Kellawan J Mikhail, Tschakovsky Michael E
School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.
PLoS One. 2014 Apr 3;9(4):e93481. doi: 10.1371/journal.pone.0093481. eCollection 2014.
No non-invasive test exists for forearm exercise that allows identification of power-time relationship parameters (W', critical power) and thereby identification of the heavy-severe exercise intensity boundary and scaling of aerobic metabolic exercise intensity. The aim of this study was to develop a maximal effort handgrip exercise test to estimate forearm critical force (fCF; force analog of power) and establish its repeatability and validity. Ten healthy males (20-43 years) completed two maximal effort rhythmic handgrip exercise tests (repeated maximal voluntary contractions (MVC); 1 s contraction-2 s relaxation for 600 s) on separate days. Exercise intensity was quantified via peak contraction force and contraction impulse. There was no systematic difference between test 1 and 2 for fCF(peak) force (p = 0.11) or fCF(impulse) (p = 0.76). Typical error was small for both fCF(peak force) (15.3 N, 5.5%) and fCF(impulse) (15.7 N ⋅ s, 6.8%), and test re-test correlations were strong (fCF(peak force), r = 0.91, ICC = 0.94, p<0.01; fCF(impulse), r = 0.92, ICC = 0.95, p<0.01). Seven of ten subjects also completed time-to-exhaustion tests (TTE) at target contraction force equal to 10%<fCF(peak force) and 10%>fCF(peak force). TTE predicted by W' showed good agreement with actual TTE during the TTE tests (r = 0.97, ICC = 0.97, P<0.01; typical error 0.98 min, 12%; regression fit slope = 0.99 and y intercept not different from 0, p = 0.31). MVC did not predict fCF(peak force) (p = 0.37), fCF(impulse) (p = 0.49) or W' (p = 0.15). In conclusion, the poor relationship between MVC and fCF or W' illustrates the serious limitation of MVC in identifying metabolism-based exercise intensity zones. The maximal effort handgrip exercise test provides repeatable and valid estimates of fCF and should be used to normalize forearm aerobic metabolic exercise intensity instead of MVC.
目前尚无用于前臂运动的无创测试方法，能够识别功率-时间关系参数（W'，临界功率），从而无法确定重度-极重度运动强度边界以及对有氧代谢运动强度进行标度。本研究的目的是开发一种最大用力握力运动测试，以估计前臂临界力（fCF；功率的力模拟量），并确定其重复性和有效性。10名健康男性（20 - 43岁）在不同日期完成了两次最大用力有节奏握力运动测试（重复最大自主收缩（MVC）；1秒收缩 - 2秒放松，持续600秒）。运动强度通过峰值收缩力和收缩冲量进行量化。fCF（峰值）力（p = 0.11）或fCF（冲量）（p = 0.76）在测试1和测试2之间没有系统差异。fCF（峰值力）（15.3 N，5.5%）和fCF（冲量）（15.7 N·s，6.8%）的典型误差都很小，测试 - 重测相关性很强（fCF（峰值力），r = 0.91，ICC = 0.94，p<0.01；fCF（冲量），r = 0.92，ICC = 0.95，p<0.01）。10名受试者中的7名还在目标收缩力等于10%<fCF（峰值力）和10%>fCF（峰值力）的情况下完成了力竭时间测试（TTE）。在TTE测试期间，由W'预测的TTE与实际TTE显示出良好的一致性（r = 0.97，ICC = 0.97，P<0.01；典型误差0.98分钟，12%；回归拟合斜率 = 0.99且y轴截距与0无差异，p = 0.31）。MVC无法预测fCF（峰值力）（p = 0.37）、fCF（冲量）（p = 0.49）或W'（p = 0.15）。总之，MVC与fCF或W'之间的不良关系说明了MVC在识别基于代谢的运动强度区域方面的严重局限性。最大用力握力运动测试为fCF提供了可重复且有效的估计值，应使用该测试来规范前臂有氧代谢运动强度，而不是MVC。
