Background: Fatigue is a process that results in a decreased ability to produce force, and which could eventually affect performance and increase the risk of injury. Force variability analysis has been proposed to describe the level of fatigue with the purpose of detecting the development of fatigue. Variability is credited to play a functional and adaptive role through which the components of a system self-organize to solve a motor problem. Non-linear tools have been applied to analyze the variability of physiological signals, revealing that the structure of motor fluctuations provides relevant information about the functional role of variability. It has been suggested that the presence of lower complexity in the variability structure could reveal a less functional and adaptative state (e.g., ageing or illness). In the last years, an increased number of studies have applied these techniques to force variability analysis in relation to fatigue.Objective: To provide an overview of the current knowledge on the use of non-linear tools on force variability as a fatigue index.Methods: Following PRISMA guidelines, a systematic search of SPORTDiscus, Scopus, Web of Science and PubMed was carried out. Studies included were: a) original studies that analyzed the effect of fatigue on humans during an action focused on force production; b) published studies with their title and abstract in English; c) studies that applied non-linear tools on a signal directly related to force production.Results: Twenty-five studies were included in this review. The relationship between fatigue and the complexity of force variability, the type of action and relative intensity, the nature of the signal and the non-linear tools used, and the methods of data acquisition and processing were identified.Conclusion: The articles reviewed suggest that fatigue leads to a decrease in complexity mostly in isometric contractions, but this is not as clear in dynamic contractions. This fatigue-induced loss of complexity seems to be a result of changes in the nervous system at the central level, albeit triggered by peripheral mechanisms. It should be noted that non-linear tools are affected by the relative intensity of contraction, non-stationarity, and the acquisition and treatment of the signal.
El objetivo del presente estudio fue aplicar el Modelo de Responsabilidad Personal y Social (MRPS, Hellison, 2011) a través del boxeo en un grupo de adolescentes en riesgo de exclusión social. Concretamente, se analizaron los efectos del programa de boxeo en la motivación hacia el ejercicio físico, las actitudes hacia la violencia, el comportamiento agresivo, la autoestima y determinados hábitos nocivos como el consumo de tabaco, alcohol y otras drogas. El programa fue aplicado durante nueves semanas, con una frecuencia de tres sesiones semanales de una hora. Se implementó una metodología de investigación cuantitativa y un diseño cuasi-experimental con un total de 11 participantes varones de 15 a 18 años (5 pertenecientes al grupo de intervención y 6 al grupo control). Todos los participantes cumplimentaron los cuestionarios seleccionados para la medición de las variables de estudio, tanto al inicio como al término del programa de boxeo. Los resultados indicaron un aumento de la motivación intrínseca hacia el ejercicio físico, y una reducción de la regulación externa e introyectada, en el grupo de intervención respecto al grupo control. Tras el programa de boxeo no se logró una reducción del consumo de tabaco, alcohol y otras drogas, pero tampoco aumentaron las actitudes hacia la violencia o el comportamiento agresivo. Los resultados indican que el boxeo puede ser un deporte apropiado para los jóvenes en riesgo de exclusión social si se enfoca desde el referente teórico adecuado. Descriptores: responsabilidad, motivación, actividad física, hábitos saludables, violencia. Abstract. The objective of this study was to apply, through boxing, the Teaching Personal and Social Responsibility Model (TPSR, Hellison, 2011) in a group of adolescents at risk of social exclusion. Concretely, the study analysed the effects of the boxing program in the following variables: motivation to physical activity, attitudes towards violence, aggressive behaviour, self-esteem and the consumption of tobacco, alcohol, and other drugs. The boxing program was applied during nine weeks, with a frequency of three 1-hour sessions per week. A quantitative research methodology and a quasi-experimental design were implemented, with a total of 11 male participants aged between 15 and 18 years (5 belonging to the intervention group and 6 to the control group). All the participants completed the selected questionnaires to measure the study variables, both at the beginning and at the end of the boxing program. The results indicated an increase of intrinsic motivation toward physical activity, and a decrease in external and introjected regulation, in the intervention group regarding the control group. There was no reduction in the consumption of tobacco, alcohol and other drugs, but neither an increase of attitudes towards violence or aggressive behaviour. The results indicate that boxing can be an appropriate sport for young people at risk of social exclusion, provided that it is based on the pertinent theoretical framework. Keywords: responsibility, motivation, physical activity, healthy habits, violence.
The aim of this study was to assess the influence of the load order used (i. e. incremental, decremental or random loads order) during the bench press throw load-velocity profile on peak velocity achieved against four different loads (20–40–60–80% of one repetition maximum [1RM]). Both intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated to assess the reliability of the measures. A repeated measures ANOVA was used to assess differences between protocols. A linear regression analysis was performed to assess the load-velocity relationships among the different protocols. Peak velocity showed good to high ICC values independently of the load used (ICC=0.83–0.92). CV scores showed good reliability (ranging between 2.2 and 6.2%). No significant differences in peak velocity attained at each load were found between the three testing protocols (p>0.05). In addition, peak velocity at each load was very large to almost perfect, correlated between protocols (r=0.790–0.920). The linear regression model showed a significant relationship between testing protocols (p<0.001; R2=0.94). In conclusion, due to some ICC scores below 0.9 and R2 below 0.95, the indistinct use of different load-order protocols to assess load-velocity relationships in the bench press throw exercise is not recommended.
Balance has been positioned as an important performance skill in sport. Differences in postural control have been found between levels of expertise. However, this statement remains unanswered in some cyclic sports. This work aimed to describe the one-leg balance performance of a sample of elite BMX riders—racing and freestyle—compared to a control group formed by recreational athletes. The center of pressure (COP) of nineteen international BMX riders (freestyle, n = 7; racing, n = 12) and twenty physically active adults was analyzed in a 30-s one-leg stance test on both legs. COP dispersion and velocity variables were analyzed. Non-linear dynamics of postural sway were evaluated through Fuzzy Entropy and Detrended Fluctuation Analysis. BMX athletes did not show differences between legs in any of the variables. The control group did show differences between the dominant and non-dominant leg in the magnitude of variability of the COP in the mediolateral axis. Group comparison revealed non-significant differences. International BMX athletes did not show better balance parameters than the control group in a one-leg stance balance task. The adaptations derived from BMX practice do not have a significant impact in one-leg stance balance performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.