The reliability and validity of different jump-test performance metrics for fatigue monitoring in amateur boxing

Jump testing has become widespread practice in sport science for monitoring athletes' fatigue.The purposes of this study were to determine whether the number of trials performed influenced the reliability of jump-test performance metrics, as well as establish the construct validity of these jump-test performance metrics for monitoring fatigue in amateur boxing.After institutional ethical approval, seven novice (stature 1.81 0.08 m, mass 82.7 12.4 kg, age 20.9 0.8 years, training <6 months) and seven experienced amateur boxers (stature 1.74 0.12 m, mass 71.3 13.5 kg, age 22.0 3.4 years, training >18 months) participated.All boxers completed familiarisation and three experimental trials, involving a standardised warmup and eight jump-tests.These jumptests included countermovement and squat jumps, performed bilaterally and unilaterally as well as vertically and horizontally.For each jump-test, 12 performance metrics were calculated using the maximum, mean or median height or distance, from combinations of the four attempts performed per jump-test, with and without one initial practice.Trial two also involved 3 x 2 min rounds of sparring to induce fatigue.Reliability was calculated for novice and experienced boxers separately using typical error between trials one and two, which ranged from 1.5 to 19 cm across the performance metrics.Construct validity was determined by a 2 x 2 within and between group ANOVA (novice v experienced, trial two v three).Only unilateral vertical squat jump height could discriminate experienced from novice boxers after a fatiguing sparring bout.Jump height of experienced boxers was lower than novices by 2.0 0.2 cm (p = 0.01, 95% CI [1.1, 3.0] cm) when using the mean of two attempts after one practice.As typical error was 1.3 cm, results suggest that this jump-test and performance metric appear reliable and valid for monitoring fatigue in amateur boxing.