Define isotonic and isometric contractions.

Isotonic and isometric contractions are two different types of muscle contractions that occur during physical activity.

Isotonic Contraction:

Isotonic contractions involve the change in length of a muscle as it contracts and generates force.
In an isotonic contraction, the tension in the muscle remains constant, but the length of the muscle changes. This results in movement of a joint.
There are two types of isotonic contractions:
a. Concentric Contraction: In this type, the muscle shortens as it contracts. For example, when you perform a bicep curl and lift a weight, your bicep muscles undergo concentric contractions.
b. Eccentric Contraction: In this type, the muscle lengthens as it contracts. For example, when you slowly lower a weight during a bicep curl, your bicep muscles undergo eccentric contractions.
Isometric Contraction:

Isometric contractions involve the generation of muscle force without a change in the length of the muscle or joint movement.
During an isometric contraction, the muscle contracts, but the overall length of the muscle remains the same, and there is no joint movement.
Isometric contractions are often used for activities that require stability and maintaining a position, such as holding a plank position or pressing against an immovable object.
In summary, isotonic contractions involve changes in muscle length and result in joint movement, while isometric contractions involve muscle contractions without changes in muscle length or joint movement. Both types of contractions have their respective uses in various forms of exercise and physical activities.