Ebersole K T, Housh T J, Johnson G O, Evetovich T K, Smith D B, Perry S R
Center for Youth Fitness and Sports Research, University of Nebraska-Lincoln, 68588-0229, USA.
Eur J Appl Physiol Occup Physiol. 1998 Aug;78(3):264-9. doi: 10.1007/s004210050418.
The purpose of this investigation was to examine the effect of leg flexion angle on the relationship between mechanomyographic (MMG) amplitude and isometric torque production. Adult males (n = 9) performed isometric muscle actions of the leg extensors at 25, 50, 75, and 100 percent maximal voluntary contraction (%MVC) on a calibrated CYBEX 6000 dynamometer at 25, 50, and 75 degrees below full extension. A piezoelectric MMG recording device was placed over the mid-portion of the rectus femoris. At 25 degrees of leg flexion, the MMG amplitude increased to 100%MVC. At 50 and 75 degrees of leg flexion, however, MMG amplitude increased to 75%MVC, and then did not change significantly (P > 0.05) between 75 and 100%MVC. These findings indicate that the MMG amplitude-isometric torque relationship is joint angle specific and may be the result of leg flexion angle differences in: (1) muscle stiffness, or (2) motor unit activation strategies.
本研究的目的是检验腿部屈曲角度对肌动图（MMG）幅度与等长扭矩产生之间关系的影响。成年男性（n = 9）在CYBEX 6000校准测力计上，于完全伸展以下25度、50度和75度时，以最大自主收缩（%MVC）的25%、50%、75%和100%进行腿部伸肌的等长肌肉动作。一个压电MMG记录装置放置在股直肌中部。在腿部屈曲25度时，MMG幅度增加到100%MVC。然而，在腿部屈曲50度和75度时，MMG幅度增加到75%MVC，然后在75%和100%MVC之间没有显著变化（P>0.05）。这些发现表明，MMG幅度-等长扭矩关系是特定于关节角度的，可能是由于腿部屈曲角度在以下方面的差异所致：（1）肌肉刚度，或（2）运动单位激活策略。
