Swing Speed: From the Floor, Through the Core, Part I
Joe Bonyai, CSCS
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Swing Speed: From the Floor, Through the Core, Part I
Joe Bonyai, CSCS |
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Breakdown of Rotation Ground based rotational movements like throwing, swinging, and striking all follow the same sequence. Force is generated in the lower body and transmitted through the torso, into the arms, hands, and implement. For a more detailed analysis and corresponding EMG data, see Shaffer et al. (1993). Shaffer and colleagues used a baseball player as their subject; however, this sequence does not only apply to one sport. Here’s Rafael Nadal demonstrating a similar pattern:
1 à 2 à 3
Photo 1) Preparation – Nadal starts in a base athletic position with his weight biased on the trail leg. Knees, hips, and shoulders are perpendicular to the target. Photo 2) Drive – Weight shift into the front side through extension, abduction, and lateral rotation of the trail hip and simultaneous rotation of the pelvis towards the target. Shoulders remained perpendicular to or slightly turned away from the target. Photo 3) Contact – Full extension of the trail hip with plantar flexion of the ankle and simultaneous uncoiling on the torso. From a view in the coronal plane, you would see shoulder-hip-knee alignment. Those are the fundamentals, not including the follow through. To further examine the details of each phase of the swing, let’s take a joint-by-joint look at some at the critical anatomy of rotational movement. The Foot/Ankle Trail Leg During the preparation and drive phases, the trail foot and ankle create the foundation for the trail leg to push into the ground. As you can see from Photo 2 above, Rafa requires good closed dorsiflexion range of motion to keep his trail foot grounded for an effective push-off. Lead Leg Restriction in the lead ankle will “refer” mobility to the knee and hip. Studies examining the effect of ankle bracing reveal that restriction of the ankle will lead directly to increased rotation at the knee during landing and trunk turning (Venesky, Docherty, Dapena, & Schrader, 2006; Santos, McIntyre, Foecking, & Liu, 2004). During swinging movements, the lead ankle must have good range of motion into supination as you can see in the photos below:
The Hip and Knee Loading Phase or Back Swing During the early phase of rotational movements, the hips must be able to dissociate from one another. For pitchers and other throwing athletes (Mariano, below), this allows the trail hip and knee to get full extension, and the lead leg to land with good hip-knee-ankle alignment with the foot pointed towards the target. During a backswing or loading phase (Tiger, below), hip dissociation allows the back leg to maintain a strong position to push into the ground, and minimizes the arc through which the front knee will have to move as it extends during the swing. With the feet grounded, this “dissociation” relies on a combination of dynamic hip stability as the torso rotates atop the femurs. This enforces the importance of designing closed kinematic chain hip mobility progressions into your program (more to come in Part II).
Follow Through Optimal hip mobility during the follow through spares the sacroiliac joint and lumbar spine from accepting the torsional load. Lack of total rotational range of motion of the lead hip has been related to low back pain in professional golfers and recreational athletes who participate in rotation-related sports (Harris-Hayes, Sahrmann, & Van Dillen, 2009; Vad, et al. 2004). Look at the ways in which the torso rotates around the hip in each of these pictures:
The Lumbar Spine/Pelvis The lumbo-pelvic-hip complex serves as the junction between the upper and lower extremities. A stable lumbar spine and pelvis literally establishes a safe foundation on which the rest of the joints can operate. This junction must be stable throughout the each phase of the swing:
It may seem hypocritical that as important as the core is, it gets the smallest description and no pictures of it “in action”. That’s because 1) the importance of core stability has been covered so much recently, 2) all of the descriptions and pictures in this article are dependent upon optimal core stability, so in fact, every single description and picture in this piece is dedicated to the core at work. The Thoracic Spine The “shoulder turn” in the golf swing or any rotational movement is driven by mobility of the thoracic spine. To summarize briefly, the thoracic spine is permitted to rotate due to the configuration of the articular surfaces of the superior and inferior facets (zygapophyseal joint) on each vertebrae. The angle of the lumbar vertebral articular facets restricts rotation. Just like the ankle and hip, restriction in the thoracic spine will alter the mechanics of other areas above and below it. The X-Factor Rotation of the thoracic spine allows for what is generally termed “the X-factor”. Take a look at the first picture below. With the highly technical Microsoft Paint, I estimated a line through Tiger’s contralateral AC joints and anterior superior iliac spines. If you were to look at this picture from above, the two neon green lines would form an “X”. This dissociation creates a stretch around the torso, and of the muscles and fascia connecting the contralateral hip and shoulder. The greater the stretch, the greater the reflex action and subsequent swing speed.
Improving extension
of the thoracic spine is critical to optimize rotation and functioning of
the trunk muscles. Hyperkyphosis or “rounding” of the upper torso brings
the rib cage closer to the pelvis, which alters the length-tension
relationships and coordination of all the muscles surrounding the trunk.
Not only does hyperkyphosis inhibit proper mechanics of adjacent
vertebrae, but also inhibits the muscles that pull the upper torso into
rotation. Overall strength and range of motion is reduced – not a good
combo. In the second picture above, notice Tiger’s torso remains erect
during the backswing. Also, as demonstrated in the photos below, mobility
of the T-spine will spare other structures (shoulder, lumbar spine) during
the follow through:
Thoracic posture is not only important for rotational movement, but general performance as well. The position of the ribcage in relation to the pelvis affects respiratory function. All of the muscles that attach to the rib cage play either a primary or accessory role in respiration. Altered length-tension relationships of these muscles due to poor posture may inhibit optimal breathing and recovery. Conclusion and Part II: More Walk, Less Talk That’s enough anatomy, it’s time to train. In Part II, I’ll outline the exercises and progressions that will help prepare the body for rotation-related sports. Part II will include isolated and integrated exercises that will improve mobility, stability, and durability of the joints reviewed above. I’ll then finally get to the interesting stuff: designing programs for rotational athletes and the “X-factor” when it comes to training rotational athletes – actually teaching multi-segmental rotary mechanics.
References Harris-Haynes, M., Sahrmann, S. A., & Van Dillen, L. R. (2009). Relationship between the hip and low back pain in athletes who participate in rotation-related sports. Journal of Sport Rehabilitation, 18. McGill, S. (2006) Ultimate back fitness and performance. Backfitpro, Waterloo, Ontario. Santos, M. J., McIntyre, K., Foecking, J., & Liu, W. (2004). The effects of ankle bracing on motion of the knee and hip joint during trunk rotation tasks. Clinical Biomechanics, 19. Shaffer, B., Jobe, F. W., Pink, M., & Perry, J. (1993). Baseball batting: An electromyography study. Clinical Orthopaedics and Related Research, 292. Vad, V. B., Bhat, A. L., Basrai, D., Gebeth, A., Aspergren, D. D., & Andrews, J. R.(2004). Low back pain in professional golfers: The role of associated hip and low back range of motion deficits. American Journal of Sports Medicine, 32, 2. Venesky, K., Docherty, C. L., Dapena, J., & Schrader, J. (2006). Prophylatic ankle braces and knee varus-valgus and internal-external rotation torque. Journal of Athletic Training, 41, 3.
Nadal Sequence http://static.zooomr.com/images/269594_7833a9defa.jpg http://static.zooomr.com/images/269593_642661f696.jpg http://static.zooomr.com/images/269592_be575665f8.jpg Agassi Image http://www.teachingtennis.com/coach/ds2backhand.htm Pujols Image Tiger Follow through Image http://i2.cdn.turner.com/cnn/2008/images/08/21/t1soft.tiger.woods.gi.jpg Rivera Image http://imagecache.allposters.com/images/pic/PHO/AAFV007%7EMariano-Rivera-Pitching-Posters.jpg Tiger backswing http://farm1.static.flickr.com/239/445649108_2eabbe3631.jpg Lincecum Image http://pinoylife.com/wp-content/uploads/2008/11/lincecum.jpg Field Hockey Image http://www.astroturfnews.com/images/fieldhockey09.jpg Djokovic Image http://news.xinhuanet.com/english/2008-09/03/xin_29209050314579062204734.jpg Tiger Backswing 2 http://img.timeinc.net/golf/i/instruction/2008/04/TigerAtTheTop_299x225.jpg Hamels Image http://www.60ft6in.com/images/hamels.jpg Pedroia Image http://blogs.trb.com/sports/baseball/blog/dustin-pedroia-ap2.jpg Souray Image http://hockeytalks.com/wp-content/uploads/2007/09/sourayoiler.jpg
Joe Bonyai CSCS, is currently completing his Master’s degree in strength and conditioning from Springfield College is and co-director of Empower Athletic Development, located in Scarsdale, NY and ready to open in June 2009. Joe can be easily contacted at jjbonyai@hotmail.com
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