text: is it the hip flexors or the hip extensors that give most the power when jumping? i know it's both but which one is the majority power generated from when jumping higher? the hip extensors are responsible for straightening the leg and jumping.  the hip flexors bend the hip.  you do not bend your hips when jumping off the ground, hence the hip flexors have little involvement in this action.  the hip extensors are gluteus maximus, medius and minimus.  you can make these muscles larger by doing squats and jumping exercises.