1Department of Kinesiology, Recreation and Sport Studies, The University of Tennessee, Knoxville, TN; 2Department of Kinesiology, Health, and Physical Education, Biola University, La Mirada, CA.
Med Sci Sports Exerc. 2016 Feb;48(2):260-6. doi: 10.1249/MSS.0000000000000759.
Although effects of workload and cadence on sagittal plane knee biomechanics in cycling have been widely studied, few studies have examined their impact on the frontal plane.
The purpose of this study was to investigate the effects of different workloads and cadences on knee sagittal and frontal plane biomechanics.
Eighteen healthy participants (age, 55.7 ± 11.0 yr) volunteered for this study. A motion analysis system and a custom instrumented pedal were used to collect five cycles of three-dimensional kinematics (240 Hz) and pedal reaction force (PRF, 1200 Hz) during 2 min of cycling in each of eight testing conditions, including five workload conditions of 0.5, 1, 1.5, 2, and 2.5 kg at 60 rpm, and three cadence conditions of 70, 80, and 90 rpm with 1-kg workload. Two one-way repeated measures analyses of variance were used to examine the influence of cadence and workload on selected variables (P < 0.05).
Increased workloads with constant rpm caused an increased peak knee abduction moment from 5.82 to 14.36 N · m and peak knee extension moment from 11.61 to 37.16 N · m. Increased workloads also significantly increased peak medial and vertical PRF. Increased cadences at the constant workload had no effects on peak knee abduction moment but caused increased peak anterior and vertical PRF and peak knee flexion moment.
The findings of this study indicate that increasing workload at constant cadence significantly increased peak knee abduction moment. Further study may be needed to demonstrate the efficacy of appropriate levels of workload and cadence in knee osteoarthritis and other populations with knee problems.
尽管已有广泛研究考察了工作负荷和踏频对自行车骑行中矢状面膝关节生物力学的影响，但鲜有研究关注其对额状面的影响。
本研究旨在调查不同工作负荷和踏频对膝关节矢状面和额状面生物力学的影响。
18 名健康参与者（年龄，55.7±11.0 岁）自愿参加了本研究。使用运动分析系统和定制的测力脚踏板，在 8 种测试条件下，每种条件下均采集 2 分钟骑行时的 5 个周期的三维运动学（240 Hz）和脚踏反作用力（PRF，1200 Hz）数据，包括 5 种工作负荷条件（0.5、1、1.5、2 和 2.5 kg，转速为 60 rpm）和 3 种踏频条件（70、80 和 90 rpm，工作负荷为 1 kg）。采用 2 种单向重复测量方差分析，考察踏频和工作负荷对选定变量的影响（P＜0.05）。
恒定转速下增加工作负荷会导致膝关节外展峰值力矩从 5.82 N·m 增加到 14.36 N·m，膝关节伸展峰值力矩从 11.61 N·m 增加到 37.16 N·m。增加工作负荷还显著增加了膝关节内收和垂直方向 PRF 的峰值。在恒定工作负荷下增加踏频对膝关节外展峰值力矩没有影响，但会导致膝关节前向和垂直方向 PRF 峰值以及膝关节屈曲峰值力矩增加。
本研究结果表明，在恒定踏频下增加工作负荷会显著增加膝关节外展峰值力矩。可能需要进一步研究来验证适当的工作负荷和踏频水平在膝关节骨关节炎和其他膝关节有问题的人群中的疗效。
