Joint and movement type

Movements of synovial joints

Muscle contraction types• Concentric contraction – force is greater than resistance: muscle contracts and

becomes shorter• Isometric contraction – force and resistance is equal: muscle stays same

length• Eccentric contraction – force is less than resistance: muscle contracts but

lengthens• Isotonic contraction – force remains constant during movement (concentric or

eccentric contraction)• Isokinetic motion – constant speed of body segment around joint during

muscle contraction• Muscle relaxation – contractile units in muscle are not connecting (myosin

heads), contraction force is zero

Axes of rotation and planes of movement of the human body.

System of naming the movements of the body’s segments greatly assists the description and analysis of motion among sport scientists, PE teachers, coaches and sport medicine practitioners

There are three fundamental axes of rotation- The Anteroposterior axis (going front to back)- The Transverse axis (going from side to side)- The Vertical (longitudinal) axis (going from top to

bottom)

For the rotation of the body these axes pass through the center of massFor the rotation around the joints the axes pass through the joint’s center

Synovial joints have axes of rotation around which rotation to movement is permitted.• Non-axial - gliding joints

(carpals), no axis of rotation• Uniaxial - hinge joints

(elbow) and pivot joints, only one axis of rotation

• Biaxial - condylar (knee) and saddle joints, two axes, joints can move two different ways

• Traxial – ball and socket joints (shoulder), three axes, permit the greatest movement

Axes and planes

Movement patterns and body planes

Movements of synovial joints

Sports, exercise and health science. Page 83-84

Movements of the body segments at the joints are given particular names. The reference axis and planes are defined below. The movements are assumed to start with the body in the anatomical position. With the individual; standing upright, facing straight ahead with feet parallel and palms facing forward.

Agonistic muscle actionMuscles never work alone. In order for a coordinated movement to be produced, the muscles must work together in a group or team, with several muscles working at any one time.• The muscle that produces the desired movement is called the agonist or

prime mover, this produces the most force. The muscle that produces the opposite movement in order for the agonist to lengthen again is called the antagonist. For example the biceps brachii produces flexion in the elbow and the triceps produce extension in the elbow.

• Fixators or stabilizers are muscles that stabilize the origin of the agonist (joint) and prevent the movement of the bone, so that the agonist can achieve maximum and effective contraction

• Synergist or neutralizers are muscles that, in the same movement, modifies the direction of the movement and prevents any undesired movements which may occur.

Reciprocal inhibition When an agonist contracts to move a body segment it is usual for the antagonist (the muscle with the opposite concentric contraction action) to relax. This means it is not being opposed by any muscle torque acting in the opposite direction). Occasionally however, it is necessary for both to contract to provide joint stability (this is known as co-action).

Antagonistic pairingsPectoralis / TrapeziusRectus Abdominis / Erector SpinaeAnterior deltoids / Posterior deltoidsLatissimus dorsi / DeltoidsQuadriceps / Hamstring groupTibialis anterior / Gastronemius and SoleusBiceps brachii / Triceps brachiiWrist flexors / Wrist extensors

DOMS, delayed onset of muscle sorenessMuscle soreness occurring at least one day after exercise, possibly caused by structural damage within muscle membranes. Delayed onset muscle soreness is a normal response to unusual exertion and is part of an adaptation process that leads to greater stamina and strength as the muscles recover and build (hypertrophy).

Delayed onset muscle soreness is thought to be a result of microscopic tearing of the muscle fibers. The amount of tearing (and soreness) depends on how hard and how long you exercise and what type of exercise you do. Any movement you aren't used to can lead to DOMS, but eccentric muscle contractions (movements that cause muscle to forcefully contract while it lengthens) seem to cause the most soreness.

How can you prevent DOMS?- Reducing the eccentric muscle action during early training

- Starting training at low intensity and gradually increasing intensity

- Warming up before exercise

- Cooling down after exercise