Previous studies on HR recovery (HRR) measures have utilized the supine and the seated postures. However, the most common recovery mode in sport and clinical settings after running exercise is active walking. The aim of the current study was to examine the reliability of HR measures during walking (4 km · h(-1)) before and following a maximal test. Twelve endurance athletes performed an incremental running test on 2 days separated by 48 h. Absolute (coefficient of variation, CV, %) and relative [Intraclass correlation coefficient, (ICC)] reliability of time domain and non-linear measures of HR variability (HRV) from 3 min recordings, and HRR parameters over 5 min were assessed. Moderate to very high reliability was identified for most HRV indices with short-term components of time domain and non-linear HRV measures demonstrating the greatest reliability before (CV: 12-22%; ICC: 0.73-0.92) and after exercise (CV: 14-32%; ICC: 0.78-0.91). Most HRR indices and parameters of HRR kinetics demonstrated high to very high reliability with HR values at a given point and the asymptotic value of HR being the most reliable (CV: 2.5-10.6%; ICC: 0.81-0.97). These findings demonstrate these measures as reliable tools for the assessment of autonomic control of HR during walking before and after maximal efforts.

In order to understand the effect of endurance running on inflammation, it is necessary to quantify the extent to which acute and chronic running affects inflammatory mediators. The aim of this study was to summarize the literature on the effects of endurance running on inflammation mediators. Electronic searches were conducted on PubMED and Science Direct with no limits of date and language of publication. Randomized controlled trials (RCTs) and non-randomized controlled trials (NRCTs) investigating the acute and chronic effects of running on inflammation markers in runners were reviewed by two researchers for eligibility. The modified Downs and Black checklist for the assesssments of the methodological quality of studies was subsequently used. Fifty-one studies were finally included. There were no studies with elite athletes. Only two studies were chronic interventions. Results revealed that acute and chronic endurance running may affect anti- and pro-inflammatory markers but methodological differences between studies do not allow comparisons or generalization of the results. The information provided in this systematic review would help practitioners for better designing further studies while providing reference values for a better understanding of inflammatory responses after different running events. Further longitudinal studies are needed to identify the influence of training load parameters on inflammatory markers in runners of different levels and training background.

PurposeGiven the co-existence of post-activation potentiation (PAP) and fatigue within muscle, it is not known whether PAP could influence performance and pacing during distance running by moderating fatigue. The aim of this study was to assess the influence of PAP on pacing, jumping and other physiological measures during a self-paced 30 km trial.MethodsEleven male endurance-trained runners (half-marathon runners) volunteered to participate in this study. Runners participated in a multi-stage 30 km trial. Before the trial started, determination of baseline blood lactate (bLa) and countermovement jump (CMJ) height was performed. The self-paced 30 km trial consisted of 6 × 5 km splits. At the end of each 5 km split (60 s break), data on time to complete the split, CMJ height, Rating of Perceived Exertion (RPE) and blood lactate were collected while heart rate was continuously monitored.ResultsThere was a significant decrease in speed (e.g. positive pacing strategy after the 4th split, p<0.05) with a progressive increase in RPE throughout the trial. Compared with baseline, CMJ height was significantly (p<0.05) greater than baseline and was maintained until the end of the trial with an increase after the 5th split, concomitant with a significant reduction in speed and an increase in RPE. Significant correlations were found between ΔCMJ and ΔSPEED (r = 0.77 to 0.87, p<0.05) at different time points as well as between RPE and speed (r = -0.61 to -0.82, p<0.05).ConclusionOur results indicates that fatigue and potentiation co-exist during long lasting endurance events, and that the observed increase in jump performance towards the end of the trial could be reflecting a greater potentiation potentially perhaps counteracting the effects of fatigue and preventing further reductions in speed.

RESUMOTestes incrementais em esteira rolante são muito utilizados para prescrição de treinamentos, havendo alterações fisiológicas e cinemáticas devido à natureza de incremento da intensidade do exercício. Contudo, a antropometria é um fator que não apresenta consenso na literatura. [GLI] antes do teste incremental (1,94 ± 0,4mmol/L e 94,3 ± 7mg/dL, respectivamente) foram significantemente menores que os valores encontrados após o teste incremental (9,51 ± 2,7mmol/L e 126 ± 16mg/ dL, respectivamente). Além disso, verificou-se aumento significante e gradativo da AP e FP ao longo do teste incremental. Correlações inversas e significantes (p < 0,05) foram encontradas entre a [LAC] e altura, massa corporal e o nível de treinamento dos voluntários. Conclui-se que a execução do teste incremental altera parâmetros cinemáticos (pela necessidade de deslocamento mais rápido) e fisiológicos (processo de fadiga muscular, em decorrência do aumento da velocidade). Além disso, voluntários menores e mais leves podem apresentar maiores concentrações de metabólitos.Palavras-chave: fadiga muscular, corrida, teste incremental, cinemática. ABSTRACTIncremental treadmill tests are widely used for prescription of aerobic and anaerobic training. Physiological and kinematics parameters are changed by the progressive nature of this activity. However, there is no consensus on how anthropometric characteristics may affect the incremental test performance. Therefore, the aims of this study were (1) to verify the effects of the incremental treadmill test on the blood lactate concentration ([LAC]), glucose concentration ([GLU]), step frequency (SF) and step length (SL), and (2) to correlate anthropometric data (body mass, height, %body fat) to changes in [LAC] and [GLU]. Thirteen healthy males volunteered to this study and performed an incremental running test on a treadmill (start: 8 km/h, with progressive increases [1 km/h] at each three minute until exhaustion).[LAC] and [GLU] were registered before and 3 min after the incremental test performance. SF and SL were registered for each running speed by digital images at the sagital plane. As results, we verified that [LAC] and [GLU] before the incremental test (1.94 ± 0.4 mmol/L and 94.3 ± 7 mg/dL, respectively) were significantly lower (p < 0.05) than after the incremental test (9.51 ± 2.7 mmol/L and 126 ± 16. mg/dL, respectively). In addition, SF and SL presented significant increase (p < 0.05) throughout the incremental test.[LAC] presented inverse and significant correlations (p < 0.05) to height and body mass. Thus, an incremental treadmill running test affects kinematic (SF and SL) and physiological conditions (muscular fatigue, as consequence of the speed increase). Besides this, shorter and lighter subjects may present higher metabolite concentrations after this type of test.

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Knowing running speed, particularly by means of easy-to-apply tests and low cost, is important for the definition of the race strategy and the most appropriate training throughout the preparation period. The aim was to compare the agreement and reproducibility of critical velocity (CV), anaerobic threshold (AT), and the simulated time trial on the track for the determination of the running speed in a 10-km race in amateur runners. A cross-sectional study was conducted with 34 runners of both genders aged 42.4±11.0 years. We measured their CV, assessed their body composition and AT. Participants performed also a simulated time trial on a 10-km running track and an official 10-km race. The delta of the comparisons and the standard error of estimate between the running velocities determined by the CV, AT, and the simulated time trial on the track ranged from 0.55 to -0.79 km/h and 0.14 to 0.59 km/h, respectively. Furthermore, CV and AT were compared to the 10-km running speed. Good agreement and reproducibility were observed between the velocities determined by the CV, AT, and the simulated time trial on the track with the real-time of a 10-km official race.