Ever wonder what is actually going on between your mind and your muscles during your strength training? How do you technically learn a new exercise or build strength from a neuromuscular standpoint? Let’s dive into the physiology behind your brain-body connection so you can use it to your advantage in your strength training.
Resistance training develops motor neuron pathways that enhance your brain-body coordination during functional movements.
The “neural adaptations” athletes undergo in training refers to the brain’s ability to recruit muscles to contract and produce a particular movement. Practicing an exercise with resistance teaches your brain to fire the correct muscles to achieve a desired movement. Over time, the athlete’s cadence and technique to the exercise also become engrained so that the movement seems more automatic.
To understand this adaptation, one must understand how motor neurons and muscle memory work.
Motor neurons are nerve cells that originate in the central nervous system (in the spinal cord) and end at the muscle fiber in a space called the neuromuscular junction. Signals sent from the brain run along the motor neuron to the muscle fiber to produce movement, or muscular contraction. Some motor neurons are devoted to autonomic functions like the ones that signal your diaphragm to contract to allow you to breathe. For our purposes, we are only concerned with motor neurons dedicated to voluntary movement, such as in strength training. With every new exercise attempted, the brain must send signals along motor neurons to the correct muscle fibers to contract.
Muscle memory, also known as neuromuscular facilitation, is the process by which the neuromuscular system memorizes motor skills, such that the signals from the brain to the muscle become semi-automatic, and you no longer need to concentrate so hard to create the desired movement because a pathway has been established through practice. It is likely that the muscle tissue itself also develops long-lasting changes (i.e. increases in fiber size and changes in fiber composition).
Functional strength training helps athletes develop muscle memory so that they can quickly access their movement patterns during performance. More complex movements involving the whole body demand greater muscle recruitment and more closely approximate the demands in each sport than isolated movements do. A deep squat will yield greater gain for an athlete than a biceps curl because the squat requires coordination among the hamstrings, hips, glutes, quads, core, and more to complete the movement.
Moreover, some trainers speculate that doing a strength exercise, like a deep squat, when the body is slightly fatigued will teach the brain to recruit muscles when it normally doesn’t. This adaptation would be useful at the end of a race, game or event, when your strength normally begins to wane. In general, athletes and coaches prefer to strength train “fresh” when glycogen stores in the muscle are readily available and the athlete’s range of motion is high. Thus, in the context of the neuromuscular system there is a cyclic nature to developing strength: teach the brain to fire correct muscles to contract with a new movement, add resistance, recruit more muscle fibers to oppose the resistance, build strength and adapt to the resistance, increase the complexity or resistance, etc.
Resistance Train the Smart Way
Given this understanding of the neuromuscular system, resistance training should take advantage of how the brain and body learn to build strength.
As much as overtraining is a red flag for athletes, it is easy to under-train without realizing it. If athletes do not perform an exercise with sufficient resistance, velocity of movement, or complexity, they may be developing muscle memory for an improper movement pattern. It would be as if you are grooving a motor pathway for a skill that isn’t powerful, fast, or complex enough. Because practice solidifies muscle memory, you should pay attention to how you execute your resistance training to develop the appropriate skills for your sport. Always make sure the following are in check:
Most of your resistance training will be conducted at 60-80% of 1RM (RM is the max resistance you can do given one repetition) 1. More qualitatively, you should be getting through 6-8 reps of a given exercise where the last couple reps are challenging, yet you are not going to failure. As always, technique takes priority over increasing your resistance. You want your muscles to memorize the right technique before you start adding more resistance, or you risk injury or developing the wrong muscles.
Sufficient Velocity of Movement
During each rep, athletes need to move through the exercise with sufficient velocity. You’re developing a highly neural pathway that will become more and more automatic, so you need to move deliberately and with speed to build movement patterns that are relevant to your performance. Athletes may need to go down in resistance to ensure they can move with enough velocity and the correct technique.
Whole body exercises are simply more functional. They more closely approximate the neuromuscular demand of movements in sports because they require coordination among several muscle groups to achieve a movement. Functional movements like squats, lunges, and pushups demand complexity and teach the brain to fire all the muscles necessary, whereas isolated movements only fire one muscle group at a time. Athletes should focus on full body movements to develop strength in the general strength phase of their season, and then simply maintain the motor pathways with fewer reps or rounds later in the season.
Bottom Line: Neural adaptations are happening all the time during resistance training. The brain sends signals along motor pathways to tell muscles when, how quickly, and how powerfully to contract to produce movement. Take advantage of your muscle memory and using sufficient resistance, velocity, and complexity to develop high-performance strength!
1. Episode 3: Strength training- Myths, misconceptions, and application for distance runners https://itunes.apple.com/us/podcast/magness-marcus-on-coaching/id961516002c