Research Centre for Musculoskeletal Science and Sports Medicine, School of Healthcare Science, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK.
The Neuromuscular Centre, Winsford, UK.
J Cachexia Sarcopenia Muscle. 2018 Dec;9(6):1042-1052. doi: 10.1002/jcsm.12347. Epub 2018 Oct 19.
Muscular dystrophy (MD) is characterized by progressive muscle wasting and weakness, yet few comparisons to non-MD controls (CTRL) of muscle strength and size in this adult population exist. Physical activity (PA) is promoted to maintain health and muscle strength within MD; however, PA reporting in adults with MD is limited to recall data, and its impact on muscle strength is seldom explored.
This study included 76 participants: 16 non-MD (CTRL, mean age 35.4), 15 Duchenne MD (DMD, mean age 24.2), 18 Becker's MD (BMD, mean age 42.4), 13 limb-girdle MD (LGMD, mean age 43.1), and 14 facioscapulohumeral MD (mean age 47.7). Body fat (%) and lean body mass (LBM) were measured using bioelectrical-impedance. Gastrocnemius medialis (GM) anatomical cross-sectional area (ACSA) was determined using B-mode ultrasound. Isometric maximal voluntary contraction (MVC) was assessed during plantar flexion (PFMVC) and knee extension (KEMVC). PA was measured for seven continuous days using triaxial accelerometry and was expressed as daily average minutes being physically active (TPA ) or average daily percentage of waking hours being sedentary (sedentary behaviour). Additionally, 10 m walk time was assessed.
Muscular dystrophy groups had 34-46% higher body fat (%) than CTRL. DMD showed differences in LBM with 21-28% less LBM than all other groups. PFMVC and KEMVC were 36-75% and 24-92% lower, respectively, in MD groups than CTRL. GM ACSA was 47% and 39% larger in BMD and LGMD, respectively, compared with CTRL. PFMVC was associated with GM ACSA in DMD (P = 0.026, R = 0.429) and CTRL (P = 0.015, R = 0.553). MD groups were 14-38% more sedentary than CTRL groups, while DMD were more sedentary than BMD (14%), LGMD (8%), and facioscapulohumeral MD (14%). Sedentary behaviour was associated with LBM in DMD participants (P = 0.021, R = -0.446). TPA was associated with KEMVC (P = 0.020, R = 0.540) in BMD participants, while TPA was also the best predictor of 10 m walk time (P < 0.001, R = 0.540) in ambulant MD, revealed by multiple linear regression.
Quantified muscle weakness and impaired 10 m walking time is reported in adults with MD. Muscle weakness and 10 m walk time were associated with lower levels of TPA in adults with MD. Higher levels of sedentary behaviour were associated with reduced LBM in DMD. These findings suggest a need for investigations into patterns of PA behaviour, and relevant interventions to reduce sedentary behaviour and encourage PA in adults with MD regardless of impairment severity.
肌肉萎缩症（MD）的特征是进行性肌肉萎缩和无力，但在这个成年人群体中，与非 MD 对照组（CTRL）的肌肉力量和大小相比，很少有比较。提倡体育活动（PA）以保持 MD 患者的健康和肌肉力量；然而，MD 成年人的 PA 报告仅限于回忆数据，其对肌肉力量的影响很少被探索。
本研究纳入了 76 名参与者：16 名非肌肉萎缩症（CTRL，平均年龄 35.4 岁）、15 名杜氏肌肉萎缩症（DMD，平均年龄 24.2 岁）、18 名贝克氏肌肉萎缩症（BMD，平均年龄 42.4 岁）、13 名肢带型肌肉萎缩症（LGMD，平均年龄 43.1 岁）和 14 名面肩肱型肌肉萎缩症（平均年龄 47.7 岁）。使用生物电阻抗法测量体脂百分比（%）和瘦体重（LBM）。使用 B 型超声测量比目鱼肌内侧（GM）的解剖横截面积（ACSA）。通过足底屈肌（PFMVC）和膝关节伸肌（KEMVC）评估等长最大自主收缩（MVC）。使用三轴加速度计连续 7 天测量 PA，并表示为每天平均活跃分钟数（TPA）或平均每天清醒时间的久坐百分比（久坐行为）。此外，还评估了 10 米步行时间。
MD 组的体脂百分比（%）比 CTRL 组高 34-46%。DMD 组的 LBM 存在差异，与所有其他组相比，LBM 少 21-28%。与 CTRL 相比，MD 组的 PFMVC 和 KEMVC 分别低 36-75%和 24-92%。与 CTRL 相比，BMD 和 LGMD 组的 GM ACSA 分别大 47%和 39%。PFMVC 与 DMD（P=0.026，R=0.429）和 CTRL（P=0.015，R=0.553）中的 GM ACSA 相关。MD 组比 CTRL 组更久坐，而 DMD 比 BMD（14%）、LGMD（8%）和面肩肱型肌肉萎缩症（14%）更久坐。久坐行为与 DMD 参与者的 LBM 相关（P=0.021，R=-0.446）。TPA 与 BMD 参与者的 KEMVC 相关（P=0.020，R=0.540），而 TPA 也是运动型 MD 10 米步行时间的最佳预测因子（P<0.001，R=0.540），这是通过多元线性回归得出的。
报告了成年人 MD 中出现的量化肌肉无力和 10 米步行时间受损。肌肉无力和 10 米步行时间与 MD 成年人中较低水平的 TPA 相关。较高水平的久坐行为与 DMD 中的 LBM 减少相关。这些发现表明需要研究 PA 行为模式，并进行相关干预，以减少 MD 成年人的久坐行为并鼓励他们进行 PA，无论其残疾严重程度如何。
