the course of a set consisting of multiple repetitions. Reconfiguration of an exercise set into a cluster set (CLU), which includes a brief intra-set rest period, has been shown to counteract this performance decline. However, the effect of intra-set rest manipulations during resistance exercise on changes in postexercise myofibrillar protein synthesis rates (MPS) is not clear. PURPOSE: We determined if any differences exist in the stimulation of postexercise MPS to acute bouts of CLU and TRD paradigms of barbell back squats. METHODS: In crossover trials, 5 resistance trained men and women (23±2 y; LBM: 60±5 kg; 1RM back squat: 143±13 kg) performed CLU or TRD configurations of barbell back squats and ingested 20 g whey protein before and immediately after exercise. Blood and muscle biopsy samples were collected at rest and after exercise during primed continuous L-[ring-13C ]phenylalanine infusions. The TRD condition consisted of 4 sets × 10 repetitions with 120 seconds inter-set rest. CLU condition consisted of 4 sets × (2 × 5) repetitions with 90 seconds inter- set rest and 30 seconds intra-set rest at ~70% of 1RM. Mean and peak velocity were measured for all repetitions. RESULTS: Volume load (repetitions × load) was matched between the TRD (8400±39 kg) and CLU conditions (8400±39 kg; P=XX)). CLU condition tended to allow for greater mean velocities versus TRD condition over the 4 sets (0.52±0.02 m/s and 0.47±0.02 m/s, respectively). The cumulative (0-5 h) MPS were increased (P<0.05) above basal in both TRD (237%) and CLU conditions (215%) with no difference between conditions (P=0.72). However, the temporal pattern of change in MPS tended to be greater in the TRD conditions versus CLU condition (P=0.10). CONCLUSION: These data showed that both TRD and CLU configurations of barbell back squat augment postexercise MPS throughout 0-5 h of recovery in trained young men and women. These data indicate that the intra-set rest manipulations present in CLU do not induce differences in muscle anabolism from TRD-style of resistance exercise in trained young men and women.

Influence of Attentional Focus in a Weighted Barbell Back Squat Among Experienced Performers

Influence of Attentional Focus in a Weighted Barbell Back Squat Among Experienced Performers

Comparison of Strength Gains in Untrained College-Age Females Using Free Weights and FreeMotion Machines

Resistance training has become a preferred method for developing muscular strength among various populations. A variety of resistance training modes are available, but there are mixed outcomes regarding strength development among barbells, dumbbells, and weight machines. The purpose of this study was to investigate the differences in strength improvements between dumbbell and FreeMotion machine training. Twenty college-age females were randomly assigned into dumbbell or FreeMotion groups, but only 8 in the dumbbell group completed. Both groups followed a nearly identical progressive strength training program on each of their training modes for 8 weeks. Participants were tested on their one-repetition max (1-RM) on a barbell bench press and barbell back squat before and after the intervention program. A repeated measures ANOVA analysis compared 1-RM changes between groups, and effect sizes were calculated. Significant increases in strength improvements (p < .001) were observed for the dumbbell and FreeMotion groups, with moderate effect size for the 1-RM barbell bench press (d = 0.56) and a moderate to large effect size for the 1-RM barbell back squat (d = 0.73). There was no Group × Time interaction for the strength tests (p = .201 for 1-RM barbell bench press and p = .816 for the 1-RM barbell back squat, respectively). Dumbbells and FreeMotion machines were equally effective in improving strength in college-age females. The findings add to the literature on FreeMotion machines and benefit novice resistance trainers, physical educators, and fitness professionals. The study should be replicated with additional populations. Subscribe to TPE

Effect of Hip Abduction Maximal Voluntary Isometric Contraction on Lumbar Motion and Power Output During the Back Squat

Background: Post-activation potentiation (PAP) is a neuromuscular phenomenon that has been shown to augment muscular force generating attributes as well as neural and sensory recruitment. While PAP has demonstrated to acutely enhance muscular performance during high-intensity activities, the effect of PAP on lumbopelvic kinematics under load remains unknown. Objectives: The purpose of this study was to examine the potential PAP effect of a hip abduction maximal voluntary isometric contraction (MVIC) on lumbar motion and power output during the barbell back squat. Methods: Nine resistance-trained men (22.9±2.3 y; 85.0±13.8 kg; 174.3±5.1 cm) performed a set of 5 repetitions of the barbell back squat using 80% one-repetition maximum with and without a hip abduction MVIC prior to performance. Experimental and control trials were randomized and counterbalanced among participants. MVIC was carried out via manual long-lever hip abduction. During the back squat exercise, lumbar motion analysis was performed using wireless motion-sensor technology, and power output was assessed via an accelerometer. Results: No significant differences were observed between trials for lumbar flexion range of motion (ROM) (p=0.32), lumbar flexion maximum deviation (p=0.32), lumbar lateral flexion ROM (p=0.81), lumbar lateral flexion maximum deviation (p=0.98), lumbar rotation maximum deviation (p=0.70), average peak power (p=0.98), or average mean power output (p=0.99) during the squat protocol. Conclusions: Implementation of a manual long-lever hip abduction MVIC prior to the back squat exercise did not significantly alter lumbar motion or augment power output in resistance trained males.

Effect of Ankle Mobility and Segment Ratios on Trunk Lean in the Barbell Back Squat.

Fuglsang, EI, Telling, AS, and Sørensen, H. Effect of ankle mobility and segment ratios on trunk lean in the barbell back squat. J Strength Cond Res 31(11): 3024-3033, 2017-The barbell back squat is a popular exercise used for both performance enhancing and rehabilitation purposes. However, injuries are common, and people with a history of lower back pain are especially vulnerable. Past studies have shown that higher trunk angles (less forward lean) generate less stress on the lower back; thus, it seems appropriate to investigate the factors presumed to influence the trunk angle. Therefore, the aim of this study was to investigate how ankle mobility and the segment ratios between the thoracic spine, thighs, and shanks influence the trunk angle in the back squat. While recorded with motion capture, 11 male subjects performed 3 repetitions at approximately 75% of 1 repetition maximum in the squat to a parallel position (thighs horizontal) or lower. Furthermore, subjects performed a weight bearing lunge test to determine maximal range of motion (ROM) of the ankle joint. Segment angles of the shank, thigh, and trunk segments as well as ankle joint angles were calculated by 2-dimensional kinematic analysis. Simple linear and multiple regressions were used to test the correlation between the lower extremity angles, segment ratios, and the trunk angle. On average, subjects had an 11.4 ± 4.4° deficit in dorsiflexion ROM between maximal ROM and ROM in the parallel squat (PS) which was independent of maximal ROM. Ankle mobility showed to significantly negatively correlate with trunk angle, thereby showing that a subject with greater ankle ROM had a more upright torso in the PS position. This study was unable to find a significant correlation between the segment ratios and trunk angle. Furthermore, when combined, no significant relationship between ankle mobility, segment length ratios, and trunk angle were found, although it was noticed that this more complex model showed the greatest R value.

The Effects of Footwear on Squat Movements

The purpose of this study was to compare the effects of different footwear (bare feet, flat-soled shoes, and weightlifting shoes) on balance during a barbell back squat in novice and advanced participants. It was hypothesized that i) weightlifting shoes would increase balance performance in the anterior-posterior (AP) and medial-lateral (ML) directions, and ii) advanced participants would demonstrate increased balance performance in the AP and ML direction compared to novice participants. 17 participants (9 novice and 8 advanced) performed 3 trials of a single squat repetition, using a 45lb Olympic standard barbell on a force plate, with bare feet, flat shoes, and weightlifting shoes. Squat 1 and 2 were used as warm-up repetitions and data was collected during squat 3 of each condition. Participants were characterized as either novice or advanced based on the number of training sessions they performed squats each week. Novice participants squatted with a barbell less than once per week, and advanced squatted with a barbell more than once per week. Balance performance was quantified by the percentage of time the centre of pressure (CoP) had the smallest displacement from the average CoP location. A chi-square test was performed to determine the statistically significant changes in CoP displacement between the 3 footwear conditions; accordingly, the post hoc significance interval was calculated to P0.0167). Using a 2-way ANOVA, no significant differences were found between novice and advanced participants’ root mean square values for normalized CoP in the AP or ML directions (P&gt;0.05). Participants during the weightlifting shoe condition were found to have better regulation of balance compared to bare feet or flat shoes conditions. Additionally, it was found that novice and advanced participants did not regulate balance differently from each other during the squat movement.

The Effects of a Heel Wedge on Hip, Pelvis and Trunk Biomechanics During Squatting in Resistance Trained Individuals.

Barbell back squats are a popular exercise for developing lower extremity strength and power. However, this exercise has potential injury risks, particularly to the lumbar spine, pelvis, and hip joint. Previous literature suggests heel wedges as a means of favorably adjusting trunk and pelvis kinematics with the intention of reducing such injury risks. Yet no direct biomechanical research exists to support these recommendations. Therefore, the purpose of this study was to examine the effects of heel wedges compared with barefoot on minimally loaded barbell back squats. Fourteen trained male participants performed a barbell back squat in bare feet or with their feet raised bilaterally with a 2.5-cm wooden block while 3-dimensional kinematics, kinetics, and electromyograms were collected. The heel wedge condition elicited significantly less forward trunk flexion angles at peak knee flexion, and peak external hip joint moments (p ≤ 0.05) compared with barefoot conditions. However, no significant differences were observed between conditions for trunk and pelvis angle differences at peak knee flexion (p > 0.05). Lastly, no peak or root mean square differences in muscle activity were elicited between conditions (p > 0.05). Our results lend support for the suggestions provided in literature aimed at using heel wedges as a means of reducing excessive forward trunk flexion. However, the maintenance of a neutral spine, another important safety factor, is not affected by the use of heel wedges. Therefore, heel wedges may be a viable modification for reduction of excessive forward trunk flexion but not for reduction in relative trunk-pelvis flexion during barbell back squats.

Caffeine ingestion acutely enhances muscular strength and power but not muscular endurance in resistance-trained men

The goal of this randomized, double-blind, cross-over study was to assess the acute effects of caffeine ingestion on muscular strength and power, muscular endurance, rate of perceived exertion (RPE), and pain perception (PP) in resistance-trained men. Seventeen volunteers (mean ± SD: age = 26 ± 6 years, stature = 182 ± 9 cm, body mass = 84 ± 9 kg, resistance training experience = 7 ± 3 years) consumed placebo or 6 mg kg−1 of anhydrous caffeine 1 h before testing. Muscular power was assessed with seated medicine ball throw and vertical jump exercises, muscular strength with one-repetition maximum (1RM) barbell back squat and bench press exercises, and muscular endurance with repetitions of back squat and bench press exercises (load corresponding to 60% of 1RM) to momentary muscular failure. RPE and PP were assessed immediately after the completion of the back squat and bench press exercises. Compared to placebo, caffeine intake enhanced 1RM back squat performance (+2.8%; effect size [ES] = 0.19; p = .016), which was accompanied by a reduced RPE (+7%; ES = 0.53; p = .037), and seated medicine ball throw performance (+4.3%, ES = 0.32; p = .009). Improvements in 1RM bench press were not noted although there were significant (p = .029) decreases in PP related to this exercise when participants ingested caffeine. The results point to an acute benefit of caffeine intake in enhancing lower-body strength, likely due to a decrease in RPE; upper-, but not lower-body power; and no effects on muscular endurance, in resistance-trained men. Individuals competing in events in which strength and power are important performance-related factors may consider taking 6 mg kg−1 of caffeine pre-training/competition for performance enhancement.

Looped Band Placed Around Thighs Increases EMG of Gluteal Muscles Without Hindering Performance During Squatting

**Background:** There is little information about the effects of placing a resistance band around the outer thighs on the amplitude of performance and electromyography (EMG) of lower body muscles during a free barbell back squat (FBBS) activity. This study quantified EMG amplitudes of the gluteus medius, gluteus maximus, vastus lateralis, and biceps femoris dur- ing an FBBS with and without the use of a looped resistance band. In addition, the effects of the looped band on the number of repetitions completed on failure in performing FBBS were measured at 2 intensities. **Methods:** In this study, 15 resistance-trained males (age, 23.6 6 3.5 years) completed an FBBS 3 repetition maximum (RM) test on the first testing day to estimate their 1RM. On days 2 and 3, participants completed 5 repetitions equal to 80% of their estimated 1RM followed by a repetition to failure test using 60% of estimated 1RM with and without a band placed around their thighs in a counter-balanced fashion while EMG amplitudes were collected. **Results:** No differences were found at 60% intensity test between conditions (band: 21.4 6 6, control: 20.4 6 4.7; P = .171). Similarly, no differences were found between conditions in EMG of the vastus lateralis or biceps femoris at both intensities (effect size [ES] range = 0.01–0.4, P ≥ .05). In contrast, other than a few exceptions, gluteus medius and maximus showed greater EMG activity in the looped-band condition during tests (ES range = 0.28– 1.15, P < .05) at both 60% and 80% intensities. **Conclusion:** Placing a looped resistance band around the thighs can be used as a training strategy to increase the activation of the hip muscles during FBBS using medium to heavy loads without negatively affecting performance.

Effects of Zero-Drop Shoes on Knee Joint Kinematics &amp; Kinetics During the Barbell Back Squat

Effects of Zero-Drop Shoes on Knee Joint Kinematics &amp; Kinetics During the Barbell Back Squat

The effects of squatting footwear on three-dimensional lower limb and spine kinetics

Altering footwear worn during performance of the barbell back squat has been shown to change motion patterns, but it is not completely understood how this affects biomechanical loading demands. The primary objective was to compare lower back and extremity net joint moments in 24 experienced weightlifters (12M, 12F) who performed 80% one-repetition maximum back squats under three different footwear conditions (barefoot, running shoes, weightlifting shoes). Results showed that there was a significant main effect of footwear condition on the knee extension moment (p=0.001), where the running and weightlifting shoes produced significantly larger moments than the barefoot condition. There was also a main effect of footwear condition on knee external rotation moments (p=0.002), where the weightlifting shoe produced significantly larger moments than both other conditions. At the hip, there was also a main effect of footwear condition on the extension moment (p=0.004), where the barefoot condition produced significantly larger moments than either the running shoe or weightlifting shoe condition. Lastly, there was also a significant main effect of footwear condition on both hip external (p=0.005) and internal (p=0.003) rotation moments, where the barefoot condition produced greater internal rotation and less external rotation moments than either shod condition. This study indicates that altering footwear conditions while performing the barbell back squat may redistribute the internal biomechanical loading patterns amongst the lower extremity joints and perhaps alter the musculoskeletal adaptations elicited.

Ancient peat and apple extracts supplementation may improve strength and power adaptations in resistance trained men.

BackgroundIncreased cellular ATP levels have the potential to enhance athletic performance. A proprietary blend of ancient peat and apple extracts has been supposed to increase ATP production. Therefore, the purpose of this investigation was to determine the effects of this supplement on athletic performance when used during 12 weeks of supervised, periodized resistance training.MethodsTwenty-five healthy, resistance-trained, male subjects completed this study. Subjects supplemented once daily with either 1 serving (150 mg) of a proprietary blend of ancient peat and apple extract (TRT) or an equal-volume, visually-identical placebo (PLA) daily. Supervised resistance training consisted of 8 weeks of daily undulating periodized training followed by a 2 week overreach and a 2 week taper phase. Strength was determined using 1-repetition-maximum (1RM) testing in the barbell back squat, bench press (BP), and deadlift exercises. Peak power and peak velocity were determined during BP at 30 % 1RM and vertical jump tests as well as a 30s Wingate test, which also provided relative power (watt:mass)ResultsA group x time interaction was present for squat 1RM, deadlift 1RM, and vertical jump peak power and peak velocity. Squat and deadlift 1RM increased in TRT versus PLA from pre to post. Vertical jump peak velocity increased in TRT versus PLA from pre to week 10 as did vertical jump peak power, which also increased from pre to post. Wingate peak power and watt:mass tended to favor TRT.ConclusionsSupplementing with ancient peat and apple extract while participating in periodized resistance training may enhance performance adaptations.Trial RegistrationClinicalTrials.gov registration ID: NCT02819219, retrospectively registered on 6/29/2016

Muscle Group Specific Changes In The Electromechanical Delay Following Short-term Resistance Training

PURPOSE: The time delay between the onset of a muscle’s electrical activity and force is believed to have important functional implications, and has been shown to decrease following resistance training in males. The purpose of this investigation was to examine changes in the voluntary electromechanical delay (EMD) for the leg extensors and flexors following a short-term resistance training intervention in females. METHODS: Twenty-two previously untrained females (mean ± SD age = 21 ± 2 years; mass = 65.4 ± 13.3 kg) were randomly assigned to training (n = 10) and control (n = 12) groups. The training group performed barbell back squats and deadlifts twice per week for four weeks. Each training session was closely supervised, and additional weight was added throughout the study to induce progressive overload. Bipolar surface electromyographic signals and isometric torque-time curves were used to calculate EMD for the vastus lateralis (extensors) and biceps femoris (flexors) during maximal voluntary contractions at both pre- and posttesting. Data were examined using analyses of covariance (ANCOVAs) with the pretest and posttest scores serving as the covariate and dependent variable, respectively, and by evaluating the number of participants that exceeded the minimal difference statistic. RESULTS: For the leg extensors, the adjusted EMD posttest mean for the training group was significantly lower than that for the control group (74.3 vs. 91.8 ms; p = 0.015; ή2 = 0.275), and five training participants displayed decreases that exceeded the minimal difference. The Cohen’s d effect size for the decline in EMD was 0.80. The ANCOVA for the leg flexors was not significant (adjusted means = 98.0 vs. 90.0 ms; p = 0.487; ή2 = .026). CONCLUSIONS: Four weeks of multi-joint resistance training resulted in decreased EMD for the leg extensors, but not the flexors. The lack of a decrease in leg flexor EMD may have been related to training specificity, biarticular muscle function, and/or an insufficient training stimulus.

Influence of Footwear Type on Barbell Back Squat Using 50, 70, and 90% of One Repetition Maximum: A Biomechanical Analysis.

The effect of footwear type was investigated during the barbell back squat using three-dimensional motion analysis and ground reaction force data. Nine male participants (mean age = 26.4 ± 5.4 years, height = 1.79 ± 0.08 m, and mass = 84.7 ± 16.1 kg) completed 2 experimental testing sessions wearing 2 different forms of training footwear: (a) standard sports trainers (running shoes [RS]) and (b) specialized weightlifting shoes (WS). On each test day, participants completed a sequence of 5, 3, and 1 repetitions of a barbell back squat using 50, 70, and 90%, respectively, of their 1 repetition maximum (1RM) load in each of the shoe conditions. Shoe order, which was initially randomly assigned for test day 1, was reversed on test day 2. Significant main effects were found for peak dorsiflexion of both left (p < 0.001) and right (p < 0.001) ankles. Pairwise post hoc comparisons showed that the RS condition exhibited significantly more dorsiflexion compared with the WS condition in both left and right ankles. There was also a significant main effect of load (%1RM) within the left ankle (p < 0.01) with post hoc comparisons showing that there was a significant increase in peak dorsiflexion angle from 50 to 90% (p ≤ 0.05) and 70-90% of 1RM (p ≤ 0.05) but no difference between 50 and 70% of 1RM (p = 1.000). These findings indicate that further investigation is necessary to substantiate claims regarding the benefits of wearing WS during resistance training exercises targeting the squat movement.

Effects of Five-Week Resistance Training in Hypoxia on Hormones and Muscle Strength.

The effects of different levels of systemic hypoxia on hormonal responses, strength, and body composition to 5-week resistance training were investigated. Twenty-five male subjects were randomly assigned into 3 experimental groups that performed 10 sessions (2 sessions per week) of barbell back squat (10 repetitions, 5 sets, 70% 1 repetition maximum [RM]) under normoxia (NR, FiO2 = 21%) and hypoxia (HL, FiO2 = 16%; HH, FiO2 = 12.6%). Serum growth hormone (GH), testosterone (T), and cortisol (C) concentrations were measured before (Pre) and at 0 (T-0), 15 (T-15), 30 (T-30) minutes after exercise in the first and last training sessions. One repetition maximum, isometric knee extension, isometric leg press (LP), and body composition were evaluated before and after the protocol. In the first session, GH of HH (p < 0.01) and HL (p < 0.01) was higher than NR at T-0. In the last session, only GH of HH was higher than NR at T-0 (p ≤ 0.05); meanwhile, T/C ratio of HH was higher than NR at Pre (p < 0.01), T-0 (p < 0.01), and T-15 (p ≤ 0.05). Following the training protocol, HH showed greater (p ≤ 0.05) improvement of isometric LP strength compared with NR; lean body mass was increased in the hypoxia groups only. Moderate-intensity resistance training performed in severe hypoxia (FiO2 = 12.6%) induced greater GH responses and isometric strength gains in LP than that in NR. FiO2 of 12.6% was recommended when performing the moderate-intensity resistance training under systemic hypoxia.

Muscle group specific changes in the electromechanical delay following short-term resistance training.

The time delay between the onset of a muscle's electrical activity and force is believed to have important functional implications, and has been shown to decrease following resistance training in males. The purpose of this investigation was to examine changes in the voluntary electromechanical delay (EMD) for the leg extensors and flexors following a short-term resistance training intervention in females. Pretest/posttest control group experiment. Twenty-two previously untrained females (mean±SD age=21±2 years; mass=65.4±13.3kg) were randomly assigned to training (n=10) and control (n=12) groups. The training group performed barbell back squats and deadlifts twice per week for four weeks. EMD for the vastus lateralis (extensors) and biceps femoris (flexors) was examined during maximal voluntary contractions at pre- and posttesting. Data were examined using analyses of covariance (ANCOVAs) with the pretest and posttest scores serving as the covariate and dependent variable, respectively, and by evaluating the number of participants that exceeded the minimal difference statistic. For the leg extensors, the adjusted EMD posttest mean for the training group was significantly lower than that for the control group (74.3 vs. 91.8ms; p=0.015; ή(2)=0.275), and five training participants displayed decreases that exceeded the minimal difference. The ANCOVA for the leg flexors was not significant (adjusted means=98.0 vs. 90.0ms; p=0.487; ή(2)=.026). Four weeks of multi-joint resistance training resulted in decreased EMD for the leg extensors, but not the flexors.

Effects of sub-chronic branched chain amino acid supplementation on markers of muscle damage and performance variables following 1 week of rigorous weight training

Methods Apparently healthy resistance trained males (n = 30) were randomized to either a BCAA group or the CHO control group. Participants performed preliminary testing (T1) to derive peak quadriceps isometric torque, peak quadriceps isokinetic torque (60o and 120o per second), and a 1RM barbell back squat. The following week, the participants performed 10x5 repetitions at 80% of their 1RM barbell back squat for 3 consecutive days. During this experimental intervention antecubital blood was drawn to assess serum myoglobin concentrations, in addition a visual analog scale was utilized in order to measure subjective perceptions of muscular soreness. 48 hours following the third bout of exercise, participants performed post testing (T2) like T1 testing and donated a final blood draw.

Comparison of muscle activation of hip belt squat and barbell back squat techniques

BACKGROUND: Hip belt squats are believed to have been introduced in 1970. By removing the load from the shoulders and upper trapezius, the hip belt squat places emphasis on the legs with less load on the spine. No peer-reviewed research exists on the muscle recruitment patterns of a hip belt squat, or how it compares in muscle activation to other squatting activities. OBJECTIVE: The purpose of the study was to determine lower extremity muscle activation in a hip belt squat (SquatMax = MD) in comparison with a barbell back squat. METHODS: Thirteen participants performed four repetitions of an 8-RM squat using three different techniques: hip belt squat without a band, hip belt squat with a band, and barbell back squat. Electromyographic data were collected from six muscles: quadriceps, biceps femoris, hip adductors, hip abductors, gluteus maximus, and gastrocnemius. RESULTS: ANOVA revealed no significant difference in muscle activity between devices. The only muscle group statistically different between genders was the gastrocnemius (p = 0.04). Hip adductor activity was lowest and hip abductor activity was highest when performing a hip belt squat with the band for both genders. Likewise, the adductor to hamstring ratio was lowest with the hip belt squat. CONCLUSIONS: Given the lack of significant difference in the muscle activity between the squat techniques, one needs to look at other attributes to determine both the scientific and, consequently, the practical value. Given the placement of the belt around the pelvis, one positive attribute for the hip belt squat is the ability to unload the shoulders and spine. Another positive attribute for the hip belt squat is the higher hip abductor to adductor ratio. This could be very important for injury prevention and patella tracking. While the back squat has slightly higher hamstring recruitment, which is important in ACL injury prevention, the hip belt squat may address this by offsetting the free weight with the use of an additional band. If a free weight hip belt squat device is available, it may be a better alternative to the traditional barbell squat technique.