The Single Hop for Distance Test: Reviewing the Methodology to Measure Maximum and Repeated Performance.

Abstract

The single hop for distance (SHD) and Limb Symmetry Index are often used to assess readiness for returning to sport postinjury. However, the sensitivity of SHD Limb Symmetry Index for detecting functional abnormalities is questionable due to the methodological inconsistencies in the literature. The common methods use few repetitions; lacking consideration of repeated maximum performance, or the effect of fatigue (or failed attempts) on repeated maximum performance, required for sport. The objectives were to review the SHD for evaluating repeated maximum performance, and the effect of failed attempts on consistency of performance, in a healthy population of sportspersons. A quantitative, nonexperimental, same-subject, repeated-measures design with 15 healthy Cardiff University students. Participants performed the SHD up to 30 times on each limb, with standardized rests. A failed attempt, if the landing was not controlled, was noted but distance not recorded. Participants stopped if 3 consecutive distances decreased, or 30 repetitions were achieved. Average hop distance increased with each repetition. Only the 28th to 30th hops were between the maximum average value and 1 SD below. With failed repetitions included, the maximum average hop was at repetition 21 with more results falling between the maximum and 1 SD below, demonstrating more consistency in repeated performance. The number of failed repetitions had a trend to increase over time; whether subjects overreach in attempt to achieve maximum performance, or whether due to fatigue is unknown. Maximum performance of SHD is not achieved until multiple repetitions have been conducted. Repeated maximum performance does not drop-off until over 21 repetitions have been conducted. Consistency of repeated maximum performance varies depending on whether failed attempts are included in the analysis. Further investigation into the reasons for failed attempts is required to improve clinical decision making for return to sport postinjury.