Department of Physical Therapy, University of British Columbia, Vancouver, Canada.
J Cardiopulm Rehabil Prev. 2011 Mar-Apr;31(2):120-4. doi: 10.1097/HCR.0b013e3181f68ae4.
Midthigh intramuscular fat (IF), a feature of reduced muscle quality, is an important predictor of self-reported mobility loss in the elderly. This study compared measures of muscle strength, mass, IF, and mobility in patients with chronic obstructive pulmonary disease (COPD) and healthy subjects. Associations between measures of muscle strength, mass, IF, and mobility were explored.
Knee extensor muscle strength was assessed with an isokinetic dynamometer. Cross-sectional area and IF of the thigh muscles were measured with computerized tomography. Mobility was assessed with the repetitive sit-to-stand, self-selected gait speed, and 6-minute walk tests.
Patients with COPD (n = 21, age 71.3 ± 8.1 years, and a percentage predicted force expiratory volume in 1 second of 47.2 ± 12.9) and 21 healthy subjects matched for age (67.4 ± 8.6 years), gender, and body mass participated in the study. Patients with COPD showed reduced average knee extensor strength (29%, P = .016) cross-sectional area of the thigh muscles (17%, P = .007) and mobility measures (~23%, P ≤ .001). Knee extensor and flexor IF was 2-folds greater in people with COPD (P ≤ .005). Measures of knee extensor muscle strength, mass, and IF were not associated with mobility measures.
Compared with healthy controls, patients with moderate to severe COPD show marked deficits in muscle strength, mass, quality, and mobility. More studies with larger sample size are required to elucidate whether any of these muscle deficits can explain mobility impairments in COPD.
股中部肌内脂肪（IF）是肌肉质量降低的一个特征，是老年人自述活动能力丧失的一个重要预测指标。本研究比较了慢性阻塞性肺疾病（COPD）患者和健康受试者的肌肉力量、质量、IF 和活动能力的测量值。探讨了肌肉力量、质量、IF 和活动能力测量值之间的相关性。
使用等速测力计评估膝关节伸肌力量。使用计算机断层扫描测量大腿肌肉的横截面积和 IF。使用反复坐站、自主选择的步行速度和 6 分钟步行测试评估活动能力。
21 例 COPD 患者（年龄 71.3±8.1 岁，用力肺活量预计值的百分比为 47.2±12.9）和 21 名年龄、性别和体重匹配的健康受试者参加了研究。COPD 患者的平均膝关节伸肌力量（29%，P=.016）、大腿肌肉横截面积（17%，P=.007）和活动能力测量值（~23%，P≤.001）均降低。COPD 患者的膝关节伸肌和屈肌 IF 增加了 2 倍（P≤.005）。膝关节伸肌肌肉力量、质量和 IF 的测量值与活动能力测量值无关。
与健康对照组相比，中重度 COPD 患者的肌肉力量、质量、质量和活动能力均明显下降。需要更多的研究，包括更大的样本量，来阐明这些肌肉缺陷是否可以解释 COPD 患者的活动能力受损。
