Scanning Sports Medicine
Clinical Predictors of Foot Orthoses' Efficacy in Individuals With Patellofemoral Pain
Authors of this study in the September 2011 issue of Medicine & Science in Sports & Exercise® sought to identify those patients with patellofemoral pain syndrome (PFPS) who were most likely to benefit from foot orthoses (1). The aim of the study was to develop a clinical prediction tool that would help clinicians to identify those individuals with PFPS whose conditions would improve with the use of orthoses. The study consisted of 60 individuals with PFPS and who had an average age of 26 ± 5 yr. Each participant attended one treatment session where the prefabricated orthoses were provided. The orthoses were commercially available three-quarter-length devices with lateral cutouts, made of ethylene-vinyl acetate of medium density, with built-in arch supports and four degrees of varus rearfoot wedging. No customization was performed, but sizing was done to ensure that the first metatarsal phalangeal joint was just distal to the end of the orthoses. After 12 wk of wearing the orthoses, participants rated their perceived improvement in symptoms using a five-point Likert scale. Those reporting to have markedly better conditions were considered to have obtained a successful outcome with regard to developing the clinical prediction rule. Those reporting to have a moderately better, the same, moderately worse, or markedly worse condition were considered to have an unsuccessful outcome. Several baseline measures were collected before the use of orthoses, and an evaluation of the immediate changes to functional performance and footwear comfort was done. Fifty-seven participants completed the 12-wk study. Of them, 14 (25%) reported that their conditions were markedly better with the foot orthoses. The most predictive variables were immediate reduction in pain with wearing of orthoses during a single-leg squat, ankle dorsiflexion range of motion less than 41.3 degrees, usual pain less than 22.0 mm on a 100-mm visual analog scale, and footwear motion control properties score less than 5.0 (indicative of less support). When predictors were evaluated independently, reduction in pain with the foot orthoses during a single-leg squat produced the greatest prediction accuracy. The pretest probability for marked improvement increased from 25% to 45% when pain was reduced during a single-leg squat. Interestingly, the usual indicator used for prescribing foot orthoses is excessive foot pronation, and it was not found to be associated with efficacy of foot orthoses in this study. The authors did cite several limitations that may have contributed to this finding, including the exclusion of anyone who had worn orthoses in the past 5 years and the fact that customized orthoses were not used, which may have limited the success in those with significant pronation.
Bottom line: This study identified that the combination of three of four predictors (poor footwear motion control properties, less usual pain, reduced pain during a single-leg squat, and reduced ankle dorsiflexion range of motion) increased the probability of marked improvement with foot orthoses from 25% to 78%. This clinical prediction rule may help health care providers when considering foot orthoses prescriptions for their patients with PFPS.
Sports Supplement: Quercetin
The September/October 2011 edition of ACSM's Health & Fitness Journal® includes a review of the available research on quercetin supplementation in trained and untrained individuals (2). Quercetin is classified as a flavonoid, a phytonutrient found in a variety of fruits and vegetables. In vitro and animal studies have shown that quercetin possesses antioxidant, anti-inflammatory, antihypertensive, and anti-infectious properties that offer potential for the prevention and treatment of disease. More recent studies have attempted to demonstrate quercetin's ability to prevent or mitigate some of the adverse effects of intense exercise, as well as to enhance physical performance. Although data are limited, some evidence supports the theory that quercetin can augment some aspects of immune function and reduce upper respiratory tract illness rates in exercise-stressed athletes. The main proposed mechanism for enhanced physical performance while using quercetin is an increase in muscle mitochondria leading to improved aerobic endurance. Studies in mice have proven this theory, although studies in humans have yet to yield statistically significant results. The results also vary between trained and untrained individuals. Although the untrained subjects were more likely to demonstrate an effect, no data support a beneficial effect on sedentary individuals initiating an exercise program above and beyond that which can be achieved with exercise training alone. In addition, quercetin does not seem to provide performance benefits to individuals or athletes who are trained well already.
Bottom line: Research does not support a performance-enhancing effect of quercetin in physically trained individuals. It may or may not benefit physically untrained individuals. Quercetin supplementation still may offer a benefit in the reduction of upper respiratory tract illnesses for athletes, but cautious use of supplements must prevail if one is subject to testing for doping because the risk of contamination always exists.
1. Barton CJ, Menz HB, Crossley KM. Clinical predictors of foot orthoses efficacy in individuals with patellofemoral pain. Med. Sci. Sports Exerc.
2. Williams MH. Sports supplements: quercetin. ACSM Health Fitness J.