i dont know you should look that one up
60-100 beats per minute
60-75ish per minute
A muscle becomes shorter when it contracts.
A muscle that contracts shortens whereas a muscle that relaxes lengthens.
When one muscle in a pair contracts the other expands.
Flexion
shortens
Flexion
shortens
The muscle that contracts when the leg is extended at the knee is call the gastrocnemius muscle
When the bicep contracts the triceps relax
Relaxes
When the muscle contracts, it gets shorter. When it relaxes, it gets longer.