Eccentric exercise – slower might not be more productive


Eccentric exercise – slower might not be more productive
by Anthony Roberts

If I were to grab a bunch of bodybuilding magazines off the shelf this month, no doubt I’d see countless articles that talk about the importance of the eccentric (lowering) portion of various exercises. “Slowly lower the weight” has been part of bodybuilding dogma for decades, with recommendations ranging from a 4 second lowering phase and upwards. This, they tell us, is where muscle is built – the Holy Grail of hypertrophy. Some bodybuilders even take it to the next level by doing “negative reps” at the end of their sets, where they slowly -agonizingly slowly – lower the weight while a spotter helps them lift it. However, although lowering a weight doesn’t make you much stronger, it does happen to cause more damage to your muscle than actually lifting the weight. Because of this increased damage it is thought that prolonging the eccentric portion of the lift will result in substantially more hypertrophy.

But a strange thing happens when we look at Olympic Weightlifters, who typically don’t do much eccentric training at all (*they drop the bar to the floor at the top of a max lift): we see a reasonable amount of hypertrophy, albeit without the same level of conditioning we see with bodybuilders. And of course powerlifters often display an extreme level of hypertrophy despite little to no emphasis, other than what’s required in competition, for the eccentric range.

And, bodybuilding being what it is, if lowering the weight for 3 seconds causes increased muscle growth, then lowering it for six seconds must cause even more growth, right? Eventually we even saw “super slow” protocols that advocated 30-60 second eccentric training. And, in contrast to the extreme emphasis on the eccentric portion of the rep, we now have a study that shows the hypertrophic pathways appear to be similarly stimulated with both slow and quick eccentric contractions. Lowering the weight under control, and avoiding injury is a good thing, but perhaps lowering it to an exaggerated tempo may not produce additional results:

Applied Physiology, Nutrition, and Metabolism, 2011, 36:283-290, 10.1139/h10-111

Abstract

The solid bars represent quick lowering of the weight, the empty bars represent slow lowering.

It has been suggested that muscle tension plays a major role in the activation of intracellular pathways for skeletal muscle hypertrophy via an increase in mechano growth factor (MGF) and other downstream targets. Eccentric exercise (EE) imposes a greater amount of tension on the active muscle. In particular, high-speed EE seems to exert an additional effect on muscle tension and, thus, on muscle hypertrophy. However, little is known about the effect of EE velocity on hypertrophy signaling. This study investigated the effect of acute EE-velocity manipulation on the Akt/mTORCI/p70S6K hypertrophy pathway. Twenty subjects were assigned to either a slow (20°·s–1; ES) or fast EE (210°·s–1; EF) group. Biopsies were taken from vastus lateralis at baseline (B), immediately after (T1), and 2 h after (T2) the completion of 5 sets of 8 repetitions of eccentric knee extensions. Akt, mTOR, and p70S6K total protein were similar between groups, and did not change postintervention. Further, Akt and p70S6K protein phosphorylation were higher at T2 than at B for ES and EF. MGF messenger RNA was similar between groups, and only significantly higher at T2 than at B in ES. The acute manipulation of EE velocity does not seem to differently influence intracellular hypertrophy signaling through the Akt/mTORCI/p70S6K pathway.

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