Horstman Astrid M, Beltman Marijke J, Gerrits Karin H, Koppe Peter, Janssen Thomas W, Elich Peter, de Haan Arnold
Research Institute MOVE, Faculty of Human Movement Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
Clin Physiol Funct Imaging. 2008 Jul;28(4):251-61. doi: 10.1111/j.1475-097X.2008.00802.x. Epub 2008 Jul 1.
The objective of this study was to assess the nature of muscle weakness in both legs after stroke compared with able-bodied control individuals and to examine whether there is a relationship between the degree of muscle weakness and coactivation of knee extensors and flexors as well as voluntary activation capacity of knee extensors of both paretic and non-paretic legs and indices of functional performance. Maximal voluntary isometric torques of knee extensors (MVCe) and flexors (MVCf) were determined in 14 patients (bilaterally) and 12 able-bodied controls. Simultaneous measurements were made of torque and surface EMG from agonist and antagonist muscles. Coactivation was calculated. Supramaximal triplets were evoked with electrical stimulation to estimate maximal torque capacity and degree of voluntary activation of knee extensors. MVCs, activation and coactivation parameters were correlated to scores of seven functional performance tests. MVCe, MVCf and voluntary activation were lower in paretic lower limb (PL) compared with both non-paretic lower limb (NL) and control. Besides, all these parameters of NL were also lower than control. Electrically evoked torque capacity of knee extensors of PL was about 60% of both NL and control, which were not significantly different from each other. Strong significant correlations between strength, as well as voluntary activation, and functional performance were found. Coactivation did not correlate well with functional performance. Thus, whereas for NL activation failure can explain weakness, for PL both activation failure and reduced intrinsic torque capacity are responsible for the severe weakness. Activation capacity and muscle strength correlated strongly to functional performance, while coactivation did not.
本研究的目的是评估中风后双腿肌肉无力的性质，并与身体健全的对照个体进行比较，同时研究肌肉无力程度与膝关节伸肌和屈肌的共同激活、患侧和非患侧腿部膝关节伸肌的自主激活能力以及功能表现指标之间是否存在关联。对14例患者（双侧）和12名身体健全的对照者测定了膝关节伸肌（MVCe）和屈肌（MVCf）的最大自主等长扭矩。同时测量了主动肌和拮抗肌的扭矩和表面肌电图。计算共同激活情况。通过电刺激诱发超强三联波，以估计膝关节伸肌的最大扭矩能力和自主激活程度。将MVC、激活和共同激活参数与七项功能表现测试的得分进行相关性分析。与非患侧下肢（NL）和对照相比，患侧下肢（PL）的MVCe、MVCf和自主激活较低。此外，NL的所有这些参数也低于对照。PL膝关节伸肌的电诱发扭矩能力约为NL和对照的60%，两者之间无显著差异。发现力量、自主激活与功能表现之间存在强显著相关性。共同激活与功能表现的相关性不佳。因此，对于NL，激活失败可以解释肌肉无力，而对于PL，激活失败和内在扭矩能力降低均导致严重的肌肉无力。激活能力和肌肉力量与功能表现密切相关，而共同激活则不然。
