How do the muscles know when to activate?

The nervous system sends signals directly to muscles. Some muscle contractions occur without us consciously thinking about it (like blinking, breathing in general, pulling our hand away from a hot stove). In regards to exercise, the body movement goal is decided by us, then the nervous system does its best to send signals to the correct muscle groups (and at the same time inhibit other muscles that aren’t supposed to activate) so the action can take place. Sometimes the action we want needs practice, which means the nervous system signaling can be refined to accomplish more efficient movement. For example, there is a common muscle activation dysfunction called “dumb butt syndrome”. It simply means that an individual has poor muscle activation in their glute muscles, which are a large and very important muscle group used for walking, climbing stairs, standing up out of a chair, squatting, etc. Many daily activities of living and sports movements depend on the glutes to do their part! Lack of glute activation can mean other muscles are over engaged and the body becomes unbalanced and inefficient. Inactive glutes can often result in knee and low back pain or injury. Glute activation can be practiced with proper exercise technique and conscious effort of the individual performing the movements.

Muscles generate a lot of heat when activated. Sweating is how the body dissipates this heat. It is important to be well hydrated before exercise and re-hydrate after. Depending on the type of exercise, duration, and intensity, you may want to consume some water as you go. If you exercise while you are dehydrated, your performance will be affected. The body will have to work a lot harder to continue to exercise and you will tire more quickly. Revisit the Fuel for Exercise section found under Getting Started and review water intake recommendations.