Validity and Reliability of an on-Court Fitness Test for Assessing and Monitoring Aerobic Fitness in Squash

Current on-court assessments of aerobic fitness in squash are not designed to yield a wealth of physiological data. Moreover, tests may require complex computer equipment or involve simulated racket strokes, which are difficult to standardize at high intensities. This study investigated the validity and reliability of a squash-specific fitness test which can yield both a standalone performance score, as well as pertinent physiological markers such as VO2max, the lactate turnpoint and oxygen cost, in a sport-specific environment. Eight national squash players completed 3 tests in a counterbalanced order: an incremental laboratory treadmill test (LAB) and 2 on-court fitness tests (STs) that involved repeated shuttle runs at increasing speeds. VO2max during ST was agreeable with LAB (typical error [TE] = 3.3 ml[middle dot]kg-1[middle dot]min-1, r = 0.79). The mean bias between LAB and ST was 2.5 ml[middle dot]kg-1[middle dot]min-1. There were no differences in maximum heart rate, postexercise blood lactate concentration, or end of test rating of perceived exertion between LAB and ST (p > 0.05). The ST was highly reliable, with 74 (10) laps completed in ST1 and 75 (12) laps in ST2 (mean bias = 1 lap, TE = 3 laps, r = 0.97). Physiological markers were also reliable, including VO2max, (TE = 1.5 ml[middle dot]kg-1[middle dot]min-1, r = 0.95), the lap number at 4 mMol-1 (TE = 4 laps, r = 0.77), and average VO2 across the first 4 stages (TE = 0.94 ml[middle dot]kg-1[middle dot]min-1, r = 0.95). We observed good agreement between LAB and ST for assessing VO2max and between both on-court trials for assessing test performance and selected physiological markers. Consequently, we recommend this test for monitoring training adaptations and prescribing individualized training in elite squash players.