• When muscles contract, they pull their ends towards the body's center. Think of a rubber band being pulled from both ends.
• They can move our body parts by changing the force of contraction and the angle of action.

 Concentric Contraction

• Definition: Muscle shortens as it overcomes resistance.
• Real World Example: Think about doing a bicep curl. As you lift the weight up (overcoming the weight's resistance), your bicep muscle shortens.

 Isometric Contraction

• Definition: Muscle contracts but doesn't change in length because the force from the muscle is equal to the resistance.
• Real World Example: Imagine pushing against a wall with all your might. The wall won't move (unless you're a superhero), and your muscles are working but not shortening!

 Eccentric Contraction

• Definition: Muscle lengthens while contracting because it's not strong enough to overcome the resistance.
• Fun Fact: This type of contraction can produce more force than concentric contraction.
• Real World Example: Think about slowly lowering that weight during a bicep curl. Your bicep muscle is still working, but it's lengthening.

 Isotonic Contraction

• Definition: Muscle changes in length while maintaining the same tension. However, the term can be misleading.
• Real World Example: Imagine lifting a grocery bag. As you pick it up, the weight stays the same, but the force in your muscle might change due to the changing angle of your arm.

 Isokinetic Motion

• Definition: The muscle contracts, making a body part move at a constant speed around a joint. This is rare and typically requires special equipment.
• Real World Example: Imagine a specialized treadmill that controls your speed strictly. No matter how hard you try, you can only run at the speed it allows.