Changes in corticospinal excitability during the preparation phase of ballistic and ramp contractions

Key points Changes in corticospinal excitability prior to a contraction may depend on its characteristics, including the rate of torque development. This study compared specific modulation cortical and spinal during preparation phase (last 500 ms before contraction) fast (ballistic) ramp contractions ankle dorsiflexors, using transcranial magnetic stimulation peripheral nerve stimulation. The results indicate earlier changes at than level both types. However, these adjustments are delayed ballistic relative contractions. suggests that time course change voluntary action is intended development upcoming contraction. Abstract present investigated (BAL) (RAMP) isometric To this end, young adults performed BAL RAMP (1500 rise time) contractions, reaching similar level, with dorsiflexor muscles. Transcranial motor cortex was randomly applied record evoked potentials (MEP) tibialis anterior last preceding ( n = 16). Short‐interval intracortical inhibition (SICI; 10) neurone (F‐wave occurrence; 8) were also assessed period. Data averaged over 100 windows beginning onset An increase MEP amplitude decrease SICI observed from 200–100 300–200 P < 0.05), respectively, greater within window 0.05). F‐wave occurrence, used assess excitability, increased (200–100 ms, 0.05) but not obtained few participants confirmed steeper These