Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, The Netherlands.
Arch Phys Med Rehabil. 2010 Jan;91(1):123-8. doi: 10.1016/j.apmr.2009.09.008.
Horstman AM, Gerrits KH, Beltman MJ, Koppe PA, Janssen, TW, de Haan A. Intrinsic properties of the knee extensor muscles after subacute stroke.
To characterize muscle properties of paretic lower-limb (PL) and nonparetic lower-limb (NL) knee extensors in patients with subacute stroke.
Case-control study.
Rehabilitation center research laboratory.
Patients with subacute stroke (n=14) and able-bodied age-matched control subjects (n=12).
Not applicable.
Half relaxation times (HRTs) and maximal rates of torque development (MRTDs) were assessed as indicators of contractile speed using both voluntary and electrically evoked contractions. Moreover, changes in torque were measured during a fatigue protocol (35 electrically evoked intermittent contractions; 1.5s on, 2s off) and recovery.
No differences among groups were found for normalized MRTDs during electrically evoked contractions (P=.117). However, during voluntary contractions both PLs (53% of control, P=.022) and NL (71% of control, P<.001) had significantly lower MRTD compared with control. Both PL (134% of control, P=.001) and NL (123% of control, P=.032) had significantly higher HRTs than control, indicating muscle slowing in patients with subacute stroke. PLs fatigued more and faster than control (P=.011) and both PL and NL recovered slower (P<.001).
The changes in HRTs and fatigue suggest adaptations in muscle properties toward slower, more fatigable muscle shortly after stroke. The inability to make use of contractile speed because of impaired neural activation seems the most limiting factor during the initial phase of torque development in PL. Thus, besides strengthening, muscle endurance and speed should also be addressed during rehabilitation.
描述亚急性脑卒中患者患侧（PL）和健侧（NL）下肢伸膝肌的肌肉特性。
病例对照研究。
康复中心研究实验室。
亚急性脑卒中患者（n=14）和年龄匹配的健康对照组（n=12）。
无。
采用电刺激和自主收缩两种方式评估半松弛时间（HRT）和最大扭矩发展速率（MRTD），以评估收缩速度。此外，在疲劳协议（35 次电刺激间歇性收缩；1.5s 收缩，2s 舒张）和恢复过程中测量扭矩变化。
电刺激收缩时，各组间标准化的 MRTD 无差异（P=.117）。然而，在自主收缩时，PL（比对照组低 53%，P=.022）和 NL（比对照组低 71%，P<.001）的 MRTD 明显较低。与对照组相比，PL（比对照组高 134%，P=.001）和 NL（比对照组高 123%，P=.032）的 HRT 均显著较高，提示亚急性脑卒中患者的肌肉速度减慢。PL 的疲劳速度和程度均高于对照组（P=.011），且 PL 和 NL 的恢复速度均较慢（P<.001）。
HRT 和疲劳的变化表明，肌肉特性发生了改变，向更慢、更易疲劳的肌肉方向发展，这发生在脑卒中后不久。由于神经激活受损，导致无法利用收缩速度，这似乎是 PL 初始扭矩发展阶段最具限制的因素。因此，除了加强力量外，肌肉耐力和速度也应在康复中得到重视。
