Effect of time of concentric muscle actions on strength, hypertrophy, and specific tension in resistance-trained women
Date
1997
Authors
Gillies, Ellen Maureen
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Abstract
The study investigated the effects of different concentric muscle action times during resistance training on neuromuscular changes. Eccentric muscle action time was 2 s for both groups while the concentric phases were 8 s for the Super Slow (SS) group and 2 s for the Controlled Tempo (CT) group. 21 resistance-trained women volunteered to participate and were randomly assigned to either the SS group (n = 13, age 28.6 +/- 5.5 [SD]) or the CT group (n = 8, age 26.3 +/- 9.3). Training was conducted 3 times per week for 8 weeks with 2 sets (SS) or 4 sets (CT) of 8-10 RM using free weights to exercise the elbow flexors and extensors. 1 RM strength, 8 RM strength, relaxed and flexed arm girths, and skinfolds were measured at 0, 4, and 8 weeks. Muscle cross-sectional area (CSA), evaluated using magnetic resonance imagery, and specific tension (kg/cm2), were measured at 0 and 8 weeks. The SS and CT training protocols elicited significant and similar increases in flexor and extensor 1 RM strength at Weeks 4 and 8 (p < .01). Both groups had significant increases in 8 RM flexor and extensor strength at Week 4 (p < .01), while only the SS group had significant increases at Week 8 (p < .01). Arm girths increased significantly (p < .01) in both groups at Week 4, while only the SS group had significant (p < .05) increases at Week 8. Extensor CSA increased significantly (p < .05) in both groups, while only the SS group had significant (p < .01 ) increases in flexor CSA. The groups had significant increases in specific tension of both muscle groups at Week 8 (p < .05). In conclusion, two sets of resistance training exercises performed with a slow concentric phase were as effective as 4 sets performed more quickly, in producing increases in strength, muscle cross-sectional area, and specific tension in resistance-trained women.