re exercising not only your triceps, biceps
and deltoids but also your abdominals, gluteals, ribcage intercostals,
chest pectorals
and hip stabilizers. In freestyle and backstroke, you use a flutter kick, engaging predominantly your quadriceps in the freestyle, hamstrings in the backstroke, and to a lesser degree, your calf and foot muscles.
Breaststroke and butterfly require lifting your head out of the water to breath, an action that depends largely on arm and leg power, not neck-strength.