The effects of restricted energy and fluid intake on simulated amateur boxing performance

This study examined the effects of serial reductions in energy and fluid in take on two simulated boxing performances separated by 2 days recovery. Eig ht amateur boxers (age: 23.6 +/- 3.2 years; height 275 +/- 5 cm; body mass [BM] 73.3 +/- 8.3 kg [Mean +/- SD]) performed two simulated boxing bouts (B B) under normal (N-trial) and restricted (R-trial) diets in a counterbalanc ed design over 5 days. The trials were separated by a 9-day period of norma l dietary behavior (X-trial). BM was recorded on days 1, 3, and 5 of each t rial. Simulated bouts of three, 3-min rounds with I-min recovery were compl eted on days 3 (BB 1) and 5 (BB2) of each 5-day trial. Punching force (N) w as recorded from 8 sets of 7 punches by a purpose-built boxing ergometer. H eart rate (f(C)) was monitored continuously (PE3000 Polar Sports Tester, Ke mpele, Finland), and blood lactate (BLa) and glucose (BG) were determined 4 -min post-performance (2300 StaPlus, YSI, Ohio). Energy and fluid intakes w ere significantly lower in the R-trial (p < .05). Body mass was maintained during the N-trial but fell 396 (p < .05) during the R-trial. There were no significant differences in end-of-bout f(C) or post-bout BG, but BLa was h igher in the N- than the R-trial (p < .05). R-trial punching forces were 3. 2% and 4.6% lower, respectively, compared to the corresponding N-trial bout s, but the differences did not reach statistical significance. These result s suggest that energy and fluid restrictions in weight-governed sports do n ot always lead to a significant decrease in performance, but because of the small sample size and big variations in individual performances, these fin dings should be interpreted with care.