INTRODUCTION: In this study we compared passive mechanical properties of gastrocnemius muscle-tendon units, muscle fascicles, and tendons in control subjects and people with ankle contractures after spinal cord injury. METHODS: Passive gastrocnemius length-tension curves were derived from passive ankle torque-angle data obtained from 20 spinal cord injured subjects with ankle contractures and 30 control subjects. Ultrasound images of muscle fascicles were used to partition length-tension curves into fascicular and tendinous components. RESULTS: Spinal cord injured subjects had stiffer gastrocnemius muscle-tendon units (stiffness index: 74.8 +/- 27.0 m(-1) ) than control subjects (54.4 +/- 17.7 m(-1) ) (P = 0.004). Muscle-tendon slack lengths, as well as slack lengths and changes in length of fascicles and tendons, were similar in the two groups. CONCLUSIONS: People with ankle contractures after spinal cord injury have stiff gastrocnemius muscle-tendon units. It is not clear whether this reflects changes in properties of muscle fascicles or tendons. Muscle Nerve 46: 237-245, 2012.
AD - The George Institute for Global Health, Sydney, New South Wales, Australia. AN - 22806373 BT - Muscle and Nerve DP - NLM ET - 2012/07/19 LA - eng M1 - 2 N1 - Diong, Joanna H LHerbert, Robert DHarvey, Lisa AKwah, Li KhimClarke, Jillian LHoang, Phu DMartin, Joshua HClarke, Elizabeth CBilston, Lynne EGandevia, Simon CUnited StatesMuscle Nerve. 2012 Aug;46(2):237-45. doi: 10.1002/mus.23356. N2 -INTRODUCTION: In this study we compared passive mechanical properties of gastrocnemius muscle-tendon units, muscle fascicles, and tendons in control subjects and people with ankle contractures after spinal cord injury. METHODS: Passive gastrocnemius length-tension curves were derived from passive ankle torque-angle data obtained from 20 spinal cord injured subjects with ankle contractures and 30 control subjects. Ultrasound images of muscle fascicles were used to partition length-tension curves into fascicular and tendinous components. RESULTS: Spinal cord injured subjects had stiffer gastrocnemius muscle-tendon units (stiffness index: 74.8 +/- 27.0 m(-1) ) than control subjects (54.4 +/- 17.7 m(-1) ) (P = 0.004). Muscle-tendon slack lengths, as well as slack lengths and changes in length of fascicles and tendons, were similar in the two groups. CONCLUSIONS: People with ankle contractures after spinal cord injury have stiff gastrocnemius muscle-tendon units. It is not clear whether this reflects changes in properties of muscle fascicles or tendons. Muscle Nerve 46: 237-245, 2012.
PY - 2012 SN - 1097-4598 (Electronic)0148-639X (Linking) SP - 237 EP - 45 T2 - Muscle and Nerve TI - Passive mechanical properties of the gastrocnemius after spinal cord injury VL - 46 ER -