Muscle Memory

In addition to the back and forth communication between brain and muscle, and muscle and brain, other areas of the brain can influence our physical activity. For example, observing another person’s physical action in your brain’s visual center can actually stimulate your own motor cortex to prepare your muscles for the same action—even without you moving. This is called action observation and is associated with stored memories called engrams. This “motor memory” is the basis of the various mental imagery techniques used in sports training. Watching a swimmer who has excellent technique can help you swim more efficiently because your brain has been programmed, through visual input and memory, and your motor area now knows how your muscles need to act. Unfortunately, there are still other areas of the brain that can influence the same memories and actions, including past training where you may have learned incorrect swim technique. So while this can be helpful for many athletes, it’s not a perfect training tool for everyone. Watching a marathoner with a great physique and stride may appear like something to imitate, but trying to do that with a body not prepared to run the same way can quickly lead to excess stress on the muscles and joints, and even injury.

Such was the case with Kim, a young distance runner who showed great potential in college. During her summer break she attended a running camp where she was videotaped. The footage, played back in slow motion, accentuated her seemingly imperfect running gait. After being told to lengthen her stride and exaggerate other motions, such as lifting her knees and swinging her arms more like a 400-meter runner, she became very sore after each workout. Within about two weeks, she had leg pain that required days off from training, and eventually knee and hip pain that rendered her unable to train at all. This is when I first saw Kim in my clinic. After hearing her history, and performing an examination, it was clear that the first step was to restore normal communication between the brain and muscles. This was easily accomplished with biofeedback—a technique that corrects dysfunction of injured muscles by encouraging brain-muscle and muscle-brain communication. More importantly, Kim was instructed to stop overstriding and exaggerating her gait, and instead, just run relaxed and allow her brain to dictate the motions. Within a week, the pain was gone and Kim was running again without mechanical problems.

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Because the brain remembers everything it experiences, be careful what you put into it. Kim had to unlearn trying to run like a sprinter. In cases of retraining, it sometimes takes a period of adaptation during which you may feel physically inadequate or even experience a falloff in performance until your brain-muscle mechanism gets back in sync.

This was what happened to Sam, a triathlete who I observed swimming laps in the pool. Swimming was his weakest event. One look at Sam in the pool showed why—his technique was poor, and he swam quite irregularly because of a one-sided head-turn and other asymmetrical movements. By improving muscle function, and with the help of a swim coach, Sam was better able to understand correct mechanics, and made great improvements over the following two months. However, this period was in the middle of Sam’s racing season, and during this transition to better mechanics, his swim times worsened. Sam could not help going back to his more comfortable improper swim patterns during a race, but in time, as he trained his brain and body to follow better technique, he performed significantly better. Ultimately, his swimming became as strong as his cycling, which was his strongest event.

In summary, proper training includes programming your brain, muscles, metabolism, and all other areas of the body. Training the nerves that attach to the aerobic muscles is key for developing optimal endurance through better fat burning. But you have to stimulate all of these muscles, beginning with the smallest and slowest ones. Over time, as these nerves and muscles are properly trained, they work more efficiently. The result is they’ll be able to do more work with the same effort, which translates into more speed.

The brain also plays a role in muscle balance, and adapts the body to muscle imbalance to prevent further injury. Muscle balance is the sum of muscle contraction and relaxation. Muscle imbalance occurs when one muscle group in the front of the thigh—for example, the quadriceps—contracts too much and is tight, and the muscle group on the back of the thigh, the hamstrings, contracts too little and becomes weak. This pattern is a common cause of physical injuries and may be one of the most important factors contributing to fatigue during training and competition. The brain’s role is to sense these potential problems, make corrections, and compensate.