Single leg squat ratings by clinicians are reliable and predict excessive hip internal rotation moment

A comprehensive two-dimensional scoring system to assess the single-leg squat task in football players

BACKGROUND

The single-leg squat (SLS) is a safe and widespread functional test commonly performed in the mid-stages of rehabilitation after severe knee injuries. The use of reliable objective measures has been advocated to improve the quality of SLS assessment. The aim of this study was to describe a qualitative whole-body scoring system based on two-dimensional (2D) video analysis during SLS test and validate it against three-dimensional (3D) kinetics and kinematics.

METHODS

Thirty-four competitive football (soccer) players performed a series of SLS tasks. 3D kinematics and kinetics were collected through infrared cameras, and 2D video analysis was performed through a scoring system with sub-scores ranging from 0/2 (non-adequate movement) to 2/2 (adequate movement) based on frontal and lateral planes objective measurements. 3D kinematics and kinetics were grouped according to the results of the 2D evaluation and compared through the analysis of variance (P < 0.05).

RESULTS

Higher hip adduction, hip internalrotation, and knee valgus collapse were found in trials rated 0/2 or 1/2 compared with theone rated 2/2 in the limb stability score. Hip flexion and hip/knee moment ratio were lower in those scoring 0/2 comparedwith those scoring 2/2 in the movement strategy criterion. A low total score was associated with higherknee valgus collapse and lower hip/knee extensor moment ratio. Compensatory strategieswere found in frontal plane scores.

CONCLUSIONS

The 2D scoring system described was strongly associated with kinematics and kinetics from gold-standard 3D motion capture and might represent a valid tool to describe the movement quality of an SLS task.

Academic Department of Military Rehabilitation (ADMR): avoiding the pitfalls of 'the Walker Dip'

A key research theme identified during the 2021 Strategic Delivery Plan (SDP) for Defence Medical Services (DMS) Research was preventing and treating musculoskeletal injury (MSKI). MSKI is a significant burden to military populations globally, reducing both operational strength and force readiness. It is therefore essential that research is conducted to gain a greater understanding of the epidemiology, aetiology and risk factors associated with MSKI to develop targeted prevention strategies and rehabilitation interventions. The Academic Department of Military Rehabilitation (ADMR) and the recently established MSKI research-theme working group must use a combination of balance and flexibility when coordinating research priorities to ensure they align and reflect both higher level DMS and UK Defence Rehabilitation practitioner-driven priorities. This article describes the response ADMR have taken to meet and align with the requirements of the 2021 SDP.

Evaluation of functional tests performance using a camera-based and machine learning approach

The objective of this study is to evaluate the performance of functional tests using a camera-based system and machine learning techniques. Specifically, we investigate whether OpenPose and any standard camera can be used to assess the quality of the Single Leg Squat Test and Step Down Test functional tests. We recorded these exercises performed by forty-six healthy subjects, extract motion data, and classify them to expert assessments by three independent physiotherapists using 15 binary parameters. We calculated ranges of movement in Keypoint-pair orientations, joint angles, and relative distances of the monitored segments and used machine learning algorithms to predict the physiotherapists' assessments. Our results show that the AdaBoost classifier achieved a specificity of 0.8, a sensitivity of 0.68, and an accuracy of 0.7. Our findings suggest that a camera-based system combined with machine learning algorithms can be a simple and inexpensive tool to assess the performance quality of functional tests.

ADAPTations to low load blood flow restriction exercise versus conventional heavier load resistance exercise in UK military personnel with persistent knee pain: protocol for the ADAPT study, a multi-centre randomized controlled trial

BACKGROUND

Muscle atrophy, muscle weakness and localised pain are commonly reported following musculoskeletal injury (MSKI). To mitigate this risk and prepare individuals to return to sport or physically demanding occupations, resistance training (RT) is considered a vital component of rehabilitation. However, to elicit adaptations in muscle strength, exercise guidelines recommend lifting loads ≥ 70% of an individual's one repetition maximum (1-RM). Unfortunately, individuals with persistent knee pain are often unable to tolerate such high loads and this may negatively impact the duration and extent of their recovery. Low load blood flow restriction (LL-BFR) is an alternative RT technique that has demonstrated improvements in muscle strength, hypertrophy, and pain in the absence of high mechanical loading. However, the effectiveness of high-frequency LL-BFR in a residential rehabilitation environment remains unclear. This study will compare the efficacy of high frequency LL-BFR to 'conventional' heavier load resistance training (HL-RT) on measures of physical function and pain in adults with persistent knee pain.

METHODS

This is a multicentre randomised controlled trial (RCT) of 150 UK service personnel (aged 18-55) admitted for a 3-week residential rehabilitation course with persistent knee pain. Participants will be randomised to receive: a) LL-BFR delivered twice daily at 20% 1-RM or b) HL-RT three-times per week at 70% 1-RM. Outcomes will be recorded at baseline (T1), course discharge (T2) and at three-months following course (T3). The primary outcome will be the lower extremity functional scale (LEFS) at T2. Secondary outcomes will include patient reported perceptions of pain, physical and occupational function and objective measures of muscle strength and neuromuscular performance. Additional biomechanical and physiological mechanisms underpinning both RT interventions will also be investigated as part of a nested mechanistic study.

DISCUSSION

LL-BFR is a rehabilitation modality that has the potential to induce positive clinical adaptations in the absence of high mechanical loads and therefore could be considered a treatment option for patients suffering significant functional deficits who are unable to tolerate heavy load RT. Consequently, results from this study will have a direct clinical application to healthcare service providers and patients involved in the rehabilitation of physically active adults suffering MSKI.

TRIAL REGISTRATION

ClinicalTrials.org reference number, NCT05719922.

High-Volume Image-Guided Injections in Achilles and Patellar Tendinopathy in a Young Active Military Population: A Double-Blind Randomized Controlled Trial

Background:

Chronic Achilles and patellar tendinopathy are a significant burden in physically active populations. High-volume image-guided injection (HVIGI) proposes to strip away associated neovascularity, disrupt painful nerve ingrowth, and facilitate rehabilitation.

Purpose:

To investigate the efficacy of HVIGI with and without steroid relative to placebo.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A total of 62 participants were recruited between May 25, 2016, and March 5, 2020. Participants were men aged 18 to 55 years with Achilles or patellar tendinopathy of at least 6-month chronicity that had not improved with nonoperative management (including physical therapy and shockwave therapy), with ultrasound evidence of neovascularization, tendon thickening, and echogenic changes. They were assigned to the following groups: control (3 mL of subcutaneous 0.5% bupivacaine), HVIGI (10 mL of 0.5% bupivacaine and 30 mL of normal saline, ultrasound-guided between tendon and underlying fat pad), or HVIGI with steroid (HVIGIwSteroid; 0.25 mL of 100 mg/mL hydrocortisone). Clinicians and assessors were blinded. All participants were supervised through a pain-guided progressive loading program for 6 months postinjection. The main outcome measures were the Victoria Institute of Sport Assessments (VISA) for Achilles and patellar tendinopathy and the visual analog scale (VAS) for pain at 6 months postinjection.

Results:

The VISA score improved by a mean of 22.8 points (95% CI, 10.4-35.3 points; effect size [ES], 1.51) in the control group (n = 21), 18.6 points (95% CI, 9.1-28.0 points; ES, 1.31) in the HVIGI group (n = 21), and 18.5 points (95% CI, 3.4-33.6 points; ES, 0.88) in the HVIGIwSteroid group (n = 20). VAS pain improved by a mean of 15 points (interquartile range [IQR], –38.75, 8 points; ES, 0.39) in controls, 13 points (IQR,–34.0, 3.75 points; ES, 0.47) in the HVIGI group, and 27 points (IQR,–38.0, –1.0 points; ES, 0.54) in the HVIGIwSteroid group. The main effects were significant for time (P < .001) but not group (P ≥ .48), with no group × time interaction (P = .71). One participant was lost to follow-up from each group, multiple imputation was used for missing data points. No adverse events occurred.

Conclusion:

Study findings did not demonstrate superiority of HVIGI over control injection.

Registration:

EU Clinical Trials Register (EudraCT: 2015-003587-36).

Measurement Properties of Clinically Accessible Movement Assessment Tools for Analyzing Single-Leg Squats and Step-Downs: A Systematic Review

CONTEXT

Poor lower-extremity biomechanics are predictive of increased risk of injury. Clinicians analyze the single-leg squat (SLS) and step-down (SD) with rubrics and 2D assessments to identify these poor lower-extremity biomechanics. However, evidence on measurement properties of movement assessment tools is not strongly outlined. Measurement properties must be established before movement assessment tools are recommended for clinical use.

OBJECTIVE

The purpose of this study was to systematically review the evidence on measurement properties of rubrics and 2D assessments used to analyze an SLS and SD.

EVIDENCE ACQUISITION

The search strategy was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. The search was performed in PubMed, SPORTDiscus, and Web of Science databases. The COnsensus-based Standards for the selection of health Measurement INstruments multiphase procedure was used to extract relevant data, evaluate methodological quality of each study, score the results of each movement assessment, and synthesize the evidence.

EVIDENCE SYNTHESIS

A total of 44 studies were included after applying eligibility criteria. Reliability and construct validity of knee frontal plane projection angle was acceptable, but criterion validity was unacceptable. Reliability of the Chmielewski rubric was unacceptable. Content validity of the knee-medial-foot and pelvic drop rubrics was acceptable. The remaining rubrics and 2D measurements had inconclusive or conflicting results regarding reliability and validity.

CONCLUSIONS

Knee frontal plane projection angle is reliable for analyzing the SLS and SD; however, it does not serve as a substitute for 3D motion analysis. The Chmielewski rubric is not recommended for assessing the SLS or SD as it may be unreliable. Most movement assessment tools yield indeterminate results. Within the literature, standardized names, procedures, and reporting of movement assessment tool reliability and validity are inconsistent.

Biomechanical differences between military patients with patellar tendinopathy and asymptomatic controls during single-leg squatting and gait - A statistical parametric mapping study

BACKGROUND

Prior identification of biomechanical differences between patients with patellar tendinopathy and healthy controls has utilised time-discrete analysis which is susceptible to type I error when multiple comparisons are uncorrected. We employ statistical parametric mapping to minimise the risk of such error, enabling more appropriate clinical decision-making.

METHODS

Lower-limb biomechanics of 21 patients with patellar tendinopathy and 22 controls were captured during walking and three types of squats. A statistical parametric mapping two-sample t-test was used to identify kinematic and kinetic differences between groups for each joint. Paired t-tests were used to compare pain before and after tasks, in patients with patellar tendinopathy.

FINDINGS

During walking, cases demonstrated reduced knee joint power during initial contact and hip joint power during terminal stance. In squatting, cases demonstrated increased knee abduction angles at various time points of the small knee bend and single-leg squat. Cases demonstrated reduced knee internal rotation moment during the deepest portion of the single-leg squat and single-leg decline squat.

INTERPRETATION

Gait appears unaffected by patellar tendinopathy, likely due to low task difficulty. Elevated knee abductions angles during squatting were confirmed as a key difference in patients with patellar tendinopathy. Reduced knee internal rotation moments in patients were attributed to a potential reduction in hip external rotator strength and possible pain avoidance strategy; however further evidence is required to substantiate these claims. Findings provide a clear rationale for rehabilitation programs to focus on knee stabilisation and strengthening of the muscles surrounding the hip.

Visual assessment of movement quality: a study on intra- and interrater reliability of a multi-segmental single leg squat test

Background

The Single Leg Squat test (SLS) is a common tool used in clinical examination to set and evaluate rehabilitation goals, but there is not one established SLS test used in the clinic. Based on previous scientific findings on the reliability of the SLS test and with a methodological rigorous setup, the aim of the present study was to investigate the intra- and interrater reliability of a standardised multi-segmental SLS test.

Methods

We performed a study of measurement properties to investigate the intra- and interrater reliability of a standardised multi-segmental SLS test including the assessment of the foot, knee, pelvis, and trunk. Novice and experienced physiotherapists rated 65 video recorded SLS tests from 34 test persons. We followed the Quality Appraisal for Reliability Studies checklist.

Results

Regardless of the raters experience, the interrater reliability varied between “moderate” for the knee variable (ĸ = 0.41, 95% CI 0.10–0.72) and “almost perfect” for the foot (ĸ = 1.00, 95% CI 1.00–1.00). The intrarater reliability varied between “slight” (pelvic variable; ĸ = 0.17, 95% CI -0.22-0.55) to “almost perfect” (foot variable; ĸ = 1.00, 95% CI 1.00–1.00; trunk variable; ĸ = 0.82, 95% CI 0.66–0.97). A generalised kappa coefficient including the values from all raters and segments reached “moderate” interrater reliability (ĸ = 0.52, 95% CI 0.43–0.61), the corresponding value for the intrarater reliability reached “almost perfect” (ĸ = 0.82, 95% CI 0.77–0.86).

Conclusions

The present study shows a “moderate” interrater reliability and an “almost perfect” intrarater reliability for the variable all segments regardless of the raters experience. Thus, we conclude that the proposed standardised multi-segmental SLS test is reliable enough to be used in an active population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13102-021-00289-x.

Relationship between passive ankle dorsiflexion range, dynamic ankle dorsiflexion range and lower limb and trunk kinematics during the single-leg squat

BACKGROUND

Limited passive ankle dorsiflexion range has been associated with increased knee valgus during functional tasks. Increased knee valgus is considered a contributing factor for musculoskeletal disorders in the lower limb. There is conflicting evidence supporting this association. The extent of passive ankle dorsiflexion range is associated with dynamic ankle dorsiflexion range and the way how these variables are related to lower limb or trunk kinematics is unclear.

RESEARCH QUESTION

What is the association between passive ankle dorsiflexion range or dynamic ankle dorsiflexion range with shank, thigh, pelvis or trunk movements during the single-leg squat?

METHODS

This is a cross-sectional study with a convenience sample. Thirty uninjured participants performed the single-leg squat with their dominant limb. Ankle, shank, thigh, pelvis and trunk 3D kinematics were recorded. Passive ankle dorsiflexion range was assessed through the weight-bearing lunge test and the dynamic ankle dorsiflexion range was defined as the ankle dorsiflexion range of motion in the sagittal plane during the single-leg squat.

RESULTS

Greater passive ankle dorsiflexion range was associated with smaller thigh internal rotation (r= -0.38). Greater dynamic ankle dorsiflexion range was associated with smaller trunk flexion (r = 0.59) and pelvis anteversion (r= -0.47). Passive ankle dorsiflexion range and dynamic ankle dorsiflexion range were not associated.

SIGNIFICANCE

Greater passive ankle dorsiflexion range seems to be associated with a better lower limb alignment during the single-leg squat, while dynamic ankle dorsiflexion range seems to reflect different lower limb and trunk kinematic strategies.

Single-Leg Squat After Anterior Cruciate Ligament Reconstruction: An Analysis of the Knee Valgus Angle at 6 and 12 Months

Background:

Deficits in neuromuscular control are common after anterior cruciate ligament (ACL) reconstruction and may be associated with further knee injury. The knee valgus angle during a single-leg squat (SLS) is one measure of neuromuscular performance.

Purpose:

To determine whether the knee valgus angle during SLS changes between 6 and 12 months after ACL reconstruction and to assess how the operative knee valgus angle compares with that of the contralateral side.

Study Design:

Case series; Level of evidence, 4.

Methods:

A cohort of 100 patients with uninjured contralateral knees were assessed at 6 and 12 months after primary hamstring autograft ACL reconstruction. Participants performed the SLS on each leg, and the knee valgus angle was measured via frame-by-frame video analysis at 30° of flexion and at each patient’s maximum knee flexion angle.

Results:

For the operative limb at 30° of flexion, a small but statistically significant reduction was noted in the valgus angle between 6 and 12 months (5.46° vs 4.44°; P = .002; effect size = 0.24). At 6 months, a slightly higher valgus angle was seen in the operative limb compared with the nonoperative limb (5.46° vs 4.29°; P = .008; effect size = 0.27). At maximum flexion, no difference was seen between limbs in the valgus angle at either 6 or 12 months, and no change was seen in the operative limb between 6 and 12 months. At 6 months and 30° of knee flexion, 13 patients had a valgus angle greater than 10°. This group also had a higher mean valgus angle in the contralateral limb compared with the contralateral limb in the other 87 patients (8.5° vs 3.65°; P < .001).

Conclusion:

During a controlled SLS, the knee valgus angle remained essentially constant, and minimal limb asymmetries were present over the 6- to 12-month postoperative period, a time when athletes typically increase their activity levels. Whether changes or asymmetries will be seen with more dynamically challenging tasks remains to be determined. When present, high valgus angles were commonly bilateral.

Visual rating of movement quality in individuals with and without a history of intra-articular knee injury

Objective: To investigate the use of visually rated movement quality in a group including those with a history of intra-articular knee injury.Design: Historical cohort study.Setting: Laboratory.Participants: A total of 115 youth and young adults (62 previously injured).Main outcome measures: Inter-rater agreement for ratings of movement quality during single limb squat and vertical drop jump (VDJ) were assessed. Odds ratios were calculated to determine if the history of knee injury was associated with greater odds of poor movement quality. The difference in knee:ankle separation ratio between the injured and uninjured groups was compared.Results: Rater agreement was moderate to excellent (κ = 0.55 to 0.93). Comparing the injured and uninjured limb in previously injured participants or injured participants to matched uninjured controls, there was no significant difference in the proportion of good versus poor movement ratings (diff = 0% to 10%; p ≥ 0.23). Prior history of knee injury did not increase the odds of poor movement quality during the VDJ (OR 0.91; 95% CI 0.41 to 2.03) or single leg squat (OR 1.04; 95% CI 0.38 to 2.85) and there was no significant difference in the knee:ankle separation ratios (mean diff -0.03; p = 0.30).Conclusion: Visual rating of movement in individuals with and without a history of knee injury is reliable. A history of knee injury does not increase the likelihood of poor visually rated movement quality.

Sport Specialization and Single-Legged-Squat Performance Among Youth Baseball and Softball Athletes

CONTEXT

Previous research has indicated that throwing sports expose athletes to overuse injuries and that specialization in sport is linked to injury. However, the effect of overexposure to a throwing sport on a dynamic movement task is unknown.

OBJECTIVE

To determine if sport specialization in youth throwing athletes affected performance on the single-legged squat (SLS).

DESIGN

Descriptive laboratory study.

SETTING

University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 49 youth baseball and softball athletes (23 baseball, 26 softball; age = 12.96 ± 2.32 years, height = 165.01 ± 13.05 cm, mass = 61.42 ± 13.04 kg) were recruited.

MAIN OUTCOME MEASURE(S)

Participants were grouped into 3 categories based on specialization definitions: (1) 8 months or longer in season, (2) 8 months or longer in training, or (3) 8 months or longer in season and previously quit another sport. We measured SLS kinematics and used a set of 1-way multivariate analyses of variances to determine if trunk kinematics differed by group.

RESULTS

Athletes who spent 8 months or more in sport-specific training exhibited significantly more trunk control, revealed by less trunk lateral flexion (Λ = 0.69, F_6,38 = 2.89, P = .020) and less trunk flexion (Λ = 0.69, F_6,38 = 2.88, P = .021) throughout an SLS.

CONCLUSIONS

These results agree with the principle of specific adaptation to imposed demands. Surprisingly, athletes who spent 8 months or more playing a unilateral sport showed no differences in SLS performance. Clinicians should emphasize that neuromuscular adaptations of the lumbopelvic-hip complex for dynamic movement, such as an SLS, may be achieved through training instead of strict sport participation. Future researchers should consider how much of the training protocol is actually specialized for sport training.

Visual assessment of movement quality in the single leg squat test: a review and meta-analysis of inter-rater and intrarater reliability

Single leg squat (SLS) is a common tool used in clinical examination to set and evaluate rehabilitation goals, but also to assess lower extremity function in active people.

Kinematic and kinetic differences between military patients with patellar tendinopathy and asymptomatic controls during single leg squats

BACKGROUND

Knee valgus alignment has been associated with lower-limb musculoskeletal injury. This case-control study aims to: assess biomechanical differences between patients with patellar tendinopathy and healthy controls.

METHODS

43 military participants (21 cases, 22 controls) were recorded using 3D-motion capture performing progressively demanding, small knee bend, single leg and single leg decline squats. Planned a priori analysis of peak: hip adduction, knee flexion, pelvic tilt, pelvic obliquity and trunk flexion was conducted using MANOVA. Kinematic and kinetic data were graphed with bootstrapped t-tests and 95% CI's normalised to the squat cycle. ANOVA and correlations in SPSS were used for exploratory analysis.

FINDINGS

On their symptomatic side cases squatted to less depth (-6.62°, p < 0.05) than controls with exploratory curve analysis revealing a pattern of increased knee valgus collapse throughout the squatting movement (p < 0.05). Greater patella tendon force was generated by: the eccentric than concentric phase of squatting (+30-43%, ES 0.52-1.32, p < 0.01), declined (plantarflexed) compared to horizontal surface (+36-51%, ES 1.19-1.68, p < 0.01) and deeper knee flexion angles (F ≥ 658.3, p < 0.01) with no difference between groups (F ≤ 1.380, p > 0.05). Cases experienced more pain on testing on decline board (ES = 0.69, p < 0.01). For symptomatic limbs pain (r_s = 0.458-0.641, p ≤ 0.05), but not VISA-P (Victoria Institute of Sport Assessment) (r_s = 0.053-0.090, p > 0.05), correlated with extensor knee moment.

INTERPRETATION

Knee valgus alignment is a plausible risk factor for patellar tendinopathy. Conclusions relating to causation are limited by the cross-sectional study design. Increasing squat depth, use of a declined surface and isolating the eccentric phase enable progression of loading prescription guided by pain.

Is there a correlation in frontal plane knee kinematics between running and performing a single leg squat in runners with patellofemoral pain syndrome and asymptomatic runners?

BACKGROUND

Knee kinematics when running, specifically knee valgus, have been linked to patellofemoral pain syndrome. Assessing running biomechanics requires skill, equipment and time. Clinically, the single leg squat is used to make inferences about knee kinematics during running. No evidence supports this practice.

METHODS

Sixteen asymptomatic runners and sixteen runners with patellofemoral pain syndrome were recruited. Asymptomatic runners were sub-divided by dominant and non-dominant leg and runners with patellofemoral pain syndrome by painful and non-painful leg. This gave four groups. Participants were videoed performing single leg squats and running on a treadmill. Frontal plane knee kinematics were calculated using the frontal plane projection angle. Correlation in frontal plane projection angle between running and single leg squat were calculated using Pearson's correlation coefficient. Differences in frontal plane projection angle between groups for running and single leg squat were calculated using multiple independent t-tests with Bonferroni correction.

FINDINGS

Correlation in frontal plane projection angle between running and the single leg squat was not statistically significant for the painful leg group (p = 0.19) but was for the remaining groups (p < 0.05). There was no statistically significant difference in frontal plane projection angle between the four groups when running. Single leg squat frontal plane projection angle was significantly larger for the painful leg group (10.3°) than the dominant leg (-0.2° (p = 0.003)) and non-dominant leg (-0.4° (p = 0.004)) in the asymptomatic runners group.

INTERPRETATION

The single leg squat cannot be used to make inferences about frontal plane knee kinematics in running gait in patellofemoral pain syndrome sufferers.

Accuracy of movement quality screening to document effects of neuromuscular control retraining exercises in a young ex-footballer with hip and groin symptoms: A proof of concept case study

Hip and groin pain is common in footballers and altering movement patterns can reduce symptoms. Observational tests of movement control are thought to identify abnormal movement patterns, but their accuracy needs yet to be confirmed by comparison with an objective measure. To assess the accuracy, using 3D motion analysis, of observational movement control tests and their ability to detect changes, and document changes in symptoms following a neuromuscular control exercise programme in an ex-footballer with hip and groin pain. A 25-year-old male with chronic bilateral hip and groin pain had their movement control ability rated and kinematic data collected using 3D motion analysis while performing Small Knee Bend (SKB) and SKB with Rotation (SKB Rot) tests pre-and post-neuromuscular control exercise training. Movement control was rated as at fault if they were unable to control specific trunk and pelvic movements during the tests. The Copenhagen Hip and Groin Outcome Score (HAGOS) was used to assess symptoms. Following the intervention, observational rating during the SKB test improved from fault to no fault for anterior pelvic tilt, which decreased by 17° and 16° during right and left leg SKB tests respectively. The HAGOS symptoms subsection improved from 36% to 61%. Observational movement screening ratings were supported by 3-D motion analysis. These findings indicate that the screening tool was accurate for detecting improvements in trunk and pelvic movement control following an exercise programme in an ex-footballer who had presented with hip and groin pain.