ABSTRACT:Introduction: Stress fractures (SFx) are one of the most common and debilitating overuse injuries seen in military recruits, and they are also problematic for nonmilitary athletic populations. The goal of this randomized double-blind, placebo-controlled study was to determine whether a calcium and vitamin D intervention could reduce the incidence of SFx in female recruits during basic training. Materials and Methods: We recruited 5201 female Navy recruit volunteers and randomized them to 2000 mg calcium and 800 IU vitamin D/d or placebo. SFx were ascertained when recruits reported to the Great Lakes clinic with symptoms. All SFx were confirmed with radiography or technetium scan according to the usual Navy protocol. Results: A total of 309 subjects were diagnosed with a SFx resulting in an incidence of 5.9% per 8 wk. Using intention-to-treat analysis by including all enrolled subjects, we found that the calcium and vitamin D group had a 20% lower incidence of SFx than the control group (5.3% versus 6.6%, respectively, p ‫ס‬ 0.0026 for Fisher's exact test). The per protocol analysis, including only the 3700 recruits who completed the study, found a 21% lower incidence of fractures in the supplemented versus the control group (6.8% versus 8.6%, respectively, p ‫ס‬ 0.02 for Fisher's exact test). Conclusions: Generalizing the findings to the population of 14,416 women who entered basic training at the Great Lakes during the 24 mo of recruitment, calcium and vitamin D supplementation for the entire cohort would have prevented ∼187 persons from fracturing. Such a decrease in SFx would be associated with a significant decrease in morbidity and financial costs.

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Objective Claudication is the most common manifestation of peripheral arterial disease, producing significant ambulatory compromise. The purpose of our study was to evaluate patients with bilateral lower limb claudication and characterize their gait abnormality based on advanced biomechanical analysis using joint torques and powers. Methods Twenty patients with bilateral claudication (ten with isolated aortoiliac disease and ten with combined aortoiliac and femoropopliteal disease) and sixteen matched controls ambulated on a walkway while three dimensional biomechanical data were collected. Patients walked before and after onset of claudication pain. Joint torques and powers at early-, mid-, and late-stance for the hip, knee and ankle joints were calculated for claudicating patients before and after the onset of claudication pain, and were compared to control subjects. Results Claudicating patients exhibited significantly reduced hip and knee power at early-stance (weight acceptance phase) due to decreased torques produced by the hip and knee extensors. In mid-stance (single limb support phase), patients had significantly reduced knee and hip power due to the decreased torques produced by the knee extensors and the hip flexors. In late-stance (propulsion phase), reduced propulsion was noted with significant reduction in ankle plantar flexor torques and power. These differences were present before and after the onset of pain with certain parameters worsening in association with pain. Conclusions The gait of claudication is characterized by failure of specific and identifiable muscle groups needed to perform normal walking (weight acceptance, single limb support and propulsion). Parameters of gait are abnormal with the first steps taken, in the absence of pain, and certain of these parameters worsen after the onset of claudication pain.

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The results of this analysis suggest that self-rated Tanner pubertal staging is not influenced by age and is not a reliable method of assessing Tanner stage.