I have taught Pilates for over 9 years and as a sports massage therapist for elite athletes, competitive and ex-professional sports people, I urge you to review your posture and the balance of your overall training.
Did you know that the spine is 40% stronger when posture is correct and the spine sits in a neutral, optimal position? Yes, I know it is very difficult to hold perfect posture while lunging at your opponent as a Hoplite, but applying the principle of good, well-balanced posture during your gym workouts and warm-ups will only add to the overall benefit of strengthening your core.
Simple techniques, such as keeping your eye line up as much as possible, chin parallel with the floor, rolling your shoulders up toward your ears, slowly moving the shoulder blades back into position nice and flat against the rib cage, this will then stretch and open the chest nicely.
Now lift up through the upper spine whilst retaining a natural curve in your lower back. Bingo good posture!