RESUMEN
[Purpose] The aim of study was to examine incidence of injury according to location of injury to develop an injury prevention program for elite badminton players of junior high school, high school, and university. [Participants and Methods] We conducted a prospective longitudinal study, between April 2012 and March 2013, on 133 national-level badminton players attending junior high school, high school, and university. Injury rates in athletes per 1,000 exposures were calculated based on gender and school age for the five most common injury locations, in addition, severity, type and circumstance were investigated. [Results] Injury rates in athletes per 1,000 exposures were the highest in the racket-side (RS) shoulder/clavicle among the female university students (4.35), RS thigh of high school females (2.21), and lumbar spine/lower back of males of all school ages and junior high school females (1.83-1.25). Significantly higher injury rates were noted for the overuse of the lumbar spine/lower back and RS shoulder/clavicle, trauma of the RS thigh and ankle, and injury, when compared with slight injury of the RS ankle. [Conclusion] Injury prevention programs should be developed for RS shoulder/clavicle overuse in university females, RS thigh trauma in high school females, and lumbar spine/lower back in males of all school ages and junior high school females.
RESUMEN
BACKGROUND: Injury prevention programs have recently been created for various sports. However, a longitudinal study on badminton injuries, as assessed by a team's dedicated medical staff, at the gymnasium has not been performed. OBJECTIVES: We aimed to perform the first such study to measure the injury incidence, severity and type as the first step in creating a badminton injury prevention program. PATIENTS AND METHODS: A prospective, longitudinal survey was conducted between April 2012 and March 2013 with 133 national tournament-level badminton players from junior high school to university in Japan with the teams' physical therapists at the gymnasium. Injury incidence was measured as the injury rate (IR) for every 1,000 hour (1000 hour) and IR for every 1,000 athlete exposures (1000 AE). Severity was classified in 5 levels by the number of days the athlete was absent from practice or matches. Injury types were categorized as trauma or overuse. RESULTS: Practice (IR) (1,000 hour) was significantly higher in female players than in male players; the rates increased with increasing age. IR (1,000 AE) was significantly higher in matches than in practice in both sexes of all ages, except for female junior high school students and injuries were most frequent for high school students in matches. The majority of the injuries were slight (83.8%); overuse injuries occurred approximately 3 times more than trauma. CONCLUSIONS: This is the first study in which medical staff assessed injuries in badminton, providing value through benchmark data. Injury prevention programs are particularly necessary for female university students in practice and high school students in matches.
RESUMEN
In most mammals, the optic nerve fibers are myelinated in its extraocular part (EON) but not in its intraocular part (ION) and also in the retina. Transitional zone from the myelinated to unmyelinated optic nerve usually lies in the central part to the lamina cribrosa. It has been known that dogs contain exceptionally myelinated fibers in ION by light microscopy. The aim of this study was to investigate electron microscopically the retino-optic nerve junction in dogs and re-evaluate the barrier to migration of oligodendroblasts into ION. Fourteen adult dogs were used. EON was largely myelinated. In ION the percentage of myelinated fibers decreased gradually toward the retina. A narrow area of ION adjoining the retina was completely unmyelinated. In most mammalian optic nerves, oligodendrocytes are not found in ION. It has been suggested that oligodendroblasts are prevented from migrating from EON into ION; that is to say, there is a barrier to migration of oligodendroblasts. The lamina cribrosa, a dense meshwork of fibrous astrocytic processes, and a defect in the blood optic nerve barrier have been proposed as a candidate for the barrier to migration. Our results suggest, however, that these factors, at least in dogs, would be not involved in the formation of a barrier to migration of oligodendroblasts.