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Back Squat

Daniel J Southwell, Shane A Petersen, Tyson A C Beach, Ryan B Graham
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...
October 12, 2016: Journal of Electromyography and Kinesiology
Clare F Heisey, J Derek Kingsley
Static stretching was once recognized as a method of preparation for physical activity that would inhibit performance and increase risk of injury. However, a growing body of research suggests that static stretching may not have an inhibitory effect. Regardless, the data have not examined gender differences or the fatigue index (FI) and flexibility effects of static stretching on the back squat over multiple sets. Therefore, the purpose of this study was to examine the relationship between a static-stretch condition (SC) and control condition (CC) on flexibility and the FI of Division I female athletes during 4 sets of the back squat...
2016: International Journal of Exercise Science
Kyle T Aune, Joseph M Powers
BACKGROUND: Extreme conditioning programs (ECPs) are fitness training regimens relying on aerobic, plyometric, and resistance training exercises, often with high levels of intensity for a short duration of time. These programs have grown rapidly in popularity in recent years, but science describing the safety profile of these programs is lacking. HYPOTHESIS: The rate of injury in the extreme conditioning program is greater than the injury rate of weightlifting and the majority of injuries occur to the shoulder and back...
October 19, 2016: Sports Health
Fabrício E Rossi, Brad J Schoenfeld, Skyler Ocetnik, Jonathan Young, Andrew Vigotsky, Bret Contreras, James W Krieger, Michael G Miller, Jason Cholewa
BACKGROUND: The purpose of this study was to compare strength, body composition, and functional outcome measures following performance of the back squat, leg press, or a combination of the two exercises. METHODS: Subjects were pair-matched based on initial strength levels and then randomly assigned to 1 of 3 groups: A squat-only group (SQ) that solely performed squats for the lower body; a leg press-only group (LP) that solely performed leg presses for the lower body, or; a combined squat and leg press group (SQ-LP) that performed both squats and leg presses for the lower body...
October 13, 2016: Journal of Sports Medicine and Physical Fitness
Paige E Rice, Courtney L Goodman, Christopher R Capps, N Travis Triplett, Travis M Erickson, Jeffrey M McBride
The purpose of this study was to compare force- and power-time curve variables during jumping between Division I strength-matched male and female basketball athletes. Males (n = 8) and females (n = 8) were strength matched by testing a one-repetition maximum (1RM) back squat. 1RM back squat values were normalised to body mass in order to demonstrate that strength differences were a function of body mass alone. Subjects performed three countermovement jumps (CMJ) at maximal effort. Absolute and relative force- and power-time curve variables from the CMJs were analysed between males and females...
October 1, 2016: European Journal of Sport Science
J M Oliver, S C Jenke, J D Mata, A Kreutzer, M T Jones
This study compared the acute cytokine response, and kinetic and kinematic profile following back squat exercise in resistance-trained men. In a randomized, cross-over design, 10 resistance-trained men (27±4 y, 1.80±0.07 m, 82.8±6.7 kg, 16.3±3.5% fat) performed the back squat exercise using traditional and cluster set configurations. Kinetic and kinematic data were sampled throughout each condition. Venous blood was sampled prior, immediately post, 30 min, 60 min, 24 h, and 48 h post-exercise for plasma interleukin-6 (IL-6) and interleukin-15 (IL-15)...
September 27, 2016: International Journal of Sports Medicine
Harry G Banyard, Kazunori Nosaka, G Gregory Haff
This study investigated the reliability and validity of the load-velocity relationship to predict the free-weight back squat 1RM. Seventeen strength-trained males performed three 1RM assessments on three separate days. All repetitions were performed to full depth with maximal concentric effort. Predicted 1RMs were calculated by entering the mean concentric velocity of the 1RM (V1RM) into an individualized linear regression equation, which was derived from the load-velocity relationship of three (20, 40, 60% of 1RM), four (20, 40, 60, 80% of 1RM), or five (20, 40, 60, 80, 90% of 1RM) incremental warm-up sets...
September 21, 2016: Journal of Strength and Conditioning Research
Jesse M Charlton Bpec Cscs, Connor A Hammond, Christopher K Cochrane, Gillian L Hatfield, Michael A Hunt
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 favourably 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 to barefoot on minimally loaded barbell back squats...
September 20, 2016: Journal of Strength and Conditioning Research
Jonathan M Oliver, Anthony L Almada, Leighsa E Van Eck, Meena Shah, Joel B Mitchell, Margaret T Jones, Andrew R Jagim, David S Rowlands
Athletes in sports demanding repeat maximal work outputs frequently train concurrently utilizing sequential bouts of intense endurance and resistance training sessions. On a daily basis, maximal work within subsequent bouts may be limited by muscle glycogen availability. Recently, the ingestion of a unique high molecular weight (HMW) carbohydrate was found to increase glycogen re-synthesis rate and enhance work output during subsequent endurance exercise, relative to low molecular weight (LMW) carbohydrate ingestion...
2016: PloS One
Ram Haddas, Steven F Sawyer, Phillip S Sizer, Toby Brooks, Ming-Chien Chyu, C Roger James
INTRODUCTION: Recurrent LBP (rLBP) and neuromuscular fatigue are independently thought to increase the risk of lower extremity (LE) injury. Volitional preemptive abdominal contraction (VPAC) is thought to improve lumbar spine and pelvis control in individuals with rLBP. The effects of VPAC on fatigued landing performance in individuals with rLBP are unknown. OBJECTIVES: To determine the effects of VPAC and LE fatigue on landing performance in a rLBP population. DESIGN: Cross-sectional pretest-posttest cohort control design...
August 24, 2016: Journal of Sport Rehabilitation
Jacob E Earp, Robert U Newton, Prue Cormie, Anthony J Blazevich
INTRODUCTION: Tendon dynamics influence movement performance and provide the stimulus for long-term tendon adaptation. As tendon strain increases with load magnitude and decreases with loading rate, changes in movement speed during exercise should influence tendon strain. METHODS: Ten resistance-trained men [squat one repetition maximum (1RM) to body mass ratio: 1.65 ± 0.12] performed parallel-depth back squat lifts with 60% of 1RM load at three different speeds: slow fixed-tempo (TS: 2-s eccentric, 1-s pause, 2-s concentric), volitional-speed without a pause (VS) and maximum-speed jump (JS)...
2016: Frontiers in Physiology
James J Tufano, Jenny A Conlon, Sophia Nimphius, Lee E Brown, Harry G Banyard, Bryce D Williamson, Leslie G Bishop, Amanda J Hopper, G Gregory Haff
PURPOSE: The purpose of this study was to determine the effects of intra-set rest frequency and training load on muscle time under tension, external work, and external mechanical power output during back squat protocols with similar changes in velocity. METHODS: Twelve strength-trained men (26.0±4.2 y; 83.1±8.8 kg; 1.75±0.06 m; 1.88 ± 0.19 1RM:body mass) performed three sets of twelve back squats using three different set structures: traditional sets with 60% 1RM (TS), cluster sets of four with 75% 1RM (CS4), and cluster sets of two with 80% 1RM (CS2)...
September 6, 2016: International Journal of Sports Physiology and Performance
J L Ayers, M DeBeliso, T G Sevene, K J Adams
Olympic weightlifting movements and their variations are believed to be among the most effective ways to improve power, strength, and speed in athletes. This study investigated the effects of two Olympic weightlifting variations (hang cleans and hang snatches), on power (vertical jump height), strength (1RM back squat), and speed (40-yard sprint) in female collegiate athletes. 23 NCAA Division I female athletes were randomly assigned to either a hang clean group or hang snatch group. Athletes participated in two workout sessions a week for six weeks, performing either hang cleans or hang snatches for five sets of three repetitions with a load of 80-85% 1RM, concurrent with their existing, season-specific, resistance training program...
September 2016: Biology of Sport
Jeremy R Townsend, Jeffrey R Stout, Adam R Jajtner, David D Church, Kyle S Beyer, Leonardo P Oliveira, Michael B La Monica, Joshua J Riffe, Tyler W D Muddle, Kayla M Baker, David H Fukuda, Michael D Roberts, Jay R Hoffman
PURPOSE: The NF-κB signaling pathway regulates multiple cellular processes following exercise stress. This study aims to examine the effects of an acute lower-body resistance exercise protocol and subsequent recovery on intramuscular NF-κB signaling. METHODS: Twenty-eight untrained males were assigned to either a control (CON; n = 11) or exercise group (EX; n = 17) and completed a lower-body resistance exercise protocol consisting of the back squat, leg press, and leg extension exercises...
August 31, 2016: European Journal of Applied Physiology
(no author information available yet)
A number of studies have established that higher levels of strength and power, tested at the end of the pre-season, distinguish between playing level in professional rugby league. How this may impact the ability of players to get selected for final pay-off games some 30-wks later has not been fully investigated. The purpose of this study was to compare measures of upper and lower body strength between players from the same professional club, designated as those seventeen players who attained selection and played in the team that won the Grand Final of the National Rugby League (NRL) competition (GF) and those who did not attain selection (NSGF)...
August 18, 2016: Journal of Strength and Conditioning Research
Min-Joo Ko, Kyung-Hee Noh, Min-Hyeok Kang, Jae-Seop Oh
[Purpose] Differences in scores on the Functional Movement Screen between patients with chronic lower back pain and healthy control subjects were investigated. [Subjects and Methods] In all, 20 chronic lower back pain patients and 20 healthy control subjects were recruited. Chronic lower back pain patients and healthy controls performed the Functional Movement Screen (deep squat, hurdle step, inline lunge, shoulder mobility, active straight leg raise, trunk stability pushup, and rotary stability). The Mann-Whitney test was used to analyze differences in Functional Movement Screen scores between the two groups...
July 2016: Journal of Physical Therapy Science
Paulo Henrique Marchetti, Josinaldo Jarbas da Silva, Brad Jon Schoenfeld, Priscyla Silva Monteiro Nardi, Silvio Luis Pecoraro, Julia Maria D'Andréa Greve, Erin Hartigan
The purpose of this study was to compare muscle activation of the lower limb muscles when performing a maximal isometric back squat exercise over three different positions. Fifteen young, healthy, resistance-trained men performed an isometric back squat at three knee joint angles (20°, 90°, and 140°) in a randomized, counterbalanced fashion. Surface electromyography was used to measure muscle activation of the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), and gluteus maximus (GM)...
2016: Journal of Sports Medicine (Hindawi Publishing Corporation)
Wesley C Kephart, Petey W Mumford, Anna E McCloskey, A Maleah Holland, Joshua J Shake, C Brooks Mobley, Adam E Jagodinsky, Wendi H Weimar, Gretchen D Oliver, Kaelin C Young, Jordan R Moon, Michael D Roberts
BACKGROUND: Amino acid supplementation has been shown to potentially reduced exercise-induced muscle soreness. Thus, the purpose of this study was to examine if branched chain amino acid and carbohydrate (BCAACHO) versus carbohydrate-only sports drink (CHO) supplementation attenuated markers of muscle damage while preserving performance markers following 3 days of intense weight training. METHODS: Healthy resistance-trained males (n = 30) performed preliminary testing (T1) whereby they: 1) donated a baseline blood draw, 2) performed knee extensor dynamometry to obtain peak quadriceps isometric and isokinetic torque as well as electromyography (EMG) activity at 60°/s and 120°/s, and 3) performed a one repetition maximum (1RM) barbell back squat...
2016: Journal of the International Society of Sports Nutrition
Ning Jia, Tao Li, Shuangqiu Hu, Xinhe Zhu, Kang Sun, Long Yi, Qiong Zhang, Guilian Luo, Yuzhen Li, Xueyan Zhang, Yongen Gu, Zhongxu Wang
BACKGROUND: With the increasingly severe energy shortage and climate change problems, developing wind power has become a key energy development strategy and an inevitable choice to protect the ecological environment worldwide. The purpose of this study was to investigate the prevalence of low back pain (LBP) and analyze its risk factors among operation and maintenance personnel in wind farms (OMPWF). METHODS: A cross-sectional survey of 151 OMPWF was performed, and a comprehensive questionnaire, which was modified and combined from Nordic Musculoskeletal Questionnaires (NMQ), Washington State Ergonomics Tool (WSET) and Syndrome Checklist-90(SCL-90) was used to assess the prevalence and risk factors of LBP among OMPWF...
2016: BMC Musculoskeletal Disorders
Ramires A Tibana, Leonardo M de Almeida, Nuno M Frade de Sousa, Dahan da Cunha Nascimento, Ivo V de Sousa Neto, Jeeser A de Almeida, Vinicius C de Souza, Maria de Fátima T P L Lopes, Otávio de Tolêdo Nobrega, Denis C L Vieira, James W Navalta, Jonato Prestes
The aim of this study was to investigate the effects of two consecutive Crossfit® training sessions (24 h apart) designed to enhance work-capacity that involved both cardiovascular and muscular exercises on cytokines, muscle power, blood lactate and glucose. Nine male members of the CrossFit® community (age 26.7 ± 6.6 years; body mass 78.8 ± 13.2 kg; body fat 13.5 ± 6.2%; training experience 2.5 ± 1.2 years) completed two experimental protocols (24 h apart): (1) strength and power exercises, (2) gymnastic movements, and (3) metabolic conditioning as follows: 10 min of as many rounds as possible (AMRAP) of 30 double-unders and 15 power snatches (34 kg)...
2016: Frontiers in Physiology
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