ECCENTRIC OVER CONCENTRIC EXERCISES?

Since one of the first studies on eccentric exercises in 1938, there  has been discussion about the physiological difference in eccentric versus concentric exercises. A Concentric exercise is the shortening of a muscle as it contracts (ex: raising of a weight during a bicep curl). An Eccentric exercise is the contraction of a lengthening muscle (ex: lowering of a weight during a bicep curl). Eccentric exercises have been shown to be more beneficial in terms of muscle physiology efficiency. In addition, eccentric exercises have been advocated for management of tendinopathies, muscle strains and prevention of ACL injury. Is it true, should we focus on the eccentric phase of exercises for maximum benefits?

Here are a few central reasons why eccentric exercises give you more bang for your physiological buck!

  • During eccentric exercise oxygen consumption rarely rises to more than twice the resting value (1).
  • When a muscle is eccentrically lengthened the energy requiring drops significantly because ATP breakdown and heat production are slowed (1).
  • Bigland-Ritchie et al found the following: less muscle activity was required to maintain the same force during eccentric work than concentric work; fewer muscle fibers were required to exert a given force and there was a large reduction in oxygen uptake when muscles were eccentrically lengthened compared to concentric shortening (2).
  • Eccentric exercise has been shown to reduce hamstring injury rates by 60-70% in various sports (3).

Conclusion: Eccentric exercise results in lower oxygen consumption, more force production, less energy expenditure and has been shown to prevent injuries when compared to concentric exercise.

Try an eccentric exercise:

Nordic Hamstring Exercise: Kneel on the ground while a partner holds your ankles to the ground. Lean forward leading with hips and keeping your knee, hips, and shoulders in a straight line. Keep leaning as long as possible until you fall on the ground and stop yourself with your hands. Push yourself back up and repeat.

References:

1. Wilkie DR. Heat, work, and phosphorylcreatine break-down in muscle. Journal of Physiology 1968;195(1):57-183.

2. Bigland-Ritchie B, Woods JJ. Integrated electromyogram and oxygen uptake during positive and negative work. Journal of Physiology 1976;260(2):267-277.

3. Small K, et al. Effect of timing of eccentric hamstring strengthening exercises during soccer training: implications for muscle fatigability. J Strength Conditioning Research 2009;23(4):1077-1083.

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