By Scott Lucett, MS, NASM-CPT, PES, CES
Senior Research Director, National Academy of Sports Medicine
Dysfunction at the foot and ankle complex can lead to a variety of musculoskeletal issues in other regions of the kinetic chain that can eventually lead to injury. In this article, we’ll review the common postural distortion pattern, Pronation Distortion Syndrome, its effects on the kinetic chain, and corrective solutions to decrease injury risk.
Pronation distortion syndrome is characterized by excessive foot pronation (flat feet) with concomitant knee internal rotation and adduction (“knock-kneed”). This lower extremity distortion pattern can lead to a chain reaction of muscle imbalances throughout the kinetic chain, leading to foot and ankle, knee, hip and low back pain.
It has been shown that excessive pronation of the foot during weight bearing causes altered alignment of the tibia, femur, and pelvic girdle (Figure 1) and can lead to internal rotation stresses at the lower extremity and pelvis, which may lead to increased strain on soft tissues (Achilles tendon, plantar fascia, patella tendon, IT-band) and compressive forces on the joints (subtalar joint, patellofemoral joint, tibiofemoral joint, iliofemoral joint, and sacroiliac joint), which can become symptomatic (1,2). The lumbo-pelvic-hip complex alignment has been shown by Khamis to be directly affected by bilateral hyperpronation of the feet. Hyperpronation of the feet induced anterior pelvic tilt of the lumbo-pelvic-hip complex (3). The addition of 2-3 degrees of foot pronation lead to a 20-30% increase in pelvic alignment while standing and 50-75% increase in anterior pelvic tilt during walking (3). Since anterior pelvic tilt has been correlated with increased lumbar curvature, the change in foot alignment might also influence lumbar spine position (4). Furthermore, an asymmetrical change in foot alignment (as might occur from a unilateral ankle sprain) may cause asymmetrical lower extremity, pelvic, and lumbar alignment, which might enhance symptoms or dysfunction. An understanding of this distortion pattern and its affects throughout the kinetic chain becomes particularly important for recreational runners and walkers as the accompanying stressors to the soft tissues and joints can lead to Achilles tendonitis, plantar fasciitis, IT-band syndrome, and low back pain.
When assessing for pronation distortion syndrome, both static and dynamic assessments can be done. When performing either a static or dynamic assessment, have the individual take their shoes off and make sure you have the ability to see their knees as well. During a static assessment, from an anterior and posterior view, look to see if the arches of their feet are flattened and/or their feet are turned out. When performing a dynamic assessment, such as the overhead squat, look to see if the feet flatten and/or turn out and if the knees adduct and internally rotate (knee valgus). These compensations can also be assessed both from an anterior and posterior view. For many, it’s easier to see excessive foot pronation from a posterior view in comparison to an anterior assessment, so assessing in both positions can help in confirming your findings.
Corrective Exercise Strategies for Pronation Distortion Syndrome
Functionally tightened muscles that have been associated with pronation distortion syndrome include the peroneals, gastrocnemius, soleus, IT-band, hamstring, adductor complex, and tensor fascia latae (TFL). Functionally weakened or inhibited areas include the posterior tibialis, anterior tibialis, gluteus medius and gluteus maximus. Following NASM’s Corrective Exercise Continuum programming strategy can help address these muscle imbalances that may be contributing to the distortion pattern (5). First, inhibit the muscles that may be tight/overactive via self-myofascial release. Key regions that should be addressed would include the peroneals, gastrocnemius/soleus, IT-band/TFL, bicep femoris and adductor complex.
The next step is to lengthen the tight muscles via static stretching. Key muscles to stretch include the gastrocnemius/soleus, TFL, bicep femoris and adductor complex. Hold each stretch for a minimum of 30 seconds perform 1-2 sets of each stretch.
Once the overactive muscles have been addressed, activate the underactive muscles. Key areas to target with isolated strengthening are the anterior tibialis via resisted dorsiflexion, posterior tibialis via a single-leg calf raise, gluteus medius via wall slides and gluteus maximus via floor bridges. Perform 1-2 sets of 10-15 repetitions.
Finally, perform an integrated exercise to improve muscle synergy to enhance neuromuscular efficiency and overall movement quality. An example integration exercise would include a multiplanar single-leg balance reach while maintaining neutral foot and knee alignment. Perform 1-2 sets of 10-15 repetitions.
Pronation distortion syndrome is a common lower extremity postural distortion pattern that can lead to other movement dysfunction patterns throughout the kinetic and ultimately injury. By incorporating static and dynamic assessments of the foot and ankle complex can help to identify this distortion pattern. Once identified, following a systematic corrective exercise strategy can help to improve functionality and movement quality, leading to decreased risk of injury.
- Powers, C.M. (2003). The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. Journal of Orthopedic & Sports Physical Therapy, 33:639-46.
- Powers, C.M., Chen, P.Y., Reischl, S.F., & Perry, J. (2002). Comparison of foot pronation and lower extremity rotation in persons with and without patellofemoral pain. Foot & Ankle International, 23:634-40.
- Khamis, S., & Yizhar, Z. (2007). Effect of feet hyperpronation on pelvic alignment in a standing position. Gait Posture, 25:127-34.
- Levine, D., & Whittle, M.W. (1996). The effects of pelvic movement on lumbar lordosis in the standing position. Journal of Orthopedic & Sports Physical Therapy, 24:130-5.
- Clark, M. C., & Lucett, S. C. (2011). NASM Essentials of Corrective Exercise Training. Baltimore, MD: Lippincott, Williams and Wilkins.