The back squat is an integral aspect of any resistance training program to improve athletic performance. It is also used for injury prevention of the lower limbs.
OBJECTIVE:
The purpose of this study was to examine the effect of back squat training at different intensities on strength and flexibility of the hamstring muscle group (HMG).
METHODS:
Twenty-two male recreational bodybuilders with at least two years of experience in resistance training were recruited to participate in a nine-week training program. They were randomly assigned to a heavy back squat group (90-95% of one repetition maximum) or a moderate-intensity back squat group (60-65% of one repetition maximum).
RESULTS:
The heavy back squat group resulted in a significantly (p < 0.001) increased in one repetition maximum strength but a significant (p < 0.001) reduction in HMG flexibility when compared to their counterparts. The results of the study indicate that while a heavy back squat training program is effective in improving strength, it has an adverse effect on the flexibility of the HMG.
CONCLUSION:
The implication of this study is that there is a tradeoff between strength and flexibility and trainers should select the appropriate training protocols for their athletes to maximize athletic performance.
ShawBS, ShawI, BrownGA. Comparison of resistance and concurrent resistance and endurance training regimes in the development of strength. J Strength Cond Res2009; 23(9): 2507-14.
2.
BuschAJ, WebberSC, RichardsRS, BidondeJ, SchachterCL, SchaferLA, DanyliwA, SawantA, Dal Bello-HaasV, RaderT, OverrendTJ. Resistance exercise training for fibromyalgia2013; 20(12): CD010884.
3.
ChristouM, SmiliosI, SotiropoulosK, VolaklisK, PilianidisT, TokmakidisSP. Effects of resistance training on the physical capacities of adolescent soccer players. J Strength Cond Res2006; 20(4): 783-91.
4.
Van MiddelkoopM, RubinsteinSM, KuijpersT, VerhagenAP, OsteloR, KoesBW, van TulderMW. A systematic review on the effectiveness of physical and rehabilitation interventions for chronic non-specific low back pain. Eur Spine J2011; 20(1): 19-39.
5.
SmithD, BissellG, Bruce-LowS, WakefieldC. The effect of lumbar extension training with and without pelvic stabilization on lumbar strength and low back pain. J Back Musculoskelet Rehabil2011; 24(4): 241-9.
6.
SilderA, ThelenDG, HeiderscheitBC. Effects of prior hamstring strain injury on strength, flexibility, and running mechanics. Clin Biomech2010; 25(7): 681-6.
7.
SantosE, RheaMR, SimãoR, DiasI, de SallesBF, NovaesJ, LeiteT, BlairJC, BunkerDJ. Influence of moderately intense strength training on flexibility in sedentary young women. J Strength Cond Res2010; 24(11): 3144-9.
8.
SairyoK, KawamuraT, MaseY, HadaY, SakaiT, HasebeK, DezawaA. Jack-knife stretching promotes flexibility of tight hamstrings after 4 weeks: A pilot study. Eur J Orthop Surg Traumatol2013; 23: 657-63.
9.
GorsuchJ, LongJ, MillerK, PrimeauK, RutledgeS, SossongA, DurocherJJ. The effect of squat depth on multiarticular muscle activation in collegiate cross-country runners. J Strength Cond Res2013; 27(9): 2619-25.
10.
HooperDR, SzivakTK, ComstockBA, Dunn-LewisC, ApicellaJM, KellyNA, CreightonBC, FlanaganSD, LooneyDP, VolekJS. Effects of Fatigue from resistance training on barbell back squat biomechanics. J Strength Cond Res2014; 28(6): 1127-34.
11.
EbbenWP, LeighDH, JensenRL. The role of the back squat as a hamstring training stimulus. Strength Cond J2000; 22(15): 147-54.
12.
SaraivaAR, ReisVM, CostaPB, BentesCM, Costa e SilvaGV, NovaesJS. Chronic effects of different resistance training exercise orders on flexibility in elite judo athletes. J Hum Kinet2014; 40(1): 129-37.
13.
EkstrandJ, GillquistJ. The frequency of muscle tightness and injuries in soccer players. Am J Sports Med1981; 10(2): 75-8.
14.
MendiguchiaJ, Alentorn-GeliE, BrughelliM. Hamstring strain injuries: Are we heading in the right direction? Br J Sports Med2012; 46: 81-5.
15.
OparMDA, WilliamsMD, ShieldAJ. Hamstring strain injuries. Sport Med2012; 42(3): 209-26.
16.
Iashvili,AV. Active and passive flexibility in athletes specializing in different sports. Soviet Sports Review1983; 18: 30-2.
17.
AguilarAJ, DiStefanoLJ, BrownCN, HermanDC, GuskiewiczKM, PaduaDA. A dynamic warm-up model increases quadriceps strength and hamstring flexibility. J Strength Cond Res2012; 26(7): 1130-41.
18.
BacurauRFP, MonteiroGA, UgrinowitschC, TricoliV, CabralLF, AokiMS. Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength. J Strength Cond Res2009; 23(1): 304-8.
19.
BatistaMAB, RoschelH, BarrosoR, UgrinowitschC, TricoliV. Influence of strength training background on postactivation potentiation response. J Strength Cond Res2011; 25(5): 2496-502.
20.
ShariatA, KargarfardM, Mohd TamrinSB, DanaeeM, KarimiH. Strength-training and biological rhythm of male sex hormone among judoists. Biol Rhythm Res2014; 45(4): 1-14.
21.
ShariatA, KargarfardM, SharifiGR. The effect of heavy resistance exercise on circadian rhythm of salivary cortisol in male body building athletes. J Isfahan Med Sch2012; 29(3): 2400-12.
22.
KraemerWJ, NicholasAR. Hormonal responses and adaptations to resistance exercise and training. Sports medicine2005; 35(4): 339-61.
23.
Ritti-DiasRM, AvelarA, SalvadorEP, CyrinoES. Influence of previous experience on resistance training on reliability of one-repetition maximum test. J Strength Cond Res2011; 25(5): 1418-22.
24.
ShariatA, KargarfardM, DanaeeM, Bahri Mohd TamrinS. Intensive resistance exercise and circadian salivary testosterone concentrations among young male recreational lifters. J Strength Cond Res2015; 29(1): 151-8.
25.
AyalaF, Sainz de BarandaP, De Ste CroixM, SantonjaF. Absolute reliability of five clinical tests for assessing hamstring flexibility in professional futsal players. J Sci Med Sport2012; 15(2): 142-7.
26.
BaltaciG, UnN, TunayV, BeslerA, GerçekerS. Comparison of three different sit and reach tests for measurement of hamstring flexibility in female university students. Br J Sports Med2003; 37(1): 59-61.
27.
ChanSP, HongY, RobinsonPD. Flexibility and passive resistance of the hamstrings of young adults using two different static stretching protocols. Scand J Med Sci Sports2001; 11(2): 81-6.
28.
JacksonA, LangfordNJ. The criterion-related validity of the sit and reach test: replication and extension of previous findings. Res Q Exerc Sport1989; 60(4): 384-7.
29.
JacksonAW, BakerAA. The relationship of the sit and reach test to criterion measures of hamstring and back flexibility in young females. Res Q Exerc Sport1986; 57(3): 183-6.
30.
MortonSK, WhiteheadJR, BrinkertRH, CaineDJ. Resistance training vs. static stretching: effects on flexibility and strength. J Strength Cond Res2011; 25(12): 3391-8.
31.
NoóbregaA, PaulaK, CarvalhoA. Interaction between resistance training and flexibility training in healthy young adults. J Strength Cond Res2005; 19(4): 842-6.
32.
JacksonJK, ShepherdTR, KellRT. The influence of periodized resistance training on recreationally active males with chronic nonspecific low back pain. J Strength Cond Res2011; 25(1): 242-51.
33.
FatourosIG, KambasA, KatrabasasI, LeontsiniD, ChatzinikolaouA, JamurtasAZ, DouroudosI, AggelousisN, TaxildarisK. Resistance training and detraining effects on flexibility performance in the elderly are intensity-dependent. J Strength Cond Res2006; 20(3): 634-42.
34.
BarrettC, SmerdelyP. A comparison of community-based resistance exercise and flexibility exercise for seniors. Aust J Physiother2002; 48(3): 215-9.
35.
IsearJA, Jr, EricksonJC, WorrellTW. EMG analysis of lower extremity muscle recruitment patterns during an unloaded squat. Med Sci Sports Exerc1997; 29(3): 532-9.
36.
HunterGR, McCarthyJP, BryanDR, ZuckermanPA, BammanMM, ByrneNM. Increased strength and decreased flexibility are related to reduced oxygen cost of walking. Eur J Appl Physiol2008; 104(5): 895-901.
37.
GiessingJ, EichmannB, SteeleJ, FisherJ. A comparison of low volume ``high-intensity-training' and high volume traditional resistance training methods on muscular performance, body composition, and subjective assessments of training. Biol Sport2016; 33(3): 241-9.
38.
WillisLH, SlentzCA, BatemanLA, ShieldsAT, PinerLW, BalesCW, HoumardJA, KrausWE. Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults. J Appl Physiol2012; 113(12): 1831-7.
39.
RossowLM, FukudaDH, FahsCA, LoennekeJP, StoutJR. Natural bodybuilding competition preparation and recovery: A 12-month case study. Int J Sports Physiol Perform2013; 8: 582-92.
40.
BushJ. Hurdles: Technique and training. 1984 US Olympic Trials Clinic. University of South. Los Angeles, CA. 1984.
41.
GambettaV, HillD. Hurdling. In GambettaV. (Ed.): Track and field coaching manual (pp. 72-8). West Point, NY. 1981.
42.
PereversjovE, TabatchnikB, ChalilovV. Zur Erfasung von Talenten im Hiirdenlauf. DLV-Lehrbeilage1984; 110: 15-22.
