The second time people do a tough arm workout, their muscles show less 'swelling' on ultrasound scans, meaning there's probably less damage or inflammation.

The more the biceps stretched during the first workout, the more 'swelling' showed up on the ultrasound scan afterward.

When you do bicep curls with your shoulder stretched back, the lower part of your bicep shows more signs of stress on ultrasound right after the workout than when you keep your shoulder neutral.

The middle part of your bicep gets a little more 'hazy' on ultrasound after a workout, but it clears up by the next day — and it doesn’t matter if you changed your shoulder angle.

Doing bicep curls with your arm stretched behind you makes the lower part of your bicep feel more strained right after the workout than doing them with your arm at your side.

After doing blood flow-restricted exercise, the ultrasound images of muscles didn’t show any change in texture with different cuffs, but when more pressure was applied, the images suggested the muscle tissue became slightly more watery.