Can a Single-Leg Squat Provide Insight Into Movement Control and Loading During Dynamic Sporting Actions in Patients With Athletic Groin Pain?

CONTEXT: Chronic athletic groin pain (AGP) is common in field sports and has been associated with abnormal movement control and loading of the hip and pelvis during play. A single-leg squat (SLS) is commonly used by clinicians to assess movement control, but whether it can provide insight into control during more dynamic sporting movements in AGP patients is unclear. OBJECTIVE: To determine the relationships between biomechanical measures in an SLS and the same measures in a single-leg drop landing, single-leg hurdle hop, and a cutting maneuver in AGP patients. DESIGN: Cross-sectional study. SETTING: Biomechanics laboratory. PATIENTS: 40 recreational field-sports players diagnosed with AGP. INTERVENTION: A biomechanical analysis of each individual's SLS, drop landing, hurdle hop, and cut was undertaken. MAIN OUTCOME MEASURES: Hip, knee, and pelvis angular displacement and hip and knee peak moments. Pearson product-moment correlations were used to examine relationships between SLS measures and equivalent measures in the other movements. RESULTS: There were no significant correlations between any hip or pelvis measure in the SLS with the same measures in the drop landing, hurdle hop, or cut (r = .03-.43, P > .05). Knee frontal- and transverse-plane angular displacement were related in the SLS and drop landing only, while knee moments were related in the SLS, drop-landing, and hurdle hop (r = .50-.67, P < .05). CONCLUSION: For AGP patients, an SLS did not provide meaningful insight into hip and pelvis control or loading during sporting movements that are associated with injury development. The usefulness of an SLS test in the assessment of movement control and loading in AGP patients is thus limited. The SLS provided moderate insight into knee control while landing and therefore may be of use in the examination of knee-injury risk.

The Number of Trials Required to Obtain a Representative Movement Pattern During a Hurdle Hop Exercise.

When reporting a subject's mean movement pattern, it is important to ensure that reported values are representative of the subject's typical movement. While previous studies have used the mean of 3 trials, scientific justification of this number is lacking. One approach is to determine statistically how many trials are required to achieve a representative mean. This study compared 4 methods of calculating the number of trials required in a hopping movement to achieve a representative mean. Fifteen males completed 15 trials of a lateral hurdle hop. Range of motion at the trunk, pelvis, hip, knee, and ankle, in addition to peak moments for the latter 3 joints were examined. The number of trials required was computed using a peak intraclass correlation coefficient method, sequential analysis with a bandwidth of acceptable variance in the mean, and a novel method based on the standard error of measurement (SEMind). The number of trials required across all variables ranged from 2 to 12 depending on method, joint, and anatomical plane. The authors advocate the SEMind method as it demonstrated fewer limitations than the other methods. Using the SEMind, the required number of trials for a representative mean during the lateral hurdle hop is 6.

Biomechanical factors associated with time to complete a change of direction cutting maneuver.

Cutting ability is an important aspect of many team sports, however, the biomechanical determinants of cutting performance are not well understood. This study aimed to address this issue by identifying the kinetic and kinematic factors correlated with the time to complete a cutting maneuver. In addition, an analysis of the test-retest reliability of all biomechanical measures was performed. Fifteen (n = 15) elite multidirectional sports players (Gaelic hurling) were recruited, and a 3-dimensional motion capture analysis of a 75° cut was undertaken. The factors associated with cutting time were determined using bivariate Pearson's correlations. Intraclass correlation coefficients (ICCs) were used to examine the test-retest reliability of biomechanical measures. Five biomechanical factors were associated with cutting time (2.28 ± 0.11 seconds): peak ankle power (r = 0.77), peak ankle plantar flexor moment (r = 0.65), range of pelvis lateral tilt (r = -0.54), maximum thorax lateral rotation angle (r = 0.51), and total ground contact time (r = -0.48). Intraclass correlation coefficient scores for these 5 factors, and indeed for the majority of the other biomechanical measures, ranged from good to excellent (ICC >0.60). Explosive force production about the ankle, pelvic control during single-limb support, and torso rotation toward the desired direction of travel were all key factors associated with cutting time. These findings should assist in the development of more effective training programs aimed at improving similar cutting performances. In addition, test-retest reliability scores were generally strong, therefore, motion capture techniques seem well placed to further investigate the determinants of cutting ability.

A new functional outcome assessment tool for military musculoskeletal rehabilitation: a pilot validation study.

OBJECTIVE: To examine the construct and concurrent validity of a new occupational military outcome measure (the Functional Activity Assessment [FAA]). DESIGN: A validation study. SETTING: British Defence rehabilitation facilities. PARTICIPANTS: A total of 141 service personnel who attended a musculoskeletal injury assessment clinic. METHODOLOGY: The association among the Short Form 36 (SF-36), Physical Workload Questionnaire, and the FAA was examined. Agreement and correlation with an actual medical category also was examined. MAIN OUTCOME MEASURES: FAA, SF-36 and Physical Workload Questionnaire scores. RESULTS: The FAA was significantly correlated with heavy physical workload and all SF-36 subscale and component scores, in line with predictions. The regression model retained 3 variables that accounted for 49% of the variation in FAA, most of which was accounted for by the role-physical subscale score of the SF-36. The FAA was well correlated with actual medical category. CONCLUSIONS: The FAA is a valid measure of physical health in relation to physical workload.