Introduction to Accentuated Eccentric Training
Muscular hypertrophy can be induced by training through mechanical tension, muscle damage, and metabolic stress (4). The most effective method for inducing muscle hypertrophy is resistance training; it is theorized that eccentric actions have the greatest hypertrophic potential of all muscular contractions (3,4).
An eccentric contraction involves forcible elongation of the muscle; the highest level of force generation can be found during this portion of a movement (3). Furthermore, it has been observed that eccentric actions resulted in the greatest increases in anabolic signaling cascades and more rapid rises in muscle protein synthesis after a bout of resistance training using only eccentric actions when compared to concentric actions only (1, 2).
The observed hormonal responses, increased force production capability, and increased muscle damage from eccentric actions may provide in part, a basis for the theory that eccentric actions may be prioritized to maximize training induced hypertrophy.
The large strength capability of eccentric actions may be exploited through the use of accentuated eccentric training (AEL). AEL involves using eccentric loads greater than the prescribed concentric load for dynamic resistance exercises (5). This allows the larger force production capability of the eccentric portion of the movement to be capitalized upon while maintaining appropriate intensity for the concentric portion of the movement.
AEL is most commonly implemented in barbell training through the use of mechanical weight releasers which hang weight on each side of the barbell to overload the eccentric portion of the movement. These weight releasers will automatically release at or near the end of the eccentric movement, unloading the barbell for the subsequent concentric movement.
Overloading the eccentric portion of the movement may increase the hypertrophic potential from training due to the magnitude of loads which may be used and the resulting mechanical tension and muscle damage. Optimal loading prescriptions and practicality of application for hypertrophy-based training remains to determined.
References
1. Franchi, M.V., Atheron, P.J., Reeves, N.D., Fluck, M., Williams, J., Mitchell, W.K., Selby, A., Beltran Valls, R.M., & Narici, M.V. (2014). Architectural, Functional and Molecular Responses to Concentric and Eccentric Loading in Human Skeletal Muscle. Acta Physiologica, 210, 642-654.
2. Moore, D.R., Phillips, S.M., Babraj, J.A., Smith, K., & Rennie, M.J. (2005). Myofibrillar and Collagen Protein Synthesis in Human Skeletal Muscle in Young Men after Maximal Shortening and Lengthening Contractions. American Journal of Physiology, 288, 1153-1159.
3. Schoenfeld, B. J., & Grgic, J. (2018). Eccentric Overload Training: A Viable Strategy to Enhance Muscle Hypertrophy? Strength & Conditioning Journal (Lippincott Williams & Wilkins), 40(2), 78–81.
4. Schoenfeld, B. J. (2010). The Mechanisms of Muscle Hypertrophy and Their Application to Resistance Training. Journal of Strength and Conditioning Research, 24(10), 2857-2872.
5. Wagle, J.P., Taber, C.B., Carroll, K.M., Cunanan, A.J., Sams, M.L., Wetmore, A., Bingham, G.E., DeWeese, B.H., Sato, K., Stuart, C.A., & Stone, M.H. (2018). Repetition-to Repetition Differences Using Cluster and Accentuated Eccentric Loading in the Back Squat. Sports, 6(3), 59.