Hamstring squeeze. Use the machine that works your hamstrings; you will either lie on your stomach or sit with a pad behind your knee. Push against the pad, moving your knee up toward the ceiling or backward (depending on which position you’re in). “In other words, bend your knees,” Pariser says. But to avoid cramps in your hamstring muscles, don’t bend your knee so much that your heels are too close to your buttocks.
During pregnancy a woman’s abdominals get stretched out. There is no way to avoid this with a growing baby. Muscles work most effectively when they are at an optimal length. Not too short and not too long. The lengthening that happens during pregnancy puts the abdominal muscles at a decreased advantage for working. This decreases the amount of support they provide for spinal stability.
A sedentary lifestyle can lead to having weak and tight hip flexors as they are always in the shortened position. Tight hip flexors can lead to a limited range of motion, poor posture, lower back and hip pain, and even injuries. These muscles need to get a workout when you are standing and doing movements such as raising your leg to climb stairs, run, or ride a bicycle.