Response to Questions About Mechanical Work and Repetition Speed

I received several e-mails with questions about and requests to repost the following response I wrote to a question in the comments on My Philosophy of Exercise.  If you find anything I write on this web site helpful I encourage you to share it and appreciate you doing so, but please link back to the original, and limit copying and pasting to brief quotes. By having people read and comment on things I write here at Drew Baye’s High Intensity Training rather than on other sites or forums I am able to respond to everything in one place for the benefit of my other readers, and provide additional information or thoughts on the original post or comments.

My response, to a question about mechanical work and repetition speed:

“The most important thing to keep in mind is the key appears to be relative effort, and not load. A wide range of loads and repetition ranges have been shown to be equally effective for strength and size increases in the long run, provided they are used with a high level of effort. With this in mind, the ideal approach would be to use the lowest load required to get the job done. Rather than focus on how much weight you can lift, you should focus on how intensely you are able to get your muscles to contract with a given weight, how efficiently you can use that weight to fatigue the muscles, and only increase it when you are unable to achieve failure within a reasonable time frame.

Rather than trying to lift the heaviest weight you are capable of, you should be lifting the least weight required to effectively load the muscles and thoroughly inroad them within a reasonable time. While it may seem counterintuitive, the better you are at an exercise the sooner you will fail with a given weight.

Don’t mistake being better at exercise for being better at lifting weights or being stronger. Beingbetter at exercise means being more skilled at using the weight to challenge the muscles, to make the movement harder. Being better at lifting weights means being more skilled at creating favorable leverages and using momentum to make it easier for your muscles to move the weight. Being stronger means being able to produce more force, not being able to lift more weight, because the manner in which you lift it makes a huge difference in how much force is required.

If you want to impress ignorant people in the gym, learn to lift weights in the easiest manner possible so you can load lots of plates on the bar and make all sorts of noise.

If you want to become as strong as possible, learn to use the weight to make the exercise as hard as possible to create a stronger stimulus for growth.”

Responses to email questions:

Weight vs. lever

A few people asked how this is possible with the same weight. It is because weight is only one of several factors affecting the resistance the muscles encounter during exercise, the force they must overcome to lift, hold, or lower the weight under control. Leverage, which is affected by body positioning and alignment and range of motion, is a major factor. Acceleration and velocity are major factors. The ability to focus on intensely contracting the target muscles is a major factor. Depending on the exercise and equipment used there are many more. Depending on how you use it, a given weight can be harder or easier to lift, as well as safer or more dangerous.

For example, consider the effect of leverage during a leg press or squat. Despite the weight pinned on the stack or loaded on the barbell being the same over the entire range of motion, the lower half of the range of motion of a leg press or squat is harder than the top half due to the differences in leverage. If you don’t believe me, try a few reps in only the bottom half of the range of motion, then try a few in the top half, keeping everything else (speed, turnarounds, etc.) as equal as possible. The bottom half is more difficult because the longer levers (moment arms) result in more resistance. Weight x lever = resistance (torque, actually).

The goal of proper form is to use the weight to create a a level and variation in resistance that is both maximally challenging to the muscles being targeted and minimally harmful.

How much weight

Enough that you are able to recruit all the motor units in the targeted muscles and achieve momentary muscular failure within about  90 seconds, or around 6 to 10 reps at a moderately slow speed.

If the weight is too light you’ll keep recycling the more fatigue resistant fibers and not recruit and effectively stimulate the larger, high-threshold motor units. If the weight is too heavy form tends to fall apart and injury becomes more likely, especially when approaching momentary muscular failure.

Speed and weight

Moving more slowly in and of itself does not reduce the weight you can use. Your muscles are actually capable of contracting with more force at slower velocities (do not confuse the velocity/force curve with the acceleration formula – they are two different things). Moving more slowly makes exercise harder because it allows you to better control body position and movement and levers and keep the tension on the targeted muscles, as well as improves your ability to focus on intensely contracting them.

Criticisms of rest-pause, negative-only, and “advanced” training techniques

This resulted in more email than anything else. There are numerous problems with each of these, all of which are discussed in Elements of Form,  and I’m not going to repeat all of it here, but the main issues are the misguided focus on mechanical work (total weight or reps) rather than intensity of effort and various safety problems inherent in repeated loading and unloading and intra or interpersonal resistance transfer compounded by progressive fatigue.

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