T Nation

Reply: Doug's tempo article

Hey t-brothers, if you haven’t noticed yet, there’s a glitch on this forum, which makes some posts “inactive.” The web gurus are working on it now.

There was a question earlier about my article on tempo which I tried to respond to a few times, but nothing got through. The question referred to a feedback letter by Professor McBride of the University of Newcastle, Australia, that criticized the tempo article. Just so you didn’t think I was avoiding the question, I’ll answer here:


As I saw it, Professor McBride had two problems with the article. He proposed that…


1)The numbers used in the examples were not accurate, and


2)Slowing down the eccentric makes the exercise “harder” not because of increased force production, but rather due to increased Time Under Tension.


I’ll address each of these issues independently:

1)accuracy: Professor, you are 100% right. I did not measure the force produced by a trainee in any way, shape, or form. The numbers I used were complete estimates on my part, and were not intended to be precise. However, it has absolutely zero impact on the point of the article. I felt the numbers made the concept more straight-forward and easy to understand, so I included them.

2)force: Sorry, but you're dead wrong, Professor. Force production does in fact increase with slower eccentrics. I'm not going to get too deep into force production curves, but as is widely recognized, elastic energy contributes a higher percentage of work given faster eccentrics. So, while force greater than the weight of the bar is required during the transitional phase of a bench press if the trainee does not bounce the weight off his/her chest, with a fast eccentric, much of this added force is accounted for via elastic energy, or the effects of the stretch shortening cycle. That means that when slower eccentrics are used, you guessed it, the trainee must apply higher levels of force to slow the weight down and make the transition into the concentric. Not only that, but less force is also applied in the top portion of an eccentric with a fast tempo. To get the bar moving fast, the difference between the upward vertical force and the downward vertical force must be substantial. Of course, once the bar reaches its required speed, you must equal the weight of the bar in order to keep the bar from accelerating. However, I would argue that with a fast enough eccentric, the bar never actually travels at a constant speed, but rather goes from accelerating (where you apply very little force), to decelerating (where elastic energy provides a great deal of help). With a slow eccentric tempo, the difference between upward and downwards force doesn't have to be as significant.

The bottom line: Slower eccentrics yield higher force production.