Clinical assessment of hip strength using a hand-held dynamometer is reliable

Reliability of concentric and eccentric strength of hip abductor and adductor muscles in young soccer players

The concentric and eccentric strength profile and muscular balance of the hip joint are important parameters for success in soccer. This study evaluated the reliability for the assessment of hip abduction and adduction isokinetic strength over a range of angular velocities (30 and 90°/s) and types of muscular actions (concentric and eccentric) in young soccer players. The reliability for the assessment of reciprocal (conventional and functional) and bilateral torque ratios was also examined. Fifteen male soccer players (15±1 years) performed two sessions, separated by three days. The testing protocol consisted of five maximal concentric and eccentric hip abductions and adductions of both legs at angular velocities of 30°/s and 90°/s. The peak torque was evaluated in young soccer players using an isokinetic dynamometer (Cybex Norm), and the reciprocal strength ratios (conventional and functional) and bilateral ratios (non-preferred to preferred leg ratios) were calculated. The test-retest reliability for the assessment of peak torque (ICC = 0.71-0.92) and of reciprocal muscle group ratios (ICC = 0.44-0.87) was found to be moderate to high. Bilateral torque ratios exhibited low to moderate reliability (ICC = 0.11-0.64). In conclusion, isokinetic strength of hip abductor and adductor muscles and the conventional and functional strength ratios can be reliably assessed in young soccer players, especially at low angular velocities. The assessment, however, of bilateral strength ratios for hip abductor/adductor muscles should be interpreted with more caution.

Hip adduction and abduction strength profiles in elite, sub-elite and amateur Australian footballers

OBJECTIVES

It has been reported that obtaining an adduction-to-abduction strength ratio of 90-100%, and an adduction strength equal to that of the uninjured side, are suitable clinical milestones for return to sport following groin injury. Little is known about hip adduction and abduction strength profiles in Australian footballers. This study aimed to compare isometric hip adduction and abduction strength profiles between preferred and non-preferred kicking legs in elite, sub-elite and amateur Australian footballers.

DESIGN

Cross sectional study

METHODS

36 elite, 19 sub-elite and 18 amateur Australian footballers, with a mean age of 24, 19 and 23 years respectively, were included. Maximal hip isometric adduction and abduction strength were measured using a hand held dynamometer with external belt fixation.

RESULTS

There were no significant differences in isometric hip adduction (p=0.262) or abduction (p=0.934) strength, or the adduction-to-abduction ratio (p=0.163), between preferred and non-preferred kicking legs, regardless of playing level. Elite players had significantly greater isometric hip adduction and abduction strength than both sub-elite (mean difference; adduction=46.01N, p<0.001, abduction=30.79N, p=0.003) and amateur players (mean difference; adduction=78.72N, p<0.001, abduction=59.11N, p<0.001). There was no significant difference in the adduction-to-abduction ratio between the playing levels (p=0.165).

CONCLUSIONS

No significant differences were found between preferred and non-preferred kicking legs across the playing levels for isometric hip adduction, abduction or the adduction-to-abduction ratio. This may have implications for developing groin injury prediction and return to sport criteria in Australian footballers.

Association Between Anatomical Characteristics, Knee Laxity, Muscle Strength, and Peak Knee Valgus During Vertical Drop-Jump Landings

STUDY DESIGN

Controlled laboratory study; cross-sectional.

OBJECTIVES

To investigate the relationship among anatomical variables, knee laxity, muscle strength, and peak knee valgus angles during a vertical drop-jump landing task.

BACKGROUND

Excessive knee valgus has been associated with anterior cruciate ligament injury in females; however, the influence of anatomical characteristics, knee laxity, and muscle strength on frontal plane knee motion is not completely understood.

METHODS

Norwegian elite female soccer players (n = 279; mean ± SD age, 21 ± 4 years; height, 167 ± 6 cm; body mass, 63 ± 7 kg) were evaluated from 2009 through 2012. The evaluation included 3-D motion analysis of a vertical drop jump, anatomical measures (height, static knee valgus, leg length, and static foot posture), knee laxity, and muscle strength (quadriceps, hamstrings, and hip abductors). Multiple linear regression analyses were used to investigate the relationships among anatomical characteristics, knee laxity, muscle strength, and peak knee valgus angles.

RESULTS

Anatomical characteristics explained 11% of the variance in peak knee valgus angles (P<.001), with height and static knee valgus being significant predictors.

CONCLUSION

Greater body height and static knee valgus were associated with greater peak knee valgus angles during a vertical drop-jump landing task. However, these variables only explained 11% of the variance in peak knee valgus.

Hip Strength Deficits in Patients With Symptomatic Femoroacetabular Impingement and Labral Tears

PURPOSE

To determine the prevalence of hip strength deficits in a consecutive cohort of patients with unilateral femoroacetabular impingement (FAI) compared with the asymptomatic contralateral hip.

METHODS

Fifty consecutive patients undergoing hip arthroscopy for symptomatic FAI underwent preoperative hip strength dynamometer measurements and were included in the study. Manual isometric hip strength measurements were performed with a handheld dynamometer and included measurements of various hip strengths (flexion, extension, adduction, abduction, internal rotation, and external rotation). Weakness greater than or equal to 10% for any given measurement was defined as a strength deficit in this study. Clinical data including age, gender, size of labral tear, and preoperative outcome scores were recorded. Outcome scores included the modified Harris Hip Score and Short Form 12 Physical Component.

RESULTS

The mean age of patients in the study was 32.0 years (range, 18.1 to 49.8 years). There were 32 male and 18 female patients. Hip abduction strength deficits were seen in 46% of patients and flexion strength deficits in 42% of patients. An 8% decrease in strength of the involved hip was seen in flexion, and an 8.7% decrease was seen in abduction. Patients with hip flexion strength deficits had a loss of function (mean modified Harris Hip Score, 57.8 v 66.1; P = .021) and larger labral tears (mean, 39 mm v 28 mm; P = .003). Hip flexion strength deficits correlated with loss of hip flexion (r = 0.373, P = .008).

CONCLUSIONS

Hip strength deficits were common in patients presenting with unilateral symptomatic FAI and occurred most commonly in hip abduction and flexion. Strength deficits in hip flexion were associated with decreased function, loss of motion, and larger labral tears in patients with FAI and labral tears.

LEVEL OF EVIDENCE

Level IV, prognostic case series.

Assessment of Lower Limb Muscle Strength and Power Using Hand-Held and Fixed Dynamometry: A Reliability and Validity Study

Introduction

Hand-held dynamometry (HHD) has never previously been used to examine isometric muscle power. Rate of force development (RFD) is often used for muscle power assessment, however no consensus currently exists on the most appropriate method of calculation. The aim of this study was to examine the reliability of different algorithms for RFD calculation and to examine the intra-rater, inter-rater, and inter-device reliability of HHD as well as the concurrent validity of HHD for the assessment of isometric lower limb muscle strength and power.

Methods

30 healthy young adults (age: 23±5yrs, male: 15) were assessed on two sessions. Isometric muscle strength and power were measured using peak force and RFD respectively using two HHDs (Lafayette Model-01165 and Hoggan microFET2) and a criterion-reference KinCom dynamometer. Statistical analysis of reliability and validity comprised intraclass correlation coefficients (ICC), Pearson correlations, concordance correlations, standard error of measurement, and minimal detectable change.

Results

Comparison of RFD methods revealed that a peak 200ms moving window algorithm provided optimal reliability results. Intra-rater, inter-rater, and inter-device reliability analysis of peak force and RFD revealed mostly good to excellent reliability (coefficients ≥ 0.70) for all muscle groups. Concurrent validity analysis showed moderate to excellent relationships between HHD and fixed dynamometry for the hip and knee (ICCs ≥ 0.70) for both peak force and RFD, with mostly poor to good results shown for the ankle muscles (ICCs = 0.31–0.79).

Conclusions

Hand-held dynamometry has good to excellent reliability and validity for most measures of isometric lower limb strength and power in a healthy population, particularly for proximal muscle groups. To aid implementation we have created freely available software to extract these variables from data stored on the Lafayette device. Future research should examine the reliability and validity of these variables in clinical populations.

Reliability of the hand held dynamometer in measuring muscle strength in people with interstitial lung disease

OBJECTIVE

To evaluate the inter-rater and intra-rater reliability of the hand held dynamometer in measuring muscle strength in people with interstitial lung disease (ILD).

DESIGN

Test retest reliability of hand-held dynamometry for elbow flexor and knee extensor strength between two independent raters and two testing sessions.

SETTING

Physiotherapy department within a tertiary hospital.

PARTICIPANTS

Thirty participants with ILD of varying aetiology were included. Twenty participants completed the inter-rater reliability protocol (10 idiopathic pulmonary fibrosis, mean (SD) age 73 (10) years, 11 male) and 21 participants completed the intra-rater reliability protocol (10 idiopathic pulmonary fibrosis, mean age 71 (10) years, 11 male).

MAIN OUTCOME MEASURES

Mean muscle strength (kg). Agreement between the two raters and testing sessions was analyzed using Bland-Altman plots and reliability was estimated using intraclass correlation coefficients (ICC).

RESULTS

For elbow flexor strength there was a mean difference between raters of -0.6kg (limits of agreement (LOA) -5.6 to 4.4kg) and within raters of -0.3kg (LOA -2.8 to 2.3kg). The ICCs were 0.95 and 0.98, respectively. For knee extensor strength there was a mean difference between raters of -1.5kg (LOA -6.9 to 3.9kg) and within raters of -0.7kg (LOA -3.9 to 2.4kg). The ICCs were 0.95 and 0.97, respectively.

CONCLUSIONS

Hand-held dynamometry is reliable in measuring elbow flexor and knee extensor strength in people with ILD.

Isometric and isokinetic hip strength and agonist/antagonist ratios in symptomatic femoroacetabular impingement

OBJECTIVES

This study investigated isometric and isokinetic hip strength in individuals with and without symptomatic femoroacetabular impingement (FAI). The specific aims were to: (i) determine whether differences exist in isometric and isokinetic hip strength measures between groups; (ii) compare hip strength agonist/antagonist ratios between groups; and (iii) examine relationships between hip strength and self-reported measures of either hip pain or function in those with FAI.

DESIGN

Cross-sectional.

METHODS

Fifteen individuals (11 males; 25±5 years) with symptomatic FAI (clinical examination and imaging (alpha angle >55° (cam FAI), and lateral centre edge angle >39° and/or positive crossover sign (combined FAI))) and 14 age- and sex-matched disease-free controls (no morphological FAI on magnetic resonance imaging) underwent strength testing. Maximal voluntary isometric contraction strength of hip muscle groups and isokinetic hip internal (IR) and external rotation (ER) strength (20°/s) were measured. Groups were compared with independent t-tests and Mann-Whitney U tests.

RESULTS

Participants with FAI had 20% lower isometric abduction strength than controls (p=0.04). There were no significant differences in isometric strength for other muscle groups or peak isokinetic ER or IR strength. The ratio of isometric, but not isokinetic, ER/IR strength was significantly higher in the FAI group (p=0.01). There were no differences in ratios for other muscle groups. Angle of peak IR torque was the only feature correlated with symptoms.

CONCLUSIONS

Individuals with symptomatic FAI demonstrate isometric hip abductor muscle weakness and strength imbalance in the hip rotators. Strength measurement, including agonist/antagonist ratios, may be relevant for clinical management of FAI.

Reliability of measuring hip abductor strength following total knee arthroplasty using a hand-held dynamometer

PURPOSE

To investigate the test-retest reliability of measuring hip abductor strength in patients with total knee arthroplasty (TKA) using a hand-held dynamometer (HHD) with two different types of resistance: belt and manual resistance.

METHOD

Test-retest reliability of 30 subjects (17 female, 13 male, 71.9 ± 7.4 years old), 9.2 ± 2.7 days post TKA was measured using belt and therapist resistance. Retest reliability was calculated with intra-class coefficients (ICC3,1) and 95% confidence intervals (CI) for both the group average and the individual scores. A paired t-test assessed whether a difference existed between the belt and therapist methods of resistance.

RESULTS

ICCs were 0.82 and 0.80 for the belt and therapist resisted methods, respectively. Hip abductor strength increases of 8 N (14%) for belt resisted and 14 N (17%) for therapist resisted measurements of the group average exceeded the 95% CI and may represent real change. For individuals, hip abductor strength increases of 33 N (72%) (belt resisted) and 57 N (79%) (therapist resisted) could be interpreted as real change.

CONCLUSIONS

Hip abductor strength can be reliably measured using HHD in the clinical setting with the described protocol. Belt resistance demonstrated slightly higher test-retest reliability.

IMPLICATIONS FOR REHABILITATION

Reliable measurement of hip abductor muscle strength in patients with TKA is important to ensure deficiencies are addressed in rehabilitation programs and function is maximized. Hip abductor strength can be reliably measured with a hand-held dynamometer in the clinical setting using manual or belt resistance.

Measuring Eccentric Strength of the Shoulder External Rotators Using a Handheld Dynamometer: Reliability and Validity

CONTEXT

Shoulder strength assessment plays an important role in the clinical examination of the shoulder region. Eccentric strength measurements are of special importance in guiding the clinician in injury prevention or return-to-play decisions after injury.

OBJECTIVE

To examine the absolute and relative reliability and validity of a standardized eccentric strength-measurement protocol for the glenohumeral external rotators.

DESIGN

Descriptive laboratory study.

SETTING

Testing environment at the Department of Rehabilitation Sciences and Physiotherapy of Ghent University, Belgium.

PATIENTS OR OTHER PARTICIPANTS

Twenty-five healthy participants (9 men and 16 women) without any history of shoulder pain were tested by 2 independent assessors using a handheld dynamometer (HHD) and underwent an isokinetic testing procedure.

INTERVENTION(S)

The clinical protocol used an HHD, a DynaPort accelerometer to measure acceleration and angular velocity of testing 30°/s over 90° of range of motion, and a Biodex dynamometer to measure isokinetic activity.

MAIN OUTCOME MEASURE(S)

Three eccentric strength measurements: (1) tester 1 with the HHD, (2) tester 2 with the HHD, and (3) Biodex isokinetic strength measurement.

RESULTS

The intratester reliability was excellent (0.879 and 0.858), whereas the intertester reliability was good, with an intraclass correlation coefficient between testers of 0.714. Pearson product moment correlation coefficients of 0.78 and 0.70 were noted between the HHD and the isokinetic data, showing good validity of this new procedure.

CONCLUSIONS

Standardized eccentric rotator cuff strength can be tested and measured in the clinical setting with good-to-excellent reliability and validity using an HHD.

Management of chronic recurrent osteitis pubis/pubic bone stress in a Premier League footballer: Evaluating the evidence base and application of a nine-point management strategy

BACKGROUND/AIM

The aim of this paper was to use a clinical example to describe a treatment strategy for the management of recurrent chronic groin pain and evaluate the evidence of the interventions.

METHODS

A professional footballer presented with chronic recurrent OP/PBS. The injury was managed successfully with a nine-point programme - 1. Acute pharmacological management. 2. Tone reduction of over-active structures. 3. Improved ROM at hips, pelvis and thorax. 4. Adductor strength. 5. Functional movement assessment. 6. Core stability. 7. Lumbo-pelvic control. 8. Gym-based strengthening. 9. Field-based conditioning/rehabilitation. The evidence for these interventions is reviewed.

RESULTS

The player returned to full training and match play within 41 and 50 days, respectively, and experienced no recurrence of his symptoms in follow up at 13 months.

CONCLUSION

This case report displays a nine-point conservative management strategy for OP/PBS, with non-time dependent clinical objective markers as the progression criteria in a Premier League football player.

High eccentric hip abduction strength reduces the risk of developing patellofemoral pain among novice runners initiating a self-structured running program: a 1-year observational study

STUDY DESIGN

Observational prospective cohort study with 1-year follow-up.

OBJECTIVES

To investigate the relationship between eccentric hip abduction strength and the development of patellofemoral pain (PFP) in novice runners during a self-structured running regime.

BACKGROUND

Recent research indicates that gluteal muscle weakness exists in individuals with PFP. However, current prospective research has been limited to the evaluation of isometric strength, producing inconsistent findings. Considering that hip muscles, including the gluteus maximus and medius, activate eccentrically to control hip and pelvic motion during weight-bearing activities such as running, the potential link between eccentric strength and PFP risk should be evaluated.

METHODS

Eight hundred thirty-two novice runners were included at baseline, and 629 participants were included in the final analysis. Maximal eccentric hip abduction strength was measured using a handheld dynamometer prior to initiating a self-structured running program. The diagnostic criteria to classify knee pain as PFP were based on a thorough clinical examination. Participants were followed for 12 months and training characteristics were gathered with a global positioning system.

RESULTS

Results from the unadjusted generalized linear regression model for cumulative risk at 25 and 50 km indicated differences in cumulative risk of PFP between high strength, normal strength, and low strength (P<.05), with higher strength associated with reduced risk.

CONCLUSION

Findings from this study indicate that, among novice runners, a level of peak eccentric hip abduction strength that is higher than normal may reduce the risk of PFP during the first 50 km of a self-structured running program.

Reliability of externally fixed dynamometry hamstring strength testing in elite youth football players

OBJECTIVES

To investigate inter and intra-tester reliability of an externally fixed dynamometry unilateral hamstring strength test, in the elite sports setting.

DESIGN

Reliability study.

METHODS

Sixteen, injury-free, elite male youth football players (age=16.81±0.54 years, height=180.22±5.29cm, weight 73.88±6.54kg, BMI=22.57±1.42) gave written informed consent. Unilateral maximum isometric peak hamstring force was evaluated by externally fixed dynamometry for inter-tester, intra-day and intra-tester, inter-week reliability. The test position was standardised to correlate with the terminal swing phase of the gait running cycle.

RESULTS

Inter and intra-tester values demonstrated good to high levels of reliability. The intra-class coefficient (ICC) for inter-tester, intra-day reliability was 0.87 (95% CI=0.75-0.93) with standard error of measure percentage (SEM%) 4.7 and minimal detectable change percentage (MDC%) 12.9. Intra-tester, inter-week reliability results were ICC 0.86 (95% CI, 0.74-0.93), SEM% 5.0 and MDC% 14.0.

CONCLUSIONS

This study demonstrates good to high inter and intra-tester reliability of isometric externally fixed dynamometry unilateral hamstring strength testing in the regular elite sport setting involving elite male youth football players. The intra-class coefficient in association with the low standard error of measure and minimal detectable change percentages suggest that this procedure is appropriate for clinical and academic use as well as monitoring hamstring strength in the elite sport setting.

Effect of early supervised progressive resistance training compared to unsupervised home-based exercise after fast-track total hip replacement applied to patients with preoperative functional limitations. A single-blinded randomised controlled trial

OBJECTIVE

To examine if 2 weekly sessions of supervised progressive resistance training (PRT) in combination with 5 weekly sessions of unsupervised home-based exercise is more effective than 7 weekly sessions of unsupervised home-based exercise in improving leg-extension power of the operated leg 10 weeks after total hip replacement (THR) in patients with lower pre-operative function.

METHOD

A total of 73 patients scheduled for THR were randomised (1:1) to intervention group (IG, home based exercise 5 days/week and PRT 2 days/week) or control group (CG, home based exercise 7 days/week). The primary endpoint was change in leg extension power at 10 week follow up. Secondary outcomes were isometric hip muscle strength, sit-to-stand test, stair climb test, 20 m walking speed and patient-reported outcome (HOOS).

RESULTS

Sixty-two completed the trial (85%). Leg extension power increased from baseline to the 10 week follow up in both groups; mean [95% CI] IG: 0.29 [0.13; 0.45] and CG: 0.26 [0.10; 0.42] W/kg, with no between-group difference (primary outcome) (P = 0.79). Maximal walking speed (P = 0.008) and stair climb performance (P = 0.04) improved more in the IG compared to CG, no other between-group differences existed.

CONCLUSIONS

In this trial, supervised PRT twice a week in addition to 5 weekly sessions of unsupervised exercise for 10 weeks was not superior to 7 weekly sessions of unsupervised home-based exercise for 10 weeks in improving the primary outcome, leg-extension power of the operated leg, at the primary endpoint 10 weeks after surgery in THR patients with lower pre-operative function.

TRIAL REGISTRATION

NCT01214954.

Is a sphygmomanometer a valid and reliable tool to measure the isometric strength of hip muscles? A systematic review

BACKGROUND

Muscle strength measurement is a key component of physiotherapists' assessment and is frequently used as an outcome measure. A sphygmomanometer is an instrument commonly used to measure blood pressure that can be potentially used as a tool to assess isometric muscle strength.

OBJECTIVE

To systematically review the evidence on the reliability and validity of a sphygmomanometer for measuring isometric strength of hip muscles.

METHOD

A literature search was conducted across four databases. Studies were eligible if they presented data on reliability and/or validity, used a sphygmomanometer to measure isometric muscle strength of the hip region, and were peer reviewed. The individual studies were evaluated for quality using a standardized critical appraisal tool.

RESULTS

A total of 644 articles were screened for eligibility, with five articles chosen for inclusion. The use of a sphygmomanometer to objectively assess isometric muscle strength of the hip muscles appears to be reliable with intraclass correlation coefficient values ranging from 0.66 to 0.94 in elderly and young populations. No studies were identified that have assessed the validity of a sphygmomanometer.

CONCLUSION

The sphygmomanometer appears to be reliable for assessment of isometric muscle strength around the hip joint, but further research is warranted to establish its validity.

Normative adductor squeeze tests scores in rugby

BACKGROUND

Groin pain is a common problem. Adductor squeeze tests are used to diagnose, monitor and prophylactically determine the risk of developing groin pain. This study defines normative adductor squeeze scores in professional rugby that will facilitate strength monitoring during screening.

METHODS

Using a sphygnamometer, squeeze scores were collected, at one professional rugby club as part of the pre-season screening for two seasons. Scores were collected in four positions. For all positions mean strength and 95% confidence intervals were calculated.

RESULTS

Data were collected for 81 athletes. Mean strength for adduction at 60° was 220.1 (212.2-228.1); 0° 211.1 (201.7-220.5); 90°90° 198.8 (190.0-207.7); 90°90° supported 224.9 (214.9-234.9). Backs had lower squeeze scores than forwards for 0°, 90°:90° and 90°:90° supported (p > 0.05 for all four tests); older players had lower scores, as did shorter and lighter players (p > 0.05 except for height with test 60° p = 0.048 and test 90°:90° supported p = 0.035).

CONCLUSION

This study establishes references ranges for adductor squeeze tests for normative pre-season data in non-injured rugby players. This information will enable evaluation and inform return to play judgements following adductor related injury.

Adductor canal block versus femoral nerve block for analgesia after total knee arthroplasty: a randomized, double-blind study

BACKGROUND AND OBJECTIVES

Femoral nerve block (FNB), a commonly used postoperative pain treatment after total knee arthroplasty (TKA), reduces quadriceps muscle strength essential for mobilization. In contrast, adductor canal block (ACB) is predominately a sensory nerve block. We hypothesized that ACB preserves quadriceps muscle strength as compared with FNB (primary end point) in patients after TKA. Secondary end points were effects on morphine consumption, pain, adductor muscle strength, morphine-related complications, and mobilization ability.

METHODS

We performed a double-blind, randomized, controlled study of patients scheduled for TKA with spinal anesthesia. The patients were randomized to receive either a continuous ACB or an FNB via a catheter (30-mL 0.5% ropivacaine given initially, followed by a continuous infusion of 0.2% ropivacaine, 8 mL/h for 24 hours). Muscle strength was assessed with a handheld dynamometer, and we used the percentile change from baseline for comparisons. The trial was registered at clinicaltrials.gov (Identifier: NCT01470391).

RESULTS

We enrolled 54 patients, of which 48 were analyzed. Quadriceps strength as a percentage of baseline was significantly higher in the ACB group compared with the FNB group: (median [range]) 52% [31-71] versus 18% [4-48], (95% confidence interval, 8-41; P = 0.004). There was no difference between the groups regarding morphine consumption (P = 0.94), pain at rest (P = 0.21), pain during flexion of the knee (P = 0.16), or adductor muscle strength (P = 0.39); neither was there a difference in morphine-related adverse effects or mobilization ability (P > 0.05).

CONCLUSIONS

Adductor canal block preserved quadriceps muscle strength better than FNB, without a significant difference in postoperative pain.

A randomized pilot study of a comprehensive postoperative exercise program compared with usual care following primary total hip arthroplasty in subjects less than 65 years of age: feasibility, selection of outcome measures and timing of assessment

Background

Total Hip Arthroplasty (THA) is being used more commonly in younger higher demand patients. The purpose of this randomized pilot study was to explore a) feasibility of comprehensive postoperative rehabilitation compared to usual care following primary THA in subjects <65 years, b) appropriate outcome measures including performance-based measures and c) timing of assessments.

Methods

21 subjects who underwent primary THA were randomized to receive a three-month out-patient rehabilitation program (Intervention) or usual postoperative care (Control). Subjects were assessed preoperatively, six-weeks postoperatively (Pre-intervention) and four and 12 months postoperatively (Post-intervention). Self-report measures were the Western Ontario McMaster Osteoarthritis Index (WOMAC) and Rand 36-Item Health Survey (RAND-36). Performance-based measures included lower extremity strength, walking speed and endurance, and gait laboratory assessment.

Results

Ten Control and 11 Intervention subjects with an average age of 53.4 (SD9.3) years were randomized. All Intervention subjects completed the program without adverse effects. Although no statistically significantly results were reported, four months postoperatively, Intervention subjects had clinically important differences (CID) in strength compared with Control subjects. Walking endurance, WOMAC and RAND scores improved significantly with no CID noted between groups. Ten (48%) subjects reported a ceiling effect on the WOMAC (9 (43%) subjects on Pain; 1 (5%) subject on Function). No group CID were noted in gait measures.

Conclusions

Our recommendations would be that performance-based strength measures should be considered for the primary outcome in this younger cohort. Because of the ceiling effects with WOMAC Pain, a different pain measure is indicated. Other more challenging functional performance-based tests should be considered such as a more prolonged endurance test. There is merit in one-year follow-up as strength improved after four months in both groups.

A study of the inter-rater reliability of a test battery for use in patients after total hip replacement

Objective:

To assess the within-day inter-rater reliability of a test battery of functional performance, muscle strength and leg extension power on total hip replacement patients.

Design:

A test–retest design was used.

Setting:

Orthopaedic department at a Regional Hospital in Denmark.

Subjects:

Two convenience samples of 20 total hip replacement patients were included.

Intervention:

The tests were performed three months after total hip replacement. Two raters performed test and re-test, with two hours rest in-between.

Main measures:

The test battery included: sit-to-stand performance, 20-metre maximum walking speed, stair climb performance, isometric muscle strength (hip abduction/flexion), and leg extension power. Absolute reliability was assessed with Bland Altman plots, standard error of measurement (SEM), and minimal detectable change. Relative reliability was assessed with intra-class correlation coefficient.

Results:

Systematic differences between testers were seen in tests of walking speed (0.32 seconds p = 0.03) and stair climb performance (0.18 seconds p = 0.003). In per cent of the grand mean, the standard error of measurement was 3%–10%, indicating the measurement error on a group level, and the minimal detectable change was 10%–27%, indicating the measurement error on an individual level. The intra-class correlation coefficients were above 0.80 in all tests (range 0.83–0.95).

Conclusions:

The tests showed acceptable relative and absolute inter-rater reliability on a group level, but not on an individual level (except from test of walking speed and stair climb performance). Systematic differences between testers were considered clinically irrelevant (0.3 and 0.2 seconds).

Risk factors for lower extremity injuries in elite female soccer players

BACKGROUND

The incidence of lower extremity injuries in female soccer players is high, but the risk factors for injuries are unknown.

PURPOSE

To investigate risk factors for lower extremity injuries in elite female soccer players.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Players in the Norwegian elite female soccer league (N = 12 teams) participated in baseline screening tests before the 2009 competitive soccer season. The screening included tests assessing maximal lower extremity strength, dynamic balance, knee valgus angles in a drop-jump landing, knee joint laxity, generalized joint laxity, and foot pronation. Also included was a questionnaire to collect information on demographic data, elite-level experience, and injury history. Time-loss injuries and exposure in training and matches were recorded prospectively in the subsequent soccer season using weekly text messaging. Players reporting an injury were contacted to collect data regarding injury circumstances. Univariate and multivariate regression analyses were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for ±1 standard deviation of change.

RESULTS

In total, 173 players underwent complete screening tests and registration of injuries and exposure throughout the season. A total of 171 injuries in 107 players (62%) were recorded; ligament and muscle injuries were the most frequent. Multivariate analyses showed that a greater body mass index (BMI) (OR, 1.51; 95% CI, 1.21-1.90; P = .001) was the only factor significantly associated with new lower extremity injuries. A greater BMI was associated with new thigh injuries (OR, 1.51; 95% CI, 1.08-2.11; P = .01), a lower knee valgus angle in a drop-jump landing was associated with new ankle injuries (OR, 0.64; 95% CI, 0.41-1.00; P = .04), and a previous knee injury was associated with new lower leg and foot injuries (OR, 3.57; 95% CI, 1.27-9.99; P = .02), whereas none of the factors investigated influenced the risk of new knee injuries.

CONCLUSION

A greater BMI was associated with lower extremity injuries in elite female soccer players.

CLINICAL RELEVANCE

Increased knowledge on risk factors for lower extremity injuries enables more targeted prevention strategies with the aim of reducing injury rates in female soccer players.

Eccentric and Isometric Hip Adduction Strength in Male Soccer Players With and Without Adductor-Related Groin Pain: An Assessor-Blinded Comparison

BACKGROUND

Adductor-related pain is the most common clinical finding in soccer players with groin pain and can be a long-standing problem affecting physical function and performance. Hip adductor weakness has been suggested to be associated with this clinical entity, although it has never been investigated.

PURPOSE

To investigate whether isometric and eccentric hip strength are decreased in soccer players with adductor-related groin pain compared with asymptomatic soccer controls. The hypothesis was that players with adductor-related groin pain would have lower isometric and eccentric hip adduction strength than players without adductor-related groin pain.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Male elite and subelite players from 40 teams were contacted. In total, 28 soccer players with adductor-related groin pain and 16 soccer players without adductor-related groin pain (asymptomatic controls) were included in the study. In primary analysis, the dominant legs of 21 soccer players with adductor-related groin pain (≥4 weeks duration) were compared with the dominant legs of 16 asymptomatic controls using a cross-sectional design. The mean age of the symptomatic players was 24.5 ± 2.5 years, and the mean age of the asymptomatic controls was 22.9 ± 2.4 years. Isometric hip strength (adduction, abduction, and flexion) and eccentric hip strength (adduction) were assessed with a handheld dynamometer using reliable test procedures and a blinded assessor.

RESULTS

Eccentric hip adduction strength was lower in soccer players with adductor-related groin pain in the dominant leg (n = 21) compared with asymptomatic controls (n = 16), namely 2.47 ± 0.49 versus 3.12 ± 0.43 N·m/kg, respectively (P < .001). No other hip strength differences were observed between symptomatic players and asymptomatic controls for the dominant leg (P = .35-.84).

CONCLUSION

Large eccentric hip adduction strength deficits were found in soccer players with adductor-related groin pain compared with asymptomatic soccer players, while no isometric strength differences were observed between the groups.

Test-retest reliability of innovated strength tests for hip muscles

The burden of hip muscles weakness and its relation to other impairments has been well documented. It is therefore a pre-requisite to have a reliable method for clinical assessment of hip muscles function allowing the design and implementation of a proper strengthening program. Motor-driven dynamometry has been widely accepted as the gold-standard for lower limb muscle strength assessment but is mainly related to the knee joint. Studies focusing on the hip joint are less exhaustive and somewhat discrepant with regard to optimal participants position, consequently influencing outcome measures. Thus, we aimed to develop a standardized test setup for the assessment of hip muscles strength, i.e. flexors/extensors and abductors/adductors, with improved participant stability and to define its psychometric characteristics. Eighteen participants performed unilateral isokinetic and isometric contractions of the hip muscles in the sagittal and coronal plane at two separate occasions. Peak torque and normalized peak torque were measured for each contraction. Relative and absolute measures of reliability were calculated using the intraclass correlation coefficient and standard error of measurement, respectively. Results from this study revealed higher levels of between-day reliability of isokinetic/isometric hip abduction/flexion peak torque compared to existing literature. The least reliable measures were found for hip extension and adduction, which could be explained by a less efficient stabilization technique. Our study additionally provided a first set of reference normalized data which can be used in future research.

Clinical recovery of two hip adductor longus ruptures: a case-report of a soccer player

Background

Non-operative treatment of acute hip adductor longus ruptures in athletes has been described in the literature. However, very limited information concerning the recovery of this type of injury exists. This case represented a unique possibility to study the recovery of two acute adductor longus ruptures, using novel, reliable and validated assessment methods.

Case presentation

A 22-year old male soccer player (Caucasian) sustained two subsequent acute adductor longus ruptures, one in each leg. The injuries occurred 10 months apart, and were treated non-surgically in both situations. He was evaluated using hip-strength assessments, self-report and ultrasonography until complete muscle-strength recovery of the hip adductors had occurred. The player was able to participate in a full soccer training session without experiencing pain 15 weeks after the first rupture, and 12 weeks after the second rupture. Full hip adductor muscle-strength recovery was obtained 52 weeks after the first rupture and 10 weeks after the second rupture. The adductor longus injuries, as verified by initial ultrasonography (10 days post-injury), showed evidence of a complete tendon rupture in both cases, with an almost identical imaging appearance. It was only at 6 and 10 weeks ultrasonographic follow-up that the first rupture was found to include a larger anatomical area than the second rupture.

Conclusion

From this case we can conclude that two apparently similar hip adductor longus ruptures, verified by initial ultrasonography (10 days post-injury), can have very different hip adductor strength recovery times. Assessment of adductor strength recovery may therefore in the future be a useful and important additional measure for determining when soccer players with hip adductor longus ruptures can return safely to play.

Surgery-induced changes and early recovery of hip-muscle strength, leg-press power, and functional performance after fast-track total hip arthroplasty: a prospective cohort study

BACKGROUND

By measuring very early changes in muscle strength and functional performance after fast-track total hip arthroplasty (THA), post-operative rehabilitation, introduced soon after surgery, can be designed to specifically target identified deficits.

OBJECTIVES

Firstly, to quantify changes (compared to pre-operative values) in hip muscle strength, leg-press power, and functional performance in the first week after THA, and secondly, to explore relationships between the muscle strength changes, and changes in hip pain, systemic inflammation, and thigh swelling.

DESIGN

Prospective, cohort study.

SETTING

Convenience sample of patients receiving a THA at Copenhagen University Hospital, Hvidovre, Denmark, between March and December 2011.

PARTICIPANTS

Thirty-five patients (65.9 ± 7.2 years) undergoing THA.

MAIN OUTCOME MEASURES

Hip muscle strength, leg-press power, performance-based function, and self-reported disability were determined prior to, and 2 and 8 days after, THA (Day 2 and 8, respectively). Hip pain, thigh swelling, and C-Reactive Protein were also determined.

RESULTS

Five patients were lost to follow-up. Hip muscle strength and leg press power were substantially reduced at Day 2 (range of reductions: 41-58%, P<0.001), but less pronounced at Day 8 (range of reductions: 23-31%, P<0.017). Self-reported symptoms and function (HOOS: Pain, Symptoms, and ADL) improved at Day 8 (P<0.014). Changes in hip pain, C-Reactive Protein, and thigh swelling were not related to the muscle strength and power losses.

CONCLUSIONS

Hip muscle strength and leg-press power decreased substantially in the first week after THA - especially at Day 2 - with some recovery at Day 8. The muscle strength loss and power loss were not related to changes in hip pain, systemic inflammation, or thigh swelling. In contrast, self-reported symptoms and function improved. These data on surgery-induced changes in muscle strength may help design impairment-directed, post-operative rehabilitation to be introduced soon after surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01246674.

EMG evaluation of hip adduction exercises for soccer players: implications for exercise selection in prevention and treatment of groin injuries

INTRODUCTION

Exercise programmes are used in the prevention and treatment of adductor-related groin injuries in soccer; however, there is a lack of knowledge concerning the intensity of frequently used exercises.

OBJECTIVE

Primarily to investigate muscle activity of adductor longus during six traditional and two new hip adduction exercises. Additionally, to analyse muscle activation of gluteals and abdominals.

MATERIALS AND METHODS

40 healthy male elite soccer players, training >5 h a week, participated in the study. Muscle activity using surface electromyography (sEMG) was measured bilaterally for the adductor longus during eight hip adduction strengthening exercises and peak EMG was normalised (nEMG) using an isometric maximal voluntary contraction (MVC) as reference. Furthermore, muscle activation of the gluteus medius, rectus abdominis and the external abdominal obliques was analysed during the exercises.

RESULTS

There were large differences in peak nEMG of the adductor longus between the exercises, with values ranging from 14% to 108% nEMG (p<0.0001). There was a significant difference between legs in three of the eight exercises (35-48%, p<0.0001). The peak nEMG results for the gluteals and the abdominals showed relatively low values (5-48% nEMG, p<0.001).

CONCLUSIONS

Specific hip adduction exercises can be graded by exercise intensity providing athletes and therapists with the knowledge to select appropriate exercises during different phases of prevention and treatment of groin injuries. The Copenhagen Adduction and the hip adduction with an elastic band are dynamic high-intensity exercises, which can easily be performed at any training facility and could therefore be relevant to include in future prevention and treatment programmes.

Hip- and knee-strength assessments using a hand-held dynamometer with external belt-fixation are inter-tester reliable

PURPOSE

In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt-fixation of the dynamometer may resolve this. The aim of the present study was therefore to examine the inter-tester reliability concerning strength assessments of isometric hip abduction, adduction, flexion, extension and knee-flexion strength, using HHD with external belt-fixation.

METHODS

Twenty-one healthy athletes (6 women), 30 (8.6) (mean (SD)) years of age, were included. Two physiotherapy students (1 female and 1 male) performed all the measurements after careful instruction and procedure training. Isometric hip abduction, adduction, flexion, extension, and knee-flexion strength were tested. The tester-order and hip-action order were randomised.

RESULTS

No systematic between-tester differences (bias) were observed for any of the hip or knee actions. The intra-class correlation coefficients (ICC 2.1) ranged from 0.76 to 0.95. Furthermore, standard errors of measurement in per cent (SEM %) ranged from 5 to 11 %, and minimal detectable change in per cent (MDC %) from 14 to 29 % for the different hip and knee actions.

CONCLUSION

The present study shows that isometric hip- and knee-strength measurements have acceptable inter-tester reliability at the group level, when testing strong individuals, using HHD with belt-fixation. This procedure is therefore perfectly suited for the evaluation and monitoring of strong athletes with hip, groin and hamstring injuries, some of the most common and troublesome injuries in sports.

LEVELS OF EVIDENCE

Diagnostic, Level III.

Arthroscopic partial meniscectomy in middle-aged patients with mild or no knee osteoarthritis: a protocol for a double-blind, randomized sham-controlled multi-centre trial

BACKGROUND

Arthroscopic partial meniscectomy has been shown to be of no benefit to patients with concomitant knee osteoarthritis, but the optimal treatment of a degenerative meniscus tear in patients with mild or no knee osteoarthritis is unknown. This article describes the rationale and methodology of a randomized sham-controlled trial to assess the benefit of arthroscopic partial meniscectomy of a medial meniscus tear in patients with mild or no knee osteoarthritis. The objective of the study is to test whether the benefit from arthroscopic partial meniscectomy in patients with knee pain, medial meniscus lesion and mild/no knee osteoarthritis, is greater after arthroscopic partial meniscectomy than following sham surgery.

METHODS

We will conduct a randomized controlled trial of treatment for degenerative meniscus tears in middle-aged patients (aged 35-55 years) with an MRI-verified medial meniscus lesion and mild or no knee radiographic osteoarthritis (grade 0-2 on the Kellgren & Lawrence scale). Patients will be randomized to receive either conventional arthroscopic partial meniscectomy or a sham surgery procedure. The primary outcome will be the KOOS5 derived from the 'Knee Injury and Osteoarthritis Outcome Score' at 2 years follow-up. Secondary outcomes at 2 years will include all five individual subscales of the KOOS, a global perceived effect score, the Short-Form-36 health status score, EQ-5D for economic appraisal and objective tests of muscle strength and physical function. Radiographic knee osteoarthritis will be evaluated at 5 years.

DISCUSSION

Demonstration of no additional benefit from arthroscopic partial meniscectomy on pain and function should lead to a change in clinical care of patients with a degenerative meniscus tear. The results of this study will provide empirical evidence for the potential benefit/harm of arthroscopic partial meniscectomy compared to a masked sham-therapeutics intervention.

Greater understanding of normal hip physical function may guide clinicians in providing targeted rehabilitation programmes

OBJECTIVES

This study investigated tests of hip muscle strength and functional performance. The specific objectives were to: (i) establish intra- and inter-rater reliability; (ii) compare differences between dominant and non-dominant limbs; (iii) compare agonist and antagonist muscle strength ratios; (iv) compare differences between genders; and (v) examine relationships between hip muscle strength, baseline measures and functional performance.

DESIGN

Reliability study and cross-sectional analysis of hip strength and functional performance.

METHODS

In healthy adults aged 18-50years, normalised hip muscle peak torque and functional performance were evaluated to: (i) establish intra-rater and inter-rater reliability; (ii) analyse differences between limbs, between antagonistic muscle groups and genders; and (iii) associations between strength and functional performance.

RESULTS

Excellent reliability (intra-rater ICC=0.77-0.96; inter-rater ICC=0.82-0.95) was observed. No difference existed between dominant and non-dominant limbs. Differences in strength existed between antagonistic pairs of muscles: hip abduction was greater than adduction (p<0.001) and hip ER was greater than IR (p<0.001). Men had greater ER strength (p=0.006) and hop for distance (p<0.001) than women. Strong associations were observed between measures of hip muscle strength (except hip flexion) and age, height, and functional performance.

CONCLUSIONS

Deficits in hip muscle strength or functional performance may influence hip pain. In order to provide targeted rehabilitation programmes to address patient-specific impairments, and determine when individuals are ready to return to physical activity, clinicians are increasingly utilising tests of hip strength and functional performance. This study provides a battery of reliable, clinically applicable tests which can be used for these purposes.

Reproducibility of range of motion and muscle strength measurements in patients with hip osteoarthritis - an inter-rater study

Background

Assessment of range of motion (ROM) and muscle strength is fundamental in the clinical diagnosis of hip osteoarthritis (OA) but reproducibility of these measurements has mostly involved clinicians from secondary care and has rarely reported agreement parameters. Therefore, the primary objective of the study was to determine the inter-rater reproducibility of ROM and muscle strength measurements. Furthermore, the reliability of the overall assessment of clinical hip OA was evaluated. Reporting is in accordance with proposed guidelines for the reporting of reliability and agreement studies (GRRAS).

Methods

In a university hospital, four blinded raters independently examined patients with unilateral hip OA; two hospital orthopaedists independently examined 48 (24 men) patients and two primary care chiropractors examined 61 patients (29 men). ROM was measured in degrees (deg.) with a standard two-arm goniometer and muscle strength in Newton (N) using a hand-held dynamometer. Reproducibility is reported as agreement and reliability between paired raters of the same profession. Agreement is reported as limits of agreement (LoA) and reliability is reported with intraclass correlation coefficients (ICC). Reliability of the overall assessment of clinical OA is reported as weighted kappa.

Results

Between orthopaedists, agreement for ROM ranged from LoA [-28–12 deg.] for internal rotation to [-8–13 deg.] for extension. ICC ranged between 0.53 and 0.73, highest for flexion. For muscle strength between orthopaedists, LoA ranged from [-65–47N] for external rotation to [-10 –59N] for flexion. ICC ranged between 0.52 and 0.85, highest for abduction. Between chiropractors, agreement for ROM ranged from LoA [-25–30 deg.] for internal rotation to [-13–21 deg.] for flexion. ICC ranged between 0.14 and 0.79, highest for flexion. For muscle strength between chiropractors, LoA ranged between [-80–20N] for external rotation to [-146–55N] for abduction. ICC ranged between 0.38 and 0.81, highest for flexion. Weighted kappa for the overall assessment of clinical hip OA was 0.52 between orthopaedists and 0.65 between chiropractors.

Conclusions

Reproducibility of goniometric and dynamometric measurements of ROM and muscle strength in patients with hip OA is poor between experienced orthopaedists and between experienced chiropractors. Orthopaedists and chiropractors can to a moderate degree differentiate between hips with or without osteoarthritis.

The effects of neuromuscular exercise on medial knee joint load post-arthroscopic partial medial meniscectomy: 'SCOPEX', a randomised control trial protocol

Background

Meniscectomy is a risk factor for knee osteoarthritis, with increased medial joint loading a likely contributor to the development and progression of knee osteoarthritis in this group. Therefore, post-surgical rehabilitation or interventions that reduce medial knee joint loading have the potential to reduce the risk of developing or progressing osteoarthritis. The primary purpose of this randomised, assessor-blind controlled trial is to determine the effects of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during functional tasks in people who have recently undergone a partial medial meniscectomy.

Methods/design

62 people aged 30–50 years who have undergone an arthroscopic partial medial meniscectomy within the previous 3 to 12 months will be recruited and randomly assigned to a neuromuscular exercise or control group using concealed allocation. The neuromuscular exercise group will attend 8 supervised exercise sessions with a physiotherapist and will perform 6 exercises at home, at least 3 times per week for 12 weeks. The control group will not receive the neuromuscular training program. Blinded assessment will be performed at baseline and immediately following the 12-week intervention. The primary outcomes are change in the peak external knee adduction moment measured by 3-dimensional analysis during normal paced walking and one-leg rise. Secondary outcomes include the change in peak external knee adduction moment during fast pace walking and one-leg hop and change in the knee adduction moment impulse during walking, one-leg rise and one-leg hop, knee and hip muscle strength, electromyographic muscle activation patterns, objective measures of physical function, as well as self-reported measures of physical function and symptoms and additional biomechanical parameters.

Discussion

The findings from this trial will provide evidence regarding the effect of a home-based, physiotherapist-supervised neuromuscular exercise program on medial knee joint load during various tasks in people with a partial medial meniscectomy. If shown to reduce the knee adduction moment, neuromuscular exercise has the potential to prevent the onset of osteoarthritis or slow its progression in those with early disease.

Trial Registration

Australian New Zealand Clinical Trials Registry reference: ACTRN12612000542897

Effects of weekly and fortnightly therapeutic exercise on physical function and health-related quality of life in individuals with hip osteoarthritis

BACKGROUND

Most previous studies on the effects of therapeutic exercise on osteoarthritis (OA) of the hip joint included participants with knee OA or postoperative participants. Moreover, although some systematic reviews recommend therapeutic exercise for hip OA, a consensus on the effective interventional frequency has not been reached. This study aimed to investigate the effects of therapeutic exercise performed at different frequencies on physical function and health-related quality of life in participants with hip OA.

METHODS

Individuals diagnosed with hip OA (36 women, age 42-79 years; 19 in 2009 and 17 in 2010) were recruited from the cooperating medical institutions. They were divided into two groups depending on the frequency of therapeutic exercise: fortnightly in 2009 (fortnightly group) and weekly in 2010 (weekly group). Participants in each group performed the same land-based and aquatic exercises on the same day for a total of ten sessions. Muscle strength of the lower extremity, "timed up and go" (TUG), time of one-leg standing with open eyes (TOLS), Harris Hip Score, and scores of the Medical Outcomes Survey Short Form-36 questionnaire, were measured before and after interventions.

RESULTS

The fortnightly group had no significant changes in lower-extremity muscle strength following intervention, but the strength of all muscles in the weekly group improved significantly after intervention. Further, in both groups, TUG and TOLS of the worse side of the hip joint significantly improved after interventions.

CONCLUSIONS

Weekly exercise improves muscle strength of the lower extremity and may therefore be an effective interventional technique for managing hip OA. In addition, in persons with hip OA, therapeutic exercise consisting of both land- and water-based exercises markedly improved physical function.

Hip abduction weakness in elite junior footballers is common but easy to correct quickly: a prospective sports team cohort based study

BACKGROUND

Hip abduction weakness has never been documented on a population basis as a common finding in a healthy group of athletes and would not normally be found in an elite adolescent athlete. This study aimed to show that hip abduction weakness not only occurs in this group but also is common and easy to correct with an unsupervised home based program.

METHODS

A prospective sports team cohort based study was performed with thirty elite adolescent under-17 Australian Rules Footballers in the Australian Institute of Sport/Australian Football League Under-17 training academy. The players had their hip abduction performance assessed and were then instructed in a hip abduction muscle training exercise. This was performed on a daily basis for two months and then they were reassessed.

RESULTS

The results showed 14 of 28 athletes who completed the protocol had marked weakness or a side-to-side difference of more than 25% at baseline.Two months later ten players recorded an improvement of ≥ 80% in their recorded scores. The mean muscle performance on the right side improved from 151 Newton (N) to 202 N (p<0.001) while on the left, the recorded results improved from 158 N to 223 N (p<0.001).

CONCLUSIONS

The baseline values show widespread profound deficiencies in hip abduction performance not previously reported. Very large performance increases can be achieved, unsupervised, in a short period of time to potentially allow large clinically significant gains. This assessment should be an integral part of preparticipation screening and assessed in those with lower limb injuries. This particular exercise should be used clinically and more research is needed to determine its injury prevention and performance enhancement implications.

Eccentric hip abductor weakness in patients with symptomatic external snapping hip

Symptomatic external snapping hip can be a long-standing condition affecting physical function in younger people between 15-40 years. Gluteal weakness has been suggested to be associated with the condition. The aim of this study was to investigate whether eccentric hip abduction strength is decreased in patients with external snapping hip compared with healthy matched controls, and to examine isometric hip abduction, adduction, extension, flexion, internal rotation, and external rotation in patients with external snapping hip and matched controls. Thirteen patients with external snapping hip were compared with 13 healthy matched controls in a cross-sectional study design. The mean age of the patients was 25.5 ± 3.4 years and the mean age of the controls was 25.6 ± 2.6 years. Eccentric and isometric strength were assessed with a handheld dynamometer, using reliable test procedures. Eccentric hip abduction strength was 16% lower in patients with external snapping hip compared with healthy matched controls (1.50 ± 0.47 Nm/kg versus 1.82 ± 0.48 Nm/kg, P = 0.01). No other strength differences were measured between patients and controls (P > 0.05). Eccentric hip abductor weakness was present in patients with symptomatic external snapping hip compared with healthy matched controls.

Eccentric strengthening effect of hip-adductor training with elastic bands in soccer players: a randomised controlled trial

BACKGROUND

Soccer players with weak hip-adductor muscles are at increased risk of sustaining groin injuries. Therefore, a simple hip-adductor strengthening programme for prevention of groin injuries is needed.

OBJECTIVE

We aimed to investigate the effect of an 8-week hip-adductor strengthening programme, including one hip-adduction exercise, on eccentric and isometric hip-adduction strength, using elastic bands as external load.

METHODS

Thirty-four healthy, sub-elite soccer players, mean (±SD) age of 22.1 (±3.3) years, were randomised to either training or control. During the mid-season break, the training group performed 8 weeks of supervised, progressive hip-adduction strength training using elastic bands. The participants performed two training sessions per week (weeks 1-2) with 3×15 repetition maximum loading (RM), three training sessions per week (weeks 3-6) with 3×10 RM and three training sessions per week (weeks 7-8) with 3×8 RM. Eccentric hip-adduction (EHAD), isometric hip-adduction (IHAD) and isometric hip-abduction (IHAB) strength, and the IHAD/IHAB ratio were measured assessor-blinded preintervention and postintervention, using reliable hand-held dynamometry procedures.

RESULTS

In the training group, EHAD strength increased by 30% (p<0.001). In the control group, EHAD strength increased by 17% (p<0.001), but the increase was significantly larger in the training group compared with the control group (p=0.044). No other significant between-group strength-differences in IHAD, IHAB or the IHAD/IHAB ratio existed (p>0.05).

CONCLUSIONS

8 weeks of hip-adduction strength training, using elastic bands, induce a relevant increase in eccentric hip-adduction strength in soccer players, and thus may have implications as a promising approach towards prevention of groin injuries in soccer.

Hip strength assessment using handheld dynamometry is subject to intertester bias when testers are of different sex and strength

Handheld dynamometry (HHD) is a promising tool for obtaining reliable hip strength measurements in the clinical setting, but intertester reliability has been questioned, especially in situations where testers exhibit differences in upper-extremity muscle strength (male vs female). The purpose of this study was to examine the intertester reliability concerning strength assessments of hip abduction, adduction, external and internal rotation, flexion and extension using HHD, and to test whether systematic differences in test values exist between testers of different upper-extremity strength. Fifty healthy individuals (29 women), aged 25 ± 5 years were included. Two physiotherapist students (one female, one male) of different upper-extremity strength performed the measurements. The tester order and strength test order were randomized. Intraclass correlation coefficients were used to quantify reliability, and ranged from 0.82 to 0.91 for the six strength test. The female tester systematically measured lower strength values for all isometric strength tests (P < 0.05). In hip strength assessments using HHD, systematic bias exists between testers of different sex, which is likely explained by differences in upper-extremity strength. Hence, to improve intertester reliability, the dynamometer likely needs external fixation, as this will eliminate the influence of differences in upper-extremity strength between testers.

EMG of the hip adductor muscles in six clinical examination tests

OBJECTIVES

To assess activation of muscles of hip adduction using EMG and force analysis during standard clinical tests, and compare athletes with and without a prior history of groin pain.

STUDY DESIGN

Controlled laboratory study.

PARTICIPANTS

21 male athletes from an elite junior soccer program.

MAIN OUTCOME MEASURES

Bilateral surface EMG recordings of the adductor magnus, adductor longus, gracilis and pectineus as well as a unilateral fine-wire EMG of the pectineus were made during isometric holds in six clinical examination tests. A load cell was used to measure force data.

RESULTS

Test type was a significant factor in the EMG output for all four muscles (all muscles p < 0.01). EMG activation was highest in Hips 0 or Hips 45 for adductor magnus, adductor longus and gracilis. EMG activation for pectineus was highest in Hips 90. Injury history was a significant factor in the EMG output for the adductor longus (p < 0.05), pectineus (p < 0.01) and gracilis (p < 0.01) but not adductor magnus. For force data, clinical test type was a significant factor (p < 0.01) with Hips 0 being significantly stronger than Hips 45, Hips 90 and Side lay. BMI (body mass index) was a significant factor (p < 0.01) for producing a higher force. All other factors had no significant effect on the force outputs.

CONCLUSIONS

Hip adduction strength assessment is best measured at hips 0 (which produced most force) or 45° flexion (which generally gave the highest EMG output). Muscle EMG varied significantly with clinical test position. Athletes with previous groin injury had a significant fall in some EMG outputs.

Hip abduction strength training in the clinical setting: with or without external loading?

The side-lying hip abduction exercise is one of the most commonly used exercises in rehabilitation to increase hip abduction strength, and is often performed without external loading. The aim of this study was to compare the effect of 6 weeks of side-lying hip abduction training, with and without external loading, on hip abduction strength in healthy subjects. Thirty-one healthy, physically active men and women were included in a randomised controlled trial and allocated to side-lying hip abduction training, with or without external loading. Training without external loading was performed using only the weight of the leg as resistance, whereas training with external loading was performed with a relative load corresponding to 10 repetition maximum. Hip abduction strength was measured pre- and post-intervention. Isometric and eccentric hip abduction strength of the trained leg increased after hip abduction training with external loading by 12% and 17%, respectively, (P<0.05). Likewise, isometric and eccentric hip abduction strength of the trained leg increased after hip abduction training without external loading by 11% and 23%, respectively, (P<0.001). The strength increases were not different between groups (P>0.05). Six weeks of side-lying hip abduction training, with or without external loading, increases isometric and eccentric hip abduction strength to the same extent.