ABSTRACT
PURPOSE: Neural and peripheral effects of induced muscle pain on explosive force production were investigated. METHODS: Nine participants performed two maximal, six explosive, and six electrical stimulations induced (twitches and octets) isometric knee extensions before and after (15 min of rest) receiving an intramuscular injection of hypertonic saline (pain inducer) or isotonic (placebo) infusions in two laboratory visits separated by 7 days. RESULTS: It was observed a reduction of peak torque production in maximal voluntary contraction in both conditions (9.3 and 3.3% for pain and placebo, respectively) and in the rate of torque development in placebo (7%). There was an increase in the rate of torque development for twitch and octets (10.5 and 15.8%, respectively) in the pain condition and peak torque for twitch (12%) in both conditions (as did the total rate of torque development for octets). CONCLUSION: Force production decreases and increases during voluntary and involuntary contractions, respectively, suggesting that acute pain impairs force production via central mechanisms.
