Isotonic & Isometric Contractions

Let's talk about isotonic versus isometric contraction .

Uh When you learn a new language , it's so easy to get really confused .

Isotonic versus isometric isotonic gives you a real little hint in there .

It has the word tonic or tone in there .

When we talk about contractions , it's all about the muscle moving .

When we look at isotonic contraction , there's actually two kinds of contractions underneath .

There's an eccentric contraction and a concentric contraction , concentric contraction is what we use all the time when we're at the gym .

So let's take biceps brachii as our classic example .

I want you to feel it .

It's this muscle here .

A lot of times we do bicep curls there .

It is .

Its origin is on the super glenoid tubercle and the cor coid process , its insertion is the radial tuberosity on the radius .

When you feel that muscle belly and we get those muscle fibers to shorten and that's its job .

Its action is flexion of the elbow when we get it to shorten and you feel a bunch up underneath there , that's concentric contraction , concentric contraction , shortening of the muscle fibers .

Now let's go in the opposite direction .

It's working while those muscle fibers are getting longer and lengthening .

So when we look at isotonic contraction , we have concentric contraction and still working .

The muscle is still working .

We have centric contraction .

Now , when we think about isometric contraction , this is where you can take a cup of water , watch the joint angle .

It's gonna stay the same biceps still engaged .

And if I start to fill up that water , I'm gonna fill it up right to the top .

Is my muscle still working ?

Absolutely .

It's still working .

The muscle is contracting joint angles not changing .

So we see this all the time in yoga actually where you hold a pose and then the muscle fatigues because it's working for a long period of time .

So , isometric contraction is more muscle work applied more load , but no joint change under isotonic concentric contraction and eccentric contraction under isometric , maintaining joint angle , but increasing the workload .