The relationship between age and running time in elite marathoners is U-shaped

GeroScience - Several investigations have demonstrated that running performance gradually decreases with age by using runners >25 years grouped in 5-year age brackets. The aim of this study...     

Does cost of running depend on speed?

Abstract Two series of experiments were carried out with similar techniques to assess the gross cost of running (CR), i.e. the ratio between O₂ demand and speed. The two groups of male subjects differed in average maximal O₂ uptake and variation coefficient (V̇O₂ max = 70.9 ± 4.7 ml O₂ • min ^–1 • kg^–1 , VC = 6.6%; and 61.1±10.1 ml O₂ • min^–1 • kg^–1, VC =16.5%). In the first series the O² demand (VO₂, mlO₂ • min^–1 • kg^–1) was measured in the final 30 s of 4-min runs at 7 treadmill speeds (V, 166.7 to 366.7 m • min^–1) in 12 well trained male marathon runners. After having added the anaerobic component of O₂ demand, a mean linear regression was computed: VO₂ = -11.5±4.0 + 0.232±0.018 * V , R² = 0.992±0.004 (mean ± standard deviation). The intercepts (i.e. the apparent VO₂ corresponding to V=0 or VO_{2 V0}) were linearly related to the slopes (ΔVO₂/ΔV; R=-0.71, p=0.0007). CR increased on average from 0.163±0.013 to 0.198±0.010 mlO₂ • kg^–1 • m^–1 in the range of 166.7–333.3 m • min^–1. The percent increase ranked from 10.1% to 37.4%. In the second series of experiments (18 subjects), VO_{2 V0} was inversely related to VO₂ max while the opposite was true for ΔVO₂/ΔV. Subjects with the lowest (VO₂ max) presented positive values of VO_{2 V0}. In conclusion, the widespread idea that gross CR is speed independent does not apply to all distance runners. Therefore, gross CR should be measured at race speed whenever gross CR is utilized to predict running performance.     

High‐sensitivity troponin T in marathon runners,marathon runners with heart disease and collapsed marathon runners

Endurance exercise is an established cause of cardiac troponin (cTn) elevation, of further interest is whether this rise represents clinical significance. This study compared cTnT rise in three cohorts of marathon runners using a high‐sensitivity assay; control runners, those with known heart disease and runners who collapsed at the finish line. Control runners (n = 126) and runners with heart disease (n = 12) were prospectively recruited with cTnT levels measured pre‐race and at race completion. Collapsed runners (n = 15) were retrospectively recruited. A mixed model ANCOVA was used to compare the three groups. Pre‐race median cTnT for the control group and heart disease groups was 3.9 ng/L (IQR 3.1 ng/L) and 4.1 ng/L (IQR 3.4 ng/L). Post‐race values for the three groups were control 45.6 ng/L (IQR 42.5 ng/L), heart disease 41.2 ng/L (IQR 36.1 ng/L), and collapsed 41.9 ng/L (IQR 57.8 ng/L). Post‐race cTnT and cTnT change were significantly correlated with pre‐race cTnT within the control group (r = 0.38 and 0.30, P < 0.01). There was no difference in post‐race cTnT (adjusted for pre‐race cTnT) between the three groups. None of the runners reported symptoms suggestive of acute myocardial infarction on follow‐up. These results demonstrate that marathon running is associated with an asymptomatic cTnT rise for all runners, and this rise is significantly correlated to baseline cTnT levels, in addition, marathon runners with pre‐existing cardiac pathology or who collapse at the finish line do not exhibit an increased cTnT rise compared to healthy runners.     

二维斑点追踪超声心动图对业余马拉松运动员右心室收缩功能的评估

目的应用二维斑点追踪超声心动图评估业余马拉松运动员右心室收缩功能。 方法2019年1月至2020年12月,在杭州地区招募业余马拉松运动员88例,根据参加马拉松运动时限分为短期组（≤6个月）、中长期组（6个月~3年）和长期组（＞3年）;另选取同一时期在杭州师范大学附属医院体检的健康受试者30例为对照组。应用常规超声心动图测量右心室流出道内径（RVOT）、右心室基底段内径（RVD_basal）及中间段内径（RVD_mid）、右心室剑突下切面室壁厚度（RVWT）、三尖瓣环收缩期位移（TAPSE）、三尖瓣环收缩期速度（S′）、右心室心肌做功指数（RIMP）和肺动脉收缩压（SPAP）,应用二维斑点追踪技术获得右心室整体纵向应变（GLS）和游离壁纵向应变（RVLS）。对业余马拉松运动员在完成全程马拉松运动前、运动后1 h和运动后第4天分别行超声心动图检查。对4组受试者的常规超声心动图参数及右心室应变参数进行比较,并分析马拉松运动员运动前GLS、RVLS与SPAP的相关性。 结果短期组TAPSE高于对照组,差异有统计学意义（P＜0.05）;中长期组RVOT、RVD_basal、RVD_mid、RVWT均高于短期组,差异有统计学意义（P均＜0.05）;长期组RVOT、RVD_basal、RVD_mid均高于中长期组,差异有统计学意义（P均＜0.05）;长期组RVWT、RIMP、SPAP高于对照组,差异有统计学意义（P均＜0.01）。短期组RVLS高于对照组,差异有统计学意义（P＜0.05）;长期组GLS低于短期组及对照组,差异有统计学意义（P均＜0.05）。运动后1 h及第4天中长期组GLS、RVLS低于短期组,差异均有统计学意义（Z=2.416、-2.579,Z=2.254、-3.005,P均＜0.05）,长期组GLS、RVLS亦低于短期组,且差异均有统计学意义（Z=-2.858、-2.825,Z=-3.524、-4.073,P均＜0.05）。组内运动前后比较,中长期组、长期组运动后1 h GLS均低于运动前,差异有统计学意义（Z=-1.968、-1.966,P均＜0.05）;短期组、中长期组和长期组运动后1 h RVLS均低于运动前,差异有统计学意义（Z=2.011、-2.258、-2.026,P均＜0.05）。相关性分析表明,运动员组运动前的GLS、RVLS与SPAP存在相关性（r=0.378、0.325,P均＜0.01）。 结论业余马拉松运动员早期右心室游离壁纵向收缩功能增强,随着运动年限增加右心室整体纵向收缩功能减低;全程马拉松运动后右心室游离壁收缩功能短暂下降。     

Physiological differences between black and white runners during a treadmill marathon

Summary To determine why black distance runners currently out-perform white distance runners in South Africa, we measured maximum oxygen consumption (V _{O 2max}), maximum workload during a V _{O 2max} test (L _max), ventilation threshold (V _Thr), running economy, inspiratory ventilation (V _I), tidal volume (V _T), breathing frequency (f) and respiratory exchange ratio (RER) in sub-elite black and white runners matched for best standard 42.2 km marathon times. During maximal treadmill testing, the black runners achieved a significantly lower (P<0.05) L _max (17 km h^–1, 2% grade, vs 17 km h^–1, 4% grade) and V _I max (6.21 vs 6.821 kg^–2/3 min^–1), which was the result of a lower V _T (101 vs 119 ml kg^–2/3 breath^–1) as f _max was the same in both groups. The lower V _T in the black runners was probably due to their smaller body size. The V _Thr occurred at a higher percentage V _{O 2max} in black than in white runners (82.7%, SD 7.7% vs 75.6%, SD 6.2% respectively) but there were no differences in the V _{O 2max}. However, during a 42.2-km marathon run on a treadmill, the black athletes ran at the higher percentage V _{O 2max} (76%, SD 7.9% vs 68%, SD 5.3%), RER (0.96, SD 0.07 vs 0.91, SD 0.04) and f (56 breaths min^–1, SD 11 vs 47 breaths min^–1, SD 10), and at lower V _T (78 ml kg^–2/3 breath^–1, SD 15 vs 85 ml kg^–2/3 breath^–1, SD 19). The combination of higher f and lower V _T resulted in an identical V _I. Blood lactate levels were lower in black than in white runners (1.3 mmol l^–1, SD 0.6 vs 1.59 mmol l^–1, SD 0.2 respectively). It appeared that the only physiological difference that may account for the superior performance of the black runners was their ability to run at a higher percentage V _{O 2max} max during competition than white runners.     

β-endorphin and adrenocorticotropic hormone production during marathon and incremental exercise

Summary To evaluate the increases in concentration of -endorphin and adrenocorticotropic hormone (ACTH) 16 healthy athletes, well-trained for endurance exercise, volunteered for an exhausting incremental graded treadmill exercise and a marathon run. Maximum oxygen uptake was determined during the treadmill exercise. Venous blood samples were drawn before and after exercise, and at 30, 60 and 120 min during the recovery phase. For the marathon race venous blood was collected before, after 1 and 2 h of running and at the end, as well as at 0.5, 1, 2 and 24 h during the recovery phase. Lactate concentration, heart rate and perceived exertion were also determined at all points of blood collection. Both types of exercise led to significant increases in concentration of -endorphin and ACTH of similar magnitude, with -endorphin tending to be higher after the marathon run. The decrease of both was slower during the recovery from the marathon than after the incremental test. Concentrations of both hormones increased exponentially during the marathon run. Positive correlations between -endorphin and ACTH concentrations were determined at the end of both runs. It was found that incremental exhausting and prolonged exhausting endurance exercise such as marathon running induced an increase of similar magnitude in both -endorphin and ACTH concentration.     

L’activité mentale du coureur

The cognitive orientations of runners consist mainly in associative thoughts (bodily sensations and attending to physical symptoms) and in dissociative thoughts (distraction from bodily sensations). In a recent study investigating runner's cognitions during a marathon, Stevinson and Biddle (1998) have quantified the proportion of the race during which the participants were engaged in four different categories of thoughts: associative with inward monitoring (bodily sensations), associative with outward monitoring (pace of the race), dissociative with outward focus (people and landscape) and dissociative with inward focus (daydreams). Inward monitoring seems to be the most frequent category of thoughts for any runner, whatever the level of expertise. Inward focusing (daydreams, preoccupations) is associated with a lower level of performance whether outward focusing, together with inward monitoring, seems to partly protect runners from “hitting the wall”.     

Changes in acid-base status of marathon runners during an incremental field test

Summary Four top-class runners who regularly performed marathon and long-distance races participated in this study. They performed a graded field test on an artificial running track within a few weeks of a competitive marathon. The test consisted of five separate bouts of running. Each period lasted 6 min with an intervening 2-min rest bout during which arterialized capillary blood samples were taken. Blood was analysed for pH, partial pressure of oxygen and carbon dioxide (P0₂ and PCO₂) and lactate concentration ([la^–]_b). The values of base excess (BE) and bicarbonate concentration ([HCO₃ ^–]) were calculated. The exercise intensity during the test was regulated by the runners themselves. The subjects were asked to perform the first bout of running at a constant heart rate f _c which was 50 beats · min^–1 below their own maximal f _c. Every subsequent bout, each of which lasted 6 min, was performed with an increment of 10 beats · min^–1 as the target f _c. Thus the last, the fifth run, was planned to be performed with fc amounting to 10 beats · min^–1 less than their maximal f _c. The results from these runners showed that the blood pH changed very little in the bouts performed at a running speed below 100% of mean marathon velocity ( _m). However, once _mwas exceeded, there were marked changes in acid-base status. In the bouts performed at a velocity above the _mthere was a marked increase in [la^–]_b and a significant decrease in pH, [HCO₃ ^–], BE and PCO₂. The average marathon velocity ( _m) was 18.46 (SD 0.32) km·h^–1. The [la^–]_b at a mean running velocity of 97.1 (SD 0.8) % of _mwas 2.33 (SD 1.33) mmol ·l^–1 which, compared with a value at rest of 1.50 (SD 0.60) mmol·l^–1, was not significantly higher. However, when running velocity exceeded the vm by only 3.6 (SD 1.9) %, the [la^–]b increased to 6.94 (SD 2.48) mmol·l-1 (P<0.05 vs rest). We concluded from our study that the highest running velocity at which the blood pH still remained constant in relation to the value at rest and the speed of the run at which [la^–]_b began to increase significantly above the value at rest is a sensitive indicator of capacity for marathon running.     

Transient Dissociation of Bone Metabolism Induced by High Performance Exercise: A Study in Elite Marathon Runners

Bone metabolism parameters were studied in 18 elite marathon runners (11 men and 7 women) who participated in the Marathon World Cup held at San Sebastian, Spain in 1993. Measurements were made before the race, immediately after the race, and 24 hours after the race. The most interesting finding was increased alkaline phosphatase (P < 0.0001) and decreased tartrate-resistant acid phosphatase (P= 0.0035), which suggests that exercise produced uncoupling of the bone cell metabolism. Serum calcium corrected for proteins did not increase with exercise and at the end of the race there was a negative correlation between cortisol, which was significantly higher (P < 0.0001), and corrected serum calcium (r = 0.53, P= 0.026) that was not present at baseline. Running time showed a significant negative correlation with baseline serum cortisol (r =−0.67, P= 0.0015) and a significant positive correlation with body mass index (r = 0.53, P= 0.0207). The increase in alkaline phosphatase persisted 24 hours after the race, which suggests that exercise produced an intense and sustained effect on osteogenic capacity. Received: 12 December 1996 / Accepted: 22 September 1998