What are some good exercises I can do to strengthen my lower back?
Deadlifts, backsquats and the press i.e. standing overhead press, NOT benchpress. You will inherently strengthen your back and core while performing these lifts as these areas (back and core) are required to maintain stability during the lifts.
12 Answers
If you have access to a gym, try doing lower back hyperextensions. Also, just as good is working on your core. Even doing simple planks will help that area out.
Deadlifts, backsquats and the press i.e. standing overhead press, NOT benchpress. You will inherently strengthen your back and core while performing these lifts as these areas (back and core) are required to maintain stability during the lifts.
Let me start by saying I am not a personal trainer and I do not have a medical background. That being said I am very active, in great shape and have spent tons of time working with trainers and researching proper techniques, etc.
Unless you are a body builder or professional weightlifter you probably don't need to focus on just one area of your body. You should create a weekly plan that gives you a good full body workout. You are far more likely to get hurt or injure yourself if you are focusing too heavily on one muscle group while ignoring it's counterparts.
So for your lower back, remember that having a strong core is just as important as having a strong lower back and in fact the two go hand in hand.
It is always a good idea to warm up before starting any type of exercise (especially your lower back) and remember to always start easy and give yourself plenty of recovery time. Now that that's out of the way, this site lists several great back exercises. I would take a look at each one, decide what your needs are and create a plan based on that. Just remember to start slow and practice good form - when starting any workout plan it's more important to have good quality form than to be killing yourself lifting too much.
Barbell - "Good Morning"
http://www.exrx.net/WeightExercises/Hamstrings/BBGoodMorning.html
Start off with a VERY LIGHT WEIGHT. This is a great exercise for your lower back, but like any back exercise, not one you should jump into. (Bruce Lee supposedly hurt his back trying to be a superhero during this exercise)
Another good exercise is what I call cat and camels. This video is a good demonstration:
http://www.youtube.com/watch?v=CXRsjICsGnc
The goal is to engage your core and keep your abs tight when doing this. By doing this exercise, you will ensure that your core muscles (back and front) all start to engage smoothly whenever you're performing any activities, and will help take care of any lower back pain due to tightness or muscle imbalances.
James V. has it right here... Ken does not. I do have medical experience, and I was a collegiate rower and then went on to row for the national team. Rowing requires a strong but flexible back, and serious back injuries are common and career ending.
All of the strength & conditioning coaches, and team physicians said that roman chair exercises (what back extensions are) are the worst things you can do to prevent injury. We did alot of cobra, superman, alternating bridge and medicine ball work.
I've known about the "Prone Cobra" for a while, and did a search to show you a video and actually turned out two more in one video - Prone Cobra, Superman, and Alternating Bridge: http://www.ehow.com/video_2351308_the-prone-cobra-superman-alternating.html