[Matt]

Here are some ideas for you:

- hyperextensions (progressing towards weighted hyperextensions)

http://www.exrx.net/WeightExercises/...extension.html

- deadlifts

http://www.exrx.net/WeightExercises/...BDeadlift.html

The hypers are rather simple as you can tell from the illustration. They do a great job working the entire lower back and hamstrings. You'll find that most hamstring exercises work the lower back and vice versa.

Be very careful though if you do deadlifts as form is extremely important - poor form/using too much weight can cause serious problems. However if done correctly deadlifts are one of the ultimate compound exercises as they work basically the entire back and utilize lots of leg involvement (amount of hamstring involvement depends on stance though - wide stance brings hamstrings more into play, narrow stance brings more back into play). I personally like deadlifts because they trump doing a multitude of isolation work.

As a final point, remember that the lower back is opposite your abdominals. If the loewr back and abs are out of balance as far as strength and conditioning goes then it's not a good thing. Just note that some ab work is preferable with any workout program but especially when trying to strengthen your back.