I got contacted by a personal message a couple of weeks ago by a regular reader of my blog asking me about how to strengthen the hips, lower back, and especially the hamstrings. This gentleman had a pretty lean amount of equipment at hand so he figured that I'd be able to assist him with how to do these with a modest set-up consisting of a suspension rig, a 110 lbs sandbag, an ab wheel, and a pull-up bar.
At first, I gave a very brief answer because I was short on time and the PM on the web site was giving me fits. When I started typing, I realized that I had a pretty good blog entry at hand and since he's a regular, I figured that he'd get the message here as well as there.
Now the obvious choice here, considering he has the sandbag is deadlifting the sandbag. I've slightly ameneded my belief that the deadlift is bad for you. Obviously, it's hard to argue a lift that you probably perform so much in real life will be the death of you. There are ways to deadlift that are okay and there are others that flat-out suck. Stiff-legged and round back deadlifts need not apply. There are also people who obviously do way too much deadlifting. Muscle imbalances and stress injuries don't make you strong or healthy.
Having said that, if you're doing most any leg exercise properly, you should be working your hamstrings and hips. For further explanation of what I'm talking about, we need a picture...
Remember, muscles move by pulling their ends together. So, if you're going to move the hips, you have to pull them downward with your hamstrings. So, the question becomes: when you squat, are you lowering your body in a controlled manner or letting gravity do the work for you? If you do any kind of squatting, or other leg work, keep this in mind.
Now, for the lower back, I've always liked doing different bridging exercises. One, very important detail about the muscles of the lower back (not just the Spinal Erectors but the deep stuff too) is they're made up mostly of slow-twitch fibers. There's a good reason for this: they're supposed to provide alignment all the time. Not difficult work but work but they're working for a long period of time. So, I like bridging because when you bridge, you have to hold the positon for an extended period of time.
Now, thanks to the work of Matt Furey, the bridge everyone thinks of when we hear the word in regards to strength training is the nose-to-mat, wrestlers bridge. Frankly, this exercise is controversal and scares the hell out of a lot of people but it's not the only bridge out there. There is the gymnastic bridge as well as the straight bridge. Both are good.
So, Jared, I hope that this answers some of your questions and points you in the right direction.