Author(s): GALLAGHER, C., GAINTATZIS, A., LAMB, E., MCDONALD, M., PULLINGER, S.A., EDWARDS, B.J., Institution: LIVERPOOL JOHN MOORES UNIVERSITY, Country: UNITED KINGDOM, Abstract-ID: 1282

INTRODUCTION:
We investigated the effects of partial sleep deprivation (3 h for two consecutive nights, retiring at 03:30 and waking at 06:30h) on the thermoregulatory responses during a nap at 13:00h and the effect on submaximal weightlifting at 17:00.
METHODS:
Eight resistance trained males (22.8±2.1 years; 177.8±5.9 cm; 82.8±12.2 kg) participated in this study. Prior to the experimental protocol, one repetition max (1RM) for bench press and back squat, normative habitual sleep and food intake were recorded. Three familiarisation sessions were completed by all participants prior to testing. All conditions were separated by 7 days with trial order counterbalanced. Participants completed three experimental conditions which all required the participant to follow two consecutive nights of partial sleep deprivation prior to the testing day. Actimetry was used to monitor sleep and protocol compliance over these two nights. On the third day at 13:00h participants either reclined: 1) at 45 degrees in a hospital bed for 60-min remaining awake and able to read in ambient lighting of 250 Lux (PSR0), 2) in a supine position for 30min in complete darkness and attempt to sleep (PSR30), 3) in a supine position for 60 min in complete darkness and attempt to sleep (PSR60). During the testing session at 13:00h, rectal and skin temperature variables (7-sites) were monitored. At 17:00h participants completed three repetitions of left-and right-hand grip strength, followed by an active warm up and dynamic stretching. Three repetitions at 40, 60 and 80% of the individuals 1RM value, for bench press and back squat were then undertaken. MuscleLab linear encoders were attached perpendicular to the Olympic bar to record performance variables (average power, average velocity, peak velocity, and displacement).
RESULTS:
Data were analysed using a general linear model with repeated measures. No significant main effect was reported for conditions for all MuscleLab variables, for both bench press and back squat. There was a significant main effect for RPE breathing values for bench press (P=0.046), with greater mean values in the PSR0 condition compared to both PSR30 and PSR60. A significant main effect for load was identified across all Musclelab variables and RPE, whereby perceived exertion increased with greater load on the bar. We report a significant effect for retiring time (Fell asleep) for actimetry variables, with an earlier retiring time on the second night of partial sleep deprivation (P=0.041). No significant effect was reported for absolute and relative Trec, however there was a significant main effect of condition (P<0.001; ES=0.952; Power=1.00) for time point of temperature gradient (Trec–Tskin).
CONCLUSION:
In summary, heat-loss mechanisms during a nap are greater at 30 than 60 min, although this did not translate to an improvement in submaximal performance.