Effects of physical activities that induce moderate external loading on bone metabolism in male athletes

Sports characterized by little or moderate weight bearing or impact have a low osteogenic effect. However, the action of such sports on bone turnover remains unclear. The objective of this study was to determine the effect on bone remodelling of physical activities that induce moderate external loading on the skeleton. Thirty-eight male athletes aged 18–39 years (cyclists, n?=?11; swimmers, n?=?13; triathletes, n?=?14) and 10 age-matched sedentary controls aged 22–35 years participated in the study. The study combined measurement of bone mineral density by dual-energy X-ray absorptiometry and bone turnover assessment from specific biochemical markers: serum bone-specific alkaline phosphatase, osteocalcin, urinary type I collagen C-telopeptide and calcium. Compared with the controls and swimmers, adjusted bone mineral density was higher (P?<?0.05) in triathletes at the total proximal femur and lower limbs. No differences in bone mineral density were found between cyclists, swimmers and controls. Compared with controls, osteocalcin was higher (P?<?0.05) in triathletes and swimmers and urinary type I collagen C-telopeptide was higher in swimmers only. Serum bone-specific alkaline phosphatase was lower (P?<?0.05) in cyclists than in all other groups. In conclusion, an osteogenic effect was found only in triathletes, mainly at bone sites under high mechanical stress. Bone turnover differed in athletes compared with controls, suggesting that bone turnover may be sport-practice dependent. Despite some encouraging observations, it was not possible to show that changes in the bone remodelling process were sport-discipline dependent.     

男子武术套路运动员有氧代谢能力的研究

采用自动气体分析仪和遥测心率计对20名男子武术套路运动员的有氧代谢能力进行了研究。结果表明:优秀男子武术套路运动员的最大摄氧量达3 6±0 32L/min(60 9±4 23ml/kg·min);无氧阈摄氧量占最大摄氧量的79 8%,接近优秀耐力性项目运动员水平;但一般水平武术套路运动员同比则有显著差异,提示武术基础训练中应注意加强有氧代谢能力训练,以有助于耐力素质的全面提高。     

Children's frequency of participation in moderate to vigorous physical activities

Third and fourth grade boys (n = 422) and girls (n = 390) in four Texas elementary schools reported their participation in moderate to vigorous physical activities (MVPAs) over a 3-day period. Students were surveyed during class on successive days. On a subsample (n = 44), the agreement between reported and observed physical activities during physical education or recess was 86.3%. Running, walking fast, games and sports, and bicycling accounted for 70% of Total MVPAs. Of Total MVPAs reported, 47.0% for boys and 44.6% for girls were 10 min or longer in duration (LMVPA). The average number of LMVPAs per day was 1.7 for both boys and girls. Students reported significantly more occurrences of LMVPAs out of school than during school. Significant interaction between grade and gender indicated that third grade boys reported more Total MVPAs and LMVPAs than third grade girls, but fourth grade boys reported fewer Total MVPAs and LMVPAs than fourth grade girls reported fewer Total MVPAs and LMVPAs than fourth grade girls. During the 3-day reporting period, 12.3% of boys and 13.3% of girls reported no LMVPAs, and 35.6% of boys and girls reported fewer than one LMVPAs per day. While the majority of children reported obtaining at least some activity daily, a substantial proportion of children in this sample reported fewer than one LMVPA daily, indicating that many children may not be obtaining adequate amounts of physical activity.     

我国优秀男子散打运动员身体功能训练研究

探讨身体功能训练在我国优秀男子散打运动员的应用实践效果,采用随机对照实验设计对我国24名优秀男子散打运动员进行为期16周、每周3次、每次60 min的身体功能训练。结果显示:(1)在基本运动能力方面,实验组在平板支撑、仰卧脚撑瑞士球平板支撑、悬吊侧卧平板支撑(左和右两侧)、单腿站平衡垫、瑞士球静蹲、坐位体前屈7项指标上较对照组有非常显著性改善(P<0.01);(2)在一般运动能力方面,实验组在400 m跑、单足4级跳、立卧撑3项指标上较对照组有显著性提高(P<0.05),在Illinois跑、高翻、卧推、深蹲等4项指标上较对照组有非常显著性提升(P<0.01);(3)在专项运动能力方面,实验组在10 s冲拳、10 s侧踹2项指标上较对照组有显著性提高(P<0.05),在30 s变向击打靶、30 s夹背摔假人、单次鞭腿击打力量、10 s腿法击打力量、10 s拳腿组合击打力量5项指标上较对照组有非常显著性提升(P<0.01)。结果表明:优秀男子散打运动员实验组的身体功能训练方案相对于对照组传统力量训练方案,强化了运动员的核心稳定性,优化了动作模式,加强了核心力量及其传输效率,对发展散打运动员的身体功能效果更佳。     

我国优秀男子散打运动员身体素质发展现状研究

散打是一项技击对抗性项目,以其精彩激烈深受人们的喜爱。然而散打要发展就必须走出去,而散打走出去的过程就是打出去的过程。然而在这个过程中,我们却遇到了巨大挑战,优势正在缩小,甚至大级别已经无任何优势可言。究其原因,并不在于技术,而主要在于身体素质方面。综观近年来的     

我国优秀男子龙舟运动员身体素质评价模型的研究

运用文献资料法,数理统计法,专家访谈法等多种研究方法,对2009年全国龙舟锦标赛、中华龙舟大赛总决赛、2010年亚运会全国选拔赛中各单项前六名的30支优秀男子龙舟队伍的运动员身体素质指标进行研究,通过研究分析,确立我国优秀男子龙舟运动员身体素质的评价模型。结果表明:1)我国优秀男子龙舟运动员的身体素质主要由力量、耐力、柔韧、速度、灵敏5个因子构成,其中力量因子和耐力因子的载荷贡献率较大。2)我国优秀男子龙舟运动员的身体素质特征表现为:力量较大,速度快,耐力突出,反应灵敏,柔韧性很好等特点。3)根据各素质指标测得数据统计分析,按其的权重比例构建评价体系模型,为我国优秀男子龙舟运动员的科学选材和训练提供重要的参考依据。     

Effects of recombinant human erythropoietin injections on physical self in endurance athletes

This study examined the time course of mean self-esteem and physical self scores in three groups: male endurance athletes treated with recombinant human erythropoietin (rHuEPO group, n = 6), a placebo group (n = 5) injected with a sodium chloride solution and a control group who did not receive any injection (n = 6). Each participant completed the Physical Self Inventory twice a day (between 07.00 and 09.00 h and between 19.00 and 21.00 h). Using a 10 cm visual analog scale, the participants assessed global self-esteem, physical self-worth and the sub-domains of physical condition, sport competence, attractive body and physical strength (Fox & Corbin, 1989). This was conducted over three consecutive periods: in the 2 weeks before the course of injections, during the 6 weeks of injections and for 4 weeks after the injections. Aerobic capacity was assessed before and after 4 weeks of treatment. The results showed a significant increase in aerobic physical fitness in the rHuEPO group and a significant increase in perceived physical condition and physical strength scores at the end of treatment. The main psychological result was that endurance athletes were highly sensitive to the effects of rHuEPO on physical fitness. The perception of increased physical condition may lead to a stronger commitment to training. The rHuEPO injections presented a dangerous hedonic effect linked to endurance training. These results confirm the need to tackle rHuEPO abuse at any time during the training season.     

Effects of external loading on power output in a squat jump on a force platform: a comparison between strength and power athletes and sedentary individuals

The aim of this study was to determine the effects of external loading on power output during a squat jump on a force platform in athletes specializing in strength and power events (6 elite weight-lifters and 16 volleyball players) and in 20 sedentary individuals. Instantaneous power was computed from time-force curves during vertical jumps with and without an external load (0, 5 or 10 kg worn in a special vest). The jumps were performed from a squat position, without lower limb counter-movement or an arm swing. Peak instantaneous power corresponded to the highest value of instantaneous power during jumping. Average power throughout the push phase of the jump was also calculated. A two-way analysis of variance showed significant interactions between the load and group effects for peak instantaneous power (P< 0.01) and average power (P< 0.001). Peak instantaneous power decreased significantly in sedentary individuals when moderate external loads were added. The peak instantaneous power at 0 kg was greater than that at 5 and 10 kg in the sedentary individuals. In contrast, peak instantaneous power was independent of load in the strength and power athletes. Mean power at 0 kg was significantly lower than at 5 kg in the athletes; at 0 kg it was significantly higher than at 10 kg in the sedentary males and at 5 and 10 kg in the sedentary females. In all groups, the force corresponding to peak instantaneous power increased and the velocity corresponding to peak instantaneous power decreased with external loading. The present results suggest that the effects of external loading on peak instantaneous power are not significant in strength and power athletes provided that the loads do not prevent peak velocity from being higher than the velocity that is optimal for maximal power output.     

Effects of external loading on power output in a squat jump on a force platform: A comparison between strength and power athletes and sedentary individuals

The aim of this study was to determine the effects of external loading on power output during a squat jump on a force platform in athletes specializing in strength and power events (6 elite weight-lifters and 16 volleyball players) and in 20 sedentary individuals. Instantaneous power was computed from time-force curves during vertical jumps with and without an external load (0, 5 or 10 kg worn in a special vest). The jumps were performed from a squat position, without lower limb counter-movement or an arm swing. Peak instantaneous power corresponded to the highest value of instantaneous power during jumping. Average power throughout the push phase of the jump was also calculated. A two‐way analysis of variance showed significant interactions between the load and group effects for peak instantaneous power ( P < 0.01) and average power ( P < 0.001). Peak instantaneous power decreased significantly in sedentary individuals when moderate external loads were added. The peak instantaneous power at 0 kg was greater than that at 5 and 10 kg in the sedentary individuals. In contrast, peak instantaneous power was independent of load in the strength and power athletes. Mean power at 0 kg was significantly lower than at 5 kg in the athletes; at 0 kg it was significantly higher than at 10 kg in the sedentary males and at 5 and 10 kg in the sedentary females. In all groups, the force corresponding to peak instantaneous power increased and the velocity corresponding to peak instantaneous power decreased with external loading. The present results suggest that the effects of external loading on peak instantaneous power are not significant in strength and power athletes provided that the loads do not prevent peak velocity from being higher than the velocity that is optimal for maximal power output.     

Validation of two accelerometers to determine mechanical loading of physical activities in children

The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4–15.7) years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw acceleration signals at 100 Hz. Participants completed different tasks (walking, jogging, running, landings from boxes of different height, rope skipping, dancing) on a force plate. GRF was collected for one step per trial (10 trials) for ambulatory movements and for all landings (10 trials), rope skips and dance procedures. Accelerometer outputs as peak loading (g) per activity were averaged. ANOVA, correlation analyses and Bland–Altman plots were computed to determine validity of accelerometers using GRF. There was a main effect of task with increasing acceleration values in tasks with increasing locomotion speed and landing height (P < 0.001). Data from ACT and GEN correlated with GRF (r = 0.90 and 0.89, respectively) and between each other (r = 0.98), but both accelerometers consistently overestimated GRF. The new generation of accelerometer models that allow raw signal detection are reasonably accurate to measure impact loading of bone in children, although they systematically overestimate GRF.     

逐级递增负荷力竭性运动对短跑运动员自由基代谢的影响

研究了逐级递增负荷力竭性运动对短跑运动员自由基代谢的影响。结果表明：逐级递增负荷力竭性运动使机体脂质过氧化反应明显加强，自由基防御体系协同完整的抗氧化能力明显降低，但运动对不同的抗氧化剂影响是不同的；尿液MDA含量、尿液T-SOD活力是反映自由基代谢状态的灵敏指标。     

我国优秀大级别男子散打运动员专项身体素质评价标准研究

以备战2008年北京奥运会国家散打队大级别男子散打运动员为研究对象,采用文献资料等方法对其专项身体素质的16项指标进行了测量,并运用SPSS10.0软件的主成分分析等多元统计分析方法对测量结果进行处理.结果表明:专项身体素质主要是由拳法耐力因子、腿法耐力因子等七方面组成;认定10s直拳、10s鞭腿等8项指标是反映其竞技水平的主要专项身体素质指标,并分析了专项身体素质与运动成绩的关系,制定了专项身体素质单项和综合发展水平评价标准以及专项身体素质发展均衡度的评价标准.经检验,所制定的各项评价标准效果较好,可为专项身体素质训练的科学化以及选材提供较为科学的参考依据.     

运动对青年女性跟骨骨密度及性激素的影响

对60名武汉体育学院健康女性研究生进行了测试,探索运动对青年女性跟骨骨密度及性激素的影响。结果发现:体育专业组的女生跟骨BUA、SOS、STI等指标均高于体育锻炼组,RRF低于体育锻炼组;体育锻炼组的BUA、SOS、STI等指标均高于对照组,而RRF低于对照组。体育专业组E2显著高于对照组,体育锻炼组E2与对照组之间无显著差异;3组之间的t值没有显著性差异。可见,长期适宜的运动对提高青年女性跟骨的BUA、SOS、STI,降低RRF都具有显著性影响。E2、T对女性跟骨骨密度具有影响趋势,但都没有统计学意义。     

Effects of tapering on physical match activities in professional soccer players

ABSTRACT

This study aimed to examine: (i) the effect of decreasing training load (TL) during taper weeks on physical match activities in professional soccer players, and (ii) to disclose the relationship between weekly TL and physical match activities. Rating of perceived exertion was collected after each training session and match to quantify the TL in 19 professional players over 17 standard and 7 taper weeks during the season. Physical match activities were quantified by a computerised match analysis system and compared between standard training and taper weeks. Compared to standard weeks, the duration and frequency of training sessions during the taper weeks decreased (?21.7% and ?18.8%, respectively; P < 0.01) with no change in intensity (?4.8%; P = 0.09). Consequently, the weekly TL decreased during the taper weeks (?25.5%; P < 0.01). Increases in distance covered by intense running (+15.1%; P < 0.05), high-intensity running (HIR) (+15.7%; P < 0.01), number of sprints (+17.8%; P < 0.05) and number of high-speed runs (+15.7%; P < 0.05) were observed during the seven matches played after the taper weeks. High relationships were observed between TL and HIR distance covered, number of HIR and number of sprints (r = ?0.53; r = ?0.55; r = ?0.65, respectively; P < 0.01). Decreasing TL during taper weeks by reducing training duration and frequency but maintaining intensity was associated with an increase in physical activities during matches. However, it needs to be determined whether tapering or other match factors led to the changes in match activity.     

The impact of different types of physical activity on total and regional bone mineral density in young Brazilian athletes

Bone turnover is affected by exercise throughout the lifespan, especially during childhood and adolescence. The objective of this study was to investigate the impact of different sports on total and regional bone mineral density in male Brazilian adolescent athletes. Forty-six adolescents aged 10-18 years participated in the study: 12 swimmers, 10 tennis players, 10 soccer players, and 14 sedentary individuals. The athletes had engaged in physical activities for more than 10 h per week in the previous 6 months. Bone mineral density of the lumbar spine (L1-L4), left proximal femur region, and whole body was evaluated by dual-energy X-ray absorptiometry. Results showed higher mean values in the proximal femur region of tennis and soccer players (1.02 ± 0.18; 0.96 ± 0.16, respectively) than swimmers and controls (0.91 ± 0.14 and 0.87 ± 0.06, respectively) (P < 0.05). In relation to the impact of sporting activities based on bone age determination, we observed significant differences in bone mineral density at all evaluated sites at the end of puberty (16-18 years) compared with 10-12 years, with increases of 78% in the lumbar spine, 47% in the proximal femur, and 38% in the whole body.     

体育选项课程对大学男生体质健康影响的研究

运用实验、测量和数理统计等方法,分别对体育舞蹈、篮球、足球、乒乓球、武术体育选项课程对促进大学男生的体质健康变化进行研究。结果显示：体育选项课程对促进大学生男生身体素质均具有显著性差异,篮球比乒乓球课程更能发展学生爆发力素质;武术比体育舞蹈课程更能发展学生力量素质;体育舞蹈、足球课程比武术课程更能发展学生呼吸系统的机能;对其他素质和机能、形态的促进与发展无显著性差异。建议进一步探究体育选项课程对学生体质特征具有显著性差异的的原因和内在规律,以期为体育选项课程的理论与实践提供依据。     

体育锻炼对老年人骨密度的影响

通过对华东地区部分老年人跟骨骨密度(BMD)测量,探讨老年人衰老过程中跟骨BMD的性别差异以及体育锻炼对老年人跟骨BMD的影响.结果显示,老年人跟骨BMD存在着性别的高度显著性差异,老年男性跟骨BMD明显高于老年女性.老年男性常锻炼组的BMD显著高于不常锻炼组.结果提示,经常参加体育锻炼可以增加老年男性骨密度,从而减少骨质疏松症的发生.     

太极拳锻炼对原发性骨质疏松症患者骨密度及骨代谢的影响

观察太极拳锻炼对原发性骨质疏松症患者骨密度及骨代谢的影响。将原发性骨质疏松症患者40例随机分成对照组和太极拳组,实验前后对两组患者骨密度值、血清骨钙素（BGP）、碱性磷酸酶（ALP）以及骨痛的变化情况进行比较分析,实验结果发现：实验后太极拳组与对照组的腰椎骨、股骨、颈骨密度差异呈显著性;BGP、ALP的比较差异分别呈显著性;骨痛积分两组间比较差异具有显著性。结果说明,太极拳锻炼是防治原发性骨质疏松症的有效方法,值得推广应用。     

我国男子赛艇运动员的身体形态指标研究

运动员专项身体形态指标历来是选材和训练监控的重要指标内容,在全面测试了参加我国第10届全国运动会的137名男赛艇运动员的身体形态指标的基础上,对所测数据进行了主成分分析与因子分析,找出了影响赛艇运动员最重要的专项身体形态因素——粗壮程度及其代表指标,为赛艇专项运动选材和训练监控提供参考。     

跳跃训练对模拟失重大鼠骨密度和骨代谢指标的影响

目的:通过尾部悬吊模拟后肢失重模型,研究在尾部悬吊期间进行跳跃训练对大鼠骨密度和骨代谢的影响,为宇航员骨质流失的防治提供方法参考.方法:7周龄Wistar雄性大鼠24只,随机分为3组,每组8只,即正常对照组(CON),模拟失重组(SUS)和模拟失重+跳跃训练组(JUM).通过后肢悬吊的方法制备大鼠后肢模拟失重模型,悬吊和跳跃周期均为3周,3周的干预结束后,测试各组大鼠右侧股骨骨密度和血清骨代谢指标血钙、碱性磷酸酶、骨钙素和抗酒石酸酸性磷酸酶5b.结果:与CON组大鼠相比,SUS组大鼠骨吸收指标血钙(Ca2+)和抗酒石酸酸性磷酸酶5b (TRACP5b)水平均显著增加(P＜0.01),骨形成指标血清碱性磷酸酶(ALP)和骨钙素(BGP)水平显著降低(P＜0.05),骨密度显著下降(P＜0.01);与SUS组大鼠相比,JUM组大鼠骨吸收指标血钙(Ca2+)和抗酒石酸酸性磷酸酶5b (TRACP5b)水平显著降低,骨形成指标血清碱性磷酸酶(ALP)和骨钙素(BGP)水平显著增加,骨密度显著升高(P＜0.01).结论:尾部悬吊模拟后肢失重可导致大鼠骨吸收作用增强,骨形成作用降低,骨密度下降.而在模拟失重期间进行跳跃训练可有效抑制大鼠骨吸收和增强其骨形成,从而有效抑制尾部悬吊大鼠骨密度的下降.