Generalization of reflex gain scaling to coactivation conditions

Determine whether automatic gain-scaling of spinal short-latency and long-latency stretch reflexes observed under background load conditions generalizes to tasks involving muscle coactivation rather than reciprocal activation.

Background

Under background loads, increases in baseline muscle activity typically amplify short-latency stretch reflexes and, to a lesser extent, long-latency responses—a phenomenon termed automatic gain scaling.

The authors question whether these reflex gain-scaling findings, established under reciprocal activation paradigms with background loads, generalize to conditions involving muscle coactivation where both agonist and antagonist muscle groups are active.