青少儿最大无氧功能适宜负荷及其影响因素的探讨

本文用改良的WAnT无氧功测试方法,测试了136名13-18岁青少年男子的无氧功和形态指标,得到功率与负荷之间呈抛物线关系,其中抛物线最高点所对应的横坐标值为适宜负荷。每一个体适宜负荷值与形态指标的多元逐步回归分析得出:适宜负荷与体重、大腿围度相关最密。     

我国优秀击剑运动员有氧及无氧能力测试与分析

在北京奥运会集训期间,对国家队3个剑种男女重点运动员最大摄氧量和WAnT无氧功率进行测定.结果显示:花剑运动员最大摄氧量最高,女佩运动员最低.WAnT测试,峰功率男佩运动员显著高于男重和男花运动员;平均功率男花和男佩运动员显著高于男重运动员;功率衰减率从大到小依次为男佩运动员、男重运动员和男花运动员.女运动员中,峰功率无显著性差别,平均功率女花运动员显著高于其他两组,功率衰减率女佩运动员最高.WAnT测试后血乳酸峰值在同性别组间无差异,峰值出现时间为测试后8-10 min.提示:不同剑种运动员无氧及有氧能力不同,男运动员间差异尤为突出.     

四川省幼儿体质2014年与2000年纵向比较分析

目的:分析比较2014牟和2000年四川省3-6岁幼儿体质数据,为增进幼儿体质健康提供参考依据.方法:采用2014年和2000年四川省国民体质监测幼儿部分测试数据,分析年代纵向差异与趋势.结果:1、2014年幼儿身高、坐高、体重、胸围等指标平均数高于2000年,差异具有统计学意义(p＜0.01);2、与2000年监测结果比较,除网球掷远外,其他各项身体素质2014年均有增长(p＜0.01);3、幼儿体质综合评价与2000年比较,2014年合格率提高11.6％ (p＜0.01),优秀率下降1.7％.结论:从2000年到2014年,四川省3-6岁幼儿身体形态和身体素质全面增长,合格率明显提高.     

补充辅酶Q10及递增负荷跑台运动训练对大鼠心肌和脑线粒体电子传递链酶复合体活性的影响

目的:观察递增负荷跑台运动训练及补充CoQ10对力竭运动大鼠心肌和脑线粒体呼吸链复合体Ⅰ、Ⅱ和Ⅲ活性的影响.方法:36只健康雄性Wister大鼠随机分为安静对照组、补充CoQ10组、训练组和训练结合补充CoQ10组.差速离心提取心肌和脑线粒体;分光光度法测定线粒体呼吸链酶复合体(Ⅰ～Ⅲ)活性.结果:1)安静状态下补充CoQ10 7周,与安静对照组相比较,力竭运动后即刻心肌线粒体呼吸链CⅡ活性增强(P＜0.01),CⅠ和CⅢ活性减弱(P＜0.01);脑线粒体呼吸链CⅡ活性显著性降低(P＜0.01).2)递增负荷运动训练7周,与安静对照组相比较,力竭运动后即刻心肌线粒体呼吸链CⅠ和CⅡ活性减弱(P＜0.01)、CⅢ活性增强(P＜0.05).3)递增负荷训练结合补充CoQ10 7周,与安静对照组相比较,力竭运动后即刻心肌线粒体呼吸链CⅠ和CⅡ活性减弱(P＜0.01),脑线粒体呼吸链CⅡ活性显著性下降(P＜0.01).4)递增负荷训练结合补充CoQ10与单纯补充CoQ10组相比,力竭运动后即刻心肌线粒体呼吸链CⅡ活性减弱(P＜0.01)、CⅢ活性增强(P＜0.01);脑线粒体呼吸链CⅡ活性显著性下降(P＜0.01).5)递增负荷训练结合补充CoQ10与单纯运动训练组相比,力竭运动后即刻心肌线粒体呼吸链CⅡ和CⅢ活性减弱(P＜0.01);脑线粒体呼吸链CⅡ活性显著性下降(P＜0.01).结论:外源性补充CoQ10对大鼠体重增长无负面影响,运动训练可以降低大鼠体重增长幅度.单纯补充CoQ10可增强力竭运动后即刻大鼠心肌线粒体呼吸链CⅡ活性;降低脑线粒体呼吸链CⅡ活性;对力竭运动时间无影响.递增负荷训练可增强力竭运动后即刻大鼠心肌线粒体呼吸链CⅢ活性;对脑线粒体呼吸链CⅠ、CⅡ和CⅢ活性无明显影响;运动能力得到提高.递增负荷训练结合补充CoQ10可维持力竭运动后即刻大鼠心肌线粒体呼吸链CⅢ活性不降低;脑线粒体呼吸链CⅡ活性显著性下降、CⅠ和CⅢ活性无显著性变化;运动能力得到提高;运动训练与补充CoQ10对改善心肌和脑线粒体呼吸链cⅠ、CⅡ和CⅢ活性及运动能力方面无协同作用.训练组及训练结合补充CoQ10组大鼠力竭运动时间的延长可能还与体重增长较慢及其他机制有关.     

不同训练方法对普通高校健美操运动员身体形态的影响

目的:探讨不同训练手段对普通高校健美操运动员身体形态的影响.方法:选取邵阳学院体育系健美操专选班大学生36人,随机分为CMJ、DJ、SE、SC4组,每组9人.观察训练14周后受试者的体重、腰围、大腿围度和小腿国度的变化.结果:14周训练后,(1)CMJ和DJ组的体重没有显著变化(P＞0.05),而SE和SC组的体重显著增加(P＜0.05);(2)各组腰围显著减小(P＜0.01),其中以CMJ、DJ组的效果最好(P＜0.01);(3)SC组大腿国度明显增加(P＜0.05),而其他3组没有显著性变化(P＞0.05);(4) DJ组的小腿国度显著减小(P＜0.05),其他3组没有显著性变化(P＜0.05).结论:不同训练手段可以明显影响普通高校健美操运动员的身体形态.因此,可以根据运动员不同个体形态的需要,选择合适的训练方法.     

力竭性游泳运动对大鼠肾脏线粒体功能损伤的影响

研究目的为了研究运动对肾脏损伤的发生机理,探讨力竭性运动引起的氧化应激对肾脏线粒体功能的影响.研究方法30只SD大鼠随机分成4组,即对照组、运动即刻组、运动后1 h组和运动后24 h组,采用分光光度法、化学发光法和原子吸收光谱法测定不同时相肾脏线粒体MDA、ATP合成能力和总钙的变化.研究结果运动后各项指标与对照组比较,MDA含量在运动后即刻显著升高(p＜0.05),1 h和24 h后极显著升高(p＜0.01);运动后即刻组,1 h和24 h组肾线粒体ATP合成能力极显著低于对照组(p＜0.01),24 h后基本恢复正常;肾脏线粒体总钙在运动后1 h和24 h后显著降低(p＜0.01),运动后24 h后仍未恢复正常.结论大鼠力竭性游泳可导致肾脏线粒体脂质过氧化水平提高,ATP合成能力下降,线粒体钙稳态失调,而线粒体钙聚积可导致线粒体氧化磷酸化解偶联和肾功能异常,这些可能是运动性疲劳发生的重要原因之一.     

低氧训练对大鼠骨骼肌HIF-1mRNA及铁转运蛋白表达的影响

目的:探讨低氧、低氧训练对大鼠骨骼肌铁代谢的影响.方法:32只雄性SD大鼠随机均分为常氧安静组(NC)、常氧运动组(NE)、低氧安静组(HC)和低氧运动组(HE).跑台训练(21～25 m/min,每周增1 m/min,1 h/天,6天/周),HC组进行低氧暴露(13.6％氧,8h/天,6天/周).原子吸收法、RT-PCR、Western blot检测结果.结果:与NC组比,各组大鼠腓肠肌总铁含量升高(P＜0.05,P＜0.01);HE组高于NE、HC组(P＜0.05).HC和HE组骨骼肌HIF-1 mRNA表达高于NC、NE组(P＜0.01).与NC组相比,NE、HC、HE组骨骼肌铁吸收蛋白升高(P＜0.05,P＜0.01);NE、HC组铁释放蛋白下降(P＜0.05,P＜0.01),HE组升高(P＜0.01);HE组各蛋白表达均高于NE和HC组(P＜0.01).结论:大鼠适度运动和单纯低氧均能增加骨骼肌铁贮存,而低氧训练能促进骨骼肌铁吸收和铁释放.     

模拟“低住高练（LoHi）”对游泳运动员运动能力的影响

目的探讨LoHi训练法对运动员运动能力的影响机制,为LoHi训练法在运动实践中的应用提供理论和实践依据.方法对15名优秀游泳运动员进行2周的LoHi训练,分别于训练前后进行气体代谢、力竭性递增负荷运动能力测试;在训练的整个过程中进行5次专项有氧能力的测试.结果2周LoHi训练后,①男运动员VO2max、VO2max/kg、Vemax和O2-plusemax显著提高(P＜0.05),女运动员无显著性变化(P＞0.05);②力竭性递增负荷运动后,男女运动员运动后的Bla均非常显著的下降(P＜0.01～0.001),男女间无性别差异(P＞0.05);同时运动后Bla的下降率表现为逐渐升高的趋势;③力竭性递增负荷运动中,男运动员Wmax提高了12.7%(P＜0.01),女运动员则提高了6.12%(P＞0.05); Tmax男子提高17.7%(P＜0.05),女子提高7.44%(P＜0.05);④男运动员在2周LoHi训练过程中运动成绩呈升高趋势,Bla呈逐渐下降趋势,训练后7d运动成绩最好,Bla却下降51.9%(P＜0.01);女运动员在训练过程中运动成绩和Bla均呈下降趋势,训练后7d运动成绩最高,18d下降,但Bla均明显低于训练前(P＜0.01).结论两周LoHi训练提高了运动员对负荷的适应能力,特别使运动员的一般有氧能力和专项有氧能力得到明显改善;同时,女运动员对缺氧的适应能力明显低于男子,表现出明显的性别差异.     

65%～75%最大强度的耐力运动对老龄小鼠骨骼肌线粒体氧化应激与膜电位的影响

目的:探讨线粒体氧化应激与增龄性骨骼肌流失之间的关系,进一步揭示耐力运动对增龄性骨骼肌流失的影响机制.方法:选用40只ICR小鼠建立2、4、6、8月龄增龄性骨骼肌流失模型;另选用40只ICR小鼠分为4组:青年对照组(YC)、青年运动组(YR)、老龄对照组(AC)和老龄运动组(AR);每组10只.对不同月龄小鼠采用递增负荷进行运动能力测试,YR、AR组小鼠按最大负荷的65%～75%进行耐力训练,每天训练1 h,持续4周.取腓肠肌、股四头肌称重,荧光探针法检测腓肠肌线粒体活性氧(ROS)产率与膜电位,ELISA法检测腓肠肌8-羟基-脱氧鸟苷(8-OH-dG)含量.结果:1)4月龄组腓肠肌、左右股四头肌湿重显著高于2、6、8月龄组(P＜0.05);但耐力运动对AR、YR组小鼠骨骼肌湿重均无显著影响.2)8月龄组线粒体ROS产率显著高于2、4、6月龄组(P＜0.01),6、8月龄组8-OH-dG含量显著高于2月龄、4月龄组(P＜0.05).AR组8-OH-dG含量显著高于AC组(P＜0.05).3)与2月龄组比较,4、6、8月龄组线粒体膜电位显著下降(P＜0.01);与4、6月龄组比较,8月龄组线粒体膜电位进一步显著下降(P＜0.01).AR组线粒体膜电位显著高于AC组(P＜0.05).结论:在增龄性骨骼肌流失的不同时期,先后出现线粒体膜电位下降、DNA氧化损伤加剧、ROS产率增加.65%～75%最大强度的耐力运动提高了老龄小鼠骨骼肌的线粒体膜电位,表明耐力运动对老龄小鼠维持线粒体功能、防止肌细胞凋亡有重要意义,但也可能加剧DNA氧化损伤.建议老年人有必要从事耐力运动但不宜采用过高的运动强度.     

过度运动激活中性粒细胞产生的活性氧对淋巴细胞DNA损伤及干预研究

目的:探讨过度运动激活中性粒细胞NADPH氧化酶介导产生的活性氧(ROS)对淋巴细胞DNA损伤的影响及实施二联苯碘(DPI)干预作用.方法:30只雄性Vistar大鼠随机分为3组,安静组(C,n=10)、过度训练组(E,n=10)和DPI干预组(D,n=10),E组和D组进行递增负荷跑台训练11周,末次训练结束后在36～40 h内各组随机取8只眼眶静脉采血.应用ELISA方法检测血浆细胞因子水平及血液中脂质过氧化水平;提取白细胞用AnnexinV/PI双染色法流式测定中性粒细胞凋亡与坏死程度;免疫细胞化学的激光共聚焦法测定NADPH氧化酶关键亚基的gp91 phox与p47phox的共定位;单细胞凝胶电泳测定淋巴细胞的DNA损伤程度.结果:1)与C组比较.E组血浆IL-1b显著性升高,IL-8、TNF-α显著升高(分别为P＜0.01和P＜0.05),MCP-1与CINC显著性下降(P＜0.05);而D组血浆IL-1b、MCP-1显著下降(P＜0.05),IL-8、TNF-α显著性升高(P＜0.05);E组和D组大鼠血浆慨、MPO水平均上升(分别为P＜0.01和P＜0.05);2)与C组相比,E组、D组中性粒细胞性凋亡的百分比均显著上升(P＜0.01),但中性粒细胞的死亡数E组增加(P＜0.05)而D组无显著变化;3)与C组比较,E组出现DNA损伤的彗星细胞数非常显著性升高(P＜0.01),且彗星细胞的宽度和尾长的变化均达到显著性水平,而D组的变化均未达到显著性水平;4)中性粒细胞的共聚焦染色定位显示:与安静组对照比较,E组出现了NADPH氧化酶关键亚基的gp91phox与p47phox的共定位.结论:1)过度运动可引起外周血炎性因子和趋化分子分泌的增加,从而有可能诱发组织炎症的发生和而调节T淋巴细胞的分化;2)过度运动可激活外周血中性粒细胞的NADPH氧化酶介导产生过多的ROS使血液的脂质过氧化水平提高;3)由此途径产生的ROS的增多和血液过氧化水平的提高可能引起中性粒细胞本身的凋亡甚至死亡和淋巴细胞的DNA损伤:4)由此途径产生的ROS的增多、吞噬细胞及淋巴细胞的过氧化损伤、炎性因子及免疫调节因子的变化等多因素可调节细胞免疫,是过度运动引起的运动型免疫抑制的可能因素.     

The impact of load on lower body performance variables during the hang power clean

This study examined the impact of load on lower body performance variables during the hang power clean. Fourteen men performed the hang power clean at loads of 30%, 45%, 65%, and 80% 1RM. Peak force, velocity, power, force at peak power, velocity at peak power, and rate of force development were compared at each load. The greatest peak force occurred at 80% 1RM. Peak force at 30% 1RM was statistically lower than peak force at 45% (p = 0.022), 65% (p = 0.010), and 80% 1RM (p = 0.018). Force at peak power at 65% and 80% 1RM was statistically greater than force at peak power at 30% (p < 0.01) and 45% 1RM (p < 0.01). The greatest rate of force development occurred at 30% 1RM, but was not statistically different from the rate of force development at 45%, 65%, and 80% 1RM. The rate of force development at 65% 1RM was statistically greater than the rate of force development at 80% 1RM (p = 0.035). No other statistical differences existed in any variable existed. Changes in load affected the peak force, force at peak power, and rate of force development, but not the peak velocity, power, or velocity at peak power.     

Allometric scaling of Wingate anaerobic powertest scores in women

In this study, we developed allometric exponents for scaling Wingate anaerobic test (WAnT) power data that are effective in controlling for body mass (BM) and lean body mass (LBM) and established a normative WAnT data set for college-age women. One hundred women completed a standard WAnT Allometric exponents and percentile ranks for peak (PP) and mean power (MP) were established. Allometric exponents were applied to WAnT scores for an independent sample (n=31) to assess external validity. PP and MP were 477.0 W (SD = 80.0) and 372.6 W (SD = 61.5), respectively. Allometrice exponents for PP and MP scaled for BM were b = 0.92 and b = 0.76, respectively, and for LBM they were b = 0.93 and b = 0.91, respectively. In the independent sample, these exponents produced correlations between allometrically scaled PP and MP and BM of r = -.02 and r = .02, respectively. Correlations between allometrically scaled PP and MP and LBM were r = .004 and r = -.02, respectively. The allometric exponents were effective in partialing out the effect of BM for PP and MP and demonstrated acceptable levels of external validity when applied to an independent sample. The allometric exponents and normative values provide a useful tool for comparing WAnT scores in college-age women without the confounding effects of BM or LBM.     

Redistributing load using wearable resistance during power clean training improves athletic performance

A popular method to improve athletic performance and lower body power is to train with wearable resistance (WR), for example, weighted vests. However, it is currently unknown what training effect this loading method has on full-body explosive movements such as the power clean. The purpose of this study was to determine what effects WR equivalent to 12% body mass (BM) had on the power clean and countermovement jump (CMJ) performance. Sixteen male subjects (age: 23.2?±?2.7 years; BM: 90.5?±?10.3?kg) were randomly assigned to five weeks of traditional (TR) power clean training or training with 12% BM redistributed from the bar to the body using WR. Variables of interest included pre and post CMJ height, power clean one repetition maximum (1RM), peak ground reaction force, power output (PO), and several bar path kinematic variables across loads at 50%, 70%, and 90% of 1RM. The main findings were that WR training: (1) increased CMJ height (8.7%; ES?=?0.53) and 1RM power clean (4.2%; ES?=?0.2) as compared to the TR group (CMJ height?=??1.4%; 1RM power clean?=?1.8%); (2) increased PO across all 1RM loads (ES?=?0.33–0.62); (3) increased barbell velocity at 90% 1RM (3.5%; ES?=?0.74) as compared to the TR group (?4.3%); and (4) several bar path kinematic variables improved at 70% and 90% 1RM loads. WR power clean training with 12% BM can positively influence power clean ability and CMJ performance, as well as improve technique factors.     

W5″ Test: A simple method for measuring mean power output in the bench press exercise

The aims of the present study were to assess the validity and reliability of a novel simple test [Five Seconds Power Test (W5″ Test)] for estimating the mean power output during the bench press exercise at different loads, and its sensitivity to detect training-induced changes. Thirty trained young men completed as many repetitions as possible in a time of ≈5?s at 25%, 45%, 65% and 85% of one-repetition maximum (1RM) in two test sessions separated by four days. The number of repetitions, linear displacement of the bar and time needed to complete the test were recorded by two independent testers, and a linear encoder was used as the criterion measure. For each load, the mean power output was calculated in the W5″ Test as mechanical work per time unit and compared with that obtained from the linear encoder. Subsequently, 20 additional subjects (10 training group vs. 10 control group) were assessed before and after completing a seven-week training programme designed to improve maximal power. Results showed that both assessment methods correlated highly in estimating mean power output at different loads (r range: 0.86–0.94; p?R²: 0.78). Good to excellent intra-tester (intraclass correlation coefficient (ICC) range: 0.81–0.97) and excellent inter-tester (ICC range: 0.96–0.99; coefficient of variation range: 2.4–4.1%) reliability was found for all loads. The W5″ Test was shown to be a valid, reliable and sensitive method for measuring mean power output during the bench press exercise in subjects who have previous resistance training experience.     

Description of a Low Cost Microcomputer System Interfaced to Exercise Stress Testing Equipment

Abstract

In recent years the classic Margaria step-test for anaerobic power has been largely replaced by bicycle ergometer tests, the most popular of these being the Wingate Anaerobic Test (WAnT). The purpose of this study was to examine the relationship between the WAnT and sprint-run times and to determine the influence of age and weight on the WAnT scores. The 56 male volunteers (age 10–15 years) recruited from a track club and junior high school represented a wide range of athletic abilities. Subjects were tested for anaerobic power (5 sec output) and capacity (30 sec output) using the Wingate test procedures. Wingate scores for anaerobic power and capacity were only moderately correlated with 50 yd dash times (r = ?.53 and ?.53) and with the 600 yd run (r = ?.26 and ?.29). Partial correlations between these variables were lower when age adjusted and higher when adjusted for body weight. Results of this study indicate that the Wingate anaerobic test is only a moderate predictor of dash or run times, but becomes a stronger predictor when WAnT scores are adjusted for body weight. The high correlation of the WAnT with body weight must be taken into account when comparing the anaerobic capacity of individuals. The standing long jump would be the preferred field test of sprint-related ability because of its simplicity, but the Wingate lest has the advantage of providing a quantitative measurement of anaerobic fitness.     

8周游泳运动对2型糖尿病大鼠海马胰岛素抵抗的影响及机制

目的探讨糖尿病大鼠海马胰岛素抵抗的发生发展及在运动干预下糖尿病海马胰岛素抵抗与半乳糖苷凝集素3以及脂联素/AMPK/GLUT4信号通路之间的关系。方法高脂饮食联合腹腔注射低剂量STZ诱导的2型糖尿病大鼠建模成功后随机分为糖尿病对照组(DM组)和糖尿病运动组(DME组)两组。DM组大鼠不运动,DME组进行8周无负重游泳训练,6次/周。大鼠于末次训练后禁食12h,次日以2.5ml/kg的剂量,腹腔注射10%的水合氯醛麻醉,随后胸主动脉取血后保存于-20℃,以备待测,取海马组织投入液氮,-80℃冰箱保存。结果1)与NC组相比,DM组大鼠血清FBG、HOMA-IR的含量显著性增加(p<0.01),而大鼠血清INS含量减少,但无显著性差异(p>0.05);与DM组相比,DME组大鼠血清FBG、HOMA-IR的含量显著性减少(p<0.05),而大鼠血清INS含量减少,但无显著性差异(p>0.05);2)Real-Time PCR结果显示:与NC组相比,DM组大鼠GLUT4、PI3K及Adiponectin(脂联素)mRNA表达水平显著降低(p<0.01),Galectin-3、IRS-1mRNA表达水平显著升高(p<0.05,p<0.01),尽管AMPK、AKtmRNA表达水平无显著性变化,但存在有明显的下降趋势;与DM组相比,DME组大鼠海马组织的Galectin-3mRNA表达水平显著降低(p<0.05),PI3K、GLUT4及Adiponectin mRNA表达水平呈显著增加(p<0.01),AMPK、IRS-1及AKt mRNA表达水平无显著性变化,但仍存在改善趋势。结论1)2型糖尿病将导致病理性中枢胰岛素抵抗,同时8周有氧运动能够有效改善2型糖尿病海马胰岛素抵抗;2)8周有氧运动可能通过降低海马组织Gal-3水平以及提高脂联素/AMPK/GLUT4信号通路表达,从而达到改善2型糖尿病海马胰岛素抵抗,同时Gal-3以及脂联素/AMPK/GLUT4信号通路异常可能也是2型糖尿病病理性引发中枢胰岛素抵抗的机制之一。     

Comparison of individual and group-based load-velocity profiling as a means to dictate training load over a 6-week strength and power intervention

ABSTRACT

This study compared the effects of dictating load using individual (ILVP) or group (GLVP) load-velocity profiles on lower-body strength and power. Nineteen trained males (23.6 ± 3.7 years) completed a back squat one-repetition maximum (1-RM), load-velocity profiling (LVP), and countermovement (CMJ), static-squat (SSJ) and standing-broad (SBJ) jump tests before and after 6 weeks of resistance training. Participants were randomly assigned to an ILVP, or GLVP intervention with intra-session load dictated through real-time velocity monitoring and prediction of current relative performance using either the participant’s LVP (ILVP) or a LVP based on all participant data (GLVP). Training resulted in significant increases in back squat 1-RM for the ILVP and GLVP group (p < 0.01; 9.7% and 7.2%, respectively), with no group-by-time interaction identified between training groups (p = 0.06). All jump performance significantly increased for the ILVP group (p < 0.01; CMJ: 6.6%; SSJ: 4.6%; SBJ: 6.7%), with only CMJ and SSJ improving for the GLVP group (p < 0.05; 4.3%). Despite no significant group-by-time interaction across all variables, the ILVP intervention induced a greater magnitude of adaptation when compared to a GLVP approach. Additionally, an individualised approach may lead to greater positive transfer to power-based movements, specifically vertical and horizontal jumps.     

Effectiveness and time-course adaptation of resistance training vs. plyometric training in prepubertal soccer players

PurposeThis study aimed to assess the effectiveness and time course for improvements in explosive actions through resistance training (RT) vs. plyometric training (PT) in prepubertal soccer players.MethodsThirty-four male subjects were assigned to: a control group (n = 11); an RT group (5 regular soccer training sessions per week, n = 12); a PT group (3 soccer training sessions and 2 RT sessions per week, n = 11). The outcome measures included tests for the assessment of muscle strength (e.g., 1 repetition maximum half-squat test), jump ability (e.g., countermovement jump, squat jump, standing long jump, and multiple 5 bounds test), linear speed (e.g., 20 m sprint test), and change of direction (e.g., Illinois change of direction test).ResultsThe RTG showed an improvement in the half-squat (Δ = 13.2%; d = 1.3, p < 0.001) and countermovement jump (Δ = 9.4%; d = 2.4, p < 0.001) at Week 4, whereas improvements in the 20-m sprint (Δ = 4.2%; d = 1.1, p < 0.01); change of direction (CoD) (Δ = 3.8%; d = 2.1, p < 0.01); multiple 5 bounds (Δ = 5.1%; d = 1.5, p < 0.05); standing long jump (Δ = 7.2%; d = 1.2, p < 0.01); squat jump (Δ = 19.6%; d = 1.5, p < 0.01); were evident at Week 8. The PTG showed improvements in CoD (Δ = 2.1%; d = 1.3, p < 0.05); standing long jump (Δ = 9.3%; d = 1.1, p < 0.01); countermovement jump (Δ = 16.1%; d = 1.2, p < 0.01); and squat jump (Δ = 16.7%; d = 1.4, p < 0.01); at Week 8 whereas improvements in the 20-m sprint (Δ = 4.1%; d = 1.3, p < 0.01); and multiple 5 bounds (Δ = 7.4%; d = 2.4, p < 0.001); were evident only after Week. The RT and PT groups showed improvements in all sprint, CoD, and jump tests (p < 0.05) and in half-squat performance, for which improvement was only shown within the RTG (p < 0.001).ConclusionRT and PT conducted in combination with regular soccer training are safe and feasible interventions for prepubertal soccer players. In addition, these interventions were shown to be effective training tools to improve explosive actions with different time courses of improvements, which manifested earlier in the RTG than in the PTG. These outcomes may help coaches and fitness trainers set out clear and concise goals of training according to the specific time course of improvement difference between RT and PT on proxies of athletic performance of prepubertal soccer players.     

Power training in elite young soccer players: Effects of using loads above or below the optimum power zone

ABSTRACT

This study aimed to examine the effects of two jump squat (JS) training programs involving different loading ranges in under-20 soccer players during a preseason period. Twenty-three elite young soccer players performed sprint speed (at 5-, 10-, and 20-m), change-of-direction (COD) speed, JS peak-power (PP), and countermovement jump (CMJ) tests pre and post four weeks of training. Athletes were pair-matched in two groups according to their optimum power loads (OPL) as follows: lower than OPL (LOPL; athletes who trained at a load 20% lower than the OPL) and higher than OPL (HOPL; athletes who trained at a load 20% higher than the OPL). Magnitude-based inferences were used to compare pre- and post-training measures. Meaningful increases in the PP JS were observed for both groups. Likely and possible improvements were observed in the 5- and 10-m sprint velocity in the LOPL group. Meanwhile, possible and likely improvements were observed in the CMJ, 5- and 10-m sprint velocity, and COD speed in the HOPL group. Overall, both training schemes induced positive changes in athletic performance. Soccer coaches and sport scientists can implement the JS OPL-based training schemes presented here, either separately or combined, to improve the physical performance of youth soccer players.     

42式太极拳定量负荷对中老年知识分子心肺机能的影响

采用XXG-D型心功能测试仪和F-Ⅱ型肺活量计对72名集美老年大学学员在42式太极拳定量负荷前、后进行心血管机能26个参数、肺活量（VC）测定和5次肺活量试验（FVCT）。结果表明心血管机能可顺应42式太极拳定量负荷，使脉率（PR）、每搏量（SV）、心搏指数（SI）、心输出量（CO）、心脏指数（CI）、左心搏功指数（LVWI）、收缩压（SP）、平均收缩压（MSP）、脉压（PP）和肺活量(VC)适度升高，有显著性差异（P<0.01）；而心肌耗氧量（HOV）、心肌耗氧指数（HOI）增加较少，无统计学意义（P>0.05）；负荷后总外周阻力（TPR）和标准周阻（SPR）下降，有显著性差异（P<0.01），而第1次VC分别与第4次和第5次VC比较增加组的例数较多，与其它各组有显著性差异（P<0.01）。结果表明42式太极拳练习对中老年知识分子属中、小强度的需氧运动项目，其运动量和运动强度适宜，有助于心血管机能、肺通气量的改善和提高。