Excessive compression of the lateral articular surfaces is frequently a major component of patellofemoral dysfunction. Many subjects exhibiting symptoms of this disorder have structural deviations throughout the lower extremity which combine to produce malalignment of the patellofemoral joint. Included in these malalignment factors is excessive pronation of the subtalar joint. Excessive rotation of the lower leg which accompanies subtalar joint pronation has been cited as a major contributor to patellofemoral dysfunction. Although the excessive rotation of the lower leg will disrupt the normal mechanics of the tibiofemoral joint, the specific link between tibial rotation and patellofemoral symptoms has not been established. This paper presents a theoretical model which describes the compensation that can occur at the tibiofemoral joint to deal with the excessive tibial rotation. The link between the tibiofemoral compensation and increased patellofemoral compression is delineated. Factors which determine whether this increased compression becomes symptomatic are discussed. J Orthop Sports Phys Ther 1987;9(4):160-165.

This article presents the most common structural foot deformities encountered in clinical practice. The deformities are defined, and the expected compensations at the subtalar joint (STJ) are described. The theoretical consequences of the STJ compensations on proximal and distal tissues are presented. A biomechanical rationale for certain tissue disorders is described. The possible effects of abnormal STJ compensation on osseous development are briefly discussed.

Initially reserved for rehabilitation programs, unstable surface training (UST) has recently grown in popularity in strength and conditioning and general exercise scenarios. Nonetheless, no studies to date have examined the effects of UST on performance in healthy, trained individuals. The purpose of this study was to determine the effects of 10 weeks of lower-body UST on performance in elite athletes. Nineteen healthy, trained members (ages 18-23 years) of a National Collegiate Athletic Association Division I collegiate men's soccer team participated. The experimental (US) group (n = 10) supplemented their normal conditioning program with lower-body exercises on inflatable rubber discs; the control (ST) group (n = 9) performed the same exercises on stable surfaces. Bounce drop jump (BDJ) and countermovement jump (CMJ) heights, 40- and 10-yard sprint times, and T-test (agility) times were assessed before and after the intervention. The ST group improved significantly on predicted power output on both the BDJ (3.2%) and CMJ (2.4%); no significant changes were noted in the US group. Both groups improved significantly on the 40- (US = -1.8%, ST = -3.9%) and 10-yard sprint times (US = -4.0%, ST = -7.6%). The ST group improved significantly more than the US group in 40-yard sprint time; a trend toward greater improvement in the ST group was apparent on the 10-yard sprint time. Both groups improved significantly (US = 2.9%, ST = -4.4%) on T-test performance; no statistically significant changes were apparent between the groups. These results indicate that UST using inflatable rubber discs attenuates performance improvements in healthy, trained athletes. Such implements have proved valuable in rehabilitation, but caution should be exercised when applying UST to athletic performance and general exercise scenarios.

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A medial post may be a potential means to decrease risk of anterior cruciate ligament injury.