Types of Muscle and Muscle Contraction

This section looks at the muscular system and the types of muscle contraction. 

The muscular system is a vital component of the human body responsible for movement, stability, and posture. It comprises various muscles, each with specific functions and roles. Understanding these muscles is crucial for athletes, as they play a significant role in sports performance.

Abdominals:

Function: The abdominals, including the rectus abdominis and obliques, stabilise the core, support the spine, and facilitate trunk flexion and rotation.

Example: Used in sports like gymnastics for tumbling sequences, in swimming for stability and streamlined posture, and in basketball for explosive movements such as jumps and pivots.

Biceps:

Function: The biceps brachii flex the elbow joint and supinate the forearm.

Example: Crucial in sports like weightlifting for bicep curls, in climbing for pulling movements, and in cricket for swinging a bat.

Deltoid:

Function: The deltoid muscle is responsible for shoulder abduction, flexion, and rotation.

Example: Essential for overhead movements in sports such as volleyball for spiking, in swimming for the freestyle stroke, and in basketball for shooting.

Gastrocnemius:

Function: The gastrocnemius is the main muscle of the calf, responsible for plantar flexion of the foot and ankle joint.

Example: Utilised in sports like sprinting for push-off, in volleyball for jumping, and in football for acceleration and quick changes of direction.

Hamstrings:

Function: The hamstrings consist of several muscles at the back of the thigh, responsible for knee flexion and hip extension.

Example: Crucial for running and sprinting in sports like football, in cycling for pedalling motion, and in gymnastics for jumps and flips.

Intercostals:

Function: The intercostal muscles are located between the ribs and assist in breathing by expanding and contracting the ribcage.

Example: Engaged in endurance sports like long-distance running and swimming, aiding in efficient breathing patterns.

Latissimus Dorsi:

Function: The latissimus dorsi, or lats, are large muscles of the back responsible for shoulder extension, adduction, and internal rotation.

Example: Used in sports like rowing for pulling the oar, in rock climbing for upward pulling movements, and in swimming for the butterfly stroke.

Pectorals:

Function: The pectoral muscles, or pecs, are located in the chest and are responsible for shoulder flexion, adduction, and internal rotation.

Example: Essential in sports like bench pressing in weightlifting, in swimming for the breaststroke, and in boxing for punching movements.

Quadriceps:

Function: The quadriceps are a group of four muscles at the front of the thigh, responsible for knee extension.

Example: Vital for movements such as jumping, squatting, and kicking in sports like football, basketball, and martial arts.

Rotator Cuffs:

Function: The rotator cuff muscles stabilise and support the shoulder joint, facilitating various shoulder movements.

Example: Essential for overhead throwing motions in sports like baseball and cricket, in tennis for serving, and in swimming for the backstroke.

Sternocleidomastoid:

Function: The sternocleidomastoid muscle is located in the neck and aids in neck flexion, rotation, and lateral flexion.

Example: Engaged in sports like wrestling for maintaining head position, in martial arts for executing punches and strikes, and in gymnastics for head movements during routines.

Tibialis Anterior:

Function: The tibialis anterior is located in the front of the lower leg and is responsible for dorsiflexion of the foot and ankle.

Example: Utilised in sports like running for foot clearance during the swing phase, in football for dribbling and change of direction, and in basketball for quick stops and pivots.

Triceps:

Function: The triceps brachii extend the elbow joint.

Example: Crucial in sports like swimming for propelling movements, in weightlifting for overhead pressing, and in tennis for backhand strokes.

Understanding the functions and roles of these muscles is essential for athletes to optimise performance, prevent injuries, and enhance overall physical conditioning.

Types of Muscle Contraction

Muscle contraction refers to the process where muscles generate force and cause movement. There are two primary types of muscle contraction:

Isotonic Contractions:

Isotonic contractions occur when a muscle contracts and changes length. There are two subtypes:

a. Concentric Contraction:

In concentric contraction, the muscle shortens as it generates force.

The origin and insertion points of the muscle move closer together, and the muscle becomes thicker.

Example: Lifting a weight during a bicep curl involves concentric contraction of the bicep muscle.

b. Eccentric Contraction:

Eccentric contraction occurs when the muscle lengthens while under tension.

The origin and insertion points move further apart.

Eccentric contractions provide control during the downward phase of movements and help resist the force of gravity.

Example: Lowering a weight slowly during a bicep curl involves eccentric contraction of the bicep muscle.

Isometric Contraction:

Isometric contraction happens when a muscle generates tension without changing length.

This occurs when the body is fixed in one position, and there is no movement.

Example: Holding a plank position involves isometric contraction of the core muscles.