4 FOR THE CORE, EXERCISE 3: BACK BRIDGE
Lying on the back with knees bent at 90 degrees, arms extended sideward at 45 degrees, with head and feet on the marching surface, perform the drawing-in maneuver. Once the abdominal contraction is established, raise the hips off of the ground until the trunk and thighs form a generally straight line. The spine must not arch to achieve this position. With the buttocks still up, straighten the left leg until it aligns with the trunk and thigh. Don’t let the trunk and pelvis sag on the unsupported side. Hold five seconds, and then switch to the other leg. Repeat for one minute. If the spine begins to sag, arch, or tilt, lower to the starting position, rest for 3 to 5 seconds, then, try again (Figure 6-8). The goal is to maintain the back bridge position for 60 seconds alternating leg raises as needed.