Regional and widespread pain sensitivity decreases following stretching in both men and women - Indications of stretch-induced hypoalgesia.

INTRODUCTION: This study aimed to investigate the effect of sex on regional and widespread pain sensitivity following acute bouts of stretching and to investigate the acute effect of stretching on regional and widespread pain sensitivity following stretching. METHODS: 73 healthy adults (36 females; mean age 25.6 ± 6.7 years) with an age range from 19 to 62 years were recruited for this experimental study. Regional and distant pain pressure pain thresholds, passive knee extension range of motion and passive resistive torque were measured before and 30 s after four bouts of 30-s static muscle stretching of the knee flexors with 20-s rest between bouts. RESULTS: No significant sex differences were found for pressure pain thresholds (p > 0.132), range of motion (p = 0.446) or passive resistive torque (p = 0.559) between pre-stretch and post-stretch measures. There were significant increases in pressure pain thresholds (p = 0.010), range of motion (p = 0.001) and passive resistive torque (p = 0.007) between pre-stretch and post-stretch measures. CONCLUSION: Muscle stretching significantly decreased regional and widespread pain sensitivity, indicating that central pain-modulating mechanisms are engaged during muscle stretching, resulting in stretch-induced hypoalgesia. Moreover, the results showed that the effect of stretching on regional and widespread pain sensitivity is not sex-specific.

Effects of chronic static stretching interventions on jumping and sprinting performance-a systematic review with multilevel meta-analysis.

When improving athletic performance in sports with high-speed strength demands such as soccer, basketball, or track and field, the most common training method might be resistance training and plyometrics. Since a link between strength capacity and speed strength exists and recently published literature suggested chronic stretching routines may enhance maximum strength and hypertrophy, this review was performed to explore potential benefits on athletic performance. Based on current literature, a beneficial effect of static stretching on jumping and sprinting performance was hypothesized. A systematic literature search was conducted using PubMed, Web of Science and Google scholar. In general, 14 studies revealed 29 effect sizes (ES) (20 for jumping, nine for sprinting). Subgroup analyses for jump performance were conducted for short- long- and no stretch shortening cycle trials. Qualitative evaluation was supplemented by performing a multilevel meta-analysis via R (Package: metafor). Significant positive results were documented in six out of 20 jump tests and in six out of nine sprint tests, while two studies reported negative adaptations. Quantitative data analyses indicated a positive but trivial magnitude of change on jumping performance (ES:0.16, p = 0.04), while all subgroup analyses did not support a positive effect (p = 0.09-0.44). No significant influence of static stretching on sprint performance was obtained (p = 0.08). Stretching does not seem to induce a sufficient stimulus to meaningfully enhance jumping and sprinting performance, which could possibly attributed to small weekly training volumes or lack of intensity.

Effects of a Home-Based Stretching Program on Bench Press Maximum Strength and Shoulder Flexibility.

Recent research showed significant stretch-mediated maximum strength increases when performing stretching between 5 to 120 minutes per day with the calf muscle. However, since the practical applicability of these long stretching durations was questioned and studies exploring the transferability to the upper body are scarce, the aim of this study was to investigate the possibility of using a home-based stretching program to induce significant increases in maximum strength and flexibility. Therefore, 31 recreationally active participants (intervention group: 18, control group: 13) stretched the pectoralis major for 15min/day for eight weeks, incorporating three different stretching exercises. The maximum strength was tested isometrically and dynamically in the bench press (one-repetition maximum: 1RM) as well as shoulder range of motion (ROM) performing bilateral shoulder rotation with a scaled bar. Using a two-way analysis of variance (ANOVA) with repeated measures, the results showed high magnitude Time effects (ƞ² = 0.388-0.582, p < 0.001) and Group*Time interaction (ƞ² = 0.281-0.53, p < 0.001-0.002), with increases of 7.4 ± 5.6% in 1RM and of 9.8 ± 5.0% in ROM test in the intervention group. In the isometric testing, there was a high-magnitude Time effect (ƞ² = 0.271, p = 0.003), however, the Group*Time interaction failed to reach significance (p = 0.75). The results are in line with previous results that showed stretch-mediated maximum strength increases in the lower extremity. Future research should address the underlying physiological mechanisms such as muscle hypertrophy, contraction conditions as well as pointing out the relevance of intensity, training frequency and stretching duration.

Effects of a High-Volume 7-Week Pectoralis Muscle Stretching Training on Muscle Function and Muscle Stiffness.

BACKGROUND: There is evidence that high-volume static stretching training of the lower limbs can increase the range of motion (ROM) while decreasing muscles stiffness. However, to date, there is no evidence on the effects of upper limb stretching training or its effect mechanism. Therefore, this study aimed to investigate the effects of a comprehensive 7-week static stretching training program of the pectoralis major muscle (PMa) on glenohumeral joint ROM, muscle force, and muscle stiffness. METHODS: Thirty-eight healthy, physically active participants (23 male, 15 female) were randomly assigned to either the PMa-static stretching intervention (PMa-SS) group or the control group. The PMa-SS group performed a 7-week intervention comprising three sessions a week for 15 min per session, including three static stretching exercises of the PMa for 5 min each. Before and after the intervention period, shoulder extension ROM, muscle stiffness of the PMa (pars clavicularis), and maximal voluntary isometric contraction (MVIC) peak torque (evaluated at both long (MVIClong) and short (MVICshort) muscle lengths) were investigated on a custom-made testing device at 45° shoulder abduction. RESULTS: In the PMa-SS group, the shoulder extension ROM (+ 6%; p < 0.01; d = 0.92) and the MVIClong (+ 11%; p = 0.01; d = 0.76) increased. However, there were no significant changes in MVICshort or in PMa muscle stiffness in the PMa-SS group. In the control group, no changes occurred in any parameter. CONCLUSION: In addition to the increase in ROM, we also observed an improved MVIC at longer but not shorter muscle lengths. This potentially indicates an increase in fascicle length, and hence a likely increase in sarcomeres in series.

Effects of daily static stretch training over 6 weeks on maximal strength, muscle thickness, contraction properties, and flexibility.

Purpose: Static stretch training (SST) with long stretching durations seems to be sufficient to increase flexibility, maximum strength (MSt) and muscle thickness (MTh). However, changes in contraction properties and effects on muscle damage remain unclear. Consequently, the objective of the study was to investigate the effects of a 6-week self-performed SST on MSt, MTh, contractile properties, flexibility, and acute response of creatine kinase (CK) 3 days after SST. Methods: Forty-four participants were divided into a control (CG, n = 22) and an intervention group (IG, n = 22), who performed a daily SST for 5 min for the lower limb muscle group. While isometric MSt was measured in leg press, MTh was examined via sonography and flexibility by functional tests. Muscle stiffness and contraction time were measured by tensiomyography on the rectus femoris. Additionally, capillary blood samples were taken in the pretest and in the first 3 days after starting SST to measure CK. Results: A significant increase was found for MSt (p < 0.001, η 2 = 0.195) and flexibility in all functional tests (p < 0.001, η 2 > 0.310). Scheffé post hoc test did not show significant differences between the rectus femoris muscle inter- and intragroup comparisons for MTh nor for muscle stiffness and contraction time (p > 0.05, η 2 < 0.100). Moreover, CK was not significantly different between IG and CG with p > 0.05, η 2 = 0.032. Discussion: In conclusion, the increase in MSt cannot be exclusively explained by muscular hypertrophy or the increased CK-related repair mechanism after acute stretching. Rather, neuronal adaptations have to be considered. Furthermore, daily 5-min SST over 6 weeks does not seem sufficient to change muscle stiffness or contraction time. Increases in flexibility tests could be attributed to a stretch-induced change in the muscle-tendon complex.

Alternative Flexibility Training.

Over the last approximately 20 years, research has reported on performance impairments following prolonged durations of static stretching. This has led to a paradigm shift towards dynamic stretching. There has also been a greater emphasis using foam rollers, vibration devices, and other techniques. Recent commentaries and meta-analyses suggest that stretching need not be listed as a fitness component as other activities such as resistance training can provide similar range of motion benefits. The commentary aims to review and compare the effects of static stretching and alternative exercises for improving range of motion.

Instrument-Assisted Soft Tissue Mobilization Technique versus Static Stretching in Patients with Pronated Dominant Foot: A Comparison in Effectiveness on Flexibility, Foot Posture, Foot Function Index, and Dynamic Balance.

BACKGROUND: Pronated foot is a deformity with various degrees of physical impact. Patients with a pronated foot experience issues such as foot pain, ankle pain, heel pain, shin splints, impaired balance, plantar fasciitis, etc. Objective: The study intended to compare the effectiveness of IASTM (instrument-assisted soft tissue mobilization) and static stretching on ankle flexibility, foot posture, foot function, and balance in patients with a flexible pronated foot. METHODS: Seventy-two participants between the ages of 18-25 years with a flexible pronated foot were included and allocated into three groups: Control, stretching, and IASTM group using single-blinded randomization. Range of motion (ROM) measuring ankle flexibility, foot posture index (FPI), foot function index (FFI), and dynamic balance was measured at baseline and after 4 weeks of intervention. Soft tissue mobilization was applied on to the IASTM group, while the stretching group was directed in static stretching of the gastrocnemius-soleus complex, tibialis anterior, and Achilles tendon in addition to the foot exercises. The control group received only foot exercises for 4 weeks. RESULTS: The result shows the significant improvement of the right dominant foot in ROM plantar flexion, (F = 3.94, p = 0.03), dorsiflexion (F = 3.15, p = 0.05), inversion (F = 8.54, p = 0.001) and eversion (F = 5.93, p = 0.005), FFI (control vs. IASTM, mean difference (MD) = 5.9, p < 0.001), FPI (right foot, control vs. IASTM MD = 0.88, p = 0.004), and in dynamic balance of the right-leg stance (anterior, pre vs. post = 88.55 ± 2.28 vs. 94.65 ± 2.28; anteromedial, pre vs. post = 80.65 ± 2.3 vs. 85.55 ± 2.93; posterior, pre vs. post = 83 ± 3.52 vs. 87 ± 2.99 and lateral, pre vs. post = 73.2 ± 5.02 vs. 78.05 ± 4.29) in the IASTM group. The FFI was increased remarkably in the stretching group as compared to the control group. CONCLUSIONS: Myofascial release technique, i.e., IASTM with foot exercises, significantly improves flexibility, foot posture, foot function, and dynamic balance as compared to stretching, making it a choice of treatment for patients with a flexible pronated foot.

Effects of Different Recovery Modalities on Delayed Onset Muscle Soreness, Recovery Perceptions, and Performance Following a Bout of High-Intensity Functional Training.

The purpose of this study was to investigate the effects of the foam rolling technique and static stretching on perceptual and neuromuscular parameters following a bout of high-intensity functional training (HIFT), which consisted of 100 pull-ups, 100 push-ups, 100 sit-ups, and 100 air squats (Angie benchmark) in recreationally trained men (n = 39). Following baseline measurements (Feeling Scale, Visual Analogue Scale, Total Quality Recovery, Sit-and-Reach, Countermovement Jump, and Change-of-Direction t-test), the volunteers performed a single bout of HIFT. At the end of the session, participants were randomly assigned to one of three distinct groups: control (CONT), foam rolling (FR), or static stretching (SS). At the 24 h time-point, a second experimental session was conducted to obtain the post-test values. The level of significance was set at p < 0.05. Regarding power performance, none of the three groups reached pretest levels at 24 h point of the intervention. However, the CONT group still showed a greater magnitude of effect at the 24 h time-point (ES = 0.51, p ≥ 0.05). Flexibility presented the same recovery pattern as power performance (post × 24 h CONT = ES = 0.28, FR = ES = 0.21, SS = ES = 0.19). At 24 h, all groups presented an impaired performance in the COD t-test (CONT = ES = 0.24, FR = ES = 0.65, SS = ES = 0.56 p ≥ 0.05). The FR protocol resulted in superior recovery perceptions (pre × 24 h TQR = ES = 0.32 p ≥ 0.05). The results of the present study indicate that the use of FR and SS exercises may not be indicated when aiming to restore neuromuscular performance following a single bout of HIFT. The use of the FR technique during the cooldown phase of a HIFT session may be helpful in improving an individual's perception of recovery.

Effects of Plantar Flexor Stretching on Static and Dynamic Balance in Healthy Adults.

Stretching can affect balance ability by generating biomechanical and physiological changes in the postural muscles. Stretching of the lower extremity muscles can greatly affect posture maintenance strategies and balance ability. However, the relationship between stretching and balance ability has not been clarified. Therefore, this study aimed to investigate the effect of plantar flexor stretching on balance ability. Forty-four healthy young adults were randomly assigned to four groups (static stretching, dynamic stretching, ballistic stretching, and control). Ankle joint range of motion, static balance ability, and dynamic balance ability were evaluated before, immediately after, and 20 min after stretching. Stretching did not affect balance ability in the open-eye condition. After stretching, the sway area was significantly reduced in the closed-eye condition (p < 0.05). After stretching, the reach distance of dynamic balance ability increased significantly (p < 0.05). The results show that plantar flexor stretching can positively affect balance ability. Therefore, plantar flexor stretching should be considered a rehabilitation method to improve balance.

The Effects of Static Stretching On Dynamic Postural Control During Maximum Forward Leaning Task.

The purpose of this study was to determine how the application of static stretching to ankle plantar flexors affects postural control during maximum forward leaning. Twenty-six volunteer males (age 21.4 ± 1.2 years) were randomly assigned to stretching and control conditions. Participants conducted 5-min stretching on a stretch board for the stretching condition and were kept standing for 6-min for the control condition. Before and after intervention, the range of motion (ROM) at ankle dorsiflexion and the center of pressure (COP) excursion during maximal forward leaning were determined. Mean anteroposterior COP position, COP velocity and COP areas were calculated to compare the change in postural control. After stretching, ROM was significantly increased. During maximal forward leaning after stretching, both COP position and velocity showed significant increases compared to before stretching. Moreover, COP position and velocity in the stretching condition were significantly higher than in the control condition after stretching. No significant differences were found in COP area before and after stretching. Five-minute stretching increased not only ROM but also the anterior limit of stability while maintaining posture and led to faster COP shift than before stretching. These results indicate that static stretching would improve dynamic postural control as well.

A cognitive task, deep breathing, and static stretching reduce variability of motor evoked potentials during subsequent transcranial magnetic stimulation.

BACKGROUND: Motor evoked potentials (MEPs) induced via transcranial magnetic stimulation (TMS) demonstrate trial-to-trial variability limiting detection and interpretation of changes in corticomotor excitability. This study examined whether performing a cognitive task, voluntary breathing, or static stretching before TMS could reduce MEP variability. METHODS: 20 healthy young adults performed no-task, a cognitive task (Stroop test), deep breathing, and static stretching before TMS in a randomized order. MEPs were collected in the non-dominant tibialis anterior muscle at 130% active motor threshold. Variability of MEP amplitude was quantified as coefficient of variation (CV). RESULTS: MEP CV was greater after no-task (25.4 ± 7.0) than after cognitive task (23.3 ± 7.2; p < 0.05), deep breathing (20.1 ± 6.3; p < 0.001), and static stretching (20.9 ± 6.0; p = 0.004). MEP CV was greater after cognitive task than after deep breathing (p = 0.007) and static stretching (p = 0.01). There was no effect of condition on MEP amplitude. CONCLUSIONS: Performing brief cognitive, voluntary breathing, and stretching tasks before TMS can reduce MEP variability with no effect on MEP amplitude in the tibialis anterior of healthy, young adults. Similar tasks could be incorporated into research and clinical settings to improve detection of changes, normative data, and clinical predictions.

Acute effect of diagonal stretching using the posterior oblique sling system on contralateral ankle dorsiflexion.

BACKGROUND: A significant increase in the dorsiflexion range of motion (DFROM) after calf muscle stretching has been widely studied. However, it has been shown that the upper body is connected to the ankle joint by passive connective tissues. OBJECTIVE: The purpose of this study was to examine the effect of upper-back stretching on the mobility of the contralateral ankle. METHODS: In the supine position, DFROM in the contralateral leg was measured. In the sitting position with and without trunk rotation, DFROM was measured in both legs. In the sitting position with trunk rotation, dorsiflexion was measured only in the contralateral leg. Static diagonal stretching combining trunk rotation with slight trunk flexion was performed in the sitting position with a neutral pelvis. RESULTS: After stretching, DFROM in contralateral and ipsilateral legs were measured in the sitting position with a neutral pelvis. In the contralateral leg, significant differences in ΔDFROM were observed between the sitting position with trunk rotation and the supine position and between the sitting position with trunk rotation and the sitting position after stretching. CONCLUSION: In clinical settings, diagonal stretching of the unilateral posterior trunk causes a significant increase in the DFROM of the contralateral lower limb.

Comparison Between the Effects of Transfer Energy Capacitive and Resistive Therapy and Therapeutic Ultrasound on Hamstring Muscle Shortness in Male Athletes: A Single-Blind Randomized Controlled Trial.

BACKGROUND: Transfer energy capacitive and resistive (TECAR) therapy (TT) is a newly developed deep heating therapy that can generate heat within tissues through high-frequency wave stimulation. Compared to conventional physiotherapy methods, the application of TT especially in sports rehabilitation is becoming more popular. This study aimed to investigate the comparative effect of TT and therapeutic ultrasound (US) on hamstring muscle shortness. Additionally, the effects of TT with static stretching (SS) were compared with US combined with SS. MATERIALS AND METHODS: Totally, 39 male athletes with hamstring shortness were randomly assigned into three groups: A, B, and C. Group A received 15 minutes of TT plus SS, while Group B received 15 minutes of US with SS, and Group C only performed SS. Hamstring flexibility was measured by active knee extension (AKE), passive knee extension (PKE), and the sit and Reach (SR) tests before the intervention, and following the first, and third treatment sessions. RESULTS: The range of motion of the AKE and PKE, and displacement range in the SR test improved significantly after the first and third sessions in all three groups (P0.0001). The improvement of the three flexibility indices in the TT group was greater than in the other two groups. CONCLUSION: The present study showed that TT could increase the flexibility of hamstring muscles more than US therapy. However, TT in combination with SS had a similar effect to SS alone.

A Comparison of the Acute Effects of Percussion Massage Therapy and Static Stretching on Hamstring Elasticity.

Background: The effect of percussion massage on hamstring flexibility is unknown. This study aimed to investigate the acute effects of percussion massage on hamstring flexibility and to compare its effectiveness with static stretching. Methods: Fifty-four healthy individuals aged 18-25 years with at least 15 degrees of active knee extension were included in the study. The study was conducted between February and May 2022. The participants were randomly divided into 3 groups in this cross-randomization study as percussion massage (n=18), static stretching (n=18), and control (n=18). The Active Knee Extension test and the Sit and Reach test were used as evaluation parameters, and assessments were performed pre-intervention and 30 min post-intervention (acute). Results: In both percussion and stretching intervention groups, the range of motion (ROM) gain in the Active Knee Extension test was statistically significant (p<0.05) compared to the control group. Active knee extension angle gain was similar between percussion and stretching interventions (p>0.05). It was found that hamstring flexibility improved significantly in both percussion massage and static stretching groups (p<0.05). However, considering the last measurement and flexibility gain values, it was found that percussion massage and static stretching had similar acute effects on hamstring muscle flexibility (p>0.05). Conclusion: Percussion massage had an acute positive effect on hamstring flexibility and ROM, and it was as effective as static stretching. Therefore, percussion massage devices are recommended as part of pre-exercise in a structured warm-up for increase in joint range of motion and flexibility.

Effects of Dynamic Stretching Combined with Manual Therapy on Pain, ROM, Function, and Quality of Life of Adhesive Capsulitis.

This study was conducted to evaluate the effects of dynamic stretching combined with manual therapy on pain, range of motion, function, and quality of life in patients with adhesive capsulitis. The participants were randomly divided into two groups: the dynamic stretching combined with manual therapy (DSMT) group (n = 17) and the static stretching combined with manual therapy (SSMT) group (n = 17). Both groups received manual therapy for 10 min and two sessions per week for 4 weeks. The DSMT group also performed additional dynamic stretching for 20 min per session, two sessions per week for 4 weeks. The SSMT group practiced additional static stretching for 20 min per session, two sessions per week for 4 weeks. The pain, ROM, function, and quality of life were measured and evaluated before and after treatment. There were significant improvements in the outcomes of pain, flexion and abduction of shoulder ROM, Shoulder Pain and Disability Index (SPADI), and the physical component score and mental component score of the Short Form-36 (SF-36) in both groups. Additionally, the external and internal rotation of the shoulder ROM and the SF-36 general health factor increased significantly more in the A group (DSMT group) compared to the B group (SSMT). In conclusion, dynamic stretching plus manual therapy offers the same results as static stretching plus manual therapy, but with additional improvement in internal and external rotation.

Acute Effects of Different Intensity and Duration of Static Stretching on the Muscle-Tendon Unit Stiffness of the Hamstrings.

The effects of static stretching are influenced by prescribed and applied loads of stretching. The prescribed load is calculated from the stretching duration and intensity, whereas the applied load is assessed from the force of static stretching exerted on the targeted muscle. No previous study has investigated the prescribed and applied loads of static stretching on the muscle-tendon unit stiffness simultaneously. Therefore, the purpose of the present study was to examine the acute effects of the prescribed and applied load of static stretching on the change in the muscle-tendon unit stiffness of the hamstrings by using different intensities and durations of static stretching. Twenty-three participants underwent static stretching at the intensity of high (50 seconds, 3 sets), moderate (60 seconds, 3 sets), and low (75 seconds, 3 sets), in random order. The parameters were the range of motion, passive torque, and muscle-tendon unit stiffness. These parameters were measured before stretching, between sets, and immediately after stretching by using a dynamometer machine. The static stretching load was calculated from the passive torque during static stretching. The muscle-tendon unit stiffness decreased in high- and moderate-intensity after 50 (p < 0.01, d = -0.73) and 180 seconds (p < 0.01, d = -1.10) of stretching respectively, but there was no change in low-intensity stretching for 225 seconds (p = 0.48, d = -0.18). There were significant correlations between the static stretching load and relative change in the muscle-tendon unit stiffness in moderate- (r = -0.64, p < 0.01) and low-intensity (r = -0.54, p < 0.01), but not in high-intensity (r = -0.16, p = 0.18). High-intensity static stretching was effective for a decrease in the muscle-tendon unit stiffness even when the prescribed load of static stretching was unified. The applied load of static stretching was an important factor in decreasing the muscle-tendon unit stiffness in low- and moderate-intensity static stretching, but not in high-intensity stretching.

Effects of stretching intensity on range of motion and muscle stiffness: A narrative review.

BACKGROUND: No review has yet investigated acute and chronic effects of different stretching intensities, including constant-angle (CA) and constant-torque (CT) stretching. OBJECTIVE: This review aimed to investigate the acute and chronic effects of different stretching intensities on the range of motion (ROM) and passive properties. METHODS: PubMed, Scopus, and Google Scholar were used for literature search. Advanced search functions were used to identify original studies using the terms stretching intensity, constant-torque stretching, constant-angle stretching, ROM, passive stiffness, shear elastic modulus in the title or abstract. The keywords were combined using the Boolean operators "AND" and "OR". The search for articles published from inception until 2021 was done in electronic databases. RESULTS AND CONCLUSION: Five studies compared CA and CT stretching. Three studies reported a greater decrease in passive stiffness, and two studies reported a greater ROM increase after CT than CA stretching. Twelve studies investigated the acute effects of different stretching intensities, and six reported a greater ROM increase at higher stretching intensities. Five studies reported a greater decrease in passive stiffness at higher stretching intensities, but three reported no significant differences in passive stiffness among stretching intensities. Five studies investigated the chronic effect, and four reported no significant difference in ROM change among different intensities. Three studies reported no significant changes in passive stiffness after the stretching program. We suggest that the acute effect of higher stretching intensity, including CT stretching, was more effective for changes in ROM and passive stiffness, but the chronic effect was weak.

Changes in stiffness of the specific regions of knee extensor mechanism after static stretching.

Decreased muscle stiffness could reduce musculotendinous injury risk in sports and rehabilitation settings. Static stretching (SS) has been used to increase the flexibility of muscles and reduce muscle stiffness, but the effects of SS on the stiffness of specific regions of the knee extensor mechanism are unclear. The quadriceps femoris and patellar tendon are essential components of the knee extensor mechanism and play an important role in knee motion. Therefore, we explored the acute and prolonged effects of SS on the stiffness of the quadriceps femoris and patellar tendon and knee flexion range of motion (ROM). Thirty healthy male subjects participated in the study. Three 60-s SS with 30-s intervals were conducted in right knee flexion with 30° hip extension. We measured the ROM and stiffness of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) and the proximal-(PPT), middle-(MPT), and distal-(DPT) region stiffness of the patellar tendon before and immediately after SS intervention, or 5 and 10 min after SS. The stiffness of the quadriceps muscle and patellar tendon were measured using MyotonPRO, and the knee flexion ROM was evaluated using a medical goniometer. Our outcomes showed that the ROM was increased after SS intervention in all-time conditions (p < 0.01). Additionally, the results showed that the stiffness of RF (p < 0.01) and PPT (p = 0.03) were decreased immediately after SS intervention. These results suggested that SS intervention could be useful to increase knee flexion ROM and temporarily reduce the stiffness of specific regions of the knee extensor mechanism.

Acute effect of inhibitory kinesio tape on range of motion, dynamic balance, and gait in athletes with hamstring shortness.

OBJECTIVE: The goal of the present study was to investigate the acute effects of kinesio tape on range of motion (ROM), perceived stiffness, and kinetic parameters in athletes with hamstring shortness. METHODS: Fifteen athletes with bilateral hamstring shortness were divided randomly into intervention (inhibitory application of kinesio tape plus static stretching) and control (static stretching) groups. Outcome measures were straight leg raise (SLR), active knee extension (AKE) tests for ROM, visual analogue scale (VAS) for perceived stiffness and kinetic parameters which are recorded and calculated by Moticon SCIENCE insoles during four functional performance task of single leg stance (SLS), slow and fast walking and running. RESULTS: ROM, stiffness, and kinetic parameters examined with insoles during SLS and walking tasks changed in both the intervention and control groups (P < 0.05). Furthermore, study groups were different in some variables. The increase in ROM in SLR test and the decrease in perceived stiffness in the intervention group were more evident than in the control group (P = 0.03 and P = 0.001, respectively). There was no difference between the intervention and control groups for the variables in SLS test, slow and fast walking, and running tasks, except for the mean swing duration (MSWD) (P = 0.002) in fast walking. CONCLUSION: The static stretching alone and the kinesio tape plus static stretching could change many of the kinetic parameters during walking and balance tasks, but the rate of these changes were more significant with kinesio tape plus stretching compared to the stretching alone.

Influence of Long-Lasting Static Stretching on Maximal Strength, Muscle Thickness and Flexibility.

Background: In animal studies long-term stretching interventions up to several hours per day have shown large increases in muscle mass as well as maximal strength. The aim of this study was to investigate the effects of a long-term stretching on maximal strength, muscle cross sectional area (MCSA) and range of motion (ROM) in humans. Methods: 52 subjects were divided into an Intervention group (IG, n = 27) and a control group (CG, n = 25). IG stretched the plantar flexors for one hour per day for six weeks using an orthosis. Stretching was performed on one leg only to investigate the contralateral force transfer. Maximal isometric strength (MIS) and 1RM were both measured in extended knee joint. Furthermore, we investigated the MCSA of IG in the lateral head of the gastrocnemius (LG) using sonography. Additionally, ROM in the upper ankle was investigated via the functional "knee to wall stretch" test (KtW) and a goniometer device on the orthosis. A two-way ANOVA was performed in data analysis, using the Scheffé Test as post-hoc test. Results: There were high time-effects (p = 0.003, ƞ² = 0.090) and high interaction-effect (p < 0.001, ƞ²=0.387) for MIS and also high time-effects (p < 0.001, ƞ²=0.193) and interaction-effects (p < 0.001, ƞ²=0,362) for 1RM testing. Furthermore, we measured a significant increase of 15.2% in MCSA of LG with high time-effect (p < 0.001, ƞ²=0.545) and high interaction-effect (p=0.015, ƞ²=0.406). In ROM we found in both tests significant increases up to 27.3% with moderate time-effect (p < 0.001, ƞ²=0.129) and high interaction-effect (p < 0.001, ƞ²=0.199). Additionally, we measured significant contralateral force transfers in maximal strength tests of 11.4% (p < 0.001) in 1RM test and 1.4% (p=0.462) in MIS test. Overall, there we no significant effects in control situations for any parameter (CG and non-intervened leg of IG). Discussion: We hypothesize stretching-induced muscle damage comparable to effects of mechanical load of strength training, that led to hypertrophy and thus to an increase in maximal strength. Increases in ROM could be attributed to longitudinal hypertrophy effects, e.g., increase in serial sarcomeres. Measured cross-education effects could be explained by central neural adaptations due to stimulation of the stretched muscles.