Spinal Side Bending and Swimming

About one year ago, Dr. John introduced a radical notion that side bending was critical to elite backstroke.  This hidden move is possibly one way to maximally engage the latissimus dorsi during the catch and pull.  Recent installments in the Spine Biomechanics series (Part I, Part II, Part III) have reinforced this concept.  As Dr. John wrote last year,

“the lats cause shoulder extension, adduction and internal rotation as well as side bending (aka lateral flexion) at the thoracic and lumbar spine via their attachment to the thoracolumbar fasica and sacrum. This side bending will connect one whole side of the body and bring the shoulder and hip together. Approximation of the shoulder and hips on one side will cause the spine to move from a straight line to a 'C'.” (See Lats on Lats)

As a result of side bending, many elite backstrokers will appear to “wiggle” through the water, despite the common belief that any lateral motion is anathema to stroke efficiency.  Although there is little (if any) published research specific to this point, a close look at video can easily confirm that side bending and a slight wiggle are common in elite backstroke.  This point was central Dr. John’s previous article.  So one year later, what can we add to this point?

1) Spinal rotation is only one component of rotational sports.  A look to other sports reveals similar spine biomechanics used to optimize power.   While each rotational sport has its own properties, we all use the same anatomy and physiology to perform basic movement patterns. 

2) For example, golfers long believed that the golf swing turned around a fixed spine titled forward at a constant angle.  However, modern imaging has shown that in each swing (for a right handed player), the spine goes through one full cycle of left side bend + extension, returns to neutral (flexion), and then finishes to other side with right side bend + extension. 

3) Bending during a swing cycle allows for additional power to be generated through lift forces, not only rotary forces.  In fact, advanced motion capture tools have shown that each joint can move through at least SIX planes of motion, not only the traditional three.

4) Moving through additional planes of motion allows for additional torque, so that greater force is generated than by flexion, extension, or rotation alone.  When these patterns occur simultaneously, the body can create more power than if it only relied on one or two planes within each joint.        

5) In skilled athletes, the transition from one side to the other results in a buildup of stored energy to be released during each stroke cycle.  Remember our discussion of the Serape Effect, which described the interconnectedness of the opposite side hip to opposite side shoulder.  Think of each “sling” as a rubber band that can be pulled tight and then released.

6) A similar phenomenon exists in baseball, in which pitchers’ lead shoulder will rise higher than the trail shoulder, before reversing this pattern as the pitcher releases the ball.  In other words, the throw is not simply a rotation back and rotation but a combination of flexion/extension, rotation, and side bending. 

7) While golf and baseball are not exact comparisons to swimming, side bending is a potentially untapped power source when applied correctly.  Understanding global biomechanics may also help treat injuries by reinforcing the point that the body is interconnected as a single functional unit.  Rather than chasing isolated rotator cuff exercises, we must strive to improve our understanding of the full body mechanics that alter shoulder stress.    

8) Side bend has often been vilified due to the common view from the deck of swimmers wiggling their hips, snaking across the entire lane.  Proficient swimmers hide this very well due to the elegance with which they slice through the water.  The missing key here may be lateral hip stability and excessively tight hip flexors that prevent swimmers from exploiting the side bend. 

Conclusion

As we know, in swimming, a more powerful stroke means little if power is cancelled out by drag.  However, for now, it is useful to recognize that side bending is not an illusion and may be an untapped power source consistent with optimal spine biomechanics.  Ultimately, these concepts should make us rethink conventional wisdom on how the spine works during long axis freestyle, particularly backstroke.    

By Allan Phillips. Allan and his wife Katherine are heavily involved in the strength and conditioning community, for more information refer to Pike Athletics.