Effects of 10min vs. 20min passive rest after warm-up on 100m freestyle time-trial performance: A randomized crossover study.
OBJECTIVE
The aim of this study was to compare the effect of 10min vs. 20min passive rest post warm-up on performance in a 100m freestyle time-trial.


METHODS
Randomized crossover.


METHODS
Eleven competitive male swimmers performed two experimental trials on different days, consisting of 100m freestyle time-trials following 10min or 20min passive rest after a standard 1200m warm-up. Performance (time-trial), biomechanical (stroke length, stroke frequency, stroke index, propelling efficiency), physiological (blood lactate concentrations, heart rate, core and tympanic temperature), and psychophysiological (perceived effort) variables were assessed during both trials.


RESULTS
Time-trial performance was faster after 10min as opposed to 20min passive rest (58.41±1.99s vs. 59.06±1.86, p<0.01). This was supported by strong effect sizes (d=0.99) and the qualitative indication of "likely" positive effects. Heart rate before the time-trial was also higher after 10min passive rest (89±12bpm vs. 82±13bpm; p<0.01). Furthermore, net core temperature and oxygen uptake values before the time-trial were substantially lower after 20min passive rest.


CONCLUSIONS
These data suggest that the 10min post warm-up passive rest enhances 100m freestyle performance when compared to a 20min period. An improvement that appears to be mediated by the combined effects of a shorter post warm-up period on core temperature, heart rate and oxygen uptake.
University of Beira Interior, Department of Sport Sciences, Portugal; Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, Portugal.
Henrique P
HP
Neiva
University of Beira Interior, Department of Sport Sciences, Portugal; Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, Portugal.
Mário C
MC
Marques
Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, Portugal; National Institute of Education, Nanyang Technological University, Singapore.
Tiago M
TM
Barbosa
Department of Health Sciences, Public University of Navarre, Spain. Electronic address: mikel.izquierdo@gmail.com.
Mikel
M
Izquierdo
Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, Portugal; University Institute of Maia, ISMAI, Portugal.
João L
JL
Viana
University of Beira Interior, Department of Sport Sciences, Portugal; Research Center in Sport Sciences, Health Sciences and Human Development, CIDESD, Portugal.
Daniel A
DA
Marinho
D000293:Adolescent; D054874:Athletic Performance / Q000502:physiology*; D001831:Body Temperature; D018592:Cross-Over Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D011897:Random Allocation; D012146:Rest / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D013997:Time Factors; D063996:Warm-Up Exercise / Q000502:physiology*; D055815:Young Adult
D019344:Lactic Acid
Heart rate; Pre-exercise; Sports performance; Swimming; Temperature