Skeletal and Muscular Systems: Functional Roles of Muscles and Types of Contraction

Functional Roles of Muscles

Muscles play several roles within the body including producing movement, maintaining posture, stabilising joints and generating heat.
The production of movement happens through the contraction and relaxation of muscles working alongside the skeletal system.
Posture maintenance is the ability of muscles to keep the body in positions that allow us to perform daily activities.
Muscles perform the role of joint stabilisation by providing tension around the joints, which also aids in preventing injuries.
Through the process of muscular contraction, muscles are able to generate heat to help maintain normal body temperature.

There are mainly two types of contractions in the muscular system: isotonic and isometric contractions.
Isotonic contractions occur when the length of the muscle changes as it contracts. It is subdivided into concentric and eccentric contractions.
- In concentric contractions, the muscle shortens as it contracts, such as during the lifting phase of a bicep curl.
- During eccentric contractions, the muscle lengthens as it contracts, like during the lowering phase of a bicep curl.
Isometric contractions involve the muscle contracting without changing its length, such as holding a plank position in exercise.
Understanding the type of contraction and how it impacts movement can be beneficial in maximizing performance and preventing injuries.

The human body consists of three main types of muscle fibres: Type I, Type IIa, and Type IIb.
Type I fibres, also known as slow-twitch fibres, are fatigue resistant, have a slow contraction speed and are utilised for endurance activities.
Type IIa fibres, also known as fast oxidative, have a fast contraction speed, are used in both endurance and power activities, and have a moderate resistance to fatigue.
Type IIb fibres, also known as fast glycolytic, have the fastest contraction speed, fatigue easily, and are used for short, high-intensity activities like sprinting.
It’s important to note that an individual’s distribution of different muscle fibre types can impact their performance in different physical activities.