Knickerbocker's theory emphasizes on the interdependence of major players in the same industry. Imitation is the name of the game where firms try to match each other's moves to keep each other in check so as not to allow a rival gain a competitive advantage over others.
hamstrings. extend the hip and flex the knee against resistance and are important knee stabilizers. help control hip flexion in weightbearing position by contracting eccentrically when the flexion occurs in same direction as gravity as dead lift or hip=hinge position.
The hip extensors work in a vertical jump to extend the hip after the initial squat. These muscles include the gluteus maximus and the hamstrings. Of these muscles, the gluteus maximus has the most impact on the jump. The hamstrings are two-joint muscles. In addition to extending the hip, they work to bend the knee.