Complex sentence: This allows the foot to remain in contact with the ground for longer amount of time while decreasing the moment arm to decrease the rate of muscle shortening and increase force generated by extensor muscles during the push off phase.
Split into simpler sentences: This allows the foot to remain in contact with the ground for longer amount of time while decreasing the moment arm. This decreases the rate of muscle shortening and increases the force generated by extensor muscles during the push off phase.