They also can’t control their reflexes, which is why many newborns engage in seemingly spastic movements and clench their fists. This might worry you, but is it really cause for concern? Here’s ...

The next time you do a resistance workout, stop and clench the muscle before you finish the lift. Do it for every lift. For example, with a biceps curl, clench the biceps when your arm is curled up ...

When Dr. Priya Mistry asks people if they clench their jaws, they usually say no—yet she can see clear signs suggesting otherwise. So now, she words the question differently: Are they aware of their ...

British researchers cautioned that getting blood donors to tightly clench their fists during the procedure may raise potassium levels in the samples, which may indicate kidney or heart problems.