RESUMEN
OBJECTIVE: To identify physical and behavioral characteristics related to the incidence of tibial stress injuries (TSIs). DESIGN: Case-control study. No clinical care was conducted. SETTING: Research laboratories in the San Francisco (the United States) and Gold Coast (Australia) areas. PARTICIPANTS: Forty-eight patients (21 men and 27 women) with acute TSI, and 36 (16 men and 20 women) age-matched, sex-matched, height-matched, weight-matched, and activity-matched controls with no history of TSI. INDEPENDENT VARIABLES: Height, weight, body mass index, bone, lean and fat mass, lower limb alignment anomalies, foot type, orthotics, calcium, recent weight change, menstrual history, oral contraceptive use, medications, smoking, alcohol, sleep, training type, and intensity. Differences in continuous variables were tested using 1-way analysis of variance. Categorical variable comparisons were performed with Fisher exact test. MAIN OUTCOME MEASURE: Tibial stress injury. RESULTS: Tibial stress injury cases had 2.7% more fat (P < 0.001) and 2.6% less muscle (P < 0.001) as well as lower trochanteric bone mineral content (BMC) (P < 0.001), lumbar spine (LS) area (P < 0.001), femoral neck BMC (P < 0.001), length (P < 0.05), area (P < 0.001), cortical width (P < 0.01), cross-sectional moment of inertia (P < 0.001), and index of bending strength (P < 0.001) than controls. Controls had lower LS BMC (P < 0.01), length (P < 0.001), and broadband ultrasound attenuation (P < 0.001). The use of orthotic insoles was more prevalent in TSI cases than controls (25% vs 5.6%, respectively; P < 0.02), as were foot anomalies (56.3% vs 27.8%, respectively; P = 0.01). CONCLUSIONS: Tibial stress injury cases had lower lean and higher fat mass, a tendency for smaller bones, and for foot anomalies compared with uninjured matched controls. bone mineral density was normal for both groups. CLINICAL RELEVANCE: Enhancing lean mass and limiting gains in fat may provide some protection against TSI. Individuals with small skeletal frames are advised to increase training loads particularly gradually and to reduce training intensity at the first sign of pain in the shins.
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Fracturas por Estrés/epidemiología , Fracturas de la Tibia/epidemiología , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Factores de Riesgo , Adulto JovenRESUMEN
PURPOSE: To examine the relationship between severity grade for radiography, triple-phase technetium 99m nuclear medicine bone scanning, magnetic resonance (MR) imaging, and computed tomography (CT); clinical severity; and recovery time from a tibial stress injury (TSI), as well as to evaluate interassessor grading reliability. MATERIALS AND METHODS: This protocol was approved by the Griffith University Human Research Ethics Committee, the Stanford University Panel on Human Subjects in Medical Research, the U.S. Army Human Subjects Research Review Board, and the Australian Defense Human Research Ethics Committee. Informed consent was obtained from all subjects. Forty subjects (17 men, 23 women; mean age, 26.2 years ± 6.9 [standard deviation]) with TSI were enrolled. Subjects were examined acutely with standard anteroposterior and lateral radiography, nuclear medicine scanning, MR imaging, and CT. Each modality was graded by four blinded clinicians. Mixed-effects models were used to examine associations between image severity, clinical severity, and time to healing, with adjustments for image modality and assessor. Grading reliability was evaluated with the Cronbach α coefficient. RESULTS: Image assessment reliability was high for all grading systems except radiography, which was moderate (α = 0.565-0.895). Clinical severity was negatively associated with MR imaging severity (P ≤ .001). There was no significant relationship between time to healing and severity score for any imaging modality, although a positive trend existed for MR imaging (P = .07). CONCLUSION: TSI clinical severity was negatively related to MR imaging severity. Radiographic, bone scan, and CT severity were not related to time to healing, but there was a positive trend for MR imaging.
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Traumatismos en Atletas/diagnóstico , Fracturas por Estrés/diagnóstico , Tibia/lesiones , Fracturas de la Tibia/diagnóstico , Adulto , Femenino , Humanos , Puntaje de Gravedad del Traumatismo , Imagen por Resonancia Magnética , Masculino , Dimensión del Dolor , Tomografía de Emisión de Positrones , Factores de Tiempo , Tomografía Computarizada por Rayos X , Cicatrización de HeridasRESUMEN
OBJECTIVE: Whole body vibration is a potential therapy for age-related loss of musculoskeletal competence. Vibration has improved bone in animal models, but evidence in humans is limited. Relative efficacy of low- vs. high-intensity whole body vibration is also unknown. Our goal was to observe the effect of brief low- and higher intensity whole body vibration on risk factors for hip fracture in postmenopausal women. DESIGN: We used an 8-mo randomized controlled trial design to examine the influence of twice-weekly low-intensity whole body vibration (15 mins, 30 Hz, 0.3 g) or higher intensity whole body vibration (2 × 3 mins, 12.5 Hz, 1 g) on anthropometrics, bone (whole body, hip, spine, forearm, and heel), muscle (wall squat and chair rise), and balance (tandem walk and single leg stance). Physical activity, daily calcium, and compliance were recorded. Effects were examined by repeated-measures analysis of covariance, controlling for age, height, weight, calcium, physical activity, compliance, and baseline values. RESULTS: Forty-seven women (71.5 ± 9.0 yrs) completed the trial. There were no between-group differences in any measure at 8 mos, but within-group effects were evident. Controls lost bone at the trochanter (-6%, P = 0.03) and lumbar spine (-6.6%, P = 0.02), whereas whole body vibration groups did not. Whole body vibration subjects improved wall squat (up to 120%, P = 0.004) and chair rise performance (up to 10.5%, P = 0.05). CONCLUSIONS: Eight mos of twice-weekly whole body vibration may reduce bone loss at the hip and spine and improve lower limb muscle function. These changes may translate to a decreased risk of falls and hip fracture.