Int J Sports Physiol Perform. 2022 Mar 17;17(7):1030-1036. doi: 10.1123/ijspp.2021-0021. Print 2022 Jul 1.
To investigate the validity of a treadmill speed incline conversion chart using physiological and subjective measures.
Two groups of experienced runners (SLOW and FAST: divided based on their easy run pace) ran 6 speed incline combinations for 5 minutes each. Stages were equivalent according to the HillRunner.com chart, and stage order was randomized. Due to limitations of the chart, SLOW (n = 11) ran at inclines up to 4%, while FAST (n = 22) ran at inclines up 10%. Oxygen consumption (VO2), respiratory exchange ratio, heart rate, blood lactate, overall rating of perceived exertion (RPE), and leg RPE were measured for each stage. VO2 was compared against the VO2 predicted by the American College of Sports Medicine (ACSM) equation (ACSM VO2). Repeated-measures analysis of variance was used to detect differences between stages and inclines, and Hedges g was used as a measure of effect size.
Pooled results (0%-4%, N = 33) showed no incline effect on VO2, respiratory exchange ratio, heart rate, blood lactate, or RPE (P > .05; ηp2=.198), validating the chart at these inclines. At or above 6%, meaningful and significant increases occur in VO2 (g > 0.9, P < .05), with increases in heart rate, blood lactate, and leg RPE at higher inclines. ACSM VO2 underestimated oxygen consumption at all inclines up to 8% (P < .05) but not at 10% (45.9 [4.0] vs 46.7 [2.4] mL·kg-1·min-1; P = .186).
The HillRunner.com chart is only valid at or below 4%. At higher inclines, supposedly equivalent stages result in increased exercise intensity. ACSM VO2 underestimates VO2 in trained runners at inclines up to 8%.
研究跑步机速度坡度转换图表的有效性，使用生理和主观测量方法。
两组经验丰富的跑步者（慢组和快组：根据轻松跑的速度划分）以 5 分钟为一组，分别进行 6 种速度坡度组合的跑步。根据 HillRunner.com 图表，各阶段是等效的，阶段顺序是随机的。由于图表的限制，慢组（n=11）的坡度最高可达 4%，而快组（n=22）的坡度最高可达 10%。每个阶段都测量了氧气消耗（VO2）、呼吸交换比、心率、血乳酸、总体感知用力程度（RPE）和腿部 RPE。将 VO2 与美国运动医学学院（ACSM）方程（ACSM VO2）预测的 VO2 进行比较。使用重复测量方差分析来检测阶段和坡度之间的差异，并用 Hedges g 作为效应大小的度量。
汇总结果（0%-4%，n=33）表明，在这些坡度下，VO2、呼吸交换比、心率、血乳酸或 RPE 没有坡度效应（P>.05；ηp2=.198），验证了图表的有效性。在 6%及以上，VO2 会出现有意义且显著的增加（g>0.9，P<.05），随着坡度的增加，心率、血乳酸和腿部 RPE 也会增加。在所有坡度下，ACSM VO2 都低估了氧气消耗（P<.05），但在 10%时则没有（45.9[4.0]与 46.7[2.4] mL·kg-1·min-1；P=.186）。
HillRunner.com 图表仅在 4%及以下有效。在更高的坡度下，理论上等效的阶段会导致运动强度增加。在坡度达到 8%之前，ACSM VO2 会低估训练有素的跑步者的 VO2。
