ENERGY-COST OF RIFLE CARRIAGE IN BIATHLON SKIING

Purpose: Since biathlon racing involves cross-country skiing while car rying a minimum weight 3.5-kg rifle, energy cost for rifle carriage co uld be significant to race outcome. The purposes of this study were to : 1) compare physiological measurements of biathletes roller skiing wi th and without rifle carriage, 2) compare energy cost of rifle carriag e between women and men. 3) examine the relationship of cycle length a nd cycle rare to energy cost of rifle carriage, and 3) compare physiol ogical measurements to calculated estimates of power requirements of r ifle carriage. Methods: We examined metabolic cost of rifle carriage d uring inclined roller ski-skating. National Team Biathletes (7 W, 8 M) performed treadmill roller ski-skating (2.46, 2.68, and 2.91 m.s(-1), 8% incline, 5-min stages) with and without a 3.65 kg rifle. Results: For W, HR, (V) over dot O-2, and (V) over dot (E), during carriage wer e higher at all speeds, LA was higher at the fastest speed (P < 0.05). For M, (V) over dot O-2 and (V) over dot (E) were higher at all speed s, HR and LA were higher at 2.68 and 2.91 m.s(-1) (P < 0.05). Rifle ma ss as percent of body mass was different between W and M (6.6 +/- 0.7% vs 5.0 +/- 0.3%, P < 0.05). Percent increase in (V) over dot O-2 (2.1 % and 1.3% per kg load; for W and M, respectively) was not different t han rifle mass as percent body wt. Cycle length was related to increas ed (V) over dot O-2 and LA during rifle carriage for W (r = -0.59 and -0.70 to -0.85), and to LA for M (r = -0.66 to -0.83). Conclusion: The large range in cost between individuals (0.2 +/- 0.08 and 0.19 +/- 0. 17 L.min(-1); for W & M, respectively) suggests that individual econom ies for load carriage can be improved.