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Human Energy
Published in Eduardo Rincón-Mejía, Alejandro de las Heras, Sustainable Energy Technologies, 2017
José Antonio Aguilar Becerril, Diana Gabriela Pinedo Catalán, Paola Yazmín Jiménez Colín, Jaime Manuel Aguilar Becerril
Creatine is an energy source that contributes phosphate groups to ADP and then converts it to ATP, favoring the phosphagen pathway (ATP-CP) during high intensity physical work with intermittent recoveries, such as sprints or short explosive efforts. These movements increase work capacity and indirectly muscle mass (for athletes who require a body mass increase of 1–2 kg). The usual dose is 70 mg/kg body weight, divided into 4 or 5 doses, the first week of each month. It should be ingested with drinks rich in carbohydrates with a high glycemic index.
No diurnal variation is present in maximal fat oxidation during exercise in young healthy women: A cross-over study
Published in European Journal of Sport Science, 2023
Lidia Robles-González, Millán Aguilar-Navarro, Álvaro López-Samanes, Carlos Ruiz-Moreno, Alejandro Muñoz, David Varillas-Delgado, Jorge Gutiérrez-Hellín, Jørn W. Helge, Jonatan R. Ruiz, Francisco J. Amaro-Gahete
Endurance exercise-related metabolic processes show a diurnal variation which favours an increased performance in the afternoon compared to late night and early morning (Ayala et al., 2021). Potential explanations of this important difference could be the optimized body temperature, catecholamine release, neural activation, phosphagen metabolism, muscle buffering capacity and/or contractile muscle properties observed in response to endurance exercise in the afternoon than in the evening and/or morning (Ayala et al., 2021; Teo, Newton, & McGuigan, 2011). A series of studies have reported that MFO and Fatmax values are significantly higher in the afternoon compared with those obtained in the morning in young individuals with normal weight (Darvakh, Nikbakht, Shakerian, & Sadat Mousavian, 2014), patients with obesity (Mohebbi & Azizi, 2011) and endurance-trained athletes (Amaro-Gahete, Jurado-Fasoli, Triviño, et al., 2019; Ramírez-Maldonado et al., 2021).
Caffeine ingestion attenuates diurnal variation of lower-body ballistic performance in resistance-trained women
Published in European Journal of Sport Science, 2023
Lidia Robles-González, Mauricio Ramírez Maldonado, Juan Carlos Alcalá-Escamilla, Lucas Jurado-Fasoli, Sergio Miras-Moreno, Marcos A. Soriano, Amador García-Ramos, Jonatan R. Ruiz, Francisco J. Amaro-Gahete
Neuromuscular performance and specifically, the ability to generate strength and power during complex motor skills (e.g. throwing, lifting, jumping or running) is of paramount importance to successful athletic performance (Cormie, McGuigan, & Newton, 2011; Suchomel, Nimphius, & Stone, 2016). Researchers have previously demonstrated that stronger athletes have the ability to generate more forces and also more rapidly than their weaker counterparts, resulting in a superior sport performance (Suchomel et al., 2016). There is evidence that neuromuscular performance is reduced in the morning compared to the afternoon and evening independently of the status of training (Sedliak, Finni, Cheng, Haikarainen, & Häkkinen, 2008; Souissi et al., 2010) especially in short-term sports events which involve complex motor tasks (Atkinson & Speirs, 1998; Jasper, Häußler, Baur, Marquardt, & Hermsdörfer, 2009). The effect of the circadian rhythm on neuromuscular performance has been attributed to several physiological factors such as body temperature, hormonal status, muscle buffering capacity, phosphagen metabolism, or actin–myosin cross bridging processes (Atkinson & Reilly, 1996; Hayes, Bickerstaff, & Baker, 2010). However, most of the previous studies have solely described the effects, not exogenously manipulating their conditioning factors (e.g. using ergogenic aids) to determine variations in neuromuscular performance.
Acceleration intensity is an important contributor to the external and internal training load demands of repeated sprint exercises in soccer players
Published in Research in Sports Medicine, 2021
This study found meaningful differences in internal load variables between the protocols such as higher HR peak (ES = 0.47, small) and Time > 85% HR peak in RSE-MA compared to RSE-SA (ES = 1.11, moderate). Moreover, moderate differences were found in RPEres (ES = 1.10, moderate) and RPEmus (ES = 0.73, moderate), which underline the greater perceived cardiovascular and muscular load required during maximal accelerations (Azcárate et al., 2019). Differences in the external load demands, found in the current study, are large enough to lead to substantial changes in the physiological parameters (e.g. HR, moderate) and in players’ perceived exertion (e.g. RPE, moderate). These results support the knowledge that internal load variables (e.g. blood lactate concentration, energy cost, and HR) are affected by the acceleration intensity during intermittent running activities (Buglione & Di Prampero, 2013; Zamparo et al., 2015, 2014). A physiological explanation of such findings can be related to the higher anaerobic demands during the initial acceleration (higher during MA than SA). Such high anaerobic demands (e.g. greater utilization of ATP and PCr) due to MA compare to SA may be associated with higher HR and RPEres responses found in the current study (Jimenez-Reyes et al., 2016; Svensson & Drust, 2005). We may suppose that a higher cardiovascular involvement may be necessary to repay the initial O2 debt contracted by the anaerobic glycolysis (e.g. post-exercise oxygen consumption replenishes the phosphagen system); however, further research is needed to verify this statement since this study has not used a metabolic device. These higher anaerobic demands may also be explained by a greater muscular involvement related to higher mechanical requests during the acceleration phase. This study supports this statement since it reported a higher RPEmus, HSR, and DSL in RSE-MA. These findings may be explained considering the difference in biomechanical outputs such as higher initial force production, joint load, power, and momentum necessary to develop a MA compared to SA, which may be related to a higher neuromuscular involvement throughout the RSE (Jimenez-Reyes et al., 2016; Osgnach et al., 2010).