Do you work out the same direction every day? For example, are most of your exercises focused on moving forward (like running, walking, cycling or the elliptical machine)? Even bicep curls are focused on your front, and not your back. Neglecting your back and sides can create muscle weakness and put you at risk for injury.
You can easily fix this problem adding work in different directions. If you’re a runner, try backward running or walking drills, as well as side-step drills. If you swim laps, try the backstroke instead of the breaststroke. To strengthen sides, try standing lateral leg raises to work the outer thigh. For the shoulders, do lateral dumbell presses.
Rotational movements are great too, as long as you perform them in slow, controlled manner. Try what I call the apple-picker: Stand with the legs hip-width apart, swing both arms up together to one side, pick an apple off the tree, then swing them down to the opposite side to put it in the basket behind you while pivoting the feet.
If you do a lot of exercises to strengthen your abdominal muscles, it’s important to strengthen the opposing muscles in the back. Lat pulls on a machine are great for the mid-back. Supermans work the lower back: lie on your stomach on the floor with legs and arms extended. Then lift the legs and arms off the floor together while balancing on the abs. You’re flying!
Changing your routine to include work in different directions will give you a more balanced body and reduce your chances of injury.