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Early-Phase Resistance Training Strength Gains in Novice Lifters Are Enhanced by Doing Static Stretching
Abstract
This study investigated differences in lower-body strength improvements when using standard progressive resistance training (WT) vs. the same progressive resistance training combined with static stretching exercises (WT + ST). Thirty-two college students (16 women and 16 men) were pair matched according to sex and knee extension 1 repetition maximum (1RM). One person from each pair was randomly assigned to WT and the other to WT + ST. WT did 3 sets of 6 repetitions of knee extension, knee flexion, and leg press 3 days per week for 8 weeks with weekly increases in the weight lifted. The WT + ST group performed the same lifting program as the WT group along with static stretching exercises designed to stretch the hip, thigh, and calf muscle groups. Stretching exercise sessions were done twice a week for 30 minutes during the 8-week period. WT significantly (p < 0.05) improved their knee flexion, knee extension, and leg press 1RM by 12, 14, and 9%, respectively. WT + ST, on the other hand, significantly (p < 0.05) improved their knee flexion, knee extension, and leg press 1RM by 16, 27, and 31, respectively. In addition, the WT + ST group had significantly greater knee extension and leg press gains (p < 0.05) than the WT group. Based on results of this study, it is recommended that to maximize strength gains in the early phase of training, novice lifters should include static stretching exercises to their resistance training programs.
... In contrast to the acute effects, performing stretching exercises over a long period (chronic effect) seems to cause significant increases in strength performance. For example, Kokkonen et al. (18) observed increases of up to 31% in the 1RM test performance after an 8-week static stretching program comparing strength training in isolation and combined with static stretching exercises for the musculature of the hip, thigh, and plantar flexors. Ress et al. (33) and LaRoche et al. (20) observed increases in isometric test performance for plantar flexors and peak torque, respectively, when the tests were conducted after training with only stretching exercises for 4 weeks. ...
... Kokkonen et al. (18) conducted research to verify the differences in lower limb strength gains in physically active individuals, comparing strength training in isolation and combined with static stretching exercises for the hip and thigh muscles and plantar flexors. They found significant strength increases in the lower limbs for both groups. ...
... However, the greatest differences were observed in the group that performed strength training in combination with stretching exercises (16, 27, and 31% in the 1RM test for knee flexion, knee extension, and leg press exercises, respectively). The data from our study showed an increase of 21.97% in the knee extension exercise in the SBST group, corroborating with Kokkonen et al. (18). However, in this study the largest increases in strength could be observed in OST group, where increases of 26.56, 33.42, and 33.79% in the 1RM test for the LC, LE, and leg press exercises was verified. ...
Improving the process of how physical performance is enhanced is one of the main topics evaluated by physiologists. This process often involves athletes as well as non-athletic populations. The purpose of this study was to assess the chronic response to ten weeks of static stretching exercises carried out before and during a strength training program for eight exercises on eight repetition maximum (8RM) test performance, and basal serum IGF-1 levels. Thirty recreationally trained volunteers were randomly assigned into one of three training groups: 1) SBST (performed a warm-up with a static stretching protocol before each strength training session); 2) SDST (before each training set, a static stretching exercise was performed); and 3) OST (entire session was performed without any type of stretching exercise). Strength and IGF-1 levels were collected at the beginning (pre-test) and end (post-test) of the entire experimental procedure. All exercises showed a significant increase in muscle strength for the OST group. However, the results revealed a significant increase in muscle strength for only a few exercises in the SBST (LP, LE) and SDST (LP) experimental conditions. Significant statistical differences were found between SBST and SDST for all exercises in the OST experimental condition. Furthermore, IGF-1 expression showed no significant differences in intragroup analysis. However, the OST group showed higher values (p<0.05) in post-test when compared to other groups (increased significantly only in the OST experimental condition). It has been concluded that, while all groups showed an increase in muscular strength, but the strength training performed without any type of stretching exercise, regardless of if the stretching is performed prior or during the lifting session, can more effectively increase muscle strength as well as basal serum IGF-1 levels. It was concluded that strength training, with or without the use of stretching exercises, increased muscular strength in the studied groups, and can induce an increase in IGF-1 levels.
... Stretching exercises, in turn, are considered effective methods for improving joint range of motion (2,8,14,17), muscle strength (14,17,40), and gait speed (27). Additionally, both static stretching (SS) and dynamic stretching (DS) are generally incorporated into warm-up routines or even performed within or immediately after resistance exercise training (5,7,18,23). The SS exercises consist of holding at stretch position by actively contracting the muscles in opposition to the muscle being stretched, whereas the DS is performed by moving their limb continuously through a challenging range of motion (23). ...
... Thus, the SS stimulus time and intensity could account for the different results from these studies. This statement is based on a study that reported that resistance training combined with 30 minutes of SS exercises performed on separated days led to greater strength gains when compared with a group that performed only resistance training (18). ...
Ferreira-Júnior, JB, Benine, RPC, Chaves, SFN, Borba, DA, Martins-Costa, HC, Freitas, EDS, Bemben, MG, Vieira, CA, and Bottaro, M. Effects of static and dynamic stretching performed before resistance training on muscle adaptations in untrained men. J Strength Cond Res XX(X): 000-000, 2019-This study evaluated the effects of dynamic and static stretching (SS) performed before resistance training on biceps femoris hypertrophy and knee flexor strength gains in untrained young men. Forty-five untrained young men (age, 21.2 ± 0.5 years; mass, 72.2 ± 5.6 kg; height, 178 ± 1 cm) were randomly assigned to 1 of the 3 groups: (a) 80 seconds of SS (n = 14); (b) 80 seconds of dynamic stretching (DS, n = 13); or (c) control group (CON, n = 18) in which subjects performed no stretching before exercise. Both SS and DS were performed before resistance exercise. Resistance training consisted of 4 sets of 8-12 repetition maximum of seated leg curl exercise 2 days per week for 8 weeks, with a period of at least 48 hours between sessions. Unilateral biceps femoris muscle thickness (MT) and maximal isometric strength (MIS) of the knee flexors were measured 1 week before training and 1 week after the last training session. There were significant increases in MIS (SS = 13.9 ± 10.3 kgf; DS = 10.2 ± 13.1 kgf; CON = 12.7 ± 7.6 kgf; p < 0.05) and MT (SS = 6.0 ± 3.5 mm; DS = 6.7 ± 4.1 mm; CON = 5.7 ± 3.0 mm; p < 0.05) with no significant differences across groups (p > 0.05). Additionally, all groups demonstrated moderate effect sizes for MIS (1.27-1.4), and DS was the only group that had a large effect size for MT increases (DS = 2.18; SS = 1.35; CON = 0.92). In conclusion, 80 seconds of SS and DS did not induce any additional muscular adaptations to resistance training in untrained young men.
... Stretching exercises, in turn, are considered effective methods for improving joint range of motion (2,8,14,17), muscle strength (14,17,40), and gait speed (27). Additionally, both static stretching (SS) and dynamic stretching (DS) are generally incorporated into warm-up routines or even performed within or immediately after resistance exercise training (5,7,18,23). The SS exercises consist of holding at stretch position by actively contracting the muscles in opposition to the muscle being stretched, whereas the DS is performed by moving their limb continuously through a challenging range of motion (23). ...
... Thus, the SS stimulus time and intensity could account for the different results from these studies. This statement is based on a study that reported that resistance training combined with 30 minutes of SS exercises performed on separated days led to greater strength gains when compared with a group that performed only resistance training (18). ...
... Kokkonen et al. 28 evaluated the effects of the combination of resistive exercise with stretching on muscle strength of young subjects, beginners in strength training. The exercise protocol was performed on alternate days, i.e., the day on which the strength training was performed, the stretching was not performed, and vice versa. ...
... These authors found an increase in the muscle strength of subjects who performed strength and stretching training, when compared with subjects who performed only the strength training. The researchers suggested that strength gains could be related to morphological changes, resulting from an increase in protein synthesis, in muscle length, in the serial sarcomere number and cross-sectional area of muscle fibers 8,28 . ...
This study analyzed the effects of resistive exercise and/or stretching in the muscle morphology of ovariectomized rats. Seventy-five female Wistar rats (218±22g) were divided into 8 groups: Control (CONTROL, n=5); Ovariectomy/Hysterectomy (OH, n=10): ovariectomized/hysterectomized and then waited 8 weeks for the onset of osteopenia. Stretching (STRET, n=10): manual stretching of the soleus muscle (10 repetitions of 60s), twice weekly; Ovariectomy/Hysterectomy and Stretching (OH+STRET, n=10); Progressive Loading (PL, n=10): 4 sets of 10 repetitions, initial load 50% of body weight, increasing weekly until 70%, three times a week. Progressive Loading and Stretching (PL+STRET, n=10); Ovariectomy/Hysterectomy and Progressive loading exercise (OH+PL, n=10); Ovariectomy/Hysterectomy, Progressive Loading and Stretching (OH+PL+STRET, n=10). Stretching and/or progressive loading were performed for 6 weeks. After 14 weeks, the female rats were euthanized to remove the soleus muscle. The following variables were assessed: body weight; muscle weight and length; number and length of sarcomeres and the muscle fiber cross-sectional area (MFCSA). Comparisons between the groups were performed with ANOVA one-way post hoc Tukey or Kruskall-Wallis (p<0.05). The body and muscle weights of ovariectomized rats submitted to exercise were higher than the intact ones. The OH and OH+PL+STRET increased the muscle length and the serial sarcomere number. OH presented the smallest MFCSA compared to all groups. Ovariectomy/hysterectomy induced sarcopenia, but the exercise's protocols were enough to prevent the loss of MFCSA. The increase in body weight associated to resistive training and stretching enhanced sarcomerogenesis of ovariectomized rats.
... If Zhou's (16) conjecture that afferent input is a key to crosstraining is correct, then long-term regimens of static passive stretching should also induce strength gains in a contralateral nonstretched limb. Not only does the passive stretching of a muscle activate muscle afferents without activating the motor neurons (9,13) but passive stretching can also cause increases in the strength of the stretched muscle (10,11,15). Moreover, Smith (14) has shown that when sudden stretches are applied to the contraction during a static training session, crosstraining effect is greater than that seen with static training alone. ...
... Zhou (16) makes this suggestion based upon studies that showed EMS inducing greater crosstraining strength gains via the ability of EMS to modulate afferent nerve activity. Because passive stretching of a muscle can increase strength (10,11,15) without activating the motor neurons, and can activate afferent activity (9,13), it appeared that a long-term passive stretching program would induce the crosstraining effect. ...
It was questioned whether a unilateral stretching program would induce a crosstraining effect in the contralateral muscle. To test this, 13 untrained individuals participated in a 10-week stretching program while 12 other untrained individuals served as a control group. For the experimental group, the right calf muscle was stretched 4 times for 30 seconds, with a 30-second rest between stretches, 3 d·wk(-1) for 10 weeks. Strength, determined via 1 repetition maximum (1RM) unilateral standing toe raise, and range of motion (ROM) were measured pre-post. In the treatment group, the stretched calf muscle had a significant (p < 0.05) 8% increase in ROM, whereas the nonstretched calf muscle had a significant 1% decrease in ROM. The 1 RM of the stretched calf muscle significantly increased 29%, whereas the 1RM of the nonstretched calf muscle significantly increased 11%. In the control group, neither 1RM nor ROM changed for either leg. The results indicate that 10 weeks of stretching only the right calf will significantly increase the strength of both calves. Hence, chronic stretching can also induce a crosstraining effect for strength but not for the ROM. This study also validates earlier findings suggesting that stretching can elicit strength gains in untrained individuals.
... Zhou [362] suggested that EMS would lead to cross training e↵ects because there are a↵erences present. The authors were led to the hypothesis that long-term static stretching protocols could lead to cross training e↵ects as well as to increases in muscle strength [160,161,357]. To investigate the e↵ects, the authors performed a 10-week stretching training protocol for the plantar flexors for 4x30 sec for one leg. ...
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
... The timing of the stretching application to RT varied between the studies included herein. Stretch exercises were included before RT (8,19,35,48,50,79), in the inter-RT-set rest period (8,18,29,64,82,91), after RT (38,48,50,69), or on alternate days (40). The only study that compared distinct timings was that of Leite et al. (50), where authors examined stretching before or after RT sessions in comparison to an RT-only condition. ...
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.
... Regarding strength adaptations, previous literature on maximum strength performance with the addition of ISS is sparse. While adding static stretching to dynamic RT has shown to acutely decreases performance parameters, chronically it seems to provide similar or even greater strength adaptations [10,15,16]. Evangelista et al. 2019 were the only group to combine stretching in the inter-set rest period. ...
--[Correction: Table 2 updated to match text description of training program]--
The study examined the effects of adding a loaded stretch in the inter- set rest period (ISS) compared to traditional resistance training (TR) on muscular adaptations in resistance-trained males. Twenty-six subjects were randomly assigned into two groups (ISS: n=12; TR: n=14) and underwent an 8-week training regimen. Subjects in ISS underwent an additional loaded stretch for 30s at 15% of their working load from the prior set during the inter-set rest periods. Muscle thickness of the Pectoralis Major at the belly (BMT) and lateral (LMT) portions, 1RM and repetitions-to-failure (RTF) on the bench press exercise were measured at baseline and post 8-weeks of training. Additionally, volume load and perceptual parameters for exertion and recovery were measured. Both groups had similar total volume load and average perceptual parameters (p>0.05). There was a main time effect (p < 0.01) for all but one dependent variable indicating that both groups responded similarly across time [(∆BMT: ISS=2.7±1.7 mm; TR=3.0±2.2 mm), (∆LMT: ISS=3.2±1.6 mm; TR=2.8±1.7 mm, (∆1RM: ISS=6.6±3.8 kg; TR=7.5±5.7 kg;). Repetitions-to-failure did not change in either group (∆RTF: ISS=0.0±2.1 repetitions; TR=0.0±2.3 repetitions, p>0.05). Our results suggest that addition of a loaded ISS does not affect muscular adaptations either positively or negatively in resistance-trained males.
... Regarding strength adaptations, previous literature on maximum strength performance with the addition of ISS is sparse. While adding static stretching to dynamic RT has shown to acutely decreases performance parameters, chronically it seems to provide similar or even greater strength adaptations [10,15,16]. Evangelista et al. 2019 were the only group to combine stretching in the inter-set rest period. ...
The study examined the effects of adding a loaded stretch in the inter- set rest period (ISS) compared to traditional resistance training (TR) on muscular adaptations in resistance-trained males. Twenty-six subjects were randomly assigned into two groups (ISS: n=12; TR: n=14) and underwent an 8-week training regimen. Subjects in ISS underwent an additional loaded stretch for 30s at 15% of their working load from the prior set during the inter-set rest periods. Muscle thickness of the Pectoralis Major at the belly (BMT) and lateral (LMT) portions, 1RM and repetitions-to-failure (RTF) on the bench press exercise were measured at baseline and post 8-weeks of training. Additionally, volume load and perceptual parameters for exertion and recovery were measured. Both groups had similar total volume load and average perceptual parameters (p>0.05). There was a main time effect (p < 0.01) for all but one dependent variable indicating that both groups responded similarly across time [(∆BMT: ISS=2.7±1.7 mm; TR=3.0±2.2 mm), (∆LMT: ISS=3.2±1.6 mm; TR=2.8±1.7 mm, (∆1RM: ISS=6.6±3.8 kg; TR=7.5±5.7 kg;). Repetitions-to-failure did not change in either group (∆RTF: ISS=0.0±2.1 repetitions; TR=0.0±2.3 repetitions, p>0.05). Our results suggest that addition of a loaded ISS does not affect muscular adaptations either positively or negatively in resistance-trained males.
... Progression through a foam rolling program can help improve flexibility of the lower extremities and in turn facilitate further gains in strength. 65,66 The majority of athletes with focal chondral lesions have decreased lower extremity strength and more importantly a lack of single leg strength simply due to the fact of having progressive pain with strengthening exercises. The subsequent strength loss in these athletes can Osteochondral Allograft Transplantation in Professional Athletes: Rehabilitation and Return to Play lead to a "guarding" mechanism in the knee, which can be demonstrated by a flexed knee gait pattern, general lower extremity tightness, and increased tone around the knee joint and lower extremity. ...
For the treatment of large chondral and osteochondral defects of the knee, osteochondral allograft transplantation (OCA) is an effective solution with relatively high rates of return to sport. In professional athletes, rehabilitation following OCA is a critical component of the process of returning the athlete to full sports activity and requires a multidisciplinary team approach with frequent communication between the surgical and rehabilitation teams (physical therapists, athletic trainers, coaching staff). In this review, we describe our five-phase approach to progressive rehabilitation of the professional athlete after OCA, which takes into account the biological processes of healing and optimization of neuromuscular function required for the demands of elite-level sport. The principles of early range of motion, proper progression through the kinetic chain, avoidance of pain and effusion, optimization of movement, regimen individuation, and integration of sports-specific activities underlie proper recovery.
... Notwithstanding, these chronic effects of stretching on strength are derived from studies with questionable methodologic protocols, usually with a high risk of bias (Medeiros & Martini, 2018). Therefore, it might not be surprising that some studies report that chronic stretching is no better than a control group for improving strength (LaRoche, Lussier, & Roy, 2008), while others report that adding stretching to a resistance training protocol may enhance strength gains (Kakkonen, Nelson, Tarawhiti, Buckingham, & Winchester, 2010), and still, others describe how adding stretching to a resistance training protocol actually impaired strength gains (Bastos et al., 2013). ...
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.
... With regards to the effects of stretching on injury prevention; whilst there appear to be some indications that the risk of injury may be reduced under specific conditions (Woods et al., 2007), there is insufficient evidence to make strong recommendations to athletes (Thacker et al., 2004;Weldon and Hill, 2003). The impact of stretching on subsequent performance has been considered with some evidence of chronic performance enhancement (Kokkonen et al., 2007(Kokkonen et al., , 2010 and some of acute benefits following routines containing dynamic stretching (DS) (McMillian et al., 2006). However, there has also been a substantial amount of research highlighting acute decrements Email address: mark.glaister@stmarys.ac.uk (M. ...
Objective:
This study investigated the effect of brief static and dynamic stretching on spring-mass leg stiffness in a vertical bilateral hopping task.
Method:
38 men and 18 women were randomly assigned to either a natural (NAT; n = 27), or maximal (MAX; n = 29) hopping group. NAT bounced at their self-selected stiffness and MAX were instructed to bounce as stiffly as possible. Hopping was performed at 2.2 Hz on a force plate. After each of four treatment conditions (no stretch, 30 s stretch, multiple (4 × ) 30 s stretch, and dynamic stretch), subjects completed three × 30 s bouts (2 min rest periods) of hopping, in a counterbalanced crossover design. Stretches were performed on: gluteals, hamstrings, quadriceps and calves. Spring-mass leg stiffness was calculated as the ratio of peak vertical force to vertical displacement during ground contact.
Results:
The results revealed that men displayed greater leg stiffness than women (mean difference: 6.04 kN m-1; 95% likely range: 1.94-10.13 kN m-1), and that MAX produced higher stiffness values than NAT (mean difference: 10.93 kN m-1; 95% likely range: 6.84-15.03 kN m-1). Although there were no significant effects of treatment (p = 0.85) or time (p = 0.54) on leg stiffness, there was a significant treatment × time interaction (p = 0.015). Nevertheless, post hoc analyses were unable to identify where those differences were.
Conclusion:
Relative to controls, the results of this study showed that brief static stretching or non task-specific dynamic stretching does not affect spring-mass leg stiffness during vertical bilateral hopping.
... Although static stretching has demonstrated acute impairments in muscle strength, endurance, and power (24,29), some studies have shown that performing stretching exercise in a chronic fashion before strength training or on different days may optimize strength gains (15,16,18,28). Nevertheless, it is common for athletes and practitioners to implement stretching between sets when aiming to improve muscle recovery in sports or recreational exercises (10). ...
This study compared the effects of 8 weeks of traditional strength training (TST) and inter-set stretching (ISS) combined with TST on muscular adaptations. Twenty-nine sedentary, healthy adults were randomly assigned to either the TST (n=17; 28.0±6.4 years) or ISS (n=12; 26.8±6.1 years) group. Both groups performed six strength exercises encompassing the whole body (bench press, elbow extension, seated rows, biceps curl, knee extension and knee flexion) performing 4 sets of 8 to 12 repetitions maximum with 90-seconds rest between sets. However, the ISS group performed static passive stretching, at maximum amplitude, for 30 seconds between sets. Both groups performed training sessions twice a week on nonconsecutive days. Muscle strength (i.e. one repetition maximum or 1RM) and hypertrophy (i.e. muscle thickness [MT] via ultrasonography) were measured at pre-test and after 8-wks of training. Both groups increased 1RM bench-press (p≤0.0001): ISS (23.4%, CIdiff: 4.3kg to 11.1kg) and TST (22.2%, CIdiff: 5.2kg to 10.9kg) and 1RM knee extension (p≤0.0001): ISS (25.5%, CIdiff: 5.6kg to 15.0kg) and TST (20.6%, CIdiff: 4.4kg to 12.3kg). Both groups increased biceps brachii (BIMT), triceps brachii (TRMT) and rectus femoris (RFMT) Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation
... None of the subjects showed any evidence or complained of pain or muscle tenderness that is characteristic of the delayed onset muscle soreness associated with stretching active muscle. Possibly the best indicator of muscle damage is loss of force (Warren et al. 1999) and at 4 weeks there was no decrease in either isometric or concentric torque, although others have reported decreases (LaRoche et al. 2008;Kokkonen et al. 2010). It is possible that there may have been some loss of force in the time before the end of the study but we previously reported no significant force loss 24 h after a single training session. ...
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.
... Rozdílné závěry prezentují také studie zaměřené na dlouhodobý efekt, respektive na vliv statického strečinku ve vztahu k přírůstkům síly v čase. Kokkonen, Nelson, Tarawhiti, Buckingham a Winchester (2010) naměřili v testu svalového výkonu (1RM) po osmitýdenní intervenci u skupiny, která prováděla pravidelný statický strečink, nárůst síly u stehenních svalů a plantárních flexorů až o 31 % vyšší než u kontrolní skupiny bez strečinku. K obdobným závěrům v izometrickém testu síly plantárních flexorů dospěli i Ress, Murphy, Watsford, McLachlan a Coutts (2007) a zvýšení svalové síly přisuzují mechanickému stresu ve svalech a šlachách, který ovlivňuje strukturu kolagenu a proces syntézy proteinu, respektive proces hypertrofické adaptace. ...
... Exercise-induced muscle damage might also contribute to torque decline. However, there are a number of studies which have shown no significant deterioration of muscle strength after static stretching (LaRoche et al. 2008;Ryan et al. 2008;Kokkonen et al. 2010). Therefore, there is conflicting findings regarding static stretch induced deficits in performance and reason for this remains elusive, while may be explained partly by stretching duration, intensity, procedure, and subject population (Behm and Chaouachi 2011). ...
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.
... Median (IQD) CL (1) cises than are used in calisthenics may contribute to the higher gains in flexibility observed in the hatha yoga group. Long-term effects of flexibility training can be detected after 8-to-10 weeks and are closely related to the volume and intensity of stretching (Kokkonen, Nelson, Tarawhiti, Buckingham, & Winchester, 2010;Kokkonen, Nelson, Eldredgec, & Winchester, 2007). A number of underlying mechanisms have been proposed to explain these gains. ...
Flexibility training responses to distinct stretching techniques are not well defined, especially in the elderly. This study compared the flexibility of elderly individuals before and after having practiced hatha yoga and calisthenics for 1 year (52 weeks), at least 3 times/week. Sixty-six subjects (12 men) measured and assigned to 3 groups: control (n = 24, age = 67.7±6.9 years), hatha yoga (n = 22, age = 61.2±4.8 years), and calisthenics (n = 20, age = 69.0±5.8 years). The maximal range of passive motion of 13 movements in 7 joints was assessed by the Flexitest, comparing the range obtained with standard charts representing each arc of movement on a discontinuous and non-dimensional scale from 0 to 4. Results of individual movements were summed to define 4 indexes (ankle+knee, hip+trunk, wrist+elbow, and shoulder) and total flexibility (Flexindex). Results showed significant increases of total flexibility in the hatha yoga group (by 22.5 points) and the calisthenics group (by 5.8 points) (p < 0.01 for each) and a decrease in the control group (by 2.1 points) (p < 0.01) after one year of intervention. Between-group comparison showed that increases in the hatha yoga group were greater than in the calisthenics group for most flexibility indexes, particularly the overall flexibility (p <0.05). In conclusion, the practice of hatha yoga (i.e., slow/passive movements) was more effective in improving flexibility compared to calisthenics (i.e., fast/dynamic movements), but calisthenics was able to prevent flexibility losses observed in sedentary elderly subjects.
... 15 It was found in young adults that to maximize strength gains in the early phase of training, novice lifters should include static stretching exercises to their resistance training programs. 16 The effect of combination of resistance exercise and stretching on the fl exibility of older adults is not known. Thus, the objectives of the present study were to evaluate the effects of stretching and/or strength training, carried out twice a week, and to identify the effect of detraining on the fl exibility of the lower limbs in active elderly individuals. ...
Forty-five elderly persons (67 ± 2 years old) were divided into the following groups: control (CG), resistive exercise (REG), stretching (SG), and resistive exercise and stretching (RESG). All the groups participated in warm-up, but the REG and the RESG were followed by resistive exercise (65%, 70%, and 75% of a maximum of 10 repetitions); the SG participated in 60 seconds of stretching exercise; and RESG, participated in both. Range of motion was evaluated with a fleximeter. The SG increased hip flexion and maintained after detraining. The REG augmented dorsiflexion after 12 weeks. The RESG increased hip extension after 6 and 12 weeks and maintained after detraining. Resistive exercise and stretching, performed alone, were sufficient to increase range of motion. Stretching was determinant in an early gain and its maintenance.
... We and others have also shown that different versions of biomechanical strain can uniquely influence behavior of fibroblasts and their resulting secretions (7,36); therefore, strain may serve as a vehicle to direct fibroblast-mediated muscle repair. Supporting evidence shows that regimental stretching can reorganize fibroblast-rich connective tissue and induce muscle hypertrophy (14), which has lasting synergistic effects on strength gains and muscle activation (32). However, fibroblasts also synthesize fibrotic and inflammatory molecules, which are pathogenic to skeletal muscle (18,44), and repetitive tasks that result in excessive use of skeletal muscle and its surrounding muscle fascia can result in fibroblast-mediated inflammation, strain-induced injury, and dystonia (29). ...
Skeletal muscle functionality is governed by multiple stimuli including cytokines and biomechanical strain. Fibroblasts embedded within muscle connective tissue respond to biomechanical strain by secreting cytokines that induce myoblast differentiation and we hypothesize regulate myotube function. A coculture was established to allow crosstalk between fibroblasts in Bioflex wells, and myoblasts on non-deformable coverslips situated above Bioflex wells. Cyclic-short duration strain (CSDS) modeling repetitive stress/injury, acyclic long-duration strain (ALDS) modeling manipulative therapy, and combined strain paradigms (CSDS+ALDS) were applied to fibroblasts. Non-strained myoblasts in uniculture and coculture served as controls. After fibroblasts had induced myoblast differentiation, myotube contraction was assessed by perfusion of ACh[10(-11)-10(-3M)] and KCl[10(-2M)]. CSDS-fibroblasts increased myotube contractile sensitivity versus uniculture (P<0.05). As contraction is dependent upon ACh binding, expression and clustering of nicotinic receptors (nAChRs) were measured. CSDS-fibroblasts increased nAChR expression (P<0.05) which correlated with myotube contraction. ALDS-fibroblast did not significantly affect contraction nor nAChR expression. Agrin-treated myotubes were then used to design a computer algorithm to identify αBGT-stained nAChR clusters. ALDS-fibroblasts increased nAChR clustering (P<0.05); while CSDS-fibroblasts disrupted clusters from forming. CSDS-fibroblasts produced nAChRs preferentially located in non-clustered regions (P<0.05). Strain-activated fibroblasts mediate myotube differentiation with multiple functional phenotypes. Similar to muscle injury, CSDS-fibroblasts disrupted nAChR clusters and hypersensitized myotube contraction, while ALDS-fibroblasts aggregated nAChRs in large clusters which may have important clinical implications. Cellular strategies aimed at improving muscle functionality, such as through biomechanical strain vehicles that activate fibroblasts to stabilize neuromuscular junctions on nearby skeletal muscle may serve as novel targets in neuromuscular disorders.
Bu çalışmanın amacı, futbolcu çocuklarda farklı ısınma protokollerinin bazı performans değerleri üzerindeki etkilerinin incelenmesidir. Çalışmaya yaş ortalamaları 11,46±0,58 yıl, boy uzunluk ortalamaları 151,73±6,69 (cm) vücut ağırlık ortalamaları 41,47±6,83 kg. olan 23 futbolcu çocuk gönüllü olarak katılmıştır. Katılımcılara 48 saat arayla üç farklı ısınma protokolü uygulanmıştır. Bu ısınma protokolleri; 10 dakikalık ısınma koşusu (Metod A), dinamik+statik ısınma (Metod B), statik+dinamik ısınma (Metod C) olarak tasarlanmıştır. Her ısınma sonrası katılımcıların 30 m sürat, çeviklik, top sürme ve top sektirme performans değerleri ölçülmüştür. Veriler IBM SPSS 26 paket programı kullanılarak analiz edilmiştir. Gruplar arası karşılaştırmada tek yönlü varyans analizi (ANOVA), anlamlı olan ilişkilerin Post Hoc karşılaştırmalarında Tukey HSD testi kullanılmıştır. Anlamlılık düzeyi p<0,05 olarak kabul edilmiştir. Sonuç olarak, statik+dinamik ısınma protkolünün ısınma koşusu ve dinamik + statik ısınma protokollerine göre futbolcu çocukların top sürme ve top sektirme performanslarını pozitif yönde etkilediği tespit edilmiştir.
El objetivo de esta investigación fue determinar los resultados de la implementación de un programa para el desarrollo de la Flexibilidad en atletas de Boxeo y Muay Thai, sobre la ROM articulares y la producción de Velocidad de los golpes rectos de puño. Se utilizó una metodología cuantitativa con un diseño de investigación preexperimental de corte longitudinal. A partir de la evaluación de la Flexibilidad en 10 atletas de Boxeo y Muay Thai utilizando el método Flexitest, y tras evidenciar los niveles más bajos de esta capacidad en las zonas de tobillo, hombro y muñeca, se desarrolló un programa de entrenamiento de 6 semanas de duración utilizando los métodos dinámico, estático y FNP para el entrenamiento de estas zonas. También se evaluaron las Velocidades pico alcanzadas por los participantes en golpes de puño rectos lanzados al aire. Se observaron diferencias estadísticamente significativas al comparar los rangos articulares pre y post programa de entrenamiento de la Flexibilidad en las articulaciones de tobillo y hombro (p=0.006 y p=0.005, respectivamente). Con respecto a la Velocidad no se observaron diferencias estadísticamente significativas en ninguno de los gestos evaluados. La fuerza de asociación resultó de baja a nula al correlacionar la Flexibilidad y producción de Velocidad de los gestos. Si bien se mejoró la Flexibilidad de hombros y tobillos, la Velocidad de los gestos de golpeo no se vio modificada y no se pudo considerar una asociación entre ambas variables.
RESUMO A investigação das possíveis influências entre o treinamento de flexibilidade e o desempenho de força muscular pode contribuir para a compreensão do treinamento. O objetivo do presente estudo foi verificar o efeito de três semanas de treinamento de flexibilidade no torque e potência muscular. Dez adultos, divididos em Grupo Alongamento (GA, N=5) e Controle (GC, N=5) foram avaliados antes e após a intervenção. A intervenção foi realizada pelo GA e consistiu em um protocolo de alongamento estático passivo para os músculos posteriores da coxa, realizados em três por semana e durante três semanas. O torque e potência da extensão e flexão dos joelhos foram avaliados utilizando dinamômetro isocinético em três velocidades (60, 180 e 360º/s). A amplitude de movimento (ADM) foi avaliada pelo teste de sentar e alcançar. Houve incremento de ADM (pré: 23,0±5,6cm; pós: 30,1±6,58cm; p=0,033) do GA, mas não foram observadas diferenças entre e intra-grupos para as demais variáveis (p>0,05). Houveram correlações da ADM apenas para o torque da flexão (r=0,664; p=0,036) e potência da extensão (r=0,638; p=0,047) do joelho esquerdo a 60º/s. Conclui-se que três semanas de treinamento de flexibilidade com método estático passivo promoveu ganhos significativos de ADM, mas não possibilitou incrementos de torque e potência. Palavras-chave: Amplitude de movimento articular. Força Muscular. Dinamômetro de força muscular. Desempenho. ABSTRACT Investigation about influences between stretching training and muscle strength performance can contribute to the understanding of training. The aim of the present study was to verify the effect of three weeks of stretching training on muscle torque and power. Ten adults, divided into Stretching Group (GA, N = 5) and Control Group (CG, N = 5) were evaluated pre and post intervention. The intervention was performed by GA and consisted of a passive static stretching protocol for the posterior thigh muscles, performed three times a week and during three weeks. The torque and power of the knee extension and flexion were evaluated using an isokinetic dynamometer at three speeds (60, 180 and 360º/s). Range of motion (ROM) was assessed using the sit and reach test. There was an increase in ROM (pre: 23.0 ± 5.6 cm; post: 30.1 ± 6.58 cm; p = 0.033) of GA, but there were no differences between and within groups for the other variables (p> 0.05). There were correlations of the ROM only for the flexion torque (r = 0.664; p = 0.036) and power of the extension (r = 0.638; p = 0.047) of the left knee at 60º/s. It was concluded that three weeks of static stretching training promoted significant gains in ROM, but did not allow increases in torque and power. Introdução Força e flexibilidade são capacidades físicas importantes à realização das atividades de vida diárias e gestos motores 1. Estudos investigaram as possíveis inter-relações entre as manifestações de flexibilidade e força 2-4 , reportando contribuições para incrementos de amplitudes de movimento (ADM) 3,5. Não obstante, em relação à influência do treinamento de flexibilidade (TF) no desempenho de força, observam-se efeitos agudos ou crônicos 5,6. O efeito agudo está relacionado a prejuízos na manifestação de força muscular na ordem de 4,5-28% para contrações isotônicas e isométricas e de 3,2-7,3% para o desempenho de saltos quando precedidos por alongamentos 7,8. Por sua vez, o efeito crônico tem sido observado em investigações que conduziram TF regulares (2-3 vezes por semana) 6 em amostra de indivíduos
RESUMO A investigação das possíveis influências entre o treinamento de flexibilidade e o desempenho de força muscular pode contribuir para a compreensão do treinamento. O objetivo do presente estudo foi verificar o efeito de três semanas de treinamento de flexibilidade no torque e potência muscular. Dez adultos, divididos em Grupo Alongamento (GA, N=5) e Controle (GC, N=5) foram avaliados antes e após a intervenção. A intervenção foi realizada pelo GA e consistiu em um protocolo de alongamento estático passivo para os músculos posteriores da coxa, realizados em três por semana e durante três semanas. O torque e potência da extensão e flexão dos joelhos foram avaliados utilizando dinamômetro isocinético em três velocidades (60, 180 e 360º/s). A amplitude de movimento (ADM) foi avaliada pelo teste de sentar e alcançar. Houve incremento de ADM (pré: 23,0±5,6cm; pós: 30,1±6,58cm; p=0,033) do GA, mas não foram observadas diferenças entre e intra-grupos para as demais variáveis (p>0,05). Houveram correlações da ADM apenas para o torque da flexão (r=0,664; p=0,036) e potência da extensão (r=0,638; p=0,047) do joelho esquerdo a 60º/s. Conclui-se que três semanas de treinamento de flexibilidade com método estático passivo promoveu ganhos significativos de ADM, mas não possibilitou incrementos de torque e potência. Palavras-chave: Amplitude de movimento articular. Força Muscular. Dinamômetro de força muscular. Desempenho. ABSTRACT Investigation about influences between stretching training and muscle strength performance can contribute to the understanding of training. The aim of the present study was to verify the effect of three weeks of stretching training on muscle torque and power. Ten adults, divided into Stretching Group (GA, N = 5) and Control Group (CG, N = 5) were evaluated pre and post intervention. The intervention was performed by GA and consisted of a passive static stretching protocol for the posterior thigh muscles, performed three times a week and during three weeks. The torque and power of the knee extension and flexion were evaluated using an isokinetic dynamometer at three speeds (60, 180 and 360º/s). Range of motion (ROM) was assessed using the sit and reach test. There was an increase in ROM (pre: 23.0 ± 5.6 cm; post: 30.1 ± 6.58 cm; p = 0.033) of GA, but there were no differences between and within groups for the other variables (p> 0.05). There were correlations of the ROM only for the flexion torque (r = 0.664; p = 0.036) and power of the extension (r = 0.638; p = 0.047) of the left knee at 60º/s. It was concluded that three weeks of static stretching training promoted significant gains in ROM, but did not allow increases in torque and power. Introdução Força e flexibilidade são capacidades físicas importantes à realização das atividades de vida diárias e gestos motores 1. Estudos investigaram as possíveis inter-relações entre as manifestações de flexibilidade e força 2-4 , reportando contribuições para incrementos de amplitudes de movimento (ADM) 3,5. Não obstante, em relação à influência do treinamento de flexibilidade (TF) no desempenho de força, observam-se efeitos agudos ou crônicos 5,6. O efeito agudo está relacionado a prejuízos na manifestação de força muscular na ordem de 4,5-28% para contrações isotônicas e isométricas e de 3,2-7,3% para o desempenho de saltos quando precedidos por alongamentos 7,8. Por sua vez, o efeito crônico tem sido observado em investigações que conduziram TF regulares (2-3 vezes por semana) 6 em amostra de indivíduos
Background:
Many resistance studies state that they used the traditional method of resistance training in the intervention. However, there is a wide difference on the characteristics of the training protocols used even though they are labeled as "the traditional method". There is no clear definition and characteristics for the traditional method of resistance training.
Objective:
To describe the most common definitions and references, and also the main characteristics of the training variables of the studies using the traditional training method for strengthening.
Database:
Searches were carried out in Pubmed, Embase, SPORTDiscus and Web of Science.
Study selection:
We included randomized controlled trials that included a strengthening program using the "traditional method" and that evaluated hypertrophy and/or maximum strength in healthy individuals.
Result:
The initial search resulted in 26,057 studies, but only 39 studies were eligible and included in this review. The common characteristics of the traditional training protocol were frequency of 3 sessions/week, 3 sets of 9 repetitions, with weight = 75% 1RM. The movement time was 2±1 seconds for the concentric and for the eccentric phases. Resting time between sets was 2±1 minutes. The concepts used to define the method as traditional and the characteristics of the intervention protocols were different. The American College of Sports Medicine (ACSM) was the most cited reference.
Conclusions:
The "traditional method of resistance training" can be defined as: "Three (±1) sets of 9±6 repetitions of concentric and eccentric exercises using an external load of 75±20% of one maximum repetition, completed 3±1 times/week.
The purpose of this study was to examine the effects of the combination of static stretching (SS) and electrical stimulation (ES) for 8 weeks on joint range of motion (ROM), muscle strength, and muscle architecture. Thirty-one subjects were divided into three groups: the SS combined with ES (SS+ES) group, SS group, or control group. The SS+ES group performed calf stretching simultaneously with ES to the gastrocnemius medialis, while the SS group performed calf stretching only. The training regimen consisted of four 30 sec sets of stretching, with 30 sec rest intervals, 3 days per week for 8 weeks. The control group did not perform any intervention exercise. Before and after training, measurements were taken to determine the ankle ROM, plantar flexion one repetition maximum strength, muscle thickness, pennation angle, and circumference of the lower leg. The results showed that 8 weeks of training led to significant improvements in the ankle ROM and muscle thickness in both the SS+ES and SS groups. There were significant increases in plantar flexion one repetition maximum strength and pennation angle in all three groups. For all parameters, there was no difference between the SS+ES and SS groups. These results clarify that 8 weeks of SS improves joint ROM and muscle thickness, and show that there is no additional benefit gained by combining ES with SS in this particular training regime.
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.
O objetivo do presente estudo foi verificar o efeito agudo do alongamento estático e facilitação neuromuscular propriocetiva (FNP) no desempenho do número de repetições máximas (RM) numa sessão de treino de força (STF). Seis visitas foram realizadas. Nas três primeiras adotou-se uma familiarização com os protocolos de alongamento e teste e reteste de 12RM. Os voluntários foram divididos aleatoriamente nas seguintes condições experimentais: a) protocolo de alongamento estático + STF; b) protocolo de alongamento FNP + STF; c) protocolo de aquecimento específico com 20 repetições a 30% da carga de 12RM + STF. Realizaram-se 3 séries de 12RM para cada exercício: leg press (LP), cadeira extensora (CE), mesa flexora (MF) e panturrilha (PT). Para o somatório do número de RM das 3 séries de cada exercício, diferenças significativas (p < .05) foram encontradas entre os métodos nos exercícios LP, CE e MF. Para o somatório do número de RM das três séries dos quatro exercícios encontraram-se diferenças significativas (p < .05) para EP vs. AE e FNP vs. AE. Ambos os métodos de alongamento diminuíram o desempenho, reduzindo os níveis de força. Desta forma, os alongamentos FNP e estático não devem ser recomendados antes de uma sessão de treino de força.
Although there is considerable research on concurrent training, none has integrated flexible nonlinear periodization and maximal effort cycling in the same design. The purpose of this investigation was to test outcome measures of strength and power using a pretest-posttest randomized-groups design. A strength and endurance group (SE) was compared to a strength, endurance, and maximal effort cycling group (SEC). Both groups used a flexible nonlinear periodization design. Thirteen male and seven female students (mean± SD: age, 22.5± 4.1 years; height, 173.5 ± 12.4cm; weight, 79.4 ± 20.2kg; weightlifting experience, 2.4 ± 2.2 years) participated in this study. Groups were not matched for age, height, weight, weightlifting experience, or sex, but were randomly assigned to a SE (n=10) or SEC (n=10) group. All training was completed within 45 minutes, twice per week (Monday and Wednesday), over 12 consecutive weeks. Both groups were assigned 6.75 total hours of aerobic conditioning, and 13.5 hours of free weight and machine exercises totaling 3,188 repetitions ranging from 5-20 Repetition Maximums (RMs). The SEC group performed 2 cycling intervals per workout ranging from 10-45s. Pre-and posttest measures included chest press and standing broad jump. Analysis of variance showed that there were no significant differences between (SE) and (SEC) on measures of chest press or standing broad jump performance (p=n.s.). Paired sample t-tests (p=.05), showed significant improvement in strength and power in all groups (pretest to posttest), except SE jump performance (p=n.s.). The conclusion from this study is that adding maximal effort cycling does not provide additional strength or power benefits to a concurrent flexible nonlinear training program. However, an exercise professional can take confidence that a concurrent, flexible nonlinear training program can increase strength and power in healthy individuals.
Previous research has shown that passive muscle stretching can diminish the peak force output of subsequent maximal isometric and concentric contractions. The purpose of the present study was twofold: 1. to establish if the deleterious effect of stretching on performance also exists for a skill that relies on the rate of force production for success rather than peak force generation and 2. to determine if a similar effect exists for a movement that employs a stretch-shortening action. Ten participants performed two types of maximal vertical jump with and without prior stretching of the hip and knee extensors. Both static jumps (SJ) and countermovement jumps (CMJ) were executed from a force platform. Jump height was calculated from the velocity at takeoff determined from the force/time data. Stretching induced a significant (p<0.05) decrease in jump height for both the SJ (4.4 ± 1.3%) and CMJ (4.3 ± 1.3%). Thus, it appears that pre-performance stretching exercises might negatively impact skills that demand a high power output in addition to those that rely simply on maximizing peak force. Furthermore, it is possible that this detrimental effect is comparable for skills that take advantage of the stretch-shortening phenomenon and those that do not.
Background
The beneficial effects of cardiorespiratory fitness on mortality are well known; however, the relation of muscular fitness, specifically muscular strength and endurance, to mortality risk has not been thoroughly examined. The purpose of the current study is to determine if a dose-response relation exists between muscular fitness and mortality after controlling for factors such as age and cardiorespiratory fitness.
Methods
The study included 9105 men and women, 20–82 years of age, in the Aerobics Center Longitudinal Study who have completed at least one medical examination at the Cooper Clinic in Dallas, TX between 1981 and 1989. The exam included a muscular fitness assessment, based on 1-min sit-up and 1-repetition maximal leg and bench press scores, and a maximal treadmill test. We conducted mortality follow-up through 1996 primarily using the National Death Index, with a total follow-up of 106,046 person-years. All-cause mortality rates were examined across low, moderate, and high muscular fitness strata.
Results
Mortality was confirmed in 194 of 9105 participants (2.1%). The age- and sex-adjusted mortality rate of those in the lowest muscular fitness category was higher than that of those in the moderate fitness category (26.8 vs. 15.3 per 10,000 person-years, respectively). Those in the high fitness category had a mortality rate of 20.6 per 10,000 person-years. The moderate and high muscular fitness groups had relative risks of 0.64 (95%CI = 0.44–0.93) and 0.80 (95%CI = 0.49–1.31), adjusting for age, health status, body mass index, cigarette smoking, and cardio-respiratory fitness when compared with the low muscular fitness group.
Conclusions
Mortality rates were lower for individuals with moderate/high muscular fitness compared to individuals with low muscular fitness. These findings warrant further research to confirm the apparent threshold effect between low and moderate/high muscular fitness and all-cause mortality.
The purpose of this study was to 1) compare two commonly practiced stretching techniques to determine which is most effective for improving hip range of motion, and 2) evaluate the effect of these techniques on gait economy. Seven asymptomatic males, 18-22 years of age, served as subjects. Goniometric measurements of hip range of motion (ROM) and gait economy, as measured by submaximal oxygen consumption of walking and running on a treadmill, were taken before and after each of the two stretching procedures, (a) static stretching, and (b) soft tissue mobilization with proprioceptive neuromuscular facilitation (STM/PNF). Static stretching procedures resulted in significant improvements in ROM for hip extension (p < 0.01) and hip flexion (p < 0.01). The STM/PNF also resulted in significant improvements in hip extension ROM (p < 0.01) and hip flexion ROM (p < 0.05). There was a significant improvement in gait economy at 40% VO2max (p < 0.05), at 60% VO2max (p < 0.05), and at 80% VO2max (p < 0.01) following the static stretching procedure. The STM/PNF procedure improved gait economy only at one workload, 60% of VO2max (p < 0.05). These results suggest that a single bout of static stretching or STM/PNF was effective for improving hip ROM but static stretching was more effective for improving gait economy in young, asymptomatic males. J Orthop Sports Phys Ther 1989;10(9):350-357.
Sixteen experienced male powerlifters served as subjects in a training study designed to examine the effect of flexibility training on: (i) the stiffness of the series elastic components (SEC) of the upper body musculature and (ii) rebound and purely concentric bench press performance. Nine of the subjects participated in two sessions of flexibility training twice per week for 8 wk. Prior to and after the training period the subjects' static flexibility, SEC stiffness, rebound bench press (RBP), and purely concentric bench press (PCBP) performance were recorded. The flexibility training induced a significant reduction in the maximal stiffness of the SEC. Furthermore, the experimental subjects produced significantly more work during the initial concentric portion of the RBP lift, enabling a significantly greater load to be lifted in the post-training testing occasion. The benefits to performance achieved by the experimental group consequent to flexibility training were greater during the RBP lift as compared with the PCBP lift. The control subjects exhibited no change in any variable over the training period. These results implied that the RBP performance enhancement observed consequent to flexibility training was directly caused by a reduction in SEC stiffness, increasing the utilization of elastic strain energy during the RBP lift.
The effect of repeated strains on rat soleus muscles was investigated by stretching active muscles 3 times/wk for 4 wk with two different methods of stretching. The adaptation of myofibers and noncontractile tissue was followed by histochemical techniques and computer-assisted image analysis. Muscle hypertrophy was seen in the slow-stretched muscles, which increased in mass by 13% and increased in myofiber cross-sectional area by 30%. In the fast-stretched muscle, mass increased by 10% but myofiber cross-sectional area actually decreased. This decrease in mean fiber area was the result of a population of very small fibers (population A) that coexisted with slightly smaller normal-sized fibers (population B). Fibers in population A did not have the distribution expected from atrophy compared with atrophic fibers from unloaded muscles; they were much smaller. In addition, there was a 44% increase in noncontractile tissue in the fast-stretched muscles. Thus, soleus muscles subjected to repeated strains respond differently to slow and fast stretching. Slow stretching results in typical muscle hypertrophy, whereas fast stretching produces somewhat larger muscles but with a mixture of small and normal-sized myofibers accompanied by a marked proliferation of noncontractile tissue.
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 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.
The purpose of this study was to investigate the factors underlying the force loss occurring after prolonged, static, passive stretching. Subjects were tested before and 5-10 min following 20 min of static, passive stretching of the quadriceps (N=12) or a similar period of no stretch (control, N=6). Measurements included isometric maximal voluntary contraction (MVC) force, surface integrated electromyographic (iEMG) activity of the quadriceps and hamstrings, evoked contractile properties (twitch and tetanic force), and quadriceps inactivation as measured by the interpolated twitch technique (ITT). Following stretching, there was a significant 12% decrement in MVC with no significant changes in the control group. Muscle inactivation as measured by the ITT and iEMG increased by 2.8% and 20.2%, respectively. While twitch forces significantly decreased 11.7%, there was no change in tetanic force post-stretch. Although possible increases in muscle compliance affected twitch force, a lack of tetanic force change would suggest that post-stretch force decrements are more affected by muscle inactivation than changes in muscle elasticity.
Low muscle strength is associated with mortality, presumably as a result of low muscle mass (sarcopenia) and physical inactivity. Grip strength was longitudinally collected in 1071 men over a 25-year period. Muscle mass was estimated by using 24-hour creatinine excretion and physical activity values, obtained by questionnaire. Survival analysis examined the impact of grip strength and rate of change in strength on all-cause mortality over 40 years. Lower and declining strength are associated with increased mortality, independent of physical activity and muscle mass. In men <60 years, rate of loss of strength was more important than the actual levels. In men >/=60 years, strength was more protective than the rate of loss, which persisted when muscle mass was considered. Strength and rate of change in strength contribute to the impact of sarcopenia on mortality. Although muscle mass and physical activity are important, they do not completely account for the impact of strength and changes in strength.
The editorial policies of several prominent educational and psychological journals require that researchers report some measure of effect size along with tests for statistical significance. In analysis of variance contexts, this requirement might be met by using eta squared or omega squared statistics. Current procedures for computing these measures of effect often do not consider the effect that design features of the study have on the size of these statistics. Because research-design features can have a large effect on the estimated proportion of explained variance, the use of partial eta or omega squared can be misleading. The present article provides formulas for computing generalized eta and omega squared statistics, which provide estimates of effect size that are comparable across a variety of research designs.
The aim of the present study was to determine the effect of stretching applied every 3 days to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Eighteen 16-week-old Wistar rats were used and divided into three groups of 6 animals each: a) the left soleus muscle was immobilized in the shortened position for 3 weeks; b) during immobilization, the soleus was stretched for 40 min every 3 days; c) the non-immobilized soleus was only stretched. Left and right soleus muscles were examined. One portion of the soleus was frozen for histology and muscle fiber area evaluation, while the other portion was used to identify the number and length of serial sarcomeres. Immobilized muscles (group A) showed a significant decrease in weight (44 +/- 6%), length (19 +/- 7%), serial sarcomere number (23 +/- 15%), and fiber area (37 +/- 31%) compared to the contralateral muscles (P < 0.05, paired Student t-test). The immobilized and stretched soleus (group B) showed a similar reduction but milder muscle fiber atrophy compared to the only immobilized group (22 +/- 40 vs 37 +/- 31%, respectively; P < 0.001, ANOVA test). Muscles submitted only to stretching (group C) significantly increased the length (5 +/- 2%), serial sarcomere number (4 +/- 4%), and fiber area (16 +/- 44%) compared to the contralateral muscles (P < 0.05, paired Student t-test). In conclusion, stretching applied every 3 days to immobilized muscles did not prevent the muscle shortening, but reduced muscle atrophy. Stretching sessions induced hypertrophic effects in the control muscles. These results support the use of muscle stretching in sports and rehabilitation.
Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the "strength-endurance continuum". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, prolonged contractions, with significant increases after training in aerobic power and time to exhaustion. Thus, low and intermediate RM training appears to induce similar muscular adaptations, at least after short-term training in previously untrained subjects. Overall, however, these data demonstrate that both physical performance and the associated physiological adaptations are linked to the intensity and number of repetitions performed, and thus lend support to the "strength-endurance continuum".
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.
High-resistance strength training (HRST) is one of the most widely practiced forms of physical activity, which is used to enhance athletic performance, augment musculo-skeletal health and alter body aesthetics. Chronic exposure to this type of activity produces marked increases in muscular strength, which are attributed to a range of neurological and morphological adaptations. This review assesses the evidence for these adaptations, their interplay and contribution to enhanced strength and the methodologies employed. The primary morphological adaptations involve an increase in the cross-sectional area of the whole muscle and individual muscle fibres, which is due to an increase in myofibrillar size and number. Satellite cells are activated in the very early stages of training; their proliferation and later fusion with existing fibres appears to be intimately involved in the hypertrophy response. Other possible morphological adaptations include hyperplasia, changes in fibre type, muscle architecture, myofilament density and the structure of connective tissue and tendons. Indirect evidence for neurological adaptations, which encompasses learning and coordination, comes from the specificity of the training adaptation, transfer of unilateral training to the contralateral limb and imagined contractions. The apparent rise in whole-muscle specific tension has been primarily used as evidence for neurological adaptations; however, morphological factors (e.g. preferential hypertrophy of type 2 fibres, increased angle of fibre pennation, increase in radiological density) are also likely to contribute to this phenomenon. Changes in inter-muscular coordination appear critical. Adaptations in agonist muscle activation, as assessed by electromyography, tetanic stimulation and the twitch interpolation technique, suggest small, but significant increases. Enhanced firing frequency and spinal reflexes most likely explain this improvement, although there is contrary evidence suggesting no change in cortical or corticospinal excitability. The gains in strength with HRST are undoubtedly due to a wide combination of neurological and morphological factors. Whilst the neurological factors may make their greatest contribution during the early stages of a training programme, hypertrophic processes also commence at the onset of training.
Previous research has shown that static stretching (SS) can diminish the peak force output of stretch-shortening cycle actions while performing a dynamic warm-up (DW) protocol has been shown to enhance performance in similar activities. The purpose of this study was to establish whether the deleterious effects of SS would wash out the performance enhancements obtained from the DW. Eleven males and 11 females, who were athletes of a NCAA Division I track team, performed a DW followed with either a SS or rest (NS) condition. After warm-up was completed, three 40 m sprints were performed to investigate the effects of the SS condition on sprint performance when preceded by DW. Time(s) were obtained from timing gates placed at 0, 20, and 40 m respectively. Testing was conducted over 2 days with a 1 week washout period. Testing order was balanced to eliminate possible order effect. Time for the NS versus the SS group was significantly faster for the second 20 m with a time of 2.41 versus 2.38 seconds (P < or = .05), and for the entire 40 m with a time of 5.6 +/- 0.4 versus 5.7 +/- 0.4 seconds (P < or = .05). The results of this study suggest that performing a SS protocol following a DW will inhibit sprint performance in collegiate athletes.
We finally solved our copyright problems to make this book available in a eVersion that you can download! This is the same as the 3rd edition in print but the copyright reverted to me and I have posted it on the Shirley Ryan AbilityLab to download for a nominal $20 (US Dollars) that goes to the AbilityLab. Enjoy!
https://www.sralab.org/academy/bookstore/skeletal-muscle-structure-function-and-plasticity
A study was conducted on the effects of continual heavy, resistive exercise on the range of movement in certain selected joints of young male adults. An experimental group (n = 13) trained with weights for approximately six months during which time a control group (n = 13) participated in general physical education activities. Weight training did not have an appreciable effect upon range of joint movement throughout the body. A significant decrease did take place in the ability of the experimental group to move the extended arms, from a position at the side of the body, backward in the anteroposterior plane.
High-resistance strength training (HRST) is one of the most widely practiced forms of physical activity, which is used to enhance athletic performance, augment musculo-skeletal health and alter body aesthetics. Chronic exposure to this type of activity produces marked increases in muscular strength, which are attributed to a range of neurological and morphological adaptations. This review assesses the evidence for these adaptations, their interplay and contribution to enhanced strength and the methodologies employed.
The primary morphological adaptations involve an increase in the cross-sectional area of the whole muscle and individual muscle fibres, which is due to an increase in myofibrillar size and number. Satellite cells are activated in the very early stages of training; their proliferation and later fusion with existing fibres appears to be intimately involved in the hypertrophy response. Other possible morphological adaptations include hyperplasia, changes in fibre type, muscle architecture, myofilament density and the structure of connective tissue and tendons.
Indirect evidence for neurological adaptations, which encompasses learning and coordination, comes from the specificity of the training adaptation, transfer of unilateral training to the contralateral limb and imagined contractions. The apparent rise in whole-muscle specific tension has been primarily used as evidence for neurological adaptations; however, morphological factors (e.g. preferential hypertrophy of type 2 fibres, increased angle of fibre pennation, increase in radiological density) are also likely to contribute to this phenomenon. Changes in inter-muscular coordination appear critical. Adaptations in agonist muscle activation, as assessed by electromyography, tetanic stimulation and the twitch interpolation technique, suggest small, but significant increases. Enhanced firing frequency and spinal reflexes most likely explain this improvement, although there is contrary evidence suggesting no change in cortical or corticospinal excitability.
The gains in strength with HRST are undoubtedly due to a wide combination of neurological and morphological factors. Whilst the neurological factors may make their greatest contribution during the early stages of a training programme, hypertrophic processes also commence at the onset of training.
Background: The beneficial effects of cardiorespiratory fitness on mortality are well known; however, the relation of muscular fitness, specifically muscular strength and endurance, to mortality risk has not been thoroughly examined. The purpose of the current study is to determine if a dose-response relation exists between muscular fitness and mortality after controlling for factors such as age and cardiorespiratory fitness. Methods: The study included 9105 men and women, 20–82 years of age, in the Aerobics Center Longitudinal Study who have completed at least one medical examination at the Cooper Clinic in Dallas, TX between 1981 and 1989. The exam included a muscular fitness assessment, based on 1-min sit-up and 1-repetition maximal leg and bench press scores, and a maximal treadmill test. We conducted mortality follow-up through 1996 primarily using the National Death Index, with a total follow-up of 106,046 person-years. All-cause mortality rates were examined across low, moderate, and high muscular fitness strata. Results: Mortality was confirmed in 194 of 9105 participants (2.1%). The age-and sex-adjusted mortality rate of those in the lowest muscular fitness category was higher than that of those in the moderate fitness category (26.8 vs. 15.3 per 10,000 person-years, respectively). Those in the high fitness category had a mortality rate of 20.6 per 10,000 person-years. The moderate and high muscular fitness groups had relative risks of 0.64 (95%CI = 0.44–0.93) and 0.80 (95%CI = 0.49–1.31), adjusting for age, health status, body mass index, cigarette smoking, and cardio-respiratory fitness when compared with the low muscular fitness group. Conclusions: Mortality rates were lower for individuals with moderate/high muscular fitness compared to individuals with low muscular fitness. These findings warrant further research to confirm the apparent threshold effect between low and moderate/high muscular fitness and all-cause mortality.
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After immobilisation of muscle in a shortened position there is a reduction of muscle fibre length due to a loss of serial sarcomeres. Experiments have been carried out to determine whether short, daily periods of stretch prevent sarcomere loss and the resultant loss of range of joint motion. It was found that periods of stretch as short as 1/2 h daily were sufficient not only to prevent loss of sarcomeres but actually to cause an increase in the number of sarcomeres in series. Range of joint motion was normal. Such short periods of stretch were also found to prevent much of the muscle atrophy normally associated with immobilisation in the shortened position.
The relationship between hamstring flexibility and hamstring muscle performance has not been reported. The purposes of this study were 1) to determine the most effective stretching method for increasing hamstring flexibility and 2) to determine the effects of increasing hamstring flexibility on isokinetic peak torque. Nineteen subjects participated in this study. A two-way analysis of variance was used to compare two stretching techniques: proprioceptive neuromuscular facilitation stretch and static stretch. A one-way repeated measures analysis of variance was used to compare hamstring isokinetic values pre- and poststretching. No significant increase occurred (p < .05) in hamstring flexibility even though increases occurred with each technique: static stretch (+21.3%) and proprioceptive neuromuscular facilitation (+25.7%). Significant increases occurred in peak torque eccentrically at 60 degrees/sec (p < .05, +8.5%) and 120 degrees/sec (p < .05, +13.5%) and concentrically at 120 degrees/sec (p < .05, +11.2%). No significant increase occurred at 60 degrees/sec (p > .05, +2.5%). We concluded that increasing hamstring flexibility was an effective method for increasing hamstring muscle performance at selective isokinetic conditions. Further study is needed to determine if increasing hamstring flexibility will increase performance in closed kinetic chain activities.
Studies of limb lengthening have demonstrated successful bone formation in the distraction gap. Failure of the muscle units to lengthen leads to many complications that significantly limit the success of this approach; it is, therefore, of paramount importance to characterize the behavior of the muscle during limb lengthening. In this study, tibiae of adult rabbits were lengthened for 10 days at a rate of 1 mm/day. The proliferative ability of the lengthened muscle was characterized using bromodeoxyuridine, a thymidine analogue that is incorporated during cell division, and desmin, a muscle-specific marker. We observed a large number of proliferating cells, specifically in the lengthened muscle, that were co-localized with many desmin-positive cells. The presence of bromodeoxyuridine nuclei inside desmin-positive muscle fibers suggests that limb lengthening promotes muscle growth by triggering myoblast proliferation and fusion into the lengthened muscle. Our findings are consistent with those of other studies in the reviewed literature that also suggest that limb lengthening promotes muscle growth.
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.
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.
The purpose of this study was to assess the effects of power and flexibility training on countermovement and drop jump techniques.
All jumps were executed with the goal of attaining maximum height and no restrictions were placed on the magnitude of countermovement or ground contact time. Subjects underwent initial testing followed by random allocation to one of four groups: power training to increase vertical jump height (P), stretching to increase flexibility (S), a combination of power and stretch training (PS), and a control group (C). Training lasted for 10 wk, followed by retesting. Jump height was calculated in addition to the following technique variables: eccentric lower-limb stiffness produced during the countermovement phase, magnitude of countermovement, and in the case of the drop jumps, ground contact time.
Groups PS, P, and S all increased countermovement jump (CMJ) height, but only groups PS and P increased drop jump height (DJ30, DJ60, and DJ90 for drop jumps performed from 30-, 60-, and 90-cm drop heights). The technique changes associated with power training were increases in magnitude of countermovement (CMJ, DJ30, DJ60, and DJ90) and increases in ground contact time (DJ30 and DJ60). In addition, the eccentric lower-limb stiffness produced during the countermovement phase of the jumps increased for CMJ and decreased for DJ30, DJ60, and DJ90. Stretching appeared to have no significant effect on CMJ or drop jump technique.
The results of this study show that when the training goal is maximum jump height alone, it is likely that drop jump technique will change in the direction of a lower eccentric leg stiffness, greater depth of countermovement, and a longer ground contact time, whereas for a countermovement jump eccentric leg stiffness and the depth of countermovement will both increase. It is proposed that these technique changes are a result of attempting to optimize a complex combination of factors involved in jumping (e.g., utilization of elastic energy, Golgi tendon organ inhibition, and contractile component contribution).
The purpose of this study was to determine whether a flexibility training program, a weight training program, and the combination of both would affect running speed when used as supplementary training programs to the conventional method of training sprinters. One hundred and forty-five subjects, randomly assigned to one of five training groups, were tested for flexibility, leg strength, and running speed before and after an 8-week training period. Results showed that both weight training and flexibility training, as supplements to sprint training, increased running speed significantly more than an unsupplemented sprint training program.
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.
Since strength and muscular strength endurance are linked, it is possible that the inhibitory influence that prior stretching has on strength can also extend to the reduction of muscle strength endurance. To date, however, studies measuring muscle strength endurance poststretching have been criticized because of problems with their reliability. The purpose of this study was twofold: both the muscle strength endurance performance after acute static stretching exercises and the repeatability of those differences were measured. Two separate experiments were conducted. In experiment 1, the knee-flexion muscle strength endurance exercise was measured by exercise performed at 60 and 40% of body weight following either a no-stretching or stretching regimen. In experiment 2, using a test-retest protocol, a knee-flexion muscle strength endurance exercise was performed at 50% body weight on 4 different days, with 2 tests following a no-stretching regimen (RNS) and 2 tests following a stretching regimen (RST). For experiment 1, when exercise was performed at 60% of body weight, stretching significantly (p < 0.05) reduced muscle strength endurance by 24%, and at 40% of body weight, it was reduced by 9%. For experiment 2, reliability was high (RNS, intraclass correlation = 0.94; RST, intraclass correlation = 0.97). Stretching also significantly (p < 0.05) reduced muscle strength endurance by 28%. Therefore, it is recommended that heavy static stretching exercises of a muscle group be avoided prior to any performances requiring maximal muscle strength endurance.
This study investigated the influence of static stretching exercises on specific exercise performances.
Thirty-eight volunteers participated in this study. The stretching group (STR) consisted of 8 males and 11 females whose activity was limited to a 10-wk, 40-min, 3-d.wk(-1) static stretching routine designed to stretch all the major muscle groups in the lower extremity. The control group (CON) consisted of 8 males and 11 females who did not participate in any kind of regular exercise routine during the study. Each subject was measured before and after for flexibility, power (20-m sprint, standing long jump, vertical jump), strength (knee flexion and knee extension one-repetition maximum (1RM)), and strength endurance (number of repetitions at 60% of 1RM for both knee flexion and knee extension).
STR had significant average improvements (P < 0.05) for flexibility (18.1%), standing long jump (2.3%), vertical jump (6.7%), 20-m sprint (1.3%), knee flexion 1RM (15.3%), knee extension 1RM (32.4%), knee flexion endurance (30.4%) and knee extension endurance (28.5%). The control group showed no improvement.
This study suggests that chronic static stretching exercises by themselves can improve specific exercise performances. It is possible that persons who are unable to participate in traditional strength training activities may be able to experience gains through stretching, which would allow them to transition into a more traditional exercise regimen.