Exercise Setpoint - Jerry Robinson (1989)

Jerry Robinson founded and served as CEO of Health for Life, before moving on to co-found 
Dakim Brain Fitness, a unique brain training protocol.

Push it harder! 

Up that bench press by 10 pounds. 

Pile on another 25 for squats! Do more! 

Do still more!

Is this the attitude required for bodybuilding success? To put it another way -- does constantly striving to increase the number of reps and pounds lifted always make for maximum gains? And if not, what does?

We're going to answer those questions this month by exploring some of the adaptations that underlie increased body mass and strength.

Two Important Changes

The weight training formula most bodybuilders use to put on mass (3-5 sets of 6-8 reps per exercise) is very similar to the weight training formula other types of athletes use to develop muscular strength.

This sort of regimen causes a number of changes in the body. Of these, two are most important: 

1) improved nervous control of muscle; and

2) increased muscle fiber size. 

Let's consider each of these individually.

Nervous Control

 There are a lot of muscle fibers in a muscle. When stimulated, individual muscle fibers always contract as violently as possible. A single fiber cannot vary its contractile intensity relative the the load against which it is acting. To compensate for the wide variety of possible load conditions (playing the piano obviously doesn't require the same output as lifting weights), the central nervous system stimulates exactly the amount of fibers necessary to perform the job at hand. 

There is a limit, however, to the number of fibers you can call upon at a given instant. And this limit puts a ceiling on your strength.

Strength training increases the number of fibers you can voluntarily contract. This improvement in ability to recruit muscle fibers is what's primarily responsible for the dramatic increases in strength most athletes experience during their first six months of lifting weights.

Note that this change just involves your nervous system -- it doesn't involve physiological changes in the muscle itself. Indeed, improved recruitment is how some small individuals get to be as strong as some large individuals without getting any bigger.

In summary, the first important adaptation caused by strength training is increased recruitment of muscle fibers. More fibers recruited means more available "strength." This adaptation is purely neurological -- it does not involve any change in the physical appearance of muscle. 

Increased Fiber Size

 The second adaptation that occurs as a result of strength training is an increase in the cross-sectional diameter of muscle fibers. More specifically, what increases is the amount of contractile proteins in the myofibrils -- the component of muscle fibers that actually does the contracting. Having a greater quantity of the contractile proteins increases the potential tension a muscle can achieve when stimulated by the nervous system.

Clearly, increased fiber size does affect the physical appearance of muscle. The degree to which it contributes to your increases in strength is determined by a number of factors, including sleep, level of life stress, diet, and, of course, the way you approach your workout.

You're In Control

There are two important concepts here. The first is the distinction between the neurological and physiological adaptations to strength training.

The second is the idea that you have control over the relative contribution of those two adaptations. Depending on the way you work out, you can stimulate more neurological adaptation and less physiological adaptation (greater fiber recruitment, less size increase), or more physiological adaptation and less neurological adaptation (less fiber recruitment, but greater size).

The optimum workout calls for maximum physiological adaptation, preferably with minimum workout effort. Surprisingly, the attitude illustrated at the top of this article (more . . . more . . . more) is the exact opposite of the attitude necessary to achieve this goal. Here's why.

If you constantly push to lift more weight, never relenting in your quest for additional plates, neurological adaptation will (usually) outpace physiological adaptation.  

And, once you have adapted to a higher workout intensity based on the neurological ability to lift more weight, you will find that if you back off to a lower intensity level (for example, to an earlier version of your program with less weight or fewer sets), your muscle mass will stop increasing. 

There's no mystery why this is so. Having adapted to an intensity level associated with greater neurological strength, working at a lower intensity no longer represents sufficient overload to stimulate growth. 

And there's the rub: In this scenario, you have raised your threshold for gains. And you have done so with no increase in body mass!

Generally speaking, if you keep increasing your strength through neurological adaptation -- brought on by continually increasing number of exercises, pace, and amount of weight you are lifting -- and you don't allow your body mass to increase as much as possible for a given training intensity, you're stuck! You will be forced to train at or above the new elevated level to achieve any increases in mass.

That means the mass increases you could have achieved training at a lower level (less time, less effort), you will now only be able to achieve training at a higher level (more time, more effort).

The bottom line is that if you are trying to increase muscle mass, allow your body to stabilize at a new weight whenever you increase the intensity of your training. Don't be quick to bump up weight, pace, and number of sets, or you waste both energy and time!

Likewise, if you are training to increase definition, stay with a particular workout intensity level until you stop seeing improvements. If you are quick to add new exercises and do more reps, you will have to keep doing those new exercises at that increased number or reps to see any substantial improvement in definition.

Anything less will not represent an overload to the target muscle or muscle group and will not trigger the desired adaptive response.

In Review

For a given training intensity (combined effect of amount of weight lifted, pace, number of sets per body part, and mental focus), you can achieve a certain increase in muscle strength, endurance and bulk.

Working at a particular exercise intensity limits your ability to increase muscle mass, endurance and strength training at a lower intensity.

If you continually increase workout intensity without allowing your body to realize the maximum gains possible at each training intensity level, you force yourself to work much harder than necessary to achieve your goals.