School of Sport, Health and Exercise Sciences, Bangor University, George Building, Gwynedd, UK.
J Rheumatol. 2010 Feb;37(2):282-4. doi: 10.3899/jrheum.090584. Epub 2009 Dec 15.
To explore muscle-specific force (force per physiological cross-sectional area, or PCSA) and muscle activation in cachectic patients with rheumatoid arthritis (RA).
In 14 muscle-wasted patients with RA and age and sex matched healthy controls, vastus lateralis (VL) force and voluntary activation capacity were assessed during maximal isometric contractions with electromyography and superimposed electrical stimulations. VL PCSA was determined from ultrasound measures of fiber fascicle length (Lf), pennation angle, and volume, together with assessments of body composition by dual energy x-ray absorptiometry and objective physical function.
Although patients with RA had reduced physical function, lower muscle mass, and VL volume relative to controls, there were no differences in muscle-specific force and activation. PCSA, force, and pennation angle tended to be lower in RA, with no differences in Lf.
Muscle-specific force and activation are not compromised and thus are unlikely to contribute to reduced function in cachectic patients with RA.
探讨类风湿关节炎（RA）消瘦患者的肌肉特异性力量（每生理横截面积的力量，或 PCSA）和肌肉激活情况。
在 14 名肌肉消瘦的 RA 患者和年龄、性别匹配的健康对照者中，通过肌电图和叠加电刺激评估最大等长收缩时的股外侧肌（VL）力量和自愿激活能力。通过超声测量纤维束长度（Lf）、肌纤维角和体积来确定 VL 的 PCSA，并通过双能 X 射线吸收法和客观身体功能评估身体成分。
尽管 RA 患者的身体功能降低，肌肉质量和 VL 体积均低于对照组，但肌肉特异性力量和激活没有差异。RA 患者的 PCSA、力量和肌纤维角趋于较低，但 Lf 无差异。
肌肉特异性力量和激活没有受到损害，因此不太可能导致 RA 消瘦患者功能下降。
