The Benefits Of Gym Workouts – Five Healthy Reasons

In the four part series “Intensity or Effort – Which is it?” we reviewed the relevant research on intensity and effort to determine which one elicited the most muscle activation.  For our purposes intensity is a measure of the amount of weight being lifted (i.e. how heavy the weight being lifted is in comparison to the maximum amount of weight that could be lifted for 1 repetition) while effort is an expression of the level of exertion (i.e. how close to “muscle failure” you are at the end of a set of an exercise).

There has been considerable and heated debate over this topic in the strength training world.  Some have strongly argued that the amount of weight being lifted is basically immaterial as long as the effort being exerted is maximal or near-maximal.  Others hold an equally strong, but opposing, belief that stimulating maximum muscle growth requires near-maximum weights (i.e. 3-5 reps).

An unbiased analysis of all the research indicated that when it comes to maximum muscle activation intensity is the more important factor.  Training with heavy weights and low reps activates more muscle fibers than training to failure with light weights and high repetitions.

Is the debate settled?  Can you just go to the gym, lift heavy weights for low reps, and stimulate maximum muscle growth?

Perhaps.

But perhaps not.  In fact, I suggest the whole argument over intensity or effort is an argument about the wrong thing; debating which is more import is sort of like arguing over the arrangement of the deck chairs on the Titantic.  It’s not the right thing to be concentrating on.

Why would I say that?  Let’s talk about it.

We begin by establishing a couple of facts.  First, in order to train a muscle fiber that fiber has to be activated.  Inactive muscle fiber are not stimulated and, therefore, don’t increase in strength or size.  That simple but critical fact is at the heart of the intensity or effort debate.  If you want to get bigger and stronger then you have to activate as many muscle fibers as possible.  And since your goal is to activate as many fibers as possible you want to know what method is the most effective for activating muscle fibers.  Hence the whole intensity or effort debate.

However, while activating a muscle fiber (or more properly said, a motor unit) is necessary for muscle growth it is insufficient for muscle growth.  What does that mean?  It means that merely activating a muscle fiber won’t cause that fiber to get bigger or stronger.

Bringing us to our second important fact – muscle fibers have to be trained to the point of fatigue (trained to failure or near failure) in order to provide sufficient stimulus.  Merely activating a fiber won’t cause it to get bigger or stronger.  Activating a fiber and then working it to the point of fatigue is required in order to cause the fiber to adapt and grow.  That’s why I suggest the “intensity or effort” debate is focusing on the wrong thing – neither one addresses the imperative that muscle fibers have to be both activated and fatigued in order to stimulate growth.

Clearly both intensity and effort are required in order to stimulate maximum muscle growth.  First you have to activate a muscle fiber via intensity and then you have to train that fiber to the point of fatigue through effort.

That’s not a surprising revelation though – strength training lore has long preached that you have to train with relatively heavy weights/low reps (somewhere between 2 and 20 reps) and high effort (to failure or near failure) if you want to maximize muscle growth.

But even that misses a most critical fact.  And by missing this critical fact, traditional strength training programs are less effective than they could be.  The strength training program you are using right now is not working as well as it could be due to fact that it doesn’t account for this critical component.

The critical missing fact is muscle fibers fatigue at different rates.

Your muscles (biceps, triceps, pecs, etc) are composed of different types of muscle fibers.  Depending on which research you chose to believe to you have 3 or 5 (or 6 or 9, etc) different types of muscle fibers.  The traditional classification says there are three types of fibers – slow twitch, fast twitch A and fast twitch B.

In any case, no matter how many different types you have, they all fatigue at different rates.  Some fibers (the fast twitch B ones) fatigue very rapidly, tiring between a few seconds and about 1 minute.  Fast twitch A fibers can work from 1 minute to about 5 minutes before fatigue sets in.  Slow twitch fibers can take hours to fatigue.

Which brings us to this – in order to effectively train a muscle fiber you have to work that fiber for a long enough period of time to fatigue it.  If a fiber takes 1 minute to fatigue and you only work it for 30 seconds then that fiber won’t receive a maximum stimulus.  If a fiber takes 2 minutes to fatigue and you only work it for 1 minute, it will be sub-optimally trained.

If your goal is maximum strength or size then you need to optimally train as many of your fast twitch fibers as is practical. 

How do you do that?  By training to failure or near failure using a rep range of between 3 and 40 reps; a range of reps that will take between 6 seconds and 120 seconds, which is the range of time it takes to fatigue most of your fast twitch fibers.

Do some sets with a weight so heavy that you can’t do more than 3-5 reps.  Do other sets with a weight that limits you to 10-12 reps.  And do a set or two with a weight that allows you a maximum of 20 reps.  Finally, do a set of 35-40 reps.  By doing such a wide range of reps you will be training as many fast twitch fibers as is practical to do.  And you will gain as much strength and size as you are capable of.

Most programs fail to account for the varying rate of fatigue for different muscle fibers, a point emphasized by the whole intensity or effort debate. Neither intensity or effort take into account the fact that different fibers fatigue at different times.  It is also evident in the single set versus multiple sets argument.  The multiple set advocates limit the trainee to a narrow rep range (usually between 3-15 reps) and the single set group limit the trainee to one rep range (also usually between 3-15 reps).  In both cases – intensity or effort and single versus multiple sets – varying rate of fatigue is simply not considered as a critical training factor.

So, while the research indicates that intensity is the factor most influential in determining how many muscle fibers are activated, it’s the wrong thing to be focused on.  Instead, I suggest that we should focus on activating and then training to failure as many fast twitch fibers as is practical.  To do that requires acknowledging and making provisions in our training programs for the varying rate of fatigue of different fibers.  Activate them and then train them to fatigue – anything less is sub-optimal.