A contributing factor to running injuries is our modern lifestyle.. the fact that most of us sit for hours on end--at our desks, at our computers, watching TV, or whatever. All this sitting can cause muscle imbalances, which develop over time--weakened deep abdominals, tight hip flexors, weak glutes and hips, tight hams, weak quads.
Doing a few simple exercises and stretches several times a week can help counterbalance the sitting. Here are a few you probably already know:
Bridges (for glutes, hams, core) - Lie on your back, arms by your sides, knees bent with feet flat on floor, feet directly under your knees. Contract deep abs and butt muscles, then raise your hips up, creating a straight line from knees to shoulders. Keeping your navel pulled in toward spine hold for a count of 10, then slowly lower your body back down and relax. Repeat for a total of 10-15 reps.
Hip Flexor Stretch - Kneel on left knee with right foot out in front in the 'lunge' position, with left hand reaching up toward ceiling. Contract deep abs (navel in toward spine) and roll pelvis backward. Lean forward into the lunge so that you feel the stretch in your left hip flexors. Hold 20-30 seconds. Repeat on other side. Do 3 times each side.
Cat Stretch (for lower back) - Kneel on hands and knees, spine in neutral position. Round your back up, like a cat stretching, pushing your mid-back up toward ceiling as high as you can. Hold for a count of 10. Repeat 5 or so more times.