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.
Shane J. Gore, Brendan M. Marshall, Andrew D. Franklyn-Miller, Eanna C. Falvey and Kieran A. Moran
Brendan M. Marshall, Andrew D. Franklyn-Miller, Kieran A. Moran, Enda A. King, Siobhán C. Strike and Éanna C Falvey
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.
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.
40 recreational field-sports players diagnosed with AGP.
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.
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).
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.