Barrett Andrew M S, Maunder Ed
Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand.
School of Cardiovascular and Metabolic Health, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
Eur J Appl Physiol. 2025 Apr 29. doi: 10.1007/s00421-025-05792-4.
To investigate the impact of prolonged running on speed at the moderate-to-heavy intensity transition, and whether increased eccentric load modifies exercise-induced shifts in the moderate-to-heavy intensity transition.
Twelve endurance-trained runners (4 females, 8 males, peak oxygen uptake 51.5 mL kg min in females and 56.1 mL kg min in males) participated. Following trials to assess speed at the first ventilatory threshold (VT) on a 0% gradient and -10% gradient, participants completed two trials: (i) level trial (LVL): 120-min of running at 0% gradient and (ii) downhill trial (DH): 120-min of running with 90-min at 0% gradient and 6 × 5-min intervals at -10% gradient (DH). Running was conducted at 90% of VT speed for respective gradients. Speed at VT on 0% gradient, perceived leg muscle soreness, and maximal voluntary isometric knee extensor torque were assessed pre- and post-prolonged exercise.
An effect of time was observed for speed at VT (∆-6.2 ± 3.6% in LVL and ∆-7.6 ± 3.2% in DH, P < 0.001), with no effect of condition (LVL vs. DH, P = 0.382), or time × condition interaction (P = 0.295). Reduced metabolic energy expenditure (metabolic power) significantly contributed to the reduced speed at VT in both trials (P < 0.001), whereas changes in running economy (energetic efficiency) did not (P = 0.228).
Prolonged moderate-intensity running reduced speed at the moderate-to-heavy intensity transition, but this was not exacerbated by increased eccentric load. Reduced speed at the moderate-to-heavy intensity transition following prolonged running was primarily attributed to decreased metabolic power.
探讨长时间跑步对中高强度转换速度的影响，以及增加离心负荷是否会改变运动引起的中高强度转换变化。
12名耐力训练的跑步者（4名女性，8名男性，女性最大摄氧量为51.5 mL·kg⁻¹·min⁻¹，男性为56.1 mL·kg⁻¹·min⁻¹）参与研究。在0%坡度和-10%坡度下进行评估第一通气阈值（VT）时速度的试验后，参与者完成两项试验：（i）平地试验（LVL）：在0%坡度下跑步120分钟；（ii）下坡试验（DH）：在0%坡度下跑步90分钟，然后在-10%坡度下进行6次5分钟的间歇跑（DH）。各坡度的跑步均以VT速度的90%进行。在长时间运动前后评估0%坡度下VT时的速度、腿部肌肉酸痛感和最大自主等长膝关节伸肌扭矩。
观察到VT时速度存在时间效应（LVL中变化为-6.2±3.6%，DH中变化为-7.6±3.2%，P<0.001），条件（LVL与DH，P = 0.382）或时间×条件交互作用无影响（P = 0.295）。代谢能量消耗（代谢功率）降低在两项试验中均显著导致VT时速度降低（P<0.001），而跑步经济性（能量效率）的变化则不然（P = 0.228）。
长时间中等强度跑步会降低中高强度转换时的速度，但增加离心负荷并不会加剧这种情况。长时间跑步后中高强度转换时速度降低主要归因于代谢功率下降。
