good morning

The good-morning is a weight training exercise. It is known as a good morning because of the movement in the erector spinae which resembles the bow that traditionally begins a schoolday in some East-Asian countries. The erector spinae muscles of the lower back work isometrically to keep the spine in an extended position while the hamstrings and gluteus maximus work isotonically to perform hip extension. Other muscles are involved in stabilizing weight on the back and maintaining balance.
The degree of knee bend used will change the focus. The straighter the knees, the more the hamstrings are stretched and stressed by the movement and this stretch involves them more as the hip extensors. Bent knees can shift the weight forward, which allows the pelvis to drift back further as the body hinges in hip flexion.

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