Hybrid stimulation enhances torque as a function of muscle fusion in human paralyzed and non-paralyzed skeletal muscle

This study investigates how different patterns of electrical stimulation affect muscle strength (torque) in people with and without spinal cord injuries. The researchers used a combination of regular stimulation and paired pulses (doublets) to see how they could maximize muscle work. The study found that using doublets at both the beginning and middle of the stimulation pattern was most effective at increasing torque. Also, the doublets worked best when the background stimulation frequency was low. Even when the muscles were fatigued, the hybrid stimulation method continued to be effective in paralyzed muscles, likely because these muscles don't fuse as much between pulses compared to healthy muscles.

• 1
  Stimulation trains with doublets at both the start and middle yielded the most consistent enhancement of torque.
• 2
  The torque contribution of the doublet was greatest at low stimulus frequencies.
• 3
  The low relative fusion of untrained paralyzed muscle preserved the efficacy of the doublet even during fatigue.