Muscle strength is best defined as the maximum amount of force that the muscle can produce. That’s called the force of maximum voluntary contraction, or MVC.

The force you can generate with a maximal voluntary contraction depends on the number of individual muscle cells (called muscle fibers) that fire off as part of a coordinated movement action.

When you gain muscle mass, you’ve got more muscle fibers, so potentially you should be able to generate a larger force.

But it ain’t necessarily so.

That’s because individual muscle fibers don’t all jump in and fire off simultaneously. That would backfire, because your blood supply couldn’t bring in enough energy to sustain muscle contraction, and your muscle would cramp up. Or the overall muscle would quickly fatigue.

Instead of all hands on deck immediately, your body chooses a particular recruitment strategy. A recruitment strategy will bring different muscle fibers into play in a timed sequence, favoring certain types of muscle fibers over others, and rotating different fibers into and out of activity. The goal is to optimize your response to a specific movement challenge.

Two ways you can gain strength

Any exercise plan that works your muscles close to their threshold will trigger two strength-enhancing adaptations:

• You’ll build more muscle fibers, and
• You’ll have available as an option a recruitment strategy that fires off a higher percentage of your muscle fibers at the same time

But specific exercise strategies target one type of adaptation over the other.

If your goal is to gain muscle and lose fat, you want to build more muscle fibers. The benefits of gaining muscle mass go beyond just being stronger. There are also metabolic and hormonal benefits to healthy muscle tissue. Plus, the more muscle you have, the higher your resting metabolic rate is, so even when you’re at rest, you’re still burning more calories, enhancing your rate of fat loss.

What’s the best exercise plan to gain muscle mass?

To activate your muscles close to their maximum threshold, you have two basic choices:

1.  Use the greatest possible weight (or resistance) and max out after doing only qui1-3 reps.

This will enhance your muscle fiber recruitment strategy.

2.  Or use lesser weight (or resistance) that allows you to max out at 8-12 reps. This will enhance muscle tissue gain.

That’s what you want. You should choose a level of resistance so that your muscles hit a fatigue point after 8 to 12 reps.

Dr. Lavine has been an innovator in the use of movement and touch to promote health since 1981. He practices in New York City and Princeton, NJ.