Acute stretch perception alteration contributes to the success of the PNF "contract-relax" stretch.

CONTEXT Some researchers have suggested that an alteration of stretch perception could be responsible for the success of the contract-relax (CR) stretch, a stretch technique derived from proprioceptive neuromuscular facilitation (PNF). OBJECTIVE This study was conducted to determine if the alteration of the stretch perception is a possible explanation for the range of motion (ROM) gains of the CR stretch. PARTICIPANTS Eighteen subjects performed two stretches in randomized order: the slow stretch and the CR stretch. MAIN OUTCOME MEASURE The stretch intensity was controlled. The stretch force was measured and compared between the slow stretch and CR stretch. RESULTS There was a significant difference between the stretch force that could be applied in the PNF stretch (126.0 N) and the slow stretch (108.4 N); P = 0.00086. The average stretch tolerance progressively increased with successive trials from 120.6 N in the first trial to 132.4 N in the fourth trial. CONCLUSION The alteration of stretch perception plays a role in the success of the CR form of PNF stretching. At least four repetitions of the CR stretch are recommended to get the greatest ROM gain.