Characterization of the Force Production Capabilities of Paralyzed Trunk Muscles Activated with Functional Neuromuscular Stimulation in Individuals with Spinal Cord Injury

This study explores how paralyzed trunk muscles respond to electrical stimulation. Researchers measured the force produced by these muscles when stimulated, assessing how strong they can become and in what directions they can exert force. This information is vital for designing systems that can help individuals with spinal cord injuries regain trunk stability and seated posture. The research also looked at whether combining the activation of multiple muscles results in a simple addition of their individual forces. This is important because it simplifies the design of control systems, as it allows engineers to predict the combined force without needing complex models. The study estimated the maximum resistance to external forces that each participant could achieve, which is essential for developing systems that can maintain seated balance against disturbances. The findings can help create more effective and personalized trunk control systems for individuals with spinal cord injuries.

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  Recruitment curves of most trunk and hip muscles fit sigmoid shaped curves with a regression coefficient above 0.75.
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  Co-activation of the muscles combined linearly across the hip and lumbar joint.
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  Subject specific perturbation plots showed one subject is capable of resisting up to a 300N perturbation anteriorly and 125N laterally; with some subjects falling considerably below these values.