The Effect of Remote Voluntary Contractions on Knee Extensor Torque

• Published in: Medicine and science in sports and exercise 2008-10, Vol.40 (10), p.1805-1809
• Main Authors: EBBEN, William P, LEIGH, David H, GEISER, Christopher F
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Humans; Isometric Contraction; Knee - physiology; Male; Space life sciences; Torque; Valsalva Maneuver; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 0195-9131; 1530-0315
• DOI: 10.1249/mss.0b013e31817dc4ad

Concurrent activation potentiation (CAP) is purported to enhance the force capabilities of muscles via the contraction of muscles remote to the prime mover. This phenomenon has been described as remote voluntary contractions (RVC). The objective of this study was to assess a variety of RVC and their effect on isometric knee extensor torque to evaluate the existence of CAP. Twelve males who regularly participated in lower body resistance training served as subjects. Subjects performed maximum voluntary isometric contractions (MVIC) of the knee extensors without RVC, as well as in a variety of conditions that included RVC, in a randomized order. The RVC conditions included jaw clenching, bilateral gripping, jaw clenching combined with contralateral gripping and the Valsalva maneuver, and the combination of jaw clenching, bilateral gripping, and the Valsalva maneuver. A repeated-measures ANOVA revealed significant main effects (P = 0.001) for RVC condition. Bonferroni-adjusted post hoc analysis identified several differences in RVC compared with the NO-RVC condition (P < 0.05). The RVC condition including jaw clenching, bilateral gripping, and the Valsalva maneuver resulted in approximately 14.6% and 14.8% greater average and peak torque, respectively, compared with the NO-RVC condition. These findings indicate that RVC augment torque, which may be useful during the performance of resistance training as well as athletic tasks that require acute maximal strength. These findings support the existence of the CAP phenomenon.