Author(s): BALDAUF, L., SIENER, M., DEBERTSHÄUSER, J., WILKE, J., Institution: UNIVERSITÄT BAYREUTH, Country: GERMANY, Abstract-ID: 2572

INTRODUCTION:
Besides negatively affecting motor performance, sleep deprivation (SD) has also been shown to impair cognitive function. Specifically, acute SD disrupts attention, inhibitory control, working memory, and mental flexibility. In most open skill sports, athletes are required to adapt their movements to a multitude of unpredictable stimuli within split seconds, drawing on both motor and perceptive-cognitive skills. It therefore seems plausible that SD compromises the safety of high-risk actions such as jump landings. This study examined the effect of acute SD on motor cognitive performance and lower extremity mechanics during unplanned single leg landings.
METHODS:
Twenty recreational athletes (22±2 years, 177±8 cm, 73±10 kg) completed (a) 24 hours of supervised SD and (b) 24 hours without SD in randomized order and with a washout phase of 7 days. Before and after both conditions, participants performed the D2 test of attention, a series of motor cognitive tasks (reaction speed, stop signal task, reactive agility test), and 20 counter-movement jumps with unplanned single leg landings (visual cue with required landing leg during flight phase) onto a force plate. Peak ground reaction force (pGRF) was calculated from force plate data. Lower limb joint angles and moments at initial contact (IC) as well as peak ground reaction forces (pGRF) during landing were calculated using 3D motion capturing. Carryover effects were preliminarily checked using point-biserial correlation (sequence and outcomes). Differences (time*condition) were examined using linear mixed models adjusted for time (pre/post) and repeated measures within participants via random intercepts and slopes for time.
RESULTS:
SD caused more D2 omission errors (ß=7.1, p<0.01) and higher reaction times (ß= 23 ms, p=0.01). Stop-signal task and reactive agility performance were unaffected (p>.05). Regarding landing biomechanics, peak ground reaction force was not different between conditions (p=0.75). At IC, SD evoked higher knee extension (β = +5.1°. p<0.01), tibial external rotation (β = +7.0°, p<0.01), ankle dorsiflexion (β = +2.5°, p<0.01), and ankle eversion (β = +5.5°, p<0.01) angles. Additionally, we observed higher knee abduction (β = +2.6 Nm, p<0.01) and ankle dorsiflexion (β = +9,9 Nm, p<0.01) moments. At peak ground reaction force, hip flexion was reduced (β = −2.3°, p = −0.22), while knee abduction moments were increased (β = +14.1 Nm, p<0.01).
CONCLUSION:
Acute SD impairs markers of cognitive function (attention and reaction time) as well as unplanned jump landing mechanics. Particularly, the combination of increased ankle eversion, knee extension, tibial external rotation angles and increased knee abduction moments seem to be reflective of a substantially increased risk for anterior cruciate ligament rupture. Future research may aim to a) extend our findings to reduced sleep duration as opposed to complete deprivation and b) evaluate the impact of recovery strategies.