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

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.     

Energy system contribution to 400-metre and 800-metre track running

As a wide range of values has been reported for the relative energetics of 400-m and 800-m track running events, this study aimed to quantify the respective aerobic and anaerobic energy contributions to these events during track running. Sixteen trained 400-m (11 males, 5 females) and 11 trained 800-m (9 males, 2 females) athletes participated in this study. The participants performed (on separate days) a laboratory graded exercsie test and multiple race time-trials. The relative energy system contribution was calculated by multiple methods based upon measures of race VO2, accumulated oxygen deficit (AOD), blood lactate and estimated phosphocreatine degradation (lactate/PCr). The aerobic/anaerobic energy system contribution (AOD method) to the 400-m event was calculated as 41/59% (male) and 45/55% (female). For the 800-m event, an increased aerobic involvement was noted with a 60/40% (male) and 70/30% (female) respective contribution. Significant (P < 0.05) negative correlations were noted between race performance and anaerobic energy system involvement (lactate/PCr) for the male 800-m and female 400-m events (r = - 0.77 and - 0.87 respectively). These track running data compare well with previous estimates of the relative energy system contributions to the 400-m and 800-m events. Additionally, the relative importance and speed of interaction of the respective metabolic pathways has implications to training for these events.     

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

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.     

Comparison of maximal anaerobic running tests on a treadmill and track

Abstract

To develop a track version of the maximal anaerobic running test, 10 sprint runners and 12 distance runners performed the test on a treadmill and on a track. The treadmill test consisted of incremental 20-s runs with a 100-s recovery between the runs. On the track, 20-s runs were replaced by 150-m runs. To determine the blood lactate versus running velocity curve, fingertip blood samples were taken for analysis of blood lactate concentration at rest and after each run. For both the treadmill and track protocols, maximal running velocity (v _max), the velocities associated with blood lactate concentrations of 10 mmol · l^?1 ( v _10 mM) and 5 mmol · l^?1 ( v _5 mM), and the peak blood lactate concentration were determined. The results of both protocols were compared with the seasonal best 400-m runs for the sprint runners and seasonal best 1000-m time-trials for the distance runners. Maximal running velocity was significantly higher on the track (7.57 ± 0.79 m · s^?1) than on the treadmill (7.13 ± 0.75 m · s^?1), and sprint runners had significantly higher v _max, v _10 mM, and peak blood lactate concentration than distance runners (P<0.05). The Pearson product – moment correlation coefficients between the variables for the track and treadmill protocols were 0.96 (v _max), 0.82 (v _10 mM), 0.70 (v _5 mM), and 0.78 (peak blood lactate concentration) (P<0.05). In sprint runners, the velocity of the seasonal best 400-m run correlated positively with v _max in the treadmill (r = 0.90, P<0.001) and track protocols (r = 0.92, P<0.001). In distance runners, a positive correlation was observed between the velocity of the 1000-m time-trial and v _max in the treadmill (r = 0.70, P<0.01) and track protocols (r = 0.63, P<0.05). It is apparent that the results from the track protocol are related to, and in agreement with, the results of the treadmill protocol. In conclusion, the track version of the maximal anaerobic running test is a valid means of measuring different determinants of sprint running performance.     

Pacing profiles and pack running at the IAAF World Half Marathon Championships

The aim of this study was to describe the pacing profiles and packing behaviour of athletes competing in the IAAF World Half Marathon Championships. Finishing and split times were collated for 491 men and 347 women across six championships. The mean speeds for each intermediate 5 km and end 1.1 km segments were calculated, and athletes grouped according to finishing time. The best men and women largely maintained their split speeds between 5 km and 15 km, whereas slower athletes had decreased speeds from 5 km onwards. Athletes were also classified by the type of packing behaviour in which they engaged. Those who ran in packs throughout the race had smaller decreases in pace than those who did not, or who managed to do so only to 5 km. While some athletes’ reduced speeds from 15 to 20 km might have been caused by fatigue, it was also possibly a tactic to aid a fast finish that was particularly beneficial to medallists. Those athletes who ran with the same competitors throughout sped up most during the finish. Athletes are advised to identify rivals likely to have similar abilities and ambitions and run with them as part of their pre-race strategy.     

The effect of track geometry on 200- and 400-m sprint running performance

Abstract

This study looked at how the geometry of the running track affects performances in the 200- and 400 m sprint running events. Although an athletics track must be designed with two parallel straights and two curved bends, the lengths of the straights and bends are not fixed and may vary within an approved set of limits. The bend can be semi-circular or a double-curve consisting of arcs of two different radii. A mathematical model was used to calculate the effect of track geometry on race times for six different track designs; three with semi-circular bends (encompassing the extremes of the permitted designs), and the three permitted double-curve designs. The calculations revealed substantial differences among the track designs. The time difference (in the inside lane) between the fastest and slowest tracks is about 0.1 s in the 200-m race and 0.2 s in the 400-m race. The time differential between the outside and inside lanes for a double-curve track can be up to 0.08 s greater than for a standard track with semi-circular bends.     

跑节省化、无氧阈和最大摄氧量评价篮球运动员有氧能力的比较研究

以天津商务职业学院24名男篮球队员为研究对象,通过跑台测试、因子分析法等,采用跑节省化、无氧阈和最大摄氧量对篮球运动员进行评价分析。结果显示:篮球运动员跑节省化的修正值在第一公因子中载荷最大,在第二、第三公因子中跑节省化相关指标的载荷量处于相对重要位置,在第四公因子中只有跑节省化时通气量;跑节省化、无氧阈和最大摄氧量三指标在评价篮球运动员有氧耐力时,跑节省化指标优势明显。提示:跑节省化可以作为评价篮球运动员有氧耐力的首选指标。     

800米跑的项目特征及有效训练途径探索

运用献资料法对当今800米跑的项目特征、供能特点进行分析，认为800米跑是一项长时间高速度的项目，其无氧供能高达84％，在训练中应紧紧围绕无氧供能进行训练。     

Energy cost and kinematics of level,uphill and downhill running: fatigue-induced changes after a mountain ultramarathon

This study aimed to determine whether the fatigue induced by a mountain ultramarathon (MUM) led to changes in energy cost and kinematic during level and graded running. Pre- and post-race, 14 ultratrail runners ran on a level, uphill (5%) and downhill (5%) treadmill at 10 km · h^?1. Kinematic data were acquired using a photocell system. Post-race, the downhill energy cost increased by 13.1% (P < 0.001). No change was noted in level and uphill running. Duty factor and stride frequency were increased, whereas swing time, cycle time and stride length were decreased in all conditions (P < 0.05). Contact time was increased and the rate of force generation was decreased only in the uphill and downhill conditions (P < 0.05). Positive correlations were observed between performance time and the pre- to post-changes in the energy cost of level (r = 0.52, P = 0.04) and uphill running (r = 0.50, P = 0.04). MUM-induced fatigue resulted in physiological and spatiotemporal changes, though the response to fatigue varied considerably between running conditions. These changes resulted in a significant increment only in the downhill energy cost. Incorporating downhill locomotion in the training programmes of ultratrailers may help to improve performance-related physiological and biomechanical parameters.     

Aerobic Demand of Running Shoes Designed to Exploit Energy Storage and Return

This qualitative case study used tenets of critical race theory and a single focus group and individual interviews with 4 African American football athletes at a predominantly White institution of higher education (PWIHE) in an effort to bring the voices of this marginalized group into the dialogue on issues concerning institutional integrity in college sport. Institutional integrity involves an athletic program's actual commitment to the educational interests of college athletes as expressed through their structures, functions, and activities. Three themes emerged from the data: (a) there is a need for more African American role models in leadership positions within the athletic departments of these PWIHE; (b) there is a need for more financial support for athletes; and (c) African American athletes should be given a platform to voice concerns. These findings have implications for those educational stakeholders and researchers who are genuinely concerned with institutional integrity in college sport.     

女子柔道运动的供能体系与训练生化原则初探

本文通过对女子柔道运动员比赛、训练中血乳酸、血糖及血尿素氮等生化指标的测试结果,分析探讨女子柔道运动供能代谢特点及运动训练的一般生化原则。旨在对制定训练计划及掌握运动量提供理论依据。