Muscles, Tendons and Ligaments
Muscles
There are about four hundred individual muscles in the body, making up roughly 45 per cent of total body mass, but only seventy-five pairs of these muscles are responsible for maintaining posture and producing the movements of arms and legs required for climbing.
There are three different sorts of muscles, made up of distinct fibre types:
Cardiac muscle
Smooth muscle
The above two are responsible for jobs which require continuous and independent action, as found in heart and walls of intestines.
Skeletal muscle (also called voluntary muscle)
You have active control over this muscle. How to manipulate it to improve strength, power and endurance that we are largely concerned.
Skeletal muscle composed of thousands of minute fibres, which are bound together by connective tissue to form fasciculi, which in turn are bound together to form the muscle itself.
There are three different types of Skeletal muscle fibres:
Slow twitch (known as red or type 1) fibres: responsible for aerobic endurance, and are capable of sustained work output.
Fast twitch (known as pale or type 2B) fibres: depend upon the stored energy sources within the muscle fibres. They are capable of high energy outputs, but only for short periods, as fatigue occurs as the energy the energy store runs out.
Fast twitch oxidation (known as type 2A) fibres: can work in either way.
It is said that the proportions of these fibre types within an individual's muscles may be genetically determined, and this is the reason why one person excels as a marathon runner and another as a sprinter. At the present time, however, the evidence is equivocal as to whether it is genetics or training that is the most important influence.
Oxygen is a key component in muscle contraction, although muscles can work for short periods without it. The length of time when muscles are working aerobically is dependent on (all these factors can be influenced by training):
Energy reserves
The efficiency of the muscle enzyme systems in utilizing the fuels of fatty acids and glucose.
The efficiency of the heart and lungs in delivering oxygen.
Muscles produce their force by contraction and can act in one of three ways:
Concentric contraction - occurs when the muscle shortens while producing a force (e.g. when pulling the body up). It is usually this action you are working on when trying to develop explosive power.
Eccentric contraction - occurs when the muscle lengthens while still producing a force (e.g. when letting the body down). It is this contraction that is mainly responsible for producing muscle soreness and is the most important muscle action that you need to control in order to prevent injury.
Isometric contraction - occurs when the muscle does not move and the muscle involved remains the same length (e.g. the work done when locked off on a hold). It can be used as a method of exercise in the early stages when recovering from injury and is useful at the beginning of a warm up.
Muscles exert their force through their tendons. These are the tough fibrous cords, made up from collagen, that run from fleshy substance of muscle belly and insert into the particular bone they are going to move. They are most easily seen on the back of the hand where they stand out under the skin. Each individual muscle and its tendon form a "muscle-tendon unit".
Collagen is a relatively inelastic material made up of chains of proteins that varies little in its composition wherever it is found in the body. It is the principal material that makes up tendons and ligaments. It has a crimped structure that enables it to lengthen by about 10 per cent when subjected to load, but after this, if the force is too great, it tears.
Tendons are structurally very strong, but not indestructible. They have a much poorer blood supply than muscle and therefore have lower metabolic rate. This means that they are capable of adaptation during training, but that this occurs at a much slower rate than in muscle. The poorer blood supply also means that they heal slowly after injury and are prone to develop overuse problems.
Ligaments are structurally very similar to tendons, also being made up largely of collagen. All joints are surrounded by fibrous capsule and the body uses ligaments as specialized static structures to provide extra stability. For example, there are small ligaments on either side of the finger joints to prevent sideways movement.
Ligaments are used by the body to both prevent abnormal movements and guide the normal movements of the joints, and their integrity may be critical for normal function. Unfortunately, ligaments suffer from the same poor blood supply as the tendons and therefore are prone to the same healing problems.
