Physiological Responses to Maximal Treadmill and Handweighted Exercise

Abstract

The purpose of this investigation was to compare the peak physiological responses among four protocols that employed different amounts of handweighted exercise in 16 males (aged 26.3 ± 4.1 years). The four protocols were (a) uphill treadmill running (UR; 3.36 m-s¹, 2.5% grade increase-3 min¹); (b) uphill treadmill walking while pumping 1.36kg handweights (HW) (UWHW; 1.79ms¹, 5.0% grade increase-3 min¹; (c) treadmill walking while pumping .91-kg HW (WHW; 1.79 m-s¹, 0% grade, .91kg HW increase-3 min¹); and (d) standing in place and pumping HW (SHW; arm work as described in WHW). It was hypothesized that the peak responses would be inversely proportional to the estimated muscle mass activated (i.e., UR = UWHW > WHW > SHW). Dependent variables included peak oxygen uptake (VO₂ peak), peak heart rate (HRpeak), peak ventilation (V_epeak), and peak respiratory exchange ratio (RERpeak). No differences were noted between UR and UWHW with respect to any of the dependent variables. All variables (except RERpeak) were greater (p < .01) in UR and UWHW than either WHW or SHW. RERpeak was greater (p < .01) in UR and UWHW than in WHW. VO₂peak and HRpeak were greater (p < .01) in WHW when compared to SHW. Mean VO₂peak was 97.5, 69.7, and 60% of UR for UWHW, WHW, and SHW, respectively. Therefore, walking and pumping handweights provides a maximal stimulus to the oxygen transport system.     

Submaximal Treadmill Exercise Test to Predict VO2max in Fit Adults

This study was designed to develop a single-stage submaximal treadmill jogging (TMJ) test to predict VO₂max in fit adults. Participants (N?=?400; men?=?250 and women?=?150), ages 18 to 40 years, successfully completed a maximal graded exercise test (GXT) at 1 of 3 laboratories to determine VO₂max. The TMJ test was completed during the first 2 stages of the GXT. Following 3 min of walking (Stage 1), participants achieved a steady-state heart rate (HR) while exercising at a comfortable self-selected submaximal jogging speed at level grade (Stage 2). Gender, age, body mass, steady-state HR, and jogging speed (mph) were included as independent variables in the following multiple linear regression model to predict VO₂max (R?=?0.91, standard error of estimate [SEE]?=?2.52 mL?·?kg^?1?·?min^?1): VO₂max (mL?·?kg^?1?·?min^?1)?=?58.687?+?(7.520 × Gender; 0?=?woman and 1?=?man)?+?(4.334 × mph) ? (0.211 × kg) ? (0.148 × HR) ? (0.107 × Age). Based on the predicted residual sum of squares (PRESS) statistics (R_PRESS?=?0.91, SEE _PRESS?=?2.54 mL?·?kg^?1?·?min^?1) and small total error (TE; 2.50 mL?·?kg^?1?·?min^?1; 5.3% of VO₂max) and constant error (CE; ?0.008 mL?·?kg^?1?·?min^?1) terms, this new prediction equation displays minimal shrinkage. It should also demonstrate similar accuracy when it is applied to other samples that include participants of comparable age, body mass, and aerobic fitness level. This simple TMJ test and its corresponding regression model provides a relatively safe, convenient, and accurate way to predict VO₂max in fit adults, ages 18 to 40 years.     

Age and Cardiovascular Response to Submaximal Treadmill Exercise in Males

Abstract

The primary purpose of this investigation was to determine the relative importance of the attributes that student–athletes use when determining their choice of a university. A second purpose was to compare previous athletic institutional choice studies with the results of this study to determine if the most important attributes were similar and to compare and contrast methodologies. Six hundred five Division I student–athletes (344 baseball players and 261 softball players) from all eight national geographic regions of the NCAA participated in this study. The experimental procedure was based on Information Integration Theory and a 2¹⁰ fractional factorial design that resulted in 32 “choice sets.” These choice sets were composed of universities described by 10 attributes. This framework required that the student–athletes choose from among three university profiles, thereby realistically simulating the decision process. The results for the aggregate sample show that the “Amount of Scholarship” attribute was the most important factor in the institutional choice process. Many demographic variables were analyzed (sex, race, amount of scholarship received as a freshman, amount of perceived financial need, self-reported grade-point average, questionnaire completion procedures, in-state/out-of-state status, NCAA region, and rank in high school) in conjunction with the choice set data in a post-hoc framework. The results for a subset of these variables are reported in this paper; differences (in the order of importance of the attributes) were found among groups. A primary finding of this study is that a student–athlete's perceived financial need has a critical impact on the institutional choice process. A second important finding is that, although “Amount of Scholarship” was determined to be the most important attribute, this result stands in stark contrast to previous studies that have investigated the institutional choice process of student–athletes.     

Relative Endurance and Physiological Responses: A Study of Individual Differences in Prepubescent Boys and Adult Men

Abstract

The reliability of individual differences in relative endurance performance and physiological response was studied in prepubescent boys (N = 21) and adult men (N = 21). Subjects were tested twice (test and retest) on a relative endurance test consisting of pedalling a bicycle ergometer for 8 minutes duration at a high initial work-rate. The work-rate averaged 103% ± 1.0% VO₂ max (mean ± S.E.) for the children and 105% ± 1.1% VO₂ max for the adults, p > .05. Except for minute 3, children and adults had similar patterns for consistency of relative endurance performance (RPM). However, in comparison to adults, children had smaller individual difference variation for both VO₂ and HR (p > .05). On the average, children had a greater proportion of total variability in VO₂ (34% vs. 17%) and HR (49% vs. 13%) due to intra-individual variability in comparison to true individual differences. Children-adult differences were attributed to maturity differences.     

The Comparison of Physiological Responses from Cycling on Friction-Braked and Electromagnetic Ergometers

Despite the apparent benefits of Title IX, the implementation of the law remains controversial, and there are divergent beliefs regarding its impact on collegiate sport. The purpose of this study was to examine how members of a university community, whose intercollegiate sport programs have changed, perceive and make sense of Title IX and the changes it incurred. Using a gendered lens (Birrell, 2000) and qualitative interviews with 13 individuals connected to the university community, insight was gained into their perceptions of Title IX and women's and men's athletic opportunities. The theme of opportunity gained and lost was central to how these individuals perceive Title IX and resonates with the liberal (feminist) concerns out of which Title IX was born.     

Between-Day Reliability and Usefulness of a Fitness Testing Battery in Youth Sport Athletes: Reference Data for Practitioners

This study aimed to evaluate the between-day reliability and usefulness of a fitness testing battery in a group of youth sport athletes. Fifty-nine youth sport athletes (age = 17.3 ± 0.7 years) undertook a fitness testing battery including the isometric mid-thigh pull, counter-movement jump, 5–40 m sprint splits, and the 5–0-5 change of direction test on two occasions separated by 7 days. Usefulness was assessed by comparing the reliability (typical error) to the smallest worthwhile change. The typical error was 5.5% for isometric mid-thigh pull and 3.8% for counter-movement jump. The typical error values were 2.7, 2.5, 2.2, 2.2, and 1.8% for the 5, 10, 20, 30, and 40 m sprint splits, and 4.1% (left) and 5.4% (right) for the 5–0-5 tests. The smallest worthwhile change ranged from 1.1 to 6.1%. All tests were identified as having “good” or “acceptable” reliability. The isometric mid-thigh pull and counter-movement jump had “good” usefulness, all other tests had “marginal” usefulness.     

The Reliability of the [Vdot]O2-HR Relation during Graded Treadmill Exercise in Prepubertal Boys and Adult Men

Abstract

When subjects make simultaneous aiming movements of the upper limbs over different distances, assimilation effects are shown; the shorter distance limb overshoots when paired with a longer distance limb. However, it is not known whether assimilation effects are due to variations in distance per se or to variations in target location. To separate the possible influences of distance and location, 60 subjects made rapid bimanual aiming movements in one of four conditions. The two different-distance groups made a 20° movement in the left hand and a 60° movement in the right hand to either the same or different target locations. The comparison groups moved 20° in each limb. Somewhat surprisingly, spatial assimilations were greater when moving different distances to the same, rather than different, target locations, which suggests interlimb differences in distance mediate assimilation effects rather than target location. Temporal assimilations were greater when distance and location were varied, but the assimilations were not related to interlimb differences in velocity, as predicted by Marteniuk and MacKenzie (1980).     

湖北男子职业足球运动员递增强度运动时最大有氧能力变化特征及评定

揭示武汉男子职业足球运动员有氧能力现状及对不同水平足球运动员有氧能力差异性的研讨,旨在为科学评定我国足球运动员专项有氧能力训练方法的实用价值及我国职业足球运动员有氧能力的现状水平提供理论参考依据.以湖北武汉职业足球俱乐部一队(2004年度中国甲级职业联赛冠军已晋升为中国超级职业联赛球队)的18名球员为研究对象,采用递增负荷跑台运动方式,测定反映最大有氧能力的相关生理指标.武汉男子职业足球运动员递增强度运动时有氧能力的测定及分析比较.武汉男子职业足球运动员递增负荷运动时测定的反映有氧能力的生理指标数值低于大量文献报道的国内、外优秀球员水平.     

Effect of Mouthguard Use on Metabolic and Cardiorespiratory Responses to Aerobic Exercise in Males

Purpose: This study investigated the physiological effects of wearing a mouthguard during submaximal treadmill exercise. Method: Twenty-four recreationally active males (M_age = 21.3 ± 2.4 years, M_height = 1.78 ± 0.06 m, M_weight = 81.9 ± 10.6 kg, M_{body mass index} = 25.8 ± 3.4 kg·m^?2) performed incremental, continuous exercise at 2, 4, 6, and 8 mph (3.2, 6.4, 9.7, 12.9 kph) for 5 min at each speed on a motor-driven treadmill on 2 separate occasions in a randomized, crossover, counterbalanced design while wearing or not wearing a self-adaptable “boil and bite” mouthguard. Respiratory rate (RR), tidal volume (V_T), ventilation (V_E), oxygen consumption (VO₂), respiratory exchange ratio (RER), and heart rate (HR) data were averaged during the last 60 s of each exercise stage; blood lactate (LA) was measured before exercise and 3 min and 10 min following exercise. Results: Repeated-measures analysis of variance revealed that mouthguard use failed to alter the response of RR, V_T, V_E, VO₂, RER, and HR to treadmill exercise (p > .05), although each variable did increase in magnitude as a result of increasing treadmill speed (p < .001). Although increasing to above resting values at both 3 min and 10 min (p < .001) after cessation of exercise, LA levels also displayed no differences with mouthguard use (p > .05). Conclusion: Despite predictable increases in respiratory, metabolic, and cardiovascular variables in response to incremental exercise, the presence of a mouthguard failed to affect the magnitude or nature of these physiological responses.     

中日竞走运动员高原训练的生理机能及运动能力的研究

10名世居高原(2260米)的中国竞走运动员和10名居平原(10m)的日本竞走运动员在多巴(2366米),作4周高原训练。高原训练后期与前期、高原与平原相比,观察到有益的代偿性改变。如运动后的恢复心率(1分至1分10秒)下降加快(13次/分降至105次/分);在负荷心率相近条件下,步速加快(3.61m/s增至3.80m/s),无氧阈速度加快(中方,3.01增至3.22;日方,2.78增至3.30m/s);左室功能有改善(SV:日男由85.4→98.1ml;C1:中男由3.10→3.28L/m~2·min);乳酸—速度曲线右移(日男由7.2→5.4mM,中男由6.2→5.6mM);缓冲系统的能力有改善(女子:BE,—4.7→0.2mM;HCO_3,18.6→25.2mM);肺通气功能有所加强(MVV:中方,108.6→113.5L/min,日方,139.8→146.6L/min)。高原训练后,下平原比赛,中日各有8名队员提高了本人最好成绩。     

运动、氧化应激与DNA损伤和修复

在分子和基因水平上对运动时氧化应激损伤、氧化应激与DNA损伤以及DNA损伤和修复等几方面关系进行探讨,旨在探讨运动疲劳和损伤发生的分子生物学基础,并对未来运动医学研究的发展趋势进行展望。     

跑台运动和营养补充对大鼠骨骼肌能量代谢酶的影响

应用长期递增负荷跑台运动造成大鼠运动性贫血状态，并对其骨骼肌内某些能量代谢酶进行观察。雄性Wistar大鼠30只，随机、筛选分为3组：对照组（10只）、递增负荷跑台运动组（简称运动组，10只）、递增负荷跑台运动＋营养补充组（简称运动＋营养组，10只）。运动组和运动＋营养组的跑台训练安排按照运动性贫血模型建立方法实施。研究表明，运动性贫血条件下，大鼠腓肠肌Mg^2＋～ATP酶、Ca^2＋-ATP酶和Ca^2＋-Mg^2＋。ATP酶指标结果显著低于正常对照组，LDH的活力显著高于对照组而低于运动＋营养组，SDH的活力则没有表现出组间差异性。运动性贫血条件下，大鼠腓肠肌内ATP酶多数会发生显著性降低、LDH表现出显著性升高，表明运动性贫血发生时伴随着骨骼肌有氧代谢酶的活性下降和有氧代谢酶的活性升高，说明此种长期递增负荷跑台运动相对提高了机体利用无氧代谢的比例，而此营养补充对此种变化影响作用不明显，此变化的内部机理尚需进一步深入研究。     

Exercise performance and cardiovascular health variables in 70-year-old male soccer players compared to endurance-trained,strength-trained and untrained age-matched men

Abstract

The aim was to investigate performance variables and indicators of cardiovascular health profile in elderly soccer players (SP, n = 11) compared to endurance-trained (ET, n = 8), strength-trained (ST, n = 7) and untrained (UT, n = 7) age-matched men. The 33 men aged 65–85 years underwent a testing protocol including measurements of cycle performance, maximal oxygen uptake (VO₂max) and body composition, and muscle fibre types and capillarisation were determined from m. vastus lateralis biopsy. In SP, time to exhaustion was longer (16.3 ± 2.0 min; P < 0.01) than in UT (+48%) and ST (+41%), but similar to ET (+1%). Fat percentage was lower (P < 0.05) in SP (–6.5% points) than UT but not ET and ST. Heart rate reserve was higher (P < 0.05) in SP (104 ± 16 bpm) than UT (+21 bpm) and ST (+24 bpm), but similar to ET (+2 bpm), whereas VO₂max was not significantly different in SP (30.2 ± 4.9 ml O₂ · min^?1 · kg^?1) compared to UT (+14%) and ST (+9%), but lower (P < 0.05) than ET (?22%). The number of capillaries per fibre was higher (P < 0.05) in SP than UT (53%) and ST (42%) but similar to ET. SP had less type IIx fibres than UT (?12% points). In conclusion, the exercise performance and cardiovascular health profile are markedly better for lifelong trained SP than for age-matched UT controls. Incremental exercise capacity and muscle aerobic capacity of SP are also superior to lifelong ST athletes and comparable to endurance athletes.     

Peak aerobic power and paddling efficiency in recreational and competitive junior male surfers

Abstract

The purpose of the present study was to measure and compare peak oxygen uptake and paddling efficiency in recreational and competitive junior male surfers. Eight male recreational surfers (mean age 18 years, s=2; mass 66.8 kg, s=13.0; height 1.75 m, s=0.10) and eight male competitive surfers (mean age 18 years, s=1; mass 68.0 kg, s=11.7; height 1.72 m, s=0.10) performed an incremental paddling test consisting of four 3-min constant load work stages followed by a ramp increase in power output of 20 W · 30 s^?1 until exhaustion. The oxygen uptake–power output relationship of the four constant load work stages and peak values obtained during the incremental paddling test were used to calculate paddling efficiency. No differences (P>0.05) were observed between the recreational and competitive surfers for peak oxygen uptake (recreational: 2.52 litres · min^?1, s=0.5; competitive: 2.66 litres · min^?1, s=0.35) or efficiency (recreational: 24%, s=3; competitive: 21%, s=4). Blood lactate concentration was significantly greater in recreational (2.4 mmol · l^?1, s=0.9) than competitive surfers (1.6 mmol · l^?1, s=0.5) during submaximal paddling. There were no differences in peak oxygen uptake or paddling efficiency between recreational and competitive surfers suggesting that peak oxygen uptake and efficiency are not sensitive to differences in surfing ability. The increase in blood lactate concentration during submaximal paddling in recreational compared with competitive surfers suggests that other determinants of paddling endurance, such as blood lactate threshold, might be better at distinguishing surfers of differing ability.     

心力变化趋势与摄氧量和心率相关性的研究

20名运动员及15名普通大学生志愿受试者在功率自行车上做递增负荷运动直至疲劳。用运动心力监测仪在记录受试者运动每个阶段的第一心音幅值，把它相对于安静时幅值增加的相应倍数定义为心力变化趋势(Cardiac Contractility Change Trend，CCCT)，并用运动心肺功能仪同时记录其摄氧量和心率，探讨运动员及普通大学生在运动及恢复状态下心肌收缩力变化趋势与摄氧量和心率的相关性。结果表明，受试者在运动及恢复阶段的心肌收缩力与摄氧量(r=0．589～0．978)和心率(r=0．739～0．986)的变化趋势之间存在着高度相关。提示，心力变化趋势指标可以作为运动员和常人临床测定心肺功能的重要指标之一，为运动医学和临床实践提供依据。     

跑台运动通过p38信号上调FNDC5激活Akt改善Ⅱ型糖尿病小鼠认知功能障碍

目的:探讨8周跑台运动对db/dbT2DM小鼠认知功能的影响及其分子机制。方法:24只8周龄db/dbT2DM小鼠和8只同龄对照m/m小鼠,将db/db小鼠随机分为:模型组(db/db)、运动干预组(db+Exe)、运动联合p38抑制剂组(db+Exe+SB203580)。db+Exe组进行8周跑台训练,db+Exe+SB203580组进行8周跑台运动联合SB203580抑制剂灌胃处理(5mg/kg,3d/W,8W)。每周定时检测小鼠的体重和空腹血糖;干预结束后,取全脑及海马组织,免疫组织化学染色观察海马不同区域的神经元损伤状态;Western Blot检测海马组织中AD样病理、神经炎症、突触可塑性、过氧化物酶体增殖物激活受体γ辅激活因子1α(PGC-1α)/Ⅲ型纤连蛋白组件包含蛋白5(FNDC5)、Akt激酶等蛋白的表达。结果显示:(1)跑台运动可明显改善db/db小鼠的认知功能障碍。(2)减轻db/db小鼠的海马神经元损伤。(3)降低海马内AD样病理、神经炎症蛋白的表达,增加突触蛋白的表达水平。(4)通过p38信号上调PGC-1α/FNDC5的表达。(5)跑台运动可激活Akt激酶,而p38抑制剂可降低跑台运动对Akt激酶的激活作用。结论:8周跑台运动可明显改善db/db小鼠的认知功能障碍,其机制可能是通过p38上调PGC-1α/FNDC5,激活Akt激酶,减弱AD病理进程,降低炎性反应,增加突触可塑性,改善其空间学习记忆能力。     

Alterations in Strength and Maximal Oxygen Uptake Consequent to Nautilus Circuit Weight Training

Abstract

The purpose of this study was to determine the effects of a Nautilus circuit weight training program on muscular strength and maximal oxygen uptake ([Vdot]O ₂ max) by comparing these effects to those produced by adhering to either a free weight (FW) strength training program or a running (R) program. Male college students who voluntarily enrolled in either a FW training class (n = 11), a Nautilus (N) circuit weight training class (n= 12), or a R conditioning class (n= 13) were subjects for this investigation. All groups participated in their respective programs 3 days per week for 10 weeks. Strength was assessed using a Cybex II isokinetic dynamometer set at an angular velocity of 60° · s ^?1 and a damping of 2. The FW group served as the control group for the assessment of [Vdot]O ₂ max changes, while the R group served as controls for the assessment of strength differences. ANCOVA revealed that the N and R groups experienced significant (p < .01) increases in [Vdot]O ₂ max expressed in L · min ^?1 (10.9 and 11.4%), ml · kg ^?1 · min ^?1 (10.8 and 11.7%), and ml · kgLBW ^?1 · min ^?1 (7.1 and 7.5%) when compared to the FW group. There were no significant differences between the N and R groups. There were no significant differences among groups in final peak torque values (after covariance), and torque at the beginning and end of the range of motion for the knee extensors, knee flexors, elbow extensors, and elbow flexors. In general, isokinetic strength values elicited by the N group compared favorably to those generated by the FW group. It was concluded that for a training period of short duration, Nautilus circuit weight training appears to be an equally effective alternative to standard free weight (strength) and aerobic (endurance) training programs for untrained individuals.     

Different types of compression clothing do not increase sub-maximal and maximal endurance performance in well-trained athletes

Abstract

Three textiles with increasing compressive surface were compared with non-compressive conventional clothing on physiological and perceptual variables during sub-maximal and maximal running. Fifteen well-trained endurance athletes (mean ± s: age 27.1 ± 4.8 years, [Vdot]O_2max 63.7 ± 4.9 ml · min^?1 · kg^?1) performed four sub-maximal (～70%[Vdot]O_2max) and maximal tests with and without different compression stockings, tights, and whole-body compression suits. Arterial lactate concentration, oxygen saturation and partial pressure, pH, oxygen uptake, and ratings of muscle soreness were recorded before, during, and after all tests. In addition, we assessed time to exhaustion. Sub-maximal (P = 0.22) and maximal oxygen uptake (P = 0.26), arterial lactate concentration (P = 0.16; 0.20), pH (P = 0.23; 0.46), oxygen saturation (P = 0.13; 0.26), and oxygen partial pressure (P = 0.09; 0.20) did not differ between the types of clothing (effect sizes = 0.00–0.45). Ratings of perceived exertion (P = 0.10; 0.15), muscle soreness (P = 0.09; 0.10) and time to exhaustion (P = 0.16) were also unaffected by the different clothing (effect sizes = 0.28–0.85). This was the first study to evaluate the effect on endurance performance of different types of compression clothing with increasing amounts of compressive surface. Overall, there were no performance benefits when using the compression garments.     

上海汉族优秀耐力运动员ACE基因I/D多态性与最大有氧能力(O_2max)的关联研究

采用PCR和breath by breath方法,对上海汉族55名优秀游泳运动员、60名优秀赛艇运动员和85名汉族普通人的ACE基因I/D多态性和V。O2max进行检测。结果显示1)上海汉族优秀游泳和赛艇运动员ACE基因的基因型和等位基因频率与上海和成都地区汉族普通人组无明显差异(P>0.05);与Caucasian人群相比,均存在非常显著性差异(P<0.0001),表现出明显的民族和地区的差异性;游泳和赛艇项目健将和一级运动员间的基因型和等位基因频率分布,存在明显差异(P<0.05);游泳运动员水平越高,II型所占比例就越高,赛艇运动员中水平越高,ID型的比例越大;2)不同基因型的游泳运动员的O2max、O2max/kg、CO2max、Emax、O2-plusemax、Wmax和Tmax等指标,均表现为II型>DD型>ID型,II型明显优于ID型(P<0.05~0.01),而赛艇运动员则表现为ID型>II型>DD型,ID明显优于DD型(P<0.05~0.01)。结果提示,游泳项目中具有II基因型或I等位基因的运动员,赛艇项目中具有ID基因型或I等位基因的运动员,可能属于运动训练敏感的高反应群体,经过多年系统科学的训练,具有成为优秀运动员的可能。ACE基因I/D多态性可作为运动训练和选材中高敏感的、非常重要的遗传标记之一。     

Physiological and biomechanical responses to walking underwater on a non-motorised treadmill: effects of different exercise intensities and depths in middle-aged healthy women

Abstract

Non-motorised underwater treadmills are commonly used in fitness activities. However, no studies have examined physiological and biomechanical responses of walking on non-motorised treadmills at different intensities and depths. Fifteen middle-aged healthy women underwent two underwater walking tests at two different depths, immersed either up to the xiphoid process (deep water) or the iliac crest (shallow water), at 100, 110, 120, 130 step-per-minute (spm). Oxygen consumption (VO₂), heart rate (HR), blood lactate concentration, perceived exertion and step length were determined. Compared to deep water, walking in shallow water exhibited, at all intensities, significantly higher VO₂ (+13.5%, on average) and HR (+8.1%, on average) responses. Water depth did not influence lactate concentration, whereas perceived exertion was higher in shallow compared to deep water, solely at 120 (+40%) and 130 (+39.4%) spm. Average step length was reduced as the intensity increased (from 100 to 130 spm), irrespective of water depth. Expressed as a percentage of maximum, average VO₂ and HR were: 64–76% of peak VO₂ and 71–90% of maximum HR, respectively at both water depths. Accordingly, this form of exercise can be included in the “vigorous” range of exercise intensity, at any of the step frequencies used in this study.