竞技健美操赛前模拟比赛心率变化分析

以心率指标来反映竞技健美操的运动强度。对参加2008年全国锦标赛的运动员进行赛前模拟比赛的心率测试。结果显示：最大心率百分比都在80％以上。运动中的心率变化跟专业级别没有差异性（P〉0．05）,跟年龄有显著的差异性（P〈0．05）。因此在训练中,训练的方式跟专业级别以及年龄相联系,并可运用心率指标进行监控。     

北京奥运会女子举重比赛成败率与试举方案的统计与分析

通过录像观察法、文献资料法、专家访谈法、数理统计方法对2008年北京奥运会女子举重7个级别的全部赛事成败率进行了技术统计分析,结果表明本届北京奥运会女子举重试举成功率比上届有了大幅度的提高;抓举比赛中的后掉次数比前掉次数高;挺举的上挺失败次数高于下蹲翻失败次数;北京奥运会女子举重的试举方案比上届增多;同时,对各国运动员试举技术失败的原因进行了分析表明,运动员技术发挥不稳定、实力不足和比赛心理素质不好是造成试举失败的主要原因。     

西部地区少数民族学生生长速度的动态变化及其环境影响因素

利用西部地区少数民族学生1985年和2005年体质健康状况调研所获得的数据,对该地区少数民族学生身体形态的生长速度、青春突增期、增长速度高峰及最大年增长值的变化做20年的纵向分析和横向比较,并结合环境因素探讨该地区少数民族学生生长速度变化的特点、规律、趋势及存在的差异和原因.     

优秀田径运动员心率变异性分析

目的:分析优秀田径运动员心率变异性(HRV)特征,为HRV在运动员选材、机能评定等应用提供理论依据。方法:选取江苏省专业运动队优秀田径运动员和普通健康人各25名进行连续5min心电图时域和频域记录获得HRV指标,以普通健康人为对照分析优秀田径运动员HRV特征。结果:(1)女运动员VLF低于男运动员(P<0.05),其余指标无性别差异。(2)优秀田径运动员SDNN、RMSSD、PNN50、TP、HF、VLF均高于普通健康人(P<0.05或P<0.01);LF、LF/HF二者无差异(P>0.05)。结论:(1)优秀田径运动员自主神经活性和迷走神经的紧张性没有性别差异,安静时男性运动员拥有较高的交感神经张力。(2)优秀田径运动员安静时比普通健康人拥有更强的心脏自主神经活性、更高的迷走神经紧张性和交感神经兴奋性,迷走和交感神经均衡性无差异。     

Objective and subjective methods for quantifying training load in wheelchair basketball small-sided games

The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards’ training load and Stagno’s training impulses (TRIMP_MOD) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards’ training load and TRIMP_MOD), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P < 0.05; effect size (ES) = 0.66, moderate] and fourth bouts (P < 0.05; ES = 0.64, moderate) than in the first bout, but other measures did not differ. Mean correlations indicated a trivial and small relationship among HR-based and RPE-based training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other.     

Effects of heat acclimation on hand cooling efficacy following exercise in the heat

This study examined the separate and combined effects of heat acclimation and hand cooling on post-exercise cooling rates following bouts of exercise in the heat. Seventeen non-heat acclimated (NHA) males (mean ± SE; age, 23 ± 1 y; mass, 75.30 ± 2.27 kg; maximal oxygen consumption [VO₂ max], 54.1 ± 1.3 ml·kg^?1·min^?1) completed 2 heat stress tests (HST) when NHA, then 10 days of heat acclimation, then 2 HST once heat acclimated (HA) in an environmental chamber (40°C; 40%RH). HSTs were 2 60-min bouts of treadmill exercise (45% VO₂ max; 2% grade) each followed by 10 min of hand cooling (C) or no cooling (NC). Heat acclimation sessions were 90–240 min of treadmill or stationary bike exercise (60–80% VO₂ max). Repeated measures ANOVA with Fishers LSD post hoc (α < 0.05) identified differences. When NHA, C (0.020 ± 0.003°C·min^?1) had a greater cooling rate than NC (0.013 ± 0.003°C·min^?1) (mean difference [95%CI]; 0.007°C [0.001,0.013], P = 0.035). Once HA, C (0.021 ± 0.002°C·min^?1) was similar to NC (0.025 ± 0.002°C·min^?1) (0.004°C [?0.003,0.011], P = 0.216). Hand cooling when HA (0.021 ± 0.002°C·min^?1) was similar to when NHA (0.020 ± 0.003°C·min^?1) (P = 0.77). In conclusion, when NHA, C provided greater cooling rates than NC. Once HA, C and NC provided similar cooling rates.     

Effect of a Brazilian Jiu-jitsu-simulated tournament on strength parameters and perceptual responses

This study aimed to analyse the effects of a simulated Brazilian jiu-jitsu (BJJ) tournament on vertical jump performance, grip strength test and perceived effort responses. 22 male BJJ athletes participated in a simulated tournament consisting of three 7 min matches separated by 14 min of rest. Kimono grip strength test (KGST), counter movement jump (CMJ) and rate of perceived exertion (RPE) were measured before and after each match, while RPE of specific areas was assessed after three matches. ANOVA for repeated measures was used to compare strength parameters after each match with the level of significance set at 5%. The key results showed a significant decrease of jump height (p = 0.001) and net vertical impulse in the CMJ (p = 0.031), as well as a reduction of the number of reps in the KGST (p < 0.001). A significant increase of RPE was found throughout the matches (p < 0.001). Considering the RPE in specific areas, no differences were observed between the upper and lower body (p = 0.743). We conclude that the BJJ simulated tournament generated a decrease of performance in both upper and lower limbs and provoked a progressive increase in the effort perception over the matches.     

Thermoneutral immersion exercise accelerates heart rate recovery: A potential novel training modality

This study compared heart rate recovery (HRR) after incremental maximal exercise performed at the same external power output (P_ext) on dry land ergocycle (DE) vs. immersible ergocycle (IE). Fifteen young healthy participants (30?±?7 years, 13 men and 2 women) performed incremental maximal exercise tests on DE and on IE. The initial P_ext on DE was 25?W and was increased by 25?W/min at a pedalling cadence between 60 and 80?rpm, while during IE immersion at chest level in thermoneutral water (30°C), the initial P_ext deployment was at a cadence of 40?rpm which was increased by 10?rpm until 70?rpm and thereafter by 5?rpm until exhaustion. Gas exchange and heart rate (HR) were measured continuously during exercise and recovery for 5?min. Maximal HR (DE: 176?±?15 vs. IE 169?±?12?bpm) reached by the subjects in the two conditions did not differ (P?>?.05). Parasympathetic reactivation parameters (ΔHR from 10 to 300?s) were compared during the DE and IE HR recovery recordings. During the IE recovery, parasympathetic reactivation in the early phase was more predominant (HRR at Δ10–Δ60?s, P?<?.05), but similar in the late phase (HRR at Δ120–Δ300?s, P?>?.05) when compared to the DE condition. In conclusion, incremental maximal IE exercise at chest level immersion in thermoneutral water accelerates the early phase parasympathetic reactivation compared to DE in healthy young participants.     

Maximal heart rate declines linearly with age independent of cardiorespiratory fitness levels

There have been many conflicting observations between the linear or curvilinear decline in maximal heart rate (HR_max) with age. The aim of this study was to determine if linear or curvilinear equations would better describe the decline in HR_max with age in individuals of differing cardiorespiratory fitness (CRF) levels. Treadmill cardiopulmonary exercise test (CPX) results from participants (1510 men and 1134 women; 18–76 years) free of overt cardiovascular disease were retrospectively examined using cross-sectional and longitudinal study designs. Participants completing ≥2 CPX with ≥1 year between test dates were included in the longitudinal analysis (325 men and 150 women). Linear and quadratic regressions were applied to age and HR_max for the whole cohort and respective CRF groups (high, moderate, and low, relative to age and gender normative values). To test for differences among linear, quadratic, and polynomial equations, the change in R² (cross-sectional analysis) and Bayesian information criterion (BIC) (longitudinal analysis) from the linear to the more complex models were calculated. The quadratic or polynomial regression in the cross-sectional analysis, marginally improved the variance in HR_max explained by age compared to the linear regression for the whole cohort (0.2%), moderate fit group (0.3%), and low fit group (0.8%). With no improvements in the high fit group. BIC did not improve for any CRF category in the longitudinal analysis. In conclusion, the minimal differences among linear, quadratic, and polynomial equations in the respective CRF groups, emphasizes the use of linear prediction equations to estimate HR_max.     

房产税改革的方案选择及财税效应分析

对房产持有环节开征房产税具有国际通用的合理性和合法性,房产税改革是新一轮国家财税体制改革的重要内容。对国内主要城市的房产税改革方案及其财税效应分析表明：采用无差别税率征税方案的优势在于减少征管成本、确保居民纳税义务的公平性,劣势在于造成纳税人税负过重、不利于调节财富分配差距;而按住房面积采用递进税率征税方案的优势在于能够调节贫富差距、体现“量能负担”原则,劣势在于容易被纳税人投机取巧而逃避高税率和监管。权衡利弊,“每人享受一定面积的减免,根据住房面积大小、基于公告价值或评估价值按不同税率征收”的方案,可作为今后房产税改革的主要方向。