Commentaries on Viewpoint: Physiology and fast marathons Santos-Concejero, Jordan; González-Mohíno, Fernando; González-Ravé, José María ...
Journal of applied physiology (1985),
04/2020, Volume:
128, Issue:
4
Journal Article
Los objetivos fueron i) estudiar la concordancia entre un reloj deportivo (Suunto Ambit2) y un sistema fotoeléctrico (Optogait) como instrumento referencia para medir la frecuencia de zancada (FZ) y ...la longitud de zancada (LZ); ii) observar las FZ y LZ durante la carrera al aire libre; y iii) analizar el efecto de la manipulación de la FZ en la economía de carrera monitorizada por un analizador de gases en función de las FZ encontradas en el análisis observacional. Ciento-sesenta corredores fueron analizados entre 8-14 km·h-1. El dispositivo Suunto Ambit2 concordó con el sistema de referencia en la medición de la FZ y la LZ r=0.99 (0.99-1.00); Error Típico de la Estimación=0.58 zancadas∙min-1 y 0.02m. Los corredores mantuvieron una FZ constante Coeficiente de Variación (CV)=2.4% aun cuando hubo variaciones en la velocidad (CV=6.8%), y dependieron de la LZ (CV=6.5%) durante las carreras al aire libre. Por último, los corredores mantuvieron un bajo coste de carrera con su FZ autoseleccionada (media=81.3 zancadas∙min-1), aunque un incremento hasta el 12% podría ser beneficioso cuando la velocidad varía sin detrimento en el coste de carrera. Palabras clave: Cadencia, Economía de Carrera, Velocidad, Exterior Abstract. This study aimed i) to study the agreement between a sports watch (Suunto Ambit2) with a photoelectric device (Optogait) as a reference instrument on measuring stride frequencies (SF) and stride lengths (SL); ii) to observe the stride patterns during outdoor running; and iii) to analyse the effect of SF manipulations on running economy monitored by a gas analyser and based on the observational analysis. One hundred and sixty recreational runners were analysed at speeds between 8-14 km·h-1. The Suunto Ambit2 agreed with the reference system r=0.99 (0.99-1.00); Typical Error of the Estimate=0.58 strides∙min-1 and 0.02m. Runners tended to maintain SF constant Coefficient of Variation (CV)=2.4%) during variations in speed (CV=6.8%) while relied on SL (CV=6.5%) adjustments during outdoor running. Finally, runners seemed to maintain a low running cost with their auto-selected SF (average=81.3 strides∙min-1), but an increase of up to 12% could be benefit when speed changes, without running cost detriment. Key words: Cadence, Running Economy, Velocity, Outdoor.
O objetivo deste estudo foi investigar os efeitos do estresse termico no desempenho de corrida de jogadores profissionais de futebol. Os dados de desempenho da corrida foram monitorados em vinte e ...tres jogadores da categoria masculina durante o Campeonato Brasileiro de Futebol, Serie B - 2021. Os resultados mostram que as distancias totais percorridas nos jogos, distancias percorridas em sprint (> 25,2 km/h), numero de sprints, numero de acoes em alta aceleracao (2,5-6,0 m/s.sup.2) e alta desaceleracao (-2,5 a -6 m/s.sup.2), assim como PlayerLoad, nao sofreram alteracoes significativas se comparado as condicoes de estresse termico baixo vs. moderado vs. alto. Por outro lado, os jogadores percorreram menores distancias totais em alta (i.e., 14,4-19,8 km/h) e muito alta velocidade (i.e., 19,8-25,2 km/h) em jogos realizados sob condicoes de estresse termico alto e moderado em comparacao abaixo. Diante disto, podemos concluir que os jogadores tendem a exercer menores esforcos fisicos de corrida em alta velocidade quando jogam em contexto de alto e moderado estresse termico. Portanto, a comissao tecnica pode definir estrategias para aumentar a capacidade fisica dos jogadores para enfrentar estes jogos ou organizar a equipe para que a reducao das distancias percorridas nao seja prejudicial ao estilo de jogo da equipe. Palavras-chave: GPS. Desempenho fisico. Fator contextual. Ciencia do esporte. The aim of this study was to investigate the effects of heat stress on the running performance of professional football players. Running performance data were monitored in twenty-three male players during the 2021 Brazilian Football Championship, Serie B. The results show that the total distances covered in games, distances covered in sprints (> 25.2 km/h), number of sprints, number of actions with high acceleration (2.5-6.0 m/s.sup.2), high deceleration (-2.5 to -6 m/s.sup.2), as well as PlayerLoad, did not undergo significant changes when comparing low vs. moderate vs. high heat stress conditions. On the other hand, players covered lower total distances at high (i.e., 14.4-19.8 km/h) and very high speed (i.e., 19.8-25.2 km/h) in games played under high and moderate heat stress conditions compared to low heat stress. We can conclude that players tend to exert less physical effort in high-speed running when playing in high and moderate heat-stress conditions. Therefore, the coaching staff can devise strategies to enhance the players' physical capacity to cope with these games or organize the team in a way that the reduction in distances covered does not negatively impact the team's playing style. Key words: GPS. Physical performance. Contextual factors. Sport science.
Letter to the editor Mooses, Martin; Mooses, Kerli; Haile, Diresibachew W ...
Journal of sports sciences,
01/2016, Volume:
34, Issue:
1
Journal Article
Peer reviewed
Santos-Concejero and Tucker argued in their letter to the editor that in our study the running economy in achieving superior performance was overlooked due to some methodological aspects. Having ...given the remarks of Santos-Concejero and Tucker appropriate consideration, in this letter to the editor, we argue that our paper does not downplay the influence of running economy on the determinants of the East African running phenomenon, but rather adds novel insights into the interaction between running economy, maximal oxygen uptake and performance.
Full text
Available for:
BFBNIB, FSPLJ, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The article is addressing the problem of running technique as a major factor of improving running performance. A short retrospective review showed that the main obstacle in developing a proper and ...efficient running technique was the absence of a commonly accepted concept, model of the efficient running technique, which, in its turn, did not allow the development of an efficient method of teaching. The author, based on his own studies in this field, is proposing a very specific way of solving this problem by using gravity as the major source of running movement with the rest of the factors just assisting it.
Off-road running continues to grow in popularity, with differing event categories existing, and terminologies are often used interchangeably and without precision. Trail running, mountain running, ...skyrunning, fell running, orienteering, obstacle course racing and cross-country running all take place predominantly in off-road terrain. Ultramarathon running refers to any running event over marathon distance conducted in any terrain and surface. Although some overlap may exist between these running events, mainly through the common denominator of off-road terrain, distinct features need to be recognised. As scientific interest in these activities grows, it becomes important to clarify these terms and develop a universal language for discussing these events. Similarly, off-road running athletes are generally not properly defined within the scientific literature, which makes intra- and inter-study comparisons difficult. The current position statement of the Ultra Sports Science Foundation highlights the different off-road running events and recommends clear reference to distance, surface, elevation change and altitude, type of event (continuous vs. staged), type of support, name and year of the event, governing body, and guidance on terminology. We further recommend to describe off-road running athletes by basic data, physiological determinants, training and competition characteristics in the scientific literature in order to facilitate and guide further research and practice.
Category:
Sports
Introduction/Purpose:
It is well established that elevated vertical loadrates on footstrike are a risk factor for developing running injuries. Overstriding, or increased foot and ...tibial angles at footstrike, has been theorized to increase loading rate. Thus, it is often suggested that runners shorten their stride to reduce their injury risk. However, the relationship between landing alignment and loadrates has not been well established in current literature. Thus, we aimed to investigate the relationship between sagittal plane foot angle (FA) and tibial angle (TA) with vertical loadrates in both healthy and injured forefoot (FFS) and rearfoot strike (RFS) runners. It was hypothesized that as FA and TA increased, loadrate would increase for all runners.
Methods:
This is an ongoing study with 52 healthy runners (35 RFS, 17 FFS) and 24 injured runners (14 RFS, 10 FFS) for a total of 76 runners (51 M, 25 F; age34.3±11.4 yrs). Vertical average loadrate (VALR) and vertical instantaneous loadrate (VILR) were obtained while running at 2.68 m/s on an instrumented treadmill. All runners reported 0/10 pain during the assessment. Sagittal plane FA and TA at footstrike were measured from video recording using an open-source program. Positive FA designated RFS. Positive TA was defined as ankle anterior to the knee. Between-group differences were evaluated using paired two-tailed t-tests. Correlation coefficients (r) were computed for FA and TA with VALR and VILR (p=0.05; trend: p =0.10).
Results:
Healthy RFS - FA and TA were negatively correlated with VALR and VILR. Injured RFS – There was a trend toward negative correlation between TA and both VALR and VILR. Healthy FFS – TA was negatively correlated with both loadrates. Injured FFS – There were no significant correlations. Correlation coefficients, slopes, and p values are presented in Table 1. VALR and VILR were higher in RFS vs FFS runners (56±20 vs 40±10, 69±25 vs 54±12 BW/s, p<0.01), but were not significantly different for healthy vs injured runners (52±19 vs 56±26, 63±21 vs 67±27 BW/s, p=0.4).
Conclusion:
In contrast to current thought, preliminary results suggest that increasing FA and TA at footstrike are associated with decreasing vertical loadrates. This relationship was strongest for FA in the healthy RFS runners and weakest for FA in both the healthy and injured FFS runners. With increased FA, load attenuation may be due to increased eccentric activity of the tibialis anterior as well as increased knee flexion excursion and eccentric quadriceps activity with increased TA.
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