The Effectiveness of PNF Versus Static Stretching on Increasing Hip-Flexion Range of Motion

The Effects of TMR® Fab 6 on Hamstring Flexibility in Healthy Subjects; An Exploratory Observational Investigation

Background

Stretching programs are designed to improve hamstring flexibility by attempting to mechanically increase the length of the target tissue. However, other manual treatment approaches such as those utilized in Total Motion Release (TMR®), could be beneficial by identifying body asymmetries to assess and treat soft tissue impairments leading to diminished extensibility.

Purpose

The purpose of this study was to determine the effectiveness of the TMR® Fab 6 assessment and treatment to increase hamstring flexibility in healthy participants following one session of TMR®.

Study Design

Observational Cohort study.

Methods

A convenience sample of 20 healthy participants (10 males, 10 females) were recruited from three institutions. Following collection of demographic information and a brief medical history, each participant performed a five minute warm-up on the stationary bike at a moderate intensity (80-90 RPMs) followed immediately by the bilateral performance of the Active Knee Extension Test (AKET) and Passive Straight Leg Raise (PSLR) to assess hamstring muscle length. Participants were randomly placed in the TMR® or control group. The TMR® group completed the "Fab 6" evaluation and treatment, while the control group performed one repetition of standing active hip flexion every 30-seconds for 15-minutes with both knees in full extension. Upon completion of treatment, control and TMR® groups were immediately re-evaluated on the AKET and the PSLR in the same order and fashion as baseline testing. Participants were asked to return in 24-hours for the same objective measurements as previously described.

Results

A significant time by group interaction was identified across all variables (p ≤ 0.001) for AKET and PSLR except the PSLR preferred leg from post-treatment to 24hr follow-up. The most significant increase in the AKET occurred in the TMR® group between baseline and post-treatment of the non-preferred leg (12.15°±2.94) when compared to the control group (7.15°±1.56).

Conclusion

The results of the study suggest that implementing a regionally interdependent treatment approach like TMR® results in significant improvements in hamstring extensibility and hip ROM compared to the control group.

Level of evidence

3.

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.

The knowledge of movement experts about stretching effects: Does the science reach practice?

OBJECTIVE

Stretching is performed with numerous purposes in multiple settings such as prevention, rehabilitation, fitness training and sports. Its patterns of use substantially depend on the education and beliefs of health care and exercise professionals as they represent the multiplicators recommending and prescribing interventions to clients, patients and athletes. This study investigated movement experts' knowledge about the scientific evidence on stretching effects.

DESIGN

Survey study.

PARTICIPANTS

A total of 117 exercise and health professionals (physiotherapists, sports scientists, coaches) attending a training convention in Austria (male: n = 44, female: n = 73, 36±11 years) completed a digital survey. With its 22 items, the questionnaire addressed the movement experts' awareness of the evidence on stretching effects regarding a variety of related topics selected based on the findings of topical systematic reviews.

RESULTS

The majority of the individuals (57-88%) assumed positive effects of stretching on recovery, prevention of muscle injury, range of motion, muscular imbalance and artery elasticity. No or adverse effects were mostly claimed on bone injury prevention, maximal/explosive strength, and delayed-onset muscle soreness. In only 10 of 22 items, participants' classifications were in accord with the scientific evidence.

CONCLUSIONS

The awareness of research findings on stretching effects among exercise and health professionals is alarmingly low. Future studies may hence be geared to improve implementation and science communication.

Effect of PNF stretching performed in the AKE position on hip, knee, and ankle flexibility

BACKGROUND

To measure hamstring flexibility, the active knee extension (AKE) test is preferred over the straight leg raise (SLR) test as it can be used to measure hamstring flexibility more selectively. However, hamstring stretching is primarily conducted in the SLR position (maximal hip flexion in the supine position) as it allows for maximal hip flexion in the supine position.

OBJECTIVE

This study evaluates the effects of proprioceptive neuromuscular facilitation (PNF) stretching in the AKE position (maximal knee extension with 90∘ flexion of the hip in the supine position) on hip, knee, and ankle flexibility.

METHODS

SLR, AKE, and active dorsiflexion (ADF) tests were used to determine the range of motion (ROM) before (pre-ROM) and after (post-ROM) stretching. PNF stretching consisted of maximal isometric knee flexion at the end range with external resistance to prevent knee flexion. One set of PNF stretches (five trials of six seconds each) was conducted.

RESULTS

The post-ROMs of hip, knee, and ankle measured via the SLR, AKE, and ADF tests, respectively, were significantly higher than the pre-ROMs.

CONCLUSIONS

The improvement in knee flexibility was greater than the improvement in hip and ankle flexibility. The AKE position is recommended in clinical settings during PNF stretching for individuals with hamstring tightness. Furthermore, PNF stretching in the AKE position increases the ADF ROM.

Efficacy of proprioceptive neuromuscular facilitation on functioning in patients with bilateral hip osteoarthritis: A pilot randomized controlled trial

BACKGROUND

Hip osteoarthritis (OA) is a chronic progressive disease that impresses a noticeable burden to society and healthcare systems. Physical exercise constitutes the first-line hip OA treatment approach, nevertheless, there is currently no gold standard method to treat this disease.

OBJECTIVE

To evaluate the efficacy of proprioceptive neuromuscular facilitation (PNF) on functioning in patients with hip OA.

METHOD

A pilot randomized controlled trial (RCT) was carried out on patients with painful bilateral hip OA with a body mass index (BMI) < 30 kg/m2. After the randomization, the experimental group was treated with PNF protocol and the control group with conventional physical therapy (10 sessions of manual therapy, 5 sessions/week for 2 weeks). The Harris Hip Score (HHS) was the primary outcome, whereas we assessed as secondary outcomes: pain, range of motion, and muscle strength of hip, physical performance, and quality of life.

RESULTS

Twenty patients (40 hips) were enrolled and randomized into two groups: PNF group (mean age: 70.7 ± 8.07; BMI: 25.1 ± 3.07; 7 females and 3 males) and control group (mean age: 74.9 ± 10.72; BMI: 26.8 ± 3.78; 6 females and 4 males). The results showed a statistically significant improvement of HHS in the study group (T1: 90.6 ± 5.63) than in the control group (T1: 77.3 ± 10.9) (between-group p value < 0.001). Three months after the treatment we have statistically significant maintenance in the PNF group (T2:89.6±6.32, within-group ΔT0-T2 p< 0.01) while the control group did not maintain the improvements recorded at T1 (T2: 71.4 ± 15.8).

CONCLUSION

The results of this pilot RCT showed that incorporating PNF exercises into the rehabilitation program yielded notable enhancements in improving lower limb function, strength and ROM in hip OA patients. Nonetheless, further prospective studies including wider sample size are needed to implement scientific knowledge on this physical therapy approach, in patients with hip osteoarthritis.

Clinical value of ankle flexion and extension exercises combined with a psychological intervention in knee osteoarthritis

BACKGROUND

Considering the limited effectiveness of clinical interventions for knee osteoarthritis (KOA), it is necessary to continue to explore appropriate and effective treatment strategies to improve the condition of KOA patients.

AIM

To clarify the influence of ankle flexion and extension exercises combined with a psychological intervention on the psychological status and activities of daily living (ADLs) of patients with KOA.

METHODS

The research participants were 116 KOA patients admitted to The First Affiliated Hospital of Guizhou University of Traditional Chinese Medicine between May 2019 and May 2022, including 54 patients receiving routine treatment, care and psychological intervention (control group) and 62 patients additionally treated with ankle flexion and extension exercises (research group). The two groups were comparatively analyzed in terms of psychological status (Self-rating Anxiety/Depression Scale, SDS/SAS), ADLs, knee joint function (Lysholm Knee Scoring Scale), pain (Visual Analog Scale, VAS), fatigue (Multidimensional Fatigue Inventory, MFI), and quality of life (QoL; Short-Form 36 Item Health Survey, SF-36).

RESULTS

After evaluation, it was found that the postinterventional SDS, SAS, VAS, and MFI scores in the research group were significantly reduced compared with the baseline (before the intervention) values and those of the control group, while the postinterventional Lysholm, ADL and SF-36 scores were markedly elevated.

CONCLUSION

Therefore, ankle flexion and extension exercises are highly effective in easing negative psychological status, enhancing ADLs, daily living ability, knee joint function and QoL, and relieving pain and fatigue in KOA patients, thus warranting clinical promotion.

Eight weeks of proprioceptive neuromuscular facilitation stretching and static stretching do not affect muscle-tendon properties, muscle strength, and joint function in children with spastic cerebral palsy

BACKGROUND

While the effect of static stretching for individuals with cerebral palsy is questionable, recent results suggest that the combination with activation seems promising to improve muscle-tendon properties and function. Therefore, this study analyzed the effects of 8-week proprioceptive neuromuscular facilitation stretching on the gastrocnemius medialis muscle-tendon properties, muscle strength, and the ankle joint in children with spastic cerebral palsy in comparison to static stretching.

METHODS

Initially, 24 children with spastic cerebral palsy were randomly assigned to a static stretching (10.7 ± 1.8 years) or proprioceptive neuromuscular facilitation stretching group (10.9 ± 2.6 years). Plantar flexors were manually stretched at home for 300 s and ∼ 250-270 s per day four times a week for eight weeks, respectively. Assessments of ankle joint function (e.g., range of motion), muscle-tendon properties, and isometric muscle strength were conducted using 3D motion capture, 2D ultrasound, dynamometry, and electromyography. A mixed analysis of variance was used for the statistical analysis.

FINDINGS

Stretching adherence was high in the proprioceptive neuromuscular facilitation stretching (93.1%) and static stretching group (94.4%). No significant changes (p > 0.05) were observed in ankle joint function, muscle-tendon properties, and isometric muscle strength after both interventions. Moreover, no differences (p > 0.05) were found between the stretching techniques.

INTERPRETATION

The findings support the idea that manual stretching (neither proprioceptive neuromuscular facilitation stretching nor static stretching) performed in isolation for eight weeks may not be appropriate to evoke significant changes in muscle-tendon properties, voluntary muscle strength, or joint function in children with spastic cerebral palsy.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04570358.

Immediate and Long-Term Effectiveness of Proprioceptive Neuromuscular Facilitation and Static Stretching on Joint Range of Motion, Flexibility, and Electromyographic Activity of Knee Muscles in Older Adults

Introduction and Objective: Previously, various stretching techniques were compared to study their effects on the different physiological parameters of hamstring muscles in the elderly population. There is no research that compares the immediate and long-term effects of proprioceptive neuromuscular facilitation-contract–relax (PNF-CR) and static stretching (SS) techniques on knee range of motion (ROM), hamstring flexibility, and knee flexor muscle EMG activity in the elderly. This study intends to compare the same. Methods: A total of 30 males aged 55–75 years were randomly assigned into the PNF-CR group (n = 10), SS group (n = 10), and control group (n = 10). The PNF-CR group received four trials of the contract–relax technique, the SS group received passive stretching of an 80 s duration by the therapist, and the control group received no intervention. A total of 12 sessions were given during the four-week period. Knee range of motion, electromyographic activity of the biceps femoris, and the sit-and-reach test were taken for the dominant side thrice: pre-intervention, immediately after stretching, and after the training period. Results: A statistically significant difference was observed in the maximum voluntary isometric contraction (MVIC) of biceps femoris between the PNF and the control groups (p = 0.01) after four weeks of intervention. The knee ROM and hamstring flexibility for the PNF group showed significant improvement immediately post-test (p = 0.01) and after four weeks of training (p = 0.07 and p = 0.001). SS showed significant results for both ROM and flexibility after four weeks of intervention (p = 0.001), and significant immediate post-test improvements were seen for ROM only (p = 0.007). Conclusions: PNF stretching has an immediate, as well as long-term, effect on knee ROM and hamstring flexibility, whereas it has only a long-term effect on muscle electromyographic activity. SS has an immediate, as well as long-term, effect on knee ROM and only a long-term effect on hamstring flexibility, without any immediate or long-term effects on muscle electromyographic activity.

Acute and Chronic Effects of Supervised Flexibility Training in Older Adults: A Comparison of Two Different Conditioning Programs

Flexibility training is a fundamental biological process that improves the quality of life of the elderly by improving the ranges of motion of joints, postural balance and locomotion, and thus reducing the risk of falling. Two different training programs were assessed acutely and after 12 weeks by means of the sit-and-reach test. Thirty-one healthy older adults were randomly divided into three groups: the Experiment I group (Exp) performed strength and static stretching exercises; the Experiment II group performed dynamic and static stretching exercises; and participants assigned to the control group maintained a sedentary lifestyle for the entire period of the study. Flexibility acutely increased in Exp I by the first (ΔT0 = 7.63 ± 1.26%; ES = 0.36; p = 0.002) and second testing sessions (ΔT1 = 3.74 ± 0.91%; ES = 0.20; p = 0.002). Similarly, it increased in Exp II significantly by the first (ΔT0 = 14.21 ± 3.42%; ES = 0.20; p = 0.011) and second testing sessions (ΔT1 = 9.63 ± 4.29%; ES = 0.13; p = 0.005). Flexibility significantly increased over the 12 weeks of training in Exp I (ΔT0 - T1 = 9.03 ± 3.14%; ES = 0.41; p = 0.020) and Exp II (ΔT0 - T1 = 22.96 ± 9.87%; ES = 0.35; p = 0.005). The acute and chronic differences between the two groups were not significant (p > 0.05). These results suggest the effectiveness of different exercise typologies in improving the flexibility of the posterior muscular chains in older adults. Therefore, the selection of a program to optimize training interventions could be based on the physical characteristics of the participants.

Does static stretching change uniformly the quadriceps elasticity in physically actives subjects?

PURPOSE

Verify the acute responses of static stretching (SS) on the rectus femoris (RF), vastus medialis (VM), and vastus lateralis (VL) elasticity and knee/hip range of motion (ROM). Additionally, to investigate if there are consistency among quadriceps muscle elasticity after SS.

METHODS

Acute effect of SS on pre-post-intervention design. Thirtheen healthy participants (both genders) proposed for a pre-post experimental design. RF, VM, and VL elasticity (strain ratio, SR) was evaluated bilaterally by ultrasound with quasi-static elastography. Higher SR values refer to more rigid tissues. A SS protocol of 3 series of 30 s was applied at right lower limb. The left lower limb was considered as control group. Also, photogrammetry evaluated the knee/hip ROM.

RESULTS

For SR muscle comparisons, VM was lower (less stiff) than VL and RF at pre- and post-SS. For time comparisons, no differences were observed for SR and ROM at pre- and post-SS. However, the effect size of the quadriceps SR at SS lower limb was higher than control.

CONCLUSION

Acute effects of SS did not change the quadriceps SR or knee/hip ROM in healthy and active subjects. Non-uniform quadriceps SR are observed (VM < VL and RF) independently of SS. Future studies should consider different protocols, muscles, and populations.

Short-Term Effects of Three Types of Hamstring Stretching on Length, Neurodynamic Response, and Perceived Sense of Effort-A Randomised Cross-Over Trial

Background: Stretching techniques for hamstring muscles have been described both to increase muscle length and to evaluate nerve mechanosensitivity. Aim: We sought to evaluate the short-term effects of three types of hamstring stretching on hamstring length and report the type of response (neural or muscular) produced by ankle dorsiflexion and perceived sense of effort in asymptomatic subjects. Methods: A randomised cross-over clinical trial was conducted. A total of 35 subjects were recruited (15 women, 20 men; mean age 24.60 ± 6.49 years). Straight leg raises (SLR), passive knee extensions (PKE), and maximal hip flexion (MHF) were performed on dominant and non-dominant limbs. In addition, the intensity of the applied force, the type and location of the response to structural differentiation, and the perceived sensation of effort were assessed. Results: All stretching techniques increased hamstring length with no differences between limbs in the time*stretch interaction (p < 0.05). The perceived sensation of effort was similar between all types of stretching except MHF between limbs (p = 0.047). The type of response was mostly musculoskeletal for MHF and the area of more neural response was the posterior knee with SLR stretch. Conclusions: All stretching techniques increased hamstring length. The highest percentage of neural responses was observed in the SLR stretching, which produced a greater increase in overall flexibility.

Efficacy of Single Stretching Session of Iliopsoas Using Proprioceptive Neuromuscular Facilitation Versus Muscle Energy Technique on Low Back Pain in Patients With Lumbar Hyper-Lordosis

Background and objectives

One of the most frequent conditions for which people seek physiotherapy treatment is low back pain (LBP). When the aetiology of low back pain is whittled down to mechanical factors, pelvic tilting becomes apparent. The iliopsoas muscle is the key to relieving LBP in such circumstances, and since it is tightened, we concentrated on stretching it adequately in this study. Proprioceptive neuromuscular facilitation (PNF) and muscle energy technique (MET) are two stretching techniques that we have compared for this purpose. There are many other stretching techniques available, but the evidence has proven these two to be the most effective.

Methods

The participants in the study were those between the ages of 18 and 60 who had exaggerated lumbar lordosis, or LBP, and met the inclusion criteria. There were two groups created: A and B. PNF and traditional physiotherapy was used to manage the participants in group A, and MET and traditional physiotherapy were used to manage the participants in group B. Each group underwent the same pre-and post-tests, which included the Numerical Pain Rating Scale (NPRS) to assess pain intensity; a universal goniometer to measure hip joint extension range of motion (ROM) to assess iliopsoas flexibility; and a side-lying X-ray to measure the lumbosacral angle (LSA) to determine the angle of lumbar lordosis.

Result

In both the stretching interventions, i.e., PNF and MET, there were statistically significant differences in pain, hip extension range of motion, and lumbar lordosis angle (P > 0.0001). However, for the PNF group, the difference between the pre-and post-test was greater than that for the MET group.

Conclusion

The current study, which included 100 participants, demonstrated that both PNF and MET are remarkably effective for loosening the tight iliopsoas. A comparison of both techniques showed that the PNF group had benefited significantly more than the MET group.

Gender difference in effects of proprioceptive neuromuscular facilitation stretching on flexibility and stiffness of hamstring muscle

Objective: This study investigated the acute effects of PNF stretching on hamstring flexibility and muscle stiffness of lower limbs between genders.

Methods: 15 male and 15 female university students without any injury histories on lower limbs in the past 3 months were included in this study were selected. All subjects were measured by MyotonPRO before and after stretching to determine the muscle stiffness of the biceps femoris muscle (BF), semitendinosus muscle (ST) of the hamstring and the medial gastrocnemius muscles (MG), lateral gastrocnemius muscles (LG), and the soleus (SOL) of the triceps surae muscles. Additionally, their flexibility was measured using the sit-and-reach test (the SR test) and passive hip range of motion (ROM). Differences based on time (pre-stretching vs. post-stretching) and sex (females vs. males) were assessed using 2 × 2 repeated measures AVONA.

Results: There was a significant decrease in the stiffness of the hamstring and triceps surae muscles after stretching (BF, MG, LG, and SOL: p < 0.001; ST: p = 0.003). The muscle stiffness of the hamstring and triceps surae muscles is larger in males than in females at all time points (p < 0.001). There was a significant increase in hip flexion angle and the SR test in males and females after PNF stretching (p < 0.001); However, there was no difference in the change in the muscle stiffness and the flexibility between genders (p > 0.05).

Conclusion: PNF stretching helped improve hamstring flexibility and decrease muscle stiffness. Stretching the hamstrings can also contribute to a decrease in the stiffness of the triceps surae muscles. The muscle stiffness of males before and after stretching is always greater than that of females. However, there was no difference in the change of improvement in stretching between genders.

The Immediate Effect of Adding Lumbar Mobilization to A Static Stretching Program on Hamstrings Range of Motion: An Exploratory Study

A contributing risk factor and a byproduct of a hamstrings strain is limited hamstrings range of motion (ROM). Some evidence supports static stretching (SS) and lumbar spinal mobilization therapy (LSMT) as an effective means for increasing hamstrings ROM. However, the efficacy of combining LSMT and SS for increasing hamstrings ROM is unknown. The objective of the study is to quantify the immediate effects of the combination of LSMT and SS compared to LSMT and SS on hamstrings ROM in a healthy population. Thirty participants were randomized by block allocation into one of three intervention groups: (1) LSMT (unilateral lumbar PA mobilization at L-4); (2) SS; or (3) combination of LSMT and SS. Hamstrings ROM was measured pre- and post-intervention by the active knee extension test (AKET). There was no group-by-time interaction effect (p = 0.871). Within group analysis revealed a significant statistical change and a large effect size: LSMT (p = .037, RCI = 3.36, d = 0.771); SS (p = 0.035, RCI = 2.94, d = 0.781); combination (p = .005, RCI = 4.21, d = 1.186. The findings suggest that the combination of LSMT and SS does not have a further effect on hamstrings ROM compared to the individual results of LSMT or SS.

Predicting Hamstring Strains in Soccer Players Based on ROM: An Analysis From a Gender Perspective

Purpose: The aim of this study was to explore if specific hip and knee range-of-movement (ROM) tests can predict a risk factor for hamstring strain (HS) injury in male and female soccer players. Methods: One hundred amateur soccer players (56 men and 44 women) performed six tests to determine hip and knee ROM: straight leg raise test (SLR), modified Thomas test (TT), hip internal and external rotation (ER), hip abduction and adduction, Nachlas test and Ridge test. A logistic regression analysis was carried out to create a predictive model for HS injuries. Results: The percentage of HS injury was 20.45% and 30.35%, for female and male players. The logistic regression showed a significant model for both genders on the logit of suffering an HS injury with active-SLR and TT variables for females (R²_CS = 0.491; R²_N = 0.771) and active SLR and ER variables for males (R²_CS = 0.623; R²_N = 0.882). The predictive models correctly classify 95.5% and 94.6% of cases presenting good sensitivity (77.8% and 88.2%) and full (100%) and high (97.4%) specificity respectively. Furthermore, female players showed a greater ROM than males (p ≤ 0.01). Conclusion: Both female and male soccer players that suffered a HS injury had lower ROM in SLR, NT and RT and higher ROM in the TT that non-injured players. The tests that most likely predict HS injury are SLR and TT in females and SLR and ER in males. Thus, it is suggested to including specific exercises in amateur soccer players training programs to improve hip and knee ROM for injury prevention.

Conservative treatment of iliotibial band syndrome in runners: Are we targeting the right goals?

OBJECTIVE

Iliotibial band syndrome (ITBS) is presumably caused by excessive tension in the iliotibial band (ITB) leading to compression and inflammation of tissues lying beneath it. Usually managed conservatively, there is a lack of scientific evidence supporting the treatment recommendations, and high symptom recurrence rates cast doubt on their causal effectiveness. This review discusses the influence of common physiotherapeutic measures on risk factors contributing to tissue compression beneath the ITB.

METHODS

The potential pathogenic factors are presented on the basis of a simple biomechanical model showing the forces acting on the lateral aspect of the knee. Existent literature on the most commonly prescribed physiotherapeutic interventions is critically discussed against the background of this model. Practical recommendations for the optimization of physiotherapy are derived.

RESULTS

According to biomechanical considerations, ITBS may be promoted by anatomical predisposition, joint malalignments, aberrant activation of inserting muscles as well as excessive ITB stiffness. Hip abductor strengthening may correct excessive hip adduction but also increase ITB strain. Intermittent stretching interventions are unlikely to change the ITB's length or mechanical properties. Running retraining is a promising yet understudied intervention.

CONCLUSIONS

High-quality research directly testing different physiotherapeutic treatment approaches in randomized controlled trials is needed.

Effects of a Single Proprioceptive Neuromuscular Facilitation Stretching Exercise With and Without Post-stretching Activation on the Muscle Function and Mechanical Properties of the Plantar Flexor Muscles

A single proprioceptive neuromuscular facilitation (PNF) stretching exercise can increase the range of motion (ROM) of a joint but can lead to a decrease in performance immediately after the stretching exercise. Post-stretching activation (PSA) exercises are known as a possible way to counteract such a drop in performance following a single stretching exercise. However, to date, no study has investigated the combination of PNF stretching with PSA. Thus, the aim of this study was to compare the effects of a PNF stretching exercise with and without PSA on the muscle function (e.g., ROM) and mechanical properties of the plantar flexor muscles. Eighteen physically active males volunteered in the study, which had a crossover design and a random order. The passive shear modulus of the gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) was measured in a neutral position with shear wave elastography, both pre- and post-intervention. Maximum voluntary isometric contraction (MVIC) peak torque, maximum voluntary dynamic contraction peak torque, dorsiflexion ROM, and passive resistive torque (PRT) were also measured with a dynamometer. The interventions were 4×30s of PNF stretching (5s of contraction) and two sets of three exercises with 20 or 40 fast ground contacts (PNF stretching+PSA) and PNF stretching only. ROM was found to have increased in both groups (+4%). In addition, the PNF stretching+PSA group showed a decrease in PRT at a given angle (-7%) and a decrease in GM and mean shear modulus (GM+GL; -6%). Moreover, the MVIC peak torque decreased (-4%) only in the PNF stretching group (without PSA). Therefore, we conclude that, if PNF stretching is used as a warm-up exercise, target-muscle-specific PSA should follow to keep the performance output at the same level while maintaining the benefit of a greater ROM.

Influence of submaximal isometric contractions of the hamstrings on electromyography activity and force while functioning as hip extensors

BACKGROUND: Although the medial and lateral hamstrings are clearly distinct anatomically and have different functions in the transverse plane, they are often considered as one muscle during rehabilitation. OBJECTIVE: The purpose of the study was to compare the electromyographic (EMG) activity between the prone position and the supine position during maximal isometric contraction and to additionally confirm the effect of submaximal isometric contractions on EMG activity of medial and lateral hamstrings, and force. METHODS: In the prone position, EMG activities of the long head of biceps femoris (BFLH) and semitendinosus (ST) were measured during the maximal isometric contraction. In the supine position, hip extension force with EMG activity were measured during the maximal and the submaximal isometric contractions. RESULTS: EMG activity in the prone position was significantly decreased in the supine position. In the supine position, there was a significant difference between the BFLH and ST during the maximal isometric contraction, but not during the submaximal isometric contractions. CONCLUSIONS: The dependence on the hamstrings could be relatively lower during hip extensions. When the medial and lateral hamstrings are considered separately, the lateral hamstrings may show a more active response, with increased muscle length, in clinical practice.

A Survey on Stretching Practices in Women and Men from Various Sports or Physical Activity Programs

Recommendations for prescribing stretching exercises are regularly updated. It appears that coaches progressively follow the published guidelines, but the real stretching practices of athletes are unknown. The present study aimed to investigate stretching practices in individuals from various sports or physical activity programs. A survey was completed online to determine some general aspects of stretching practices. The survey consisted of 32 multiple-choice or open-ended questions to illustrate the general practices of stretching, experiences and reasons for stretching. In total, 3546 questionnaires were analyzed (47.3% women and 52.7% men). Respondents practiced at the national/international level (25.2%), regional level (29.8%), or recreationally (44.9%). Most respondents (89.3%) used stretching for recovery (74.9%) or gains of flexibility (57.2%). Stretching was generally performed after training (72.4%). The respondents also indicated they performed stretching as a pre-exercise routine (for warm-up: 49.9%). Static stretching was primarily used (88.2%) but when applied for warm-up reasons, respondents mostly indicated performing dynamic stretching (86.2%). Only 37.1% of the respondents indicated being supervised. Finally, some gender and practice level differences were noticed. The present survey revealed that the stretching practices were only partly in agreement with recent evidence-based recommendations. The present survey also pointed out the need to improve the supervision of stretching exercises.

Strength Training versus Stretching for Improving Range of Motion: A Systematic Review and Meta-Analysis

(1) Background: Stretching is known to improve range of motion (ROM), and evidence has suggested that strength training (ST) is effective too. However, it is unclear whether its efficacy is comparable to stretching. The goal was to systematically review and meta-analyze randomized controlled trials (RCTs) assessing the effects of ST and stretching on ROM (INPLASY 10.37766/inplasy2020.9.0098). (2) Methods: Cochrane Library, EBSCO, PubMed, Scielo, Scopus, and Web of Science were consulted in October 2020 and updated in March 2021, followed by search within reference lists and expert suggestions (no constraints on language or year). Eligibility criteria: (P) Humans of any condition; (I) ST interventions; (C) stretching (O) ROM; (S) supervised RCTs. (3) Results: Eleven articles (n = 452 participants) were included. Pooled data showed no differences between ST and stretching on ROM (ES = -0.22; 95% CI = -0.55 to 0.12; p = 0.206). Sub-group analyses based on risk of bias, active vs. passive ROM, and movement-per-joint analyses showed no between-protocol differences in ROM gains. (4) Conclusions: ST and stretching were not different in their effects on ROM, but the studies were highly heterogeneous in terms of design, protocols and populations, and so further research is warranted. However, the qualitative effects of all the studies were quite homogeneous.

Effects of proprioceptive neuromuscular facilitation stretching at low-intensities with standing toe touch on developing and maintaining hamstring flexibility

BACKGROUND

Proprioceptive neuromuscular facilitation (PNF) stretching at low intensities has been rarely investigated. Previous studies have shown that hamstring flexibility after stretching is only temporary.

OBJECTIVE

The aim of this study was to assess the effect of low intensities (40% and 10% of maximum voluntary isometric contraction, MVIC) of PNF stretching on hamstring muscles and to assess the effect of standing toe touch on the duration of hamstring flexibility.

METHODS

This was a single-blind randomized controlled trial. Sixty-four healthy adults (age, 22.67 ± 1.73 years) were selected and divided into four groups: 40% intensity PNF stretching (P40), 10% intensity PNF stretching (P10), 40% intensity PNF stretching with toe touch (P40 with TT), and 10% intensity PNF stretching with toe touch (P10 with TT). Hamstring flexibility was measured using the active knee extension test (pre-stretching, post-stretching, and 3, 6, 9, 12, and 15 min after PNF stretching).

RESULTS

In the P40, P40 with TT, and P10 with TT groups, significant changes were observed at all time points after stretching (p < 0.05). In the P10 group, significant changes were only observed immediately post stretching (p = 0.006) and at 3 min (p = 0.029) after stretching. In terms of maintaining the duration of flexibility, the P40 with TT and P10 with TT groups were superior to the P40 and P10 groups.

CONCLUSION

PNF stretching at low intensity, approaching 40% of MVIC, led to more flexibility than 10% MVIC. Additionally, standing toe touch after PNF stretching is recommended to develop and maintain hamstring flexibility.