Voluntary muscles

The key voluntary muscles used in sport are shown in the illustration.

Name of muscle	Function	Example in sport
Triceps	Extend the arm at the elbow	Press-up, throwing a javelin
Biceps	Flex the arm at the elbow	Pull-up, drawing a bow in archery
Deltoids	Move the arm in all directions at the shoulder	Bowling a cricket ball
Pectorals	Adduct the arm at the shoulder	Forehand drive in tennis
Trapezius	Hold the shoulders in place, move head back and sideways	Holding head up in rugby scrum
Gluteals	Adduct and extend leg at the hips	Pulling back leg before kicking a ball
Quadriceps	Extend the leg at the knee	Kicking a ball jumping upwards
Hamstrings	Flex the leg at the knee	Bending knee before kicking a ball
Gastrocnemius	Pointing the toes, help to flex the knee	Running
Latissimus dorsi	Adduct and extend the arm at the shoulder	Butterfly stroke in swimming
Abdominals	Flex the trunk across the stomach	Pulling the body down when hurdling

Drawing a bow uses the biceps. Photo courtesy of BBC Sport

Origin and insertion of muscles (AQA only) The origin is the end of a muscle which is attached to a fixed bone. The insertion is the end of the muscle that is attached to the bone which moves.