Fitness walking is first and foremost a workout for your legs and helps strengthen your thighs, glutes and calves.
How do these muscles work? At the front of the thigh, the quadriceps stretches the leg and bends the thigh at the hip. At the rear, the hamstrings enable the knee to bend and rotate and the femur to extend: they contract each time you fold your legs.
Glutes are the most powerful muscles in the body. Genuine stabilisers, they enable us to stand upright and thus prevent falling! They are particularly worked when walking, especially at a brisk pace. When going uphill, your glutes contract intensely and gradually become toned.
Your calves help extend the ankles and play a role in generating momentum.