ONE LEGGED DEAD LIFTS:

Deadlifts are great for your hamstrings, butt and lower back, but form is critical and you should skip this exercise if you have any back problems.

To do this move, take the left leg back just a bit, lightly resting on the toe. With the weights in front of the thighs, tip from the hips and lower the weights as low as your flexibility allows. Keep your back flat or with a natural arch and make sure you keep the abs contracted to protect the back. Squeeze the glutes of the working leg to raise back up. Do 2-3 sets of 8-12 reps.

Note that your back leg does not have to remain straight like in this picture. It can remain bent with the toes at your ankle.