UNDERSTANDING THE LOWER KINETIC CHAIN AND HOW IT CAN AFFECT ATHLETES
It may not be a surprise to know that throwing and overhead athletes experience a multitude of shoulder and elbow injuries. But would it surprise you to know that weakness or limited endurance in the core and lower body, or even foot type could be contributing to shoulder or elbow pain, dysfunction, or injury in overhead athletes?
The body functions as what we like to call a kinetic chain. This means that when the body moves, each part plays a role in producing or transmitting force to the next adjacent joint to achieve the desired movement. The same is true in the case of throwing and overhead athletes. Thus, everything that happens from the foot all the way up to the hand can contribute to shoulder and elbow injury. It all depends on where the dysfunction lies in the kinetic chain.
A few potential areas of dysfunction in the kinetic chain include:
1. The Pes Planus Foot or “Flat Foot”
The Pes Planus foot type is more flexible and unstable than normal which makes it a poor producer and transmitter of force. Since the foot is the initial factor in generating force up the chain (Campbell et al. 2010), a poor contribution from the foot increases the demand up the kinetic chain to compensate for that loss of force production, which can result in injury.
2. Lower Extremity Weakness
A study performed by Plummer et al. (2018) found that the lower extremity has a 50 percent contribution to overhead activity. If the lower body is weak, that contribution percentage drops and the demand on the shoulder and elbow increase significantly.
3. Trunk Weakness
The trunk acts as the connection between the upper and lower body. A study by Kibler et al. (1995) found that a “20 percent reduction in transfer of kinetic energy from hip and trunk to upper extremity requires an 80 percent increase in mass or 34 percent increase in rotational velocity at the shoulder to produce the same resultant force.” So, even if the lower body does a great job at playing its role in generating force, if the trunk is too weak to transmit that force up the chain, it can bring us back to square one, placing more demand on the shoulder and elbow.
4. Fatigue and Repetitive Stress
Fleisig et al. (2009) state that “no matter how poor a pitcher’s mechanics or how deleterious a certain variety of pitches may be, injury is the result of repeated insult to the elbow joint and never one single throw to the plate.” The same rings true for the shoulder and for all overhead and throwing athletes.
In order to minimize repetitive stress injuries, it is important to address weak links found within the kinetic chain, improve endurance, ensure that proper mechanics are maintained even in a state of fatigue, and most of all, ensure that periods of rest (especially for year-round athletes) are factored into training and playing regimens as much as possible.
How Core Physical Therapy Can Help
So where does physical therapy come into play? We are the experts at analyzing movement, identifying the weak links, and developing a customized treatment plan to address the needs of each unique individual that walks through our doors! Let us help you get back to the game you love and keep you there!
Questions? Need an Appointment? Contact Core Physical Therapy today!
1) Campbell BM, Stodden DF, Nixon MK. Lower extremity muscle activation during baseball pitching. Human Kinetics Publishers, INC.; 2010:964.
2) Fleisig GS, Weber A, Hassell N, Andrews JR. Prevention of Elbow Injuries in Youth Baseball Pitchers. Current Sports Medicine Reports (American College of Sports Medicine). 2009;8(5):250-254.
3) Kibler W. Biomechanical analysis of the shoulder during tennis activities. Clinics In Sports Medicine. January 1995;14(1):79-85.
4) Plummer H, Oliver G, Powers C, Michener L. Trunk lean during a single-leg squat is associated with trunk lean during pitching. International Journal Of Sports Physical Therapy. February 2018;13(1):58-65.