Home literacy environment and reading comprehension in Spanish primary education     

Fernando Guzmán-Simón  Javier Gil-Flores  Alejandra Pacheco-Costa 《Journal of Research in Reading》2020,43(2):229-247

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Jump height loss as an indicator of fatigue during sprint training     

Pedro Jiménez-Reyes  Fernando Pareja-Blanco  Víctor Cuadrado-Peñafiel  Juan Párraga  Juan José González-Badillo 《Journal of sports sciences》2019,37(9):1029-1037

This study analysed the acute mechanical and metabolic responses to a sprint training session focused on maintaining maximal speed until a given speed loss was reached. Nine male high-level sprinters performed 60 m running sprints up to a 3% in speed loss with 6 min rests between sets. Mechanical responses (countermovement jump (CMJ) height and speed loss) and metabolic responses (blood lactate and ammonia concentrations) were measured pre-exercise and after each set was performed. Jump height loss showed almost perfect relationships with both lactate (r = 0.91) and ammonia (r = 0.91) concentrations. In addition, nearly perfect relationships were observed for each athlete between CMJ height loss and lactate (r = 0.93–0.99) and ammonia (r = 0.94–0.99). Very large correlations were found between speed loss and lactate (r = 0.83), and ammonia (r = 0.86) concentrations. Furthermore, close relationships were observed for each athlete between speed loss and lactate (r = 0.86–0.99), and ammonia (r = 0.88–0.98). These results suggest that the CMJ test may allow more accurate setting of training loads in sprint training sessions, by using an individualised sprint dose based on mechanical and physiological responses rather than a standard fixed number of sprints for all athletes.  相似文献   

Motor unit firing frequency of lower limb muscles during an incremental slide board skating test     

Tatiane Piucco  Rodrigo Bini  Masanori Sakaguchi  Fernando Diefenthaeler  Darren Stefanyshyn 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(4):540-551

This study investigated how the combination of workload and fatigue affected the frequency components of muscle activation and possible recruitment priority of motor units during skating to exhaustion. Ten male competitive speed skaters performed an incremental maximal test on a slide board. Activation of six muscles from the right leg was recorded throughout the test. A time-frequency analysis was performed to compute overall, high, and low frequency bands from the whole signal at 10, 40, 70, and 90% of total test time. Overall activation increased for all muscles throughout the test (p < 0.05 and ES > 0.80). There was an increase in low frequency (90 vs. 10%, p = 0.035, ES = 1.06) and a decrease in high frequency (90 vs. 10%, p = 0.009, ES = 1.38, and 90 vs. 40%, p = 0.025, ES = 1.12) components of gluteus maximus. Strong correlations were found between the maximal cadence and vastus lateralis, gluteus maximus and gluteus medius activation at the end of the test. In conclusion, the incremental skating test lead to an increase in activation of lower limb muscles, but only gluteus maximus was sensitive to changes in frequency components, probably caused by a pronounced fatigue.  相似文献   

Sprint performance and mechanical outputs computed with an iPhone app: Comparison with existing reference methods     

Natalia Romero-Franco  Pedro Jiménez-Reyes  Adrián Castaño-Zambudio  Fernando Capelo-Ramírez  Juan José Rodríguez-Juan  Jorge González-Hernández 《European Journal of Sport Science》2017,17(4):386-392

The purpose of this study was to assess validity and reliability of sprint performance outcomes measured with an iPhone application (named: MySprint) and existing field methods (i.e. timing photocells and radar gun). To do this, 12 highly trained male sprinters performed 6 maximal 40-m sprints during a single session which were simultaneously timed using 7 pairs of timing photocells, a radar gun and a newly developed iPhone app based on high-speed video recording. Several split times as well as mechanical outputs computed from the model proposed by Samozino et al. [(2015). A simple method for measuring power, force, velocity properties, and mechanical effectiveness in sprint running. Scandinavian Journal of Medicine & Science in Sports. https://doi.org/10.1111/sms.12490] were then measured by each system, and values were compared for validity and reliability purposes. First, there was an almost perfect correlation between the values of time for each split of the 40-m sprint measured with MySprint and the timing photocells (r?=?0.989–0.999, standard error of estimate?=?0.007–0.015?s, intraclass correlation coefficient (ICC)?=?1.0). Second, almost perfect associations were observed for the maximal theoretical horizontal force (F₀), the maximal theoretical velocity (V₀), the maximal power (P_max) and the mechanical effectiveness (DRF – decrease in the ratio of force over acceleration) measured with the app and the radar gun (r?=?0.974–0.999, ICC?=?0.987–1.00). Finally, when analysing the performance outputs of the six different sprints of each athlete, almost identical levels of reliability were observed as revealed by the coefficient of variation (MySprint: CV?=?0.027–0.14%; reference systems: CV?=?0.028–0.11%). Results on the present study showed that sprint performance can be evaluated in a valid and reliable way using a novel iPhone app.  相似文献