Studying muscle anatomy and their individual actions is a lot to know understand. It’s a significant amount of information. But this is just the beginning. In reality, when helping real people, you have to be able to apply these concept. You have to know what muscles are being recruited when performing specific movements or exercises...and what exercises to perform when you want to train a particular muscle or muscle group.
Taking this a step further, you must understand when concentric and eccentric muscle actions occur during an exercise for the muscle/s being trained. A concentric muscle is the active shortening of muscle. During this contraction, the muscle is producing force to overcome the external resistance. With an eccentric muscle contraction, there is active lengthening of a muscle. At this time, the external resistance is greater than the force being produced by a muscle.
This is not ALWAYS the same as the upward and downward phase of an exercise. In many instances, they are the same, but again...not ALWAYS.
Want to get better at understanding when you are performing a concentric vs eccentric muscle contraction? Perform any exercise. Do it yourself. Feel the difference between concentric vs eccentric. Comment below on what exercise you tried, and when the concentric and eccentric muscle contractions occur⬇️