In the ongoing pursuit of building quality muscle, improvements can move at a glacial pace. Our efforts to combat this harsh reality drives us to discover techniques that provide even the slightest opportunity to speed up our progress. One reoccurring theme? The potential for eccentric exercise to augment anabolic signaling, stimulating muscle protein synthesis and ostensibly resulting in improved muscle growth.
Eccentric – or “negative” – contractions have been found to generate stronger force production than their concentric – or “positive” – counterparts.
It’s important to understand the basics of assessing a training stimuli’s effect on skeletal muscle. In science, we have a variety of techniques to measure various indicators of muscle adaptation. For this article it’s important we know the basics. There are three primary directional indicators of muscle growth in corresponding order of significance.
A helpful analogy to understand their particular relevance, is to imagine building a brick wall, where the individual bricks are Amino Acids. Anabolic signaling would be similar to a Project Manager giving instruction to work on the site. This is instruction only, as many of you rebels know, direction does not automatically imply work is being done.
MPS on the other hand, is the workers responding to instruction and begin stacking bricks (amino acids). Now work is being performed, however several requirements are still needed to complete the wall – a steady supply of raw materials (amino acids), impetus of the workers to build, etc.
Finally, Hypertrophy is our proverbial brick wall. We’ve assembled the bricks (amino acids) in a collaborative network that is structurally sound and ready to serve its functional purpose. This final product is what we’re after – the other two measures are just directional proxies suggesting the potential that the wall is being built.
According to previous work1, the anabolic potential of maximal eccentric exercise demonstrates promise, at least in acute measures of signaling. Remember our example, this is merely your boss providing instruction. Our interest is in determining if these effects persist after prolonged high-volume training, specifically culminating in a meaningful adaptive response (hypertrophy).
Fortunately for us, this work has already been done. A well-run 20142 study leveraged several high-quality measures also comparing protein supplementation against carbohydrate controls.
The study found that although eccentric contraction caused a prolonged increase in acute anabolic signaling, no difference was seen when comparing contraction mode either in a single exercise bout or after 12 weeks of training in regards to muscle protein synthesis or hypertrophy. This inconsistency in acute vs. accumulated measures might be that at higher degrees of training volume, divergent effects of contraction mode “fade out” under a cascade of stress stimuli. Meaning that once you’ve reached a certain threshold of total work, the differences in response to contraction mode get diluted by the overriding stimulus of volume.
Alternatively, protein supplementation does appear to augment muscle hypertrophy over 12 weeks of training relative to an isocaloric carbohydrate (without protein) control.
Farup et el 2013.Indicating a statistically significant difference between supplementation (WHD & PLA (carbohydrate)), with no meaningful difference between contraction mode.
WHAT IT MEANS
Any training program should be supported by adequate protein supplementation (whole food and/or supplement) to drive optimal rates of MPS. Ultimately, the muscle’s adaptive response is not enhanced by prioritizing a contraction type, so long as volume and training intensity are sufficient.
It’s important to mention that this training protocol leveraged high volume, which may have attenuated any potential divergent response that might take place at lower training volumes. For those of you with an increasingly tight schedule, I’d suggest leveraging a variety of techniques for the central purpose of increasing intensity and overall volume (within the time you have).
Once again, ditch the gimmicks. The scientific consensus is that intense exercise is the closest thing we have to the fountain of youth; spanning mechanisms too complex for any one scientist to ever fully understand. Conveniently, your capacity to benefit from it’s implementation is completely independent of your propensity for understanding why. The polarizing effects that persist in it’s absence are equally deleterious and pervasive, exponentially heightened by the sedentary life of modern man/woman. Take a moment today to reflect and consider the implications of your own training intensity and persistence, for whatever reason: your kids, partner, personal health, improved aesthetic or simply expanding your experiential capacity for the world – anything that sufficiently drives consistency, identify it, leverage it and move vehemently towards an elevated self.
1. Eliasson J, Elfegoun T, Nilsson J, Kohnke R, Ekblom B, Blomstrand E (2006). Maximal lengthening contractions increase p70 S6 kinase phosphorylation in human skeletal muscle in the absence of nutritional supply. Am J Physiologyendocrinol Metab 291:E1197-1205
2. Rahbek S, Farup J, Moller A, Vendelbo M, Holm L, Jessen N, Vissing K (2014). Effects of divergent resistance exercise contraction mode and dietary supplementation type on anabolic signaling, muscle protein synthesis and muscle hypertrophy. Amino Acids. DOI 10.1007/s00726-014-1792-1
3. Farup J et al (2013) Whey protein hydrolysate augments tendon and muscle hypertrophy independent of resistance exercise contraction mode. Scadn J Med Sci Sports. doi: 10.1111/sms.12083;10