There are three main types of muscle contractions:
eccentric
concentric
isometric
Eccentric contractions are lengthening movements of your muscles.
Examples of these are:
walking
lowering a dumbbell
calf raises
squats
triceps extensions
A concentric contraction is a type of muscle activation that causes tension on your muscle as it shortens.
Examples of these are:
lifting objects
bicep curl
extending from a pushup
standing from a squat
hamstring curls
situps
Isometric movements are muscle contractions that do not cause your joints to move. Your muscles are activated, but they are not required to lengthen or shorten. As a result, isometric contractions generate force and tension without any movement through your joints.
Examples of these are:
plank holds
The muscles of the arms when holding or carrying an object in front of you in a steady position
holding a dumbbell weight in place halfway through a bicep curl
bridge holds
wall sits
Continue reading: https://www.healthline.com/health/concentric-contraction