Muscles and nerves adapt to physical challenges to make higher intensity efforts easier in three ways: better effort coordination, higher demand signaling, and

Muscles and nerves adapt to physical challenges to make higher intensity efforts easier in three ways: better effort coordination, higher demand signaling, and higher force produced by muscle fibers. (We tend to think of just the latter, but all three significantly impact “strength”.) Each of these has mechanisms of maintenance and faster recovery after use lapses. Which can all be described as memory. First, the spinal cord and motor cortex learn more effective coordination. Proper coordination of muscles impacts strength by ensuring our different muscles cooperate effectively to apply force where we need it. We imagine simple movements as simple efforts, but they are really a series of coordinated multiple muscle response. This can be considered “normal” neural/cognitive learning and memory in the brain, spinal coord and nervous system. Second, our nervous system learns to send higher intensity demand signals to the muscles. I don’t know what the mechanism is here. Maybe higher coordination of simultaneous signals within the muscle? Maybe an increase in signal strengths? An increase in nerve cells? A combination? In any case, once learned, this learning is mostly maintained despite loss of stimulus and relearned quickly. This creates a common source of injury. After a workout hiatus, our ability to demand intense muscle response can exceed the abilities of our reduced muscle’s capabilities. It can feel too easy to push our bodies hard again, resulting in injuries that abort the attempt to restart training. Restart weight lifting programs with patience and caution, until muscles catch up with the renewed overload, hypertrophy and recovery cycle. The third very long term memory mechanism in muscle cells is quite interesting: myonuclear accretion. Support cells merge with muscle cells permanently giving them multiple nuclei, permanently increasing their ability and speed to create the proteins we need for hypertrophy (muscle growth) and recovery (repair and energy store recuperation). Myonuclear accretion allows muscle cells to grow far beyond their original limits. And accounts for why previously trained muscles can retain a modestly higher level of strength and size, even after training regimen lapses. All three memory mechanisms account for why regaining previous high levels of strength happens faster, with less effort, than it took to gain any level of strength the first time. Aother memory mechanism include higher interoception, prioperception, kinematics, and higher level learning regarding exercise form, workout discipline, workout organization, body limitations, injury warnings, positive associations with making effort, etc. that are all result in long term increased strength and ability recover and accumulate it.