Biathlon is an endurance sport combining rifle shooting and intermittent cross-country skiing while carrying a rifle (minimum weight 3.5 kg). Previous studies have shown that the skiing component explains 60% of overall biathlon performance (1) and that rifle carriage affects different physiological responses such as blood lactate, oxygen uptake (VO2) and heart rate during skiing (2, 3). However, the effects of rifle carriage on skiing performance and variables such as maximal VO2 (VO2max), lactate threshold, efficiency of movement and anaerobic energy contribution have not yet been investigated.METHODS:Seventeen biathletes (9 females, 8 males; age 23.0 (3.3) years, VO2max 59.8 (7.3) mL/kg/min), competing at a national and/or international level, and completing approximately three biathlon training sessions/week with the rifle on the back, performed a submaximal incremental test and a 900–1000-m maximal time-trial (TT) using treadmill roller-skiing (gear 3 skating technique) on two occasions separated by at least 48 hours. One condition involved carrying the rifle on the back (WR) and the other no rifle (NR), with the order randomized. The VO2 and skiing speed at 4 mmol/L of blood lactate (VO2@4mmol and speed@4mmol, respectively), gross efficiency (GE), metabolic aerobic (MRae) and anaerobic (MRan) rates, and VO2max were determined. RESULTS:Submaximal VO2 at all levels and GE (16.7 (0.9) vs 16.5 (1.1) %, p<0.05) were higher for WR compared to NR, while speed@4mmol (11.3 (1.5) vs 11.7 (1.5) km/h, p<0.05) and MRan (27.3 (6.7) vs 30.5 (7.6) kJ/min, p<0.01) was lower. There were no differences in VO2@4mmol or MRae between the two conditions. The mean speed during the TT was higher for NR compared to WR (16.5 (1.5) vs 15.5 (1.4) km/h, p<0.001), but there was no difference in VO2max. Mean speed during the TT was correlated to speed@4mmol (WR: r=0.810, p<0.001; NR: r=0.659, p<0.01), GE (WR: r=0.691; NR r=0.529, both p<0.05) and VO2max (WR: r=0.514; NR: r=0.526, both p<0.05). Speed@4mmol together with MRan explained more than 80% of performance in the TT (WR 83.7%, NR 81.5%). There was no difference between male and female biathletes in response to rifle carriage, although the relative mass of the rifle was higher for the females (5.6 (0.4) vs 5.0 (0.4) % of body mass, p<0.01).CONCLUSION:According to this study, the most important variables for skiing speed in biathlon seem to be the speed at lactate threshold combined with the metabolic anaerobic rate, both of which were lower for skiing with the rifle compared to without. In addition, GE was related to biathlon performance and was also affected by rifle carriage. Thus, to improve skiing performance in biathlon, improving speed at the lactate threshold, anaerobic energy delivery and GE while carrying the rifle are recommended.
2019.