In Part 1 of this series I took a very long look at eccentric contractions and their role in stimulating muscle growth. I also looked at some of the other possible factors that may signal muscle hypertrophy to take place including adenosine tri phosphate depletion, creatine phosphate depletion, increased blood flow, restricted blood flow, oxygen deprivation and time under tension. Today I’m going to continue talking about time under tension and move on to some other possible reasons as to why training to failure may not be necessary in order to build new muscle tissue.
It has been theorized and studied extensively by Goldspink et al (1), and everyone seems to agree that the most critical component of muscle growth is time under tension. Remember that 8 reps at 80 to 85 percent of our one rep max that recruits 100 percent of our muscle fibers from the first rep? What if we lifted those reps as fast as we could and reached failure on the 8th rep but in less than 10 seconds? Would that be as beneficial to muscle growth as lifting that same weight, at a much slower pace so the set took 60 seconds? The above listed possible reasons for stimulating new mass such as ATP depletion, CP depletion, restricted and increased blood flow and oxygen deprivation will certainly have taken place much more extensively due to the longer time under tension, so with this information, is the final rep what is necessary to cause muscle growth, or is it the amount of time under tension?
I realize I just asked a lot of questions and didn’t answer any, although I’m hoping that you are coming to some conclusions on your own. This brings me to another question: is there any proof whatsoever that training to failure indeed does stimulate muscle hypertrophy? I’m glad I asked. Although not exactly an airtight scientific study, there are those Olympic lifters to look to as an example yet again. Yes a large degree of their development may in fact be genetic but there is no question that many of these lifters exemplify very muscular physiques. This brings some of our above-mentioned conclusions into question. Olympic lifters NEVER train to failure and secondly, the Olympic lifts contain no eccentric lifting whatsoever. Olympic lifters perform their lifts extremely quickly, so does this mean that slow and controlled lifts with a focus on the negative are the way to go? Not if Olympic lifting is used as proof to the contrary. The rep speed of an Olympic lift is as fast as humanly possible and when the lift is completed the weight is dropped, removing entirely the negative portion of the lift.
Another example is that of laborers and tradesmen. Ever noticed the size of the forearms on a carpenter or framer before? This hypertrophy has taken place under very light workloads, although very repetitive movements. This brings time under tension back into the conversation. Yes, it is true that Olympic lifters lift extremely quickly, but they also train very often. Often times performing the same lifts multiple times per day, every day. This volume approach to training these quick lifts results in a cumulative form of time under tension. The individual reps may be as short as a second, but when added up over the course of the day, the muscles of these lifters have indeed been placed under tension for a considerable time.
I’m going to bring another consideration to this conversation that has yet to be said and that is the issue of safety. I don’t know about you, but I never go to legitimate failure on lifts such as squats or deadlifts. Even heavy leg presses I tend to stop a rep or two shy of what I would be capable of doing. As much as training like a hardcore psycho is cool to say on twitter (there are a whole lot of pretend hardcore trainees on that social media and every social media platform, but I’m not getting into that here), being crippled as the result of going until full muscular lockup with a loaded bar on your back being supported by your spine is not. Having said that, I can honestly say that I’ve never trained my lower body in the big lifts to failure and my lower body does not lag behind my upper body at all. I’ve always made it a point to train my lower body harder than my upper as more than half of our muscle mass is located there. By harder in this case I mean more volume. More volume once again means more cumulative time under tension. I think we are beginning to come to a definitive conclusion here, whether it is from scientific or my own anecdotal evidence being put forth.
When we get together next I’d like to take one last look at this whole training to failure thing. If anything I’m going to take an entirely different look at the question with different information to see what conclusions we can come to apart from the somewhat obvious necessity of time under tension in order to induce hypertrophy. Until then my friends,
1. Seminal Review Article by Goldspink et. al.
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