8周基础军训对入伍新兵红细胞及其相关指标的影响

目的探讨8周基础军训(basic military training,BMT)对入伍新兵血像中红细胞及其相关指标的影响,为指导科学的军事训练提供参考。方法数据来自新疆边防部队2015年度入伍的50名男性新兵,分别在BMT前后测定并记录受试新兵的红细胞计数、血红蛋白浓度及血清铁蛋白等。结果经过8周的BMT,新兵血液中血红蛋白浓度、红细胞计数及血清铁蛋白均显著下降(P0.05,P0.01)。结论 8周BMT可能导致入伍新兵发生运动性贫血,铁缺乏可能是其主要原因。     

推拿在高校体育实践中的运用状况

推拿在我国各大高校中已有初期运用,其在高校的体育实践课和运动健康方面的保障均有成功案例,这对高校体育实践产生了一定影响。本文通过对推拿在高校体育实践中运用状况的分析,从不同角度阐述这些应用的影响及作用,以及推拿对于高校体育发展的意义。     

Arthroscopy of the knee in children and adolescents

A retrospective review was done of 69 children and adolescents (7-17 years old) who underwent 75 arthroscopies of the knee during a 5-year period. Girls were overrepresented (71%). Thirty-eight were children under the age of 16. Of 46 injuries, 34 (74%) happened during sports. Children and adolescents were divided into two age groups based on their presumed state of skeletal maturity (boys 9–15 and girls 7–14 in group I and boys 16–17 and girls 15–17 in group II); meniscal lesions were equally common in the two groups, whereas anterior cruciate ligament tears were more common in older children (NS). Eleven of 17 (65%) anterior cruciate ligament lesions were combined with other intra-articular pathology, most often meniscal tears (9/11). As in other studies, half of the prearthroscopic diagnoses were incorrect. A high frequency of incorrect prearthroscopic diagnoses and of combined lesions justifies arthroscopy as an important diagnostic tool in children and adolescents with a history of twisting knee injury or chronic nonspecific knee problems. Girls practising ball games seem to be especially prone to knee injuries leading to arthroscopy.     

The effect of laser refractive surgery on the on-field performance of professional baseball players.

BACKGROUND: The aim of this study was to determine the effect of laser refractive surgery on the offensive performance of professional baseball players. METHODS: Extensive search of the public media was conducted to determine which major league baseball players had undergone laser refractive surgery and when the procedure was performed. Baseball performance data were then used to determine presurgery and postsurgery baseball performance averages. A total of 17 position players were identified; however, 5 of these players were not considered in the analysis owing to insufficient playing experience either before or after the laser procedure. RESULTS: No statistically significant or practically significant difference was found between the presurgery and postsurgery means on either on-base percentage (P = 0.31), batting average (P = 0.39), slugging percentage (P = 0.66) or on-base plus slugging (OPS; P = 0.997) of major league baseball players. CONCLUSIONS: These preliminary findings suggest that professional baseball players should not expect a laser refractive surgical procedure to significantly improve their offensive baseball performance, despite the elimination of glasses or contact lens wear.     

Injuries in national karate competitions in Finland

The injuries sustained in 6 national karate competitions in Finland were studied by analyzing data from 450 bouts during the season 1991–1992. The analyzed data included a personal interview with each competitor and detailed information on the bouts and any injuries sustained. The overall probability of injury was 0.28 per bout. These injuries occurred to 16% of the 647 competitors. Occurrence of injury was greatest among adult men, which was pronounced in final bouts. Of all injuries diagnosed by the physicians for the competitions, more than 95% were localized to the head. The majority of these were minor injuries. Experienced competitors were more injury-prone than beginners. On the other hand, none of the background factors studied significantly affected the probability of injuring one's opponent. Most injuries and penalties, as well as full scores, were caused by direct punches to the head. From these findings it was concluded that a protective guard for the head together with modification of competition rules could significantly reduce injuries.     

Why do long-distance runners not have more bone? A vital biomechanical explanation and an estrogen effect

Inanimate structures cannot detect and repair their fatigue damage or microdamage, so to minimize it they need more structural material and strength. Living bone handles this matter differently. Bone modeling drifts adapt bone architecture and strength to the loads on bones in ways that tend to keep strains from exceeding a “modeling threshold” range. Strains (or equivalent features) above that threshold switch mechanically controlled modeling ON. Where strains stay below that threshold, this modeling goes OFF. Repeatedly loading-deloading a bone causes microdamage in it, and basic multicellular unit (BMU)-based bone remodeling normally repairs it. Where strains stay below an operational “microdamage threshold,” remodeling can repair whatever microdamage happens for as long as it happens. Strains above that threshold can cause too much microdamage to repair completely and lead to fatigue fractures of trabeculae or whole bones. The modeling threshold normally lies comforably below the microdamage threshold. Since modeling normally adjusts bone architecture to keep strains from exceeding the modeling threshold, this keeps strains below the microdamage threshold, too, and voluntary activities do not cause more microdamage than remodeling can repair. Therefore, long-distance runners do not need more bone mass and strength than nonrunners of comparable age, sex, and body size.