Sometimes I feel like I need to carry around a dictionary with me while I’m at the gym. There are so many different terms for things. For now, I am going to give you the 411 (does anyone even use that term anymore?) on ISO…. metric and tonic.
The most common type of muscle contraction is called isotonic, which refers to the shortening of the muscle as it contracts. For example, during biceps curls, the biceps muscles contract against gravity and shorten, drawing the forearm toward the upper arm.
Isometric contractions occur when a muscle contracts against an immovable object. For example, when you push against a brick wall, the muscle in your legs and upper body will contract but no shortening occurs.
Every weight training exercise involves a combination of both types of contraction. The muscle being exercised contracts isotonically, while many of the stabilizing muscles contract isometrically. In the biceps curl, the biceps exhibit isotonic contraction, while the lower back and thighs contract isometrically to support your body.
Whether it’s isometric or isotonic contracting , as long as you are working your muscles and challenging your muscles, they will reward your efforts by making your body look strong and tone. Watch out bikinis, here we come!