A literature review of studies evaluating gluteus maximus and gluteus medius activation during rehabilitation exercises

Comparison of erector spinae and gluteus medius muscle thickness and activation in individuals with and without low back pain

BACKGROUND

Dysfunctional patterns of the erector spinae (ES) and gluteus medius (GM) muscles often accompany episodes of low back pain (LBP). Rehabilitative ultrasound imaging (RUSI) has been used to measure ES and GM muscle thickness, however such measurements have not been compared in individuals with and without LBP.

OBJECTIVES

To compare ES and GM muscle thickness and change in thickness utilizing RUSI in individuals with and without LBP.

DESIGN

Cross-sectional comparison.

METHODS

A volunteer sample of 60 adults with (n = 30) and without (n = 30) LBP was examined. Thickness measurements of the ES and GM at rest and during contraction were obtained by using RUSI during a single session. Statistical comparison was performed using ANCOVA. The demographic variable age was used as a covariate in the primary comparative analysis.

RESULTS

Mean difference for age between groups was 5.4 years (95% CI: 1.85, 8.94, p = 0.004). Average ODI score was 32.33±6.58 and pain level of 5.39±0.73 over the last 24 h in the symptomatic group. There was a statistically significant difference in the percent thickness change in both the ES, mean difference = -3.46 (95% CI: -6.71, -0.21, p = 0.039) and GM, mean difference = -1.93 (95% CI: -3.85, -0.01, p = 0.049) muscles between groups.

CONCLUSIONS

Individuals with LBP may have reduced percent thickness change of the ES and GM muscles when compared to asymptomatic individuals.

Effects of Ankle Position While Performing One- and Two-Leg Floor Bridging Exercises on Core and Lower Extremity Muscle Recruitment

Given there are no known studies which have examined multiple lower extremity muscles between different ankle positions during bridging activities, the objective was to assess how employing two different ankle positions (PF versus DF) while performing five common bridging exercises (three bipedal and two unipedal) used in rehabilitation and athletic performance affect core and select lower extremity muscle EMG recruitment. Twenty healthy subjects performed a 5 s isometric hold during five two- and one-leg bridge exercises: (1) on right leg with left knee to chest (1LB-LFlex); (2) on right leg with left knee extended (1LB-LExt); (3) standard two-leg bridge (2LB); (4) two-leg bridge with resistance band around knees (2LB-ABD); and (5) two-leg bridge with ball between knees (2LB-ADD). Surface electromyographic (EMG) data were collected using a Noraxon Telemyo Direct Transmission System from fourteen muscles: (1) three superficial quadriceps (VM, VL, and RF); (2) three hip abductors (TFL, GMED, and GMAX); (3) medial hamstrings (ST) and lateral hamstrings (BF); (4) hip adductors (ADD); (5) erector spinae (ES); (6) latissimus dorsi (LATS); (7) upper rectus abdominis (RA); and (8) external oblique (EO) and internal oblique (IO). EMG data were normalized by maximum voluntary isometric contractions (MVICs). A paired t-test (p < 0.01) was used to assess differences in normalized mean EMG activities between DF and PF for each exercise. EMG activities were significantly greater in DF than PF for the (a) VM, VL, and RF during 1LB-LFlex; (b) ADD during 1LB-LFlex, 1LB-LExt; (c) EO during 1LB-LFlex; and (d) IO during 1LB-LFex. In contrast, EMG activities were significantly greater in PF than DF for ST and BF during all five bridge exercises. Bridging with PF (feet flat) was most effective in recruiting the hamstrings, while bridging with DF (feet up) was most effective in recruiting the quadriceps, hip adductors, and internal and external obliques.

Intramuscular Neural Distribution of the Gluteus Maximus Muscle: Diagnostic Electromyography and Injective Treatments

INTRODUCTION

The purpose of this study was to investigate neural patterns within the gluteus maximus (Gmax) muscle to identify optimal EMG placement and injection sites for botulinum toxin and other injectable agents.

METHODS

This study used 10 fixed and 1 non-fixed adult Korean cadavers. Intramuscular arborization patterns were confirmed in the cranial, middle, and caudal segments of 20 Gmax muscles using Sihler staining. Ultrasound images were obtained from one cadaver, and blue dye was injected using ultrasound guidance to confirm the results.

RESULTS

The intramuscular innervation pattern of the Gmax was mostly in the middle part of this muscle. The nerve endings of the Gmax are mainly located in the 40-70% range in the cranial segment, the 30-60% range in the middle segment, and the 40-70% range in the caudal segment.

DISCUSSION

Addressing the spasticity of the gluteus maximus requires precise, site-specific botulinum toxin injections. The use of EMG and other injection therapies should be guided by the findings of this study. We propose that these specific sites, which correspond to areas with the densest nerve branches, are the safest and most efficient locations for both botulinum toxin injections and EMG procedures.

The association between lateral hip muscle size/intramuscular fat infiltration and hip strength in active young adults with long standing hip/groin pain

OBJECTIVES

To investigate associations between lateral hip muscle size/intramuscular fat infiltration (MFI) and hip strength in active young adults with longstanding hip/groin pain.

DESIGN

Cross-sectional study.

SETTING

University/Clinical.

PARTICIPANTS

Sub-elite soccer and Australian Football players (n = 180; 37 female) with long standing hip/groin pain.

MAIN OUTCOME MEASURES

Muscle size (volume) and MFI of gluteus maximus, medius, and minimis, and tensor fascia latae (TFL) were assessed using magnetic resonance imaging. Isometric hip strength was measured with handheld dynamometry. Associations between muscle size/MFI were assessed using linear regression models, adjusted for body mass index and age, with sex-specific interactions.

RESULTS

Positive associations were identified between lateral hip muscle volume and hip muscle strength, particularly for gluteus maximus and gluteus minimus volume. For all muscles, hip abduction was associated with an increase in strength by up to 0.69 N (R2 ranging from 0.29 to 0.39). These relationships were consistent across sexes with no sex interactions observed. No associations were found between MFI and strength measures.

CONCLUSION

Greater lateral hip muscle volumes are associated with greater hip strength in active young adults with long standing hip/groin pain, irrespective of sex. Gluteus maximus and minimus volume showed the most consistent relationships with hip strength across multiple directions.

Influence of hip flexion angle on strength and gluteal muscle activities in the clinical pilates clamshell exercise

The study aimed to investigate the presence of directional preference using the Clinical Pilates method of clamshell exercise among relatively healthy young adults, and the influence of hip flexion angles on maximum isometric strength (handheld dynamometer) and muscle activities (electromyography). The clamshell assessment involves testing in varying angles of hip flexion (0°, 30°, 60° and 90°) and 21 participants were tested. Directional preferences in the transverse and anteroposterior axes of movements were present among the participants. Gluteus medius activation was highest in the non-problem side across all hip flexion angles. In contrast, the problem side showed dysfunction of the gluteus medius, especially at the 60° hip flexion angle, 0.89 unit (ratio of maximal voluntary isometric contraction) reduction per 1 N force exerted, 95% CI -1.69 to -0.09, p = 0.031. Comparison against the non-problem side found gluteus medius activity lower on the problem side, mean difference (SD) was 26.2 (56.1), p = 0.045. Therefore, directional preference is not limited to people with injuries and can exist in healthy individuals or people who have recovered from injuries. The gluteus medius was identified to be dysfunctional on the problem side and Clinical Pilates clamshell assessment is potentially useful in assessing for motor coordination impairment.

Influence of motor imagery training on hip abductor muscle strength and bilateral transfer effect

Motor imagery training could be an important treatment of reduced muscle function in patients and injured athletes. In this study, we investigated the efficacy of imagery training on maximal force production in a larger muscle group (hip abductors) and potential bilateral transfer effects. Healthy participants (n = 77) took part in two experimental studies using two imagery protocols (∼30 min/day, 5 days/week for 2 weeks) compared either with no practice (study 1), or with isometric exercise training (study 2). Maximal hip abduction isometric torque, electromyography amplitudes (trained and untrained limbs), handgrip strength, right shoulder abduction (strength and electromyography), and imagery capability were measured before and after the intervention. Post intervention, motor imagery groups of both studies exhibited significant increase in hip abductors strength (∼8%, trained side) and improved imagery capability. Further results showed that imagery training induced bilateral transfer effects on muscle strength and electromyography amplitude of hip abductors. Motor imagery training was effective in creating functional improvements in limb muscles of trained and untrained sides.

Etiology and Prevention of Common Injuries in Golf

ABSTRACT

Golf is a popular sport played by individuals of varying age and skillsets. The golf swing is unique and complex, creating potential for various musculoskeletal injuries in both amateur and professional golfers. Understanding the basic biomechanics of the golf swing and its relation to injury etiology can assist the health care provider in recognizing and preventing musculoskeletal injuries secondary to golf. Most injuries occur in the upper limb and the lumbar spine. This review describes musculoskeletal pathologies seen in golfers with respect to anatomic area and golf swing biomechanics, while summarizing effective prevention strategies and swing modifications to address these potential injuries.

The relative activation of pelvic floor muscles during selected yoga poses

BACKGROUND

Individuals with pelvic floor muscle (PFM) dysfunction can benefit from core stabilization exercises. Yoga is a popular activity that can generate moderate to high trunk activity and has been shown to benefit this patient population. No data exist regarding PFM activity during yoga. Determining PFM activity will provide important information for developing an evidence-based exercise program.

OBJECTIVES

To determine the relative activation of the PFM during select yoga poses.

STUDY DESIGN

Cross-sectional design.

METHODS

Perianal surface EMG sensors were used to capture levator ani (LA) activation. Peak activity of a maximum voluntary isometric contraction (MVIC) represented 100% activity. For testing, subjects held the following poses for 30 s: locust; modified side plank; side angle; and hands-clasped front plank. The average EMG activity, expressed as a 100% percent of the MVIC (%MVIC), from 5 to 25 s of each pose was analyzed.

RESULTS

Subjects generated the most activity (63.5 %MVIC) during the locust. Side angle (35.3 %MVIC) required greater activity than the side (29.1 %MVIC) and front planks (26.3 %MVIC). Locust activity was significantly greater (P < 0.001) than all poses; side angle activity was significantly greater (P < 0.01) than the front and side planks.

CONCLUSION

LA activation during locust was very high and sufficient for strength gains. LA activation during side angle, front plank, and side plank would be best for improving endurance and/or neuromuscular control of the PFM. Findings from this study showed differing levels of PFM activation across yoga poses that may benefit patients with pathology associated with PFM dysfunction.

Correlation Between Atrophy of the Gluteus Medius Muscle and Symptoms of Lumbar Spinal Stenosis

OBJECTIVE

Lower muscular weakness and gait disturbance are typical lumbar spinal stenosis (LSS) symptoms. Gait initiation and standing balance function are dependent on hip muscle groups, particularly gluteus medius (GMed). However, alterations to GMed in patients with LSS have not been studied. Therefore, we evaluated the impact of LSS on GMed in this study.

METHODS

This study included 96 participants divided into the LSS and non-LSS groups. A total of 48 patients with LSS and unilateral buttock pain underwent T2-weighted magnetic resonance imaging of GMed, and 48 age- and sex-matched controls formed the control group. Differences between the cross-sectional areas (CSAs) on both sides of GMed were compared between the 2 groups. Additionally, correlations among patient characteristics, clinical evaluation, and radiological measurement data with a decrease in the CSA of GMed were assessed in the LSS group.

RESULTS

A significant difference was observed in the bilateral discrepancy of the GMed CSA between the LSS and non-LSS groups. For patients with LSS with unilateral buttock pain, 81% had reduced CSA of GMed. Regression analysis revealed that buttock pain was an independent factor related to GMed atrophy.

CONCLUSIONS

The degree of GMed atrophy is related to symptoms of LSS. Spine surgeons should be aware of the risk of GMed atrophy in patients with LSS with unilateral buttock pain.

Comparing the effects of ankle integral and conventional physiotherapy on pain, range of motion, balance, disability, and treatment effectiveness in patients with chronic ankle instability: Randomized controlled trial

OBJECTIVE

To compare the effects of ankle integral and conventional physiotherapy on pain, range of motion, balance, disability, and treatment effectiveness in patients with chronic ankle instability (CAI).

DESIGN

Two-arm, parallel-group, randomized, double-blind, controlled trial.

PARTICIPANTS

60 patients with unilateral CAI.

INTERVENTION

integral physiotherapy (n = 30) or conventional physiotherapy (n = 30).

OUTCOMES

Visual Analog Scale (VAS), dorsiflexion and plantarflexion range of motion, Star Excursion Balance Test (SEBT), Single Leg Hop (SLH) test, Foot and Ankle Outcome Score (FAOS), Lower Extremity Functional Score (LEFS), global rating of change, were gathered pre and post-intervention.

RESULTS

The ANOVA results revealed statistically significant interaction for FAOS, and LEFS outcome measures (P < 0.05) and the mean change results showed there were a favorable clinical difference incline toward the integral group (mean_integral = 20.14 (14.95-25.37), mean_Conventional = 29.46 (24.09-34.83)). There were no interactions between group and time among other outcome measures (P > 0.05). The group main effect did not show any statistical significance (P > 0.05).

CONCLUSION

Hip strengthening and balance exercises added to ankle rehabilitation could be more favorable on improving the patients' functional ability.

Electromyographic analysis of the three subdivisions of gluteus medius during two different exercises: Wall press exercise and figure-of-four position

BACKGROUND

Gluteus medius (GM) is a segmented muscle involving three muscular subdivisions. Rehabilitation exercises has been suggested to strengthen specific subdivisions.

OBJECTIVE

This study aimed to evaluate muscular activation of the anterior, middle, and posterior subdivisions of the GM during two different exercises.

METHODS

A total of 28 healthy active subjects participated in this study. Muscle activity using surface electromyography was recorded for the three GM subdivisions during figure-of-four position (FFP) and wall press (WP). Non-parametric Kruskal-Wallis test was used to detect differences between GM subdivisions on each exercise and the Mann-Whitney U test was used to compare muscular activation across exercises.

RESULTS

There were statistically significant differences (P< 0.001) in all GM subdivision during FFP and WP exercises. Both exercises showed greater activation of the posterior subdivision than the middle and anterior subdivisions, with the WP causing highest activation of the posterior subdivision.

CONCLUSION

In line with the WP exercise, the FFP produces sufficient activity to provide potential strength gains on the posterior subdivision and could be a viable option to include in the early stages of the rehabilitation process. Clinicians may use this information to make more informed decisions about exercise selection for strengthening specific GM subdivision.

Movement retraining programme in young soccer and rugby football players: A feasibility and proof of concept study

INTRODUCTION

Movement screening to identify abnormal movement patterns can inform development of effective interventions. The primary objective of this study was to evaluate the feasibility of using a movement screening tool in combination with a tailored movement control retraining programme in young soccer and rugby football players. A secondary objective was to investigate changes in movement control patterns post-intervention, to provide proof of concept (PoC) for movement retraining.

METHODS

52 male amateur players, including 34 soccer players (mean age 15 ± 2 years) and 18 rugby players (mean age 15 ± 1 years) participated. They were screened for movement control ability using a shortened version of the Hip and Lower Limb Movement Screening (Short-HLLMS) and completed an eight-week movement control retraining programme. Evaluation of feasibility included consent from players invited, adherence, attendance at the exercise sessions, drop-out and adverse events. Short-HLLMS total score and The Copenhagen Hip and Groin Outcome Score (HAGOS) were analysed to provide PoC for retraining movement control.

RESULTS

feasibility outcomes were favourable. Significant statistical changes occurred post-intervention in the Short-HLLMS total score (paired-samples t-test) and in three HAGOS subscales (symptoms, physical function in daily living and in sport and recreation) (Wilcoxon-Signed Rank Test) in both groups.

CONCLUSIONS

Feasibility of using the Short-HLLMS in combination with a movement control retraining programme in soccer and rugby players was promising. The data provided PoC for the potential application of a shortened version of the HLLMS to evaluate changes in movement control and to inform targeted motor control programmes.

Leaning the Trunk Forward Decreases Patellofemoral Joint Loading During Uneven Running

ABSTRACT

AminiAghdam, S, Epro, G, James, D, and Karamanidis, K. Leaning the trunk forward decreases patellofemoral joint loading during uneven running. J Strength Cond Res 36(12): 3345-3351, 2022-Although decline surfaces or a more upright trunk posture during running increase the patellofemoral joint (PFJ) contact force and stress, less is known about these kinetic parameters under simultaneous changes to the running posture and surface height. This study aimed to investigate the interaction between Step (10-cm drop-step and level step) and Posture (trunk angle from the vertical: self-selected, ∼15°; backward, ∼0°; forward, ∼25°) on PFJ kinetics (primary outcomes) and knee kinematics and kinetics as well as hip and ankle kinetics (secondary outcomes) in 12 runners at 3.5 ms -1 . Two-way repeated measures analyses of variance ( α = 0.05) revealed no step-related changes in peak PFJ kinetics across running postures; however, a decreased peak knee flexion angle and increased joint stiffness in the drop-step only during backward trunk-leaning. The Step main effect revealed significantly increased peak hip and ankle extension moments in the drop-step, signifying pronounced mechanical demands on these joints. The Posture main effect revealed significantly higher and lower PFJ kinetics during backward and forward trunk-leaning, respectively, when compared with the self-selected condition. Forward trunk-leaning yielded significantly lower peak knee extension moments and higher hip extension moments, whereas the opposite effects occurred with backward trunk-leaning. Overall, changes to the running posture, but not to the running surface height, influenced the PFJ kinetics. In line with the previously reported efficacy of forward trunk-leaning in mitigating PFJ stress while even or decline running, this technique, through a distal-to-proximal joint load redistribution, also seems effective during running on surfaces with height perturbations.

Effects of Kinesio Taping and Rigid Taping on Gluteus Medius Muscle Activation in Healthy Individuals: A Randomized Controlled Study

BACKGROUND

Gluteus medius muscle (GMed) dysfunctions may be associated with pain and functional problems in the lumbar spine and lower limbs. The study sought to assess the effects of applying kinesio taping (KT) and rigid taping (RT) on GMed in the dominant leg of healthy individuals. Furthermore, an attempt was made to indicate which of the applied exercises brought about the greatest activation of GMed.

METHODS

The study included 90 individuals, with an average age of 21.79. The participants were randomly assigned to one of three groups: kinesio tape (KT), rigid tape (RT) and placebo tape (C). GMed activation was assessed using sEMG during the performance of such exercises as glute bridge, unilateral glute bridge, clamshell, pelvic drop and lunge. Each of the participants was examined three times-before taping, immediately after and 48 h after taping.

RESULTS

Before taping, the greatest GMed activation on the dominant side was noted in clamshell (54.12 %MVIC), whereas the lowest GMed activation was observed in glute bridge (36.35 %MVIC). The comparison of results obtained before and immediately after taping in all the groups revealed a statistically significant increase in GMed activation (p < 0.05), while the comparison of results achieved before and 48 h after taping showed significant differences in glute bridge in groups KT and RT. In all the groups, the differences in results obtained in the other exercises were not significant. Taking into account each of the applied exercises, at none of the three stages of examination were the differences between the groups significant.

CONCLUSIONS

Regardless of the type of taping applied (KT, RT, C), a significant increase in GMed activation was noted in all the exercises immediately after taping. At none of the stages of examination were the differences between the groups significant.

Effect of Ultrasound-Guided Percutaneous Neuromodulation of Sciatic Nerve on Hip Muscle Strength in Chronic Low Back Pain Sufferers: A Pilot Study

Background: Limited hip internal rotation range of motion (IR-ROM) and hip abductor weakness are recognized in low back pain (LBP) sufferers. The main aim was to investigate the effect of a ultrasound (US)-guided percutaneous neuromodulation (PNM) technique on hip strength in people with LBP. A second purpose was to discover whether the location along the sciatic nerve, where percutaneous neuromodulation was applied, could influence the change of strength response in these patients. Methods: Sixty LBP sufferers were recruited and divided randomly into three groups. All participants received an isolated percutaneous electrical stimulation at one of three different locations of the sciatic nerve pathway (proximal, middle, and distal), depending on the assigned group. Pain intensity, hip passive IR-ROM, hip muscle strength, and the Oswestry disability index (ODI) were analyzed. All variables were calculated before the intervention and one week after the intervention. Results: All interventions significantly decreased pain intensity and improved the IR-ROMs, strength, and functionality after one week (p = 0.001). However, between-group (treatment x time) differences were reported for flexion strength in the non-intervention limb (p = 0.029) and ODI (p = 0.021), although the effect size was small (Eta² = 0.1) in both cases. Conclusions: The application of an isolated intervention of the US-guided PNM technique may be a useful therapeutic tool to increase the hip muscle strength in patients with chronic LBP.

Effect of side-sling plank exercise on trunk and hip muscle activation in subjects with gluteus medius weakness

BACKGROUND

The effectiveness of side-sling plank (SSP) exercises on trunk and hip muscle activation in subjects with gluteus medius (Gmed) weakness is unclear.

OBJECTIVE

To quantify muscle activation of the rectus abdominis (RA), external oblique (EO), erector spinae (ES), lumbar multifidus (LM), Gmed, gluteus maximus (Gmax), and tensor fasciae latae (TFL) during SSP with three different hip rotations compared to side-lying hip abduction (SHA) exercise in subjects with Gmed weakness.

METHODS

Twenty-two subjects with Gmed weakness were recruited. SHA and three types of SSP exercises were performed: SSP with neutral hip (SSP-N), hip lateral rotation (SSP-L), and hip medial rotation (SSP-M). Surface electromyography was used to measure the activation of the trunk and hip muscles.

RESULTS

The trunk and hip muscles activations were generally significantly higher level during three SSP than SHA. SSP-M showed significantly lower EO activation while significantly higher ES and LM activation than SSP-L. Gmed activation was significantly higher during SSP-M than during SSP-L. TFL activation was significantly lower during SSP-M than during SSP-N and SSP-L.

CONCLUSIONS

SSP could be prescribed for patients who have reduced Gmed strength after injuries. Especially, SSP-M could be applied for patients who have Gmed weakness with dominant TFL.

Effect of gluteal muscle strengthening exercise on sagittal balance and muscle volume in adult spinal deformity following long-segment fixation surgery

This study aimed to investigate the changes in gluteal muscle volume and the effects of such changes in spinal alignment as a result of postoperative gluteal muscle strengthening exercise (GMSE) in patients following long-segment fixation for adult spinal deformity (ASD). Eighty-three consecutive patients (average age, 70.1 years) were analyzed. Three-dimensional CT scans were conducted to obtain serial axial gluteus muscle image slices. The size of each muscle area in every image slice was measured by Computer Aided Design and the sum of each muscle area was calculated. At the last follow-up, the sagittal vertical axis was significantly greater in the basic postoperative exercise group (1.49 mm vs. 17.94 mm), and the percentage of optimal sagittal alignment was significantly higher in the GMSE group (97.8% vs. 84.2%). At the last follow-up, the gluteus maximus volume was significantly higher in the GMSE group (900,107.1 cm³ vs. 825,714.2 cm³, p = 0.036). For the increase in muscle volume after 1 year, gluteus maximus and medius volumes showed a significant intergroup difference (+ 6.8% vs. + 2.4% and + 6.9% vs. + 3.6%). The GMSE protocol developed in this study could effectively increase gluteal muscle volume and maintain the optimal sagittal balance in patients with ASD.

Best Practices for Postoperative Management of Posterior Sacroiliac Joint Fusion

Sacroiliac joint (SIJ) pain is a common cause of low back pain. Traditionally, treatment for SIJ joint pain and dysfunction has consisted of physical therapy, medication management, SIJ injections, and SIJ ablations. Improved recognition of the SIJ as an etiology for back pain has led to advances in treatment options. Radiofrequency of the lateral sacral branches has been shown to be effective, though evidence is fraught with inconsistent patient selection, study design and procedural technique. It also does not directly address the mechanical dysfunction of the SIJ. In order to create a more enduring approach SIJ fusion has become an attractive option to reduce pain and to improve function. This method of SI joint treatment requires guidance in the perioperative phase of care from both the physicians and advanced practice providers (APP). In order to improve care and outcomes of those undergoing posterior SI joint fusion the American Society of Pain and Neuroscience appointed an expert panel of physicians and advanced practice providers to create a best practice for the post operative care of this approach. As with any best practice, the panel considered current peer reviewed literature and clinical expertise to create guidance today. This is intended to be a living document with modifications as additional evidence comes to light in data publication. The goals of this paper are to focus on (1) wound care, (2) medication use, (3) physical activity and (4) therapeutic exercises.

Feasibility of Superimposed Neuromuscular Electrical Stimulation to the Gluteus Medius During a Resistance Training Program

CONTEXT

Gluteus medius (GMed) weakness is a common impairment seen across multiple lower-extremity pathologies. Greater GMed weakness is moderately associated with greater frontal plane motion, often termed dynamic knee valgus during functional tasks which may increase risk of lower-extremity injury. Neuromuscular electrical stimulation (NMES) superimposed to targeted muscles has emerged in clinical practice; however, NMES superimposed to the GMed in unknown. It is essential to assess the safety, credibility, and expectancy of NMES superimposed to the GMed prior to implementation in clinical practice. The objective of this study was to evaluate feasibility, safety, credibility, and expectancy of improvement with a 2-week intervention with or without NMES to the GMed in females with dynamic knee valgus.

DESIGN

Feasibility study.

METHODS

A total of 22 adult females with dynamic knee valgus (age = 21.8 [1.4] y, mass = 76.9 [18.8] kg, height = 1.7 [0.1] m) completed a 2-week intervention with NMES or a sham treatment superimposed to the GMed during all therapeutic exercises. Feasibility was assessed by recruitment and completion rate, while safety was assessed by the total number of adverse events. Treatment credibility and expectancy was assessed with the Credibility Expectancy Questionnaire. Mixed-measure analysis of variance were used for statistical analysis (P ≤ .05).

RESULTS

Recruitment was completed in 5 months with 100% completion rate and no adverse events. There was no difference in treatment credibility between groups (NMES = 23.7 [2.3], sham = 21.7 [3.4], P = .12); however, the NMES group demonstrated a greater expectancy score (NMES = 20.0 [3.8], sham = 15.9 [5.1], P = .045).

CONCLUSION

Resistance training with NMES superimposed to the GMed is a feasible and safe intervention that resulted in greater expectance of success. Clinicians may consider superimposing NMES to the gluteal muscles when addressing muscle weakness in individuals with dynamic knee valgus.

When Treating Coexisting Low Back Pain and Hip Impairments, Focus on the Back: Adding Specific Hip Treatment Does Not Yield Additional Benefits-A Randomized Controlled Trial

OBJECTIVE

To determine whether adding hip treatment to usual care for low back pain (LBP) improved disability and pain in individuals with LBP and a concurrent hip impairment.

DESIGN

Randomized controlled trial.

METHODS

Seventy-six participants (age, 18 years or older; Oswestry Disability Index, 20% or greater; numeric pain-rating scale, 2 or more points) with LBP and a concurrent hip impairment were randomly assigned to a group that received treatment to the lumbar spine only (LBO group) (n = 39) or to one that received both lumbar spine and hip treatments (LBH group) (n = 37). The individual treating clinicians decided which specific low back treatments to administer to the LBO group. Treatments aimed at the hip (LBH group) included manual therapy, exercise, and education, selected by the therapist from a predetermined set of treatments. Primary outcomes were disability and pain, measured by the Oswestry Disability Index and the numeric pain-rating scale, respectively, at baseline, 2 weeks, discharge, 6 months, and 12 months. The secondary outcomes were fear-avoidance beliefs (work and physical activity subscales of the Fear-Avoidance Beliefs Questionnaire), global rating of change, the Patient Acceptable Symptom State, and physical activity level. We used mixed-model 2-by-3 analyses of variance to examine group-by-time interaction effects (intention-to-treat analysis).

RESULTS

Data were available for 68 patients at discharge (LBH group, n = 33; LBO group, n = 35) and 48 at 12 months (n = 24 for both groups). There were no between-group differences in disability at discharge (-5.0; 95% confidence interval [CI]: -10.9, 0.89; P = .09), 12 months (-1.0; 95% CI: -4.44, 2.35; P = .54), and all other time points. There were no between-group differences in pain at discharge (-0.2; 95% CI: -1.03, 0.53; P = .53), 12 months (0.1; 95% CI: -0.53, 0.72; P = .76), and all other time points. There were no between-group differences in secondary outcomes, except for higher Fear-Avoidance Beliefs Questionnaire (work subscale) scores in the LBH group at 2 weeks (-3.35; 95% CI: -6.58, -0.11; P = .04) and discharge (-3.45; 95% CI: - 6.30, -0.61; P = .02).

CONCLUSION

Adding treatments aimed at the hip to usual low back physical therapy did not provide additional short- or long-term benefits in reducing disability and pain in individuals with LBP and a concurrent hip impairment. Clinicians may not need to include hip treatments to achieve reductions in low back disability and pain in individuals with LBP and a concurrent hip impairment. J Orthop Sports Phys Ther 2021;51(12):581-601. Epub 16 Nov 2021. 2021. doi:10.2519/jospt.2021.10593.

Is it appropriate to use external loads during side-lying hip abduction exercise for weakened gluteus medius?

BACKGROUND

Side-lying hip abduction exercise could be beneficial to improve the neuromuscular control of the hip abductor; however, there has been limited information available to determine the exercise load during the exercise.

OBJECTIVE

This study aimed to demonstrate the effects of using external loads on the hip abductor muscles during side-lying hip abduction exercises in females with gluteus medius (GM) weakness.

METHODS

This study enrolled 24 females with weakness in the GM. Electromyographic (EMG) data of the quadratus lumborum (QL) and GM muscles were recorded during the exercise under three load conditions: no-load, external load-1 (3% of body weight), and external load-2 (5% of body weight).

RESULTS

During the exercise, the EMG activities of the QL were significantly different under all three conditions (p< 0.05), with greater activity observed in the external load-2 condition (92.05 ± 65.93% maximal voluntary isometric contraction [MVIC]) as compared to the others, and in the external load-1 condition (82.47 ± 57.36% MVIC) as compared to the no-load condition (48.94 ± 45.09% MVIC). Furthermore, the GM/QL ratios showed significant differences between no-load (1.78 ± 1.47) and external load-1 conditions (0.93 ± 0.60), and between no-load and external load-2 (0.85 ± 0.45) conditions (p< 0.05).

CONCLUSION

These findings suggest that greater load could be a factor to increase the QL activity during the exercise in females with weakened GM.

Adding muscle power exercises to a strength training program for people with patellofemoral pain: protocol of a randomized controlled trial

Background

Strong evidence supports the proximal combined with quadriceps strengthening for patellofemoral pain (PFP) rehabilitation. However, most reported rehabilitation programs do not follow specific exercise prescription recommendations or do not provide adequate details for replication in clinical practice. Furthermore, people with PFP have power deficits in hip and knee muscles and it remains unknown whether the addition of power exercises would result in superior or more consistent outcomes. Therefore, this study is designed to verify whether the benefits of a rehabilitation program addressing proximal and knee muscles comprising power and strength exercises are greater than those of a program consisting of strength exercises only.

Method

This study will be a randomized controlled trial that will be conducted at university facilities. A minimum of 74 people with PFP between the ages of 18 and 45 years will be included. The experimental group will engage in a 12-week resistance training program focusing on proximal and knee muscles using power and strength exercises. The control group will engage in a 12-week resistance training program focusing on proximal and knee muscles using strength exercises only. Primary outcomes will be pain intensity and physical function; and secondary outcomes will be kinesiophobia, self-reported improvement, quality of life, peak hip and knee torque, and hip and knee rate of force development. The primary outcomes will be evaluated at baseline, and after 6 weeks, 12 weeks, 3 months, 6 months, and 1 year. The secondary outcomes will be evaluated at baseline and immediately after the interventions. Therapists and participants will not be blinded to group allocation.

Discussion

This randomized clinical trial will investigate if adding power exercises to a progressive resistance training may lead to more consistent outcomes for PFP rehabilitation. The study will provide additional knowledge to support rehabilitation programs for people with PFP.

Trial registration

ClinicalTrials.gov NCT 03985254. Registered on 26 August 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05748-x.

Gluteal muscle activation during rehabilitation exercises in female field hockey players

BACKGROUND

Field hockey, a team sport played by both men and women at both recreational and professional levels, requires maintaining a forward flexed posture putting stress on the lumbar spine. Hence, it is necessary to assess the muscles supporting the lumbar spine, especially those surrounding the hip, to inform strengthening exercises for this population.

OBJECTIVES

To establish the best body weight rehabilitation exercises shown to produce high muscle activation (≥ 61%MVIC - maximal voluntary isometric contraction) for both the gluteus maximus (Gmax) and medius (Gmed) muscles. Four exercises fell into this category.

METHOD

Surface electromyography (sEMG) was used to record the muscle activation of Gmax and Gmed of four body weight rehabilitation exercises in 26 high-performance female field hockey players. The %MVIC activation data of both Gmax and Gmed were analysed using a three-way ANOVA.

RESULTS

The single-leg squat generated the highest %MVIC activation of both Gmax (125.65%MVIC) and Gmed (126.30%MVIC). The only statistically significant difference for Gmax was between the single-leg squat and plank with hip extension (p = 0.0487). No statistically significant difference was observed for Gmed between the four body weight rehabilitation exercises (p = 0.6285).

CONCLUSION

The four exercises generated similar %MVIC activation levels. The single-leg squat produced the highest observed %MVIC of Gmax and Gmed in high-performance female field hockey players and is, therefore, recommended.

CLINICAL IMPLICATIONS

Implementation of the findings could result in benefits during prehabilitation, injury prevention programmes and the later stages of rehabilitation for high-performance female field hockey players.

The Neuromuscular Effects of the Copenhagen Adductor Exercise: A Systematic Review

BACKGROUND

Groin strains are one of the most common time-loss injuries in athletes. The Copenhagen Adductor Exercise (CAE) eccentrically strengthens the adductors and may function to prevent adductor strains, similar to the eccentric mechanism in which the Nordic Hamstrings exercise acts to prevent hamstring strains.

OBJECTIVE

The purpose of this study was to systematically review the literature on the CAE and its effects on adductor muscle strength and muscle activity in athletes.

STUDY DESIGN

Systematic Review.

METHODS

A systematic search of the literature was performed in the following databases: Pubmed; Medline (EBSCO); Sportdiscus; Scopus; Web of Science; CINAHL; Proquest; Cochrane Library; Physiotherapy Evidence Database (PEDro). Inclusion criteria consisted of 1) implements CAE, 2) includes athletes of any age participating in at least one sport, 3) study type is a cohort study or randomized control trial. Studies were excluded if they were not written in English or did not measure strength as an outcome. Data were extracted on eccentric hip adductor strength (EHAD), eccentric hip abductor strength (EHAB), EHAD:EHAB ratio, and electromyography (EMG) activity of the adductor muscles. Quality assessment was performed on all included studies using Quality Assessment Tool for Quantitative Studies.

RESULTS

Five articles were identified for inclusion, four of which received a strong rating, and one a moderate rating on the Quality Assessment Tool for Quantitative Studies. The CAE significantly increased EHAD in four of the four studies that examined it; significantly increased EHAB and EHAD:EHAB in three of the three studies that examined them, and increased the EMG activity of the adductors in the dominant leg 108%.

CONCLUSION

Overall, the CAE increases EHAD, EHAB, EHAD:EHAB, and EMG activity in the hip adductors in male soccer players. The increase in strength may reduce adductor muscle injuries, although more research needs to be done in this area to identify a clear relationship between the CAE and groin injury prevention.

LEVEL OF EVIDENCE

1b.

Flexible Electrodes for In Vivo and In Vitro Electrophysiological Signal Recording

A variety of electrophysiological signals (electrocardiography, electromyography, electroencephalography, etc.) are generated during the physiological activities of human bodies, which can be collected by electrodes and thus provide critical insights into health status or facilitate fundamental scientific research. The long-term stable and high-quality recording of electrophysiological signals is the premise for their further applications, leading to demands for flexible electrodes with similar mechanical modulus and minimized irritation to human bodies. This review summarizes the latest advances in flexible electrodes for the acquisition of various electrophysiological signals. First, the concept of electrophysiological signals and the characteristics of different subcategory signals are introduced. Second, the invasive and noninvasive methods are reviewed for electrophysiological signal recording with a highlight on the design of flexible electrodes, followed by a discussion on their material selection. Subsequently, the applications of the electrophysiological signal acquisition in pathological diagnosis and restoration of body functions are discussed, showing the advantages of flexible electrodes. Finally, the main challenges and opportunities in this field are discussed. It is believed that the further exploration of materials for flexible electrodes and the combination of multidisciplinary technologies will boost the applications of flexible electrodes for medical diagnosis and human-machine interface.

Effects of Log-Rolling Position on Hip-Abductor Muscle Activation During Side-Lying Hip-Abduction Exercise in Participants With Gluteus Medius Weakness

CONTEXT

Weakness of the gluteus medius and gluteus maximus is associated with a variety of musculoskeletal disorders. However, activation of synergistic muscles that are not targeted should be considered when prescribing side-lying hip-abduction (SHA) exercises. Log-rolling positions may affect hip-abductor activity during SHA.

OBJECTIVE

To determine the effects of log-rolling positions on gluteus medius, gluteus maximus, and tensor fasciae latae activity during SHA in participants with gluteus medius weakness.

DESIGN

Controlled laboratory study.

SETTING

University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty-one participants with gluteus medius weakness.

INTERVENTION(S)

Three types of SHA were performed: frontal-plane SHA in neutral position (SHA-neutral), frontal-plane SHA in anterior log-rolling position (SHA-anterior rolling), and frontal-plane SHA in posterior log-rolling position (SHA-posterior rolling).

MAIN OUTCOME MEASURE(S)

Surface electromyography was used to measure hip-abductor activity. One-way repeated-measures analysis of variance was calculated to assess the statistical significance of the muscle activity.

RESULTS

The SHA-anterior rolling showed greater gluteus medius and gluteus maximus activation than the SHA-neutral (P = .003 and P < .001, respectively) and SHA-posterior rolling (P < .001 and P < .001, respectively). The SHA-neutral demonstrated greater gluteus medius and gluteus maximus activation than the SHA-posterior rolling (P < .001 and P = .001, respectively). The SHA-anterior rolling produced less tensor fasciae latae activation than the SHA-neutral (P < .001) and SHA-posterior rolling (P < .001). The SHA-neutral showed less tensor fasciae latae activation than the SHA-posterior rolling (P < .001).

CONCLUSIONS

The SHA-anterior rolling may be an effective exercise for increasing activation of the gluteus medius and gluteus maximus while decreasing activation of the tensor fasciae latae in participants with gluteus medius weakness.

Lower Extremity Nerve Transfers in Acute Flaccid Myelitis Patients: A Case Series

Acute flaccid myelitis (AFM) is characterized by flaccid paralysis following prodromal symptoms. Complete recovery is rare, and patients typically have residual extremity weakness. This study aimed to describe the technique and outcomes of lower extremity nerve transfers for children with AFM.

Autoregulation in Resistance Training for Lower Limb Tendinopathy: A Potential Method for Addressing Individual Factors, Intervention Issues, and Inadequate Outcomes

Musculoskeletal disorders, such as tendinopathy, are placing an increasing burden on society and health systems. Tendinopathy accounts for up to 30% of musculoskeletal disorders, with a high incidence in athletes and the general population. Although resistance training has shown short-term effectiveness in the treatment of lower limb tendinopathy, more comprehensive exercise protocols and progression methods are required due to poor long-term outcomes. The most common resistance training protocols are predetermined and standardized, which presents significant limitations. Current standardized protocols do not adhere to scientific resistance training principles, consider individual factors, or take the importance of individualized training into account. Resistance training programs in case of tendinopathy are currently not achieving the required intensity and dosage, leading to high recurrence rates. Therefore, better methods for individualizing and progressing resistance training are required to improve outcomes. One potential method is autoregulation, which allows individuals to progress training at their own rate, taking individual factors into account. Despite the finding of their effectiveness in increasing the strength of healthy athletes, autoregulation methods have not been investigated in case of tendinopathy. The purpose of this narrative review was 3-fold: firstly, to give an overview and a critical analysis of the individual factors involved in tendinopathy and current resistance training protocols and their limitations. Secondly, to give an overview of the history, methods, and application of autoregulation strategies both in sports performance and physiotherapy. Finally, a theoretical adaptation of a current tendinopathy resistance training protocol using autoregulation methods is presented, providing an example of how the method could be implemented in clinical practice or future research.

Biceps Femoris Activation during Hamstring Strength Exercises: A Systematic Review

BACKGROUND

The aim of the study was to systematically evaluate the biceps femoris long head activation across cross-sectional hamstring strength exercise studies.

METHODS

A systematic review design was followed. The search strategy conducted in PubMed, Cochrane Library, and Web of Sciences databases found a total of 3643 studies. Once inclusion and exclusion criteria were applied, 29 studies were finally included in this systematic review. A total of 507 participants and 114 different exercises were analyzed. Exercises were evaluated individually and grouped into several categories: Nordics, isokinetic exercises, lunges, squats, deadlifts, good mornings, hip thrusts, bridges, leg curls, swings, hip and back extensions, and others.

RESULTS

Results showed the isokinetic and Nordic exercises as the categories with highest biceps femoris activation (>60% of Maximal Voluntary Isometric Contraction). Nordic hamstring exercise ankle dorsiflexion was the exercise that achieved the highest biceps femoris long head activation (128.1% of its Maximal Voluntary Isometric Contraction).

CONCLUSIONS

The results from this systematic review suggest that isokinetic and Nordic exercises seem to be the best option to activate biceps femoris long head. Future studies evaluating the implementation of these exercises in prevention programs are needed.

How effective is an evidence-based exercise intervention in individuals with patellofemoral pain?

OBJECTIVES

Guidelines for a comprehensive rehabilitation programme for patellofemoral pain (PFP) have been developed by international experts. The aim of this study was to analyse the effect of such a rehabilitative exercise programme on pain, function, kinesiophobia, running biomechanics, quadriceps strength and quadriceps muscle inhibition in individuals with PFP.

DESIGN

Observational study.

SETTING

Clinical environment.

PARTICIPANTS

Twenty-seven participants with PFP.

MAIN OUTCOME MEASURES

Symptoms [numeric pain rating scale (NPRS)and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS)], function measured by using the KUJALA scale and KOOS, kinesiophobia measured by using the Tampa scale, three-dimensional biomechanical running data, quadriceps isometric, concentric and eccentric strength and arthrogenic muscle inhibition (AMI) were acquired before and after the six-week exercise programme.

RESULTS

Although pain did not significantly improve all patients were pain-free after the six-week exercise programme (NPRS: p = 0.074). Function, kinesiophobia and quadriceps AMI improved significantly after the six-week exercise programme (KUJALA: p = 0.001, KOOS: p = 0.0001, Tampa: p = 0.017, AMI: p = 0.018). Running biomechanics during stance phase did not change after the exercise intervention. Quadriceps strength was not different after the six-week exercise programme (isometric: p = 0.992, concentric: p = 0.075, eccentric: p = 0.351).

CONCLUSION

The results of this study demonstrate that the current exercise recommendations can improve function and kinesiophobia and reduce pain and AMI in individuals with PFP. There is a need for reconsideration of the current exercise guidelines in stronger individuals with PFP.

Hip and Core Muscle Activation During High-Load Core Stabilization Exercises

BACKGROUND

There is some evidence that high-load lumbar stabilization exercises, such as back bridge, can recruit both local and global muscles.

HYPOTHESIS

Therapeutic exercises would optimize gluteus maximus (GMax), gluteus medius (GMed), multifidus (MF), and transversus abdominis (TrA) activation, while minimizing the activation of the tensor fascia latae (TFL) and erector spinae (ES) muscles in healthy individuals.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

LEVEL OF EVIDENCE

Level 4.

METHODS

In this cross-sectional study, surface electromyography (EMG) of GMax, GMed, TFL, TrA, MF, and ES was used to quantify the gluteal-to-TFL muscle activation (GTA) index and a ratio of local to global (L/G) lumbar muscles during (1) the elbow-toe exercise in the prone position, (2) the elbow-toe with right left lifted, (3) the hand-knee with left arm and right leg lifted, (4) the back bridge, (5) the back bridge with right leg lifted, (6) the back bridge with left leg lifted, (7) the side bridge with left leg lifted, (8) the side bridge with right leg lifted, and (9) the elbow-toe with right leg horizontally lifted exercises in healthy individuals (20 men, 20 women; age, 25 ± 4 years).

RESULTS

The back bridge exercise with left leg lift generated the highest L/G muscles activity ratio (L/G = 3.35) while the hand-knee exercise yielded the lowest L/G muscles activity ratio (L/G = 1.21). The side bridge exercise with left elbow and foot and lifting the right leg (GTA = 63.78), hand-knee exercise (GTA = 49.62), back bridge (GTA = 28.05), and elbow-toe exercise with left leg horizontally lifted (GTA = 23.02) generated the highest GTA indices, respectively. Meanwhile, the normalized EMG amplitude for GMax was significantly less than the TFL, for elbow-toe exercise (P < 0.001), back bridge with left leg lift (P = 0.001), side bridge exercise with the right elbow and foot and lifting the left leg (P = 0.002), and elbow-toe exercise with right leg horizontally lifted (P < 0.001).

CONCLUSION

The highest GTA indexes were observed during (1) the side bridge lifting the dominant leg and (2) the hand-knee horizontally lifting dominant leg, respectively. The L/G ratio was highest during (1) the back bridge lifting nondominant leg, (2) back bridge, and (3) back bridge lifting dominant leg, respectively. This study supports the use of back bridge exercises to strengthen the MF and side bridges to improve gluteal muscle activation.

CLINICAL RELEVANCE

The highest GTA index was observed in the side bridge lifting the right leg. Highest L/G ratio was in the back bridge with nondominant leg lifted. This study supports the use of back bridge exercises to strengthen the MF. This study supports the use of side bridges to improve gluteal muscle activation.

Hip and Trunk Muscle Activity and Mechanics During Walking With and Without Unilateral Weight

Pelvic drop is caused by decreased hip abductor muscle activity and is associated with lower-extremity injury. Hip abductor strengthening exercises are well established; however, no standard method exists to increase hip abductor activity during functional activities. The purpose of this research was to study the effects of walking with a unilateral weight. A total of 26 healthy adults walked on an instrumented treadmill with and without handheld weight (15%-20% body weight). Muscle activity, kinematic, and kinetic data were collected using surface electromyography, motion capture, and force plates, respectively. Average hip and trunk muscle activity, hip, pelvic, and trunk angles, and peak internal hip moments during stance were compared for each side (contralateral/ipsilateral to the weight) between conditions (unweighted/weighted) using a generalized linear model with generalized estimating equation correction. Interactions between condition and side were observed for muscle activity, frontal plane pelvic and trunk angles, and frontal plane hip moments (P ≤ .003). Compared with the unweighted condition, the weighted condition had higher hip abductor activity contralateral to the weight (P < .001), while no change was found ipsilateral to the weight (P ≥ .790). Similar changes were found for kinematic and kinetic variables. Walking with a unilateral weight may be a therapeutic option to increase functional hip abductor activity.

Activation of the gluteus maximus, gluteus medius and tensor fascia lata muscles during hip internal and external rotation exercises at three hip flexion postures

BACKGROUND

Hip internal and external rotation exercises are usually performed in clinical practice. However, given the synergies required to stabilize the hip in the frontal plane, it is not clear how the activation of target muscles will differ between the two exercise directions.

OBJECTIVE

I) Compare the activation of the upper and lower fibers of gluteus maximus (GMax), gluteus medius (GMed) and tensor fascia lata muscles between the hip internal and external rotation exercises; ii) Compare the maximal isometric force between hip internal and external rotation exercises and; iii) Assess the effect of varying hip flexion angles on muscle activation and maximal isometric force.

STUDY DESIGN

A cross sectional study.

METHODS

Electromyography and force production of twenty-one participants were measured during maximum isometric hip internal and external rotation in three postures: 0°, 45° and 90° of hip flexion.

RESULTS

MANOVA results showed a larger activation of the GMed, tensor fascia lata and upper GMax (p < .001) for hip internal rotation compared to external rotation regardless of hip flexion angle. For the lower GMax, the same was observed when the hip was kept at 90° of flexion. Maximal isometric force during hip external rotation was greater than during hip internal rotation at 0° posture, and lower at 90° posture (p < .001).

CONCLUSION

The gluteus and the tensor fascia lata muscles were substantially recruited during the hip internal rotation exercise, and barely recruited during the hip external rotation exercise. Hip flexion influences the myoeletric activity and isometric force production during the internal rotation exercise.

Impact of Three Strengthening Exercises on Dynamic Knee Valgus and Balance with Poor Knee Control among Young Football Players: A Randomized Controlled Trial

The observed dynamic knee valgus and the limited dynamic balance described in the literature are modifiable risk factors for injuries in athletes. Therefore, identification and appropriate prevention are crucial in managing the development of young athletes. The aim of the study was to assess the effectiveness of three exercises strengthening the muscles: gluteal medius, popliteal and tibialis posterior to reduce dynamic knee valgus and improve the dynamic balance of the lower limbs in young football players with poor knee control. A total of 134 footballers were assessed for eligibility, and finally 45 participants (age 12–15) met the inclusion criteria. Participants were assessed with 2D video kinematic analysis during single-leg squats to assess the knee valgus angles and the dynamic balance (Y-Balance Test). No significant interactions between groups (Control and Exercise) and time (baseline and after 6 week) were noted for dynamic valgus for the left and right knee (p > 0.05). For the dynamic balance, there were statistically significant results, but not clinically relevant for anterior, posteromedial, and composite direction for the right lower limbs and for the anterior direction for left lower limbs in the exercise group. However, there were no significant differences (p > 0.05) in all of the YBT scores for both lower limbs between groups. This study demonstrated that there were no statistically significant differences in dynamic knee valgus angles and dynamic balance values after 6 weeks of exercise program in young footballers with poor knee control. Future randomized trials should focus on more comprehensive exercises, where possible using biofeedback methods to improve knee kinematics.

The effect of chronic ankle instability on muscle activations in lower extremities

BACKGROUND/PURPOSE

Muscular reflex responses of the lower extremities to sudden gait disturbances are related to postural stability and injury risk. Chronic ankle instability (CAI) has shown to affect activities related to the distal leg muscles while walking. Its effects on proximal muscle activities of the leg, both for the injured- (IN) and uninjured-side (NON), remain unclear. Therefore, the aim was to compare the difference of the motor control strategy in ipsilateral and contralateral proximal joints while unperturbed walking and perturbed walking between individuals with CAI and matched controls.

MATERIALS AND METHODS

In a cross-sectional study, 13 participants with unilateral CAI and 13 controls (CON) walked on a split-belt treadmill with and without random left- and right-sided perturbations. EMG amplitudes of muscles at lower extremities were analyzed 200 ms after perturbations, 200 ms before, and 100 ms after (Post100) heel contact while walking. Onset latencies were analyzed at heel contacts and after perturbations. Statistical significance was set at alpha≤0.05 and 95% confidence intervals were applied to determine group differences. Cohen's d effect sizes were calculated to evaluate the extent of differences.

RESULTS

Participants with CAI showed increased EMG amplitudes for NON-rectus abdominus at Post100 and shorter latencies for IN-gluteus maximus after heel contact compared to CON (p<0.05). Overall, leg muscles (rectus femoris, biceps femoris, and gluteus medius) activated earlier and less bilaterally (d = 0.30-0.88) and trunk muscles (bilateral rectus abdominus and NON-erector spinae) activated earlier and more for the CAI group than CON group (d = 0.33-1.09).

CONCLUSION

Unilateral CAI alters the pattern of the motor control strategy around proximal joints bilaterally. Neuromuscular training for the muscles, which alters motor control strategy because of CAI, could be taken into consideration when planning rehabilitation for CAI.

Change in Regional Activity of the Quadratus Lumborum During Bridge Exercises

Context: The quadratus lumborum (QL) is expected to contribute to segmental motor control of the lumbar spine to prevent low back pain. It has different layers (anterior [QL-a] and posterior [QL-p] layers), whose functional differences are becoming apparent. However, the difference between the QL-a and QL-p activities during bridge exercises utilized in rehabilitation is unclear. Objective: To compare QL-a and QL-p activities during bridge exercises. Design: Repeated-measurement design was used to assess electromyographic activity of trunk muscles recorded during 14 types of bridge exercises. Setting: University laboratory. Participants: A total of 13 healthy men with no history of lumbar spine disorders participated. Intervention: The participants performed 14 types of bridge exercises (3, 3, and 8 types of side bridge, back bridge, and front bridge [FB], respectively). Main Outcome Measures: Fine-wire electromyography was used for QL-a and QL-p activity measurements during bridge exercises. Results: Both QL-a and QL-p showed the highest activity during the side bridge with hip abduction  (47.3% [29.5%] and 43.0% [32.9%] maximal voluntary isometric contraction, respectively). The activity of the QL-a was significantly higher than that of the QL-p during back bridge with ipsilateral leg lift and FB elbow–toe with ipsilateral arm and contralateral leg lift (P < .05). With regard to the QL-p, the activity of the FB hand–knee with contralateral arm and ipsilateral leg lift, the FB elbow–knee with contralateral arm and ipsilateral leg lift, and the FB elbow–toe with contralateral arm and ipsilateral leg lift were significantly higher than that of the FB elbow–knee and FB elbow–toe (P < .05). Conclusion: This study indicates different regional activities; the QL-a activated during the back bridge with ipsilateral leg lift and FB with ipsilateral arm lift, and the QL-p activated during the FB with ipsilateral leg lift. These results have implications for the rehabilitation of low back pain or lumbar scoliosis patients based on QL recruitment.

Weight-Bearing Versus Traditional Strength Assessments of the Hip Musculature

CONTEXT

Traditional nonweight-bearing (NWB) hip-strength assessments may not directly translate to functional strength during weight-bearing (WB) activity. How NWB assessments of hip muscle strength compare with WB assessments in various positions is currently unknown.

OBJECTIVE

To determine the magnitude of the differences and correlations between NWB hip strength and WB functional strength during the squatting and lunge (LNG) positions in female athletes.

DESIGN

Crossover design.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Female athletes (N = 51, age = 16.2 ± 3.5 years, height = 161.5 ± 8.3 cm, mass = 58.3 ± 11.6 kg).

INTERVENTION(S)

Isometric resistance (N/kg) was determined for the dominant and nondominant limbs via WB assessments (squat-bilateral [legs tested simultaneously], squat-unilateral, and lunge positions) and NWB assessments (hip abduction [HAB], hip extension HEXT], and hip external rotation [HER]).

MAIN OUTCOME MEASURE(S)

To compare differences between positions (P ≤ .05), we used effect sizes (d) and matched-pairs t tests, and we calculated Pearson r and R2 values.

RESULTS

During the squat-bilateral on the dominant limb, females produced the most hip torque (6.13 ± 1.12 N/kg). The magnitudes of differences were very large compared with HER (3.96 ± 0.83, d = 2.2), HEXT (3.22 ± 0.69, d = 3.2), and HAB (3.80 ± 1.01, d = 2.2; all P values ≤ .01), and positions were moderately correlated (r = 0.347-0.419, R2 = 0.12-0.18). The lunge position produced the least amount of torque in the dominant limb (2.44 ± 0.48 N/kg) compared with HER (d = -2.3), HEXT (d = -1.3), and HAB (d = -1.7; all P values ≤ .001), and correlations were small to moderate (r = 0.236-0.310, R2 = 0.06-0.10).

CONCLUSIONS

Strength in WB positions was different than strength evaluated using traditional NWB assessments in female athletes. Weight-bearing tests may provide clinicians with additional information regarding strength and function.

Hip Muscle Strengthening for Knee Osteoarthritis: A Systematic Review of Literature

BACKGROUND AND PURPOSE

Osteoarthritis (OA) of the knee joint results in chronic pain and functional decline among older adults. Hip muscle weakness has been observed in persons with knee OA and is claimed to increase the medial compartment loading on the knee joint. Although individual studies are available, no review has yet integrated the literature on the benefits of hip muscle strengthening for persons with knee OA. This review aims to systematically summarize the current evidence on the effectiveness of hip muscle strengthening on knee pain, lower extremity function, and biomechanical measures of the knee in persons with knee OA.

METHODS

An extensive electronic literature search was conducted in the databases PubMed, Scopus, Cumulative Index to Nursing and Allied Health (CINAHL), Cochrane Central Register of Controlled Trials (CENTRAL), and Physiotherapy Evidence Database (PEDro) to identify the published trials in the English language from January 1990 to August 2017. Randomized controlled trials that studied the effectiveness of hip muscle strengthening in persons with knee OA on knee pain, physical function, and biomechanical measures of the knee were considered for inclusion. The key word combinations were knee osteoarthritis, degenerative arthritis, arthralgia, muscle strengthening, and resistance training using the Boolean operators AND, OR. Two reviewers independently performed the study selection, and a third reviewer intervened when the consensus was not attained. Quality assessment of the included studies was carried out using the PEDro scale.

RESULTS AND DISCUSSION

The search produced 774 results, from which 81 full-text articles were studied. Five randomized controlled trials of good methodological quality, including 331 participants, were included in the review. The effectiveness of hip muscle strengthening was assessed in isolation, combination, and comparison with other lower extremity exercise. Overall, the studies reported clear benefits of hip muscle strengthening on knee pain, physical function, and hip muscle strength. However, hip muscle strengthening was ineffective in improving the biomechanical measures such as dynamic alignment and knee adduction (also known as valgus) moment.

CONCLUSION

The current review identified strong, high-quality evidence to recommend hip muscle strengthening in the conservative management of persons with knee OA. Further research is needed to establish the underlying mechanisms for the clinical benefits.

ELECTROMYOGRAPHIC ANALYSIS OF GLUTEAL RECRUITMENT: AN EXPLORATION OF ACTIVATION DURING JUMPING TASKS

Background

Inability to maintain proper alignment of the pelvis and femur due to gluteal muscle weakness has been associated with numerous lower extremity pathologies. Therefore, many lower extremity rehabilitation and injury prevention programs employ exercises that target gluteal muscle strength and activation. While information regarding muscle activation during exercises that are typically done in the beginning stages of rehabilitation is available, evidence regarding the gluteal muscle activity during more functional and advanced exercises used during later stages of rehabilitation is sparse.

Purpose

To explore the recruitment of the gluteal muscles during jumping tasks in healthy participants to determine which jumping exercise best elicits gluteal muscle activation.

Study Design

Prospective cohort design.

Methods

Eighteen healthy recreational athletes (23.5 ± 3.8 years, 8M/10F, 67.56 ± 3.2 inches, 66.73 ± 9.5 kg) completed three trials of four jumping tasks: hurdle jump, split jump, V2 lateral jump, and cross-over jump in random order. Surface EMG electrodes were placed on each participant's bilateral gluteus medius (GMed) and maximus (GMax) to measure muscle activity during the jumping tasks. Maximal voluntary isometric muscle contraction (MVIC) was established for each muscle group in order to express each jumping task as a percentage of MVIC and allow standardized comparison across participants. EMG data were analyzed for all jumps using a root-mean-square algorithm and smoothed with a 62.5 millisecond time reference. Rank ordering of muscle activation during jumping tasks was performed utilizing the peak percent MVIC recorded during each jumping task.

Results

Three of the jumping tasks produced greater than 70% MVIC of the GMed muscle. In rank order from highest EMG value to lowest, these jumping tasks were: crossover jump (103% MVIC), hurdle jump (93.2% MVIC), and V2 lateral jump (84.7% MVIC). Two of the exercises recruited GMax with values greater than 70% MVIC. In rank order from highest EMG value to lowest, these jumping tasks were: hurdle jump (76.8% MVIC) and split jump (73.1% MVIC). Only the hurdle jump produced greater than 70% MVIC for both GMed and GMax muscles.

Conclusions

The jumping task that resulted in greatest activation of the GMed was the crossover jump, while hurdle jump led to the greatest activation of the GMax. The high %MVIC for the GMed during the crossover jump may be attributed to lack of maximal effort or lack of motivation during performance of maximal contractions during the manual muscle testing. Alternatively, substantial co-contraction of core muscles during the crossover jumping task may have led to higher values.

Level of Evidence

2b Individual Cohort Study.

A SYSTEMATIC REVIEW AND META-ANALYSIS OF COMMON THERAPEUTIC EXERCISES THAT GENERATE HIGHEST MUSCLE ACTIVITY IN THE GLUTEUS MEDIUS AND GLUTEUS MINIMUS SEGMENTS

Background

The gluteus medius (GMed) and gluteus minimus (GMin) muscle segments demonstrate different responses to pathology and ageing, hence it is important in rehabilitation that prescribed therapeutic exercises can effectively target the individual segments with adequate exercise intensity for strengthening.

Purpose

The purpose of this systematic review was to evaluate whether common therapeutic exercises generate at least high ( > 40% maximum voluntary isometric contraction (MVIC)) electromyographic (EMG) activity in the GMed (anterior, middle and posterior) and GMin (anterior and posterior) segments.

Methods

Seven databases (MEDLINE, EMBASE, CINAHL, AusSPORT, PEDro, SPORTdiscus and Cochrane Library) were searched from inception to May 2018 for terms relating to gluteal muscle, exercise, and EMG. The search yielded 6918 records with 56 suitable for inclusion. Quality assessment, data extraction and data analysis were then undertaken with exercise data pooled into a meta-analysis where two or more studies were available for an exercise and muscle segment.

Results

For the GMed, different variations of the hip hitch/ pelvic drop exercise generated at least high activity in all segments. The dip test, and isometric standing hip abduction are other options to target the anterior GMed segment, while isometric standing hip abduction can be used for the posterior GMed segment. For the middle GMed segment, the single leg bridge; side-lying hip abduction with hip internal rotation; lateral step-up; standing hip abduction on stance or swing leg with added resistance; and resisted side-step were the best options for generating at least high activity. Standing isometric hip abduction and different variations of the hip hitch/ pelvic drop exercise generated at least high activity in all GMin segments, while side-lying hip abduction, the dip test, single leg bridge and single leg squat can also be used for targeting the posterior GMin segment.

Conclusion

The findings from this review provide the clinician with confidence in exercise prescription for targeting individual GMed and GMin segments for potential strengthening following injury or ageing.

Level of Evidence

Level 1.

What is known about the subject

Previous reviews on GMed exercises have been based on single electrode, surface EMG measures at middle GMed segment. It is not known whether these exercises effectively target the other segments of GMed or the GMin at a sufficient intensity for strengthening.

What this study adds to existing knowledge

This review provides the clinician with confidence in exercise prescription of common therapeutic exercises to effectively target individual GMed and GMin segments for potential strengthening.

Are there differences in muscular activation to maintain balance between individuals with chronic obstructive pulmonary disease and controls?

BACKGROUND

The mechanisms underlying impaired balance in chronic obstructive pulmonary disease (COPD) are poorly understood, which makes it difficult to choose the best therapeutic approaches. Therefore, this study aimed to investigate patterns of muscular activation to maintain balance and its determinants in this population.

METHODS

Thirty-three subjects with COPD and 33 controls were assessed by a force platform in four tasks: standing with eyes opened (FHEO) and closed (FHEC); standing on unstable surface (SUS) and one-legged stance (OLS). Electromyographic activity of lower limb, trunk and neck muscles was concomitantly recorded. To asses functional balance, Brief-balance evaluation systems and timed up & go (TUG) tests were applied. Lung function, exercise capacity and muscle force were also assessed.

RESULTS

Subjects with COPD presented worse balance and higher scalene activation than controls in OLS (mean difference 23.0 [95%CI 1.7-44.3] _%Δ μV_RMS; P = 0.034), besides presenting also higher activation of gluteus medius during FHEC task (mean difference 1.5 [95%CI 0.2-2.8] _%Δ μV_RMS; P = 0.023) and taking longer to complete the TUG (mean difference 0.6 [95%CI 0.1-1.2] seconds; P = 0.042). Exercise capacity and peripheral muscle force were determinants of functional balance (r² = 0.505), whereas age (OR = 1.24; 95%CI 1.02-1.52) and total lung capacity (OR = 2.42; 95%CI 1.05-5.56) were determinants of static balance.

CONCLUSION

Individuals with COPD have worse static and functional balance in comparison with controls, besides presenting higher activation of scalene and gluteus medius during static balance tasks. Exercise capacity and peripheral muscle force emerged as determinants of functional balance, whereas age and lung hyperinflation contributed to poor static balance.

Impact of the "Sling Shot" Supportive Device on Upper-Body Neuromuscular Activity during the Bench Press Exercise

The aim of this study was to compare the muscle activity between the sling shot assisted (SS) and control (CONT) flat barbell bench press for selected external loads of 70%, 85%, 100% one-repetition maximum (1RM). Ten resistance-trained men participated in the study (age = 22.2 ± 1.9 years, body mass = 88.7 ± 11.2 kg, body height = 179.5 ± 4.1, 1RM in the bench press = 127.25 ± 25.86 kg, and strength training experience = 6 ± 2.5 years). Evaluation of peak muscle activity of the dominant body side was carried out using surface electromyography (sEMG) recorded for the triceps brachii, pectoralis major, and anterior deltoid during each attempt. The three-way repeated measure ANOVA revealed statistically significant main interaction for condition x muscle group (p < 0.01; η2 = 0.569); load x muscle group (p < 0.01; η2 = 0.709); and condition x load (p < 0.01; η2 = 0.418). A main effect was also observed for condition (p < 0.01; η2 = 0.968); load (p < 0.01; η2 = 0.976); and muscle group (p < 0.01; η2 = 0.977). The post hoc analysis for the main effect of the condition indicated statistically significant decrease in %MVIC for the SS compared to CONT condition (74.9 vs. 88.9%MVIC; p < 0.01; ES = 0.39). The results of this study showed that using the SS significantly affects the muscle activity pattern of the flat bench press and results in its acute decrease in comparison to an equal load under CONT conditions. The SS device may be an effective tool both in rehabilitation and strength training protocols by increasing stability with a reduction of muscular activity of the prime movers.

An exploratory study investigating the effect of foot type and foot orthoses on gluteus medius muscle activity

Background

Abnormal gluteus medius muscle activity is associated with a number of musculoskeletal conditions. Research investigating the effect of foot type and foot orthoses on gluteus medius muscle activity is both conflicting and limited. The primary aim was to investigate the relationship between foot type and gluteus medius muscle activity during shod walking. The secondary aims of this study were to explore the effect and amount of usage of a pair of unmodified prefabricated foot orthoses on gluteus medius muscle activity during shod walking.

Methods

Foot type was determined using the foot posture index and gluteus medius muscle activity was measured with surface electromyography in 50 healthy adults during shod walking. Participants were then fitted with prefabricated foot orthoses and required to return after 4 weeks. Pearson’s correlation and one-way ANOVA were used to determine effect of foot type. Paired t-tests and ANCOVA were used to determine effect of foot orthoses.

Results

Participants with a cavus foot type demonstrated significantly more gluteus medius mean (p = 0.04) and peak amplitude (p = 0.01), and a greater range in amplitude (p = 0.01) compared to participants with a neutral foot type. Compared to a planus foot type, participants with a cavus foot type demonstrated significantly larger mean (p = 0.02) and peak amplitude (p = 0.01), and a greater range in amplitude (p = 0.01). Prefabricated foot orthoses did not change the gluteus medius muscle activity.

Conclusion

When assessing healthy adults with a cavus foot type, clinicians and researchers should be aware that these participants may display higher levels of gluteus medius muscle activity during gait compared to neutral and planus type feet. Additionally, clinicians and researchers should be aware that the type of prefabricated foot orthoses used did not change gluteus medius muscle activity over 4 weeks. Future research should aim to explore this relationship between foot type and gluteus medius muscle activity in larger sample sizes, consider the potential role of other lower extremity muscles and biomechanical variables, and investigate if these findings also occur in people with pathology.

Reduction of Knee Pain in a 45-Year-Old Woman After Pelvic Manipulation and Kinesiology Taping: A Case Report

Objective

The purpose of this case report is to describe the chiropractic management of a patient with knee pain stemming from pelvic imbalance.

Clinical Features

A female patient presented to a chiropractic clinic with ongoing anteromedial knee pain whenever she walks. The patient reported being unable to walk a half mile without her knee feeling like it would "give out."

Intervention and Outcome

The patient received 5 treatments focusing on the pelvic imbalance and reduced muscle strength discovered in the patient's initial evaluation. Chiropractic manipulation of the sacroiliac joint, kinesiology taping, and gluteus medius exercises were administered. The Verbal Rating Scale, muscle strength assessment, and orthopedic evaluation measured the patient's progress. After 5 treatments the Verbal Rating Scale went from 8 to 1 and gluteus medius strength scored 5 of 5.

Conclusion

The patient in this case reported resolution of her knee pain after 5 treatments over the course of 10 days. The patient reported no pain while walking nor while performing other activities of daily living. Although this is one case, correcting pelvic balance via conservative measures resolved the knee pain. Implementing therapy proximal to the complaint may be a viable option for patients with knee pain.

Reliability of surface electromyography for the gluteus medius muscle during gait in people with and without chronic nonspecific low back pain

The purpose of this study was to determine the intratester reliability of surface electromyography (EMG) assessment of the gluteus medius muscle in healthy people and people with chronic nonspecific low back pain (CNLBP) during barefoot walking. Gluteus medius muscle activity was measured twice in 40 people without and 30 people with CNLBP approximately 7 days apart. Walking gluteus medius muscle activity was normalised to maximal voluntary isometric contractions during side-lying hip abduction with manual resistance. Good intratester reliability (ICC > 0.75) was found for mean, peak, and peak to peak amplitude for healthy people. Only mean amplitude demonstrated good intratester reliability in those with CNLBP. Peak amplitude and peak to peak amplitude of the gluteus medius muscle of those with CNLBP, and the time of peak amplitude in both groups, demonstrated moderate reliability (ICC ranged from 0.50 to 0.58). Moderate to large standard error of measurement and minimal detectable change values were reported for outcome measurements. These results suggest that potentially large levels of random error can occur between sessions. Future research can build on this study for those with pathology and attempt to establish change values for EMG that are clinically meaningful.

Effects of core stabilization exercises on thickness and activity of trunk and hip muscles in subjects with nonspecific chronic low back pain

BACKGROUND

Changes in trunk and hip muscles are believed to be important in subjects with nonspecific chronic low back pain (NSCLBP), but little is known about specific changes, or how they might be affected by core stabilization exercises. The aim of this study was to compare six key muscles before and after these exercises.

METHODS

Thirty two NSCLBP patients were assigned randomly into two groups: exercise (n = 17) and control (n = 15). On 5 days per week for 4 weeks, the Exercise group performed 16 core stabilization exercises and the Control group received transcutaneous electrical nerve stimulation and a 'hot-pack'. Surface electromyography (EMG) was used to assess maximum bilateral activity of transversus abdominis (TrA), multifidus (MF) and gluteus maximus (Gmax) muscles. Ultrasound imaging was used to measure the rest and contracted thickness of these muscles. Pain and disability were assessed using a visual analogue scale (VAS) and the Oswestry Disability Index.

RESULTS

When left and right-side muscle data were combined, two-way ANOVAs showed a nonsignificant interaction effect for all dependent variables (P > 0.05), significant time effects on resting muscle thickness for TrA (P = 0.01), MF (P = 0.041) and Gmax (P = 0.003), EMG signals of TrA (P = 0.038), pain and disability (P = 0.000). There were a significant group effect on contracted thickness for TrA (P = 0.032) and Gmax (P = 0.026) and disability (P = 0.017).

CONCLUSIONS

Core stabilization exercises increased contracted thickness of TrA and Gmax muscles and decreased disability in subjects with NSCLBP.

Effects of a Gluteal Muscles Specific Exercise Program on the Vertical Jump

The vertical jump is a complex movement where many factors are involved in the final result. Currently, how a specific exercise program for gluteal muscles can affect the vertical jump is unknown. So, the aim of this study was to examine the effect of a specific exercise program for the gluteal muscles on a vertical jump. Forty-nine amateur athletes completed an 8-week program. The experimental group received a specific gluteal muscle training program in addition to their regular training routine, whereas the control group received their regular training routine. Jump height, flight time, speed and power were assessed (baseline, postintervention, and 4-week follow-up). Repeated-measures analyses of variance were conducted with ∝ ≤ 0.05. We calculated Eta squared effect sizes with 95% confidence intervals. Measurements at 8 weeks revealed significant increases in the experimental group compared to the control group for the values: jump height (p < 0.05) (experimental group = 17.15%; control group = 3.09%), flight time (p < 0.001) (experimental group = 7.98%; control group = 3.52%), speed (p < 0.01) (experimental group = 1.96%; control group = 1.83%) and power (p < 0.05) (experimental group = 4.43%; control group = 0.32%). However, at follow-up, these changes were not maintained. These data suggest that this specific training protocol for the gluteal muscles is effective in order to improve vertical jump performance in amateur athletes who use the vertical jump in their routine training habits.

Effects of Tibiofibular and Ankle Joint Manipulation on Hip Strength and Muscle Activation

OBJECTIVES

The purpose of this study was to determine whether high-velocity, low-amplitude ankle region manipulations could increase force output and muscle activation of hip musculature in individuals with a history of ankle sprain and unilateral tensor fascia latae (TFL) weakness during muscle testing.

METHODS

This investigation used a single-arm repeated measures design. Twenty-five participants' force outputs were tested at three time points (before manipulation, immediately after manipulation, and 48 hours after manipulation), and muscle activation of the rectus femoris, gluteus medius, and TFL was measured before and immediately after manipulation. Manipulations were applied to the talocrural, subtalar, proximal, and distal tibiofibular joints of the weaker limb. No contralateral manipulations were applied. Two-way repeated measures analysis of variance was used to compare maximal and average force production for each limb. In addition, paired t tests were used to compare muscle activation before and after manipulations.

RESULTS

There was a significant limb × time interaction. The involved limb average force increased from before manipulation (65.7 N) to 48 hours after manipulation (77.8 N; P = .014), maximal force increased (76.9 N) 48 hours after manipulation (87.8 N; P = .030), and gluteus medius activation increased (9.8% maximum, 12.2% average) immediately after manipulation. No significant differences were found in the uninvolved limb.

CONCLUSION

The results of this study suggest that high-velocity, low-amplitude ankle region manipulations might improve hip abductor strength in individuals with a history of ankle sprain and unilateral weakness during a TFL muscle test.