Mechanical demands and pacing profile adopted by elite mountain bikers during different cross-country events / Demandas mecânicas e perfil de ritmo adotado por ciclistas de montanha de elite durante diferentes eventos do cross-country

ABSTRACT Different competitive environments appears to affect the physical demands during the sports competitions. Thus, the aim of this study was to report the mechanical demand and pacing behaviour of twelve male elite mountain bikers on cross-country short track (XCC) and cross-country Olympic (XCO). During both competition, total race time, speed, power output (PO) and cadence (CA) were recorded. As the race time in the XCC is shorter (21.0 ± 0.5 vs 84.0 ± 3.0 min; p<0.01), the average speed (26.6 ± 0.6 vs 17.8 ± 0.6 km/h; p<0.01), PO (365.0 ± 26.7 vs 301.0 ± 26.2 watts; p<0.01) and CA (81.2 ± 4.7 vs 77.4 ± 4.3 rev∙min−1; p=0.01) were higher than the XCO. While a variable pacing was adopted during XCC, a positive profile was adopted in XCO. In addition, athletes adopted a more conservative starting pace during XCC (below average race speed) but a faster start during XCO (above average race speed). These findings demonstrated that mechanical parameters and pacing profile adopted by cyclists are different between XCC and XCO. Therefore, mountain bikers and coaches must develop specific strategy and training methods in order to obtain success in each competition.

RESUMO Diferentes ambientes competitivos parecem afetar as demandas físicas durante as competições esportivas. Assim, o objetivo deste estudo foi reportar as demandas mecânicas e o comportamento do pacing de doze homens ciclistas de montanha da categoria elite durante o cross-country de pista curta (XCC) e o cross-country Olímpico (XCO). Durante ambas as competições, o tempo total de corrida, velocidade, potência (PO) e cadência (CA) foram gravados. Como o tempo de prova do XCC é menor (21,0±0,5 vs 84,0±3,0 min; p<0,01), a velocidade média (26,6±0,6 vs 17,8±0,6 km/h; p<0,01), PO (365,0±26,7 vs 301,0±26,2 watts; p<0,01) e CA (81,2±4,7 vs 77,4±4,3 rev∙min−1; p=0,01) foram maiores que no XCO. Enquanto um ritmo variável foi adotado no XCC, um perfil positivo foi adotado no XCO. Além disso, os atletas adotaram um ritmo inicial mais conservador durante o XCC (abaixo da velocidade média da prova), mas um início mais rápido durante o XCO (velocidade acima da média da prova). Esses achados demonstraram que os parâmetros mecânicos e o ritmo adotados pelos ciclistas são diferentes entre o XCC e XCO. Portanto, ciclistas e treinadores devem desenvolver estratégias e métodos de treinamento específicos para obter sucesso em cada competição.

The relative peak power output of amateur mountain bikers is inversely correlated with body fat but not with fat-free mass

Abstract Aims: To evaluate whether body mass (BM) and body composition may influence mountain bike cycling performance. Methods: Forty male amateur mountain bikers attended the laboratory on two non-consecutive days. At the first visit, anthropometric measures (height, BM, body fat [BF], fat-free mass [FFM] and body mass index [BMI]) and familiarization to incremental cycling test were performed. On the second visit, cyclists performed again the incremental cycling test to measure peak power output (PPO), peak power output relative to BM (PPO-BM), and time to exhaustion (TE), which were posteriorly correlated with BM and anthropometric measures. Results: A low and moderate significant correlation were observed between TE and BM (p<0.01; r=0.40) and FFM (p<0.01; r=0.56). Moderate significant correlation was found between PPO and BM (p<0.01; r=0.45), BMI (p=0.03; r=0.35) and strong with FFM (p<0.01; r=0.59). Also, PPO-BM significantly correlated with BM (p=0.04; r=-0.31), BMI (p=0.02; r=-0.35) and BF (p<0.01; r=-0.55). No other significant correlations were observed. Conclusion: Considering PPO-BM as mainly performance variable, BM and BF can be a determining factor in mountain biking performance but FFM did not.

Ischemic preconditioning delays the time of exhaustion in cycling performance during the early but not in the late phase

Aims: To investigate the early and late ischemic preconditioning (IPC) effect on the trained cyclists' performance during incremental cycling test until exhaustion. Methods: Twenty-one male cyclists allocated to an IPC (2 x 5-min of blood flow occlusion at 50 mm Hg above systolic pressure followed + 5-min of deflation), SHAM (2 x 5-min at 20 mm Hg) or control (CON; no occlusion) interventions, performed three incremental cycling test (ICT) until exhaustion on separate days. The ICT were conducted pre interventions (baseline), 5-min and 24-h after interventions. The heart rate (HR) and power output (PO) were recorded during all ICT. Results: The IPC group increased ICT performance (4.4 ± 4.0 %; effect size (ES) = 0.27) 5-min post intervention, accompanied by HR mean reduction, compared to baseline (p < 0.05). However, there were no changes in SHAM (2.2 ± 4.2%; ES = 0.07) and CON (2.9 ± 5.0%; ES = 0.06) groups. In 24-h post intervention, SHAM (0.2 ± 4.7%; ES = 0.02) and CON (-1.0 ±1.6; ES = 0.03) maintained (p > 0.05) and IPC group decreased the performance (-4.6 ± 3.6 %; ES = 0.16) compared to 5-min post intervention (p < 0.05), but all groups were similar to baseline (p > 0.05). There were no difference (p > 0.05) among groups for PO peak, HR and ICT performance in all moments (baseline, 5-min and 24-h post intervention). Conclusion: The IPC increases early but not late incremental cycling test performance.(AU)