Effect of Exercise Intensity on Biathlon Standing Shooting Performance and Rifle Movement during Outdoor Roller Skiing.

PURPOSE: To investigate the effect of exercise intensity on standing shooting performance and related technical variables in elite biathletes performing roller skiing and live shooting outdoors. METHODS: Nineteen male biathletes performed two 5-shot series in the following order of exercise intensity: rest, low (%heart rate max 73 ± 4; blood lactate 1.5 ± 0.3 mmol·L-1), moderate (84 ± 3; 2.4 ± 0.6), 'race-pace' (90 ± 2; 4.5 ± 0.8), and 'final-lap' (i.e., near-maximal effort: 93 ± 3; 8.7 ± 1.4). Except for rest, each shooting series was preceded by 1 km roller ski skating on a competition track. Rifle movements and triggering were determined from marker-based motion capture and accelerometer data. The primary variables were shooting outcome (hit/miss) and distance from center (dC), determined from an electronic target, and barrel velocity. Mediation analyses for shooting outcome and dC were conducted with barrel velocity (mean over last 0.25 s before triggering) as mediator and intensity as predictor. RESULTS: Exercise intensity increased the likelihood of miss at 'race' (odds ratio (OR) 2.2, 95% CI 1.0-4.7) and 'final-lap' (OR 2.8, 95% CI 1.4-5.8) intensities compared to rest, with no meaningful differences between rest, low, and moderate intensities. Further, intensity affected dC (~32 ± 15 mm at rest, low, and moderate, 36 ± 20 mm at 'race', and 40 ± 23 mm at 'final-lap'; p < 0.001). Barrel velocity was a partial mediator of both shooting outcome and dC, explaining some, but not all, of the effect of intensity. CONCLUSIONS: Exercise intensity seems to have a clear negative effect on standing shooting performance in biathlon, which is partially explained by an increase in barrel velocity. Deteriorating effects were mainly seen at the two highest (race-like) intensities. Accordingly, for specificity reasons, more shooting practice should perhaps be performed at higher, competition-like exercise intensities than what is currently the norm.

Highly Trained Biathletes With a Fast-Start Pacing Pattern Improve Time-Trial Skiing Performance by Pacing More Evenly.

PURPOSE: In sprint biathlon, a J-shaped pacing pattern is commonly used. We investigated whether biathletes with a fast-start pacing pattern increase time-trial skiing and shooting performance by pacing more evenly. METHODS: Thirty-eight highly trained biathletes (∼21 y, 27 men) performed an individual 7.5 (3 × 2.5 km for women) or 10-km (3 × 3.3 km for men) time trial on roller skis with a self-selected pacing strategy (day 1). Prone (after lap 1) and standing shooting (after lap 2) stages were performed using paper targets. Based on their pacing strategy in the first time trial (ratio between the initial ∼800-m segment pace on lap 1 and average ∼800-m segment pace on laps 1-3), participants were divided into an intervention group with the fastest starting pace (INT, n = 20) or a control group with a more conservative starting pace (CON, n = 18). On day 2, INT was instructed to reduce their starting pace, while CON was instructed to maintain their day 1 strategy. RESULTS: INT increased their overall time-trial performance more than CON from day 1 to day 2  (mean ± 95% CI; 1.5% ± 0.7% vs 0.0% ± 0.9%, P = .02). From day 1 to day 2, INT reduced their starting pace (5.0% ± 1.5%, P < .01), with reduced ratings of perceived exertion during lap 1 (P < .05). For CON, no change was found for starting pace (-0.8% ± 1.2%) or ratings of perceived exertion between days. No differences were found for shooting performance for either group. CONCLUSION: Highly trained biathletes with a pronounced fast-start pattern improve skiing performance without any change in shooting performance by pacing more evenly.

Contribution from cross-country skiing, start time and shooting components to the overall and isolated biathlon pursuit race performance.

PURPOSE: Biathlon is an Olympic sport combining 3-5 laps of cross-country skiing with rifle shooting, alternating between the prone and standing shooting positions between laps. The individual distance and the sprint are extensively examined whereas the pursuit, with start times based on the sprint results, is unexplored. Therefore, the current study aimed to investigate the contribution from start time, cross-country skiing time, penalty time, shooting time and range time to the overall and isolated performance in biathlon World Cup pursuit races. METHODS: 38 and 37 stepwise linear regression analyses for each of the races were performed, including 112 and 128 unique athletes where 20 and 13 athletes had more than 20 results within top 30 during the seasons 2011/2012-2015/2016 in men and women, respectively. RESULTS: Start time (i.e. sprint race performance) together with penalty time, explained ~80% of the performance-variance (R2) in overall pursuit performance in most races (p<0.01). For isolated pursuit performance, penalty time was the most important component, explaining >54% of the performance-variance in the majority of races, followed by course time (accumulated R2 = .91-.92) and shooting time (accumulated R2 = .98-.99) (p<0.01). Approximately the same rankings of factors were found when comparing standardized coefficients and correlation coefficients of the independent variables included in the regression. CONCLUSION: Start time (i.e. sprint race performance) is the most important component for overall pursuit performance in biathlon, whereas shooting performance followed by course time are the most important components for the isolated pursuit race performance.

The Interval-Based Physiological and Mechanical Demands of Cross-Country Ski Training.

PURPOSE: To investigate fluctuations in speed, work rate, and heart rate (HR) when cross-country ski skating across varying terrains at different endurance-training intensities. METHODS: Seven male junior Norwegian skiers performed maximal-speed (Vmax) tests in both flat and uphill terrains. Thereafter, 5-km sessions at low (LIT), moderate (MIT), and high intensity (HIT) were performed based on their own perception of intensity while monitored by a global navigation satellite system with integrated barometry and accompanying HR monitor. RESULTS: Speed, HR, and rating of perceived exertion gradually increased from LIT to MIT and HIT, both for the total course and in flat and uphill terrains (all P < .05). Uphill work rates (214 [24] W, 298 [27] W, and 350 [54] W for LIT, MIT, and HIT, respectively) and the corresponding percentage of maximal HR (79.2% [6.1]%, 88.3% [2.4]%, and 91.0% [1.7]%) were higher than in flat terrain (159 [16] W, 206 [19] W, and 233 [72] W vs 72.3% [6.3]%, 83.2% [2.3]%, and 87.4% [2.0]% for LIT, MIT, and HIT, respectively) (all P < .01). In general, ∼13% point lower utilization of maximal work rate was reached in uphill than in flat terrain at all intensities (all P < .01). CONCLUSIONS: Cross-country ski training across varying terrains is clearly interval based in terms of speed, external work rate, and metabolic intensity for all endurance-training intensities. Although work rate and HR were highest in uphill terrain at all intensities, the utilization of maximal work rate was higher in flat terrain. This demonstrates the large potential for generating external work rate when uphill skiing and the corresponding downregulation of effort due to the metabolic limitations.

Analysis of a Biathlon Sprint Competition and Associated Laboratory Determinants of Performance.

Biathlon is an Olympic winter-sport where cross-country (XC) skiing in the skating technique is combined with rifle shooting. In the biathlon sprint competition for men, three laps of 3.3-km are interspersed with a 5-shot shooting sequence in the prone and standing position. Our purpose was to investigate the contribution from overall XC skiing performance, the performance in different terrain sections and shooting performance to the overall biathlon sprint race performance, as well as the relationship to laboratory-measured capacities obtained during treadmill roller ski skating. Eleven elite male biathletes were tracked by a Global Positioning System (GPS) device and a heart rate (HR) monitor during an international 10-km biathlon sprint competition. Within a period of 6 weeks prior to the competition, physiological responses, and performance during submaximal and maximal treadmill roller skiing were measured. Stepwise multiple regression analysis revealed that XC skiing time, shooting performance, shooting time and range time explained 84, 14, 1.8, and 0.2% of the overall sprint race performance (all p < 0.01). Time in uphill, varied, and downhill terrains were all significantly correlated to the total XC skiing time (r = 0.95, 0.82, 0.72, respectively, all p < 0.05). Percent of maximal HR (HRmax) and rating of perceived exertion (RPE) during submaximal roller skiing, and time-to-exhaustion during incremental roller skiing correlated significantly with overall biathlon sprint race performance and overall XC skiing time (r = 0.64-0.95, all p < 0.05). In conclusion, XC skiing performance provided greatest impact on biathlon sprint performance, with most of the variance determined by XC skiing performance in the uphill terrain sections. Furthermore, the ability to roller ski with a low RPE and %HRmax during submaximal speeds, as well as time-to-exhaustion during incremental roller skiing significantly predicted biathlon performance. Such laboratory-derived measures may therefore be validly used to distinguish biathletes of different performance levels and to track progress of their XC skiing capacity.

The Contribution From Cross-Country Skiing and Shooting Variables on Performance-Level and Sex Differences in Biathlon World Cup Individual Races.

Biathlon is an Olympic winter sport that combines rifle shooting and cross-country skiing in various race formats. In the individual distance (15 km for women and 20 km for men), athletes compete over 5 laps of skiing with shooting between each 2 laps (ie, 4 shootings). The aim of the current study was to compare total race time differences, as well as the contribution from cross-country skiing and shooting variables to this difference, between biathletes of different performance levels and sexes in individual races in the Biathlon World Cup. Based on the publicly available race reports, the authors compared these factors between top-10 results (G1-10) and results within rank 21-30 (G21-30), as well as the corresponding sex differences. G21-30 among men/women were on average 4%/6% behind G1-10 in total race time, in which course time accounted for 42%/54% of the overall performance difference, followed by 53%/44% explained by penalty time caused by shooting performance (ie, the number of hits). The remaining 2-3% was explained by differences in shooting time and range time. Women G1-10 were on average 15% slower in skiing speed than men G1-10, which accounted for 92% of the overall performance difference between sexes. In total, among G1-10, men shot on average 15 s faster than women, and total penalty time was 18 s shorter. In conclusion, course time and penalty time contributed approximately equally to the performance-level differences, whereas course time explained above 90% of the sex differences in individual World Cup biathlon races.

Comparison of the Effects of Performance Level and Sex on Sprint Performance in the Biathlon World Cup.

Biathlon is an Olympic sport combining cross-country skiing with the skating technique and rifle shooting. The sprint (7.5 km for women and 10 km for men) includes 2 shootings between 3 laps of skiing. The aims of the current study were to compare biathletes of different performance levels and sex on total race time and performance-determining factors of sprint races in the biathlon World Cup. The top-10 performers (G1-10) and results in ranks 21-30 (G21-30) in 47 sprint races during the 2011-12 to 2015-16 World Cup seasons were compared regarding total race time, course time, shooting time, range time, shooting performance (rate of hits), and penalty time. G21-30 men and women were on average 3-5% behind G1-10 in total race time, in which course time accounted for 59-65% of the overall performance difference, followed by 31-35% explained by penalty time. The remainder (ie, 4-6%) was explained by differences in shooting time and range time. The G1-10 women exhibited on average 12% slower speeds than the G1-10 men, and course time accounted for 93% of the total time difference of 13% between sexes. The average total hit rates were 92-93% among the G1-10 and 85% among the G21-30 in both sexes. In total, men shot on average 6 s faster than women. Course time is the most differentiating factor for overall biathlon performance between performance levels and sex in World Cup races. No sex difference in shooting performance was found.

A Comparison of Frontal Theta Activity During Shooting among Biathletes and Cross-Country Skiers before and after Vigorous Exercise.

BACKGROUND: Previous studies using electroencephalography (EEG) to monitor brain activity have linked higher frontal theta activity to more focused attention and superior performance in goal-directed precision tasks. In biathlon, shooting performance requires focused attention after high-intensity cross-country skiing. PURPOSE: To compare biathletes (serving as experts) and cross-country skiers (novices) and examine the effect of vigorous exercise on frontal theta activity during shooting. METHODS: EEG frontal theta (4-7 Hz) activity was compared between nine biathletes and eight cross-country skiers at comparable skiing performance levels who fired 100 shots on a 5-m indoor shooting range in quiescent condition followed by 20 shots after each of five 6-min high-intensity roller skiing sessions in the skating technique on a treadmill. RESULTS: Biathletes hit 80±14% and 81±10% before and after the roller skiing sessions, respectively. For the cross-country skiers these values were significantly lower than for the biathletes and amounted to 39±13% and 44±11% (p<0.01). Biathletes had on average 6% higher frontal theta activity during shooting as compared to cross-country skiers (F1,15 = 4.82, p = 0.044), but no significant effect of vigorous exercise on frontal theta activity in either of the two groups were found (F1,15 = 0.14, p = 0.72). CONCLUSIONS: Biathletes had significantly higher frontal theta activity than cross-country skiers during shooting, indicating higher focused attention in biathletes. Vigorous exercise did not decrease shooting performance or frontal theta activity during shooting in biathletes and cross-country skiers.