Can Imaginary Exercise Make a Pitcher Better?

| Research
Reading Time: 7 minutes

I won’t bury the lead. The answer is yes, it is highly likely that imaginary exercise can make a pitcher better.

In the early 90s, several researchers set out to test the efficacy of pure imaginary exercise on the strength of a finger [1]. (The finger was chosen because it has small muscles that are easy to test and isolate.)  The researchers had three groups of subjects: group 1 performed actual finger exercises, group 2 performed no finger exercises, and group 3 simply imagined the finger exercises performed by group 1.

After 4 weeks, the results were pretty incredible.

As expected, the subjects in the first group (the subjects that completed the actual exercises) increased the strength of the exercised finger by 30% on average. Also as expected, the subjects in the second group did not substantially increase the strength of the finger.

Now here’s the incredible part… the subjects in the third group, the subjects that only imagined exercises without actually activating muscles, increased the force output of the “exercised” finger by 22%.

Pure imaginary exercises significantly increased the force output of the tested finger muscles. In the imposed experimental protocol, the muscles did not get bigger and stronger… so what happened?

With the imaginary exercises, the subjects’ nervous systems became more effective at accomplishing the desired task. Their brains learned to more effectively activate the targeted muscles.

How the Nervous System Activates Muscles

The nervous system is made up of the brain, spinal cord, sensory organs, and nerves. This system is essentially the controller of the body. It turns the muscles on when they need to be on and off when they need to be off.

To turn a muscle on, the brain generates an electrochemical signal that travels down the spinal cord and into the desired muscle through a nerve. This signal is called an action potential [2].

One action potential does not turn on a whole muscle. One action potential activates a small group of muscle fibers, called a motor unit, within a muscle [2].

As I mentioned previously, one muscle is made up of many muscle fibers. And each muscle fiber has different speed, strength, and endurance characteristics. The fibers that contract more slowly are generally weaker and more resistant to fatigue. The fibers that contract more quickly are typically stronger and more susceptible to fatigue.

Muscle fibers are organized into motor units of similar size, speed, strength, and endurance characteristics [2].

The initial action potentials sent from the brain to a muscle turn on the slowest and weakest motor units in the muscle [2]. As the brain sends more action potentials at faster speeds and frequencies, more motor units get turned on to participate in the desired muscular task. In general, each additional motor unit that gets recruited is bigger, faster, and stronger than the previous one.

Moreover, motor units are not recruited one at a time. They add up [2]. The bigger and stronger units are added to the smaller and weaker ones to generate a more powerful muscle contraction. This is known as the size principle.

Conversely, if the brain does not send action potentials at fast enough speeds, the faster and stronger motor units are never activated. They are never recruited and only the slower and weaker motor units participate in the desired task.

So what causes the brain to send more action potentials at faster speeds to recruit the most powerful motor units in a muscle?

Why Intent Matters in Pitching Training

It is the level of exertion, or intent, which determines the amount of motor units recruited to perform a task [2].

Increased intent may help explain how imaginary exercise can increase muscle force output. Imaginary exercise seems to teach the nervous system to perform a task with greater intent, facilitating the recruitment of more powerful muscle motor units.

The level of exertion, or intent, with which an athlete performs a task, is determined by the athlete’s level of focus and effort. Imaginary exercise can improve both.

However, despite the effectiveness of imaginary exercise, I am not advocating that a pitcher should skip the training room and just visualize pitching in the big leagues. As demonstrated by the finger experiment described above, a training regimen that exercises both the nervous system AND the musculoskeletal system is most effective.

Want to get started training with intent? Driveline’s Starter Kit has a simple, effective program to get you started.

Simple Training Techniques to Fire Up the Nervous System

So here’s the take-away message for pitchers and really all athletes:

Physical exercise should always be accompanied by mental exercise. Never go through the motions. Always try to complete the task you are practicing with greater intent.

When throwing a bullpen, a pitcher should throw each pitch like it’s the ninth inning of a one run game. During long toss, a pitcher should focus on generating power that will translate to the mound. When practicing with a heavier ball, a pitcher should focus on learning the feeling of throwing the heavier object with maximum efficiency. And the list goes on…learn the goal of a drill and then focus on completing the goal.

Practicing with greater intent will lead to nervous system adaptation. Over time, the nervous system will learn to activate more powerful motor units.

For pitchers, activating more powerful motor units leads to better performance, typically in the form of increased velocity.

One way to start practicing with greater intent is to try an unfamiliar exercise regimen. An unfamiliar task requires more focus and thus typically engages the nervous system to a greater extent. For this reason, it is beneficial for pitchers to mix up their training programs and try new things.

A training program only composed of long toss will not be nearly as effective as a program composed of many different training modalities.

Theoretical Implications for Rehabbing Pitchers

Rehabbing athletes who are unable to complete physical exercise should especially take advantage of the adaptability of the nervous system. For example, a pitcher who is recovering from Tommy John surgery can effectively mentally practice his or her windup before ever touching a baseball. Even imaginary biceps curls or shoulder rotations may speed up post-surgery recovery.

And if pure imaginary exercise is too difficult, a rehabbing pitcher can try exercising his or her non-dominant arm. Studies have shown that exercising the non-dominant arm increases the strength of the dominant arm, or vice versa, through similar neural adaptation mechanisms [2].

It is easy to neglect nervous system exercise. It doesn’t make you sweat or cause a muscle to swell. But this system, made up of the brain, spinal cord, sensory organs, and nerves, determines how much of your muscle capacity you use.

Therefore, it is critical to give the nervous system as much attention in training as the musculoskeletal system.

An athlete who uses 90% of a weaker muscle can be just as effective as an athlete who uses 30% of a stronger muscle. And neither athlete will be as effective as the guy or girl who uses 90% of the strongest muscle.

Interested in more of how intent shapes your training? Hacking The Kinetic Chain is a complete training guide for building better pitchers.

Dr. James H. Buffi has a degree in mechanical engineering from the University of Notre Dame and a PhD in biomedical engineering from Northwestern University. His doctoral dissertation was called, “Using Biomechanical Modeling and Simulation to Calculate Potential Muscle Contributions to the Elbow Varus Moment during Baseball Pitching.”  He has also been a visiting scholar in the National Center for Simulation in Rehabilitation Research at Stanford University as well as a visiting researcher at Massachusetts General Hospital. You can follow @jameshbuffi on twitter.


  1. Yue, G. and K.J. Cole, Strength increases from the motor program: comparison of training with maximal voluntary and imagined muscle contractions. J Neurophysiol, 1992. 67(5): p. 1114-23.
  2. Lieber, R.L. and R.L. Lieber, Skeletal muscle structure, function & plasticity : the physiological basis of rehabilitation. 3rd ed. 2009, Philadelphia: Lippincott Williams & Wilkins. xii, 369 p.

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