The Effects of Multi-Day vs. Single Pre-exercise Nitrate Supplement Dosing on Simulated Cycling Time Trial Performance and Skeletal Muscle Oxygenation.

Jo, E, Fischer, M, Auslander, AT, Beigarten, A, Daggy, B, Hansen, K, Kessler, L, Osmond, A, Wang, H, and Wes, R. The effects of multiday vs. single pre-exercise nitrate supplement dosing on simulated cycling time trial performance and skeletal muscle oxygenation. J Strength Cond Res 33(1): 217-224, 2019-A transient augmentation in the metabolic efficiency of skeletal muscle is the purported basis for dietary nitrate supplementation amongst competitive and recreational athletes alike. Previous studies support the ergogenic effects of nitrate supplementation, as findings indicated improved microvascular blood flow, exercise economy, and performance with relatively short-term supplementation. As with most ergogenic aids, the optimum duration of supplementation before performance or competition, i.e., loading phase, is a critical determinant for efficacy. Therefore, the purpose of this study was to investigate the effects of long-term vs. single dosing nitrate supplementation on skeletal muscle oxygenation and cycling performance. In a randomized, placebo controlled, double blind, parallel design study, healthy, recreationally active men (n = 15) and women (n = 14) subjects (age = 18-29 years) completed an 8 km (5 mi) simulated cycling time trial before and after a 14-day supplementation period with either a nitrate supplement (Multi-Day Dosing Group) (n = 14) or placebo (Single Pre-Exercise Dosing Group; SD) (n = 15). Both groups consumed a single dose of the nitrate supplement 2 hours before the post-treatment time trial. In addition, skeletal muscle oxygenation was measured via near-infrared spectroscopy during each time trial. Multiday nitrate supplementation significantly decreased time to completion (p = 0.01) and increased average power (p = 0.04) and speed (p = 0.02) from pre-to post-treatment, while a single dosing produced no significant changes to these measures. There were no significant differences over time and across treatments for any other measures including muscle oxygenation variables. Overall, long-term nitrate supplementation appears to have an advantage over a single pre-exercise dosing on cycling performance and metabolic efficiency as indicated by an increase in power output with no change in oxygenation.

X-ray features to predict ankle fracture mechanism.

INTRODUCTION: The genetic Lauge-Hansen classification has been traditionally used for reconstruction of the mechanism of ankle injury. The ability of the Lauge-Hansen classification to predict actual mechanism of the injury has been questioned in recent studies, leaving a void in medicolegal reasoning. The aim of this study is to identify morphologic features of malleolar fractures on plain X-rays that may be used to reveal the fracture mechanism. MATERIAL AND METHODS: Radiographs of 78 patients with acute malleolar fractures were analyzed and compared with fracture mechanisms reported by these patients. RESULTS: A modified Pankovich classification of medial malleolus fractures and the presence of a posterior malleolus fracture were able to significantly predict the mechanism of fracture reported by the patient (p<0.05). Lateral fracture morphology was not useful for predicting the fracture mechanism except for infrasyndesmotic fractures pointing to a supination mechanism. CONCLUSION: A supination mechanism of the fracture can be predicted by observing pure ligamentous or chip-avulsion deltoid injury. The presence of an anterior colliculus fracture of the medial malleolus is correlated with a pronation mechanism. A fracture of the posterior malleolus correlates with pronation while an intact posterior malleolus correlateds with supination as a fracture mechanism. Absolute determination of fracture mechanism from the X-ray morphology of the fracture is impossible in the majority of cases.