Vikne H, Refsnes PE, Ekmark M, Medbø JI, Gundersen V, Gundersen K. Muscular performance after concentric and eccentric exercise in trained men. Med Sci Sports Exerc. 2006 Oct;38(10):1770-81.
This study are about previously resistance-trained men (age 26.9 +/- 3.4 yr). The effects of concentric and eccentric training is compared on performance and structural muscle measures.
The concentric training group (8 people) and the eccentric training group (9 people) performed during 12 week elbow flexors workouts. Measurement criteria were the angular velocity at standard loads and maximum concentric and eccentric strength. Additionally hypertrophy (muscle growth) were measured on muscle cross-sectional areas and single cell cross-sectional areas.
The results for the strength results show that concentric strength increased by +18% for the concentric group and +14% for the eccentric group. Eccentric strength increased by +9% for the concentric group and +26% for the eccentric group. Maximum angular velocity increased similar in both groups.
The results for the muscle mass growth results show that the cross-sectional area of both the elbow flexors did not increase at the concentric group but did increase with +11% on the eccentric group, which is impressive. Additionally the type I and type IIA fibers did not increase in the concentric group but increased in the eccentric group. In addition, the type II fibers of the relative cross-sectional area increase from 64% to 73% in the eccentric training group.
In conclusion, the muscle strength results were in small favor for eccentric training and the muscle mass growth results were in big favor for the eccentric training compared to traditional weight-based concentric training.