The test-induced warm-up effect on hamstring flexibility tests

Background

Although the effect of active warm-up (WU) on acute flexibility enhancement is well documented, the test-induced WU effect in muscle length test has not been widely studied.

Objective

This study aimed to verify the test-induced WU effect on hamstring flexibility tests.

Methods

The active knee extension (AKE) was performed using the right leg, whereas the straight leg raise (SLR) was performed using the left leg. Ten trials of AKE or SLR were performed: two as the pre-intervention trials (Pre); six as the WU intervention; and another two trials as the post-intervention (Post). During WU, subjects in the WO-Hold group performed six trials of the AKE or SLR without hold, and those in the W-Hold group performed six trials of the AKE or SLR with a 5 s hold.

Results

A significant difference was noted between Pre-AKE and Post-AKE, and between Pre-SLR and Post-SLR, respectively, in both the groups. The effect of WU is clear when performing consecutive AKE or SLR without any additional hold.

Conclusion

Practitioners should be cautious in interpreting the testing result to avoid overestimation of the treatment effect since the test itself may induce substantial WU effect to the target tissues.

Comparison of muscle tightness between knees in individuals with unilateral osteoarthritis and its relationship with pain and function

BACKGROUND

Unilateral osteoarthritis (OA) affects single knees and presents a unique scenario where individuals experience varying degrees of symptoms between their affected and unaffected knees.

OBJECTIVE

This study aims to investigate differences in muscle tightness between symptomatic and asymptomatic knees in individuals with unilateral knee OA while exploring the interplay among pain, functionality, and muscle tightness.

METHODS

In this cross-sectional study, thirty knee OA patients underwent assessments for hamstring (Active Knee Extension, Straight Leg Raise), iliotibial band (Ober Test), and quadriceps tightness (Modified Thomas Test). Pain intensity was measured using the Visual Analog Scale (VAS), and functional limitations were evaluated via the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

A negative correlation was observed between participants' pain and AKE (p= 0.004, r=-0.515), ASLR (p= 0.27, r=-0.403), Ober (p= 0.010, r=-0.461) values. However, no significant correlation was found with the Modified Thomas value (p= 0.204, r=-0.239). There was also a negative correlation between participants' WOMAC scores and AKE (p= 0.019, r=-0.427), OBER (p= 0.004, r=-0.510), and Modified Thomas (p= 0.022, r=-0.416) values, while ASLR (p= 0.286, r=-0.202) values showed no significant correlation. Comparisons between AKE, Ober, and Modified Thomas values showed higher values in asymptomatic extremities (AKE: p= 0.025, Ober: p= 0.021, Modified Thomas: p= 0.030).

CONCLUSION

This study emphasizes the significance of muscle tightness in the symptomatic extremities of individuals with unilateral knee OA. The results indicate that increased muscle tightness makes pain worse and limits movement. It's crucial for healthcare providers treating OA to focus on improving muscle flexibility, reducing pain, and enhancing overall function.

The relationship between lower extremity muscle tightness and pain and disability in individuals with non-specific chronic low back pain

BACKGROUND

Low back pain is a common health issue, and such pains are often associated with muscle tightness. Understanding the link between lower back pain and tight lower extremity muscles is essential for effective pain management and enhanced quality of life.

OBJECTIVE

The objective of this study was to investigate the relationship between lower extremity muscle tightness and pain and disability in individuals with non-specific low back pain (NSLBP).

METHODS

A total of 52 individuals with NSLBP were enrolled in this cross-sectional study. Lower extremity muscle tightness was assessed using various clinical tests, including the Active Knee Extension Test, Active Straight Leg Raise, Ober Test, and Modified Thomas Test. Pain intensity and disability were evaluated using the Visual Analog Scale and the Oswestry Disability Index, respectively. Statistical analyses were conducted to assess the correlation between muscle tightness, pain, and disability.

RESULTS

The study found weak to moderate negative correlations between lower extremity muscle tightness and both pain intensity and disability in individuals with NSLBP (r: -0.287 to -0.526, p <  0.05). Dominant and non-dominant extremities exhibited differences in muscle flexibility, with the dominant extremity showing greater flexibility (p <  0.05).

CONCLUSIONS

In individuals with NSLBP, lower extremity muscle tightness is closely related to pain severity and disability. These findings suggest that lower extremity muscle tightness plays a significant role in the severity of low back pain and disabilities. Additionally, the observed flexibility difference between dominant and non-dominant extremities warrants further investigation for more personalized treatment approaches.

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.

Combined effect of myofascial release and passive stretching on plantar pressure in individual with hamstring tightness- an experimental study

INTRODUCTION

The lower kinetic chain is known to be affected by hamstring tightness which causes biomechanical alterations. As per the literature, short hamstring might cause prolonged forefoot loading, which can cause higher repeated stress on the plantar fascia. There is evidence supporting the use of various stretching and myofascial release techniques for hamstring tightness, further research is needed to investigate their impact on plantar pressure. Hence the study aims to determine combined effect of myofascial release and passive stretching on plantar pressure in individual with hamstring tightness.

METHODS

This was an experimental pre-post study design with 67 randomised screenings from asymptomatic health care science students aged 18 to 25. From this scientific survey, a sample size of 47 students having HMS tightness based on the popliteal angle were recruited using a universal goniometer. An intervention was proposed that included MFR and passive stretching in 3 sessions on alternate days. Plantar pressure of these individuals was noted by using the "Harris and Beath foot printing mat" before and after the intervention.

RESULT

Significant pressure changes were observed after intervention: great toe of right side (p = 0.001), toes 2 to 5 of right side (p = 0.010) and left side (p = 0.008), first metatarsal of left side (p = 0.010), lateral forefoot of right side (p = 0.019) and left (p = 0.018), medial heel (p = 0.044), and lateral heel of right side (p = 0.025). These values substantiate the enhancement in plantar pressure.

CONCLUSION

The combined effect of Myofascial release and passive stretching in an individual with hamstring tightness resulted in a significant increase in popliteal angle and plantar pressure.

The immediate effects of foam rolling of the hamstrings muscle group on the contractile properties of the knee muscles in football players

INTRODUCTION

Excessive amounts of intense training, without adequate recovery time, can overload the musculoskeletal, immune, and metabolic systems, resulting in a potentially negative effects on later exercise performance. During the competitive period, the ability to recover after intense training and competition is an important factor of success in soccer. The purpose of this study was to determine the effect of hamstring foam rolling on the knee muscle contractile properties in soccer players, after a sports-specific load.

METHODS

20 male professional soccer players were included and contractile properties of the biceps femoris, rectus femoris, vastus medialis and vastus lateralis muscles were measured with tensiomyography, before and after a Yo-Yo interval test and after 5 × 45 s of hamstring foam rolling. Additionally, active and passive knee extensibility before and after the intervention were measured. A mixed linear model was performed to determine the differences between the mean values of the groups. The experimental group performed foam rolling, while the control was resting.

RESULTS

Five repetitions of 45 s of hamstring foam rolling had no statistically significant effect (p > 0.05) on any of the measured muscles following the Yo-Yo interval test or foam rolling intervention. There were no statistically significant differences in delay time, contraction time and maximum muscle amplitude between groups. Active and passive knee extensibility did not differ between groups.

DISCUSSION AND CONCLUSION

It seems that foam rolling does not affect mechanical properties of the knee muscles or hamstring extensibility in soccer players, after a sports-specific load.

Examination of the correlation between the knee extension angles in the sitting and supine positions measured using ImageJ software: a prospective cross-sectional study

[Purpose] We aimed to examine the correlation between the knee extension angles in the sitting and supine positions measured using ImageJ software. [Participants and Methods] A total of 50 legs in 25 healthy participants (17 males and 8 females) were included in our study. The knee extension angle was measured in the sitting and supine positions with the participants actively and maximally extending their knee joint on one side. The participants were photographed from the side with their knees centered in the image. Thereafter, the photographs were imported into the ImageJ image processing software to calculate the knee extension angles. [Results] The mean values of the knee extension angles in the sitting and supine positions were 131.5 ± 11.2° and 132.1 ± 12.2°, respectively, with a correlation coefficient of 0.85. No systematic errors were observed, and the minimal detectable change was 12.9°. [Conclusion] The knee extension angle in the sitting position showed a strong correlation with that in the supine position, with no systematic errors observed. Therefore, measurement of the knee extension angle in the sitting position can be an alternative to its measurement in the supine position.

Comparison of utilizing modified hold-relax, muscle energy technique, and instrument-assisted soft tissue mobilization on hamstring muscle length in healthy athletes: Randomized controlled trial

INTRODUCTION

The hamstring muscle shortness is the primary risk factor for sports-related injuries. Numerous treatments are available for lengthening of hamstring muscle. The main purpose of this study was to compare the immediate effect of modified hold-relax, muscle energy technique (MET), and instrument assisted soft tissue mobilization-Graston techniques (IASTM-GT) on length of hamstring muscle in young healthy athletes.

METHODS

60 athletes comprising of 29 females and 31 males were recruited in the present study. Participants were allocated to 3 groups of IASTM-GT (N = 20, 13 male, 7 female), Modified Hold-relax (N = 20, 8 male, 12 female), and MET (N = 20, 7 male, 13 female). Active knee extension and passive straight leg raising (SLR), and toe touch test were performed before and immediately after the intervention by a blinded assessor. For the comparison of dependent variables across time, 3*2 repeated measure ANOVA was utilized.

RESULTS

Interaction of group by time was significant for passive SLR (P < 0.001). Interaction of group by time was not significant for active knee extension (P = 0.17). The results showed that dependent variables increased significantly in all groups. The effect size (Cohen's d) in the groups of IASTM-GT, modified Hold-relax, and MET was 1.7, 3.17, and 3.12, respectively.

CONCLUSION

Although the measures were improved in all groups, it seems that IASTM-GT can be used as a safe and efficient treatment, which can be a suitable candidate alongside modified hold-relax and MET for increasing the hamstrings muscle length in healthy athletes.

Correlation Between Foot Posture and Hamstring Muscle Tightness

Background  The hamstring muscle is related to the lumbar spine, pelvic, and lower limb movement dysfunction, as well as low back pain and abnormal gait. The kinematic chain's distal elements dysfunctions may affect the body's proximal segments. There is a biomechanical connection between the foot and proximal segments of the body and its effect on the body's functional status, but there is a lack of research that focuses on the correlation between foot posture and hamstring muscle tightness. The study aimed to find the correlation between hamstring muscle tightness and foot posture using the foot posture index (FPI). Methods After obtaining ethical committee approval, necessary authorization was obtained from relevant authorities to proceed with participant screening. Informed consent was obtained from every participant, accompanied by a comprehensive explanation of the study. Screening of participants was conducted based on specific inclusion and exclusion criteria. These criteria were crucial for selecting a homogeneous sample and ensuring the study's objectives were met. The assessment of foot posture was carried out using FPI, and hamstring tightness was examined using an active knee extension test. Result and discussion In our study, which included 188 participants aged between 18 and 25 (mean age: 21.91±1.97), we examined the correlation between FPI and active knee extension (AKE) test results. Using Pearson's correlation coefficient, we found a statistically significant correlation between the FPI and AKE test results. For the right side, the r-value was 0.678 (p-value = 0.0001); for the left side, the r-value was 0.653 (p-value = 0.0001); and for the total, the r-value was 0.663 (p-value = 0.0001). These findings indicate a significant relationship between the FPI and AKE test results. Conclusion The findings of our study revealed a significant relationship between hamstring tightness and pronation of the foot, as measured by the FPI. Understanding this relationship is crucial as it sheds light on the potential impact of hamstring tightness on foot biomechanics. By establishing this link, our study contributes to the body of knowledge surrounding the prevention of alterations in foot biomechanics. It highlights the importance of addressing hamstring tightness to mitigate potential foot pronation issues. Moreover, the study serves as a stepping stone for future research endeavors. It lays the groundwork for further large-scale investigations that encompass a broader range of age groups.

Dynamic soft tissue mobilization versus proprioceptive neuromuscular facilitation in reducing hamstring muscle tightness in patients with knee osteoarthritis: a randomized control trial

BACKGROUND

Knee osteoarthritis (KOA) considered as one of the most common degenerative diseases of synovial joint. KOA is mostly managed by physical therapy, focused on pain management, the range of motion and muscle strengthening but muscle flexibility is usually neglected. A study was conducted to evaluate the effectiveness of dynamic soft tissue mobilization (DSTM) in comparison with the proprioceptive neuromuscular facilitation (PNF) stretching in the management of hamstring tightness, reduction of pain intensity and improvement of physical functionality in KOA.

METHODS

Forty eight patients with KOA were randomly allocated to group A receiving DTSM and group B receiving PNF stretching. The cryotherapy and isometric strengthening exercises were also given to both groups. Total treatment duration consisted of 4 weeks, 3 sessions per week and total 12 sessions per patient. Each treatment session comprised of 30 min. At baseline and post treatment, Active knee extension test(AKET), Visual analogue scale (VAS), and Knee Injury and Osteoarthritis Outcome Score (KOOS) were used to assess hamstring flexibility, pain intensity level and physical functional capability respectively. The continuous variables were shown as mean and standard deviations. For the comparison of outcome within and between groups, paired sample and independent t-test was applied. Considerable p value was less than 0.05.

RESULTS

The between group analysis of VAS, right AKE test, and left AKE test showed non-significant (p > 0.05) mean difference as 0.2 (95% CI= -0.29, 0.70), 1.79 (95% CI= -1.84, 4.59), 1.78 (95% CI= -1.6, 5.19) respectively. KOOS domains of symptom, pain, ADLs, sports and recreational, and quality of life had also non-significant (p > 0.05) mean difference as 1.12 (95% CI= -4.05, 6.3), -5.12 (95% CI= -12.71, 2.46), -2.55 (95% CI= -7.47, 2.38), -2.7 (95% CI= -9.72, 4.3), and - 0.68 (95% CI= -7.69, 6.36) respectively. Significant (p < 0.001) improvement was shown in both groups for all outcome measures after 12 sessions.

CONCLUSION

DSTM and PNF stretching, both treatments are equally beneficial in KOA for hamstring flexibility, pain reduction and functional mobility in terms of AKET, VAS, and KOOS respectively.

TRIAL REGISTRATION

ClincalTrials.Gov with ID: NCT04925895, 14/06/2021, retrospectively registered.

The immediate effect of unilaterally applied lumbar mobilisations on the passive straight leg raise and ninety-ninety test in asymptomatic adults: A randomised crossover trial

OBJECTIVES

This study assessed the immediate effect of unilateral posterior-anterior lumbar mobilisations on trunk and lower limb flexibility in asymptomatic individuals.

STUDY DESIGN

Randomised cross-over trial.

PARTICIPANTS

Twenty-seven participants (age = 26.0 years ±6.4) with no current or recent history of lower back or leg pain/surgery completed the study.

MAIN OUTCOME MEASURES

Participants attended two sessions, receiving either grade 3 ('treatment') or grade 1 ('sham') unilateral spinal mobilisations. Outcome measures (modified-modified Schober's test [MMST], ninety-ninety test [NNT], and passive straight-leg raise [PSLR]) were assessed immediately before and after (post-1 and post-2) the intervention. An instrumented hand-held dynamometer was used to measure the change in NNT and PSLR joint angle (deg) and passive stiffness (Nm/deg) pre- and post-intervention.

RESULTS

The mean change in PSLR angle at the first (P1) and maximal (P2) point of discomfort following the treatment was 4.8° and 5.5°, and 5.6° and 5.7°, larger than the sham at post-1 and post-2, respectively. There was no effect of the treatment on the PSLR at P1 or P2 for the contralateral limb at either timepoint. There was no effect of the treatment on MMST distance, NNT angle or passive stiffness, or PSLR passive stiffness, for either limb.

CONCLUSIONS

Immediate effects of unilateral posterior-anterior lumbar mobilisations in asymptomatic individuals are isolated to treatment side and limited to a small increase in PSLR range, with no change in lumbar motion or the NNT test.

Validity and reliability of the measurement instrument of the nursing outcome health-related Physical Fitness (2004), proposed and transculturally adapted to the Spanish context

BACKGROUND

Presently, physical inactivity is the main public health problem in many countries worldwide. Physical activity promotes the maintenance or improvement of one's physical condition. Physical fitness has been established as the main biological marker of the state of health of an individual, and therefore, there is a clear need to measure health-related physical fitness through the use of a reliable and valid instrument. This study is a continuation of the transcultural adaptation process and a new proposal of the nursing outcome Physical Fitness (2004), found in the 5^th Edition of the Nursing Outcomes Classification. The objective of this study was to examine the validity and reliability of the nursing outcome Health-Related Physical Fitness survey, proposed and transculturally adapted to the Spanish context.

METHODS

An instrumental study to validate the nursing outcome Physical Fitness (2004), from the 5^th Edition of the Nursing Outcome Classification was carried out. It took place between the months of May, 2016 to May, 2017. On the first stage, the instrument proposed Health-Related Physical Fitness survey was administered to 160 adults who used the Health Services of Murcia, Spain by three independent evaluators. After 4 weeks, it was administered again to 33 participants to calculate the intra-rater reliability. Lastly, the SF-12v2 Health Survey was administered to obtain external evidence of validity.

RESULTS

The inter-rater reliability of the nursing outcome proposed obtained high values (between 0.91-0.99) in the evaluations performed by the three evaluators. As for the intra-rater reliability, high values were obtained (0.94-1), except for the item "balance", which was moderate (0.56). Lastly, a positive and statistically significant correlation (p < 0.05) was obtained between the Physical Component Summary, and the dimensions Physical Functioning and General Health from the SF-12v2 Health Survey, and the global score of the Health-Related Physical Fitness proposed instrument.

CONCLUSIONS

The validity and reliability results of the nursing outcome Health-Related Physical Fitness survey, proposed and transculturally adapted to the Spanish context, were adequate for its use by nurses with adults who use the Health Services of Murcia. However, this instrument must be analyzed with more diverse samples of health services users.

The Influence of a Single Instrument-Assisted Manual Therapy (IAMT) for the Lower Back on the Structural and Functional Properties of the Dorsal Myofascial Chain in Female Soccer Players: A Randomised, Placebo-Controlled Trial

Background: Instrument-assisted manual therapy (IAMT) is indicated to improve flexibility, reduce pain, and induce hyperaemia locally and along myofascial chains. The underlying effects are largely unclear. This randomised, placebo-controlled pilot study aimed to gain first insights into these effects, primarily on the structural level, through ultrasonography. Methods: 67 healthy female soccer players aged 20.9 (±3.9) years were examined after right lumbar intervention (IAMT: intervention group (IG), heat application: comparison group (CG), pressure-less placebo: placebo group (PG)). Ultrasonography (absolute movement and shear motion), flexibility tests (passive straight leg raise test (PSLR), lumbar and thoracic double inclinometry), and superficial skin temperature were recorded before (t0), immediately (t1) and 45 min after the intervention (t2). Results: IAMT decreased the absolute mobility of the superficial lamina and its shear motion to the superficial fascia compared with the PG (t1; p < 0.05). PSLR improved in the IG compared with the CG (t2) and PG (t1, t2; p < 0.05). The temperature increased in the IG and CG compared with the PG (t1, t2) and in the CG compared with the IG (t1; p < 0.05). Conclusion: IAMT of the lumbar back briefly reduces absolute mobility of the superficial lamina and its shear motion to the superficial fascia, improves flexibility, and increases the temperature.

Effects of different stretch durations on the strength of the proximal and distal group of muscles - a randomized trial

BACKGROUND

Different researchers have studied the effects of different types of stretching on different muscle groups. Since distal muscles are fully activated and proximal muscles are sub-optimally activated; thus, we might see different responses to stretching in the proximal and distal groups of muscles depending on their muscle activation. Therefore, this study aimed to compare the acute effects of 2, 4, and 8 minutes of intermittent static stretching (SS) on the isometric maximum voluntary contraction force (MVCF) of proximal (Hamstring) and distal (Calf) groups of muscles.

METHODS

Two groups pretest-posttest experimental design was used. A total of thirty participants were randomly assigned into two groups, and twenty-eight completed the intervention. In both groups, participants participated in three experimental trials (SS2, SS4, and SS8) on 3 days. 2-minute intermittent stretching (SS2) was performed on day-I, 4-minute (SS4) on day II, and 8-minute (SS8) on day III. Isometric MVCF was measured at pre-intervention, 0-, 10-, and 20-minute post-intervention periods in both groups.

RESULTS

In the proximal group: SS2, SS4, and SS8 did not affect isometric MVCF at the 0-, 10-, and 20-minute post-intervention periods (P > .05). In distal group: SS2 did not affect isometric MVCF at 0- and 10-minute post-intervention periods (P > .05), however at 20-minute, MVCF increased by 11.06% (P < .05). SS4 and SS8 also did not alter isometric MVCF in the Calf at 0-, 10-, and 20-minute post-intervention periods (P > .05). No significant differences were observed between the proximal and distal groups (P > .05).

CONCLUSION

2-, 4-, and 8-minute intermittent SS did not affect the isometric strength in both muscle groups. In addition, proximal and distal groups of muscles responded similarly to three different duration intermittent SS.

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.

Physical fitness profiles of female Australian football players across five competition levels

OBJECTIVES

To examine physical fitness profiles of female Australian football players and investigate differences according to competition level.

METHODS

A testing battery of 28 physical fitness assessments was undertaken with 240 players across five competition levels: elite senior (≥18 years), non-elite senior (≥18 years), high-level junior (<18 years), non-elite junior (14-17 years), and non-elite junior (10-13 years). Physical fitness profiles were examined and competition level differences were investigated using multivariate analyses of variance.

RESULTS

Significant differences (p<0.001) were observed between competition levels in body composition (η²_p=0.225), flexibility (η²_p=0.071), muscular strength and endurance (η²_p=0.238), balance (η²_p=0.093), reaction time (η²_p=0.103), and whole-body locomotor performance (η²_p=0.200). Elite seniors and high-level juniors were stronger (p<0.001-0.043), faster (p=0.001-0.022), more responsive (p<0.001-0.048), and had better cardiorespiratory fitness (p<0.001) compared to the non-elite groups. Additionally, body composition and muscular strength and endurance differences were common between the senior and non-elite junior groups.

CONCLUSIONS

This is the first study to comprehensively profile physical characteristics of female Australian footballers across a broader development pathway. These preliminary findings may assist sport practitioners to better understand athlete development, provide insight on talent identification and development programs, and injury management in this population.

Acute Effects of Tissue Flossing Coupled with Functional Movements on Knee Range of Motion, Static Balance, in Single-Leg Hop Distance, and Landing Stabilization Performance in Female College Students

Flexibility, specifically that in the amplitude of sagittal-plane range of motion (ROM), can improve jump landing patterns and reduce the potential for sports injury. The use of floss bands (FLOSS) reportedly increases joint range of motion (ROM) in the shoulder, ankle, and elbow joints. However, little research on the effectiveness of FLOSS on the knee joint has been conducted. This study investigated the effects of FLOSS on knee ROM, static balance, single-leg-hop distance, and landing stabilization performance in women. This study had a crossover design. Twenty active female college students without musculoskeletal disorders were randomly assigned to receive a FLOSS intervention or elastic bandage (ELA) control on their dominant knees. The participants underwent FLOSS and ELA activities on two occasions with 48 h of rest between both sets of activities. The outcomes were flexibility of the quadriceps and hamstrings, how long one could maintain a single-leg stance (with and without eyes closed), distance on a single-leg triple hop, and score on the Landing Error Scoring System (LESS); these outcomes were evaluated at preintervention and postintervention (immediately following band removal and 20 min later). After the FLOSS intervention, the participants’ hamstring flexibility improved significantly (immediately after: p = 0.001; 20 min later: p = 0.002), but their quadricep flexibility did not. In addition, FLOSS use did not result in worse single-leg stance timing, single-leg triple-hop distance, or landing stabilization performance relative to ELA use. Compared with the ELA control, the FLOSS intervention yielded significantly better LESS at 20 min postintervention (p = 0.032), suggesting that tissue flossing can improve landing stability. In conclusion, the application of FLOSS to the knee improves hamstring flexibility without impeding static balance, and improves single-leg hop distance and landing stabilization performance in women for up to 20 min. Our findings elucidate the effects of tissue flossing on the knee joint and may serve as a reference for physiotherapists or athletic professionals in athletic practice settings.

Manipulative therapy of sacral torsion versus myofascial release in patients clinically diagnosed posterior pelvic pain: a consort compliant randomized controlled trial

BACKGROUND CONTEXT

Chronic low back pain represents a health care problem with substantial costs. It is generally accepted that approximately 10% to 25% of patients with persistent chronic low back pain may have pain arising from the sacroiliac joints.

PURPOSE

This study aimed to analyze the effects of manipulative therapy of sacral torsion versus myofascial release on disability, pain intensity, and mobility in patients with chronic low back pain and sacroiliac joints.

STUDY DESIGN/SETTING

A prospective, single-blinded randomized clinical trial.

PATIENT SAMPLE

Sixty-four patients (mean±SD age: 51±9; 60% female) with chronic low back pain and sacroiliac joints comprised the patient sample. No participant withdrew because of adverse effects.

OUTCOME MEASURES

Self-reported disability (primary), pain intensity, scale of kinesiophobia, quality of life, isometric endurance of trunk flexor muscles, and lumbar mobility in flexion were assessed at baseline, pos-treatment, and one month follow-up.

METHODS

Participants were randomly assigned to a sacral torsion manipulation group or myofascial release group, receiving a total of 12 sessions (once weekly).

RESULTS

ANCOVA did not showed a statistically significant difference between groups for disability (95% CI -2.40-1.90, p=.177). Effect sizes were large in both groups at both follow-up periods. Similar results were achieved for all secondary outcomes (p˂. 05). The linear model longitudinal analyses showed significant improvements in both groups over time for all outcomes with the exception of fear of movement (manipulative: Minimum within-groups change score 1.91, p˂.001; myofascial: 1.66, p˂.001).

CONCLUSION

Manipulative and myofascial release therapy in patients with clinically diagnosed sacroiliac joints syndrome resulted in a similar short-term benefits on patient reported disability. Both groups experienced similar decrease in the intensity of pain over time, although no clinically meaningful effects were demonstrated in either group.

Time-based effects of different duration stretching on hamstring muscle strength

BACKGROUND

Stretching is believed to decrease muscle strength. The aim of this paper was to examine the time course (immediate, and 10- and 20-minutes post-stretching) for the effects of 2, 4, and 8 minutes of static-stretching (SS) on the isometric maximum voluntary contraction force (MVCF) of hamstring muscles with a pretest-post-test experiment design.

METHODS

A total of 14 subjects with a mean age of 25 years participated in three experimental trials on three different days. Day I for static stretching for 2 minutes (SS<inf>2</inf>), day II for 4 minutes (SS<inf>4</inf>), and day III for 8 minutes (SS<inf>8</inf>). Testing was conducted before (pre), immediately after (post), and at 10- and 20-minutes post-stretching. MVCF was measured using the strain gauze as the main outcome measure.

RESULTS

MVCF increased with SS<inf>2</inf> at 0 minutes (1.31%), 10 minutes (3.4%), and 20 minutes (4.1%) postintervention. MVCF increased with SS<inf>4</inf> at 0 minutes (1.13%), 10 minutes (9.6%) and 20 minutes (7.1%) postintervention. MVCF decreased with SS<inf>8</inf> at 0 minutes (2.9%), but increased at 10 minutes (1.86%) and 20 minutes (0.99%) postintervention. All these changes were not statistically significant (P>0.05).

CONCLUSIONS

In hamstring stretching, 2, 4 and 8 minutes increased MVCF, but results were not statistically significant. Thus, 2 to 8 minutes long-duration stretching exercises could safely be performed before a strength-training session.

Effects of two different stretching techniques on proprioception and hamstring flexibility: a pilot study

Aim: This study aimed to compare the immediate and long-term effect of proprioceptive neuromuscular facilitation (PNF) contract-relax-antagonist-contract (CRAC) exercises versus static stretching on proprioception and flexibility in males with hamstring shortness. Patients & methods: Knee extension angle test was used to measure flexibility and isokinetic dynamometer to evaluate proprioception. Assessments were evaluated at baseline, after first exercise and eighth week. The hamstring stretching was applied 3 days a week for 8 weeks. Results: Flexibility and position sense were similar in the immediate and long term (p > 0.05). However, the motion sense increased significantly in long term within the PNF CRAC group (p = 0.02). Conclusion: Both stretching exercises are effective for improving flexibility. Moreover, PNF CRAC improved motion sense more than static stretching in the long term. Clinical trial registration number: NCT04026646.

The effects of dry needling to the thoracolumbar junction multifidi on measures of regional and remote flexibility and pain sensitivity: A randomized controlled trial

BACKGROUND

Dry needling (DN) has been consistently shown to decrease pain sensitivity and increase flexibility local to the site of treatment, however it is unclear whether these effects are limited to the region of treatment or can be observed remote to the area of treatment.

OBJECTIVE

To determine the immediate, short-term effects of DN to the thoracolumbar junction on regional and remote flexibility, and to observe if changes in pain sensitivity can occur remote to site of treatment.

DESIGN

Double-blind randomized clinical trial.

METHODS

Fifty-four subjects with low back pain and decreased length in at least one hamstring were randomized to receive either DN or sham DN to the T12 and L1 multifidi. Participants underwent regional (fingertip-to-floor) and remote flexibility (passive knee extension, passive straight leg raise) and pressure pain threshold (PPT) testing of the upper and lower extremity before, immediately after and 1 day after treatment. ANCOVAs were used to analyze flexibility data, with the covariate of pre-treatment values. Paired t-tests were used for difference in remote pain sensitivity.

RESULTS

Statistically larger improvements in regional flexibility, but not remote flexibility, were observed immediately post-treatment in those who received DN than in those receiving sham DN (p = .0495; adjusted difference 1.2, 95% CI 0.002-2.3). Differences between upper and lower extremity PPT were not significant.

CONCLUSION

DN can potentially have immediate changes in regional flexibility, but effects are not sustained at 24-h follow-up. DN may not affect remote flexibility or segmental pain sensitivity.

Neural Mobilization Short-Term Dose Effect on the Lower-Limb Flexibility and Performance in Basketball Athletes: A Randomized, Parallel, and Single-Blinded Study

CONTEXT

Neural mobilization is commonly used in sports, and previous studies have suggested that it has a positive impact on lower-limb flexibility and performance. However, studies exploring the effect of neural mobilization dosage are almost nonexistent.

OBJECTIVES

This study aimed to assess whether 2 distinct dosages of neural gliding mobilization (4 and 8 sets of 10 repetitions) impact the flexibility and performance of both the mobilized and nonmobilized lower limb in basketball athletes differently.

DESIGN

Randomized, parallel, and single-blinded study.

SETTING

Amateur and professional basketball clubs.

PARTICIPANTS

Fifty-two basketball athletes (40 men and 12 women), who were distributed into 2 groups; one received 40 (n = 28) and the other 80 repetitions (n = 24) of neural gliding mobilization.

INTERVENTION

Neural gliding mobilization applied to a single limb (the dominant limb).

MAIN OUTCOME MEASURES

Knee extension angle for hamstring flexibility; hop tests and single-leg vertical jump for performance.

RESULTS

There was a significant main effect of time (P < .001), a significant interaction between time and limb for flexibility (P = .003), and a significant interaction between time and limb for the single-leg hop test (P = .032). No other significant main effect for any of the remaining variables was found (P > .05).

CONCLUSIONS

The application of both 40 repetitions and 80 of neural gliding significantly improved lower-limb flexibility, and one was not superior to the other. Neither one dosage nor the other positively or negatively impacted the lower-limb performance of basketball athletes.

The Case for Retiring Flexibility as a Major Component of Physical Fitness

Flexibility refers to the intrinsic properties of body tissues that determine maximal joint range of motion without causing injury. For many years, flexibility has been classified by the American College of Sports Medicine as a major component of physical fitness. The notion flexibility is important for fitness has also led to the idea static stretching should be prescribed to improve flexibility. The current paper proposes flexibility be retired as a major component of physical fitness, and consequently, stretching be de-emphasized as a standard component of exercise prescriptions for most populations. First, I show flexibility has little predictive or concurrent validity with health and performance outcomes (e.g., mortality, falls, occupational performance) in apparently healthy individuals, particularly when viewed in light of the other major components of fitness (i.e., body composition, cardiovascular endurance, muscle endurance, muscle strength). Second, I explain that if flexibility requires improvement, this does not necessitate a prescription of stretching in most populations. Flexibility can be maintained or improved by exercise modalities that cause more robust health benefits than stretching (e.g., resistance training). Retirement of flexibility as a major component of physical fitness will simplify fitness batteries; save time and resources dedicated to flexibility instruction, measurement, and evaluation; and prevent erroneous conclusions about fitness status when interpreting flexibility scores. De-emphasis of stretching in exercise prescriptions will ensure stretching does not negatively impact other exercise and does not take away from time that could be allocated to training activities that have more robust health and performance benefits.

The 4-Element Movement System Model to Guide Physical Therapist Education, Practice, and Movement-Related Research

The movement system has been adopted as the key identity for the physical therapy profession, and recognition of physical therapists' primary expertise in managing movement dysfunction is an important achievement. However, existing movement system models seem inadequate for guiding education, practice, or research. Lack of a clear, broadly applicable model may hamper progress in physical therapists actually adopting this identity. We propose a model composed of 4 primary elements essential to all movement: motion, force, energy, and control. Although these elements overlap and interact, they can each be examined and tested with some degree of specificity. The proposed 4-element model incorporates specific guidance for visual, qualitative assessment of movement during functional tasks that can be used to develop hypotheses about movement dysfunction and serve as a precursor to more quantitative tests and measures. Human movement always occurs within an environmental context and is affected by personal factors, and these concepts are represented within the model. The proposed scheme is consistent with other widely used models within the profession, such as the International Classification of Functioning, Disability and Health and the Patient Management Model. We demonstrate with multiple examples how the model can be applied to a broad spectrum of patients across the lifespan with musculoskeletal, neurologic, and cardiopulmonary disorders.

Effects of flexibility and strength training on peak hamstring musculotendinous strains during sprinting

BACKGROUND

Hamstring injury is one of the most common injuries in sports involving sprinting. Hamstring flexibility and strength are often considered to be modifiable risk factors in hamstring injury. Understanding the effects of hamstring flexibility or strength training on the biomechanics of the hamstring muscles during sprinting could assist in improving prevention strategies and rehabilitation related to these injuries. The purpose of this study was to determine the effects of altering hamstring flexibility or strength on peak hamstring musculotendinous strain during sprinting.

METHODS

A total of 20 male college students (aged 18-24 years) participated and were randomly assigned to either a flexibility intervention group or a strength intervention group. Each participant executed exercise training 3 times a week for 8 weeks. Flexibility, sprinting, and isokinetic strength testing were performed before and after the 2 interventions. Paired t tests were performed to determine hamstring flexibility or strength intervention effects on optimal hamstring musculotendinous lengths and peak hamstring musculotendinous strains during sprinting.

RESULTS

Participants in the flexibility intervention group significantly increased the optimal musculotendinous lengths of the semimembranosus and biceps long head (p ≤ 0.026) and decreased peak musculotendinous strains in all 3 bi-articulate hamstring muscles (p ≤ 0.004). Participants in the strength-intervention group significantly increased the optimal musculotendinous lengths of all 3 hamstring muscles (p ≤ 0.041) and significantly decreased their peak musculotendinous strain during sprinting (p ≤ 0.017).

CONCLUSION

Increasing hamstring flexibility or strength through exercise training may assist in reducing the risk of hamstring injury during sprinting for recreational male athletes.

Normative data for hip strength, flexibility and stiffness in male soccer athletes and effect of age and limb dominance

OBJECTIVE

The objective was to establish normative data for hip strength, flexibility, and stiffness in male soccer athletes and to investigate the effect of age and limb dominance on these variables.

DESIGN

Cross-sectional.

SETTING

Soccer team physical therapy department.

PARTICIPANTS

A total of 293 asymptomatic male soccer athletes were assessed. Elite youth players aged 15-17 years and professional adult players aged 18-29 years old.

MAIN OUTCOME MEASURES

Rectus femoris, iliopsoas, hamstring muscle flexibility, passive hip stiffness, and isometric hip strength were measured using a goniometer, inclinometer, and handheld dynamometer, respectively. Descriptive and mixed analyses of variance were used as statistical procedures.

RESULTS

The dominant limb had lower iliopsoas (P = 0.010) and rectus femoris (P = 0.003) flexibility and higher external rotators torque compared to the non-dominant limb (P = 0.006) in both age groups. In adult athletes, the dominant limb had lower hip stiffness than the non-dominant limb (P = 0.002). Adults had higher hip external rotator torque than younger athletes (P < 0.0001). No differences were observed for hamstrings flexibility and hip extensors torque.

CONCLUSION

This study provided normative data of hip strength, flexibility, and stiffness for youth and adult male soccer athletes. In addition, there were no clinically relevant inter-limb differences.

The Relationship Between Low Back Pain Incidence and Ultrasound Assessment of Trunk Muscles in Adult Soccer Players: A Cohort Study

Background: Few studies have demonstrated the connection between trunk muscle thickness and low back pain (LBP) in athletes. Objectives: This study aimed to define whether the thickness of the lateral abdominal muscles (LAM) and lumbar multifidus (LM) are related to LBP incidence in elite male soccer players. Methods: In this short-term cohort study, 42 elite male soccer players from professional soccer teams were followed for a season. The muscle thickness of LAM and the cross-sectional area (CSA) of the LM were assessed. The relation between the incidence of LBP and the aforementioned factors was evaluated after the cohort study. Results: Thirty-seven participants completed the study, and seven participants (18.91%) experienced LBP during the follow-up period. No significant relationship was detected between LBP and the thickness of LAM and CSA of LM (P > 0.05). None of the other variables had any relationship with LBP incidence (P > 0.05). Conclusions: The LAM thickness and CSA of LM during a resting position and drawing-in maneuver was found not to be directly related to LBP incidence in elite male soccer players in the short term. Assessing these muscles’ conditions in more functional positions could be considered for further research.

Effect of increased relative stiffness of the lumbar spine on hamstring muscle stretching in individuals with a history of low back pain suspected to have a clinical lumbar instability: A randomized crossover design

BACKGROUND

Theoretically, lumbopelvic stabilization techniques during hamstring muscle stretching could increase lumbar stiffness relative to hamstring muscle in individuals with a history of low back pain and suspected clinical lumbar instability. However, evidence to support this theory is limited. This study aimed to 1) determine changes in lumbopelvic, lumbar, and hip motions, and hamstring muscle length after stretching exercises with lumbopelvic stiffening or relaxing techniques, and 2) compare those changes between techniques.

METHODS

This study used a randomized crossover design. Thirty-two participants with a history of low back pain and bilateral hamstring muscle tightness were recruited. The order of the first technique was randomly assigned. After a 2-day washout, participants were crossed over to the second technique. Motion data during active forward trunk bending and bilateral hamstring muscle length during passive knee extension were collected pre- and post-intervention.

FINDINGS

Significant increases (P < 0.05) were found in bilateral hamstring muscle length for both techniques. However, stiffening technique demonstrated a significant decrease in lumbar motion (P < 0.05) and increase in hip motion (P < 0.05), while relaxing technique demonstrated trends showing increases in lumbar and hip motions (P = 0.134 and 0.115, respectively). The findings showed significantly greater improvement (P < 0.05) in lumbar and hip motions with stiffening technique.

INTERPRETATION

The findings suggest increased relative stiffness of the lumbar spine during hamstring muscle stretching can specifically lengthen bilateral hamstring muscle and decrease excessive lumbar motion. This stiffening technique may prevent excessive movement of the lumbar spine, thereby reducing the risk of recurrent low back pain.

The feasibility and impact of instrument-assisted manual therapy (IAMT) for the lower back on the structural and functional properties of the lumbar area in female soccer players: a randomised, placebo-controlled pilot study design

BACKGROUND

Myofascial (self-)treatments, such as foam rollers to therapeutic instruments in manual therapy, are utilized increasingly in prevention and therapy in healthy people, athletes, and patients suffering from chronic back pain. However, there is limited knowledge about the effectiveness of treatment and the underlying mechanisms of myofascial therapies, especially for instrument-assisted manual therapy (IAMT). Therefore, this pilot study will investigate the feasibility and impact of IAMT for the lumbar area compared with heat application and placebo treatment as a basis for calculating the sample size for further full studies. The primary outcomes will be a critical analysis of the feasibility of the measurement protocol in terms of time economy and expressiveness and of the short- and long-term effects on shear motion of the single tissue layers of the lower back obtained through ultrasound imaging. Secondary outcomes will include thickness and compressibility of the lumbar structures and flexibility of the dorsal structures, indentometry, and superficial skin temperature.

METHODS

A minimum of 60 healthy, competitive 15-35-year-old female soccer players will be recruited and randomised into three groups. Short-term effects of IAMT on thoracolumbar structures will be compared with heat application and pressure-less placebo treatment. Long-term effects in the IAMT group will be tested after nine further interventions over a 5-week period (2×/week) and compared with the placebo group, which will not receive further treatments but will serve as a control. Intermediate and final testing of both groups will occur in weeks three and five.

DISCUSSION

This pilot study will assess the feasibility and the impact of IAMT for the lower back particularly by examining the structural and functional properties of myofascial tissue using diagnostic ultrasound. These outcomes could evaluate the feasibility of the measurements used, shall build a basis for sample size calculation of further full studies, and might generate a greater understanding of myofascial therapies, especially IAMT, for the lower back and its benefits. If this approach proves to be practicable, next steps will be further full studies with soccer players, other sports, and patients with low back pain.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS00012252) 20.06.2018; retrospectively registered.

Importance and Diagnosis of Flexibility Preparation of Male Sport Climbers

The objective of the study was to verify the relationships between sport skill levels and to identify the tests that accurately diagnose flexibility of sport climbers. This study examined 60 competitive advanced–higher elite male 7b–9a redpoint (RP) climbers. The athletes performed commonly used flexibility tests (stand-and-reach, straddle sit, straddle stand) and climbing-specific flexibility tests. Significant correlations were found between sport skill levels for the straddle stand test (r = −0.48) and the straddle sit test (r = −0.41). No significant correlations were observed between climbing-specific flexibility tests and sports skill level of climbers. Hip abduction evaluated using the straddle sit and straddle stand tests were significantly correlated with sports skill level and thus can be approached as a tool to diagnose flexibility of climbers. Flexibility is very specific and difficult to diagnose in climbing, but it should be developed.

Comparison between 4 weeks passive static stretching and proprioceptive neuromuscular facilitation programmes on neuromuscular properties of hamstring muscles: a randomised clinical trial

Background/aims

Studies have shown the efficacy of stretching to increase the hip flexion range of motion but studies regarding its effects are not unanimous about the most efficient technique. The aim of this study was to compare the effect of two stretching techniques on the neuromuscular properties of the hamstring muscles.

Methods

A total of 18 women (aged 24 ± 2.52 years old) participated, and were divided into three groups: a control group, a passive static stretching group and a propioceptive neuromuscular facilitation stretching group. Evaluations of variables of the hamstring muscles were performed before and after the training period. The intervention was carried out for 30 seconds, three times a week for a total of 4 weeks.

Results

A significant difference was found in the range of motion in the passive static stretching group (pre=80.8° [±11.0] and post=94.5° [±10.2]; t(5)=−3.755; P=0.013) and in concentric torque (passive static stretching group – pre=66.3 Nm [±12.9] and post=70.0 Nm [±8.1]; t(5)=−1.267; P=0.023; propioceptive neuromuscular facilitation stretching group – pre=79.1 Nm [±12.7] and post=83.5 Nm [±11.6]; t(5)=−1.917; P=0.014; control group – pre=71.1 Nm [±10.1] and post=74.1 Nm [±14.6]; t(5)=−1.275; P=0.003).

Conclusions

Passive static stretching was superior to propioceptive neuromuscular facilitation when comparing the increase range of motion in hip flexion, even without neural and structural changes in hamstring muscles after a 4-week period.

Superficial heat administration and foam rolling increase hamstring flexibility acutely; with amplifying effects

OBJECTIVES

To compare the objective and subjective efficacy of three treatments on acute hip-flexion range of motion (ROM).

DESIGN

Assessor-blind, randomized within-subject cross-over.

SETTING

University athletic training clinic.

PARTICIPANTS

Twenty-two female collegiate lacrosse and soccer athletes.

MAIN OUTCOME MEASURES

The passive straight-leg-raise (PSLR) was used to measure acute hip-flexion ROM pre- and post foam rolling (FR), superficial heating (SH), combination (SH + FR) and control treatments. A seven-point Likert scale statement measured the perceived effectiveness of each treatment.

RESULTS

Superficial heat (+10.4%, ES = 0.78), FR (+7.26%, ES = 0.52), and SH + FR treatment (+12.9%, ES = 1.26) improved hip ROM when compared to the control (+2.4%, ES = 0.24) (all p < 0.001). The SH + FR treatment resulted in a greater improvement in hip ROM compared to FR (p = 0.001, ES = 0.95), whereas no significant difference was observed between the SH and FR (p = 0.083, ES = 0.68) or SH and SH + FR treatment (p = 0.270, ES = 0.43). SH + FR was perceived as more effective than FR (p = 0.033, ES = 1.21), but not SH (p = 0.193, ES = 0.63). However, only a moderately positive correlation (r = 0.508) between objective and subjective measures of hamstring flexibility was found.

CONCLUSIONS

All treatments significantly improve hamstring flexibility with SH + FR being the most effective. Rehabilitation professionals should practice caution when relying on athlete perception and should prescribe treatments on an individual basis.

Patellofemoral Pain

Patellofemoral pain (PFP) is a common musculoskeletal-related condition that is characterized by insidious onset of poorly defined pain, localized to the anterior retropatellar and/or peripatellar region of the knee. The onset of symptoms can be slow or acutely develop with a worsening of pain accompanying lower-limb loading activities (eg, squatting, prolonged sitting, ascending/descending stairs, jumping, or running). Symptoms can restrict participation in physical activity, sports, and work, as well as recur and persist for years. This clinical practice guideline will allow physical therapists and other rehabilitation specialists to stay up to date with evolving PFP knowledge and practices, and help them to make evidence-based treatment decisions. J Orthop Sports Phys Ther. 2019;49(9):CPG1-CPG95. doi:10.2519/jospt.2019.0302.

Measurement of the cross-sectional area of the hamstring muscles during initial and stretch positions with gravity magnetic resonance imaging

[Purpose] We aimed to investigate the change rate in the cross-sectional area of each hamstring component to evaluate muscle extensibility and to contribute to the studies on hamstring strain prevention. [Participants and Methods] Fifteen healthy young males volunteered to participate in this study. They performed a knee extension test. For the measurements, we used multi-posture magnetic resonance imaging (gravity magnetic resonance imaging), the open shape of which allows performing body scanning in various positions. We measured the maximum cross-sectional area of the hamstring during the initial and stretch positions from the obtained images. Then, for each muscle, we calculated the maximum cross-sectional area change rate relative to the initial position. [Results] For all hamstring muscles, the maximum cross-sectional area during stretching was significantly smaller than that in the initial position. The maximum cross-sectional area change rate of the semimembranosus was significantly smaller than that of the other 3 muscles (there were no significant differences among these 3 muscles). [Conclusion] The results suggest that the semimembranosus has higher resistance to morphological change than the other muscles, which could be an important limiting factor for the extensibility of the hamstring muscle group.

Neural gliding and neural tensioning differently impact flexibility, heat and pressure pain thresholds in asymptomatic subjects: A randomized, parallel and double-blind study

OBJECTIVE

To compare the effect of neural gliding and tensioning on hamstring flexibility, nerve function (heat and cold thresholds) and pain sensitivity (pain intensity and pressure pain threshold) of the mobilized and non-mobilized lower limbs at post-intervention and 24 h follow up.

DESIGN

Randomized, parallel and double blinded trial.

SETTING/PARTICIPANTS

Forty-eight asymptomatic participants.

INTERVENTION(S)

Participants received neural gliding (n = 23) or tensioning (n = 25). Main Outcome Measures - Straight leg raising (SLR; in degrees), heat and cold threshold (ºC), pressure pain threshold (PPT; in Kgf) and pain intensity (visual analogue scale), taken at baseline, post-intervention and at 24 h follow up.

RESULTS

There was a significant interaction between time, intervention and limb for SLR (F2,45 = 3.83; p = 0.029). A significant interaction between time and intervention for PPT (F2,45 = 3.59; p = 0.036) and heat threshold (F2,45 = 5.10; p = 0.01). A significant effect of time (F2,45 = 9.42; p < 0.001) and of limb (F1,46 = 4.78; p = 0.035) for pain intensity during SLR, and a significant effect of time (F2,45 = 3.65; p = 0.034) for pain intensity during PPT.

CONCLUSION

Gliding and tensioning had similar and positive effects for flexibility in the mobilized limb, but tensioning was superior for the non-mobilized limb. Gliding was superior to tensioning for pressure pain and heat thresholds.

Passive elastic contribution of hip extensors to joint moments during walking in people with low back pain

BACKGROUND

It has been found that alterations in passive muscle properties may be associated with low back pain, and these may be responsible for the altered gait parameters often observed in subjects with back pain. The purpose of the present study was to assess total hip and passive hip extensor moments in people with or without low back pain during the hip flexion component of walking.

METHODS

52 subjects volunteered for this study (low back pain group, n = 25 (male n = 13, female n = 12), control group, n = 27 (male n = 15, female n = 12)). Passive hip moments were calculated using an adapted force transducer during supine testing. A biomechanical model and predictive equation were used to calculate passive hip moments during walking. Total hip moments were calculated with the use of a 9 camera, 3-D motion-capture system.

FINDINGS

Independent samples t-tests demonstrated no significant differences between groups for gait parameters or hip or knee angles. Results of the ANOVAs demonstrated significant differences in passive hip flexor moments during the second half of hip flexion (P < 0.05).There were also significant differences in hip power and work done during peaks of power absorption and the second peak of power generation (P < 0.05).

INTERPRETATION

The present data demonstrates that subjects with low back pain have altered passive hip extensor and total power and work done during walking compared with healthy controls. Biomechanical models should include individual measurements of passive joint moments.

Prefabricated foot orthoses compared to a placebo intervention for the treatment of chronic nonspecific low back pain: a study protocol for a randomised controlled trial

BACKGROUND

Prefabricated foot orthoses are used to treat chronic nonspecific low back pain, however their effectiveness and potential mechanism of action is unclear. The primary aims of the study are to investigate the effectiveness of prefabricated foot orthotic devices for reducing pain and improving function in people with chronic nonspecific low back pain over 52 weeks.

METHODS

This study is a participant and assessor blinded, parallel-group, superiority randomised (1:1) controlled trial. The study will recruit 60 participants aged 18 to 65 years with chronic nonspecific low back pain. Participants will undergo randomisation to a control group (The Back Book) or an intervention group (prefabricated foot orthoses and The Back Book). The primary outcome measures will be change in pain and function from baseline to 12 (primary time point), 26, and 52 weeks. Secondary outcome measures include: gluteus medius muscle activity and transversus abdominis muscle thickness from baseline to 12 weeks, physical activity over 12, 26, and 52 weeks, and correlation between foot type and change in measures of pain and function. Number of hours per day and week that the prefabricated orthoses are worn, as well as, adverse events will be self-reported by participants. Data will be analysed using the intention-to-treat principle.

DISCUSSION

This trial will primarily evaluate the effectiveness of prefabricated foot orthotic devices for reducing pain and improving function in people with chronic nonspecific low back pain over 52 weeks. It is expected that this study will provide clinicians and researchers with an understanding of the role that prefabricated foot orthoses may have in the treatment of chronic nonspecific low back pain and a potential mechanism of action, and whether foot type influences the outcome.

TRIAL REGISTRATION

ACTRN12618001298202.

Effects of Foam Rolling on Range of Motion, Peak Torque, Muscle Activation, and the Hamstrings-to-Quadriceps Strength Ratios

Madoni, SN, Costa, PB, Coburn, JW, and Galpin, AJ. Effects of foam rolling on range of motion, peak torque, muscle activation, and the hamstrings-to-quadriceps strength ratios. J Strength Cond Res 32(7): 1821-1830, 2018-To examine the effects of foam rolling (FR) on range of motion (ROM), peak torque (PT), hamstrings-to-quadriceps (H:Q) ratios, and muscle activation. Twenty-two recreationally active women (mean age ± SD = 21.55 ± 1.82 years, 161.91 ± 6.58 cm, 61.47 ± 10.54 kg) volunteered for this study. Participants performed pre- and posttests analyzing PT and surface electromyography (EMG) of their dominant limb, completing maximal knee extension and flexion at 3 different velocities. Participants foam rolled the hamstrings muscles or sat for the control condition between the pre- and posttests. Hamstrings ROM increased in the FR condition from (mean ± SE) 123.23 ± 3.49 to 126.41 ± 3.62° (p < 0.001) and decreased in the control condition from 118.82 ± 4.25 to 117.95 ± 4.29° (p = 0.013). Concentric hamstrings PT and conventional H:Q ratios decreased after both conditions, with smaller decreases after FR (p ≤ 0.05). No significant changes were found for eccentric hamstrings PT, eccentric hamstrings EMG, or functional H:Q ratios (p > 0.05). Foam rolling resulted in greater changes in hamstrings ROM without creating a deficit in PT or muscle activation when compared with the control group. When compared with other methods of stretching, FR may be beneficial in increasing ROM without decreasing functional H:Q ratios.

Physical Fitness Predictors of a Warrior Task Simulation Test

Huang, H-C, Nagai, T, Lovalekar, M, Connaboy, C, and Nindl, BC. Physical fitness predictors of a warrior task simulation test. J Strength Cond Res 32(9): 2562-2568, 2018-The warrior task simulation test (WTST) has been developed in an attempt to better assess physical fitness required for soldiers to perform battlefield tasks and drills to determine whether laboratory-based measurements of physical fitness components could be used to predict the WTST. Forty-three healthy and physically active men participated in 2 sessions: the WTST and laboratory testing. The WTST comprised 282-m run, low hurdles, high crawl, casualty drag, balance beam, point-aim-move, 100-yard sprint, and agility sprint with participants wearing combat boots, uniform, helmet, and dummy rifle. The laboratory testing included assessments of participants' muscular strength and endurance, postural stability, aerobic capacity, anaerobic capacity, flexibility, body fat, fat-free mass, and agility. Correlation and simple and multiple linear regression analyses were used to analyze the relationship between the WTST and laboratory testing and predict the WTST, respectively (p < 0.05). The correlation and the simple linear regression analyses revealed that anaerobic capability, aerobic capacity, body fat, agility, and muscular endurance correlated with (r = 0.35-0.59) and accounted for 12-34% of the variance in (R = 0.12-0.34) the WTST performance (p < 0.05). The final model included aerobic capacity, agility, fat-free mass, muscular endurance, and body fat (R = 0.52, p < 0.001). The current results highlighted the importance of several components of physical fitness in simulated battlefield tasks and drills (assessed by the WTST). In particular, anaerobic capacity, aerobic capacity, and body fat had the highest correlational and predictive values of the WTST. Additionally, skill-related components of physical fitness, such as agility and muscular endurance, should not be ignored, and they should be assessed and tracked with the above-mentioned components.

Hamstring and Ankle Flexibility Deficits Are Weak Risk Factors for Hamstring Injury in Professional Soccer Players: A Prospective Cohort Study of 438 Players Including 78 Injuries

BACKGROUND

Hamstring injuries remain a significant injury burden in sports such as soccer that involve high-speed running. It has repeatedly been identified as the most common noncontact injury in elite male soccer, representing 12% of all injuries. As the incidence of hamstring injuries remains high, investigations are aimed at better understanding how to prevent hamstring injuries. Stretching to improve flexibility is commonly used in elite-level sports, but risk factor studies have reported contradicting results, leading to unclear conclusions regarding flexibility as a risk factor for hamstring injuries.

PURPOSE

To investigate the association of lower limb flexibility with the risk of hamstring injuries in professional soccer players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

All teams (n = 18) eligible to compete in the premier soccer league in Qatar (Qatar Stars League [QSL]) underwent a comprehensive musculoskeletal assessment during their annual periodic health evaluation at Aspetar Orthopaedic and Sports Medicine Hospital in Doha, Qatar. Variables included passive knee extension and ankle dorsiflexion range of motion. A clustered multivariate Cox regression analysis was used to identify associations with the risk of hamstring injuries. Receiver operating characteristic (ROC) curves were calculated to determine sensitivity and specificity.

RESULTS

A total of 438 unique players (72.4% of all QSL players) competed for 601 player-seasons (148 players competed both seasons) and sustained 78 hamstring injuries. Passive knee extension range of motion (hazard ratio [HR], 0.97 [95% CI, 0.95-0.99]; P = .008) and ankle dorsiflexion range of motion (HR, 0.93 [95% CI, 0.88-0.99]; P = .02) were independently associated with the injury risk. The absolute differences between the injured and uninjured players were 1.8° and 1.4 cm, respectively, with small effect sizes ( d < 0.2). The ROC curve analyses showed an area under the curve of 0.52 for passive knee extension and 0.61 for ankle dorsiflexion, indicating failed to poor combined sensitivity and specificity of the 2 strength variables identified in the multivariate Cox regression analysis.

CONCLUSION

This study identified deficits in passive hamstring and ankle dorsiflexion range of motion as weak risk factors for a hamstring injury. These findings have little clinical value in predicting the risk of future hamstring injuries, and test results must therefore be interpreted cautiously in athletic screening.

The Cut-off Values for the Diagnosis of Hamstring Shortness and Related Factors

Background:

Hamstrings are one of the most frequently evaluated muscle groups for flexibility in the lower extremity. Passive and active knee extension angle values are used as an indirect indicator of hamstring flexibility. However, the lack of consensus on the cut-off values leads to the use of inconsistent angle values in determining the hamstring tightness.

Aims:

To establish the normative and cut-off values of the passive and active knee extension angles for healthy young adults and to determine the associated factors including the quadriceps strength.

Study Design:

A cross-sectional study.

Methods:

A total of 123 volunteer university students, aged 18-24 years, who met the inclusion criteria were included in this study. Passive and active knee extension assessments of the subjects were performed. Subsequently, on the next day, both knee extensor concentric muscle strength of the participants was measured in the isokinetic system. The knee extension angles and the knee extensor strength were recorded as the mean values of the right and the left sides.

Results:

Passive knee extension angles of 17.1°±9.1° and 9.8°±5.7° and active knee extension angles of 17.8°±9.1° and 13.4°±6° were described as normative values in men and women, respectively. The cut-off values for the diagnosis of hamstring shortness were as follows: passive knee extension angle >32.2° for males and >19.2° for females and active knee extension angle >33.0° for males and >23.4° for females. A significant positive correlation was observed between knee extension angles and isokinetic knee extensor muscle strength in all participants. The knee extension angle and hamstring flexibility were not affected by dominance.

Conclusion:

The knee extension angles of healthy young people seem to be lower than the results currently reported in the literature. There s a positive correlation between knee extension angles and isokinetic knee extensor muscle strength.

Associations of passive muscle stiffness, muscle stretch tolerance, and muscle slack angle with range of motion: individual and sex differences

Joint range of motion (ROM) is an important parameter for athletic performance and muscular injury risk. Nonetheless, a complete description of muscular factors influencing ROM among individuals and between men and women is lacking. We examined whether passive muscle stiffness (evaluated by angle-specific muscle shear modulus), tolerance to muscle stretch (evaluated by muscle shear modulus at end-ROM), and muscle slack angle of the triceps surae are associated with the individual variability and sex difference in dorsiflexion ROM, using ultrasound shear wave elastography. For men, ROM was negatively correlated to passive muscle stiffness of the medial and lateral gastrocnemius in a tensioned state and positively to tolerance to muscle stretch in the medial gastrocnemius. For women, ROM was only positively correlated to tolerance to muscle stretch in all muscles but not correlated to passive muscle stiffness. Muscle slack angle was not correlated to ROM in men and women. Significant sex differences were observed only for dorsiflexion ROM and passive muscle stiffness in a tensioned state. These findings suggest that muscular factors associated with ROM are different between men and women. Furthermore, the sex difference in dorsiflexion ROM might be attributed partly to that in passive muscle stiffness of plantar flexors.

Effect of remote myofascial release on hamstring flexibility in asymptomatic individuals - A randomized clinical trial

BACKGROUND

The existence of continuity between fascia and muscles that may be anatomically distant from each other is emphasized in the tensegrity principle. Despite evidence from in vitro studies, there is a dearth of literature concerning the in vivo behavior of these connections.

AIM

To compare the effect of Static Stretching (SS) of hamstrings with remote Myofascial Release (MFR) (bilateral plantar fascia and suboccipital region) and a combination of SS and remote MFR on hamstring flexibility. The secondary aim of this study was to investigate the difference between therapist administered and self-administered interventions.

DESIGN

Three arm assessor-blinded Randomized Clinical Trial (RCT).

PARTICIPANTS

Fifty-eight asymptomatic participants (16 Males; Mean age 22.69 ± 2.65 years).

METHOD

Participants with tight hamstrings defined by a passive Knee Extension Angle (KEA) > 20° were included in the study and were assigned to one of the three groups. Group A (n = 19) was SS, group B (n = 20) was remote MFR, group C (n = 19) was a combination group who received both SS and remote MFR. Seven sessions of therapist administered intervention were delivered over a period of 10 days, which was followed by a 2-week self-administered home program. KEA and Sit and Reach Test (SRT) were used as outcomes and measurements were performed at baseline, end of the seventh session and after atwo-week follow-up.

RESULTS

The results demonstrated that hamstring flexibility improved in all three groups after therapist administered interventions (p < 0.05), whereas, group C demonstrated additional benefits. None of the groups showed a statistically significant (p > 0.05) change in the KEA with self-intervention.

CONCLUSION

The findings of this study indicated that all three interventions were effective in improving hamstring flexibility in young asymptomatic individuals when performed by the therapist.

Patellofemoral pain in athletes: clinical perspectives

Patellofemoral pain (PFP) is a very common problem in athletes who participate in jumping, cutting and pivoting sports. Several risk factors may play a part in the pathogenesis of PFP. Overuse, trauma and intrinsic risk factors are particularly important among athletes. Physical examination has a key role in PFP diagnosis. Furthermore, common risk factors should be investigated, such as hip muscle dysfunction, poor core muscle endurance, muscular tightness, excessive foot pronation and patellar malalignment. Imaging is seldom needed in special cases. Many possible interventions are recommended for PFP management. Due to the multifactorial nature of PFP, the clinical approach should be individualized, and the contribution of different factors should be considered and managed accordingly. In most cases, activity modification and rehabilitation should be tried before any surgical interventions.

The effect of an 8-week stabilization exercise program on the lumbopelvic rhythm and flexion-relaxation phenomenon

BACKGROUND

Lumbar stabilization exercise programs should normalize the aberrant movements patterns often observed in patients with low back pain. This study aimed to determine the effect of an 8-week lumbar stabilization program on EMG/kinematics measures of the aberrant movement patterns in such patients. A secondary goal was to assess the 8-week test-retest reliability of these measures.

METHODS

The patients followed an 8-week lumbar stabilization program while no intervention was carried out on the controls. Before and after this period, kinematics of the spine along with the EMG of paraspinal muscles were recorded during trunk maximal flexion-extension. ANOVAs tested the effect of the intervention in the patients, relative to the controls. Within the patients, correlation of the EMG/kinematics measures with the change in disability and pain following the intervention was investigated.

FINDINGS

A significant reduction in pain (Hedges's g effect size=2.31) and improvement in function (g=1.74) was reported in the patients. While EMG/kinematics measures disclosed impairments in the patients at baseline compared to the controls, no change was observed over the intervention. Nevertheless, the change of lumbar range of motion was positively correlated (r=0.42; P=0.015) with the change in disability.

INTERPRETATION

Although pain and disability decreased following the intervention, the EMG/kinematics measures did not change concomitantly suggesting that the patients learned to stiffen the lumbar spine during the treatment, and this technique was applied even if pain and disability unequivocally decreased after the treatment, which would not necessarily be beneficial to the patient.

The treatment effect of hamstring stretching and nerve mobilization for patients with radicular lower back pain

[Purpose] In this paper, hamstring stretching and nerve mobilization are conducted on patients with radicular lower back pain, and changes to pain levels, pressure thresholds, angles of knee joint extension, and disorder levels of lower back pain were studied. [Subjects and Methods] The subjects were divided into two groups: one group conducted hamstring stretches and was comprised of 6 male and 5 female subjects, and the other group received nerve mobilization treatment and was comprised of 5 male and 6 female subjects. [Results] Pain level and the disorder index of lower back pain were significantly alleviated after the intervention in both groups. Pressure threshold and angles of knee extension were significantly increased after the intervention in both groups. Comparing the two groups, the alleviation of pain was more significant in the nerve mobilization group. [Conclusion] Patients with radicular lower back pain showed significant differences in pain level, pressure threshold, knee extension angle, and disorder index of lower back pain for both the hamstring stretching group and nerve mobilization group after the treatment. Hamstring stretching and nerve mobilization can be usefully applied for the therapy of patients with radicular lower back pain.

Acute effect of different time periods of passive static stretching on the hamstring flexibility

BACKGROUND

Several factors are associated with the presence of chronic low back pain; one of them is the flexibility of the hamstring muscles that influences the posture of the pelvic spine.

OBJECTIVE

Investigate the influence of two different time periods of passive static stretching on the flexibility of the hamstring.

METHODS

Forty-six physiotherapy students were divided into two groups performing stretching exercises: 30 s and 60 s duration. The collections consisted of: (1) pre-test: evaluation of the flexibility of the hip and knee, using a manual goniometer by means of the following tests: Straight Leg Raise Test (SLR), Passive Hip Flexion Test (PHFT) and Modified Knee Extension Test (MKET), (2) intervention: stretching with different runtimes, (3) post-test: reappraisal of flexibility, conducted immediately after the intervention.

RESULTS

Significant difference was observed intra groups, group that did stretching exercises lasting 30 seconds (G30) (SLR p = 0.000. PHFT p = 0.003 and MKET p = 0.000) and group that did stretching exercises lasting 60 seconds (G60) (SLR p = 0.000. PHFT p = 0.001 and MKET p = 0.002). Comparing the groups, no significant difference was found (SLR p = 0.307; PHFT p = 0.904; MKET p = 0.132).

CONCLUSION

Thus it can be inferred that 30 seconds are sufficient for increased flexibility of young women. Therefore the time-treatment sessions can be optimized. Only the acute effect of stretching was observed; further investigation of the long-term effect is required.

No Relationship Between Hamstring Flexibility and Hamstring Injuries in Male Amateur Soccer Players: A Prospective Study

BACKGROUND

In soccer, although hamstring flexibility is thought to play a major role in preventing hamstring injuries, the relationship between hamstring flexibility and hamstring injuries remains unclear.

PURPOSE

To investigate the relationship between hamstring flexibility and hamstring injuries in male amateur soccer players.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This study included 450 male first-class amateur soccer players (mean age, 24.5 years). Hamstring flexibility was measured by performing the sit-and-reach test (SRT). The relationship between hamstring flexibility and the occurrence of hamstring injuries in the following year, while adjusting for the possible confounding effects of age and previous hamstring injuries, was determined with a multivariate logistic regression analysis.

RESULTS

Of the 450 soccer players, 21.8% reported a hamstring injury in the previous year. The mean (±SD) baseline score for the SRT was 21.2 ± 9.2 cm. During the 1-year follow-up period, 23 participants (5.1%) suffered a hamstring injury. In the multivariate analysis, while adjusting for age and previous injuries, no significant relationship was found between hamstring flexibility and hamstring injuries ( P = .493).

CONCLUSION

In this group of soccer players, hamstring flexibility (measured with the SRT) was not related to hamstring injuries. Age and previous hamstring injuries as possible confounders did not appear to influence this relationship. Other etiological factors need to be examined to further elucidate the mechanism of hamstring injuries.