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Updated: May 30, 2026

In Vivo Measurement of Hindlimb Dorsiflexor Isometric Torque from Pig
Published on: September 3, 2021
Uninvolved versus target muscle contraction during contract: relax proprioceptive neuromuscular facilitation
Daniel Camara Azevedo1, Raphael Marques Melo, Ricardo Vidal Alves Corrêa
1Pontifícia Universidade Católica de Minas Gerais, Department of Physical Therapy, Belo Horizonte, MG, Brazil. danielazevedo@pucminas.br
Objective:
The purpose of this study was to compare the acute effect of the contract-relax (CR) stretching technique on knee active range of motion (ROM) using target muscle contraction or an uninvolved muscle contraction.
Design:
pre-test post-test control experimental design.
Setting:
Clinical research laboratory.
Participants:
Sixty healthy men were randomly assigned to one of three groups.
Interventions:
The Contract-Relax group (CR) performed a traditional hamstring CR stretch, the Modified Contract-Relax group (MCR) performed hamstring CR stretching using contraction of an uninvolved muscle distant from the target muscle, and the Control group (CG) did not stretch.
Main Outcome Measures:
Active knee extension test was performed before and after the stretching procedure.
Results:
Two-way between-within analysis of variance (ANOVA) results showed a significant interaction between group and pre-test to post-test (p < 0.001). Post-hoc examination of individual groups showed no significant change in ROM for the CG (0.8°, p = 0.084), and a significant moderate increase in ROM for both the CR (7.0°, p < 0.001) and MCR (7.0°, p < 0.001) groups.
Conclusions:
ROM gain following a CR PNF procedure is the same whether the target stretching muscle is contracted, or an uninvolved muscle is contracted.
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