Isometric
A form of physical exercise in which muscles are contracted, but not allowed to move the associated joints. Muscles are used in this way when exerting force on a closed door or fixed bar. Isometric exercises are often undertaken to strengthen muscles not much used in everyday movements.
Iso means same and metric means length. Force of muscle contraction= force expressed by resistance.
Advantages of isometric training large amount of strength training can be done in a short time, another advantage is that there is no special place or equipment needed and can be done any time throughout the day.
Isotonic and isokinetic muscle contraction
The sort of exercise in which muscles are used in a normal dynamic way and in which muscles contract at a speed controlled by a shot-putter is called isotonic.
In this case, the work is Labelled concentric or positive because the resulting tension causes the muscle to create movement by shortening its length.
The advantage of this type of exercise is that it stimulates real sporting use of the musculature.
One of the adaptions produced by this type of training or exercise is to increase the capillarisation of both skeletal and cardiac muscle and to enable these muscles to become more resistant to the onset of fatigue. This means that there is more likely to lead to improvement in sporting performance.
In isokinetic exercise, the point at which force acts moves at constant speed. For example, in a squat the shoulders move upward at a constant speed regardless of effort put into the exercise.
The advantages of isokinetic training is that it removes from the exercise the differences between forces exerted at different angles of limbs at a joint.
Synovial Joints
Synovial joints are specialized to allow generally free movement, and constitute the majority of permanent joints in the limbs. Several types can be identified according to the shape of their articulating surfaces, which in turn determines the type of movement possible at the joint: plane joints (e.g. between the carpel bones), saddle joints (e.g. the carpo-metacarpal joint of the thumb), hinge joints (e.g. the elbow joint), pivot joints (e.g. the superior radio-ulnar joint), and ball-and-socket joints (e.g. the hip joint).
Joints are lubricated by "Synovial" fluid. Connections called "Synovial" joints are sturdy enough to hold the skeleton together and at the same time permit a range of motions. The ends of these joints are coated with cartilages, which reduce friction and cushion against jolts.
Cartilage:
- Consists of cell chondrocytes
- The chondrocytes are found in the matrix of the cell fibrils
- Chondrocytes produce the matrix
- Hard but flexible
- Found between joint’s/bones
- Elastic so that it’s flexible to with stand compressive forces (absorb shock).
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3 types; Hyaline, found at the end of bones, nose, air passages, and ear. Yellow elastic, not usually part of the actual skeleton. Highly elastic and returns to its original shape quickly e.g. Ligaments. White fibrous, cartilage contains bundles of collagen fibres not as flexible. Found between vertebrates.
Ligament:
- The amount of collagen, found within the ligament varies
- It allows the bones of the joints to move
- Yellow elastic cartilage
- Very flexible/elastic
- They form a capsule around the joints and hold the bones together
- Depends/ varies according to the joint – loose/tights, sometimes white fibrous cartilage is also found
