Muscle force response characteristics of the slipping leg after an unexpected slip / 中国组织工程研究

ABSTRACT

BACKGROUND: Surface electromyogram signal is often used for qualitative analysis of muscles in the process of autonomic balance recovery after unexpected slips, but there is little research on the response characteristics of muscle force. OBJECTIVE: By the combination of gait analysis and simulation technology to study the muscle force response characteristics of the slipping leg when an unexpected slip of the heel occurs during walking straightly. METHODS: Five healthy subjects were recruited, wearing shoes uniformly, and asked to walk normally on two different straight footpaths (dry oil-free and oil-coated paths). The Vicon motion system and AMTI force measuring platform were used to collect the motion data. Based on the AnyBody Modeling System, a human musculoskeletal model matching with the subjects was established. The model was driven by the motion data, and the data of muscle force were collected and analyzed. RESULTS AND CONCLUSION: The recovery time after an unexpected slip was 15%-45% of a gait cycle and the single support phase was shortened. In the course of autonomic recovery, the muscle strength of the semitendinosus was increased by 25.6% (P < 0.05), and the muscle strength of the short head of biceps femoris increased by 14%. The maximum muscle strength of the medial gastrocnemius increased from 8.4 N/kg to 13.6 N/kg, and that of the lateral gastrocnemius increased by 17.4%. These findings indicate that in the process of recovering the balance after unexpected slips, the semitendinosus, biceps femoris, gastrocnemius and gastrocnemius produce great muscle force, and meanwhile, the time of single support phase is shortened, so as to quickly transfer the gravity of human body from the sliding leg to the dragging leg and keep the body balance. After the balance recovery from the slip, the human body will make a prediction in the later period of the swing phase to prevent the slip again.