The structure and functions of the musculoskeletal system — AQA GCSE Physical Education

This criterion asks you to identify bones by their location on the body, so learn each bone name alongside where it sits and what it does. Build a mental map: cranium at the head, clavicle at the shoulder girdle, scapula at the upper back, humerus in the upper arm, radius and ulna in the forearm, carpals in the wrist, pelvis at the hips, femur in the thigh, patella at the knee, tibia and fibula in the lower leg, tarsals in the ankle and vertebrae in the spine. For each, note one function, such as the cranium protecting the brain or the femur bearing weight. In a multiple-choice question, read the location given, picture the skeleton, then eliminate options that name a bone from a different region.

The head and neck region is built from the cranium and the vertebrae. The cranium is the bony case that encloses and protects the brain; it also gives attachment to muscles of the face and jaw. The vertebrae are the individual bones of the vertebral column, stacked to form the spine, which supports the head, allows movement of the neck and trunk, and shields the spinal cord. In the neck the cervical vertebrae carry the skull, so a blow or sudden jolt can stress this region. For a multiple-choice question, link each named bone to its location and protective or supporting job, and reject options that swap the roles of cranium and vertebrae or place the cranium in the trunk.

The shoulder region is formed where the scapula and the humerus meet. The scapula is the flat, triangular shoulder blade at the back of the upper trunk; it gives a broad surface for muscle attachment and, with the clavicle, helps form the shoulder girdle. The humerus is the long bone of the upper arm. Its rounded head fits into the shallow socket of the scapula to make the shoulder joint, a ball-and-socket joint that allows a wide range of movement such as flexion, extension, abduction and rotation. In a multiple-choice question, link each bone to its shape, position and role, and reject options that place the scapula in the forearm or give the humerus the flat blade shape.

The chest, or thorax, is built around the rib cage. The ribs are curved bones that spring from the thoracic vertebrae at the back and sweep round to the front, where most of them join the sternum, the flat breastbone running down the midline of the chest. Together the ribs and sternum form a protective cage around the heart and lungs and give attachment points for muscles such as the intercostals. In movement terms the chest is not a freely moving joint like the elbow; it is a bony structure whose main jobs are protection and support. A question may ask you to identify the bones of the chest or to state the function of the rib cage, so link each named bone to its protective role rather than treating the chest as a joint.

The elbow is a hinge joint formed where the humerus, the single bone of the upper arm, meets the two bones of the forearm, the radius and the ulna. The humerus runs from the shoulder to the elbow; below the elbow the radius lies on the thumb side and the ulna on the little-finger side. At the elbow the humerus articulates with the forearm bones so the joint can bend and straighten, which is what allows actions such as a biceps curl or a throwing arm to flex and extend. A question may ask you to name the bones meeting at the elbow or to identify the joint type, so link each named bone to its position and to the hinge movement the joint produces.

The hip joint is a synovial ball-and-socket joint where the rounded head of the femur fits into a cup-shaped socket (the acetabulum) in the pelvis. This arrangement lets the femur move in three planes, so the leg can swing forward and back, move out to the side and rotate. The pelvis forms the stable socket and the femur is the long bone of the thigh that acts as the moving lever. Strong ligaments and the deep socket give the joint stability while still allowing a wide range of movement, which is why the hip carries body weight during standing, walking and running. In a multiple-choice question, match the joint to the two bones named in the statement: pelvis and femur, not tibia or patella.

The knee joint is a synovial hinge joint formed where the femur (thigh bone) meets the tibia (shin bone). A hinge joint mainly allows flexion and extension, so the lower leg bends and straightens beneath the thigh. The patella, or kneecap, is a small bone that sits in front of the knee joint; it protects the front of the joint and improves the leverage of the quadriceps muscle as the leg extends. The fibula runs alongside the tibia but is not the main bone forming the knee joint with the femur. In a multiple-choice question, select the option that names the femur and tibia as the joint bones and places the patella in front of the joint.

The ankle joint links the lower leg to the foot and is built from three named bones. The tibia is the larger, weight-bearing shin bone and forms the main part of the joint surface above the foot. The fibula is the thinner bone running down the outside of the lower leg and helps form the outer side of the ankle. The talus is the bone of the foot that sits between the tibia and fibula above and the heel bone below, so it transmits body weight and allows the foot to move up and down. Together these three bones create the hinge-type joint that lets a performer point the toes in a jump or drive off the ground in a sprint. Learn the three names and the position of each, because questions ask you to identify which bones make up the ankle rather than the whole leg or foot.

The skeleton is a rigid framework of bones that gives the body shape and support and provides places where muscles attach. Muscles attach to bones by tendons, and bones meet at joints. When a muscle contracts it pulls on a bone, and because bones are levers that pivot at joints, the pull produces movement. For example, the biceps contracts and pulls the radius, bending the elbow, while the triceps contracts to straighten it. So the skeleton alone cannot move the body: it supplies the framework, levers and attachment points, and the muscular system supplies the pulling force. Learn to explain this partnership, naming a joint, the bones and the muscles that work across it, because questions ask how the two systems combine to create movement rather than what either does alone.

The skeleton is not a rigid cage: it is a system of bones linked at joints, and those joints are the places where movement happens. A joint is where two or more bones meet, and the way the bones are shaped and held together decides how they can move. At a hinge joint such as the knee, the bones act like a door on hinges, so the lower leg swings in one plane. At a ball-and-socket joint such as the shoulder, the rounded head of one bone sits in a cup of another, so the arm can swing in many directions. Muscles pull on the bones across the joint to produce the movement, but the skeleton supplies the levers and the meeting points that make movement possible. In a multiple-choice question, choose the option that links bones meeting at a joint with movement, and reject options that say bones move on their own or that muscles alone create movement without the skeleton.

Bones differ in shape and type, and that difference affects how much and what kind of movement they allow. Short bones are roughly as long as they are wide, like the carpals of the wrist and the tarsals of the ankle. Because they are compact and packed closely together, they allow many small adjustments, so they support finer, more controlled movements such as the delicate movements of the fingers and wrist. Long bones are longer than they are wide, like the femur, humerus and tibia. They act as long levers, so a muscle pull produces a large sweep of movement, giving gross movements such as running, jumping and throwing. In a multiple-choice question, match the bone type to the quality of movement: short bones to fine control, long bones to large gross actions. Reject options that swap these roles or that say bone shape has no effect on movement.

Flat bones are broad, flattened or slightly curved bones whose main job here is protection: they form a hard shield around soft vital organs so that impact is spread over a wide area rather than concentrated on the organ. The cranium (skull) is a set of flat bones enclosing the brain, and the ribs are flat bones forming a cage around the heart and lungs; the sternum and the scapulae are also flat bones. A useful method is to name the bone, name the organ it shields and explain that the broad surface deflects or spreads force. Flat bones also give attachment for muscles and, in the sternum, produce blood cells, but the protection function is the one tested here.

A joint is where two or more bones meet, and its type sets the range of movement possible. A fixed (fibrous) joint such as a suture in the skull allows no movement. A cartilaginous joint such as between the vertebrae allows only slight movement. A synovial joint is freely movable, and its sub-type decides the movement: a hinge joint (elbow, knee) allows flexion and extension only, a ball-and-socket joint (shoulder, hip) allows flexion, extension, abduction, adduction, rotation and circumduction, a pivot joint (neck) allows rotation, a condyloid joint (wrist) allows flexion, extension, abduction and adduction, and a saddle joint (thumb) allows similar movement plus opposition. Match the joint to its structure, then to the movements it permits.

This function links the skeleton to movement. Bones give muscles a firm place to attach, usually through tendons that cross a joint, so a contracting muscle has something solid to pull against. When a muscle contracts it shortens and pulls the bone, and because the bone pivots at a joint the pull produces movement rather than a straight-line drag. Muscles can only pull, not push, so movement in the opposite direction needs an opposing muscle group working as an antagonist. A concrete example is the biceps contracting to pull the radius and ulna, bending the elbow, while the triceps relaxes. The key idea to hold on to is attachment plus contraction equals bone being pulled and a joint moving.

The skeleton performs several distinct jobs that questions often test together. It supports the body, holding it upright and giving it shape. It protects vital organs, for example the cranium guarding the brain and the ribcage guarding the heart and lungs. It provides points of attachment for muscles, so a contracting muscle pulls a bone and produces movement at a joint. It stores minerals such as calcium and phosphorus, and it produces blood cells in the bone marrow. A strong answer names each function and backs it with a quick example, such as the vertebrae supporting the trunk or the pelvis attaching the hip muscles. Keep the functions separate so each one is clearly credited.

The musculoskeletal system has several functions, and one of them is support. The skeleton forms a rigid internal framework of bones that holds the body upright and gives it shape, so soft tissues such as muscles, organs and skin are held in place rather than collapsing. For example, the vertebral column keeps the trunk upright, and the leg bones hold the body's weight above the ground. Support works together with the other functions of the skeleton, such as protection, movement, blood cell production and mineral storage, but in a question about support you should choose the option that describes holding the body up and giving it shape, not shielding organs or producing movement.

One function of the skeleton is protection of vital organs, and flat bones do this job. Flat bones are broad, flattened bones that form a shield around soft organs. The cranium, a flat bone of the skull, encloses the brain; the sternum and ribs form the rib cage that protects the heart and lungs; and the pelvis helps protect organs in the lower abdomen. In a multiple-choice question you should pick the option that names a flat bone shielding a named vital organ, and reject options that describe support, movement or mineral storage, because those are different functions of the skeleton.

Movement is one of the functions of the musculoskeletal system: bones act as levers, joints act as pivots and muscles provide the force that pulls on bones to produce motion at a joint. A muscle can only pull, so movement at a joint needs a pair of muscles working as an antagonistic pair: as the agonist contracts and shortens, the antagonist relaxes and lengthens to allow the joint to move. For example, at the elbow the biceps contracts to flex the joint while the triceps relaxes, and the triceps contracts to extend it while the biceps relaxes. The type and range of movement depend on the joint type, such as a hinge or ball-and-socket joint.

Bones have different structural shapes suited to their roles, and they provide points for attachment where muscles and ligaments join. Long bones such as the femur act as levers, short bones such as those in the wrist allow a range of movement, flat bones such as the cranium protect organs and give a broad surface for muscle attachment, and irregular bones such as the vertebrae have complex shapes for support and protection. Ridges, tuberosities and processes on a bone give grip and surface area for tendons to attach, so a contracting muscle can pull on the bone. Ligaments attach bone to bone at joints, while tendons attach muscle to bone.

Bones act as a living store of minerals that the body draws on to keep blood chemistry steady. The skeleton holds most of the body's calcium and phosphorus, mainly as calcium phosphate in the hard matrix of bone. When blood calcium falls, hormones such as parathyroid hormone signal bone cells to release calcium into the blood; when calcium is high, the hormone calcitonin encourages deposition into bone. This give-and-take keeps muscles and nerves working and supports clotting. In exam questions, mineral storage is one function of the skeleton alongside support, protection, movement, blood cell production and shape. A useful method is to link the function to a named mineral and to the process of release or deposition, rather than simply writing that bones 'hold minerals'.

Blood cell production is a function of the skeleton carried out in red bone marrow, the soft tissue found inside certain bones such as the pelvis, sternum, ribs, vertebrae and the ends of long bones. Red marrow contains stem cells that divide and develop into red blood cells, white blood cells and platelets. Red blood cells carry oxygen, white blood cells help defend against infection and platelets help blood to clot. In children, red marrow is present in more bones, while in adults it is concentrated in the flat bones and the ends of long bones, with yellow marrow storing fat in the shafts. A reliable method is to name the site (red bone marrow), the cells produced and one job of each cell type, keeping this function distinct from mineral storage.

This row is course guidance rather than an assessed answer target: it tells you how to study the functions of the musculoskeletal system. Learn each function (support, protection, movement, muscle attachment, joints allowing movement, production of blood cells and storage of minerals) and then practise applying it to a named physical activity. For example, take a netball landing and explain how the skeleton supports the body, how the bones protect organs, how muscles attached to bones pull to create movement at a joint, and how joints permit the required range of movement. Build a habit of pairing every function with a concrete sporting example, because the specification asks for application to performance, not recall alone.

This criterion asks you to identify named muscles and locate them within the body. Learn each muscle's position and a movement it produces so you can pick it out on a diagram or in a description. For example, the deltoid sits at the shoulder and abducts the arm; the pectorals lie across the chest; the biceps are at the front of the upper arm and flex the elbow; the triceps are at the back of the upper arm and extend the elbow; the abdominals are at the front of the trunk; the quadriceps are at the front of the thigh and extend the knee; the hamstrings are at the back of the thigh and flex the knee; the gastrocnemius forms the calf and plantarflexes the ankle; the gluteals are at the buttocks and extend the hip; and the latissimus dorsi lies across the back. In a multiple-choice question, match the described position or action to the correct muscle name.

The latissimus dorsi is a large, flat muscle of the back. It is one of the muscles learners must be able to name and locate within the muscular system, and it works with other muscles to move the shoulder joint. Its main actions are to extend, adduct and medially rotate the arm at the shoulder, so it contributes to pulling movements such as a pull-up or a swimming stroke. In multiple-choice questions you may be asked to identify its position, its action at the shoulder, or the movement it produces. Learn its location on the back and link it to a sporting action so you can recognise the correct option and reject distractors that describe other muscles.

The deltoid is the triangular muscle that covers the top of the shoulder. It is one of the major muscles learners must be able to name and locate, and it acts at the shoulder joint. Its main actions are to abduct the arm at the shoulder, and it also assists in flexion and extension of the arm at the shoulder. In multiple-choice questions you may be asked where the deltoid is found, which movement it produces, or which sporting action relies on it, such as raising the arm in a tennis serve or a swimming stroke. Learn its position over the shoulder and its main action of abduction so you can select the correct option and reject distractors describing other muscles.

The rotator cuff is a group of four muscles and their tendons that wrap around the shoulder joint: supraspinatus, infraspinatus, teres minor and subscapularis. They hold the head of the humerus in the shallow glenoid cavity of the scapula while the arm moves, so they stabilise the shoulder rather than produce large powerful movements. Each muscle rotates the humerus in a different direction, which is why the group is named for rotation. In a multiple-choice question you may be asked to identify the joint they stabilise, the bones involved, or the function they perform. Link the answer to stabilisation of the shoulder joint during movement, and rule out options describing the knee, hip or elbow.

The pectorals are the chest muscles, chiefly pectoralis major, which lie across the front of the rib cage and attach the humerus to the sternum, clavicle and ribs. When they contract they adduct the arm, bringing it across the body, and flex the shoulder, raising the arm forwards. They also assist movements such as pushing, throwing and the press-up. In a multiple-choice question you may be asked to name the movement produced at the shoulder, the bones the muscle connects, or an activity that uses the pectorals. Link the answer to the front of the chest and to pulling the arm forwards and across the body, and rule out options describing the back, legs or lower arm.

The biceps is a skeletal muscle at the front of the upper arm that acts as a flexor at the elbow joint. When the biceps contracts it shortens, pulling on the radius through the biceps tendon and bending the elbow, as when lifting a bag or performing a biceps curl. During this action the biceps is the agonist (prime mover) and the triceps, at the back of the arm, is the antagonist that relaxes and lengthens. The muscle works across the elbow joint in a lever system, with the elbow as the pivot. Learners should be able to identify the biceps by name and position, state its role in flexion and distinguish it from the triceps in a multiple-choice question.

The triceps is a skeletal muscle at the back of the upper arm that acts as an extensor at the elbow joint. When the triceps contracts it shortens, pulling on the ulna through the triceps tendon and straightening the elbow, as when pushing up from the floor or performing a triceps dip. During this action the triceps is the agonist (prime mover) and the biceps, at the front of the arm, is the antagonist that relaxes and lengthens. The muscle works across the elbow joint in a lever system, with the elbow as the pivot. Learners should be able to identify the triceps by name and position, state its role in extension and distinguish it from the biceps in a multiple-choice question.

The abdominals are a group of muscles in the front of the trunk, sitting below the chest and above the pelvis. In movement they flex the trunk forward, as when a performer curls up during a sit-up, and they help to stabilise the core so the trunk stays controlled while the limbs work. They also support the internal organs and assist forced expiration of air. A question on this statement may ask you to identify the abdominals from a description of their action, to name the movement they produce at the trunk, or to pick them out as the muscles responsible for a given sporting action such as a crunch or a pike position in diving. Link the muscle to the joint it crosses and to the movement it creates, rather than learning the name alone.

The hip flexors are the muscles that bend the leg forward at the hip joint, lifting the thigh towards the trunk. A key member is the iliopsoas, working with the rectus femoris, and together they produce hip flexion. In sport this action appears when a sprinter drives the knee up, when a footballer lifts the leg to strike a ball, and when a gymnast raises the legs in a pike. A question may ask you to name the movement the hip flexors create, to identify them from a description of knee lift, or to select them as the muscles working in a given action. Remember that flexion at the hip is the opposite of extension, which the gluteals produce.

The gluteals are the muscles of the buttocks, sitting at the back of the pelvis. Their main job in movement is hip extension: they pull the femur backwards so the leg drives behind the body, as in the drive phase of sprinting or the push-off in a jump. The largest of them, gluteus maximus, is the powerful extensor; the smaller gluteus medius abducts the leg away from the midline and helps stabilise the pelvis when you stand on one leg. In an MCQ you may be asked to name the muscle group responsible for hip extension, to locate it, or to pick it out from a list of muscles that flex the hip, such as the iliopsoas. Link the gluteals to the movement they produce rather than to a single sporting example, and remember they work as a group at the hip joint.

The hamstring group is the set of muscles at the back of the thigh. The specification names the group as a whole, so learn it as 'the hamstrings' rather than as separate muscles. Its main action is knee flexion, bending the lower leg backwards, and it also helps extend the hip. You use the hamstrings when you bend the knee to bring the heel towards the buttocks in running, and they act as the antagonist to the quadriceps at the knee: as the quadriceps contract to straighten the knee, the hamstrings relax and lengthen. In an MCQ you may be asked which muscle group flexes the knee, where the hamstrings sit, or which group opposes the quadriceps. Answer with the group name and link it to knee flexion at the knee joint.

The quadriceps are a group of muscles at the front of the thigh that work together to straighten the knee (knee extension). AQA names the group as a whole, so a correct answer identifies the quadriceps rather than listing the individual muscles inside it. Link the group to its joint action: when the knee extends, for example in the upward drive of a jump or the kicking phase of a sprint, the quadriceps are the agonist (prime mover) and the hamstrings at the back of the thigh act as the antagonist. In a multiple-choice question, read each option and decide whether it names the group, a different muscle group, or an individual muscle; only the group name matches the specification wording.

The gastrocnemius is a muscle in the calf at the back of the lower leg. It works with the soleus to point the foot downwards, a movement called plantar flexion at the ankle. This action provides the push-off in running, jumping and walking. When the ankle plantar flexes, the gastrocnemius is the agonist (prime mover) and the tibialis anterior at the front of the shin is the antagonist. In a multiple-choice question, match the option to the correct location (back of the lower leg) and the correct action (plantar flexion), and reject options that place it elsewhere or give the opposite movement.

The tibialis anterior is a muscle at the front of the lower leg, running down the shin beside the tibia and attaching towards the foot. It works as an antagonist to the calf muscles: when it contracts it pulls the foot upwards towards the shin, a movement called dorsiflexion, and it controls the foot as it lowers during walking and running. Learners should place it on the front of the shin, distinguish it from the gastrocnemius and soleus at the back of the lower leg, and link its contraction to dorsiflexion rather than plantar flexion. A useful check is to picture lifting the toes and the front of the foot while the heel stays down, which is the action the tibialis anterior produces.

Tendons are tough, slightly elastic cords of connective tissue that join muscle to bone. When a muscle contracts it shortens, and the tendon carries that pull to the bone so the bone moves at a joint; for example, the Achilles tendon attaches the calf muscles to the heel bone and helps raise the heel during running and jumping. Learners should separate tendons from ligaments, which join bone to bone and stabilise joints, and from cartilage, which cushions bone ends. A reliable check is to ask what each structure connects: muscle to bone means tendon, bone to bone means ligament. Tendons also help transmit force efficiently and store and return some energy in activities such as jumping.

A synovial joint is where two or more bones meet, are separated by a fluid-filled cavity and allow movement, as at the knee, hip, shoulder and elbow. You must be able to identify its structures and explain how each helps to prevent injury. The articular cartilage caps the bone ends and reduces friction and wear. The synovial membrane lines the joint capsule and secretes synovial fluid, which lubricates the joint and absorbs shock. The joint capsule is a tough fibrous sleeve that holds the bones together and limits unwanted movement. Ligaments join bone to bone and stabilise the joint, while tendons attach muscle to bone and control movement. Recognise each structure on a diagram and link it to the injury it helps to prevent.

The synovial membrane is a thin layer of tissue that lines the inside of the joint capsule of a synovial joint, such as the knee or shoulder. It does not cover the bone ends; the articular cartilage does that. The membrane secretes synovial fluid into the joint cavity. This fluid lubricates the moving surfaces so they glide smoothly, reduces friction and wear, and absorbs some shock when the joint is loaded. By keeping friction low and cushioning impact, the synovial membrane and its fluid help to prevent injury to the joint structures. When identifying it on a diagram, look for the lining of the capsule around the cavity, not the smooth cap on the bone ends.

Synovial fluid is the slippery liquid found inside the cavity of a freely movable (synovial) joint, such as the knee or shoulder. It is produced within the joint and fills the space between the articulating surfaces of the bones. Its main jobs are to lubricate those surfaces so they glide over each other with less friction, to nourish the cartilage that covers the bone ends, and to absorb some of the shock and impact passing through the joint during movement. Because it reduces friction, synovial fluid helps protect cartilage from wear and allows smooth, efficient movement at the joint. In a multiple-choice question you may be asked what synovial fluid does or where it is found; link it firmly to friction reduction, lubrication, cartilage nutrition and shock absorption inside a synovial joint.

The joint capsule is the tough, fibrous sleeve of connective tissue that surrounds a freely movable (synovial) joint, such as the knee, shoulder or hip. It encloses the joint cavity and holds the articulating bones together, giving the joint stability while still allowing movement. The capsule has an outer fibrous layer, which is strong and helps prevent dislocation, and an inner lining (the synovial membrane) that produces synovial fluid to lubricate the joint. Ligaments may thicken parts of the capsule to add further strength. In a multiple-choice question you may be asked what the joint capsule is or what it does; link it firmly to enclosing the joint, holding bones together, providing stability and containing synovial fluid.

Bursae are small fluid-filled sacs found where tendons or muscles pass over bone, for example at the shoulder, knee and elbow. Each sac contains synovial fluid and acts as a cushion, reducing friction and allowing smooth movement at a joint. In this multiple-choice question you must recognise bursae as a named structure of the musculoskeletal system and match them to their function of reducing friction between moving parts. Read all options before choosing, then check that your chosen answer describes a cushioning sac rather than bone, muscle or connective tissue.

Cartilage is a smooth, tough connective tissue that covers the ends of bones at a joint. It cushions the bone ends, reduces friction between them and helps absorb shock during movement, for example at the knee or hip. In this multiple-choice question you must recognise cartilage as a named structure of the musculoskeletal system and match it to its protective, friction-reducing role at joints. Read each option carefully and reject any that describe bone, muscle, ligament or a fluid-filled sac, then choose the option that correctly describes cartilage covering bone ends.

Ligaments are tough bands of fibrous connective tissue that join one bone to another bone across a joint. Their main function is to hold the bones of a joint together and to limit how far the joint can move, which keeps the joint stable and reduces the risk of dislocation. They are not the same as tendons, which attach muscle to bone and transmit the pull that produces movement. A useful way to remember the difference is to link the letter 'L' in ligament to 'links bones'. In a knee, the ligaments on either side of the joint resist unwanted sideways movement while still allowing the controlled bending and straightening needed for running and kicking. Ligaments have some elasticity but are far less stretchy than muscle, so they stabilise rather than generate force.

Freely movable joints, also called synovial joints, allow a wide range of movement and are the joints most involved in sport and physical activity. The specification asks you to identify types of freely movable joint. A hinge joint, such as the elbow or knee, allows bending (flexion) and straightening (extension) in one plane. A ball-and-socket joint, such as the shoulder or hip, allows movement in several directions, including flexion, extension, abduction, adduction and rotation. A pivot joint, such as between the atlas and axis in the neck, allows rotation. A condyloid joint, such as the wrist, allows bending and straightening plus side-to-side movement. To identify a joint type, look at the shape of the bone ends and the number of directions in which movement is possible.

A hinge joint is a synovial joint that allows movement in one plane only, like the opening and closing of a door. The elbow, knee and ankle are the three hinge joints named in this specification. At each, one bone with a convex surface fits against a concave surface of another, and strong ligaments on either side restrict sideways movement. The elbow lets the forearm flex and extend relative to the upper arm; the knee lets the lower leg flex and extend relative to the thigh; the ankle lets the foot dorsiflex and plantar flex relative to the lower leg. A multiple-choice question may ask you to identify which of these joints is a hinge joint, or to pick the movement a hinge joint permits. Read each option carefully and reject any joint that allows rotation or movement in several planes, because those belong to ball and socket joints.

A ball and socket joint is a synovial joint in which the rounded head of one bone fits into a cup-shaped cavity of another. The hip and shoulder are the two ball and socket joints named in this specification. The shoulder joint joins the humerus to the scapula, and the hip joint joins the femur to the pelvis. Because the ball can roll and turn inside the socket, these joints allow movement in several planes, including flexion, extension, abduction, adduction, rotation and circumduction. A multiple-choice question may ask you to identify which joints are ball and socket joints, or which movements they permit. Compare each option with the one-plane limit of a hinge joint and reject any option that describes movement in a single plane only.

Joints are built differently because their structure decides which movements they permit. A hinge joint, such as the elbow or knee, has bones shaped to meet like a door hinge, so it allows flexion and extension but not rotation. A ball-and-socket joint, such as the shoulder or hip, has a rounded head sitting in a cup-shaped socket, so it allows flexion, extension, abduction, adduction, rotation and circumduction. A pivot joint, such as the joint between the atlas and axis in the neck, allows rotation only. A condyloid joint, such as the wrist, allows flexion, extension, abduction and adduction. The design of the joint surfaces, ligaments and capsule therefore links directly to the movement available, and a question may ask you to match a named joint to its type or to the movement it enables.

Flexion and extension are opposite movements at the same joint. Flexion decreases the angle at a joint, for example when you bend your elbow to bring your hand towards your shoulder or lift your knee towards your chest at the hip. Extension increases the angle at a joint, returning it towards straight, for example when you straighten your elbow or swing your leg backwards at the hip. At the shoulder, flexion raises the arm forwards and upwards, while extension moves the arm backwards. At the elbow and knee, which are hinge joints, flexion and extension are the main movements available. At the hip, a ball-and-socket joint, flexion and extension occur alongside other movements. A question may ask you to identify which movement is happening at a named joint during a described action, so link the direction of movement to the change in joint angle.

Abduction and adduction are antagonistic movements at the shoulder joint, which is a ball-and-socket joint allowing movement in several planes. Abduction moves the arm away from the midline of the body, for example lifting the arm out sideways until it is level with the shoulder. Adduction moves the arm back towards the midline, for example bringing a raised arm down to the side of the trunk. The pair is defined by direction relative to the body's midline, not by whether the arm is in front of or behind the body. A useful check is to picture the midline running vertically through the centre of the trunk: movement away from it is abduction, movement towards it is adduction. The muscles producing these movements act as an antagonistic pair, with one contracting while the other relaxes and lengthens under control.

Rotation at the shoulder is a turning movement of the humerus around its own long axis while the joint stays in place. The ball-and-socket structure of the shoulder allows this circular turning, so the arm can rotate inwards (medial rotation) or outwards (lateral rotation). An example of medial rotation is turning the upper arm so the forearm swings across the front of the body; lateral rotation turns the upper arm so the forearm swings away from the body. Rotation differs from circumduction, which sweeps the arm through a cone-shaped path, and from abduction, which lifts the arm away from the midline. To identify rotation, check whether the bone turns about its own axis rather than travelling through space. Muscles around the shoulder contract and relax as an antagonistic pair to control the turning in each direction.

Circumduction is a movement at a ball-and-socket joint in which the distal end of the limb traces a circle while the proximal end stays still. At the shoulder, the humeral head remains in the glenoid cavity of the scapula and the hand or elbow sweeps a cone-shaped path. Picture a swimmer doing a full arm circle in front crawl, or a bowler's arm rotating through a wide loop: the arm moves forward, out to the side, backward and back to the start in one continuous sequence. Circumduction combines flexion, extension, abduction and adduction in order, so it is not the same as rotation, where the bone turns about its own long axis without the end travelling round a circle. The shoulder joint's capsule, ligaments and surrounding muscles such as the deltoid and rotator cuff guide and stabilise this wide range.

At the ankle, movement happens in two directions. Dorsiflexion brings the top of the foot towards the shin, so the foot angle narrows; think of lifting the toes as the heel strikes the ground. Plantar flexion points the foot away from the shin, so the heel rises and the toes push down; think of the drive phase of a sprint or rising onto the balls of the feet. Both movements occur at the ankle joint, where the tibia, fibula and talus meet, and both depend on muscles crossing that joint: the tibialis anterior produces dorsiflexion, while gastrocnemius and soleus produce plantar flexion. In a multiple-choice question, identify which bone is moving, in which direction, and which muscle group is working. Keep the ankle as the joint in question, and treat the ball of the foot as the contact point rather than the joint itself.

This row is a signpost, not a body of content to memorise. It tells you that the musculoskeletal section (3.1.1.1) covers structure and function — bones, joints, muscles and how they work together — while the application of those ideas to named sporting actions belongs to the movement analysis section on page 16. Read the musculoskeletal material for the anatomy itself: the functions of the skeleton, the types of joint and the muscles acting at them. Then, when you reach movement analysis, carry that anatomy forward and apply it to specific actions such as a basketball jump shot or a sprint start. Keep the two sections linked in your notes rather than treating them as separate subjects, and check the specification page reference so you revise the right content in the right place.

Antagonistic pairs are two muscles that produce opposite movements at a joint. As one muscle (the agonist or prime mover) contracts and shortens, the other (the antagonist) relaxes and lengthens to allow the movement. At the shoulder, the deltoid and latissimus dorsi work as an antagonistic pair; at the elbow, the biceps and triceps; at the hip, the hip flexors and gluteals; at the knee, the quadriceps and hamstrings; at the ankle, the tibialis anterior and gastrocnemius. For each joint you should be able to name the pair, state which muscle contracts to produce a given movement such as flexion or extension, and identify which relaxes. Apply this to physical activity, for example the biceps contracting to flex the elbow in a biceps curl while the triceps relaxes.

This criterion asks you to name the major muscle groups that move the body at the joints already covered in the specification, such as the shoulder, elbow, hip and knee. Learn each muscle with the joint it crosses and the movement it produces. At the elbow, the biceps brachii in the front of the upper arm flexes the joint, while the triceps brachii at the back extends it. At the shoulder, the deltoid abducts the arm and the pectorals and latissimus dorsi move it across the body. At the hip, the gluteals extend and the hip flexors flex, and at the knee the quadriceps extend while the hamstrings flex. At the ankle the gastrocnemius plantar-flexes and the tibialis anterior dorsiflexes. Link each muscle to its joint, its movement and a sporting example so the pairing is secure.

This criterion asks you to explain how a prime mover, also called the agonist, and its antagonist work together to produce movement at a joint. The prime mover contracts to create the movement, while the antagonist relaxes and lengthens to allow it. During elbow flexion the biceps brachii is the prime mover and the triceps brachii is the antagonist; during elbow extension the roles reverse, so the triceps contracts as prime mover and the biceps relaxes as antagonist. The pair works as an antagonistic pair because muscles can only pull, not push, so a joint needs opposing muscles to move in both directions. Apply this to a sporting example, such as the biceps acting as prime mover in a biceps curl and the triceps acting as prime mover when the arm straightens.

This criterion asks you to identify the specific bones that meet at a named joint, so you can describe the joint's structure accurately. At the knee, the femur (thigh bone) meets the tibia (shin bone), with the patella (kneecap) sitting in front of the joint. At the elbow, the humerus (upper arm bone) meets the radius and ulna (forearm bones). At the hip, the femur fits into the pelvis. At the shoulder, the humerus meets the scapula. Learn each joint as a set of named bones rather than a vague 'arm bone' or 'leg bone', because a multiple-choice question will test whether you can match the correct bone names to the correct joint.

This criterion asks you to explain how muscle groups produce movement in three ways. In an isometric contraction the muscle stays the same length and the joint angle does not change, as when you hold a plank or push against a wall. In an isotonic contraction the muscle changes length and the joint moves. A concentric contraction shortens the muscle while it produces force, as the biceps do when you lift a dumbbell in a curl. An eccentric contraction lengthens the muscle while it still produces force, as the biceps do when you lower the dumbbell slowly. A multiple-choice question may give a sporting action and ask which type of contraction is happening, so link each definition to a clear example.

Isotonic contractions change muscle length while tension stays roughly constant, and they come in two directions. In a concentric contraction the muscle shortens as it develops tension, so it pulls on the bone and creates movement; the biceps brachii shortening to lift a dumbbell in a biceps curl is the standard example. In an eccentric contraction the same muscle lengthens under tension while still resisting the load, controlling the movement rather than driving it; lowering that dumbbell slowly back down is eccentric work by the biceps. The key difference is therefore the direction of length change: shortening in concentric, lengthening under tension in eccentric. Both are isotonic because the muscle changes length and moves a joint, which separates them from isometric contraction where length stays the same. Recognise the action in a sporting example and match it to the correct term.