Muscular system

• why does the skeleton need muscles

  to move the body (musculo-skeletal system)
• biceps

  flexion at the elbow e.g. curling weights
• triceps

  extension at the elbow e.g. jump shot in basketball
• pectorals

  adduction and flexion at the shoulder e.g. tennis forehand
• hip flexors

  flexion of the leg at the hip e.g. lifting the knee when sprinting
• gluteals

  extension, rotation and abduction of the leg at the hip e.g. pushing the body forward when running
• deltoid

  flexion, rotation, abduction or circumduction at the shoulder e.g. front crawl in swimming
• latissimus dorsi

  extension, adduction or rotation at the shoulder e.g. butterfly in swimming
• tibialis anterior

  dorsiflexion at the ankle e.g. snowboarding heel side turn
• rotator cuffs

  rotation and abduction at the shoulder e.g. lifting the arms when preparing to dive and stabilise shoulder joints during other movements
• abdominals

  flexion at the waist e.g. a sit-up
• gastrocnemius

  plantar flexion at the ankle e.g. ballet pointe work
• quadriceps group

  extension at the knee e.g. rugby drop kick
• hamstring group

  flexion at the knee e.g. preparing to kick a football
• sternocleidomastoid, trapezius and intercostal muscles

  moves the ribs when breathing
• muscles at the shoulder

  deltoid, rotator cuffs, trapezius, pectorals, latissimus dorsi, biceps, triceps
• muscles at the elbow

  biceps, triceps
• muscles at the hip

  hip flexors, gluteals
• muscles at the knee

  hamstring group, quadriceps group
• muscles at the ankle

  gastrocnemius, tibialis anterior
• isometric contractions

  the muscles stay the same length: there is no movement e.g. tug of war
• isotonic contractions

  the muscles change length: there is movement e.g. a press-up
• concentric contractions

  when the muscles contracts and shortens e.g. during the upward phase of a bicep curl, your biceps undergo a concentric contraction to pull your forearm and lift the weight
• eccentric contractions

  when a muscle contracts and lengthens which helps you control the speed of a movement e.g. during the downward phase of a bicep curl, your biceps contract eccentrically, creating tension so that the weight falls slowly
• Muscular system:

  A) sternocleidomastoid

  B) pectorals

  C) biceps

  D) abdominals

  E) quadriceps

  F) tibialis anterior

  G) intercostals

  H) rotator cuffs

  I) deltoid

  J) triceps

  K) latissimus dorsi

  L) hamstrings

  M) gastrocnemius