If you recall my last article (Aug. '08), I spoke about muscular balance and how offsetting this natural equilibrium can alter spinal position. It is virtually impossible to be in perfect anatomical position every minute, but we can reverse a lot of the damage our daily routines cause. The key is to use exercises that specifically target the muscle groups responsible for poor posture. Another great way to combat poor anatomical alignment is to switch arms or sides in whatever you're doing. For example, if you have a baby, switch the arm that you hold her with or carry the car safety seat in the other arm. When you grocery shop, evenly load your bags into both arms if you're carrying them. Women should switch the shoulder they carry their pocketbook on, and so on. Try challenging yourself to use your nondominant side in every daily task if you can: It'll make a difference.
I've compiled a few exercises here that should help combat the negative effects of constantly sitting (like on a bike). They're safe when performed correctly, but you should always consult your physician before beginning any exercise program.
As the name implies, this first exercise "undoes" sitting. It shortens up the back and leg muscles that stretch during sitting and lengthens the abs and chest muscles.
Reverse Sitting
Start by standing with your hands straight up overhead, your feet shoulder width apart and slightly turned out. Slowly squat down by bending at the knees, bring your arms down in front of you, and lower yourself until your hands touch the floor. As you stand, keep your arms straight and begin to move them upwards so that in the finished standing position your hands are back up over your head. At the top of this movement you want to move your hips forward slightly to stretch the abdominal wall. Perform three sets of 15-20 repetitions. As you get stronger, try holding a dumbbell in your hands to add resistance.
This next exercise addresses imbalance of your body's sides while also promoting back health.
Reverse Sitting 1 | 
Reverse Sitting 2 | 
Reverse Sitting 3 |