| Purpose. The purpose of the study was to examine segmental reflex organization in untrained subjects and endurance-trained athletes using a conditioned reflex paradigm. The study also examined the role of cutaneous receptors on conditioned reflex function. The patellar tendon reflex, the Achilles tendon reflex and the tibial nerve Hoffmann reflex were examined.;Methodology. Twenty-four college-age subjects (12 subjects/group) were tested. Nine experimental treatments were randomly assigned: (1) patellar tendon reflex conditioned by a tap to the contralateral patellar tendon, (2) Achilles tendon reflex conditioned by a tap to the contralateral Achilles tendon, (3) Achilles tendon reflex conditioned by a tap to the contralateral patellar tendon, (4) Achilles tendon reflex conditioned by a tap to the ipsilateral patellar tendon, (5) patellar tendon reflex conditioned by a tap to the contralateral patellar tendon, with five percent lidocaine applied to the conditioning leg, (6) Achilles tendon reflex conditioned by a tap to the contralateral Achilles tendon with five percent lidocaine applied to the conditioning leg, (7) tibial nerve Hoffmann reflex conditioned by a contralateral tibial nerve Hoffmann reflex, (8) tibial nerve Hoffmann reflex conditioned by a tap to the contralateral Achilles tendon, and (9) tibial nerve Hoffmann reflex conditioned by an ipsilateral tibial nerve Hoffmann reflex. For each of the treatments, the conditioning stimulus preceded the test reflex by 10, 25, 40, 55, 70, 85, 100, 115, 130 or 145 milliseconds. Dependent measures included: peak isometric force, isometric impulse, contraction time, force latency, EMG latency, electromechanical delay, peak to peak EMG activity, integrated EMG and half-relaxation time.;Conclusions. The patellar tendon reflex was facilitated by a conditioning stimulus, while the Achilles tendon reflex was inhibited by a conditioning stimulus.;Endurance-trained athletes exhibited diminished unilateral patellar tendon reflexes, but not Achilles tendon reflexes nor tibial nerve Hoffmann reflexes.;Endurance-trained athletes exhibited a greater facilitation to the patellar tendon reflex caused by a conditioning stimulus, and a greater inhibition to the Achilles tendon reflex caused by a conditioning stimulus.;Lidocaine application attenuated both the facilatory effect found for the conditioned patellar tendon reflex and the inhibitory effect found for the conditioned Achilles tendon reflex. |
