Baker Conditioning

Eccentric Training for Maximum Strength Gains!

By: Justin Baker CSCS, BSc. Kin

If you have ever spent some time in a gym, you probably learned fairly quickly that it is crucial to lower your weights under control.  The most obvious reason we control our weights is for safety.  However, what is less commonly known is that the return or secondary phase of any resistance training movement is extremely important for developing muscular strength and consequentially, hypertrophy (muscle growth).

The return phase of a repetition is known as the eccentric contraction.  In an eccentric contraction, the muscle produces force but not enough to overcome the resistance.   Essentially, the muscle produces force while it lengthens back to the resting position.  Conversely, a concentric contraction is the shortening contraction, or movement away from resting length.  In a biceps curl, the concentric portion is performed while curling the dumbbell up and the eccentric while lowering the dumbbell back down to the side.

The reason why eccentric contractions are so effective at improving strength is related to how much muscle is required to produce a given amount of force.  When performing a repetition of any exercise, one thing you will always notice is that the movement is easier eccentrically than concentrically.  To use the biceps curl as an example once more, it is much easier to lower the dumbbell back down to the side than to curl it up to the shoulder.  The reason for the ease of an eccentric contraction is directly related to mechanisms within the muscle at the cellular level. To keep things simple, each individual muscle cell, or fiber, is stronger eccentrically than concentrically. Thus, for a given amount of force production, a fewer number of fibers are recruited in an eccentric contraction compared to a concentric one. Despite the fact that individual muscle fibers are stronger eccentrically, the demand placed on the fibers in this type of contraction is greater. This greater demand leads to a restructuring of the proteins that make up the fiber such to a greater extent than the restructuring stimulated by concentric contractions.

In addition to the hypertrophy of contractile muscle fibers, structural proteins that make up the muscle’s framework, or cytoskeleton, have also been shown to react favorably to eccentric contractions. In a study that compared the effect of endurance cycling to resistance training on protein alterations, Parcell et al. demonstrated that progressive eccentric overload training stimulated a greater restructuring of the desmin structural protein than traditional concentrically dominant training techniques (2009).

In closing, it is the adaptations in both contractile and structural proteins that contribute to improvements in both strength and muscular hypertrophy. So next time you are lifting, make sure you lower the weight under control! A great tempo to use when training for hypertrophy is 1 second for the concentric phase and 2 seconds for the eccentric phase. If you’re advanced in your training, you can try eccentric overload training. This technique employes greater than maximum concentric loads to perform near maximal eccentric contractions. Eccentric overload training is very demanding on the body and should not be used regularly for an extended duration. If you want to give eccentric overload training a try, make sure you have 1 to 2 spotters available depending on the exercise. The spotters are responsible for providing assistance or “taking” the concentric portion of the repetition and the exerciser attempts to perform the eccentric portion on his or her own.

July 28th 2008.

References:

(1) Parcell, C.A. Woolstenhulme, MT, Sawyer, RD. Structural protein alterations to resistance and endurance cycling exercise training. The Journal of Strength and Conditioning Research. 23(2). 2009.