Introduction: Biathlon combines cross country skiing and rifle marksmanship, and the athletes need to carry the rifle (mass >3.5 kg) on their back during skiing. Previous research in laboratory settings have shown that physiological variables, i.e. heart rate (HR), oxygen uptake (VO2), ventilation (VE), breathing frequency (BF), respiratory exchange ratio (RER) and blood lactate concentration (BLa) increases when roller-skiing with rifle (WR) at submaximal workloads compared to roller-skiing without rifle (NR) (1, 2). Roller-skiing performance is also shown to decrease for WR compared to NR during laboratory testing (1). Purpose: The aim was to investigate the effect of rifle carriage on performance and physiological variables during a simulated biathlon roller-skiing sprint in the field.Methods: 20 well-trained tier 3 (3) biathletes (10 women, 10 men; age 22±3 years) completed two biathlon roller-skiing sprints (women 3×2km; men 3×2.5km) in the field, one WR and one NR in a randomized order, separated by 30 minutes of active rest. After each lap, the athlete stopped for 30–45 s (normal shooting time) for measurement of BLa and rating of perceived exertion (RPE, 6–20). Respiratory variables and HR were measured throughout the sprints. A two-way repeated measurements ANOVA (two conditions (WR/NR) × three laps) was used to compare performance and physiological variables between conditions. During the stops, WR and NR was compared using paired samples t-test. Wilcoxon Signed Rank test was used if data was non-normally distributed. Data are presented as mean±SD, except for RPE (presented as median (IQR)).Results: Mean roller-skiing speed for the race was 0.20 m/s slower for WR compared to NR (5.5±0.5 vs. 5.7±0.5 m/s, p<0.001). The time loss during WR was 13.5±14.6, 12.2±8.7 and 16.9±9.6 s for laps 1, 2, and 3, respectively. No difference between WR and NR in mean HR, O2, VE, BF, RER or BLa was found for any of the skiing laps (all p>0.05). However, RPE, mean VO2, VE and BF during the second stop (simulating standing shooting) was higher for WR compared to NR (RPE 18 (1) vs 17 (1), p = 0.008; VO2 40±5 vs 37±4 ml/kg/min, p=0.006; VE 99±23 vs 92±18 L/min, p=0.031; BF 52±6 vs. 48±4 breaths/min, p=0.005) with no difference in the duration of the stop (p>0.05). Conclusion: Unlike previous laboratory studies, this field-based study demonstrates that respiratory variables, HR and BLa were similar for WR and NR during roller-skiing, despite the higher skiing speed for NR during all the three laps. However, respiratory variables and RPE were higher during the second stop for WR, which may impact shooting performance. To replicate competition demands, biathletes are advised to carry their rifle during high-intensity training sessions that include shooting.
1. Jonsson Kårström et. al (2019) doi: 10.3389/fphys.2019.015192. Stöggl et. al (2015) doi: 10.1249/mss.00000000000004383. McKay et. al (2022) doi: 10.1123/ijspp.2021-0451
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