As Pilates instructors we love to analyse movement through muscle and joint action, to assess restrictions and compensations and use our findings to help exercise prescription. In analysing movement we must consider the relationship of the movement to gravity. In Matwork the main source of external resistance is gravity, unlike the Studio Equipment where resistance comes from springs. So to explain, if the joint moves against gravity then the muscle group that causes the action will work concentrically (shortening as they generate force). If the movement follows the same direction as gravity then the muscle group that has the opposite action will contract eccentrically (lengthen as they generate force).
In the first phase, as the spine flexes to roll up, it moves against gravity therefore the rectus abdominus and hip flexors contract concentrically, whereas in the second phase as the spine returns to the mat it moves in the same direction as gravity so the rectus abdominus and hip flexors work eccentrically controlling the movement.
Changes in the relationship to gravity means changes to muscles functioning. For example, moving from a supine position to standing as in the The Push Up where the first phase is the roll down. Here as the spine flexes forwards caused by gravity, it is the back extensors which are contracting eccentrically to control the movement not the rectus abdominus, and then contracting concentrically as the spine returns to standing.
Many of the Matwork moves are complex and so the effects of gravity during the movements will produce different types of contraction and muscular emphasis. The Roll Over illustrates these changes perfectly as we consider the leg movement.
To lift the legs up to ceiling the hip flexors work concentrically but as they pass the vertical position gravity will cause the hip flexion so the hip extensors are used to control the leg position. On the return, once the pelvis is on the mat, gravity creates the hip extension to lower the legs and so the hip flexors work eccentrically to control the lowering.
When analysing Pilates movement always try to consider this fundamental relationship between the key body segments and gravity at each phase of movement. Try now to analyse Hip Twist- let me know if you have any questions!