What is the Concentric Phase of Movement?
The concentric phase of a movement is the lifting phase. For example, in a shoulder press, it’s the phase from the racking position into the overhead position, it goes up. In a squat, it’s the phase from the bottom of the squat into the standing position, going up.
The kettlebell is moving away from the earth in the concentric phase, and this applies to any weight used, even body weight. In a bodyweight squat, the weight is moving away from the earth.
Gravity is an invisible force that pulls objects toward each other. Earth’s gravity is what pulls objects to the ground. Any time you go against that it’s considered a concentric phase.
During the concentric phase, the prime movers and the synergist muscles shorten and contract to act upon a joint. This action creates a movement against the force of gravity.
In the concentric phase, muscles are in a long state and then shorten under concentric contraction. The contraction decreases the angle in a joint and moves a load against gravity, away from the earth.