The overhead lunge is a great lower body and stability exercise. Your quadriceps, glutes and hamstrings will be working through the lunge movement, whilst your core and shoulders work to stabilise you.
Set up by taking the bar into the body with hands only just wider than shoulder width apart. From here, press the bar into the air, so that your arms are extended straight above your head. You can then either step forwards or backwards to do forwards or reverse lunges - just make sure you do the same on each leg!
Throughout the exercise make sure your shoulders stay back so that the bar remains above your head and does not start to creep forwards. Your front knee should not extend in front of your toe and you should be looking straight ahead.