高温高湿环境下高强度军事训练对肾脏组织的损伤

目的 探讨高温高湿环境下高强度军事训练对肾脏组织的损伤作用,为高温高湿环境下训练致肾脏损伤的防治提供依据.方法 400名守礁官兵按入伍时间及训练环境分为4组(高温高湿新兵组、高温高湿老兵组、常温常湿新兵组、常温常湿老兵组),进行10 km武装越野训练,在训练前后留尿标本进行尿液常规检查.以酶联免疫吸附法( ELISA)检测尿N-乙酰-β-D-氨基葡萄糖苷水解酶(NAG)和尿视黄醇结合蛋白(RBP);抽取静脉血检测血肌苷(Cr)及尿素氮(BUN),并对各项检验结果进行统计分析.结果 高温高湿新兵组训练后尿量为(25.2±8.5) ml,明显少于其他3组,差异均有统计学意义(P＜0.05);血尿阳性率13％,血红蛋白尿阳性率17％,蛋白尿阳性率68％,N-乙酰-β-D-氨基葡萄糖苷水解酶/肌酐异常率84％,尿视黄醇结合蛋白异常率89％,均明显高于其他3组,差异均有统计学意义(P＜0.05).但各组训练前后Cr、BUN均无明显变化(P＞0.05).结论 高温高湿环境下训练对官兵肾脏的影响较大,对新兵的影响更明显,老兵表现出较好的热耐受力和适应性.     

高温高湿环境下负压伤口疗法对创面愈合的影响

目的探讨高温高湿环境下局部负压伤口治疗对创伤愈合的影响。方法以兔背部皮肤全层皮肤缺损的急性创面为模型,将24只创伤兔按随机数字表法随机分为常温对照组、常温实验组、高温对照组、高温实验组,每组6只。实验组给予局部负压伤口治疗,对照组用纱布覆盖,不给予负压引流。在相应干预后的不同时间对各组动物的创面大体情况、创面愈合时间、创面愈合百分比、病理形态学进行观察和检测。结果高温对照组与常温对照组比较,创面愈合时间、创伤后7d创面愈合率、创面感染率及组织损伤程度显著增高(P<0.05),而实验组较相应的对照组则显著降低(P<0.05)。结论高温高湿环境是阻碍创面愈合的重要因素之一,局部负压伤口疗法具有促进创面愈合的作用。     

高温高湿环境下负压伤口疗法对创面细菌学定量的影响

目的探讨高温高湿环境下局部负压伤口治疗对创伤伤口的抗菌作用。方法以兔背部皮肤全层皮肤缺损的急性创面为模型,将24只创伤兔随机分为常温对照组、常温实验组、高温对照组、高温实验组,每组6只。实验组给予局部负压伤口治疗,对照组用纱布覆盖,不给予负压引流。观察伤口细菌数量的变化和伤口大体情况。结果高温对照组创面细菌量随着时间的延长呈直线上升趋势,与常温对照组、常温实验组比较差异有统计学意义(P<0.05),高温实验组细菌数量增长显著低于高温对照组(P<0.05)。结论高温高湿环境有利于细菌生长繁殖,局部负压伤口疗法具有显著的隔离和抑制细菌生长的作用。     

局部伤口负压引流对高热复合创伤兔体温的影响

目的探讨高温高湿环境下局部伤口负压引流治疗对兔体温的影响。方法以兔背部皮肤全层皮肤缺损的急性创面为模型,将24只创伤兔随机分为常温对照组、常温实验组、高温对照组、高温实验组,每组6只。实验组给予局部伤口负压引流治疗,对照组用纱布覆盖,不给予负压引流。创伤后每1 h监测肛温(Tr)1次。结果高温暴露的两组兔肛温较常温环境下的两组明显增高(P<0.05),与高温对照组比较,高温实验组肛温明显降低(P<0.05)。结论高温高湿环境是导致创伤兔肛温升高的重要因素,局部伤口负压引流疗法可有效缓解高温复合创伤兔的肛温,阻止热损伤对创面局部及全身的影响。     

高温高湿环境下负压伤口疗法对创面组织水肿及病理学变化的影响

目的探讨高温高湿环境下局部负压伤口治疗对兔创面组织水肿及病理变化的影响。方法以兔背部皮肤全层皮肤缺损的急性创面为模型,将24只创伤兔随机分为常温对照组、常温实验组、高温对照组、高温实验组,每组6只。实验组给予局部负压伤口治疗,对照组用纱布覆盖,不给予负压引流,在创伤后0、4、6 h分别通过光镜对创面组织病理形态学进行观察及用干湿法对各组动物的创面组织含水率检测。结果高温组较相应的常温组创面的组织含水率高(P<0.05)、病理变化严重,实验组较相应的对照组创面的组织含水率低(P<0.05)、病理变化轻。结论高温高湿创面肌肉组织水肿及病理损伤严重,局部负压伤口疗法可以有效减轻创面水肿及组织损伤程度。     

两周热环境训练结合营养干预对优秀女子网球运动员营养和机能状况的影响

目的:探讨高温、训练和营养干预对优秀女子网球运动员营养和机能状况的影响。方法:在2周热环境训练中对备战北京奥运会的8名国家队女子网球运动员进行营养干预,并在干预前(7月19日)和干预后(8月2日)测试其营养、形态和生化指标。结果:营养干预后,膳食总热能、碳水化合物和蛋白质摄入比例分别显著增加11.0%,3.2%和14.8%(P<0.05),均高于90%推荐值,脂肪摄入比例显著下降17.8%(P<0.05)。训练中补水、补糖和补盐量显著提高(P<0.05)。运动员瘦体重明显增加(P<0.05),体脂百分比显著降低(P<0.05)。血红蛋白、血尿素、肌酸激酶、睾酮和皮质醇指标维持正常。结论:合理膳食、营养补剂以及科学训练能改善网球运动员的营养和机能状况,有助于运动员热适应能力的提高。     

中医药改善女子柔道运动员降控体重期训练效果个案报道

目的：采用中医药干预改善女子柔道运动员伍××赛前降控体重期的训练效果。方法：在降重方法、赛前训练计划和其它措施相同的情况下，针对30岁女运动员伍××在赛前降控体重过程中出现的问题，如白细胞降低、易感冒和易疲劳等，在2019年下半年冠军赛赛前6周分阶段运用中医药对运动员进行针对性干预，不同阶段运用不同的中药组方，并与2019年上半年锦标赛赛前降控体重时未运用中医药干预的训练效果进行比较；生化指标检测包括每周一清晨空腹采静脉血测血尿素（Urea）、肌酸激酶（CK）、白细胞（WBC）、血红蛋白（HGB）等。结果：分阶段运用中医药进行针对性干预后，运动员血白细胞呈明显上升、血红蛋白也明显增加，运动员赛前训练水平和质量得到了提高，赛前竞技状态调整到了较好水平，并在接下来的比赛中取得了优异成绩。结论：本研究结果表明，对于降控体重较多的运动员，分阶段运用中医药进行针对性干预，可以明显改善运动员降控体重训练效果。     

减体重对女子举重运动员运动能力的影响及营养干预的效果

目的探讨在运动训练中的慢速减体重、赛前快速降体重和赛前体能恢复期间实施营养学干预对运动员减重后运动能力的影响.方法12名女子举重运动员随机分成实验组和对照组,每组6人.实验组和对照组运动员进行统一的运动训练并采用等同能量的饮食.实验组减重期间服用减重棒、维生素和电解质等运动营养食品,在减重后的恢复期服用快速能量补充制剂和维生素电解质强化运动营养补充;对照组服用相应的安慰剂.分别在减重前后对两组对象进行有氧能力和无氧能力测试.运动员在减重实验前与实验期间填写饥饿度自评表.结果实验组运动员体重从实验前的67.4±14.2 kg下降到快速减重后的64.6±14.1 kg,对照组从67.4±15.5 kg下降到64.3±15.4 kg.实验组在快速减重后的恢复阶段,6分钟乳酸稳态实验后即刻血乳酸浓度、心率以及主观疲劳评分显著低于对照组.两组在慢减期后、快减期后和恢复阶段,30秒Wingate测试单位体重的最大功率、平均功率和最小功率均无显著性差异,但实验组在快速恢复第1天和第3天单位体重的最大功率显著高于实验前.结论科学地减少饮食热量摄入能够按照既定的目标减轻体重;快速能量补充制剂和维生素、电解质的复合补充制剂能够明显促进运动员减体重后身体快速恢复,保持无氧能力和有氧能力;以魔芋为主要成分的减重棒能明显减轻减体重期间的饥饿感.     

艾灸对大负荷训练期间男子中长跑运动员T淋巴细胞亚群的影响

目的:探讨艾灸对大负荷训练期间男子中长跑运动员外周血CD3+、CD4+、CD8+T淋巴细胞亚群的调节作用。方法:12名中长跑男子运动员随机分为对照组(6名)和实验组(6名),在准备期的大负荷训练阶段进行实验。第1周为适应训练周,第2～4周为大负荷训练期,第5周为调整训练周。大负荷训练期间每天训练2次,每周训练6天;实验组每天下午训练后,分别交替选取(1)关元穴、足三里穴(双)和(2)关元穴、三阴交穴(双)两组穴位进行艾灸治疗,每天灸一组,使用艾灸器内置纯艾条,分别置于上述穴位上温和灸刺激,每次30 min,每周治疗6次;从大负荷训练周开始至调整训练周结束,共灸治4周。对照组同实验组进行相同的训练和生活,但不进行艾灸治疗。分别在大负荷运动训练前、大负荷运动训练3周后、调整训练1周后采用流式细胞仪检测运动员外周血CD3+、CD4+、CD8+T淋巴细胞亚群相对含量。结果:(1)实验组大负荷运动训练3周后CD3+、CD4+、CD8+T细胞比大负荷前明显增加(P<0.05),且CD3+比对照组大负荷后明显增高(P<0.05);(2)调整训练1周后,对照组CD3+、CD4+、CD8+T细胞与大负荷训练后相比均明显下降(P<0.05),且低于运动员正常值范围,实验组CD3+、CD4+、CD8+T细胞比大负荷训练后降低(P<0.05),且CD3+、CD8+T细胞显著高于对照组同期(P<0.05);(3)对照组大负荷训练3周后CD4+/CD8+比值较大负荷训练前明显上升(P<0.05),调整训练1周后仍继续上升(P>0.05),实验组大负荷训练后升高,调整训练1周后恢复,前后3次检测值差异均无统计学意义(P>0.05)。结论:艾灸能提高男子中长跑运动员大负荷运动训练期间CD3+、CD4+、CD8+T淋巴细胞亚群的含量,可防止CD3+、CD4+、CD8+T淋巴细胞亚群的低下,预防CD4+/CD8+平衡失调。     

12周循环抗阻训练对男子大学生心血管动力学参数的影响

目的:研究循环抗阻训练(CRT)对普通男性大学生心血管动力学参数的影响。方法:28名健康男性受试者随机分为实验组和对照组,实验组进行12周强度为40～60%1RM的循环抗阻训练干预,每周3次,每次12～15组、1～3个循环、约30～45分钟;对照组不进行任何干预。实验前后用无创性心血管健康监测仪检测脉搏波,分析心血管动力学流变参数的变化。结果:实验组实验前后每分心输出量(CO)明显提高(P<0.01),心脏指数(CI)、左心室每搏做功指数(LVSWI)增加(P<0.05);平均收缩压(MSP)、平均舒张压(MDP)、平均动脉压(MAP)降低(P<0.05),平均总周阻力(TR)和标准周阻(STR)下降十分显著(P<0.01),血管扩张系数(ETK)和血管顺度(AC)无明显变化(P>0.05);微循环半更新时间(ALT)和微循环平均滞留时间(TM)明显加快(P<0.01),微循环半更新率(ALK)提高显著(P<0.05),而对照组实验前后各指标变化不明显(P>0.05);两组实验后各指标相比,HR、TR、STR、ALT、TM等指标明显降低(P<0.01),每搏心输出量(SV)增加显著(P<0.01)。结论:12周循环抗阻训练可有效提高心脏的泵血机能,降低动脉血压,改善组织微循环状况。     

Creatine-dextrose and protein-dextrose induce similar strength gains during training.

BACKGROUND: Creatine supplementation during resistance exercise training has been reported to induce greater increases in fat-free mass (FFM), muscle fiber area, and strength when compared with a placebo. We have recently shown that timing of nutrient delivery in the postexercise period can have positive effects on whole body protein turnover (B. D. Roy et al., Med Sci Sports Exerc. 32(8):1412-1418, 2000). PURPOSE: We tested the hypothesis that a postexercise protein-carbohydrate supplement would result in similar increases in FFM, muscle fiber area, and strength as compared with creatine monohydrate (CM), during a supervised 2-month resistance exercise training program in untrained men. METHODS: Young healthy male subjects were randomized to receive either CM and glucose (N = 11; CM 10 g + glucose 75 g [CR-CHO] (CELL-Tech)) or protein and glucose (N = 8; casein 10 g + glucose 75 g [PRO+CHO]), using double-blinded allocation. Participants performed 8 wk of whole body split-routine straight set weight training, 1 h.d(-1), 6 d.wk(-1). Measurements, pre- and post-training were made of fat-free mass (FFM; DEXA), total body mass, muscle fiber area, isokinetic knee extension strength (45 and 240 degrees.s(-1)), and 1 repetition maximal (1RM) strength for 16 weight training exercises. RESULTS: Total body mass increased more for CR-CHO (+4.3 kg, 5.4%) as compared with PRO-CHO (+1.9 kg, 2.4%) (P < 0.05 for interaction) and FFM increased after training (P < 0.01) but was not significantly different between the groups (CR-CHO = +4.0 kg, 6.4%; PRO-CHO = +2.6 kg, 4.1%) (P = 0.11 for interaction). Muscle fiber area increased similarly after training for both groups (approximately 20%; P < 0.05). Training resulted in an increase in 1RM for each of the 16 activities (range = 14.2-39.9%) (P < 0.001), isokinetic knee extension torque (P < 0.01), with no treatment effects upon any of the variables. CONCLUSIONS: We concluded that postexercise supplementation with PRO-CHO resulted in similar increases in strength after a resistance exercise training program as compared with CR-CHO. However, the greater gains in total mass for the CR-CHO group may have implications for sport-specific performance.     

游泳训练和高脂膳食对雄性大鼠发育中及成年后脂肪细胞数目的影响

目的:研究运动训练和高脂膳食两种因素对雄性大鼠生长发育过程中及成年后脂肪细胞数目的影响。方法:4周龄雄性SD大鼠随机分为普通饮食和高脂膳食两组,每组再分两个亚组:安静组和运动组,即普通饮食安静组(C组),普通饮食运动组(E组),高脂膳食安静组(H组)和高脂膳食运动组(HE组)。采用游泳运动,每次60分钟开始,递增至90分钟,3次/周。分别在干预4周、8周、12周后取材,完整剥离内脏脂肪组织,制备石蜡切片,测定脂肪细胞直径,计算脂肪细胞总数。结果:①4周时,HE组内脏脂肪组织重量显著高于E组;8周时,E组显著低于C组;12周时,H组高于C组和HE组,E组显著低于C组和HE组。8周和12周时,各组内脏脂肪重量均显著高于其对应4周组;12周时,除E组外,其它3组均高于其对应8周组。②4周时,H组内脏脂肪细胞直径大于C组和HE组;8周时,H组大于C组;12周时,E组小于C组和HE组,HE组小于H组。8周和12周时各组内脏脂肪细胞体积均大于4周时,12周时C组、H组和HE组均大于8周时。③4周时,各组间大鼠内脏脂肪细胞数目差异均无统计学意义;8周时,E组小于C组和HE组;12周时,H组大于C组和HE组。C组8周时大于4周时;H组12周时大于4周和8周时。以上差异均具有统计学意义,P<0.05或P<0.01。结论:高脂膳食提高雄性大鼠发育期脂肪细胞数目,运动训练可减弱高脂膳食提高脂肪细胞数目的作用。     

补充谷氨酰胺对递增负荷训练游泳运动员血液谷氨酰胺水平的影响

目的:探讨补充谷氨酰胺(Gln)对递增负荷训练游泳运动员血液谷氨酰胺水平的影响及其作用机制。方法:广东省游泳运动员12名,随机分为实验组(T,补充Gln,n=5)及对照组(C,n=7),进行为期2个月的递增强度负荷训练。实验前1天上午,运动员空腹采集肘静脉血,分别测定血浆Gln、Hb、血清CK及皮质醇(Cortisol);实验第29天(T组服用Gln第1天)晨,运动员空腹进行第2次血样采集与分析;即日起,T组2次大运动量训练结束后立即补充Gln(0.15g/kgbodymass),持续服用28天。分别于实验第36天(T组服用Gln第7天)和实验第57天(T组服用Gln第28天),对T、C组运动员进行血样分析。结果:所有运动员正常训练4周后,血浆Gln水平显著升高(P<0.01)。实验组服用Gln第28天,血浆Gln浓度显著高于服用Gln第7天(1317.64±401.445μmmol/Lvs.954.88±317.87μmmol/LP<0.05)。对照组训练5周后较训练4周时血浆Gln水平无显著性变化(1280.46±441.73μmmol/Lvs.1251.37±292.06μmmol/L,P>0.05),实验8周后,血浆Gln水平较5周时显著下降(1280.46±441.73μmmol/Lvs.891.64±322.37μmmol/L,P<0.05)。T组服用Gln7天后,皮质醇水平显著升高(P<0.01)。补充Gln后,T组Hb水平显著上升,CK水平显著下降,C组Hb、CK未见明显变化。结果表明,血浆Gln水平会随训练产生适应性变化,补充外源性Gln可以在一定程度上削弱由训练引起的血浆Gln水平下降的程度。     

急性高容血液稀释对颅脑外伤急诊手术患者肾功能的影响

目的 观察两种羟乙基淀粉(hydroxyethyl starch,HES)(万汶和贺斯)急性高容血液稀释(acute hypervolemic hemodilution,AHH)对颅脑外伤急诊手术患者血流动力学及肾功能的影响.方法 本研究共纳入54例颅脑外伤急诊手术患者,随机分为万汶( AHH130)组、贺斯(AHH200)组和乳酸林格液(LR)组,每组18例,均采用静吸复合全身麻醉.术中监测心电图(ECG)、平均动脉压(MAP)、中心静脉压(CVP)和脉氧饱和度(SpO2);检测AHH前(T0)、手术结束时(T1)、术后4 h(T2)、术后第1天(T3)、术后第2天(T4)和术后第3天(T5)时血尿素氮(BUN)、血尿肌酐(BCr、UCr)、尿白蛋白(ALB)和尿α1-微球蛋白( α1 - MG)的变化;计算肌酐清除率(CCr)和钠清除分数(FSC);记录尿量、补液、失血及输血情况.结果 三组HR、CVP、MAP在各时相点的变化均在正常范围内,组间及组内比较差异无统计学意义(P＞0.05).三组术中失血量和尿量差异无统计学意义(P＞0.05),术中补液量和异体血输入量AHH130组和AHH200组明显少于LR组(P＜0.01).三组BUN、BCr和尿ALB在各时相点组间和组内比较差异无统计学意义(P＞0.05).AHH后,AHH130组和AHH200组尿α1 - MG浓度均明显升高(P＜0.01),至T5虽有所下降,但仍明显高于T0水平(P＜0.01),且各时相点尿α1 - MG浓度明显高于LR组(P＜0.05).AHH后AHH130组和AHH200组CCr呈下降趋势,在T2最低,与T0比较差异有统计学意义(P＜0.01);而后回升,至T5时接近T0水平.各组FSC在AHH后均有轻度升高,T2最明显,但与T0比较差异无统计学意义(P＞0.05).其他各时相点组内和组间比较差异均无统计学意义(P＞0.05).各组各时相点肾功能所有数值均在正常范围内变化.结论 HES(万汶和贺斯)AHH对术前肾功能正常的颅脑外伤急诊手术患者的肾功能均无明显影响,能明显减少异体血输注,是安全可行的血液保护措施.     

Effects of oral creatine and resistance training on myosin heavy chain expression

PURPOSE: This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on muscle strength and myosin heavy chain (MHC) isoform mRNA and protein expression. METHODS: Twenty-two untrained male subjects were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after 12 wk of heavy resistance training. PLC and CRT trained thrice weekly using three sets of 6-8 repetitions at 85-90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g.d-1 of Cr for 12 wk, whereas PLC consumed the equal concentration of placebo. RESULTS: There were no significant differences for percent body fat (P > 0.05). However, for total body mass, fat-free mass, thigh volume, muscle strength, and myofibrillar protein, CRT and PLC exhibited significant increases after training when compared to CON (P < 0.05), whereas CRT was also significantly greater than PLC (P < 0.05). For Type I, IIa, and IIx MHC mRNA expression, CRT was significantly greater than CON and PLC, whereas PLC was greater than CON (P < 0.05). For MHC protein expression, CRT was significantly greater than CON and PLC for Type I and IIx (P < 0.05) but was equal to PLC for IIa. CONCLUSION: Long-term Cr supplementation increases muscle strength and size, possibly as a result of increased MHC synthesis.     

Elite Kenyan endurance runners are hydrated day-to-day with ad libitum fluid intake

Previous studies of elite Kenyan endurance runners reported that athletes did not consume liquids before or during training and infrequently consumed modest amounts of liquids after training that contributed to low daily fluid intake. PURPOSE: To assess hydration status of elite Kenyan endurance runners during an important training period. METHODS: Hydration status was monitored in fourteen elite Kenyan endurance runners over a 5-d training period 1 wk prior to the Kenyan national trials for the 2005 IAAF Athletics World Championships by measuring body mass, urine osmolality, total body water, and daily fluid intake. Dietary sodium (Na) intake was estimated using a 5-d nutritional diary and biochemical analysis, whilst [Na] was determined in urine and sweat. Intestinal temperature was monitored continuously during training sessions. RESULTS: Daily fluid intake was consistent with previous observations. There was a significant body mass loss during the morning, interval, and afternoon training sessions (P < 0.05). Nevertheless, mean total body water and pretraining body mass were well maintained day-to-day throughout the 5-d recording period (P = 0.194 and P = 0.302, respectively). Furthermore, there was no significant difference between the osmolality of the morning urine sample and the evening sample (P = 0.685). Mean Na intake was not significantly different to Na loss in sweat and urine (P = 0.975). No athlete showed signs or symptoms of heat strain at any time. CONCLUSIONS: These results demonstrate that elite Kenyan endurance runners remain well hydrated day-to-day with an ad libitum fluid intake; a pattern and volume of fluid intake that is consistent with previous observations of elite Kenyan endurance runners.     

Exercise attenuates the weight-loss-induced reduction in muscle mass in frail obese older adults

PURPOSE: To evaluate the effect of adding exercise to a hypocaloric diet on changes in appendicular lean mass and strength in frail obese older adults undergoing voluntary weight loss. METHODS: Thirty frail older (age, 70 +/- 5 yr) obese (body mass index, 37 +/- 5 kg.m) adults were randomly assigned to 6 months of diet/behavioral therapy (diet group, n = 15) or diet or behavioral therapy plus exercise that incorporated progressive resistance training (PRT; diet + exercise group; n = 15). Body composition was assessed using dual-energy x-ray absorptiometry, and muscle strength was assessed using one-repetition maximum. The volume of upper extremity (UE) and lower extremity (LE) exercise training was determined by multiplying the average number of repetitions performed by the average weight lifted during the first three exercise sessions and during the last three exercise sessions of the study. RESULTS: The diet and the diet + exercise groups had similar (P > 0.05) decreases in weight (10.7 +/- 4.5 vs 9.7 +/- 4.0 kg) and fat mass (6.8 +/- 3.7 vs 7.7 +/- 2.9 kg). However, the diet + exercise group lost less fat-free mass (FFM; 1.8 +/- 1.5 vs 3.5 +/- 2.1 kg), LE lean mass (0.9 +/- 0.8 vs 2.0 +/- 0.9 kg), and UE lean mass (0.1 +/- 0.2 vs 0.2 +/- 0.2 kg) than the diet group (P < 0.05). The diet + exercise group had greater increases in percent of weight as FFM (FFM / weight x 100) than the diet group (7.9 +/- 3.3 vs 5.4 +/- 3.7%; P < 0.05). Despite lean mass losses, the diet + exercise group increased UE and LE strength in response to exercise (17-43%), whereas the diet group maintained strength. The volume of UE and LE exercises correlated with the amount of UE and LE lean mass (r = 0.64-0.84; P < 0.05). CONCLUSION: Exercise added to diet reduces muscle mass loss during voluntary weight loss and increases muscle strength in frail obese older adults. Regular exercise that incorporates PRT should be used to attenuate muscle mass loss in frail obese older adults on weight-loss therapy.     

Effect of training on postural control in figure skaters: a randomized controlled trial of neuromuscular versus basic off-ice training programs.

OBJECTIVES: To compare the effect of a neuromuscular training program and a basic exercise program on postural control in figure skaters. DESIGN: Two groups; parallel design; prospective, randomized controlled trial. SETTING: Postural control laboratory, arenas, September 2001 to December 2002. PARTICIPANTS: Forty-four young, healthy figure skaters (18 years +/- 3 years). INTERVENTIONS: Participants were randomly assigned to receive a neuromuscular training program (n = 22) or a basic exercise training program (n = 22). Both programs were completed 3 times per week for 4 weeks, and each session was supervised. MAIN OUTCOME MEASUREMENTS: Participants completed baseline and postintervention measures of postural control on a force plate. Postural control was quantified as the center of pressure (CoP) path length during tests of single-limb standing balance that mimicked figure skating skills and challenged the postural control system to varying degrees. The primary outcome measure was the CoP path length observed during a landing jump test completed with eyes closed. RESULTS: The post intervention CoP path lengths during the more challenging tests were significantly (P < 0.05) lower (indicating better postural control) for the neuromuscular trained group than for the basic exercise-trained group. For the landing jump test completed with eyes closed, the percent improvement in the neuromuscular trained group was significantly greater (mean = 21.0 +/- 22.0%) than the basic exercise trained group (mean = -4.9 +/- 24.9%; P < 0.05). The magnitude of improvement in the neuromuscular-trained group ranged from approximately 1% to 21%, depending on the specific postural control test used. CONCLUSIONS: The results suggest that off-ice neuromuscular training can significantly improve postural control in figure skaters, whereas basic exercise training does not.     

Physiological consequences of U.S. Army Ranger training

PURPOSE: Soldiers are expected to maintain a high degree of physical readiness as operational demands can severely degrade performance capabilities. This study examined the physiological consequences of U.S. Army Ranger training on strength, power, body composition, and somatotrophic hormones. METHODS: In an intensive 8-wk military training course that included an average daily energy deficit of 1000 kcal.d, lower-body power output, maximal lifting strength, body composition, and serum concentrations of several somatotrophic hormones were measured in 50 male soldiers (24.6 +/- 4.4 y; 176.1 +/- 7.8 cm; 78.4 +/- 8.7 kg; 14.7 +/- 4.2% body fat) before and after the course. RESULTS: Vertical jump height (-16%), explosive power output (-21%), maximal lifting strength. (-20%), body mass (-13%), fat-free mass (-6%), and fat mass (-50%) declined (P < 0.05) after the training course. Circulating total testosterone and insulin-like growth factor-I (IGF-I) experienced significant (P < 0.05) declines, and cortisol was significantly increased. Lower-body power output, but not maximal lifting strength, correlated with changes in fat-free mass. IGF-I and cortisol, but not total testosterone, were correlated with losses of tissue mass. CONCLUSION: Lower-body power output, estimated from vertical jump height and body mass, is a sensitive and field expedient measure that can be used to assess the influence of caloric deficit on physical performance after 8 wk of U.S. Army Ranger training. With severe weight loss (>or=13% of body mass), IGF-I and cortisol correlate more closely with soft-tissue tissue adaptations than does testosterone.