Part I: Biomechanics     

T. Asai  H. Nunome  S. S. Matsubara  M. Lake 《Journal of sports sciences》2013,31(6):485-500

The purpose of this study was to determine whether the sequence of strength training before endurance training (ST/ET) is more or less effective than endurance training followed by strength training (ET/ST). Twenty‐three females and 11 males were assigned to one of three groups: ST/ET (n= 15), ET/ST (n= 15) or control (n = 4). The 7‐week training programme consisted of strength training using 10 exercises for two sets of 3–12 repetitions and running for 20–25 min at 60–90% of heart rate reserve. Maximal oxygen uptake (VO₂ max) was measured during a graded treadmill test, and muscular strength was assessed using one‐repetition maximum tests for the bench press (BP), shoulder press (SP), arm curl (AC) and leg press (LP). The VO₂ max significantly (P < 0.05) increased 6.7 and 6.2% for the ST/ET and ET/ST groups, respectively. There was no significant (P > 0.05) difference between the two experimental groups. Muscular strength significantly (P <0.05) improved by 15.2% (BP), 16.6% (SP), 17.2% (AC) and 11.9% (LP) for the ST/ET group and 19.9% (BP), 24.1% (SP), 20.9% (AC) and 14.0% (LP) for the ET/ST group. There were no significant (P > 0.05) differences between the two experimental groups for the BP, AC and LP; however, the ET/ST group increased (P < 0.05) SP strength more than the ST/ET group. In conclusion, adaptations to a combination of short‐term endurance and strength training as assessed by VO₂ max and BP, AC and LP strength appear to be independent of whether endurance training occurs prior to or following strength training.  相似文献   

Altitude and endurance training     

Heikki Rusko  Heikki Tikkanen  Juha Peltonen 《Journal of sports sciences》2013,31(10):928-945

The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (<2000-2200 m) and/or too short an altitude training period (<3-4 weeks); (2) the training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is >12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study.  相似文献   

Energy system contribution to 1500- and 3000-metre track running     

Rob Duffield  Brian Dawson  Carmel Goodman 《Journal of sports sciences》2013,31(10):993-1002

The aim of the present study was to quantify the contributions of the aerobic and anaerobic energy systems to 1500- and 3000-m track running events during all-out time-trials performed individually on a synthetic athletic track. Ten 3000-m (8 males, 2 females) and fourteen 1500-m (10 males, 4 females) trained track athletes volunteered to participate in the study. The athletes performed a graded exercise test in the laboratory and two time-trials over 1500 or 3000?m. The contributions of the energy systems were calculated by measures of race oxygen uptake, accumulated oxygen deficit (AOD), race blood lactate concentration, estimated phosphocreatine degradation and some individual muscle metabolite data. The relative aerobic energy system contribution (based on AOD measures) for the 3000?m was 86% (male) and 94% (female), while for the 1500?m it was 77% (male) and 86% (female). Estimates of anaerobic energy expenditure based on blood lactate concentrations, while not significantly different (P?>?0.05), were generally lower compared with the AOD measures. In conclusion, the results of the present study conform with some recent laboratory-based measures of energy system contributions to these events.  相似文献   

Vitamin C supplementation does not influence plasma and blood mononuclear cell IL-6 and IL-10 levels after exercise     

Antoni Aguiló  Marta Monjo  Carlos Moreno  Pau Martinez  Sonia Martínez 《Journal of sports sciences》2013,31(17):1659-1669

Abstract

The aim of this study was to determine whether the highest vitamin C supplementation associated with complete bioavailability influences the plasma and blood mononuclear cell IL-6 and IL-10 response to exercise. A double-blinded study of supplementation with vitamin C was performed. After 15 days of supplementation with vitamin C (500 mg · day^?1, n = 16) or a placebo (n = 15), participants in the study completed a 15-km run competition. Blood samples were taken before and after competition. Oxidative stress markers, antioxidants, cortisol, IL-6 and IL-10 were determined in plasma or serum. IL-6 and IL-10 protein and mRNA levels were measured in blood mononuclear cells. Although higher plasma and blood mononuclear cell vitamin C levels were observed in the supplemented group when compared with the placebo one, the two groups showed identical exercise-induced changes in all the measured parameters. Exercise induced increased IL-6 and IL-10 levels in plasma and blood mononuclear cells. IL-6 and IL-10 mRNA levels in blood mononuclear cells increased after the competition. After recovery, IL-6 mRNA returned to basal levels and IL-10 mRNA levels remained elevated. In conclusion, exercise induced increased IL-6 and IL-10 production in blood mononuclear cells. However, vitamin C supplementation did not influence IL-6 and IL-10 response to exercise.  相似文献   

Effect of shoulder angle on physiological responses during incremental peak arm crank ergometry     

Anthony S. Leicht  Warwick L. Spinks 《Journal of sports sciences》2013,31(4):443-452

Abstract

This study examined the effect of shoulder angle and gender on physiological and perceptual responses during incremental peak arm ergometry. Healthy adults (nine males, seven females) volunteered for the study and completed an incremental arm ergometry test on two separate occasions at two different shoulder angles (90° and 45°). Initial work rate was set at 16 W · min^?1 and was increased progressively until exhaustion. Cardiorespiratory and perceptual responses were recorded at the end of each minute and compared using separate three-way (position × work rate × gender) repeated-measures analyses of variance. The systematic bias of peak responses was examined using separate two-way (position × gender) analyses of variance, while reproducibility of these parameters was explored using intraclass correlation coefficients, measurement bias/ratio, and 95% ratio limits of agreement. Despite a significantly greater peak heart rate for the 45° position, cardiorespiratory and perceptual responses were similar at peak exercise for both positions. Peak values for all variables, although similar, demonstrated similar and large inter-test variability for men and women. Reduction of the shoulder joint angle to 45° did not enhance peak work rate and peak oxygen consumption during seated upper body exercise. Due to the large inter-test variability, arm ergometry should be conducted using the same seated position.  相似文献   

Effects of endurance and high-intensity swimming exercise on the redox status of adolescent male and female swimmers     

Athanasios Kabasakalis  George Tsalis  Ekaterini Zafrana  Demetrios Loupos  Vassilis Mougios 《Journal of sports sciences》2013,31(8):747-756

Abstract

Throughout adolescence, swimmers begin to carry out demanding endurance and high-intensity training sets, the effect of which on redox status is largely unknown. The aim of the present study was to investigate the effects of 2000-m continuous swimming and 6 × 50-m maximal swimming on the redox status of adolescent swimmers. Fifteen male and 15 female swimmers, aged 14–18 years, provided blood samples before, immediately after, 1 h after, and 24 h after each exercise for the determination of redox status parameters. Oxidative damage was short-lived and manifest as increases in 8-hydroxy-2?-deoxyguanosine (8-OHdG) 1 h after high-intensity exercise (39%, P < 0.001) and in malondialdehyde immediately after both exercises (65%, P < 0.001). Alterations in antioxidant parameters were sustained during recovery: reduced glutathione decreased 24 h post-exercise (11%, P = 0.001), uric acid increased gradually after high-intensity exercise (29%, P < 0.001) and bilirubin peaked 24 h post-exercise (29%, P < 0.001). Males had higher 8-OHdG (49%, P = 0.001) and uric acid (29%, P < 0.001) concentrations than females. However, females showed higher values of malondialdehyde than males immediately post-exercise (30%, P = 0.039), despite lower pre-exercise values. In conclusion, both endurance and high-intensity exercise perturbed the redox balance without inducing prolonged oxidative damage in trained adolescent male and female swimmers. These swimming training trials were not found to be detrimental to the redox homeostasis of adolescents.  相似文献   

The microcycle of inflammation and performance changes after a basketball match     

Athanasios Chatzinikolaou  Dimitrios Draganidis  Alexandra Avloniti  Alexandros Karipidis  Athanasios Z Jamurtas  Chrysanthi L Skevaki 《Journal of sports sciences》2013,31(9):870-882

Abstract

Basketball incorporates intense eccentric muscle activity that induces muscle microtrauma and an inflammatory response. This study investigated time-dependent inflammatory and performance responses during a weekly microcycle after a basketball match. Twenty elite-standard players underwent a trial that comprised a match followed by a 6-day simulated in-season microcycle. The trial was preceded by a control condition that did not have a match. Blood sampling and tests of maximal-intensity exercise performance and muscle damage occurred before each condition, immediately after the match and daily thereafter for 6 consecutive days. The match induced marked increases in heart rate, lactate, ammonia, glucose, non-esterified fatty acids and triglycerides. Performance deteriorated for 24–48 h after the match, whereas knee flexor and extensor soreness increased for 48 and 24 h post-match, respectively. Inflammatory (leukocytes, C-reactive protein, creatine kinase activity, adhesion molecules, cortisol, uric acid and cytokines) and oxidative stress (malondialdehyde, protein carbonyls, oxidised glutathione, antioxidant capacity, catalase and glutathione peroxidase) markers increased for ~24 h and subsided thereafter. Reduced glutathione declined for 24 h after exercise. These results suggest that a basketball match elicits moderate and relatively brief (~24–48 h) inflammatory responses, is associated with marked but short-lived performance deterioration, but is less stressful than other intermittent-type sports.  相似文献   

The Estimation of [Vdot]O2max from Maximal and Sub-Maximal Measurements in Males,Age 10–39     

Henry J. Montoye  Thomas Ayen  Richard A. Washburn 《Research quarterly for exercise and sport》2013,84(3):250-253

Abstract

The purpose of this study was to assess the relationship between physiological and anthropometrical variables and 15-km time trial (TT) cycling performance time. Twenty-two competitive cyclists averaged 59.7 ml · kg^–1 · min^–1 for maximal oxygen consumption ([Vdot]O_2max), 42.8 ml · kg^–1 · min^–1 for anaerobic threshold (AT), and 23.5 min for the 15 km TT race. The relationship between [Vdot]O_2max and cycling performance time was r = – 0.68, (p < .01) while the correlation between AT and performance time was r = – 0.93, (p <.01). Applying stepwise multiple regression analysis, the two-variable model of the AT and the body circumference ratio, thigh+calf:arm+chest, was found to correlate highly with cycling performance time (r =0.966). It was concluded that the successful cyclists are characterized by the ability to consume large amounts of oxygen prior to ventilatory changes associated with the anaerobic threshold as well as a larger lower to upper body circumference ratio which may favorably decrease wind resistance while cycling.  相似文献   

The effect of stress inoculation training on self‐reported stress,observer's rating of stress,heart rate and gymnastics performance     

Roger D. Mace  Douglas Carroll 《Journal of sports sciences》2013,31(3):257-266

Eighteen volunteer female subjects received preliminary instruction in a simple gymnastics bench sequence. They were then given a pre‐intervention test on a bench at ground level. Self‐reported distress, an independent observer's ratings of distress and heart rates were monitored immediately prior to performance of the sequence. Performances were also videotaped and formally scored by a qualified gymnastics judge. Subjects were then randomly assigned to a stress inoculation training group or a ‘no stress management’ training control group. Stress inoculation group subjects then received seven sessions of training in relaxation, imagery and making self‐statements in order to develop a set of coping skills. Control group subjects also received seven training sessions during which they practised a series of coordination exercises, but no psychological stress management training was given to this group.

All subjects were then re‐tested on the bench sequence but this time at a height of 1.52 m. Self‐reported stress, observer's ratings of distress and heart rate were recorded as before. Performance was again videotaped for scoring. The stress inoculation group reported significantly less stress prior to the test on the elevated beam than the control group. However, the groups did not differ in terms of heart rate. Further, the stress inoculation group performed reliably better than the control group on the elevated bench.  相似文献   

Influence of aerobic versus anaerobic exercise on the relationship between reproductive hormones in men     

A.C. Hackney  M.C. Premo  R.G. McMurray 《Journal of sports sciences》2013,31(4):305-311

This study examined the effects of equal anaerobic and aerobic total work outputs on the relationship between reproductive hormones in men. Nine subjects performed three randomized trials on separate days: (1) 1 h period of rest (control), (2) 1 h continuous aerobic exercise (65% VO₂ max), and (3) 1 h intermittent anaerobic exercise (which included 2 min exercise periods at 110% FO₂ max). The total work output of the aerobic and anaerobic trials were equated. For the 8 h after each experimental trial, blood samples were collected hourly and analysed for testosterone, luteinizing hormone (LH), follicle‐stimulating hormone (FSH), prolactin and cortisol. Diet, physical activity and circadian influences were all controlled. Compared with the control, the aerobic and anaerobic trials significantly (P < 0.05) elevated testosterone, prolactin and cortisol; however, these changes were transient and returned to control levels within 1–2 h of recovery. Neither exercise produced significant (P > 0.05) changes from control for LH and FSH. The area under the hormonal response curves (AUC) was calculated for the 8‐h recovery period. The testosterone and LH AUC results did not differ (P > 0.05) among the trials (the FSH AUC was not calculated). The prolactin AUC for the aerobic and anaerobic trials were greater (P < 0.01) than the control trial. The cortisol AUC for the anaerobic trial was greater than both the control and aerobic trials (P < 0.05), but the aerobic and control trials did not differ from one another. Correlation analysis among the AUC results within each trial showed testosterone and LH to be significantly related during the control (r = 0.723, P < 0.05) and aerobic (r = 0.801, P < 0.01) trials, but not so during the anaerobic trial (r = 0.430, P > 0.05). No other significant correlations were found. The present findings suggest the relationship between testosterone and LH is affected by anaerobic exercise but not aerobic exercise. However, the effect of anaerobic exercise upon the testosterone‐LH relationship did not seem related to the concurrently induced prolactin or cortisol changes. Anaerobic exercise may produce some degree of temporary alteration within the testosterone‐LH component of the hypothalamic‐pituitary‐gonadal axis; however, the mechanism for this phenomenon remains unclear.  相似文献