Comparison Between Contract-Relax Stretching and Antagonist Contract-Relax Stretching on Gastrocnemius Medialis Passive Properties.

Taizan Fukaya,Andreas Konrad,Remi Onuma,Riku Yoshida,Masatoshi Nakamura,Ryosuke Kiyono,Kaoru Yahata,Shigeru Sato,Koki Yasaka

doi:10.3389/fphys.2021.764792

Abstract

Antagonist contract-relax stretching and contract-relax stretching is commonly used in sports practice and rehabilitation settings. To date, no study has compared these modalities regarding muscle stiffness and stretch tolerance. This study aimed to investigate the effects of contract-relax and antagonist contract-relax stretching on dorsiflexion range of motion (ROM), stretch tolerance, and shear elastic modulus. Forty healthy participants (24 men and 16 women) took part in the study. Participants were randomly assigned to perform either contract-relax stretching or antagonist contract-relax stretching for 2 min. Outcomes were assessed on ROM, stretch tolerance, and shear elastic modulus before and after stretching. The ROM and stretch tolerance significantly increased after both contract-relax stretching (+ 5.4 ± 5.8°, p < 0.05; + 3.5 ± 8.0 Nm, p < 0.05) and antagonist contract-relax stretching (+ 6.1 ± 4.9°, p < 0.05; + 4.2 ± 6.4 Nm, p < 0.05); however, no significant difference was found between the two groups. Alternatively, the shear elastic modulus significantly decreased after both contract-relax (–31.1 ± 22.6 kPa, p < 0.05) and antagonist contract-relax stretching (–11.1 ± 22.3 kPa, p < 0.05); however, contract-relax stretching (–41.9 ± 19.6%) was more effective than antagonist contract-relax stretching (–12.5 ± 61.6%). The results of this study suggest that contract-relax stretching instead of antagonist contract-relax stretching should be conducted to decrease muscle stiffness. However, either contract-relax or antagonist contract-relax stretching can increase ROM.

Highlights

Range of motion (ROM), which is the ability to move a joint and ease muscle stiffness, is essential in sports performance and activities of daily living (Mulholland and Wyss, 2001; Hemmerich et al, 2006), and it might influence the risk of muscle strain injury (Witvrouw et al, 2003)
No significant difference was found between CR and antagonist CR (ACR) stretching for DF ROM at PRE stretching (p = 0.52)
No significant difference was noted between CR and ACR stretching for the passive torque at DF ROM at PRE stretching (p = 0.51)

Summary

Introduction

Range of motion (ROM), which is the ability to move a joint and ease muscle stiffness, is essential in sports performance and activities of daily living (Mulholland and Wyss, 2001; Hemmerich et al, 2006), and it might influence the risk of muscle strain injury (Witvrouw et al, 2003). In sports and clinical settings, static stretching (SS) is a common and easy technique to increase ROM, which is involved in changing the viscoelastic properties of the muscle-tendon unit (i.e., decreasing muscle stiffness) (Morse et al, 2008) and increasing an individual’s capacity to tolerate loading before stretch termination (i.e., increased stretch tolerance) (Magnusson et al, 1996). Kay et al (2015) reported that CR stretching was more effective in increasing ROM and decreasing passive muscle-tendon stiffness than SS. Ferber et al (2002) reported that antagonist CR (ACR) stretching, which is a combination of SS and voluntary contraction of the antagonist muscle group in a stretched position, that is, “active stretching,” was more effective in changing ROM than CR stretching for older participants. No study has compared ACR stretching with CR stretching regarding these outcomes

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