The hip is a common site of osteoarthritis. To help protect the hip joint from "wear and tear," it is important to strengthen the muscles that support it. Your hip also controls the position of your knee, and strengthening your hips may be one component of your rehab program for knee pain. Your physical therapist may also prescribe hip exercises after total hip replacement if you have a hip labrum tear or as part of your hip exercise program for hip pain.
Apply the above concept to your hips. When you sit, your hips are in a "flexed" position. Therefore, the muscles that flex your hips are in a shortened state. You probably spend at least a third of your day sitting down. Think about how much time those hip flexor muscles stay shortened. A lot. Over time, they become tighter and tighter until you look like the old man in the picture. So unless you want to look like that, perform the stretches shown below.
Kidneys — The kidneys are a matched pair. One painful kidney can cause back pain on one side or the other. Kidney pain can feel like back pain, and may occur on only one side. It is usually quite lateral, and just barely low enough to qualify as “low” back pain. However, when kidney stones descend through the ureters, they can cause (terrible) pain in the low back. Kidney stone pain is often so severe and develops so rapidly that it isn’t mistaken for a back pain problem.
Sit at the front of your chair with knees bent and feet flat, holding onto the sides for balance. You can do this exercise with eyes open. Or for deeper concentration and a balance challenge, try it with your eyes closed. With your knee bent, lift your right leg about six inches off the ground (or as far as you can). Hold for three counts, and then lower it back to the floor. Repeat with your left leg for one rep. Do 10 reps total.
Along with these exercises, it's also important to do some supplementary exercises to work your hip's supporting muscles. You've probably heard of your shoulder's rotator cuff. Well, your hip also has a cuff, or a group of muscles that help stabilize and support movement. For these exercises, you'll need a mini-band, a longer thera-band or tubing (both are sold at many sporting goods stores, or can be purchased online), and a cable-column unit.
A sedentary lifestyle can lead to having weak and tight hip flexors as they are always in the shortened position. Tight hip flexors can lead to a limited range of motion, poor posture, lower back and hip pain, and even injuries. These muscles need to get a workout when you are standing and doing movements such as raising your leg to climb stairs, run, or ride a bicycle.