Time but not force is transferred between ipsilateral upper and lower limbs.

Area of Science:

• Motor control
• Neuroscience
• Biomechanics

Background:

• Understanding motor control and interlimb transfer is crucial for rehabilitation and skill acquisition.
• Isometric contractions are fundamental movements studied to reveal underlying neural mechanisms.
• Previous research has explored motor learning but less on specific force and timing accuracy transfer between limbs.

Purpose of the Study:

• To compare force and time accuracy in goal-directed upper and lower limb isometric contractions.
• To identify transferable components of motor performance between limbs following practice.
• To investigate the neural basis of motor control for isometric contractions.

Main Methods:

• Ten healthy adults performed 100 trials of isometric contractions using ankle dorsiflexor and elbow flexor muscles.
• Participants matched peak force to a force-time target, with accuracy measured by force and timing errors.
• Interlimb transfer was assessed by comparing performance before and after practice with the contralateral limb.

Main Results:

• Ankle dorsiflexor contractions showed greater peak force error and variability than elbow flexor contractions.
• Timing error and variability were similar between upper and lower limb contractions.
• Significant transfer of timing accuracy, but not force accuracy, was observed between limbs.

Conclusions:

• Motor performance timing, unlike force production, can be transferred between upper and lower limbs.
• Practice with one limb improves the timing accuracy of contractions in the other limb.
• Findings suggest a common neural pathway or control mechanism for the timing of isometric aiming contractions across different limbs.