There are many different exercises which can be used to help TMD. Your Physiotherapist or Sports Massage Therapist will be in a better position to advise which are best for you, but here are a few examples that they may ask you to carry out.
Press your tongue to the roof of your mouth. Then place one index finger on your left TMJ and the other index finger on your chin. Apply light pressure on each finger, drop your chin so that your mouth opens, but tongue stays in contact with the roof of your mouth. Repeat with the right TMJ.
Stand or sit tall then bring your head backwards, tucking your chin in towards your chest. Keep your head straight, it might help to focus on a point or object straight in front of you.
Keep your jaw in a neutral position and then partially open it, about the width of the top of your thumb. Apply gentle pressure with your hand, first on the left then right then at the bottom of your jaw. Resist the pressure to keep your jaw stationary.