Hop performance and leg muscle power in athletes: Reliability of a test battery

Objectives: To measure the absolute and relative reliability and the smallest real difference (SRD) in three commonly used hop tests, two leg-power tests and the single-leg squat jump. Design: Methodological study. Setting: Clinical setting. Participants: Fourteen healthy athletes (seven women and seven men) were evaluated in a standardized test-retest design. Main outcome measures: The Intra-class correlation coefficient (ICC2.1), Standard Error of Measurement (SEM) and SRD were calculated for the vertical jump, one-leg hop for distance, side-hop, single-leg squat jump and knee-flexion and knee-extension power tests. Results: All tests showed good to excellent ICC (0.84-0.98). The SEM (%) ranged between 3.4 and 11.1 for the four hop tests and between 8.1 and 12.4 for the leg-power tests. The SRD (%) for the hop tests ranged between 9.3 and 30.7 and for the three power tests between 22.4 and 34.3. Conclusions: The absolute reliability of this test protocol showed good to excellent ICC values and measurement errors of approximately 10%. This instrument can be recommended for determining function in terms of power in healthy athletes or late in the rehabilitation process. The tests' methodological errors must be considered and caution should be taken regarding the standardization procedure during testing. (C) 2014 Elsevier Ltd. All rights reserved.