In all kinds of exercise — swimming, biking, lifting, running — a strong and connected core makes you more efficient, which means faster and less likely to suffer an overuse injury. My Equinox swim coach Hannah is tweaking my stroke, but the most effective change by far is my rib cage. She wants it up and forward, which interestingly enough is the same postural correction I received from Danny Dreyer, creator of Chi Running, when I studied with him last Spring. Since I'll be unable to get into the pool before our next session, Hannah told me to work on my ribs and posture — to lengthen my torso and lift my chest.
Yes! I can cross train at my desk, while walking my daughter to school, and when doing the dishes. When I leave the slouching behind and lift my ribs, not only am I taller, but I feel my upper abs engage. I call that a double bonus. Are you slouching right now? Try a little desk cross training and sit up straight, with the ribs over the pelvis not behind it, and engage your abs. This should help your aching back too.