00:01 So now let's switch gears again and talk a little bit about different types of muscle contractions that can occur. 00:08 So you have isotonic muscle contractions. 00:11 In which the tension is constant while the muscle length is changing. 00:17 If the muscle length gets smaller, it is referred to as a concentric isotonic contraction. 00:24 And if the muscle length increases, it is referred to as an eccentric isotonic contraction. 00:33 The other type of muscle contraction is isometric. 00:37 And this we contract the muscles but we do not change the length. 00:42 A good example of this is doing wall sits. 00:46 So, as you can see in this demonstration, we're looking at both concentric and eccentric isotonic contractions. 00:55 So as they move the weight up toward the shoulder, they're exhibiting a concentric contraction. 01:01 The muscle length is shortening as the muscles contract. 01:05 As we move the weight back down toward the hip. 01:08 This is an eccentric contraction. 01:10 And this case the muscle length is lengthening and the muscle is contracting. 01:16 Now, we are exhibiting isometric contractions. 01:21 And this demonstration, the weight is just being held and has not moved. 01:26 The muscles are still having to contract in order to hold the weight up, but there's actually no change in the length of the muscle.
The lecture Skeletal Muscle Contractions: Types (Nursing) by Jasmine Clark, PhD is from the course Musculoskeletal System – Physiology (Nursing).
When a student nurse is carrying several heavy textbooks, the biceps remain in a fixed position. What type of muscle contraction is this called?
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