Crossover Effects of Unilateral Static Stretching and Foam Rolling on Contralateral Hamstring Flexibility and Strength

Foam rolling and stretching do not provide superior acute flexibility and stiffness improvements compared to any other warm-up intervention: A systematic review with meta-analysis

BACKGROUND

Acute improvement in range of motion (ROM) is a widely reported effect of stretching and foam rolling, which is commonly explained by changes in pain threshold and/or musculotendinous stiffness. Interestingly, these effects were also reported in response to various other active and passive interventions that induce responses such as enhanced muscle temperature. Therefore, we hypothesized that acute ROM enhancements could be induced by a wide variety of interventions other than stretching or foam rolling that promote an increase in muscle temperature.

METHODS

After a systematic search in PubMed, Web of Science, and SPORTDiscus databases, 38 studies comparing the effects of stretching and foam rolling with several other interventions on ROM and passive properties were included. These studies had 1134 participants in total, and the data analysis resulted in 140 effect sizes (ESs). ES calculations were performed using robust variance estimation model with R-package.

RESULTS

Study quality of the included studies was classified as fair (PEDro score = 4.58) with low to moderate certainty of evidence. Results showed no significant differences in ROM (ES = 0.01, p = 0.88), stiffness (ES = 0.09, p = 0.67), or passive peak torque (ES = -0.30, p = 0.14) between stretching or foam rolling and the other identified activities. Funnel plots revealed no publication bias.

CONCLUSION

Based on current literature, our results challenge the established view on stretching and foam rolling as a recommended component of warm-up programs. The lack of significant difference between interventions suggests there is no need to emphasize stretching or foam rolling to induce acute ROM, passive peak torque increases, or stiffness reductions.

Discussing Conflicting Explanatory Approaches in Flexibility Training Under Consideration of Physiology: A Narrative Review

The mechanisms underlying range of motion enhancements via flexibility training discussed in the literature show high heterogeneity in research methodology and study findings. In addition, scientific conclusions are mostly based on functional observations while studies considering the underlying physiology are less common. However, understanding the underlying mechanisms that contribute to an improved range of motion through stretching is crucial for conducting comparable studies with sound designs, optimising training routines and accurately interpreting resulting outcomes. While there seems to be no evidence to attribute acute range of motion increases as well as changes in muscle and tendon stiffness and pain perception specifically to stretching or foam rolling, the role of general warm-up effects is discussed in this paper. Additionally, the role of mechanical tension applied to greater muscle lengths for range of motion improvement will be discussed. Thus, it is suggested that physical training stressors can be seen as external stimuli that control gene expression via the targeted stimulation of transcription factors, leading to structural adaptations due to enhanced protein synthesis. Hence, the possible role of serial sarcomerogenesis in altering pain perception, reducing muscle stiffness and passive torque, or changes in the optimal joint angle for force development is considered as well as alternative interventions with a potential impact on anabolic pathways. As there are limited possibilities to directly measure serial sarcomere number, longitudinal muscle hypertrophy remains without direct evidence. The available literature does not demonstrate the necessity of only using specific flexibility training routines such as stretching to enhance acute or chronic range of motion.

Effects of foam rolling on hamstrings stiffness in damaged and non-damaged muscle states

Introduction: The aim of this study was to examine the effects of foam rolling (FR) on hamstring muscles stiffness in both non-damaged and exercise-induced muscle damage (EIMD) states, using shear wave ultrasound elastography to measure changes in shear modulus. Methods: Fourteen healthy adults (25.5 ± 4.7 years) participated in a within-participant repeated measures design, with a 2-minute FR intervention applied on one leg and contralateral leg serving as a control. The damaging protocol encompassed maximal eccentric knee extensions performed on an isokinetic dynamometer and the Nordic hamstring exercise, consisting of 3 sets of 10 and 6 repetitions, respectively. Measurement were taken at baseline and then 1 h, 24 h and 48 h after the damaging protocol. Results: The results indicated no significant time × leg interaction for shear modulus in biceps femoris, semimembranosus, and semitendinosus muscles in both non-damaged and damaged states. Notably, there was a significant increase in biceps femoris (p = 0.001; η2 = 0.36) and semitendinosus (p < 0.001; η2 = 0.44) shear modulus after EIMD, but no significant differences were found between the FR and control leg, which was also the case for muscle soreness, range of motion, and passive resistive torque (p = 0.239-0.999 for interactions). Discussion: The absence of significant changes post-FR intervention suggests a limited role of short-duration FR in altering muscle stiffness during recovery from EIMD. These findings contribute to the understanding of FR's role in muscle recovery. Although this was not directly investigated, our results suggest a predominance of central mechanisms rather than direct mechanical modifications in muscle properties. This research highlights the necessity for additional investigations to explore how FR interventions influence muscles in different states and to elucidate the mechanisms underlying these influences.

Acute effects of different administration order of stretching exercises: effects on range of motion and cross-over effect

BACKGROUND

The aim of this manuscript is to investigate if stretching exercise administration order may influence outcomes pertinent to range of movement (ROM).

METHODS

A total sample of 108 participants was randomized into five groups. Eight sets of unilateral static stretching (SS) of 30s duration each with a 30s rest were administered to the right leg. One group underwent SS of the knee extensors (KE), another to the knee flexors (KF), another first to the KE and then to the KF, another first to the KF and then to the KE while the last group was used as control (CG). Each group was assessed for ROM of both lower limbs for either the KE and KF motion (passive hip extention [PHE] and passive straight leg raise [PSLR], respectively). Measures were assessed before (T0), immediately after (T1), and 15 minutes after the intervention (T2).

RESULTS

No differences were observed for time (T0 vs. T1 vs. T2) for all measures in the CG for both limbs. Time-x-group interactions were observed only in the intervention limb (P<0.0007 and 0.004, ES 0.73 and 0.55, for KE and KF, respectively). Within the intervention limb, a significant increase in the PHE was observed from T0 to T1 only in the KE and KF/KE groups. For measures of the PSLR, a significant increase was observed from T0 to T1 only in the KF and KE/KF groups. No differences neither for time or group were observed in the control limb.

CONCLUSIONS

Our results highlight that exercise administration order has an effect on ROM outcomes. Measures of ROM significantly increase only for the last stretched muscle in each intervention group. No crossover effect was observed in the contralateral limb.

Corticospinal excitability and reflex modulation in a contralateral non-stretched muscle following unilateral stretching

PURPOSE

Muscle stretching effect on the range of motion (ROM) and force deficit in non-stretched muscle, and the underlying mechanisms, is an ongoing issue. This study aimed to investigate crossover stretching effects and mechanisms on the plantar flexor muscles.

METHODS

Fourteen recreationally active females (n = 5) and males (n = 9) performed six sets of 45-s static stretching (SS) (15-s recovery) to the point of discomfort of the dominant leg (DL) plantar flexors or control (345-s rest). Participants were tested for a single 5-s pre- and post-test maximal voluntary isometric contraction (MVIC) with each plantar flexor muscle and were tested for DL and non-DL ROM. They were tested pre- and post-test (immediate, 10-s, 30-s) for the Hoffman (H)-reflex and motor-evoked potentials (MEP) from transcranial magnetic stimulation in the contralateral, non-stretched muscle.

RESULTS

Both the DL and non-DL-MVIC force had large magnitude, significant (↓10.87%, p = 0.027, pƞ2 = 0.4) and non-significant (↓9.53%, p = 0.15, pƞ2 = 0.19) decreases respectively with SS. The SS also significantly improved the DL (6.5%, p < 0.001) and non-DL (5.35%, p = 0.002) ROM. The non-DL MEP/MMax and HMax/MMax ratio did not change significantly.

CONCLUSION

Prolonged static stretching improved the stretched muscle's ROM. However, the stretched limb's force was negatively affected following the stretching protocol. The ROM improvement and large magnitude force impairment (statistically non-significant) were transferred to the contralateral muscles. The lack of significant changes in spinal and corticospinal excitability confirms that the afferent excitability of the spinal motoneurons and corticospinal excitability may not play a substantial role in non-local muscle's ROM or force output responses.

The contralateral effects of foam rolling on range of motion and muscle performance

A single bout of foam rolling (FR) can acutely increase joint range of motion (ROM) without detrimental effects on subsequent muscle performance. Similarly, long-term FR training can increase ROM, while muscle performance seems to be unaffected. Although the acute and long-term effects of FR on the treated muscle are understood, the impact of FR on the contralateral side is not well known. Therefore, this scoping review aims to summarize the current evidence on the acute and long-term effect of FR on the ipsilateral limb on ROM and muscle performance (i.e., maximum force, rate of force development, jump height) for the contralateral (non-treated) limb. Potential explanatory mechanisms are also discussed. There is evidence that a single bout of FR on the ipsilateral limb increases ROM of the contralateral limb; however, evidence is limited for long-term effects. The most likely mechanism for contralateral ROM increases is a reduced perception of pain. With regard to isolated muscle contractions, no changes in muscle performance (i.e., maximum voluntary isometric contraction, maximum voluntary dynamic contraction) were found in the contralateral limb after a single bout of FR on the ipsilateral limb. Notably, only one study reported large impairments in rate of force development of the contralateral limb following FR on the ipsilateral leg, possibly due to decreased motor unit recruitment. Furthermore, to date there are only two studies examining the long-term FR training of the ipsilateral limb on performance (i.e., maximal strength and jump performance) which reported moderate improvements. Although, trivial to very large changes on a variety of parameters were found in this study, the functional and practical relevance of our findings should be interpreted with caution.

Are Acute Effects of Foam-Rolling Attributed to Dynamic Warm Up Effects? A Comparative Study

Over the last decade, acute increases in range of motion (ROM) in response to foam rolling (FR) have been frequently reported. Compared to stretching, FR-induced ROM increases were not typically accompanied by a performance (e.g., force, power, endurance) deficit. Consequently, the inclusion of FR in warm-up routines was frequently recommended, especially since literature pointed out non-local ROM increases after FR. However, to attribute ROM increases to FR it must be ensured that such adaptations do not occur as a result of simple warm-up effects, as significant increases in ROM can also be assumed as a result of active warm-up routines. To answer this research question, 20 participants were recruited using a cross-over design. They performed 4x45 seconds hamstrings rolling under two conditions; FR, and sham rolling (SR) using a roller board to imitate the foam rolling movement without the pressure of the foam rolling. They were also tested in a control condition. Effects on ROM were tested under passive, active dynamic as well as ballistic conditions. Moreover, to examine non-local effects the knee to wall test (KtW) was used. Results showed that both interventions provided significant, moderate to large magnitude increases in passive hamstrings ROM and KtW respectively, compared to the control condition (p = 0.007-0.041, d = 0.62-0.77 and p = 0.002-0.006, d = 0.79-0.88, respectively). However, the ROM increases were not significantly different between the FR and the SR condition (p = 0.801, d = 0.156 and p = 0.933, d = 0.09, respectively). No significant changes could be obtained under the active dynamic (p = 0.65) while there was a significant decrease in the ballistic testing condition with a time effect (p < 0.001). Thus, it can be assumed that potential acute increases in ROM cannot be exclusively attributed to FR. It is therefore speculated that warm up effects could be responsible independent of FR or imitating the rolling movement, which indicates there is no additive effect of FR or SR to the dynamic or ballistic range of motion.

The Effects of Massage Therapy on Sport and Exercise Performance: A Systematic Review

BACKGROUND

A massage is a tool that is frequently used in sports and exercise in general for recovery and increased performance. In this review paper, we aimed to search and systemize current literature findings relating to massages' effects on sports and exercise performance concerning its effects on motor abilities and neurophysiological and psychological mechanisms.

METHODS

The review has been written following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analysis) guidelines. One hundred and fourteen articles were included in this review.

RESULTS

The data revealed that massages, in general, do not affect motor abilities, except flexibility. However, several studies demonstrated that positive muscle force and strength changed 48 h after the massage was given. Concerning neurophysiological parameters, the massage did not change blood lactate clearance, muscle blood flow, muscle temperature, or activation. However, many studies indicate pain reduction and delayed onset muscle soreness, which are probably correlated with the reduction of the level of creatine kinase enzyme and psychological mechanisms. In addition, the massage treatment led to a decrease in depression, stress, anxiety, and the perception of fatigue and an increase in mood, relaxation, and the perception of recovery.

CONCLUSION

The direct usage of massages just for gaining results in sport and exercise performance seems questionable. However, it is indirectly connected to performance as an important tool when an athlete should stay focused and relaxed during competition or training and recover after them.

The Soft Prefabricated Orthopedic Insole Decreases Plantar Pressure during Uphill Walking with Heavy Load Carriage

This study aimed to investigate the effect of varying the hardness of prefabricated orthopedic insoles on plantar pressure and muscle fatigue during uphill walking with a heavy backpack. Fifteen healthy male recreational athletes (age: 20.4 ± 1.0 years, height: 176.9 ± 5.7 cm, weight: 76.5 ± 9.0 kg) wore prefabricated orthopedic insoles with foot arch support; a heel cup with medium (MI), hard (HI), and soft (SI) relative hardnesses; and flat insoles (FI). They performed treadmill walking on uphill gradients with 25 kg backpacks. The plantar pressure and surface electromyographic activity were recorded separately, in 30 s and 6 min uphill treadmill walking trials, respectively. The HI, MI, and SI significantly decreased peak plantar pressure in the lateral heel compared to FI. The MI and SI significantly decreased the peak plantar pressure in the fifth metatarsal compared to FI. The MI significantly reduced the pressure–time integral in the lateral heel compared to FI. The HI significantly increased the peak plantar pressure and pressure–time integral in the toes compared to other insoles, and decreased the contact area in the metatarsal compared to SI. In conclusion, a prefabricated orthopedic insole made of soft material at the fore- and rearfoot, with midfoot arch support and a heel cup, may augment the advantages of plantar pressure distribution during uphill weighted walking.

Comparison between 6-week foam rolling intervention program with and without vibration on rolling and non-rolling sides

PURPOSE

The chronic effects of unilateral foam rolling (FR) or FR with vibration (VFR) intervention on the rolling and non-rolling sides (cross-education effects) are still unclear. Thus, this study aimed to investigate the effects of unilateral 6-week FR or VFR intervention on ankle dorsiflexion range of motion (DF ROM), muscle stiffness, and muscle strength in both rolling and non-rolling sides.

METHODS

Thirty healthy young men were randomly allocated into the FR (n = 15) or the VFR intervention group (n = 15). Participants performed three sets of unilateral FR or VFR interventions for 60 s of the calf muscles twice/week, for 6 weeks. DF ROM, gastrocnemius muscle stiffness, and maximal voluntary isometric contraction (MVIC) torque were assessed in the rolling and non-rolling sides before and after the intervention.

RESULTS

The DF ROM increased significantly (p < 0.05) to the same extent in the FR and VFR intervention groups on both rolling (FR: d = 0.58, VFR: d = 0.63) and non-rolling (FR: d = 0.39, VFR: d = 0.50) sides. Similarly, the passive torque at DF ROM increased significantly (p < 0.05) to the same extent in the FR and VFR intervention groups on both rolling (FR: d = 0.85, VFR: d = 0.77) and non-rolling (FR: d = 0.76, VFR: d = 0.68) sides. However, there were no significant changes in muscle stiffness and MVIC after FR and VFR interventions on both the rolling and non-rolling sides. FR and VFR interventions could increase the ROM in both the rolling and non-rolling sides but could not change muscle stiffness and strength.

CONCLUSIONS

The results showed that it is not necessarily needed to perform VFR to increase ROM in the long term.

Acute Effects of Static Stretching Combined with Vibration and Nonvibration Foam Rolling on the Cardiovascular Responses and Functional Fitness of Older Women with Prehypertension

Simple Summary

Thirty-seven percent of the US adult population have prehypertension, and a quarter to half of these over 65 years of age progress to hypertension in four years. Along with healthy diet, exercise or physical activity is one of the critical lifestyle factors for this population. General exercise recommendation or prescription to individuals who have cardiovascular risks is provided by organizations such as ACSM and AHA, but more detailed information and research are still needed. As the first component of any exercise program, finding the proper warm-up routine is important. We aimed to examine the acute immediate effects of three different warm-up protocols on cardiovascular responses and functional fitness testing in older women with prehypertension. Thirteen qualified subjects went through three protocols (static stretching with and without foam rolling, and stretching with vibration rolling) in three different sessions. Blood pressure was not altered only in the static stretching with foam rolling condition. Interestingly, adding the vibration component to the stretching increased the upper body flexibility and stretching. We therefore suggest the combination of static stretching with foam rolling as the safe and effective protocol for older women with prehypertension.

Abstract

We compared the effects of three warm-up protocols (static stretching (SS), static stretching with vibration foam rolling (SS + VFR), and static stretching with nonvibration foam rolling (SS + FR) on the blood pressure and functional fitness performance in older women with prehypertension. Thirteen older women went through different protocols in separate visits, and their systolic (SBP) and diastolic (DBP) blood pressure, heart rate, mean arterial pressure, brachial pulse pressure (BPP), functional fitness test (back scratch (BS), chair-sit-and-reach, 30 s arm curl (AC), 30 s chair stand, 2 min step, 8-foot up and go), and single-leg standing balance (SLB) were recorded. The SBP and BPP were significantly higher after SS and SS + VFR than after SS + FR. Both SS + FR and SS + VFR significantly improved the 2 min step, when compared with SS. Additionally, SS + VFR significantly improved the BS and AC performance. However, compared with SS and SS + FR, SS + VFR significantly reduced the SLB performance. Therefore, SS + FR may be a better warm-up protocol for older women in maintaining blood pressure. On the other hand, even though SS + VFR induced superior shoulder flexibility, aerobic endurance, and arm strength, it could impair balance.

Comparison of A Single Vibration Foam Rolling and Static Stretching Exercise on the Muscle Function and Mechanical Properties of the Hamstring Muscles

Knee extension and hip flexion range of motion (ROM) and functional performance of the hamstrings are of great importance in many sports. The aim of this study was to investigate if static stretching (SS) or vibration foam rolling (VFR) induce greater changes in ROM, functional performance, and stiffness of the hamstring muscles. Twenty-five male volunteers were tested on two appointments and were randomly assigned either to a 2 min bout of SS or VFR. ROM, counter movement jump (CMJ) height, maximum voluntary isometric contraction (MVIC) peak torque, passive resistive torque (PRT), and shear modulus of semitendinosus (ST), semimembranosus (SM), and biceps femoris (BFlh), were assessed before and after the intervention. In both groups ROM increased (SS = 7.7%, P < 0.01; VFR = 8.8%, P < 0.01). The MVIC values decreased after SS (-5.1%, P < 0.01) only. Shear modulus of the ST changed for -6.7% in both groups (VFR: P < 0.01; SS: P < 0.01). Shear modulus decreased in SM after VFR (-6.5%; P = 0.03) and no changes were observed in the BFlh in any group (VFR = -1%; SS = -2.9%). PRT and CMJ values did not change following any interventions. Our findings suggest that VFR might be a favorable warm-up routine if the goal is to acutely increase ROM without compromising functional performance.

Foam Rolling Training Effects on Range of Motion: A Systematic Review and Meta-Analysis

Background

A single foam-rolling exercise can acutely increase the range of motion (ROM) of a joint. However, to date the adaptational effects of foam-rolling training over several weeks on joint ROM are not well understood.

Objective

The purpose of this meta-analysis was to investigate the effects of foam-rolling training interventions on joint ROM in healthy participants.

Methods

Results were assessed from 11 studies (either controlled trials [CT] or randomized controlled trials [RCTs]) and 46 effect sizes by applying a random-effect meta-analysis. Moreover, by applying a mixed-effect model, we performed subgroup analyses, which included comparisons of the intervention duration (≤ 4 weeks vs > 4 weeks), comparisons between muscles tested (e.g., hamstrings vs quadriceps vs triceps surae), and study designs (RCT vs CT).

Results

Our main analysis of 290 participants with a mean age of 23.9 (± 6.3 years) indicated a moderate effect of foam-rolling training on ROM increases in the experimental compared to the control group (ES = 0.823; Z = 3.237; 95% CI 0.325–1.322; p = 0.001; I² = 72.76). Subgroup analyses revealed no significant differences between study designs (p = 0.36). However, a significant difference was observed in the intervention duration in favor of interventions > 4 weeks compared to ≤ 4 weeks for ROM increases (p = 0.049). Moreover, a further subgroup analysis showed significant differences between the muscles tested (p = 0.047) in the eligible studies. Foam rolling increased joint ROM when applied to hamstrings and quadriceps, while no improvement in ankle dorsiflexion was observed when foam rolling was applied to triceps surae.

Conclusion

Longer duration interventions (> 4 weeks) are needed to induce ROM gains while there is evidence that responses are muscle or joint specific. Future research should examine possible mechanisms underpinning ROM increases following different foam-rolling protocols, to allow for informed recommendations in healthy and clinical populations.

Effect of repeated eccentric exercise on muscle damage markers and motor unit control strategies in arm and hand muscle

To examine the contralateral repeated bout effect (CL-RBE) on muscle damage markers and motor unit (MU) control strategies, seventeen healthy adults performed two bouts of 60 eccentric contractions with elbow flexor (EF group; n ​= ​9) or index finger abductor (IA group; n ​= ​8) muscles, separated by 1 week. All participants randomly performed eccentric exercise on either the right or left arm or hand muscles, and muscle damage markers and submaximal trapezoid contraction tests were conducted pre, post, 1- and 2-day post eccentric protocol. One week after the first bout, the same exercise protocol and measurements were performed on the contralateral muscles. Surface electromyographic (EMG) signals were collected from biceps brachii (BB) or first dorsal interosseous (FDI) during maximal and submaximal tests. The linear regression analyses were used to examine MU recruitment threshold versus mean firing rate and recruitment threshold versus derecruitment threshold relationships. EMG amplitude from BB (bout 1 vs. bout 2 ​= ​65.71% ​± ​22.92% vs. 43.05% ​± ​18.97%, p ​= ​0.015, d ​= ​1.077) and the y-intercept (group merged) from the MU recruitment threshold versus derecruitment threshold relationship (bout 1 vs. bout 2 ​= ​−7.10 ​± ​14.20 vs. 0.73 ​± ​16.24, p ​= ​0.029, d ​= ​0.513) at 50% MVIC were significantly different between two bouts. However, other muscle damage markers did not show any CL-RBE in both muscle groups. Therefore, despite changes in muscle excitation and MU firing behavior, our results do not support the existence of CL-RBE on BB and FDI muscles.

Acute Effects of Vibration Foam Rolling with Light and Moderate Pressure on Blood Pressure and Senior Fitness Test in Older Women

Vibration foam rolling (VR) can improve flexibility and sports performance. However, blood pressure (BP), heart rate (HR) and senior fitness test (SFT) responses induced by an acute VR session in older women are currently unknown. Fifteen healthy women (72.90 ± 4.32 years) completed three separated randomly sequenced experimental visits. During each visit, they started with a warm-up protocol (general warm up (GW): walking + static stretching (SS), SS + VR with light pressure (VRL), or SS + VR with moderate pressure (VRM)), and completed BP, HR, SFT measurements. The systolic BP increased significantly after all three warm up protocols (p < 0.05). Both VRL and VRM protocols induced statistically significant improvements (effect size range: 0.3-1.04, p < 0.05) in the senior fitness test (back scratch, 30 s chair stand, 30 s arm curl, and 8 foot up and go), as compared to the GW. In addition, the VRM showed greater improvement for the 2 min step test when comparing with the VRL. Therefore, including VR in a warm-up protocol can result in superior SFT performance enhancement than the GW does in healthy older women.

Altered Triceps Surae Muscle-Tendon Unit Properties after 6 Months of Static Stretching

INTRODUCTION

This study examined the effects of 24 wk of daily static stretching of the plantarflexors (unilateral 4 × 60-s stretching, whereas the contralateral leg served as a control; n = 26) on joint range of motion (ROM), muscle-tendon unit morphological and mechanical properties, neural activation, and contractile function.

METHODS

Torque-angle/velocity was obtained in passive and active conditions using isokinetic dynamometry, whereas muscle-tendon morphology and mechanical properties were examined using ultrasonography.

RESULTS

After the intervention, ROM increased (stretching, +11° ± 7°; control, 4° ± 8°), and passive torque (stretching, -10 ± 11 N·m; control, -7 ± 10 N·m) and normalized EMG amplitude (stretching, -3% ± 6%; control, -3% ± 4%) at a standardized dorsiflexion angle decreased. Increases were seen in passive tendon elongation at a standardized force (stretching, +1.3 ± 1.6 mm; control, +1.4 ± 2.1 mm) and in maximal passive muscle and tendon elongation. Angle of peak torque shifted toward dorsiflexion. No changes were seen in tendon stiffness, resting tendon length, or gastrocnemius medialis fascicle length. Conformable changes in ROM, passive dorsiflexion variables, tendon elongation, and angle of peak torque were observed in the nonstretched leg.

CONCLUSIONS

The present findings indicate that habitual stretching increases ROM and decreases passive torque, altering muscle-tendon behavior with the potential to modify contractile function.

Local and Non-local Effects of Foam Rolling on Passive Soft Tissue Properties and Spinal Excitability

In sports and clinical settings, roller massage (RM) interventions are used to acutely increase range of motion (ROM); however, the underlying mechanisms are unclear. Apart from changes in soft tissue properties (i.e., reduced passive stiffness), neurophysiological alterations such as decreased spinal excitability have been described. However, to date, no study has investigated both jointly. The purpose of this trial was to examine RM’s effects on neurophysiological markers and passive tissue properties of the plantar flexors in the treated (ROLL) and non-treated (NO-ROLL) leg. Fifteen healthy individuals (23 ± 3 years, eight females) performed three unilateral 60-s bouts of calf RM. This procedure was repeated four times on separate days to allow independent assessments of the following outcomes without reciprocal interactions: dorsiflexion ROM, passive torque during passive dorsiflexion, shear elastic modulus of the medial gastrocnemius muscle, and spinal excitability. Following RM, dorsiflexion ROM increased in both ROLL (+19.7%) and NO-ROLL (+13.9%). Similarly, also passive torque at dorsiflexion ROM increased in ROLL (+15.0%) and NO-ROLL (+15.2%). However, there were no significant changes in shear elastic modulus and spinal excitability (p > 0.05). Moreover, significant correlations were observed between the changes in DF ROM and passive torque at DF ROM in both ROLL and NO-ROLL. Changes in ROM after RM appear to be the result of sensory changes (e.g., passive torque at DF ROM), affecting both rolled and non-rolled body regions. Thus, therapists and exercise professionals may consider applying remote treatments if local loading is contraindicated.

Effect of Arm Eccentric Exercise on Muscle Damage of the Knee Flexors After High-Intensity Eccentric Exercise

Repeated bout effect (RBE) describes a phenomenon that an initial unaccustomed eccentric exercise (ECC) bout can confer a protective effect against muscle damage from the subsequent same exercise. This protection has been observed in the same muscle, as well as the contralateral homologous (CL-RBE) muscle. But it is unknown whether the RBE is evident for non-local unrelated heterogonous muscles. The purpose of this study was to examine whether an initial elbow flexion (EF) muscle-damaging ECC could confer RBE against muscle damage from the subsequent ECC performed in the remote lower limb knee flexor (KF) muscle group. Twenty-seven young individuals were randomly assigned into the experimental (EXP: n = 15) and the control (CON: n = 12) groups. All participants performed a baseline unilateral KF ECC (six sets of 10 repetitions) on a randomly chosen leg. After a washout period (4 weeks), the EXP group performed 60 high-intensity unilateral EF ECC on a randomly chosen arm, followed by the same intensity exercise using the contralateral KF muscle group 2 weeks later. The CON group performed the same contralateral KF ECC, but with no prior EF ECC bout. Changes in the KF muscle damage indirect markers (muscle soreness, range of motion, and maximal isometric strength) after the ECC were compared between the baseline and second bouts for both groups with mixed factorial three-way (group × bout × time) ANOVA. Additionally, index of protection for each damage marker was calculated at 1 and 2 days after the ECC and compared between groups with independent t-tests. For both groups, the magnitude of the changes in the damage markers between the baseline and the second ECC bouts were not significantly different (all values of p > 0.05). As for the index of protection, relative to the CON, the EXP showed an exacerbating damaging effect on the KF isometric strength following the second ECC bout, particularly at the 1-day post-exercise time point (index of protection: EXP vs. CON mean ± SD = -29.36 ± 29.21 vs. 55.28 ± 23.83%, p = 0.040). Therefore, our results do not support the existence of non-local RBE.

Non-local acute stretching effects on strength performance in healthy young adults

BACKGROUND

Static stretching (SS) can impair performance and increase range of motion of a non-exercised or non-stretched muscle, respectively. An underdeveloped research area is the effect of unilateral stretching on non-local force output.

OBJECTIVE

The objective of this review was to describe the effects of unilateral SS on contralateral, non-stretched, muscle force and identify gaps in the literature.

METHODS

A systematic literature search following preferred reporting items for systematic review and meta-analyses Protocols guidelines was performed according to prescribed inclusion and exclusion criteria. Weighted means and ranges highlighted the non-local force output response to unilateral stretching. The physiotherapy evidence database scale was used to assess study risk of bias and methodological quality.

RESULTS

Unilateral stretching protocols from six studies involved 6.3 ± 2 repetitions of 36.3 ± 7.4 s with 19.3 ± 5.7 s recovery between stretches. The mean stretch-induced force deficits exhibited small magnitude effect sizes for both the stretched (-6.7 ± 7.1%, d = -0.35: 0.01 to -1.8) and contralateral, non-stretched, muscles (-4.0 ± 4.9%, d = , 0.22: 0.08 to 1.1). Control measures exhibited trivial deficits.

CONCLUSION

The limited literature examining non-local effects of prolonged SS revealed that both the stretched and contralateral, non-stretched, limbs of young adults demonstrate small magnitude force deficits. However, the frequency of studies with these effects were similar with three measures demonstrating deficits, and four measures showing trivial changes. These results highlight the possible global (non-local) effects of prolonged SS. Further research should investigate effects of lower intensity stretching, upper versus lower body stretching, different age groups, incorporate full warm-ups, and identify predominant mechanisms among others.

Non-local Acute Passive Stretching Effects on Range of Motion in Healthy Adults: A Systematic Review with Meta-analysis

BACKGROUND

Stretching a muscle not only increases the extensibility or range of motion (ROM) of the stretched muscle or joint but there is growing evidence of increased ROM of contralateral and other non-local muscles and joints.

OBJECTIVE

The objective of this meta-analysis was to quantify crossover or non-local changes in passive ROM following an acute bout of unilateral stretching and to examine potential dose-response relations.

METHODS

Eleven studies involving 14 independent measures met the inclusion criteria. The meta-analysis included moderating variables such as sex, trained state, stretching intensity and duration.

RESULTS

The analysis revealed that unilateral passive static stretching induced moderate magnitude (standard mean difference within studies: SMD: 0.86) increases in passive ROM with non-local, non-stretched joints. Moderating variables such as sex, trained state, stretching intensity, and duration did not moderate the results. Although stretching duration did not present statistically significant differences, greater than 240-s of stretching (SMD: 1.24) exhibited large magnitude increases in non-local ROM compared to moderate magnitude improvements with shorter (< 120-s: SMD: 0.72) durations of stretching.

CONCLUSION

Passive static stretching of one muscle group can induce moderate magnitude, global increases in ROM. Stretching durations greater than 240 s may have larger effects compared with shorter stretching durations.

The Effects of a Preconditioning Rolling Session on Subsequent Eccentric Exercise-Induced Muscle Damage

West, JT, Miller, WM, Jeon, S, and Ye, X. The effects of a preconditioning rolling session on subsequent eccentric exercise-induced muscle damage. J Strength Cond Res 34(8): 2112-2119, 2020-The aim of this study was to examine the effects of a preexercise unilateral quadriceps muscle rolling intervention on subsequent ipsilateral (IPSI) or contralateral (CTRA) knee extension eccentric exercise-induced muscle damage. Twenty-seven healthy volunteers (14 men) underwent an eccentric exercise protocol (6 sets of 10 repetitions with 75% of the maximal isometric strength) with a single-leg knee extension machine. Before the eccentric exercise, the subjects were randomly assigned to either (a) IPSI group: rolling the ipsilateral knee extensor muscles, (b) CTRA: rolling the contralateral muscles, or (c) Control: sitting for 6 minutes (same duration as the rolling intervention protocol) relaxed. The muscle soreness, passive knee extension range of motion, and knee extension isometric strength were measured before, immediately, 24 hours, and 48 hours after exercise. The magnitudes of the range of motion decrement were attenuated in both the IPSI (p = 0.031) and CTRA (p = 0.014) groups 24 hours after the eccentric exercise, when compared with the control. Isometric strength (p = 0.783) and muscle soreness (p = 0.586) responses were not significantly different among the 3 groups (time points and sexes merged). Additionally, women displayed an overall faster recovery than men in isometric strength (p = 0.001) and muscle soreness (p = 0.024), evidenced by the measurements at 48 hours after exercise. Our study suggests that unilateral quadriceps rolling intervention before high-intensity muscle-damaging exercise has a beneficial effect on maintaining range of motion in both the ipsilateral and contralateral muscles.

Selective Effects of Manual Massage and Foam Rolling on Perceived Recovery and Performance: Current Knowledge and Future Directions Toward Robotic Massages

Manual massage and foam rolling are commonly used by athletes for warm-up and recovery, as well as by healthy individuals for well-being. Manual massage is an ancient practice requiring the intervention of an experienced physiotherapist, while foam rolling is a more recent self-administered technique. These two topics have been largely studied in isolation from each other. In the present review, we first provide a deep quantitative literature analysis to gather the beneficial effects of each technique through an integrative account, as well as their psychometric and neurophysiological evaluations. We then conceptually consider the motor control strategies induced by each type of massage. During manual massage, the person remains passive, lying on the massage table, and receives unanticipated manual pressure by the physiotherapist, hence resulting in a retroactive mode of action control with an ongoing central integration of proprioceptive feedback. In contrast, while performing foam rolling, the person directly exerts pressures through voluntary actions to manipulate the massaging tool, therefore through a predominant proactive mode of action control, where operations of forward and inverse modeling do not require sensory feedback. While these opposite modes of action do not seem to offer any compromise, we then discuss whether technological advances and collaborative robots might reconcile proactive and retroactive modes of action control during a massage, and offer new massage perspectives through a stochastic sensorimotor user experience. This transition faculty, from one mode of control to the other, might definitely represent an innovative conceptual approach in terms of human-machine interactions.

Effects of Self-Massage Using a Foam Roller on Ankle Range of Motion and Gastrocnemius Fascicle Length and Muscle Hardness: A Pilot Study

Context: Several studies have reported that self-massage using a foam roller (FR) increased joint range of motion (ROM) immediately. However, the mechanism of increasing ROM by the FR intervention has not been elucidated. Objective: To clarify the mechanism by investigating properties and morphological changes of muscles targeted by the FR intervention. Design: An interventional study. Setting: An athletic training laboratory. Participants: Ten male college volunteers with no injuries in their lower limbs (mean [SD]: age 23.8 [3.2] y, height 173.2 [4.9] cm, weight 69.5 [8.6] kg). Intervention: The FR intervention on the right plantar flexors for 3 minutes. Main Outcome Measures: Maximum ankle ROM, muscle hardness, and fascicle length of the gastrocnemius muscle at the neutral (0°), maximum dorsiflexion, and maximum plantar flexion positions. All measurements were conducted before (PRE) and after (POST) the FR intervention. Results: Dorsiflexion ROM increased significantly at POST (PRE: 13.6° [8.0°], POST: 16.6° [8.4°]; P < .001), although plantar flexion ROM did not change significantly between PRE and POST (PRE: 40.0° [6.1°], POST: 41.1° [4.9°]). There was no significant difference in muscle hardness and fascicle length between PRE and POST in any of the angles. Conclusions: Dorsiflexion ROM increased significantly by the FR intervention in the present study; however, muscle hardness and fascicle length did not change. FR may affect not only the muscle but also the fascia, tendon, and muscle-tendon unit. The FR protocol of the present study can be applied in clinical situations, because it was found to be effective to increase ROM.

INFLUENCE OF AN ACUTE BOUT OF SELF-MYOFASCIAL RELEASE ON KNEE EXTENSION FORCE OUTPUT AND ELECTRO-MECHANICAL ACTIVATION OF THE QUADRICEPS

Background

In contrast to static stretching (SS), previous research has demonstrated increases in flexibility after an acute bout of self-myofascial release (SMR) without any subsequent decreases in force output. Previous research has utilized measures of surface electromyography (sEMG) and mechanomyography (MMG) to examine the influence of SS on the electrical and mechanical processes of muscle activation, respectively. However, there is a lack of research examining the potential changes in electro-mechanical muscle activation post-SMR.

Purpose

To examine the influence of SMR, via an acute bout of foam rolling (FR) to the vastus lateralis (VL), on the expression of knee extension force output and the inter-muscular electro-mechanical activation of the quadriceps musculature.

Study Design

Randomized crossover trial.

Methods

Twenty (10 males, 10 females) recreationally-active participants with prior FR experience completed both SMR and control (CON) testing protocols during separate testing sessions that were conducted in a randomized order 48 hours apart. During the SMR protocol, participants performed 3 sets of 60 seconds of FR over the VL portion of their quadriceps musculature, with 60 seconds of rest between sets. During the CON protocol, participants quietly sat upright for 10 minutes. Peak knee extension force output -(Force_peak) data, as well as sEMG and MMG data from the VL and the rectus femoris (RF) were collected during maximal voluntary isometric contractions (MVICs) before and after both testing protocols. Root mean square sEMG and MMG amplitudes were calculated to represent electro-mechanical muscle activation of the VL (VL-sEMG_RMS, VL-MMG_RMS) and RF (RF-sEMG_RMS, RF-MMG_RMS) musculature.

Results

Repeated measures analyses of variance (RM ANOVAs) identified a significant (p < 0.05) increase in Force_peak within the SMR protocol among males, but no change among females. No statistically significant changes in any electro-mechanical muscle activation measures were identified pre-to-post-SMR within either sex.

Conclusion

In contrast to the SS literature body, these results suggest that SMR does not influence the electro-mechanical aspects of muscle activation during MVICs. These results provide support for the absence of decreases in force output post-SMR, but further examination regarding the potential muscle mass influence of SMR on electro-mechanical muscle function remains warranted.

Level of Evidence

2c.

The effect of foam rollers of varying densities on range of motion recovery

OBJECTIVE

This study aimed to compare the effect of different density foam rollers on range of motion recovery.

METHOD

Ten active men completed two, 3-day trials in random order. During the experimental trials, all participants performed 2 min of foam rolling (FR) using a medium-density (medium trial) or hard-density (hard trial) foam roller on the right posterior thigh after completing the 90-min Loughborough Intermittent Shuttle Test (LIST). The hip joint range of motion (ROM), muscle hardness, and muscle soreness were assessed before and after the LIST and at 0 min, 20 min, 60 min, 24 h, and 48 h after FR intervention. Serum creatine kinase (CK) concentrations were assessed before the LIST and at 60 min, 24 h, and 48 h after FR intervention. The contralateral leg in each trial was used as a control.

RESULTS

The ROM at 0 min, 20 min, 60 min, 24 h, and 48 h after FR intervention were higher in the right leg (the massage leg) than in the left leg (the contralateral leg) (p < 0.05). In the right leg, the ROM at 0 min after FR intervention was higher than after the LIST (p < 0.05). There were no significant differences between the medium and hard trials for ROM. Muscle hardness, muscle soreness, and serum CK concentration were not affected by FR.

CONCLUSION

FR has a positive effect on ROM recovery. Moreover, the two roller densities provided similar ROM recovery.

The Effect of Foam Rolling Versus IASTM on Knee Range of Motion, Fascial Displacement, and Patient Satisfaction

CONTEXT

Soft tissue restrictions have been linked to poor flexibility and decreased range of motion (ROM). To decrease the soft tissue restrictions and ultimately increase ROM/flexibility, myofascial release techniques, such as foam rolling (FR) and instrument-assisted soft tissue mobilization (IASTM), have been used. However, the benefit regarding which technique is more beneficial remains unknown.

OBJECTIVE

To examine the effects of myofascial release techniques (FR vs the instrumented portion of IASTM) on knee joint ROM, rectus femoris (RF) and biceps femoris (BF) fascial displacement, and patient satisfaction.

DESIGN

Randomized controlled clinical trial.

SETTING

Mid-Atlantic University.

PARTICIPANTS

Twenty moderately active participants (age 21.1 [2.0] y) with variable levels of soft tissue restriction in the quadriceps and hamstrings started and completed the study. Participants were randomly assigned to 2 groups, FR or IASTM.

INTERVENTIONS

All participants completed the same warm-up prior to the intervention. The FR group followed the proper FR protocol for gluteals/iliotibial band, quadriceps, and hamstrings/adductors, and the participants were monitored while the protocol was completed. The IASTM group received treatment on the gluteals/iliotibial band followed by the quadriceps, adductors, and hamstrings. Participants in both groups attended intervention sessions twice per week for 3 weeks. Prior to the start, knee ROM measurements were taken, along with fascial displacement measured via ultrasound. Upon completion of the study, posttest measurements were completed. A patient satisfaction survey was also administered at this time.

MAIN OUTCOME MEASURES

Pretest to posttest knee ROM measurements, RF and BF fascial displacement, and patient satisfaction.

RESULTS

Both groups improved pretest to posttest for knee-extension ROM, with a slight trend toward increased knee-extension ROM for the FR group. Both groups improved pretest to posttest for BF and RF fascial displacement, in favor of the IASTM group for BF fascial displacement. Both groups were equally satisfied.

CONCLUSIONS

As both groups improved pretest to posttest, either treatment could be used.

Ultrasound-Guided Percutaneous Neuromodulation in Patients with Unilateral Anterior Knee Pain: A Randomized Clinical Trial

The objective of this study was to evaluate the short-term and crossover effects of a percutaneous neuromodulation (PNM) intervention on the femoral nerve, regarding the pain, knee flexion motion (range of motion (ROM)), and functionality, in patients with unilateral anterior knee pain (AKP). Our study used a randomized clinical trial design. Thirty patients were divided into two groups: one asymptomatic knee group in which patients received stimulation in the femoral nerve corresponding to the nonsymptomatic knee; and one symptomatic knee group, in which patients received stimulation in the femoral nerve corresponding to the painful knee. Pain, knee flexion ROM, Victorian Institute of Sport Assessment-Patella (VISA-P) and Kujala questionnaires were evaluated. Twenty-eight patients completed the study. Compared to their baseline values, both groups showed an increase immediately at 24 h, and at 1 week for the knee flexion ROM variable. In addition, the symptomatic knee group showed an increase for the Kujala score and a decrease for the numeric rating scale (NRS) variable from baseline to 1 week. VISA-P score did not show statistically significant differences for the time-group interaction. After the intervention, there were no differences between the groups in any measured time. Conclusion: a single-shot ultrasound-guided PNM intervention per week in the femoral nerve may be an effective treatment for improving the pain, knee flexion ROM, and knee functionality. In addition, this technique produces crossover benefits in the nonintervention limb.

Unilateral hamstring foam rolling does not impair strength but the rate of force development of the contralateral muscle

BACKGROUND

Self-administered foam rolling (SAFR) is an effective massage technique often used in sport and rehabilitation settings to improve range of motion (ROM) without impairing the strength performance. However, the effects of unilateral SAFR on contralateral non-intervened muscle's rate of force development (RFD) are unknown. Therefore, the purpose of this investigation was to examine the acute effects of unilateral hamstrings SAFR on the contralateral limb flexibility, the isometric strength, and the RFD parameters.

METHODS

Thirty-four subjects (21 women) completed two separate randomly sequenced experimental visits, during which the control (rested for 10 min) or ten, 30-second SAFR were performed with the dominant hamstring muscle group. Before (Pre) and after (Post) the interventions, the contralateral hip flexion passive ROM, the maximal explosive isometric strength of the contralateral knee flexors with the corresponding prime mover muscles' surface electromyographic (EMG) amplitude were measured. Separate two-way (time ×intervention) repeated measures analyses of variance (ANOVAs) were used to examine the potential changes of the dependent variables.

RESULTS

The SAFR significantly improved the contralateral limb ROM (Pre vs. Post: 68.3 ± 21.0 vs. 73.2 ± 23.2 degrees, p < 0.001; d = 0.22). No change was found for the contralateral isometric strength or the maximal EMG amplitude. For the RFD parameters, the percent changes of the RFDs for the first 50, 100, and 200 ms of the maximal explosive isometric contraction were -31.2%, -16.8%, and -10.1%, respectively, following the unilateral SAFR, relative to the control condition. In addition, the decrement of the first 50-ms RFD reached statistical significance (p = 0.007; Cohen's d = 0.44).

CONCLUSION

Ten sets of 30-second unilateral hamstring SAFR improved the ROM of the non-intervened contralateral limb, but decreased its ability to generate force, especially during the early phase (e.g., 50 ms) of the maximal explosive contraction.

A Meta-Analysis of the Effects of Foam Rolling on Performance and Recovery

Foam rolling is thought to improve muscular performance and flexibility as well as to alleviate muscle fatigue and soreness. For this reason, foam rolling has become a popular intervention in all kinds of sport settings used to increase the efficiency of training or competition preparation as well as to speed post-exercise recovery. The objective of this meta-analysis was to compare the effects of foam rolling applied before (pre-rolling as a warm-up activity) and after (post-rolling as a recovery strategy) exercise on sprint, jump, and strength performance as well as on flexibility and muscle pain outcomes and to identify whether self-massage with a foam roller or a roller massager is more effective. A comprehensive and structured literature search was performed using the PubMed, Google Scholar, PEDro, and Cochrane Library search engines. Twenty-one studies were located that met the inclusion criteria. Fourteen studies used pre-rolling, while seven studies used post-rolling. Pre-rolling resulted in a small improvement in sprint performance (+0.7%, g = 0.28) and flexibility (+4.0%, g = 0.34), whereas the effect on jump (-1.9%, g = 0.09) and strength performance (+1.8%, g = 0.12) was negligible. Post-rolling slightly attenuated exercise-induced decreases in sprint (+3.1%, g = 0.34) and strength performance (+3.9 %, g = 0.21). It also reduced muscle pain perception (+6.0%, g = 0.47), whereas its effect on jump performance (-0.2%, g = 0.06) was trivial. Of the twenty-one studies, fourteen used foam rollers, while the other seven used roller massage bars/sticks. A tendency was found for foam rollers to offer larger effects on the recovery of strength performance (+5.6%, g = 0.27 vs. -0.1%, g = -0.01) than roller massagers. The differences in the effects between foam rolling devices in terms of pre-rolling did not seem to be of practical relevance (overall performance: +2.7 %, g = 0.11 vs. +0.4%, g = 0.21; flexibility: +5.0%, g = 0.32 vs. +1.6%, g = 0.39). Overall, it was determined that the effects of foam rolling on performance and recovery are rather minor and partly negligible, but can be relevant in some cases (e.g., to increase sprint performance and flexibility or to reduce muscle pain sensation). Evidence seems to justify the widespread use of foam rolling as a warm-up activity rather than a recovery tool.