Going up the stairs requires a function of which three body systems

1. Skeletal

2. Muscular

3. Nervous

When you walk upstairs you engage numerous muscles, including the hip flexors - - iliopsoas, sartorius, rectus femoris, tensor fasciae latae and pectineus - - in your hips and thighs; the gluteus medius on your outer thighs; the gluteus maximus in your behind; the quadriceps group in the front of each thigh; and your hamstrings.

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