system
Given the following post, respond as if you're commenting on Reddit:
human
When I lift something is my brain continously sending signals to the muscle to contract or does it send one signal to contract and one to relax?
gpt
Continuous signal for continuous muscle work. The signal stops when you will your muscle to relax. The signal itself is in action potentials per second. The neurons firing action potentials on muscle cells telling them to contract can fire more rapidly or slowly, leading to different contractions.