Correcting biomechanical imbalances for your athletic patients can help decrease lower extremity injuries and spinal complaints

Almost all competitive and recreational sports impose high levels of force and repetitive stress on the lower extremities. The most common sport-related injuries occur at the foot and ankle. Therefore, athletes will need to be evaluated for abnormal foot biomechanics. Chiropractic care includes the adjustment and support of any dysfunction and imbalances that are found. Whether they are walking, running, or playing golf, active patients need expert care.

Gait-way to Balance
Biomechanical problems in the feet cause lower extremity symptoms, and are also a major factor in recurrent spinal subluxations. The foundation provided by the feet must bear the weight of the entire body—and considerably more during running and other sport. If there is insufficient or inadequate support from the pedal foundation, the lower extremities and spine will be exposed to abnormal stresses and strains that eventually cause injuries, subluxations, and back pain.

When some part of the foot is not moving properly—either insufficient or excessive joint motion—the resulting forces produce effects up the kinetic chain into the leg and spine. Lysholm and Wiklander wrote an article for the American Journal of Sports Medicine: “Alteration of normal foot mechanics can adversely influence the normal functions of the ankle, knee, hip, and even the back.”¹

Virtually all foot biomechanical problems are related to either too much or not enough pronation during the stance phase of gait. Whether the foot goes too far into pronation or stays too supinated, the effects are felt from the toes to the spine. Katoh writes “A high-arched (cavus) foot with limited range of motion attenuates shock poorly, and a hypermobile flat foot also does poorly on shock attenuation because of its function near the end of the range of motion.”²

Some studies have helped us understand why this is so important for athletes:

Overload injuries. Subotnick performed a retrospective study that looked at the characteristics of athletes who reported recent foot and leg overuse problems, and compared them with a control group.³ The researchers were interested in finding whether excessive pronation while standing or running correlated to a higher possibility of developing various types of overload sports injuries.

The study group was made up of 66 injured athletes who ran at least once a week and needed treatment for iliotibial band syndrome, Achilles tendinitis, stress fracture of the tibia, tibial periostitis, and plantar fasciitis (overuse or overload injuries). A control group of 216 athletes were matched who did not have any symptoms of overuse injuries. The amount of pronation during standing and running at regular speed was determined by measuring the angles of their footprints (plantar prints).⁴

Figure 1. Checking patient’s medial arch in the standing position.

Busseuil found a significant correlation—those athletes with more pronation had a much greater likelihood of having sustained one of the overuse athletic injuries. While both the standing (static) and running (dynamic) prints showed some correlation, the amount of pronation seen in the static weight bearing footprint was the most predictive of developing an overuse injury. This study reminds us that it is very important to athletic performance and for injury prevention to check the alignment of patients’ feet in the standing position (Figure 1).

Knee pain and foot alignment. In another study, Freychat performed a visual assessment of the feet of 77 athletes while they were standing.⁵ After classifying the feet as obviously pronated, obviously supinated, or neutral, the investigators inquired into the history of knee pain. Those athletes who answered “yes” to the question of knee pain were more than twice as likely to have an abnormal foot alignment. In fact, this study found that “athletes with excessively pronated or supinated foot types may be more susceptible to knee pain than athletes with neutral foot types.”⁵ Both types of abnormal foot biomechanics are associated with a greater tendency to develop knee problems. Since knee injuries can often ruin an athlete’s aspirations, controlling pronation and absorbing the shock of supination are very important for many athletic patients.

Anterior cruciate ligament (ACL) rupture. When Dahle compared 50 subjects who had sustained an arthroscopically diagnosed rupture of their ACL with 50 uninjured matched controls, they found a higher risk of injury to the ACL in those with hyperpronation.⁶ He concluded that abnormal foot alignment predisposed an athlete to knee injury.

Athletes’ Feet
Every athlete should be checked for abnormal foot biomechanics. Whether a foot tends toward hyperpronation or excessive supination, undue forces are transmitted into the spinal joints. The combination of adjustments, exercises, and orthotics will improve performance, stabilize spinal subluxations, and help prevent lower extremity injuries.

Adjusting foot subluxations. When the foot is not functioning smoothly, especially excessive pronation (the most common biomechanical foot problem), specific adjustments are needed. Table 1 lists the usual foot subluxations seen with excessive pronation. I use standard adjusting methods to adjust areas that are found to be misaligned. The extremity adjusting system is useful for most athletes.⁷

Flexibility and strength exercises. Active procedures to improve the flexibility and strength of the surrounding musculature can speed response to care. I find the following procedures useful and time efficient:

• Golf ball—massage the entire plantar surface of the foot.
• Achilles stretch—press into the wall doing the runner’s stretch.
• Towel scrunch—use a small towel to pull in and push out with the toes while sitting.
• Resistance tubing—perform isotonic strengthening of the foot and ankle supports (Figure 2).

Figure 2. Ankle rehabilitation with exercise tubing.

Correcting imbalances between adjustments. Orthotics can help with biomechanical problems for long-term support. A properly designed and custom-fitted orthotic will provide the following corrections throughout the day and during all athletic activities:

• Shock absorption from viscoelastic materials eases the impact at heel strike and reduces the forces on all weight bearing joints.
• Decreasing the extent and speed of pronation reduces the medial rotation force that is transmitted into the knees and spine.
• Improved alignment and mobility of the arches with less muscle and connective tissue stretch provides more accurate proprioception for better balance and alignment.
• Reducing calcaneal eversion with a pronation wedge and supporting the medial arch limits the dropping of the pelvis during gait.

Mark N. Charrette, DC, lectures and writes on chiropractic biomechanics and orthopedics and has taught more than 140 seminars during the past 15 years. He is currently in practice in Las Vegas. Charrette can be reached via email: mncdc@aol.com. 

References
1. Lysholm J, Wiklander K. Injuries in runners. Am J Sports Med. 1987;15:168–171.
2. Katoh Y. Biomechanical analysis of foot function during gait and clinical applications. Clin Orthop Rel Res. 1983;177:23–33.
3. Subotnick SI. Forces acting on the lower extremity. In: Sports Medicine of the Lower Extremity. New York: Churchill Livingstone; 1989:189.
4. Busseuil C. Rearfoot-forefoot orientation and traumatic risk for runners. Foot & Ankle International. 1998;19:32–37.
5. Freychat P. Relationship between rearfoot and forefoot orientation and ground reaction forces during running. Med Sci Sports Exerc. 1996;8:225–232.
6. Dahle LK. Visual assessment of foot type and relationship of foot type to lower extremity injury. J Orthop Sports Phys Ther. 1991;14:70–74.
7. Beckett ME. Incidence of hyperpronation in the ACL injured knee: a clinical perspective. J Athl Train. 1992;27:58–62.
8. Charrette MN. How I adjust the excessively pronated foot. Success Express. 2000;20(3):31–34.