Abstract des Autors

The aim of this brief study was to investigate the effects of repeated jump testing on performance over 2 consecutive days while considering the possibility of diurnal changes. Fourteen male subjects and 14 recreationally active female subjects completed countermovement jump (CMJ) and squat jump (SJ) testing on 5 occasions (baseline [0,800], 5 minutes [0,820], 8 hours [1,600], 24 hours [0,800], and 32 hours [1,600]) over 32 hours. An additional rested baseline test was conducted on a separate day in the afternoon (1,600) to compare jump performance between morning and afternoon baseline values. Excluding small decreases in CMJ height at 24 hours (p = 0.292, Cliffʼs delta = −0.225) in male subjects and similar decreases in CMJ height at 5 minutes (p = 0.034, Cliffʼs delta = −0.245) in addition to SJ height:contraction time at 32 hours (p = 0.126, Cliffʼs delta = 0.153) in female subjects, findings generally showed no changes in jump performance over multiple assessments. Squat jump metrics may have showed small improvements between morning and afternoon baseline values in male subjects (SJ height:contraction time [ p = 0.030, Cliffʼs delta = 0.225]) and female subjects (SJ height [ p = 0.013, Cliffʼs delta = 0.173] and SJ height:contraction time [ p = 0.091, Cliffʼs delta = 0.163)]. As jump performance was largely unaffected by repeated jump testing, the present findings support the use of monitoring practices and research designs that require multiple jump assessments within acute periods (∼32 hours).