During locomotor training, reducing the amount of body weight support from 60% to 30% while maintaining treadmill speed would MOST likely result in which physiological change?

During locomotor training, reducing the amount of body weight support from 60% to 30% while maintaining treadmill speed would MOST likely result in which physiological change?

• A. Decreased lower extremity muscle activation
• B. Increased clonus in the lower extremities
• C. No measurable change in muscle activation
• D. Increased lower extremity muscle activation

Answer: (D)

Lower-extremity muscle activation increases as body-weight support decreases during treadmill locomotor training. When you drop from 60% to 30% support, the legs must bear more of the body’s weight and generate greater propulsive and stance-phase forces to maintain the same walking speed. This higher demand recruits more motor units and elevates neural drive to the leg muscles, so EMG activity rises. Keeping treadmill speed constant ensures the system must work harder to meet the same pace, further boosting activation. So the most likely change is increased activation of the muscles in the legs.

Lower-extremity muscle activation increases as body-weight support decreases during treadmill locomotor training. When you drop from 60% to 30% support, the legs must bear more of the body’s weight and generate greater propulsive and stance-phase forces to maintain the same walking speed. This higher demand recruits more motor units and elevates neural drive to the leg muscles, so EMG activity rises. Keeping treadmill speed constant ensures the system must work harder to meet the same pace, further boosting activation. So the most likely change is increased activation of the muscles in the legs.