Deadlifts are great on a BOSU because you really have to isolate your hamstrings and, by having to balance on the ball at the same time, you're targeting that hamstrings in two different ways.
So in order to do the deadlift on a BOSU ball, you stand on it. Again, right in the middle. And you just want to reach forward, butt goes back. Now, the important part to remember in this is that you're sending your hips and butt back, you're not just dropping forward. So the reason my chest comes forward is because I am sending my hips backward. Just like that. And then if you want to make it a little bit more intense, you add weights.
So you don't want to go too far down. A lot of people you'll see in the gym may be going all the way down to here, but that's not really good for your back. So the best thing to do is to go until you can't stop, until you can't go any further. So once your hips hit a point where they can't go back any further, that's when it's time to come up.
And then another thing you can do, is do it on the other side which is a little bit more difficult and advanced but it will target the hamstrings that much more. So step on to the ball, feet hip width apart. And on this side you want to keep a slight bend in your knees because you're balancing. And then you just, again, come forward and back. And just until the hips can't go back any further. Then you lift right back up.
And that would be some hamstring exercises you could do on the BOSU ball.