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Updated: Jul 11, 2026

Direct Linear Transformation for the Measurement of In-Situ Peripheral Nerve Strain During Stretching
Published on: January 12, 2024
Acute stretch perception alteration contributes to the success of the PNF "contract-relax" stretch
Ulrike H Mitchell1, J William Myrer, J Ty Hopkins
1Department of Exercise Sciences, Brigham Young University, Provo, UT, USA.
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.
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