Category Archives: motor units
Training for maximum power requires you to recruit the high-threshold motor units. To recruit them, you must lift maximal loads (>85% of 1RM) or you must lift submaximal loads (50-75% of 1RM) with high acceleration so the actual lifting velocity is fast.
There’s a simple way to ensure that you get maximum power from each set: limit the duration of each set to 10 seconds or less. Why?
It has to do with the endurance capabilities of your high-power motor units. Your largest motor units are known as fast-twitch, fast-fatigable (FF) motor units that contain a large bundle of type IIb muscle fibers. Type IIb fibers have a very limited capacity of energy so they fatigue within 10 seconds. After you recruit the FF motor units, it’s tough to keep activating them because they don’t recover quickly.
However, the second most-powerful motor units come from the fast-twitch, fatigue-resistant (FFR) motor units that contain type IIa muscle fibers. Like all motor units, they range in size and endurance. You have FFR motor units with fewer muscle fibers that get activated before a FFR motor unit that’s any larger. In other words, you have FFR motor units that are bigger and stronger than others. The largest ones have the lowest endurance capacity. So by keeping your sets to 10 seconds, or less, you’ll target and develop the most powerful FFR motor units that have plenty of growth and power potential.
With heavy loads, this 10-second rule is easy to follow because you can’t go past 10 seconds, even if you tried. For submaximal loads, it’s much easier to screw up. As a gross generalization, shoot for three reps per set with submaximal loads.
For example, when you need to build explosive power, start with a load that allows around 20 reps. For those of you who like percentages, this is around 60% of your 1RM. Then, perform only three explosive reps for 10 sets with approximately 45 seconds of rest between each set. This ensures that each set lasts less than 10 seconds, the actual lifting velocity remains fast, and stay far away from failure. Remember, when you approach failure motor units start dropping out.
So whether you’re training heavy, or light and fast, limit the duration of your sets to 10 seconds and you’ll build new muscle and power fast!
Faster is better.
That’s one thing I’ve learned over the years. When physical prowess is the goal, moving faster is better than anything slower, provided you can maintain perfect technique. Now, an old person might be wise, but it’s likely he doesn’t move fast. Indeed, one of the tell-tale signs of aging is slowness.
Think about it. Boxers who lose their speed are relegated to a record with more losses and knockouts, as evident by Roy Jones Jr. When a basketball player is reaching the end of his career, it’s often said that he’s “losing his first step.” This is just another way of saying that he lost his speed. You can think of speed as being reactive ability, explosiveness, and the like.
One of the most important elements to building, and keeping, a youthful body is to move quickly. There’s plenty of research that supports the benefit of lifting fast, whether it’s for getting leaner, bigger, or stronger. And for strength and power development, research (Behm & Sale, 1993) shows that even the intent to move fast will make you a faster athlete.
In the gym, one of the simplest ways to get bigger, faster, or stronger is by accelerating your lifts as I explain in this video.
Speaking of what I’ve learned, this week the fitness world lost one of its pioneers, Jack LaLanne. I can’t say that I wholeheartedly agree with all of his mantras, but the guy maintained a youthful physique well into his 80s. You can’t argue with that. So out of respect for the man, here are three of my favorite pieces of wisdom from Mr. LaLanne.
“If man makes it, don’t eat it.”
“Scales lie! You lose thirty pounds of muscle and gain thirty pounds of fat, and you weigh the same, right? Take that tape measure out. That won’t lie. Your waistline is your lifeline. It should be the same as it was when you were a young person.”
“Go on, have a glass of wine with dinner. What is wine, anyway? Pure grapes. A glass of wine is much better for you than a Coke.”