Article

Chronic Stretching and Voluntary Muscle Force

April 2008
The Journal of Strength and Conditioning Research 22(2):589-96

Source
PubMed

Authors:

University of New Hampshire

The purpose of the study was to determine whether muscle force, power, and optimal length were affected by 4 weeks of static or ballistic stretching. Twenty-nine males (age, 18-60 years) performed 4 maximal hip extensions to measure peak torque (PT), rate of torque development (RTD), work (W), and PT angle (PTA). Then, participants completed 4 weeks of static or ballistic flexibility training of the hip extensors followed by repetition of the testing protocol. After training, PT increased 5.3 +/- 19.0% in the static group (SG), 7.8 +/- 12.7% in the ballistic group (BG), and 6.1 +/- 17.9% in the control group (CG). RTD increased 4.8 +/- 22.7% in the SG, 3.6 +/- 28.0% in the BG and 9.7 +/- 24.0% in the CG. W increased 3.9 +/- 7.0% in the SG, 14.7 +/- 27.4% in the BG, and 5.5 +/- 9.5% in the CG. PTA changed little with a -1.6 +/- 6.6% decrease in the SG and increases of 0.86 +/- 4.1% in the BG and 0.18 +/- 8.7% in the CG. None of the results were statistically different between stretching group and CG (alpha = 0.05). These data suggest that 4 weeks of stretching have little effect on muscle strength, power, W, or length-tension relationship. PTA changed little, suggesting that a lengthening of the muscle with stretching did not occur. It is suggested that individuals can routinely stretch following exercise to maintain flexibility but should avoid stretching prior to exercise requiring high levels of muscle force. Before exercise that requires high muscular forces, individuals may perform dynamic, sport-specific exercises to increase blood flow, metabolic activity, temperature, and compliance of the muscle.

Effects of 6-Week Static Stretching of Knee Extensors on Flexibility, Muscle Strength, Jump Performance, and Muscle Endurance

Article

Aug 2018

Ikeda, N and Ryushi, T. Effects of 6-week static stretching of knee extensors on flexibility, muscle strength, jump performance, and muscle endurance. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was to evaluate the changes in flexibility and muscular performance after stretching training for 6 weeks. Twelve healthy young men were assigned to a stretching group and 13 to a control group. The participants of the stretching group performed static stretching of knee extensors for 6 weeks. Knee flexion range of motion (KFROM), leg extension strength, rate of force development (RFD) in leg extension, jump performance (squat and countermovement jump height, and index of rebound jump), and strength decrement index of 50 repetitions of isokinetic knee extension (muscle endurance) were measured before and after the interventions. In the stretching group, KFROM significantly increased from 145.2 ± 17.3 to 158.7 ± 6.3° (p < 0.05), whereas RFD significantly improved from 10,173 ± 2,401 to 11,883 ± 2,494 N·s (p < 0.05). By contrast, leg extension strength and jump performance of each jump type did not improve significantly. Furthermore, muscle endurance decreased significantly. All variables remained unchanged in the control group. In conclusion, 6 weeks of stretching training of knee extensors improved KFROM and RFD in leg extension, but not leg extension strength and jump performance; moreover, muscle endurance decreased. These findings indicate that this stretching training protocol can be used by athletes in sports who require high flexibility and those who require high-power exertion.

An Examination of Pre-Activity and Post-Activity Stretching Practices of NCAA Division I and NCAA Divison III Basketball Programs

Article

Apr 2011

The purpose of this study was to determine if NCAA Division I and III men’s basketball programs were in compliance with recommended pre- and post-activity stretching protocols. Questionnaires were sent to 500 NCAA Division I and Division III programs in the United States. Seventy-six coaches (75 males & 1 female) participated in the study. Chi-Square analysis (χ ² (3,n=69) = 42.29, p≤0.001) indicated a greater combined percentage of static/pnf/ballistic stretches (10.14%, n=7) and combination of stretches (57.97%, n=40) than expected as compared to dynamic stretches (31.89%, n=22). Participants were asked during what period (pre- or post-activity) stretching should be emphasized. The results were significantly different from expected (χ ² (4,n=76) = 129.28, p≤0.001), with a greater percentage of pre-activity stretches (26.31%, n=20) and both pre- and post-activity of stretches (60.52%, n=46) being reported as compared to post-activity stretches (13.15%, n=10). Some results seemed to be in conflict with current recommendations in the literature regarding pre-activity stretching practices.

Pre- and Post-Activity Activity Stretching Practices of Collegiate Athletic Trainers in the United States.

Article

Feb 2015

The aim of the study was to investigate the knowledge and practices of collegiate-certified athletic trainers (ATs) in the United States. Participants (n= 521) were provided an overview of the study, as well as a hyperlink to a web-based survey. The "Pre- and Post-Activity Practices in Athletic Training Questionnaire" consisted of demographic items and elements to measure knowledge and practices related to pre- and post-activity stretching routines. In previous studies, the survey demonstrated construct validity, α = .722. Pearson chi-square test was used to evaluate goodness of fit, and kappa was calculated to measure agreement between items. Only 32.2% of ATs recommended dynamic stretching (DS) to be performed pre-activity, whereas a larger percentage (42.2%) recommended a combination of static stretching (SS) and DS. ATs reported that only 28.0% of athletes are performing DS prior to activity. Conversely, 60.6% of collegiate ATs recommended SS post-exercise, and 61.0% of athletes agree and perform post-workout static stretching (κ=0.761, P<0.001). Collegiate ATs appear to under-utilize the current research evidence, which indicates that DS is more beneficial than SS when used pre-activity, and ATs continue to regularly incorporate SS in their pre-activity routines. However, there is evidence that collegiate ATs in the United States emphasize SS post-activity in a manner consistent with current research.

Pre-Activity and Post-Activity Stretching Perceptions and Practices in NCAA Division I Volleyball Programs.

Article

Full-text available

Jan 2010

The purpose of this study was to determine if NCAA Division I women's volleyball programs were in compliance with suggested current pre-and post-activity stretching protocols. Questionnaires were sent to NCAA division I women's volleyball programs in the United States. Fifty six coaches (23 males & 33 females) participated in the study. Some results seemed to conflict with current suggested practices for pre-activity stretching. The results of this study indicate that certification may not influence how well research guidelines are followed. Further research is needed to delineate how these factors affect coaching decisions.

Pre-and Post-Activity Stretching Protocols of NCAA American Football Programs: Influence of Certification and Division Affiliation

Article

Full-text available

Jun 2014

The purpose of this study was to analyze the pre- and post-activity stretching practices of NCAA Division I FBS, II, and III football programs in the United States to determine whether stretching practices are influenced by divisional status and certification. A 31-item survey instrument was developed and used to collect data from 104 coaches ranging in age from 24 to 67 years (M = 42.59, SD =9.47). The results of the Pearson's Chi Square analysis demonstrated significant differences in the answers to three questions of interest based upon the CSCS certification status of the individual. Kruskal-Wallis analysis revealed the length of the pre-activity flexibility is influenced by divisional level (χ² = 6.276, p = 0.043). The results of this study indicate that divisional status and certification may influence how well research guidelines are followed. Further research is needed to delineate how these factors affect coaching decisions.

INFLUÊNCIA DO TREINAMENTO CRÔNICO DE FLEXIBILIDADE SOBRE AS VARIÁVEIS ISOCINÉTICAS: UM ENSAIO CLÍNICO RANDOMIZADO

Article

Full-text available

Mar 2024

Nos últimos anos, muitos estudos foram realizados com o intuito de comprovar a eficácia de protocolos de alongamentos agudos sobre as habilidadesmotoras de força e potência muscular, no entanto seus efeitos crônicos ainda não foram totalmente elucidados na literatura. O objetivo do presente estudo foiverificar a influência de um protocolo de alongamento ativo estático crônico dos músculos quadríceps e isquiostibiais sobre a flexibilidade e as variáveis isocinéticasde força e potência em adultos praticantes de musculação, durante 12 semanas. Trata-se de um ensaio clínico randomizado (parecer número: 2.697.277), no qual aamostra foi composta por 20 adultos do sexo masculino, praticantes de musculação há no mínimo três meses. Os participantes foram avaliados quanto ao peso ealtura, força muscular da articulação do joelho (utilizando dinamômetro isocinético Biodex Multi-Joint Pro), teste de flexibilidade e avaliação de composiçãocorporal. A intervenção foi aplicada após a realização do treinamento muscular e consistiu em um programa de alongamentos estáticos ativos para os músculosisquiotibiais e quadríceps, após o treinamento de força, durante um período de 12 semanas. Observou-se um aumento para todas as variáveis de flexibilidade dogrupo intervenção, além de promover um aumento significativo das variáveis de pico de torque do membro dominante e não dominante na extensão e de potênciado membro dominante e não dominante na extensão e do membro dominante na flexão. Conclui-se que os exercícios de alongamento foram benéficos para o ganhode flexibilidade, além de constatar uma melhora nas variáveis isocinéticas do grupo intervenção nos membros dominante e não dominante em relação ao grupo controle.

Dissertation

Thesis

Full-text available

Jul 2023

Konstantin Warneke

Stretching is primarily used to improve flexibility, decrease stiffness of the muscle- tendon unit or reduce risk of injury. However, previous animal studies from 1970 to 1990 showed significant hypertrophy effects in skeletal muscle in response to chronic stretching intervention with stretching durations of 30 minutes to 24 hours per day. However, no study in humans was performed using comparatively long stretching durations of more than 30 minutes per day with a daily frequency. The present cumulative dissertation includes six studies aiming to investigate the effects of long-lasting static stretching training on maximum strength capacity, hypertrophy and flexibility in the skeletal muscle. Before starting own experimental studies, a meta-analysis of available animal research was conducted to analyze the potential of long-lasting stretching interventions on muscle mass and maximum strength. To induce long-lasting stretching on the plantar flexors and to improve standardization of the stretch training by quantifying the angle in the ankle joint while stretching, a calf muscle stretching orthosis was developed. In the following experimental studies, the orthosis was used to induce daily long- lasting static stretching stimuli with different stretching durations and intensities in the plantar flexors to assess different morphological and functional parameters. For this, a total of 311 participants were included in the studies and, dependent on the investigation, the effects of daily stretching for 10-120 minutes for six weeks were analyzed. Therefore, effects on maximal isometric and dynamic strength as well as flexibility of the plantar flexors were investigated with extended and flexed knee joint. The investigation of morphological parameters of the calf muscle was performed by determining the muscle thickness and the pennation angle by using sonographic imaging and the muscle cross-sectional area by using a 3 Tesla magnetic resonance imaging measurement. In animals, the included systematic review with meta-analysis revealed increases in muscle mass with large effect size (d = 8.51, p < 0.001), muscle cross-sectional area (d = 7.91, p < 0.001), fiber cross-sectional area (d = 5.81, p < 0.001), fiber length (d = 7.86, p < 0.001) and fiber number (d = 4.62, p < 0.001). The thereafter performed experimental studies from our laboratory showed a range of trivial to large increases in maximum strength of 4.84% to 22.9% with d = 0.2 to 1.17 and ROM of 6.07% to 27.3% with d = 0.16 to 0.87 dependent on stretching time, training level and testing procedure. Furthermore, significant moderate to large magnitude hypertrophy effects of 7.29 to 15.3% with d = 0.53 to 0.84 in muscle thickness and trivial to small increases of 5.68% and 8.82% (d = 0.16 to 0.3) in muscle cross-sectional area were demonstrated. The results are discussed based on physiological parameters from animal studies and in the front of knowledge in resistance training, suggesting mechanical tension to be one important factor to induce muscle hypertrophy and maximal strength increases. Further explanatory approaches such as hypoxia and changes in the muscle tendon unit are debated in the following. Since these studies are the first investigations on long-lasting stretch-mediated hypertrophy in humans, further research is needed to explore the underlying mechanisms and confirm the results in different populations to enhance the practical applicability for example in clinical populations when, e.g. counteracting muscular imbalances or sarcopenia in the elderly. https://pub-data.leuphana.de/frontdoor/index/index/docId/1318

Does Stretching Training Influence Muscular Strength? A Systematic Review With Meta-Analysis and Meta-Regression

Article

Full-text available

Aug 2022
J STRENGTH COND RES

Background Evidence regarding chronic stretching training is limited. This study aimed to review studies that performed stretching training and evaluated the effects on muscular strength. Methods Literature search was performed using three databases. Studies were included if compared the effects on strength following stretching training versus a non-training control group or stretching training combined with resistance training (RT) versus an RT-only group, following at least 4 weeks of intervention. The quality of the studies was assessed with the Downs & Black checklist. The meta-analyses were performed using a random-effects model with Hedges’ g effect size (ES). Results A total of 35 studies (n=1179), predominantly of medium and high quality, were included in the review. The interventions were carried out over a mean period of 8 weeks (4–24 weeks), 3 to 4 days per week, applying ⁓4 sets of stretching of ~1-minute duration. The meta-analysis for the stretching vs. non-training control group showed a significant small effect on improving dynamic (k=14; ES=0.33; p=0.007) but not isometric strength (k=8; ES=0.10; p=0.377), following static stretching programs (k=17; ES=0.28; p=0.006). When stretching was added to RT interventions, the main analysis indicated no significant effect (k=17; ES=-0.15; p=0.136); however, the meta-regression revealed a significant negative association with study length, whereby the longer the intervention the greater was the impairing effect of the stretching exercises on RT-induced strength gains (β=-0.100; p=0.004). Conclusions Chronic static stretching programs may increase dynamic muscular strength to a small magnitude. Performing stretching before RT and for a prolonged time (>8 weeks) may blunt the strength gains to a small-to-moderate magnitude. Performing stretching in sessions distant from RT sessions may be a strategy to not hinder strength development.

Alongamento estático associado ou não ao exercício resistido sobre a extensibilidade e força muscular em indivíduos saudáveis

Article

Full-text available

May 2015

Gladson Ricardo Flor Bertolini

Objetivo: Verificar a influência do alongamento estático associado ou não ao exercício resistido sobre a extensibilidade, força e dor muscular de início tardio, dos músculos isquiotibiais, em pessoas sedentárias saudáveis. Métodos: O grupo amostral foi composto por 29 voluntários, separados em 3 grupos: G1 - alongamento estático; G2 – exercício resistido com 70% da carga máxima; G3 – alongamento e exercício resistido. Para avaliar a extensibilidade, a força e a dor muscular de início tardio (DMIT) foi utilizada respectivamente, uma prancha goniométrica, um dinamômetro e um dolorímetro de pressão. O alongamento estático foi realizado em três séries de 30s cada, e o exercício resistido foi realizado com três séries de 10 repetições cada. Resultados: Na avaliação goniométrica, observou-se que houve diferenças significativas entre os grupos e que os valores de G1 foram maiores do que G3. Para avaliação da força muscular, houve diferença significativa, somente entre as avaliações. Na avaliação da DMIT, não houve diferença significativa. Conclusão: O alongamento e o treino resistido produziram ganho de extensibilidade muscular, quando realizados isoladamente; e as três formas utilizadas produziram ganho de força muscular, gerando DMIT.Palavras-chave: exercícios de alongamento muscular, força muscular, modalidades de fisioterapia.

The Effect of Static and Dynamic Stretching Exercises on Sprint Ability of Recreational Male Volleyball Players

Article

Full-text available

Aug 2019
Int J Environ Res Publ Health

The aim of the present trial was to investigate the effect of two stretching programs, a dynamic and a static one, on the sprint ability of recreational volleyball players. The sample consisted of 27 male recreational volleyball players (age 21.6 ± 2.1 years, mean ± standard deviation, body mass 80.3 ± 8.9 kg, height 1.82 ± 0.06 m, body mass index 24.3 ± 2.5 kg.m−2, volleyball experience 7.7 ± 2.9 years). Participants were randomly divided into three groups: (a) the first performing dynamic stretching exercises three times per week, (b) the second following a static stretching protocol on the same frequency, and (c) the third being the control group, abstaining from any stretching protocol. The duration of the stretching exercise intervention period was 6 weeks, with all groups performing baseline and final field sprinting tests at 4.5 and 9 m. The post-test sprint times were faster in both the 4.5 (p = 0.027, η2 = 0.188) and 9 m tests (p < 0.001, η2 = 0.605) compared to the pre-test values. A large time × group interaction was shown in both the 4.5 (p = 0.007, η2 = 0.341) and 9 m tests (p = 0.004, η2 = 0.363) with the static and dynamic stretching groups being faster in the post-test than in the pre-test, whereas no change was found in the control group. The percentage change in the 4.5 m sprint time correlated with volleyball experience (r = −0.38, p = 0.050), i.e., the longer the volleyball experience, the larger the improvement in the 4.5 m sprint. Thus, it is concluded that both stretching techniques have a positive effect on the velocity of recreational male volleyball players, when performed at a frequency of three times per week for 6 weeks under the same conditions as defined in the study protocol.

Effects of chronic stretching training on the torque of young adults

Article

Full-text available

Sep 2017

The aim of this study was to evaluate the effects of stretching training in the capacity of hamstring muscles torque maintenance in male young adults. Thirty-eight volunteers were randomly divided into two groups: Stretching Group (SG, n = 19) and Control Group (CG, n = 19). The training protocol consisted of three different static stretching exercises for hamstrings, performed in 3 repetitions, lasting 30s each, and 3 days.wk-1 , totalizing 270 seconds per session, during 6 weeks. Knee Range of Motion (ROM) was assessed by a goniometer and isometric peak torque (Pt), rate of torque maintenance (RTM-the resultant of the maximum and minimum isometric peak torque), rate of torque development (RTD-∆Force/∆Time) and impulse (I-area under the torque-time curve) were assessed through a load cell. Parametric results were analyzed by mixed model ANOVA. The ROM at post-training of SG was greater than at post-training of CG (163±4º vs. 141±3º Cohen's d = 5.25; p <0.001). The RTD increased after the stretching training when compared to pre post-training for both groups (23.34±8.8 N.s-1 vs.18.13±10.27 N.s-1 , Cohen's d = 0.54; p =0.044). Pt, RTM and I did not change. The stretching training for 6 weeks increased the ROM and RTD without interfering on the peak torque of young adult's hamstring muscles

Influence of chronic stretching on muscle performance: Systematic review

Article

Aug 2017

The aim of the current study was to investigate the influence of chronic stretching on muscle performance (MP) by a systematic review. The search strategy included MEDLINE, PEDro, Cochrane CENTRAL, LILACS, and manual search from inception to June 2016. Randomized and controlled clinical trials, non-randomized, and single group studies that have analyzed the influence of flexibility training (FT) (using any stretching technique) on MP were included. Differently, studies with special populations (children, elderly, and people with any dysfunction/ disease), and articles that have used FT protocols shorter than three weeks or 12 sessions were excluded. The MP assessment could have been performed by functional tests (e.g. jump, sprint, stretch-shortening cycle tasks), isometric contractions, and/or isotonic contractions. Twenty-eight studies were included out of 513. Seven studies evaluated MP by stretch-shortening cycle tasks, Ten studies evaluated MP by isometric contractions, and 13 studies assessed MP by isotonic contractions. We were unable to perform a meta-analysis due to the high heterogeneity among the included studies. In an individual study level analysis, we identified that 14 studies found positive effects of chronic stretching on MP. The improvements were observed only in functional tests and isotonic contractions, isometric contractions were not affected by FT. Therefore, FT might have an influence on dynamic MP. However, more studies are necessary to confirm whether FT can positively affect MP.

Eight weeks of dynamic stretching during warm-ups improves jump power but not repeated or single sprint performance

Article

Full-text available

Feb 2014
EUR J SPORT SCI

Abstract There is abundant research involving the acute effects of stretching on subsequent performance; however, there is little information on dynamic stretch training programmes on range of motion (ROM), power and speed measures. It was the objective of this research to examine the training consequences of active dynamic stretching (ADS) and static dynamic stretching (SDS). A repeated measures design compared the effects of 8 weeks of warm-ups incorporating two dynamic stretch modalities: ADS and SDS on squat jump (SJ), countermovement jump (CMJ), 20-m sprint performances and repeated sprint ability (RSA) and hip ROM in 37 male soccer players. SJ height (SDS: 4.6%; ADS: 5.3%; p <0.05), CMJ height (SDS: 5.3%; ADS: 3.4%; p<0.05), CMJ force (SDS: 7.2%; ADS: 12.7%; p<0.001) and CMJ peak power (SDS: 3.9%; ADS: 3.3%; p<0.05) increased significantly after SDS and ADS training compared to the control group (no significant change). Sprint performance and RSA were not affected by either of the dynamic stretch training regimens. The SDS and ADS training programmes elicited similar improvements in flexibility (SDS: 57.6%; ADS: 45.1%; p<0.01) compared to the non-significant changes in the control group. The inclusion of ADS and SDS within the regular warm-up of an 8-week training programme can improve not only flexibility but also jump power measures as well.

An examination of pre-activity and post-activity training practices of National Collegiate Athletic Association Division I and Division III baseball coaches

Article

Full-text available

Aug 2024

Baseball includes complex multi-joint and multi-planar activities involving a majority of the musculature of the body. Research pertaining to training practices including pre-activity and post-activity stretching continues to evolve along with related sport science recommendations. Therefore, the purpose of this study is to assess the pre-activity and post-activity warm-up, stretching, and training practices of National Collegiate Athletic Association (NCAA) Division I and Division III baseball coaches. A total of 686 questionnaires were distributed via email to head collegiate baseball coaches from NCAA Division I and III universities. The questionnaire was designed to gather demographic, professional, and educational information, as well as specific pre-activity and post-activity stretching usage by the coaches. The responses were examined by computing frequency counts and means where applicable. For the statistical analysis, both SPSS version 27.0 and JMP version 13.0 software packages were utilized. Pearson's Chi-squared tests were run where applicable. Results indicated just over 77% of coaches in the present study affirmed the importance of a pre-activity dynamic warmup. When comparing coaching specific certification to pre-activity flexibility practices, it is clear not all coaches comply with suggested pre-activity flexibility recommendations. This study indicates it is important for baseball coaches to re-evaluate their own practices, perhaps cross-checking them with practices of their peers and staying current with ongoing research.

THE EFFECTIVENESS OF ECCENTRIC EXERCISE AND STATIC STRETCHING IN IMPROVING THE CALF MUSCLE FLEXIBILITY IN UNIVERSITY MALE STUDENTS - A COMPARATIVE STUDY

Article

Full-text available

Jan 2024

p> Background: This study endeavoured to find the effectiveness of static stretching and eccentric training for the improvement of calf muscle flexibility in university students. Methodology: Forty university male students between the age group of 18-25 years volunteered to participate in the study. Anthropometric variables, i.e. height, weight, and Body Mass Index (BMI) measured. Result & Conclusion: Statistical analyses of data performed using the Statistical Package for the Social Sciences (SPSS) version 21.0. The level of significance was set at 0.05. The eccentric training group showed statistically significant improvements in active and passive calf muscle flexibility when compared to the static stretching group. Article visualizations: </p

Assessment of isokinetic hip muscle strength and predictors in patients with lower limb amputation: A cross-sectional study

Article

Full-text available

Oct 2023

Objectives The purpose of the study was to determine isokinetic features and analyze significant predictors related to activity level of patients with lower limb amputation. Patients and methods Forty-three male patients (mean age: 32.9±8.8 years; range, 21 to 50 years) with lower limb amputation were recruited consecutively for this cross-sectional study between March 1, 2022, and June 30, 2022. The hip flexor and extensor peak torques and total work were evaluated by an isokinetic dynamometer. The secondary outcome measure was the Amputee Mobility Predictor. A linear regression analysis was used to determine factors independently affecting Amputee Mobility Predictor scores. Results All data of patients with unilateral amputation, except for flexor (p=0.285) and extensor (p=0.247) peak torques on the dominant side, were higher than those of patients with amputation. Dominant side extensor peak torque was statistically higher than nondominant side extensor peak torque (59.4±30.7 vs. 43.4±32.0) in patients with bilateral amputation. No difference was detected between amputated and intact sides of patients with unilateral amputation. Both flexor and extensor total work on the amputated side of the patients with below-knee amputation were higher than the patients with above-knee amputations (63.5±21.1 vs. 94.1±34.3 and 67.1±34.0 vs. 113.0±51.5, respectively). Unilateral amputation (odds ratio: 7.442) and nondominant side extensor total work (odds ratio: 0.615) were found to be significant predictors related with amputee mobility predictor scale. Conclusion It is possible to have an idea about the possible activity level of the patients with lower limb amputation with the help of the predictors obtained in the current study.

Physiology of Stretch-Mediated Hypertrophy and Strength Increases: A Narrative Review

Article

Full-text available

Aug 2023
SPORTS MED

Increasing muscle strength and cross-sectional area is of crucial importance to improve or maintain physical function in musculoskeletal rehabilitation and sports performance. Decreases in muscular performance are experienced in phases of reduced physical activity or immobilization. These decrements highlight the need for alternative, easily accessible training regimes for a sedentary population to improve rehabilitation and injury prevention routines. Commonly, muscle hypertrophy and strength increases are associated with resistance training, typically performed in a training facility. Mechanical tension, which is usually induced with resistance machines and devices is known to be an important factor that stimulates the underlying signaling pathways to enhance protein synthesis. Findings from animal studies suggest an alternative means to induce mechanical tension to enhance protein synthesis, and therefore muscle hypertrophy by inducing high volume stretching. Thus, this narrative review discusses mechanical tension-induced physiological adaptations and their impact on muscle hypertrophy and strength gains. Furthermore, research addressing stretch-induced hypertrophy is critically analyzed. Derived from animal research, stretching literature exploring the impact of static stretching on morphological and functional adaptations was reviewed and critically discussed. No studies have investigated the underlying physiological mechanisms in humans yet, and thus the underlying mechanisms remain speculative and must be discussed in the light of animal research. However, studies that reported functional and morphological increases in humans commonly used stretching durations of >30 minutes per session of the plantar flexors, indicating the importance of high stretching volume, if the aim is to increase muscle mass and maximum strength. Therefore, the practical applicability seems limited to settings without access to resistance training (e.g., in an immobilized state at the start of rehabilitation), since resistance training seems to be more time efficient. Nevertheless, further research is needed to generate evidence in different human populations (athletes, sedentary, and rehabilitation patients) and to quantify stretching intensity.

Potential Effects of Dynamic Stretching on Injury Incidence of Athletes: A Narrative Review of Risk Factors

Article

Full-text available

May 2023
SPORTS MED

The use of dynamic stretching as a replacement for static stretching in the warm-up is widespread based on the reports of static stretching-induced performance impairments. While acute and chronic static stretching has been reported to reduce musculotendinous injuries, especially with explosive and change of direction actions, the influence of dynamic stretching on injury incidence lacks a similar volume of literature for acute and chronic responses. It was the objective of this narrative review to examine the acute and training effects of dynamic stretching on injury incidence and possible moderating variables such as dynamic stretching effects on range of motion, strength, balance, proprioception, muscle morphology, and psycho-physiological responses. One study demonstrated no significant difference regarding injury incidence when comparing a dynamic stretching-only group versus a combined dynamic stretching plus static stretching group. The only other study examined functional dynamic stretching training with injured dancers and reported improved ankle joint stability. However, several studies have shown that dynamic activity with some dynamic stretching exercises within a warm-up consistently demonstrates positive effects on injury incidence. Regarding moderating variables, while there is evidence that an acute bout of dynamic stretching can enhance range of motion, the acute and training effects of dynamic stretching on strength, balance, proprioception, and musculotendinous stiffness/compliance are less clear. The acute effects of dynamic stretching on thixotropic effects and psycho-physiological responses could be beneficial for injury reduction. However, the overall conflicting studies and a lack of substantial literature compared with SS effects points to a need for more extensive studies in this area.

Effect of a Six-Week Core Conditioning as a Warm-Up Exercise in Physical Education Classes on Physical Fitness, Movement Capability, and Balance in School-Aged Children

Article

Full-text available

Jul 2020
Int J Environ Res Publ Health

Whether the implementation of feasible, equipment-free, and simple core exercises in warm-up routines in physical education classes for school-aged children is beneficial remains unclear. Therefore, this study investigated the effects of a core conditioning in the warm-up routine of physical education classes on trunk muscular endurance, movement capability, and flexibility in this population. In these pre- and post-test control group experiments, 52 healthy, school-aged children (aged 10–11 years) were cluster randomized allocated to either the dynamic core exercise (DCE) group or general physical education (GPE) group. The DCE group performed a 10-min core exercise routine twice per week for six consecutive weeks; the GPE group performed traditional physical education warm-up exercises regularly. The children were assessed by conducting the trunk muscular endurance test (i.e., dynamic curl-up, static curl-up, plank, and lateral plank), functional movement screen (FMS), and single-leg balance test before and after the intervention. At the end of the intervention, the DCE group demonstrated a significant effect on trunk muscular endurance, movement capability (i.e., FMS scores), flexibility, and balance (each p < 0.001, effect size: 0.38–1.3). Furthermore, the DCE group showed significant improvements in all outcome measurements compared with the GPE group (p < 0.05, effect size: 0.29–1.68). These data may provide a reference for incorporating additional core stability exercises in the warm-up routine of physical education classes in school-aged children in the future.

A review of the effects of static stretching in human mobility and strength training as a more powerful alternative: Towards a different paradigm

Article

Jun 2020

Flexibility is a measurable physical capacity considered as a key component of physical fitness. Poor flexibility is usually attributed to excessive tension exerted by the antagonist muscles of the movement and, supported by weak scientific evidence, passive stretching is considered as the most effective intervention in the promotion of the muscle extensibility, in attempting to improve mobility. The proposal of this paper is a review of the effects of static stretching in human movement and a presentation of strength training as a more robust alternative based on scientific evidence. First, we try to define which factors influence the ability of the human body to move into their functional safety range of motion. Second, we present a critical scientific literature review of the effects of static stretching in the promotion of range of motion, injury prevention, and sports performance. Third, we propose alternatives to static stretching such as proprioceptive neuromuscular facilitation, dynamic stretching, and especially strength/resistance training, in the promotion of a better range of motion. Finally, we conclude that perhaps problems of flexibility/mobility should not be addressed with static processes, but with movement.

Effects of a Chronic Protocol of Stretching about the Capacity of a Muscle in Sustaining Prolonged Efforts

Article

Full-text available

Feb 2018

Aristela De Freitas Zanona

Effects of Dynamic Stretching Combined With Kinesio Taping on Performance of Baseball Players

Article

Full-text available

Sep 2018

This study aimed to investigate the acute effect of dynamic stretching (DS) with Kinesio taping (KT) on sprint, agility and balance in baseball athletes. Thirty healthy amateur baseball players were participated in the experiment. This study was a pretest-posttest control group design. Participants were matched and randomly assigned into KT group or control group (sham taping). A fitness trainer instructed the participants to perform DS sequentially. Three sets of stretching per muscle group were performed (14 times for each muscle of both legs) with a 1-minute recovery between sets over a distance of 20 m. Stretching muscles included anterior, posterior and medial thighs as well as calves. All subjects performed Y balance, 20-m sprint and 5-10-5 agility tests before and after the DS instruction. The results showed that there was no significant interaction effect between the groups and time in three tests. Both groups after receiving DS had significantly greater performance on Y balance test compared with baseline. Nevertheless, no significant difference on Y balance test was observed between the KT and control groups. Furthermore, no significant group and time main effects were noticed on 20-m sprint and 5-10- 5 agility tests. In conclusion, this study suggests that KT incorporated with DS cannot provide a synergistic effect on exercise performance of healthy baseball players. However, performing DS may improve the dynamic balance in the lower limb.

The Effect of Static Stretching in Agility and Isokinetic Force at Football Players

Article

Full-text available

Jun 2018

The repercussion is an essential of the football training, also called "Cool Down". Static stretching and slow running are typical activities of this section, but in the last few years static stretching has had a great infl uence on performance functionality and is one of the most debated topics in sports sciences and medicine. The aspiration of this research is to show the impact of recovery associated with static stretching and the agility performance of young football players. This research was conducted between August and November with a sample of 20 players age 12.1±0.3 years (range 11-13 years) separated into two groups-control and experimental. First measurements that have been initiated are body weight 40.6±6.5 kg, height 152.6±6.9 cm and agility performance (Ajax test 5x10 m and zigzag test with and without ball). Agility was measured with electronic photocells' , with a measurement of .01 sec. Experimental testing proposed that both groups have completed the regular training program, while the experimental group (despite the control group) during the recuperation (cool down) except running, they conveyed out the experimental treatment / static stretching exercises. Each exercise lasts at least 20 seconds. After completing the experimental program members in both groups underwent fi nal measurements. The results that were reached by univariate analysis of variance (ANOVA) at initial and fi nal measurements, have shown insignifi cant statistical values between the control and experimental group in the agility performance.

EXERCÍCIOS DE ALONGAMENTO: PRESCRIÇÃO E EFEITOS NA FUNÇÃO MUSCULOESQUELÉTICA DE ADULTOS E IDOSOS

Article

Full-text available

Mar 2018

Introduction: Stretching exercises have been included in training and rehabilitation programs to improve the flexibility of adults and older people. However, there is no consensus in the literature about the recommendations for stretching prescription. Objective: The aim of this study was to present an update of recent evidence about the prescription and the musculoskeletal effects of stretching exercises in adults and older. Method: Articles were searched on major databases and related to the period from 2006 to 2017, with the following descriptors: “muscle stretching exercise”, “long-term effect”, “elderly”, “exercício de alongamento muscular”, “efeitos a longo prazo”, and “idoso”. Results: After the analysis, 31 articles were included. The literature reported that the duration of the stretching should be between 10 to 30 seconds, each repetition, for young adults, and from 30 to 60 seconds for the elderly. Regarding acute effects, it was observed that for young adults, stretching durations up to 60 seconds may impair muscle strength performance, what does not seem to occur with elderly people. The main chronic effects found for young and elderly adults were an enhancement in flexibility and range of motion, and for the elderly, it was also observed improvement on torque, balance, gait, mobility, and functionality. The wide methodological variability of the articles analyzed impairs the establishment of a consensus. Conclusion: It is recommended that the stretching exercise must be prescribed considering the evidence for the specific population, i.e., adult or elderly people, as well as the goal to be achieved.

Physiological and methodological aspects of rate of force development assessment in human skeletal muscle

Article

Full-text available

Nov 2017
CLIN PHYSIOL FUNCT I

Rate of force development (RFD) refers to the ability of the neuromuscular system to increase contractile force from a low or resting level when muscle activation is performed as quickly as possible, and it is considered an important muscle strength parameter, especially for athletes in sports requiring high-speed actions. The assessment of RFD has been used for strength diagnosis, to monitor the effects of training interventions in both healthy populations and patients, discriminate high-level athletes from those of lower levels, evaluate the impairment in mechanical muscle function after acute bouts of eccentric muscle actions and to estimate the degree of fatigue and recovery after acute exhausting exercise. Notably, the evaluation of RFD in human skeletal muscle is a complex task since influenced by numerous distinct methodological factors including mode of contraction, type of instruction, method used to quantify RFD, devices used for force/torque recording and ambient temperature. Another important aspect is our limited understanding of the mechanisms underpinning rapid muscle force production. Therefore, this review is primarily focused on 1) describing the main mechanical characteristics of RFD; 2) analyzing various physiological factors that influence RFD; and 3) presenting and discussing central biomechanical and methodological factors affecting the measurement of RFD. The intention of this review is to provide more methodological and analytical coherency on the RFD concept, which may aid to clarify the thinking of coaches and sports scientists in this area.

The effects of 4 weeks stretching training to the point of pain on flexibility and muscle tendon unit properties

Article

Full-text available

Aug 2017
EUR J APPL PHYSIOL

Purpose: The purpose of this study was to compare the benefits and possible problems of 4 weeks stretching when taken to the point of pain (POP) and to the point of discomfort (POD). Methods: Twenty-six physically active women (20 ± 1.1 years) took part in group-based stretching classes of the hamstring muscles, 4 times per week for 4 weeks, one group one stretching to POD, the other to POP. Passive stiffness, joint range of motion (ROM), maximal isometric torque and concentric knee flexion torque, were measured before training and 2 days after the last training session. Results: Hip flexion ROM increased by 14.1° (10.1°-18.1°) and 19.8° (15.1°-24.5°) and sit-and-reach by 7.6 (5.2-10.0) cm and 7.5 (5.0-10.0) cm for POD and POP, respectively (Mean and 95% CI; p < 0.001 within group; NS between groups), with no evidence of damage in either group. Despite the large increases in flexibility there were no changes in either compliance or viscoelastic properties of the muscle tendon unit (MTU). Conclusion: Hamstrings stretching to POP increased flexibility and had no detrimental effects on muscle function but the benefits were no better than when stretching to POD so there is no justification for recommending painful stretching. The improvements in flexibility over 4 weeks of stretching training appear to be largely due to changes in the perception of pain rather than physical properties of the MTU although less flexible individuals benefited more from the training and increased hamstring muscle length.

EFEITO AGUDO DO VOLUME DE ALONGAMENTO ESTÁTICO NO DESEMPENHO NEUROMUSCULAR DE JOVENS E IDOSAS

Article

Full-text available

Apr 2017

Introdução: Os exercícios prévios de alongamento estático (AE) podem promover decréscimo transitório da força muscular. Características dos protocolos de AE e da amostra estudada podem interferir no desempenho neuromuscular subsequente às rotinas de alongamento. Objetivo: Investigar o efeito agudo de dois diferentes volumes de AE sobre o sistema neuromuscular de mulheres jovens e idosas durante a execução do leg press horizontal. Métodos: Vinte e quatro mulheres (12 jovens e 12 idosas), aparentemente saudáveis, compareceram ao local de realização do experimento em seis ocasiões distintas. Nas três primeiras visitas realizaram-se coleta dos dados pessoais, de dados antropométricos, familiarização com o protocolo de AE e registro de esforço isométrico no leg press horizontal. Nas três últimas visitas, foram realizados registros da curva força-tempo isométrica e atividade eletromiográfica (EMG) dos músculos vasto medial e vasto lateral após realização de uma de três condições experimentais: controle (sem alongamento), alongamento com volume total de 60 segundos e 120 segundos. A ordem das condições experimentais foi aleatorizada. O protocolo de AE envolveu três exercícios executados em duas séries de 30 segundos (AE60) ou em quatro séries de 30 segundos (AE120). O teste ANOVA two-way foi utilizado para análises dos dados. Resultados: Nenhuma das rotinas de AE acarretou alteração de taxa de desenvolvimento de força (TDF), contração voluntária máxima e atividade EMG nas mulheres jovens e idosas. Conclusões: Diferentes volumes de AE, em conformidade com recomendações atuais, não influenciaram o desempenho neuromuscular de mulheres jovens e idosas no exercício leg press horizontal.

The acute benefits and risks of passive stretching to the point of pain

Article

Full-text available

Jun 2017
EUR J APPL PHYSIOL

Purpose: This study evaluated the acute effects of two different stretch intensities on muscle damage and extensibility. Methods: Twenty-two physically active women (age 20 ± 1.0 years) were divided into two matched groups and undertook eight sets of 30-s passive hamstring stretching. One group stretched to the point of discomfort (POD) and the other to the point of pain (POP). Hamstring passive torque, sit and reach (S&R), straight leg raise (SLR), and markers of muscle damage were measured before, immediately after stretching and 24 h later. Results: S&R acutely increased and was still increased at 24 h with median (interquartile range) of 2.0 cm (0.5-3.75 cm) and 2.0 cm (0.25-3.0 cm) for POP and POD (p < 0.05), respectively, with no difference between groups; similar changes were seen with SLR. Passive stiffness fully recovered by 24 h and there was no torque deficit. A small, but significant increase in muscle tenderness occurred at 24 h in both groups and there was a very small increase in thigh circumference in both groups which persisted at 24 h in POP. Plasma CK activity was not raised at 24 h. Conclusion: Stretching to the point of pain had no acute advantages over stretching to the discomfort point. Both forms of stretching resulted in very mild muscle tenderness but with no evidence of muscle damage. The increased ROM was not associated with changes in passive stiffness of the muscle but most likely resulted from increased tolerance of the discomfort.

Isokinetic Evaluation of the Hip Flexor and Extensor Muscles: A Systematic Review

Article

Full-text available

Dec 2016
J SPORT REHABIL

Introduction: Isokinetic dynamometry testing is a safe and reliable method accepted as the "gold standard" in the evaluation of muscle strength in the open kinetic chain. Isokinetic hip examinations face problems in the standardization of the position of the equipment axis; in the individual being examined; in the adjustment of the lever arm and in stabilization strategies for the patients during the tests. Identification of the methodologic procedures with best reproducibility is also needed. Objective: The objective of this study was to review the literature to evaluate the parameters used for the isokinetic evaluation of the hip flexor and extensor muscles and its reproducibility. Method: This is a systematic literature review of the Cochrane, LILACS, PEDro, PubMed, and SciELO databases. The inclusion criteria were papers on the evaluation of hip flexor and/or extensor muscular strength with an isokinetic dynamometer and papers that analyzed the ICC or Pearson's reproducibility. The information extracted was: positioning of the patient; positioning of the dynamometer axis; positioning of the lever arm; angular speed; sample size, pathology; type of contraction and ICC and Pearson's results. Results: On the databases 204 papers were found, from which 14 were selected that evaluated hip flexor and extensor muscles, involving 550 individuals who were submitted to an isokinetic hip evaluation. Five papers obtained the best result in reproducibility and had their methodology analyzed. Conclusion: In order to obtain better reproducibility of the isokinetic evaluation of the hip flexor and extensor muscles, the following recommendations must be followed: the individual must be positioned in the supine position and the dynamometer axis must be aligned with the greater trochanter of the femur. The positioning of the lever arm must be in the most distal region of the thigh possible. The angular speed used to analyze torque peak and muscle work was 60°/s, and to evaluate the muscle power it was 180°/s, with concentric and eccentric contractions being analyzed.

High intensity exercise and flexibility of the lower limbs: Dose-effect study

Article

Full-text available

Aug 2016

Introduction: Sports scientists have been studying the phenomenon involving different types of exercises and their influence on other activities. Stretching exercises have a negative influence on muscular strength and power output, as do high intensity or long duration cardiovascular training. Nevertheless, several studies have found the opposite to be true Nevertheless, few investigations have studied the opposite. Objective: To determine whether high intensity power exercise influences muscular flexibility in an acute manner. Methods: A sample of forty-three male and female young adults aged between 18 and 28 years, with a mean age of 22.88 + 3.04 years, who have practiced physical activity for at least six months. To determine flexibility, the sit-and-reach test was used. For the high intensity training, a 45º leg press was used. A 10-rep movement was performed at 85% of 1 RM, in both pre- and post-tests. Statistic analysis was conducted using the ANOVA and Scheffer's post-hoc tests, with a level of significance for differences of < 0.05. Results: Comparison of the pre- and post-tests proved to be statistically significant from the baseline from the fourth to the seventh repetitions. Conclusion: Strength exercises at 85% of 1RM seem to significantly increase range of motion in an acute manner, and the growth of this range of motion has a dose-effect response.

Comparison the effects of acute and long-term static and dynamic warm-up protocols on fitness and motor performance in skilled female Gymnast

Data

Sep 2015

Comparison the effects of acute and long-term static and dynamic warm-up protocols on fitness and motor performance in skilled female Gymnast

Article

Full-text available

Jun 2015

Purpose: The aim of this study was to investigate the effects of acute and long-term static and dynamic warm-up protocols on fitness and motor performance in skilled female Gymnast. Methodology: For this purpose, 24 female skilled gymnasts (with a mean age of 9.66±1.43 height 129.91±13.68 cm, weight 28.45±8.48 kg and BMI 16.44±2.16 kg/m 2 ) were selected. Subjects were randomly assigned to three groups (general warm-up, general warm-up and static stretching and general warm-up and dynamic stretching). The first protocol consisted of a 10 minute jogging, second protocol consisted of jogging and static stretching and third protocol consisted of jogging and dynamic stretching in muscles used in performing the skill. Subjects were tested before and after acute protocol and four weeks as the using different protocols. Anaerobic power and a 20-meters sprinting was recorded digitally by Bosco test and Sprint digital timer respectively . Also for score the subjects, two experienced referees certified by Board of gymnastics were used. Statistical analysis of data was performed through ANOVA with repeated measurements and Bonferroni post hoc test at significance level (p≤0.05). Findings: The results of this study showed, significant differences in acute and long-term dynamic protocols at balance the vault Performance (p=0.001). As well as anaerobic power and sprinting performance showed a significant increase in long-term dynamic warm-up protocol compared to the acute phase (p=0.04). While balance the vault Performance, anaerobic power and sprinting 20 meters significantly decrease after a long-term static warm-up protocol compared to the acute phase (p=0.001). Conclusion: Therefore, it seems that dynamic stretching by post-activation potentiation and optimal muscle temperature cause better performance and in contrast, static stretching cause less performance due to decreased muscle activation and less muscle stiffness and Based on the findings of this research, Warm up in the long-term compared to acute warm-up causes further development of the balance the vault, anaerobic power and sprint Performance. Keywords: Dynamic warm-up, Static warm-up, Balance the Vault, anaerobic power, sprint

Stretching with whole body vibration versus traditional static stretches to increase acute hamstring range of motion

Article

Anastasia Elizabeth Bourne

Influence of stretching hamstring and quadriceps femoral muscles on knee peak torque and maximum power

Article

Full-text available

Dec 2009

Muscle stretching is often used in sports practice in order to increase muscle flexibility and joint range of motion. However, many studies have shown that muscle torque production may be reduced after stretching. The purpose of this work was to assess immediate and late effects of stretching, by proprioceptive neuromuscular facilitation (PNF) techniques, on knee peak torque and maximum power. Fifteen young sedentary female subjects were evenly distributed into three groups: AG, submitted to 12 PNF stretching sessions along four weeks; BG, submitted to only one stretching session just before the final evaluation; and GC, submitted to passive knee mobilization so as not to produce muscle stretching. All of them were assessed, before and after the four-week study, as to knee range of motion (ROM) flexion and extension, as well as to isokinetic dynamometry; variables analysed were knee ROM, peak torque and maximum power. Significant mean ROM differences were found between the three groups (p<0.001), but no differences in isokinetic measures (p>0.05). A and B groups showed increased ROM at the post-test, and only the C group showed significant increase in all isokinetic variables (p<0.05). Results then suggest that PNF stretching, performed with adequate duration and intensity, may be done before sports practice with no decrease in muscle strength.

Article

Oct 2013

The effects of hamstring stretching exercises on pain intensity and function in low back pain patients: A systematic review with meta-analysis of randomized controlled trials

Article

Full-text available

Jul 2024

Objectives This meta-analysis aims to synthesize the available data on the effectiveness of hamstring stretching exercises in relieving pain intensity and improving function for patients with low back pain. Methods Google Scholars, PubMed, Embase, Cochrane, MEDLINE, CNKI, Wanfang, and VIP were searched from inception to August 2023. We included randomized controlled trials that investigated the effectiveness of hamstring stretching exercises in patients with low back pain. The primary outcomes assessed were pain intensity, hamstring muscle flexibility, and function. Study selection, data extraction, and assessment of risk of bias were performed independently by two reviewers. Results Our searches retrieved 344 trials, of which 14 met the inclusion criteria for this review (n = 735 participants). The combined meta-analysis showed hamstring stretching resulted in lower pain scores (standardized mean difference = −0.72, 95% confidence interval: −1.35 to −0.09; I² = 89%, p = 0.03) in different categories of low back pain. Subgroup analysis showed that hamstring stretching led to a larger range of motion for cases of back pain with radiating pain (standardized mean difference = 2.39, 95% confidence interval: 1.76 to 3.02; I² = 0%, p < 0.001). The combined meta-analysis revealed that hamstring stretching resulted in lower Oswestry Disability Index scores in comparison to regular treatment, particularly in individuals suffering from low back pain across all subtypes (mean difference = −6.97, 95% confidence interval: −13.34 to −0.60; I² = 95%, p = 0.03). Conclusions This meta-analysis demonstrates the effectiveness of hamstring stretching exercises in reducing pain intensity in various categories of low back pain and improving the straight leg raise in patients experiencing back pain with radiating pain. Additionally, it highlights the improvement in function for patients with back pain across all subtypes.

Effects of Chronic Static Stretching on Maximal Strength and Muscle Hypertrophy: A Systematic Review and Meta-Analysis with Meta-Regression

Article

Full-text available

Apr 2024

Background Increases in maximal strength and muscle volume represent central aims of training interventions. Recent research suggested that the chronic application of stretch may be effective in inducing hypertrophy. The present systematic review therefore aimed to syntheisize the evidence on changes of strength and muscle volume following chronic static stretching. Methods Three data bases were sceened to conduct a systematic review with meta-analysis. Studies using randomized, controlled trials with longitudinal (≥ 2 weeks) design, investigating strength and muscle volume following static stretching in humans, were included. Study quality was rated by two examiners using the PEDro scale. Results A total of 42 studies with 1318 cumulative participants were identified. Meta-analyses using robust variance estimation showed small stretch-mediated maximal strength increases (d = 0.30 p < 0.001) with stretching duration and intervention time as significant moderators. Including all studies, stretching induced small magnitude, but significant hypertrophy effects (d = 0.20). Longer stretching durations and intervention periods as well as higher training frequencies revealed small (d = 0.26–0.28), but significant effects (p < 0.001–0.005), while lower dosage did not reach the level of significance (p = 0.13–0.39). Conclusions While of minor effectiveness, chronic static stretching represents a possible alternative to resistance training when aiming to improve strength and increase muscle size. As a dose-response relationship may exist, higher stretch durations and frequencies as well as long program durations should be further elaborated.

Investigating The Acute Effects of Different Warm-Up Protocols on Sprint Performance in Female Volleyball PlayersKadın Voleybolcularda Farklı Isınma Protokollerinin Sprint Performansına Akut Etkisinin İncelenmesi

Article

Full-text available

Sep 2023

The number of studies on warm-up protocols has increased in recent years. However, there are very few studies that are specific to the population of female athletes and consist of a large number of participants. This study was designed to investigate the effects of 3 different warm-up protocols on sprinting performance in young female volleyball players. A total of 62 licensed female volleyball players aged 13-17 years participated voluntarily. There were 3 sessions in the study. The participants were randomly divided into a warm-up group (GWG), a dynamic stretch group (DSG) and a static stretch group (SSG). After completing the warm-up protocols, the groups underwent a 5-minute transition period. The 20-metre sprint performance test was then performed. Data analysis was performed with the Python programming language and IBM SPSS 26 software. Shapiro-Wilk and Kolmogorov-Smirnov tests and kurtosis and skewness checks were performed. The data were indicated to be normally distributed (p> 0,05). Repeated Measures Anova test was used to detect the differences and the significance level was chosen as α=0,05. When the results were examined, it was found that there was no statistically significant difference between the GWG and SSG 20 meter sprint time values (p>0,05), whereas when the DSG and GWG and SSG 20 metre sprint time values were compared, it was found that the DSG group's sprint time improved statistically significantly (p

Chronic Effects of Static Stretching Exercises on Muscle Strength and Power in Healthy Individuals Across the Lifespan: A Systematic Review with Multi-level Meta-analysis

Article

Full-text available

Jan 2023
SPORTS MED

Background: The current literature on the chronic effects of static stretching (SS) exercises on muscle strength and power is unclear and controversial. Objective: To examine the chronic effects of SS exercises on muscle strength and power as well as flexibility in healthy individuals across the lifespan. Design: Systematic review with meta-analysis of (randomised) controlled trials. Data sources: A systematic literature search was conducted in the databases PubMed, Web of Science, Cochrane Library, and SPORTDiscus up to May 2022. Eligibility criteria for selecting studies: We included studies that investigated the chronic effects of SS exercises on at least one muscle strength and power outcome compared to an active/passive control group or the contralateral leg (using between- or within-study designs) in healthy individuals, irrespective of age, sex, and training status. Results: The main findings of 41 studies indicated trivial-to-small positive effects of chronic SS exercises on muscle strength (standardised mean difference [SMD]=0.21, [95% CI=0.10 to 0.33], p=0.001) and power (SMD=0.18, [95% CI=0.12 to 0.25], p<0.001). For flexibility, moderate-to-large increases were observed (SMD=0.96, [95% CI=0.69 to 1.23], p<0.001). Subgroup analyses, taking the participants' training status into account, revealed a larger muscle strength improvement for sedentary (SMD=0.58, p<0.001) compared to recreationally active participants (SMD=0.16, p=0.029). Additionally, larger flexibility gains were observed following passive (SMD=0.97, p<0.001) compared to active SS exercises (SMD=0.59, p=0.001). SS’s chronic effects on muscle strength were moderated by the proportion of females in the sample (β=0.004, p=0.042), with higher proportions experiencing larger gains. Other moderating variables included mean age (β=0.011, p<0.001), with older individuals showing larger muscle strength gains, and the number of repetitions per stretching exercise and session (β=0.023, p=0.004 and β=0.013, p=0.008, respectively), with more repetitions associated with larger muscle strength improvements. Muscle power was also moderated by mean age (β=0.006, p=0.007) with larger gains in older individuals. The meta-regression analysis indicated larger flexibility gains with more repetitions per session (β=0.094, p=0.016), more time under stretching per session (β=0.090, p=0.026), and more total time under stretching (β=0.078, p=0.034). Conclusion: The main findings indicated that chronic SS exercises have the potential to improve muscle strength and power. Such improvements appear to benefit sedentary more than recreationally active participants. Likewise, chronic SS exercises result in a marked enhancement in flexibility with larger effects of passive, as compared to active, SS. Results of the meta-regression analysis for muscle strength indicated larger benefits of chronic SS exercises in samples with higher proportions of females, older participants, and higher number of repetitions per stretching exercise and session. For muscle power, results suggested larger gains for older participants. Regarding flexibility, findings indicated larger benefits following a higher number of repetitions per exercise and longer time under stretching per session as well as longer total time under stretching.

The effects of 12 weeks of static stretch training on the functional, mechanical, and architectural characteristics of the triceps surae muscle–tendon complex

Article

Full-text available

Jun 2021
EUR J APPL PHYSIOL

Purpose We investigated the effects of 12 weeks of passive static stretching training (PST) on force-generating capacity, passive stiffness, muscle architecture of plantarflexor muscles. Methods Thirty healthy adults participated in the study. Fifteen participants (STR, 6 women, 9 men) underwent 12-week plantarflexor muscles PST [(5 × 45 s-on/15 s-off) × 2exercises] × 5times/week (duration: 2250 s/week), while 15 participants (CTRL, 6 women, 9 men) served as control (no PST). Range of motion (ROM), maximum passive resistive torque (PRT max ), triceps surae architecture [fascicle length, fascicle angle, and thickness], passive stiffness [muscle–tendon complex (MTC) and muscle stiffness], and plantarflexors maximun force-generating capacity variables (maximum voluntary contraction, maximum muscle activation, rate of torque development, electromechanical delay) were calculated Pre, at the 6th (Wk6), and the 12th week (Wk12) of the protocol in both groups. Results Compared to Pre, STR ROM increased ( P < 0.05) at Wk6 (8%) and Wk12 (23%). PRT max increased at Wk12 (30%, P < 0.05), while MTC stiffness decreased (16%, P < 0.05). Muscle stiffness decreased ( P < 0.05) at Wk6 (11%) and Wk12 (16%). No changes in triceps surae architecture and plantarflexors maximum force-generating capacity variables were found in STR ( P > 0.05). Percentage changes in ROM correlated with percentage changes in PRT max ( ρ = 0.62, P = 0.01) and MTC stiffness ( ρ = − 0.78, P = 0.001). In CTRL, no changes ( P > 0.05) occurred in any variables at any time point. Conclusion The expected long-term PST-induced changes in ROM were associated with modifications in the whole passive mechanical properties of the ankle joint, while maximum force-generating capacity characteristics were preserved. 12 weeks of PST do not seem a sufficient stimulus to induce triceps surae architectural changes.

Türk Spor Bilimleri Dergisi Türk Spor Bil Derg The Journal of Turkish Sport Sciences J Turk Sport Sci Suat POLAT 1 ORİJİNAL ARAŞTIRMA ORIGINAL RESEARCH Isınma Seansında Uygulanan Dinamik ve Statik Germe Egzersizlerinin Performans Üzerine Etkileri Özet

Article

Oct 2019

Bu araştırmada 6 hafta süresince ısınma seansında uygulanan statik ve dinamik esnetme türlerinin genç futbolculardaki esneklik, sürat ve yön değiştirmeli koşular üzerindeki etkilerini ortaya koymak amaçlandı. Çalışmaya İzmir genç amatör futbol liginde oynayan, toplam 16 kişiden oluşan gönüllü futbolcular katılmıştır (17,62±1,02 yaş, 176,25±0,072 cm boy, 67,67±13,27 kg ağırlık). İlk aşamada ön test olarak(6 haftalık antrenman programı öncesinde) sporcuların uzan eriş testleri, ikinci aşamada yön değiştirmeli koşu performansları, üçüncü aşamada ise sürat yetisine ait özellikleri birer gün aralıklarla ölçüldü. Ölçümlerin sonrasında ise 6 haftalık antrenman programı haftada 3 gün olacak şekilde uygulandı. 6 haftalık antrenmanlar sonrasında son test aşamasında, ilk olarak uzan eriş testleri, sonrasında yön değiştirmeli koşu performansları, üçüncü aşamada ise sürat yetisine ait özellikleri birer gün aralıklarla ölçüldü. Elde edilen verilere göre statik esnetme grubuna dâhil olan sporcuların otur eriş düzeylerinde artış elde edilirken (p=0,07**), sürat ve yön değiştirmeli koşu yetilerinde dinamik esnetme grubuna göre statik gruba ait değerlerde daha kötü performans değerleri elde edilmiştir (p=0,03**). Dinamik esnetme uygulayan grubun ise otur eriş testlerinde gelişim sağlanamamışken, yön değiştirmeli koşu ve sürat yetilerinde statik gruba göre daha pozitif değerlere sahip oldukları saptanmıştır. Bu çalışmanın sonucuna göre; 6 hafta boyunca ısınma seanslarında uygulanan dinamik esnetme hareketleri statik esnetme hareketlerine göre sürat ve yön değiştirmeli koşulara daha olumlu etki ettiği ortaya çıkartırken, statik esnetme türünün eklem hareket genişliğine daha olumlu etkileri olduğu sonuçlarını ortaya çıkartmıştır.

Chronic Effects of Static and Dynamic Stretching on Hamstrings Eccentric Strength and Functional Performance: A Randomized Controlled Trial

Article

Feb 2019

Barbosa, GM, Trajano, GS, Dantas, GAF, Silva, BR, and Vieira, WHB. Chronic effects of static and dynamic stretching on hamstrings eccentric strength and functional performance: A randomized controlled trial. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to investigate the effect of static or dynamic stretching training program on hamstrings eccentric peak torque and functional performance. Forty-five active healthy men were randomly allocated into 3 groups (n = 15 per group): no stretching (control), static stretching (3 sets of 30 seconds), and dynamic stretching (3 sets of 30 repetitions). Static and dynamic stretching protocols on the hamstring muscles were performed 3 times a week until complete 10 sessions. Isokinetic knee flexor eccentric peak torque (60°·s), triple hop distance, and modified 20-m sprint time were assessed in a random order before and after stretching training. A mixed-design analysis of variance was performed, with an alpha level of 0.05. There was a significant decrease of eccentric peak torque (p ≤ 0.0001, -15.4 ± 10.4%, within-group effect size: 1.03) after static stretching training. The static stretching training reduced eccentric torque when compared with no stretching (-7.6 ± 21.7%, between-group effect size: 0.50) and dynamic stretching (-7.8 ± 29.8%, between-group effect size: 0.51). Moreover, the reached distance on triple hop test was also reduced after static stretching protocol (p = 0.009, -3.7 ± 4.1%, within-group effect size: 0.29). These findings suggest that static stretching training is sufficient to produce meaningful reductions on hamstrings eccentric torque and functional performance. Based on the results of this study, caution should be taken when prescribing of static stretching training in isolation when the purpose is to improve performance, and indirectly, to prevent hamstring strain injuries due to its possible negative effects on hopping performance and knee flexor eccentric torque.

Chronic Effects of a Static Stretching Program on Hamstring Strength

Article

Jan 2019

Abstract Nakao, S, Ikezoe, T, Nakamura, M, Umegaki, H, Fujita, K, Umehara, J, Kobayashi, T, Ibuki, S, and Ichihashi, N. Chronic effects of a static stretching program on hamstring strength. J Strength Cond Res XX(X): 000–000, 2019—This study investigated the effects of a 4-week static stretching (SS) program on isokinetic and isometric knee flexor peak torque and angle of peak torque. Thirty healthy men (age, 22.7 ± 2.2 years) were randomized to receive either of the following: (a) a 4-week stretch intervention for the hamstrings (SS intervention group; n = 15) or (b) no intervention (control group; n = 15). The maximum pain-free knee angle, passive stiffness, which was determined by a slope of torque-angle curve, isometric and isokinetic (at 60°·s−1 and 180°·s−1) peak torque, and angle of peak torque for knee flexors were measured before and after 4 weeks. After 4 weeks, passive stiffness decreased significantly in the intervention group. There were no significant changes in isometric and isokinetic (neither at 60°·s−1 nor at 180°·s−1) peak torque, or angle of peak torque at 180°·s−1. A significantly increased peak extension angle at 60°·s−1 was observed in the intervention group. These results suggest that SS intervention is effective for decreasing musculotendinous unit stiffness of the hamstrings and that an SS program influences the angle of peak torque, whereas no significant changes occur in peak torque. Because a previous study suggests that angle of peak torque is associated with hamstring strain injuries, the results of this study would be helpful when considering the training program for preventing or treating hamstring strain injuries.

Paradigma Inflexível, 2018 - Revisão Narrativa Acerca do Treino da Mobilidade.

Conference Paper

Feb 2018

Historial do artigo: O presente artigo expressa uma opinião fundamentada em evidência e lógica. Foi elaborado e registado em 2013 e lançado a público no âmbito de ações de formação em várias certificações em exercício organizadas pelo autor, fazendo parte da documentação de apoio entregue aos alunos. As duas seguintes revisões (2016 e 2017) tiveram como revisor o Professor José Vilaça-Alves, onde se acrescentaram algumas secções de texto e a pesquisa científica atualizada. A versão de 2017 foi apresentada a público no 1o Congresso Internacional Exercise Summit (Oeiras, Portugal, Maio de 2017). A presente versão (2018), já tendo como revisor o Professor José Afonso Neves, é a última versão revista pelo autor, com a expansão das últimas secções, que se referem às verdadeiras causas da falta de flexibilidade e aos métodos mais vantajosos para a sua melhoria. Problema: A capacidade motora designada de flexibilidade é uma componente importante do movimento humano e, consequentemente, do fitness físico. Contudo, a forma de desenvolvimento desta capacidade não tem sido consensual, principalmente no que respeita às causas da sua pouca expressividade. Habitualmente, esta tem sido atribuída à falta de extensibilidade muscular antagonista e não às possíveis debilidades na capacidade de coordenação entre a musculatura agonista, antagonista e sinergista do movimento, que confere o arco articular analisado. Desta forma, a utilidade do alongamento do tipo passivo estático, aplicado à musculatura antagonista, com o propósito do aumento da amplitude do movimento articular (entre outros objetivos), embora seja a intervenção mais utilizada, tem sido colocada em causa. Assim, o objetivo do presente artigo foi efetuar uma reflexão crítica sobre esta problemática, tendo como base o raciocínio lógico e a revisão da literatura científica. Será dado enfâse aos efeitos do treino da flexibilidade em diversos domínios: nos níveis de força, na prevenção de lesões, no desempenho desportivo e na estrutura e função muscular. Será, igualmente, efetuada uma reflexão sobre o efeito das diferentes técnicas de treino da flexibilidade, tais como a facilitação neuromuscular propriocetiva (PNF) e o alongamento dinâmico. Serão abordados os efeitos do treino com resistências na flexibilidade e na capacidade de produzir força. Recursos bibliográficos: Para o efeito, foram utilizados manuais de referência em fisiologia humana (p.e. Joint Structure and Function; Principles of Neural Science), bem como da área da prescrição de exercício, e revistos cerca de 100 artigos científicos (dos quais 34 são revisões), que relacionam alongamento e/ou treino com resistências com as capacidades motoras flexibilidade e força, no desempenho desportivo, na prevenção ou incidência de lesão, na estrutura e na função neural muscular. Os estudos usados apresentam probabilidade de erro inferior a 5%, mas nem todos reportam as magnitudes dos efeitos observados (i.e., effect sizes). Conclusões: Tendo como base a revisão da literatura científica consultada e a reflexão lógica efetuada sobre a mesma, concluímos que, à luz dos conhecimentos presentes, o alongamento do tipo passivo estático pode não ser útil na obtenção de flexibilidade ativa (funcional) e, mesmo que o seja, comportará uma diminuição dos níveis de força muscular – à custa de alterações estruturais e neurais negativas. O aumento da extensibilidade muscular – e o consequente incremento de amplitude articular –, que é verificado com o treino de alongamento, é maioritariamente causado por inibição neural aferente e eferente. São verificadas alterações nas propriedades estruturais musculares, tais como a viscoelasticidade ou o comprimento, que, apesar de contribuírem também para o acréscimo de amplitude articular, são de menor relevância que os efeitos neurais. Efeitos estes que detêm um potencial negativo nos níveis de força. O alongamento pode ter um efeito negativo no desempenho desportivo, não previne lesões e os aumentos de flexibilidade que gera, passivos apenas, não se transferem necessariamente para a amplitude funcional. O treino com resistências pode melhorar a flexibilidade ativa, mesmo com o uso de contrações musculares isométricas, além de gerar ganhos superiores nos níveis de força quando comparado com o treino de alongamento. A combinação de ambos os tipos de treino – com resistências e alongamento na mesma sessão – não é relevante o suficiente para que se considere um método superior a sessões apenas com treino com resistências. As diretrizes do ACSM, no que concerne ao treino da flexibilidade, são incoerentes e não deverão ser seguidas. Além de não cumprirem com os pressupostos que propõem, representam um investimento temporal que melhor poderia ser aplicado com outras atividades. Aplicações práticas: Por definição e bom uso da língua portuguesa, o termo flexibilidade deverá ser substituído por melhor termo, um que expresse realmente a qualidade física que se manifesta em amplitude de movimento articular. O termo mais correto será mobilidade. É sugerida uma origem alternativa para a sua diminuída expressão, nomeadamente a falta de controlo da musculatura agonista. O autor defende o treino com resistências como método superior ao alongamento, no treino da mobilidade ativa, ganhos de força e prevenção de lesões. O cumprimento das diretrizes tradicionais de prescrição do treino com resistências, tal como apresentadas pelo ACSM, apresenta-se como suficiente para tal efeito. Contudo, recomendações mais concisas e menos generalistas são aqui descritas, ainda que sejam necessárias mais pesquisas para clarificar os parâmetros ideais (se é que existem) de construção dos exercícios para o objetivo pretendido.

Chronic Plantarflexor Stretching During Ankle Immobilization Helps Preserve Calf Girth, Plantarflexion Peak Torque, and Ankle Dorsiflexion Motion

Article

Sep 2017

Context: Chronic plantarflexor (PF) stretching during ankle immobilization helps preserve calf girth, plantarflexion peak torque, and ankle dorsiflexion (DF) motion. Immobilization can lead to decreases in muscle peak torque, muscle size, and joint ROM. Recurrent static stretching during a period of immobilization may reduce the extent of these losses. Objective: To investigate the effects of chronic static stretching on PF peak torque, calf girth, and DF range of motion (ROM) after two weeks of ankle immobilization. Design: Randomized controlled clinical trial. Setting: Athletic training facility. Participants: Thirty-six healthy college-aged (19.81±2.48) females. Interventions: Subjects were randomly assigned to one of three groups: control group, immobilized group (IM), and immobilized plus stretching group (IM+S). Each group participated in a familiarization period, a pre-test, and, two weeks later, a post-test. The IM group and IM+S group wore the Aircast FP Walker for two weeks on the left leg. During this time, the IM+S group participated in a stretching program, which consisted of two 10-minute stretching procedures each day for the 14 days. Main outcome measures: One-way ANOVA was used to determine differences in the change of ankle girth, PF peak torque, and DF ROM between groups with an α level of < 0.05. Results: A significant difference was noted between groups in girth (F2,31 =5.64, P=0.009), DF ROM (F2,31 =26.13, P<0.0001), and PF peak torque (F2,31 =7.74, P=0.002). Post-hoc testing also showed a significance difference between change in calf girth of the control group compared to the IM group (P=0.007) and a significant difference in change of peak torque in the IM+S group and the IM group (P=0.001). Also, a significant difference was shown in DF ROM between the control group and IM+S group (P=0.006), the control group and the IM group (P<0.0001), and the IM+S group and the IM group (P<0.0001). Conclusion: Chronic static stretching during two weeks of immobilization may decrease the loss of calf girth, ankle PF peak torque, and ankle DF ROM.

Influence of static stretching on hamstring flexibility in healthy young adults: Systematic review and meta-analysis

Article

Full-text available

Jul 2016

The aim of the current study was to investigate the influence of static stretching on hamstring flexibility in healthy young adults by means of systematic review and meta-analysis. The search strategy included MEDLINE, PEDro, Cochrane CENTRAL, EMBASE, LILACS, and manual search from inception to June 2015. Randomized and controlled clinical trials studies that have compared static stretching to control group, and evaluated range of motion (ROM), were included. On the other hand, studies that have worked with special population such as children, elderly people, athletes, and people with any dysfunction/disease were excluded, as well as articles that have used contralateral leg as control group or have not performed static stretching. The meta-analysis was divided according to three types of tests. Nineteen studies were included out of the 813 articles identified. In all tests, the results favored static stretching compared to control group: passive straight leg raise (12.04; 95% CI: 9.61 to 14.47), passive knee extension test (8.58; 95% CI: 6.31 to 10.84), and active knee extension test (8.35; 95% CI: 5.15 to 11.55). In conclusion, static stretching was effective in increasing hamstring flexibility in healthy young adults.

Effects of 8-week Static Stretch and PNF Training on the Angle-torque Relationship

Article

Aug 2009

This study tested the hypothesis that the extent of enhancement in muscle strength following an 8-week program of static stretch (SS) and proprioceptive neuromuscular facilitation (PNF) training would be related to a shift in optimum angle (OA) toward a longer muscle length. Thirty healthy males were randomly assigned into SS, PNF, and control (CON) groups (n = 10 per group). The SS and the PNF groups engaged in flexibility training three times per week for eight weeks, while the CON group underwent no training during this time. Passive range of motion (P-ROM) of the hip and maximal isokinetic concentric strength (ISO) at the angular velocity of 60°/s (i.e, the angle-torque relationship) were measured before and after training for all groups. The results of this study showed that compared to before training, the P-ROM values of both the SS (25°) and PNF (31°) groups were significantly increased (P < 0.05) after training, while those of the CON group remained unchanged (P > 0.05). In addition, after the training, both the SS and PNF groups saw a significant increase in ISO (SS: 13%; PNF: 17%; P < 0.05), and a marked shift of the OA toward a longer muscle length (SS: 9°; PNF: 10°; P < 0.05). The CON group, however, saw no significant change in either of these two variables. There was a positive correlation (P < 0.05) between the increase in ISO and the shift of OA toward a longer muscle length for the SS (r = .69) and PNF (r = .78) groups after training. It was concluded that eight weeks of SS and PNF training can not only effectively improve flexibility, but also increase ISO and cause a shift of OA toward a longer muscle length.

The effects of training focused on improving maximal strength and power abilities in young players of collective sports

Article

Full-text available

Sep 2014

A Review of Psychosocial Factors that Facilitate Sport Injury Rehabilitation Adherence

Article

Full-text available

Jan 2015

Many individuals experience injuries that require a period of rehabilitation. Although a thorough understanding of the necessary physical requirements for the rehabilitation is essential, it is also critical to have appropriate knowledge of the psychosocial factors that facilitate adherence. Using the integrated model of psychological response to sport injury as a guiding theoretical framework, this paper reviews the most important psychosocial aspects of rehabilitation. The factors can be classified in two categories, as either personal or situational variables. When examining personal factors, self-motivation has been found to have the strongest link with adherence, whereas self-efficacy and belief in the efficacy of the treatment have also been found to be of importance. Social support and practitioner-client communication have been identified as the two strongest situational variables related to adherence. Some limitations and future directions of sport injury research are discussed. Overall, consideration of the psychosocial aspects of injury is an integral step in providing holistic care and ensuring that the athlete is ready to return to play.

Chronic effect of the combinations of resistance exercises with static stretching exercises on flexibility levels in trained men

Article

Full-text available

Jan 2013

Effects of contract-relax stretching training on muscle performance in athletes

Article

Full-text available

Feb 1997
Eur J Appl Physiol Occup Physiol

The effects of an 8-week unilateral contract-relax (CR) stretching training program (passive stretch after isometric contraction) on muscular performance were investigated in a group of 16 athletes. The flexibility, maximum torque and angular position as well as contraction work in movements of the knee joint were determined before training and after 4 and 8 weeks of training. The torque measurements were performed under isokinetic conditions, eccentrically at angular velocities of 60 degrees x s(-1) and 120 degrees x s(-1), isometrically at five different joint positions, and concentrically at angular velocities of 60, 120, 180 and 240 degrees x s(-1) using an isokinetic dynamometer. A surface electromyogram (EMG) of the thigh muscles (quadriceps and hamstrings) was recorded simultaneously. As compared to untrained control limbs, significant improvements in active and passive flexibility (up to 6.3 degrees in range of motion), maximum torque (up to 21.6%) and work (up to 12.9%) were observed, and these were especially pronounced under eccentric load conditions. A comparison between integrated EMG recordings during eccentric and concentric loads, as well as the interpretation of the training-induced changes in the EMG, suggest that muscular activity under eccentric loads may be impaired by mental processes.

The effects of preexercise stretching on muscular soreness, tenderness and force loss following heavy eccentric exercise

Article

Full-text available

Sep 1999

The present study sought to investigate the effects of preexercise stretching on delayed onset muscle soreness (DOMS), i.e. soreness, tenderness and loss of muscle force, that usually occurs after strenuous or unaccustomed eccentric exercise. Ten female volunteers performed 10 sets of 10 maximal isokinetic eccentric contractions for knee flexion with both legs after a 5-min ergometer cycling warm-up. Prior to the exercise for one leg, randomly chosen, 4 x 20 s of static stretching for the hamstring muscle group was implemented. Rated soreness, tenderness on algometer pressure and loss of maximal eccentric contractile force was evaluated preexercise and 24, 48 and 96 h postexercise. The exercise bout produced severe DOMS, with parameters peaking and troughing at 48 h postexercise. However, no significant differences were found, regarding any of the parameters, when comparing stretched and nonstretched legs. The present study thus suggests that preexercise static stretching has no preventive effect on the muscular soreness, tenderness and force loss that follows heavy eccentric exercise.

Reduced strength after passive stretch of the human plantarflexors

Article

Full-text available

Oct 2000

The purpose of this study was to assess strength performance after an acute bout of maximally tolerable passive stretch (PS(max)) in human subjects. Ten young adults (6 men and 4 women) underwent 30 min of cyclical PS(max) (13 stretches of 135 s each over 33 min) and a similar control period (Con) of no stretch of the ankle plantarflexors. Measures of isometric strength (maximal voluntary contraction), with twitch interpolation and electromyography, and twitch characteristics were assessed before (Pre), immediately after (Post), and at 5, 15, 30, 45, and 60 min after PS(max) or Con. Compared with Pre, maximal voluntary contraction was decreased at Post (28%) and at 5 (21%), 15 (13%), 30 (12%), 45 (10%), and 60 (9%) min after PS(max) (P < 0.05). Motor unit activation and electromyogram were significantly depressed after PS(max) but had recovered by 15 min. An additional testing trial confirmed that the torque-joint angle relation may have been temporarily altered, but at Post only. These data indicate that prolonged stretching of a single muscle decreases voluntary strength for up to 1 h after the stretch as a result of impaired activation and contractile force in the early phase of deficit and by impaired contractile force throughout the entire period of deficit.

Acute effects of stretching on the neuromechanical properties of the tricep surae complex

Article

Full-text available

Mar 2002

Previous research has shown that an acute bout of passive muscle stretching can diminish performance in certain movements where success is a function of maximal force and/or power output. Two possible mechanisms that might account for such findings are a change in active musculotendinous stiffness and a depression of muscle activation. To investigate the likelihood of these two mechanisms contributing to a post-stretch reduction in performance, we examined the acute effects of stretching on the active stiffness and muscle activation of the triceps surae muscle group during maximal single-joint jumps with movement restricted to the ankle joint. Ten males performed both static (SJ) and countermovement (CMJ) jumps before and after passively stretching the triceps surae. Electrical activity of the triceps surae during each jump was determined by integrating electromyographic recordings (IEMG) over the course of the movement. Triceps surae musculotendinous stiffness was calculated before and after stretching using a technique developed by Cavagna (1970). Following stretching, a significant decrease [mean (SD) 7.4 (1.9)%; P<0.05] in jump height for the CMJ occurred, but for the SJ, no significant ( P>0.05) change in jump height was found. A small but significant decrease [2.8 (1.24)%; P<0.05] in stiffness was noted, but the magnitude of this change was probably not sufficient for it to have been a major factor underlying the decline in CMJ performance. Paradoxically, after stretching, the SJ exhibited a significant ( P<0.05) decrease in IEMG, but the IEMG for the CMJ remained unchanged ( P>0.05). It appears that an acute bout of stretching can impact negatively upon the performance of a single-joint CMJ, but it is unlikely that the mechanism responsible is a depression of muscle activation or a change in musculotendinous stiffness.

Neural and mechanical response of the triceps surae muscle group after 1 h of repeated fast passive stretches

Article

Full-text available

Jul 2004

Experiments were carried out to examine interaction between mechanical changes of the muscle-tendon unit and reduced reflex sensitivity after repeated and prolonged passive muscle stretching (RPS). There is some evidence that this interaction might be relevant also during active stretch-shortening cycle type of fatigue tasks. The results demonstrated a clear deterioration of voluntarily and electrically induced muscle contractions after RPS. Maximal voluntary contraction (MVC), average electromyographic activities of the gastrocnemius and soleus muscles, and maximal twitch contraction decreased on average by 13.8, 10.4, 7.6, and 16.8%, respectively. In addition, there was a 14% lengthening in the total duration of the twitch. MVCs measured at different ankle joint angles revealed a downward and rightward shift in the torque-fascicle length curve after RPS. Interestingly, there was a crossing in the torque-fascicle length curves while measured at different activation levels but at the same joint angle before and after RPS. Even though no changes were observed in the activation level during MVCs, all the reflex parameters showed a clear reduction after RPS. This study presents evidence that repeated and prolonged passive muscle stretching can lead to some modification of material behavior of the aponeurosis-tendon system, such as stress relaxation and/or plastic deformation. In addition, altered material properties seem to affect proprioceptive feedback and, therefore, the motor unit activation in proportion to the contractile failure.

An Acute Bout of Static Stretching: Effects on Force and Jumping Performance

Article

Full-text available

Sep 2004

The objectives of this study were to examine whether a static stretching (SS) routine decreased isometric force, muscle activation, and jump power while improving range of motion (ROM). Second, the study attempted to compare the duration of the dependent variable changes with the duration of the change in ROM. Twelve participants were tested pre- and post- (POST, 30, 60, 90, and 120 min) SS of the quadriceps and plantar flexors (PF) or a similar period of no stretch (control). Measurements during isometric contractions included maximal voluntary force (MVC), evoked contractile properties (peak twitch and tetanus), surface integrated electromyographic (iEMG) activity of the agonist and antagonistic muscle groups, and muscle inactivation as measured by the interpolated twitch technique (ITT). Vertical jump (VJ) measurements included unilateral concentric-only (no countermovement) jump height as well as drop jump height and contact time. ROM associated with seated hip flexion, prone hip extension, and plantar flexion-dorsiflexion was also recorded. After SS, there were significant overall 9.5% and 5.4% decrements in the torque or force of the quadriceps for MVC and ITT, respectively. Force remained significantly decreased for 120 min (10.4%), paralleling significant percentage increases (6%) in sit and reach ROM (120 min). After SS, there were no significant changes in jump performance or PF measures. The parallel duration of changes in ROM and quadriceps isometric force might suggest an association between stretch-induced changes in muscle compliance and isometric force output.

Acute effects of passive muscle stretching on sprint performance

Article

Full-text available

May 2005

The results of previous research have shown that passive muscle stretching can diminish the peak force output of subsequent maximal isometric, concentric and stretch-shortening contractions. The aim of this study was to establish whether the deleterious effects of passive stretching seen in laboratory settings would be manifest in a performance setting. Sixteen members (11 males, 5 females) of a Division I NCAA track athletics team performed electronically timed 20 m sprints with and without prior stretching of the legs. The experiment was done as part of each athlete's Monday work-out programme. Four different stretch protocols were used, with each protocol completed on a different day. Hence, the test period lasted 4 weeks. The four stretching protocols were no-stretch of either leg (NS), both legs stretched (BS), forward leg in the starting position stretched (FS) and rear leg in the starting position stretched (RS). Three stretching exercises (hamstring stretch, quadriceps stretch, calf stretch) were used for the BS, FS and RS protocols. Each stretching exercise was performed four times, and each time the stretch was maintained for 30 s. The BS, FS and RS protocols induced a significant (P < 0.05) increase (approximately 0.04 s) in the 20 m time. Thus, it appears that pre-event stretching might negatively impact the performance of high-power short-term exercise.

Evolution of mosaic structure in Si0.7Ge0.3 epilayers grown on Si(001) substrates

Article

Aug 1999

In this article, we report a study of mosaic structures in partially relaxed Si0.7Ge0.3 epilayers grown on Si(001) substrates by x-ray double- and triple-axis diffractometry. The samples have different layer thicknesses and hence different degrees of strain relaxation. Our results show that, at early stages of strain relaxation, the films contain mosaic regions laterally separated by perfect regions. This is because the mosaic structure caused by a misfit dislocation is effectively localized in a lateral range of the layer thickness. Therefore, far from the dislocations, the film is virtually a perfect crystal. With the increase in the degree of strain relaxation, and consequently in the dislocation density, the mosaic regions of the layer expand while the perfect regions shrink and finally vanish completely. Moreover, our results indicate that the conventional method of estimating dislocation density from the x-ray rocking curve width fails in our case. © 1999 American Institute of Physics.

A mechanism for altered flexibility in human skeletal muscle

Article

Dec 1996

1. We investigated the effect of a long-term stretching regimen on the tissue properties and stretch tolerance of human skeletal muscle. 2. Resistance to stretch was measured as torque (in N m) offered by the hamstring muscle group during passive knee extension while electromyographic (EMG) activity, knee joint angle and velocity were continuously monitored during a standardized stretch manoeuvre. Seven healthy subjects were tested before and after a 3 week training period using two separate protocols. Protocol 1 consisted of a slow stretch at 0.087 rad s-1 to a predetermined angle followed by a 90 s holding phase. Subjects were brought to the same angle before and after the training period. Protocol 2 was a similar stretch, but continued to the point of pain. 3. During protocol 1 the torque rose during the stretch and then declined during the holding phase. EMG activity was small and did not change significantly during the protocol. No significant differences in stiffness, energy and peak torque about the knee joint were seen as a result of the training. During protocol 2 the angle to which the knee could be extended was significantly increased as a result of the training. This was accompanied by a comparable increase in peak torque and energy. EMG activity was small and not affected by training. 4. It is concluded that reflex EMG activity does not limit the range of movement during slow stretches and that the increased range of motion achieved from training is a consequence of increased stretch tolerance on the part of the subject rather than a change in the mechanical or viscoelastic properties of the muscle.

Viscoelastic characteristics of muscle: Passive stretching versus muscular contractions

Article

Jan 1998

This study compared the effects of repeated contractions and repeated passive stretches on the viscoelastic properties of muscle. The tibialis anterior (TA) muscles of eight anesthetized male New Zealand white rabbits were studied. In each rabbit, one hindlimb was randomly assigned to the repeated muscular contraction group (CON) and the contralateral hindlimb to the repeated passive stretch group (STRETCH). The passive tension at neutral length was measured in all muscles before and after both repeated muscular contractions or repeated passive stretches. In the CON hindlimb, the peroneal nerve was stimulated with a nerve stimulator for 1 s, and the resulting contractile force was measured. Stimulations were repeated every 10 s for a total of 10 contractions. In the STRETCH hindlimb, the TA was stretched from its shortest in vivo length to its maximum in vivo length 10 times at 20 cm x min-1. The maximum force generated during the first contraction in the CON group averaged 21.74 +/- 1.41 N, with a subsequent reduction with each muscle contraction to 13.66 +/- 0.81 N by the tenth contraction. The average peak tensile force in the STRETCH group was 17.39 +/- 2.61 N for the first passive stretch, decreasing to 13.57 +/- 1.84 by the tenth stretch. After repeated muscular contractions in the CON hindlimbs, the passive tension at neutral length decreased from 0.88 +/- 0.22 N to 0.42 +/- 0.08 N. After repeated passive stretches in the STRETCH hindlimbs, the passive tension at neutral length decreased from 1.16 +/- 0.17 N to 0.67 +/- 0.09 N. The percentage decreases in passive tension between the CON and STRETCH groups were not statistically significant (P = 0.24). The results show that stretching and contracting both result in tissue relaxation of the muscle-tendon unit. This finding may be a result of changes in the viscous elements of the connective tissue secondary to the forces generated by either stretches or contractions. This study suggests that well controlled isometric muscular contractions may result in decreased passive tension in a muscle at neutral length, a finding that one normally associates with passive stretching.

Passive properties of human skeletal muscle during stretch maneuvers. A review

Article

May 1998

Stig Peter Magnusson

Despite limited scientific knowledge, stretching of human skeletal muscle to improve flexibility is a widespread practice among athletes. This article reviews recent findings regarding passive properties of the hamstring muscle group during stretch based on a model that was developed which could synchronously and continuously measure passive hamstring resistance and electromyographic activity, while the velocity and angle of stretch was controlled. Resistance to stretch was defined as passive torque (Nm) offered by the hamstring muscle group during passive knee extension using an isokinetic dynamometer with a modified thigh pad. To simulate a clinical static stretch, the knee was passively extended to a pre-determined final position (0.0875 rad/s, dynamic phase) where it remained stationary for 90 s (static phase). Alternatively, the knee was extended to the point of discomfort (stretch tolerance). From the torque-angle curve of the dynamic phase of the static stretch, and in the stretch tolerance protocol, passive energy and stiffness were calculated. Torque decline in the static phase was considered to represent viscoelastic stress relaxation. Using the model, studies were conducted which demonstrated that a single static stretch resulted in a 30% viscoelastic stress relaxation. With repeated stretches muscle stiffness declined, but returned to baseline values within 1 h. Long-term stretching (3 weeks) increased joint range of motion as a result of a change in stretch tolerance rather than in the passive properties. Strength training resulted in increased muscle stiffness, which was unaffected by daily stretching. The effectiveness of different stretching techniques was attributed to a change in stretch tolerance rather than passive properties. Inflexible and older subjects have increased muscle stiffness, but a lower stretch tolerance compared to subjects with normal flexibility and younger subjects, respectively. Although far from all questions regarding the passive properties of humans skeletal muscle have been answered in these studies, the measurement technique permitted some initial important examinations of vicoelastic behavior of human skeletal muscle.

The effect of passive stretching on delayed onset muscle soreness, and other detrimental effects following eccentric exercise

Article

Aug 1998

The aim of this study was to measure if passive stretching would influence delayed onset muscle soreness (DOMS), dynamic muscle strength, plasma creatine kinase concentration (CK) and the ratio of phosphocreatine to inorganic phosphate (PCr/P(i)) following eccentric exercise. Seven healthy untrained women, 28-46 years old, performed eccentric exercise with the right m. quadriceps in an isokinetic dynamometer (Biodex, angle velocity: 60 degrees.s-1) until exhaustion, in two different experiments, with an interval of 13-23 months. In both experiments the PCr/P(i) ratio, dynamic muscle strength, CK and muscle pain were measured before the eccentric exercise (day 0) and the following 7 d. In the second experiment daily passive stretching (3 times of 30 s duration, with a pause of 30 s in between) of m. quadriceps was included in the protocol. The stretching was performed before and immediately after the eccentric exercise at day 0, and before measurements of the dependent variables daily for the following 7 d. The eccentric exercise alone led to significant decreases in PCr/P(i) ratio (P < 0.001) and muscle strength (P < 0.001), and an increase in CK concentration (P < 0.01). All subjects reported pain in the right m. quadriceps with a peak 48 h after exercise. There was no difference in the reported variables between experiments one and two. It is concluded that passive stretching did not have any significant influence on increased plasma-CK, muscle pain, muscle strength and the PCr/P(i) ratio, indicating that passive stretching after eccentric exercise cannot prevent secondary pathological alterations.

Increasing Hamstring Flexibility Decreases Lower Extremity Overuse Injuries in Military Basic Trainees

Article

Mar 1999
AM J SPORT MED

The purpose of this intervention study was to prove that increasing flexibility of the hamstring musculotendinous unit would decrease the number of lower extremity overuse injuries that occur in military infantry basic trainees. Two different companies going through basic training at the same time were used. Hamstring flexibility was checked at the beginning and at the end of the 13-week infantry basic training course. The control company (N = 148) proceeded through normal basic training. The intervention company (N = 150) followed the same program but added three hamstring stretching sessions to their already scheduled fitness program. All subsequent lower extremity overuse injuries were recorded through the troop medical clinic. Hamstring flexibility increased significantly in the intervention group compared with the control group. The number of injuries was also significantly lower in the intervention group. Forty-three injuries occurred in the control group for an incidence rate of 29.1%, compared with 25 injuries in the intervention group for an incidence rate of 16.7%. Thus, in this study, the number of lower extremity overuse injuries was significantly lower infantry basic trainees with increased hamstring flexibility.

Reduced reflex sensitivity persists several days after long-lasting stretch-shortening cycle exercise

Article

Apr 1999

The mechanisms related to the acute and delayed secondary impairment of the stretch reflex function were investigated after long-lasting stretch-shortening cycle exercise. The results demonstrated a clear deterioration in muscle function immediately after fatigue, which was accompanied by a clear reduction in active and passive reflex sensitivity. For active and passive stretch reflexes, this reduction was biphasic (P < 0.05 to P < 0.001). However, for the ratio of the electrically induced maximal Hoffmann reflex to the maximal mass compound action potential, only one significant reduction was seen immediately after fatigue (71.2%, P < 0.01). A similar significant (P < 0.01) decrease in the stretch-resisting force of the muscle was also detected. Clear increases were found in the indirect markers of muscle damage (serum creatine kinese activity and skeletal troponin I), which could imply the occurrence of ultrastructural muscle damage. It is suggested that the acute reduction in reflex sensitivity is of reflex origin and due to two active mechanisms, disfacilitation and presynaptic inhibition. However, the delayed second decline in the sensitivity of some reflex parameters may be attributable to the secondary injury, because of some inflammatory response to the muscle damage. This might emphasize the role of presynaptic inhibition via group III and IV muscle afferents.

Altered reflex sensitivity after repeated and prolonged muscle stretching

Article

Apr 1999

Experiments were carried out to test the effect of prolonged and repeated passive stretching (RPS) of the triceps surae muscle on reflex sensitivity. The results demonstrated a clear deterioration of muscle function immediately after RPS. Maximal voluntary contraction, average electromyographic activity of the gastrocnemius and soleus muscles, and zero crossing rate of the soleus muscle (recorded from 50% maximal voluntary contraction) decreased on average by 23.2, 19.9, 16.5, and 12.2%, respectively. These changes were associated with a clear immediate reduction in the reflex sensitivity; stretch reflex peak-to-peak amplitude decreased by 84. 8%, and the ratio of the electrically induced maximal Hoffmann reflex to the maximal mass compound action potential decreased by 43. 8%. Interestingly, a significant (P < 0.01) reduction in the stretch-resisting force of the measured muscles was observed. Serum creatine kinase activity stayed unaltered. This study presents evidence that the mechanism that decreases the sensitivity of short-latency reflexes can be activated because of RPS. The origin of this system seems to be a reduction in the activity of the large-diameter afferents, resulting from the reduced sensitivity of the muscle spindles to repeated stretch.

A randomized trial of preexercise stretching for prevention of lower-limb injury

Article

Feb 2000

This study investigated the effect of muscle stretching during warm-up on the risk of exercise-related injury. 1538 male army recruits were randomly allocated to stretch or control groups. During the ensuing 12 wk of training, both groups performed active warm-up exercises before physical training sessions. In addition, the stretch group performed one 20-s static stretch under supervision for each of six major leg muscle groups during every warm-up. The control group did not stretch. 333 lower-limb injuries were recorded during the training period, including 214 soft-tissue injuries. There were 158 injuries in the stretch group and 175 in the control group. There was no significant effect of preexercise stretching on all-injuries risk (hazard ratio [HR] = 0.95, 95% CI 0.77-1.18), soft-tissue injury risk (HR = 0.83, 95% CI 0.63-1.09), or bone injury risk (HR = 1.22, 95% CI 0.86-1.76). Fitness (20-m progressive shuttle run test score), age, and enlistment date all significantly predicted injury risk (P < 0.01 for each), but height, weight, and body mass index did not. A typical muscle stretching protocol performed during preexercise warm-ups does not produce clinically meaningful reductions in risk of exercise-related injury in army recruits. Fitness may be an important, modifiable risk factor.

Flexibility and passive resistance of hamstrings of young adults using two different static stretching protocols

Article

Apr 2001

This investigation determined the effects of a static stretching program with different stretching protocols on the flexibility and passive resistance of the hamstrings of young adults. Forty healthy subjects (24 males and 16 females) aged 18 to 30 years were randomly assigned to one of four groups. The two training groups underwent static stretch training of the hamstrings either with a four-week protocol or with an eight-week protocol. The other two groups acted as control groups. A significant increase in flexibility of hamstrings was found in both of the two training groups (P<0.05). No difference was found in the range of motion gained between the two training groups. An increase in passive resistance at the corresponding maximal joint angle was only demonstrated in the four-week training group (P<0.05). Both protocols are effective in terms of improving flexibility of hamstrings. However, if injury is reduced when there is relatively lower passive resistance at the end-of-range, then the eight-week training regimen would be recommended.

Changes in passive tension of muscle in humans and animals after eccentric exercise

Article

Jul 2001

This is a report of experiments on ankle extensor muscles of human subjects and a parallel series on the medial gastrocnemius of the anaesthetised cat, investigating the origin of the rise in passive tension after a period of eccentric exercise. Subjects exercised their triceps surae of one leg eccentrically by walking backwards on an inclined, forward‐moving treadmill. Concentric exercise required walking forwards on a backwards‐moving treadmill. For all subjects the other leg acted as a control. Immediately after both eccentric and concentric exercise there was a significant drop in peak active torque, but only after eccentric exercise was this accompanied by a shift in optimum angle for torque generation and a rise in passive torque. In the eccentrically exercised group some swelling and soreness developed but not until 24 h post‐exercise. In the animal experiments the contracting muscle was stretched by 6 mm at 50 mm s ⁻¹ over a length range symmetrical about the optimum length for tension generation. Measurements of passive tension were made before and after the eccentric contractions, using small stretches to a range of muscle lengths, or with large stretches covering the full physiological range. After 150 eccentric contractions, passive tension was significantly elevated over most of the range of lengths. Measurements of work absorption during stretch‐release cycles showed significant increases after the contractions. It is suggested that the rise in passive tension in both human and animal muscles after eccentric contractions is the result of development of injury contractures in damaged muscle fibres.

Leg stiffness and mechanical energetic processes during jumping on a sprung surface

Article

Jul 2001

The purposes of this study were: a) to examine the effect of verbal instructions given to the subjects on the control of lower extremity stiffness and b) to determine the effect of leg stiffness on mechanical energetic processes during drop jumps on a sprung surface. A total of 10 female athletes performed a series of drop jumps on a sprung surface from heights of 20 and 40 cm. The instructions given to the subjects were a) "jump as high as you can" and b) "jump high a little faster than at your previous jump." The jumps were performed at each height until the athlete could not achieve a shorter ground contact time. Four jumps per subject per height were analyzed. The ground reaction forces were measured using a "Kistler" force plate (1000 Hz). The athletes' body positions were recorded using a high-speed (250 Hz) video camera. The deformation of the sprung surface was determined by another high-speed camera operating at 500 Hz. Surface EMG was used to measure muscle activity in five leg muscles. The contact time showed high correlation with leg stiffness as well as with ankle and knee stiffness. The change in leg stiffness was not due to the duration of the preactivation but rather to the level of activation during this phase. An increase in leg stiffness caused an increase in the energy stored and recovered in and by the sprung surface and a decrease of the energy produced by the subjects. By influencing contact time through verbal instructions, it is possible to control leg stiffness. Maximal vertical take-off velocity of the center of mass and maximal take-off body energy can be achieved having different levels of leg stiffness. The maximization of mechanical power is achieved by optimal leg stiffness values and leg muscle preactivation levels.

Effect of Warm-Up and Flexibility Treatments on Vertical Jump Performance

Article

Sep 2001

Although different warm-up and flexibility routines are often prescribed before physical activity, little research has been conducted to determine what effects these routines have on athletic performance in activities. The purpose of this investigation was to determine to what degree different warm-up routines affect performance in the vertical jump test. The 40 female participants were asked to perform a general warm-up only, a general warm-up and static stretching, and a general warm-up and proprioceptive neuromuscular facilitation (PNF) on 3 nonconsecutive days. Each of the treatments was followed by a vertical jump test. A 1-way repeated-measures analysis of variance revealed a significant difference in vertical jump performance. A post hoc analysis revealed decreased vertical jump performances for the PNF treatment group. Based on the results of this study, performing PNF before a vertical jump test would be detrimental to performance.

Effects of stretching before and after exercising on muscle soreness and risk of injury: Systematic review

Article

Sep 2002
Br Med J

To determine the effects of stretching before and after exercising on muscle soreness after exercise, risk of injury, and athletic performance. Systematic review. Randomised or quasi-randomised studies identified by searching Medline, Embase, CINAHL, SPORTDiscus, and PEDro, and by recursive checking of bibliographies. Muscle soreness, incidence of injury, athletic performance. Five studies, all of moderate quality, reported sufficient data on the effects of stretching on muscle soreness to be included in the analysis. Outcomes seemed homogeneous. Stretching produced small and statistically non-significant reductions in muscle soreness. The pooled estimate of reduction in muscle soreness 24 hours after exercising was only 0.9 mm on a 100 mm scale (95% confidence interval -2.6 mm to 4.4 mm). Data from two studies on army recruits in military training show that muscle stretching before exercising does not produce useful reductions in injury risk (pooled hazard ratio 0.95, 0.78 to 1.16). Stretching before or after exercising does not confer protection from muscle soreness. Stretching before exercising does not seem to confer a practically useful reduction in the risk of injury, but the generality of this finding needs testing. Insufficient research has been done with which to determine the effects of stretching on sporting performance.

Effect of static stretching on neural and mechanical properties of the human plantar–flexor muscles

Article

Feb 2004

To determine the contributions of neural and mechanical mechanisms to the limits in the range of motion (ROM) about a joint, we studied the effects of 30 sessions of static stretch training on the characteristics of the plantar-flexor muscles in 12 subjects. Changes in the maximal ankle dorsiflexion and the torque produced during passive stretching at various ankle angles, as well as maximal voluntary contraction (MVC) and electrically induced contractions, were recorded after 10, 20, and 30 sessions, and 1 month after the end of the training program. Reflex activities were tested by recording the Hoffmann reflex (H reflex) and tendon reflex (T reflex) in the soleus muscle. Training caused a 30.8% (P < 0.01) increase in the maximal ankle dorsiflexion. This improved flexibility was associated (r(2) = 0.88; P < 0.001) with a decrease in muscle passive stiffness and, after the first 10 sessions only, with a small increase in passive torque at maximal dorsiflexion. Furthermore, both the H- and T-reflex amplitudes were reduced after training, especially the latter (-36% vs. -14%; P < 0.05). The MVC torque and the maximal rate of torque development were not affected by training. Although the changes in flexibility and passive stiffness were partially maintained 1 month after the end of the training program, reflex activities had already returned to control levels. It is concluded that the increased flexibility results mainly from reduced passive stiffness of the muscle-tendon unit and tonic reflex activity. The underlying neural and mechanical adaptation mechanisms, however, showed different time courses.

Does Stretching Improve Performance?

Article

Oct 2004
CLIN J SPORT MED

Ian Shrier

The purpose of this article was to evaluate the clinical and basic science evidence surrounding the hypothesis that stretching improves performance. MEDLINE and Sport Discus were searched using MeSH and textwords for English-language and French-language articles related to stretching and performance (or performance tests). Additional references were reviewed from the bibliographies and from citation searches on key articles. All articles related to stretching and performance (or performance tests) were reviewed. Of the 23 articles examining the effects of an acute bout of stretching, 22 articles suggested that there was no benefit for the outcomes isometric force, isokinetic torque, or jumping height. There was 1 article that suggested improved running economy. Of 4 articles examining running speed, 1 suggested that stretching was beneficial, 1 suggested that it was detrimental, and 2 had equivocal results. Of the 9 studies examining the effects of regular stretching, 7 suggested that it was beneficial, and the 2 showing no effect examined only the performance test of running economy. There were none that suggested that it was detrimental. An acute bout of stretching does not improve force or jump height, and the results for running speed are contradictory. Regular stretching improves force, jump height, and speed, although there is no evidence that it improves running economy.

Acute passive stretching alters the mechanical properties of human plantar flexors and optimal angle for maximal voluntary contraction

Article

Apr 2005

The purpose of this study was to investigate whether acute passive stretching (APS) reduced maximal isometric voluntary contraction (MVC) of the plantar flexors (PF) and if so, by what mechanisms. The PF in 15 female volunteers were stretched for 10 min (5×120 s) by a torque motor to within 2° of maximum dorsiflexion (D) range of motion (ROM). MVC with twitch interpolation, maximal Hoffmann reflex (H max) and compound action potentials (M max) were recorded at 20° D. Stretch reflexes (SR) were mechanically induced at 200° s−1 between 0° and 10°D and SR torque and EMG amplitude were determined. All tests were assessed pre- (pre) and post-APS (post-test1). MVC, SR, and M max were again assessed after additional stretch was applied [mean 26 (1)° D; post-test2] to test if the optimal angle had been altered. EMG was recorded from soleus (SOL), medial gastrocnemius (MG) and tibialis anterior (TA) using bipolar surface electrodes. APS resulted in a 27% decrease in mean peak passive torque (P<0.05). MVC and SR torque were 7% (P<0.05) and 13% lower at post-test1 (P<0.05), respectively. SR EMG amplitude of SOL and MG was reduced by 27% (P<0.05) and 22% (P<0.05), respectively. The H max/M max EMG and H max/M max torque ratios were unchanged at post-test1. At post-test2, MVC and SR EMG recovered to pre-APS values, while the SR and M max torque increased by 19% and 13%, respectively (P<0.05). The decrease in MVC during post-test1 was attributed to changes in the mechanical properties of PF and not to reduced muscle activation.

The acute effects of static stretching on peak torque, mean power output, electromyography, and mechanomyography

Article

Mar 2005

The purpose of this study was to examine the acute effects of static stretching on peak torque (PT), the joint angle at PT, mean power output (MP), electromyographic (EMG) amplitude, and mechanomyographic (MMG) amplitude of the vastus lateralis (VL) and rectus femoris (RF) muscles during maximal, voluntary concentric isokinetic leg extensions at 60 and 240 degrees x s(-1) of the stretched and unstretched limbs. Twenty-one volunteers [mean age (SD) 21.5 (1.3) years] performed maximal, voluntary concentric isokinetic leg extensions for the dominant and non-dominant limbs at 60 and 240 degrees x s(-1). Surface EMG (muVrms) and MMG (mVrms) signals were recorded from the VL and RF muscles during the isokinetic tests. PT (Nm), the joint angle at PT, and MP (W) were calculated by a dynamometer. Following the initial isokinetic tests, the dominant leg extensors were stretched using four static stretching exercises. After the stretching, the isokinetic tests were repeated. PT decreased (P< or =0.05) from pre- to post-stretching for the stretched limb at 60 and 240 degrees x s(-1) and for the unstretched limb at 60 degrees x s(-1). EMG amplitude of the VL and RF also decreased (P< or =0.05) from pre- to post-stretching for the stretched and unstretched limbs. There were no stretching-induced changes (P>0.05) for the joint angle at PT, MP, or MMG amplitude. These findings indicated stretching-induced decreases in force production and muscle activation. The decreases in PT and EMG amplitude for the unstretched limb suggested that the stretching-induced decreases may be due to a central nervous system inhibitory mechanism.

Muscle performance during maximal isometric and dynamic contractions is influenced by the stiffness of the tendinous structures

Article

Sep 2005

Contractile force is transmitted to the skeleton through tendons and aponeuroses, and, although it is appreciated that the mechanocharacteristics of these tissues play an important role for movement performance with respect to energy storage, the association between tendon mechanical properties and the contractile muscle output during high-force movement tasks remains elusive. The purpose of the study was to investigate the relation between the mechanical properties of the connective tissue and muscle performance in maximal isometric and dynamic muscle actions. Sixteen trained men participated in the study. The mechanical properties of the vastus lateralis tendon-aponeurosis complex were assessed by ultrasonography. Maximal isometric knee extensor force and rate of torque development (RTD) were determined. Dynamic performance was assessed by maximal squat jumps and countermovement jumps on a force plate. From the vertical ground reaction force, maximal jump height, jump power, and force-/velocity-related determinants of jump performance were obtained. RTD was positively related to the stiffness of the tendinous structures (r = 0.55, P < 0.05), indicating that tendon mechanical properties may account for up to 30% of the variance in RTD. A correlation was observed between stiffness and maximal jump height in squat jumps and countermovement jumps (r = 0.64, P < 0.05 and r = 0.55, P < 0.05). Power, force, and velocity parameters obtained during the jumps were significantly correlated to tendon stiffness. These data indicate that muscle output in high-force isometric and dynamic muscle actions is positively related to the stiffness of the tendinous structures, possibly by means of a more effective force transmission from the contractile elements to the bone.

Surface Electromyographic Assessment of the Effect of Static Stretching of the Gastrocnemius on Vertical Jump Performance

Article

Aug 2005

The purpose of this study was to investigate the effects of static stretching of the gastrocnemius muscle on maximal vertical jump performance using electromyographic activity (EMG) of the gastrocnemius musculature to record muscle activation during vertical jump performance. Fourteen healthy adults (8 men and 6 women) aged 18-34 years, who were familiar with the vertical jumping task and had no lower extremity injuries or any bone or joint disorders within the past year, served as participants for this study. After a brief warm-up, participants performed the following sequence: (a) three baseline maximal vertical jump trials, (b) 15 minutes of quiet sitting and three 30-second bilateral static stretches of the gastrocnemius muscles, and (c) 3 maximal vertical jump trials. Jump height data were collected using the Kistler force plate, while muscle activity was recorded during the jumping and stretching trials using a Noraxon telemetry EMG unit. Vertical jump height data as well as EMG values were averaged for the 3 trials and analyzed using paired t-tests for pre- and poststretching (alpha = 0.05). Vertical jump height was 5.6% lower when poststretch heights were compared with prestretch heights (t = -4.930, p < 0.005). Gastrocnemius EMG was 17.9% greater when the EMG during poststretch jumps was compared with prestretch jumps (t = 2.805, p < 0.02). The results from this study imply that, despite increased gastrocnemius muscle activity, static stretching of the gastrocnemius muscles had a negative effect on maximal jumping performance. The practical importance concerns coaches and athletes, who may want to consider the potential adverse effects of performing static stretching of the gastrocnemius muscles only before a jumping event, as jump height may be negatively affected. Future research is required to identify the mechanisms that affect vertical jump performance.

Effects of Stretching on Passive Muscle Tension and Response to Eccentric Exercise

Article

Jul 2006
AM J SPORT MED

Stretching is used in an attempt to improve performance and reduce the risk of muscle injury, with little evidence to support its effectiveness. Four weeks of static or ballistic stretching can attenuate the increased soreness and decreased flexibility seen after eccentric exercise. Controlled laboratory study. Twenty-nine male subjects were randomly assigned to a static stretching, ballistic stretching, or control group. On each of 4 consecutive days, they completed 4 maximal range of motion stretches using a Cybex isokinetic dynamometer to passively stretch the hamstrings at 0.087 rad.s(-1) (5 deg.s(-1)). Stiffness from 0.87 to 1.48 rad (50 degrees -85 degrees ), peak range of motion, work absorption, peak resistive torque, and soreness were measured. Participants then completed 4 weeks of either static or ballistic stretching for a total stretching duration of 3600 seconds. After training, the 4 days of testing were repeated with an eccentric exercise task added after day 1. Stretching groups had an increase in range of motion and stretch tolerance after 4 weeks of stretching, with no change in muscle stiffness, work absorption, or delayed onset muscle soreness. After eccentric exercise, they also had greater range of motion and stretch tolerance than did controls. Both static stretching and ballistic stretching increase range of motion, most likely as a result of enhanced stretch tolerance rather than changes in muscle elasticity. Four weeks of stretching maintain range of motion and stretch tolerance in the days after eccentric exercise.

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Jan 2005
449

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Jan 1999
594

Does stretching improve performance? A systematic and critical review of the literature.

Jan 2004
267

Shrier

Chronic Stretching and Voluntary Muscle Force

Abstract

No full-text available

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