Format

Send to

Choose Destination
Front Physiol. 2017 Jul 4;8:447. doi: 10.3389/fphys.2017.00447. eCollection 2017.

Skeletal Muscle Remodeling in Response to Eccentric vs. Concentric Loading: Morphological, Molecular, and Metabolic Adaptations.

Author information

1
MRC-ARUK Centre for Musculoskeletal Ageing Research, School of Medicine, University of NottinghamDerby, United Kingdom.
2
Laboratory for Muscle Plasticity, Department of Orthopaedics, Balgrist University Hospital, University of ZurichZürich, Switzerland.
3
Faculty of Science and Engineering, School of Healthcare Science, Manchester Metropolitan UniversityManchester, United Kingdom.

Abstract

Skeletal muscle contracts either by shortening or lengthening (concentrically or eccentrically, respectively); however, the two contractions substantially differ from one another in terms of mechanisms of force generation, maximum force production and energy cost. It is generally known that eccentric actions generate greater force than isometric and concentric contractions and at a lower metabolic cost. Hence, by virtue of the greater mechanical loading involved in active lengthening, eccentric resistance training (ECC RT) is assumed to produce greater hypertrophy than concentric resistance training (CON RT). Nonetheless, prevalence of either ECC RT or CON RT in inducing gains in muscle mass is still an open issue, with some studies reporting greater hypertrophy with eccentric, some with concentric and some with similar hypertrophy within both training modes. Recent observations suggest that such hypertrophic responses to lengthening vs. shortening contractions are achieved by different adaptations in muscle architecture. Whilst the changes in muscle protein synthesis in response to acute and chronic concentric and eccentric exercise bouts seem very similar, the molecular mechanisms regulating the myogenic adaptations to the two distinct loading stimuli are still incompletely understood. Thus, the present review aims to, (a) critically discuss the literature on the contribution of eccentric vs. concentric loading to muscular hypertrophy and structural remodeling, and, (b) clarify the molecular mechanisms that may regulate such adaptations. We conclude that, when matched for either maximum load or work, similar increase in muscle size is found between ECC and CON RT. However, such hypertrophic changes appear to be achieved through distinct structural adaptations, which may be regulated by different myogenic and molecular responses observed between lengthening and shortening contractions.

KEYWORDS:

concentric exercise; eccentric contraction; eccentric exercise; mechanotransduction; muscle architecture; muscle hypertrophy; muscle remodeling; muscle signaling

Supplemental Content

Full text links

Icon for Frontiers Media SA Icon for PubMed Central
Loading ...
Support Center