Types of Muscle Contraction Explained
Muscle contraction is the process that allows muscles to produce force and create movement. In IB Sports, Exercise and Health Science (SEHS), students are required to understand the three main types of muscle contraction and how each contributes to movement and performance. These contraction types explain not only how movement occurs, but also how muscles control and stabilise the body during exercise.
Recognising and explaining these contractions clearly is essential for biomechanics questions in IB exams.
Concentric Muscle Contractions
A concentric contraction occurs when a muscle shortens while producing force. This type of contraction is commonly associated with the lifting or acceleration phase of a movement.
Key characteristics include:
- The muscle shortens
- Force overcomes resistance
- Movement occurs in the direction of muscle action
For example, during the upward phase of a bicep curl, the biceps shorten to lift the weight. In sport, concentric contractions are important for explosive movements such as jumping, sprinting, and throwing.
In IB SEHS exams, concentric contractions are often linked to force production and movement initiation.
Eccentric Muscle Contractions
An eccentric contraction occurs when a muscle lengthens while under tension. This happens when the muscle is controlling or slowing down a movement rather than producing it.
Key features include:
- The muscle lengthens
- Force is produced while resisting movement
- Movement occurs opposite to muscle action
For example, during the lowering phase of a bicep curl, the biceps lengthen while controlling the descent of the weight. Eccentric contractions are essential for deceleration, shock absorption, and injury prevention.
In sport, eccentric contractions play a major role in landing, changing direction, and controlling speed.
