May 28th, 2011
Mark Rippetoe coaching the deadlift at Eastside S&C in Redmond, WA
Many people are resistant to the idea that increases in bodyweight may be necessary to get stronger. There are many examples of athletes that perform amazing feats of strength at very low body weights. Many of these athletes did a good job of choosing their parents and may be capable of these feats because of how their nervous system interacts with their musculature. Let’s discuss that.
There are two primary ways in which a trainee can get stronger. The first involves making the nervous system more effective at firing muscles. When a trainee lifts a weight, motor neurons send the signal to a group of muscle fibers to contract. A motor neuron and the muscle fibers it innervates are called a motor unit. As far as we understand it, when a motor unit is turned on, it contracts at full strength. More force is produced when more motor units contract at the same time. A trainee that can recruit large numbers of motor units at the same time is going to more fully realize their potential to generate force. They possess high levels of neuromuscular efficiency.
Neuromuscular efficiency, like most physical traits, responds to training. In an untrained individual, neuromuscular efficiency is probably low. These trainees will see rapid strength gains in strength once they start lifting. They can get stronger without putting on much weight because they are training their bodies to use the resources at their disposal more effectively.
Like most good things, these gains do not continue indefinitely. After several months of training, many of the easy neurological improvements have been made. A trainee can still become more efficient, but the gains come from an increasingly small slice of the pie. This is when we need to look to the second method for increasing strength – finding ways to make the muscles contract with greater force. That’s a topic for another day.
Before we call it quits, however, I want to return those individuals who are able to be both very light and very strong. Keeping neuromuscular efficiency in mind, we can surmise that these people have nervous systems that are well plugged in to their muscles. At the cellular level, they may also have contractile proteins that generate greater force than other people, but for the sake of simplicity, they are neuromuscularly efficient. How can you identify these people quickly and easily? Ask them to perform a standing vertical jump. Those that jump the highest will be the ones that tend to excel at athletics. There are, of course, exceptions to that, but a vertical jump is a nice easy field test to determine how efficient a trainee is at recruiting motor units.
While we can get better at using what we have, there is no real way to increase the level of innervation of the muscles in adults. Those kinds of the things are set into motion during fetal development. If you don’t have a 34-inch vertical jump, what can you do when you want to get stronger? We’ll discuss that in the next installment.