External and Internal Load Quantification in a semi-professional male football team

Abstract

In order to quantify the external and internal load in a Spanish First Division U-19 football team, a prospective observational study was carried out for a microcycle during the 2018/2019 season. For a 5 training sessions and 1 match, session rate of perceived exertion (sRPE) was recorded and, with accelerometry (Polar Team Pro), were analysed studying distance, sprint, running speed, decelerations and accelerations by external load, and summated heart rate zone (SHRZ) and heart rate variability (HRV) by internal load. The independence of the variables was determined and possible relationships between variables and their causality were explored. External and internal load behave independently (F=282.05; p<.001; ES=.25). Significant relationships between external and internal measures were observed: SHRZ was related con to all external variables (Distance/min, R=.845, p=.034; Sprint; r=.928, p=.008; V4/min, r=.916, p=.01; HSR/min, r=.909, p=.012; Total DF/min, r=.872, p=.023; Total AF/min, r=.921, p=.009). RRMean, con Sprint, r=-.856, p=.03; Total DF/min, r=-.943, p=.017; Total AF/min, r=-.943, p=.017). Possible causality was determined between external and internal load (R2=1.000; p=.005) and between internal load and sRPE (R2=1.000; p=.008). CE variables present a possible co-occurrence with CI variable SHRZ. The subjective IQ variable sRPE presents a possible co-occurrence with the IQ objective variables relative to HRV (RR mean, SDNN, RMSSD) and session exposure time. The training sessions, in a semi-professional context of a soccer team, do not replicate the demands of competition, this being the highest requirement of the microcycle.

Con el objetivo de analizar el comportamiento de la car-ga externa (CE) e interna (CI) en un equipo de fútbol de la Primera División Española Sub-19, se realizó un estudio prospectivo observacional durante un microciclo del perio-do competitivo durante la temporada 2018/2019. Durante 5 sesiones de entrenamiento y 1 partido se registró la per-cepción subjetiva de esfuerzo de sesión (sRPE) y, mediante acelerometría (Polar Team Pro), se analizaron las variables de CE distancia recorrida, número de sprint, velocidad de carrera, desaceleraciones y aceleraciones, y las variables de CI sumatorio de zonas de frecuencia cardíaca (SHRZ; summated heart rate zone) y variabilidad de la frecuencia cardíaca (VFC). Se determinó la independencia de las varia-bles y exploraron posibles relaciones entre las variables y su posible coocurrencia. CE y CI se comportaron de manera independiente (F=282.05; p<.001; ES=.25). Se observaron relaciones significativas entre variables de CE y CI: SHRZ se relacionó con la totalidad las variables de CE (Distancia/min, r=.845, p=.034; Sprint, r=.928, p=.008; V4/min, r=.916, p=.01; HSR/min, r=.909, p=.012; Total DF/min, r=.872, p=.023; Total AF/min, r=.921, p=.009). RRMean, con Sprint, r=-.856, p=.03; Total DF/min, r=-.943, p=.017; Total AF/min, r=-.943, p=.017). Se determinó una posible coocurrencia entre CE y CI (R2 = 1.000; p = .005) y entre CI y sRPE (R2 = 1.000; p = .008). Las variables de CE presentan una posible coocurrencia con la variable de CI SHRZ. La variable subje-tiva de CI sRPE presenta una posible coocurrencia con las variables objetivas de CI relativas a la VFC (RR mean, SDNN, RMSSD) y el tiempo de exposición de sesión. Las sesiones de entrenamiento, en un contexto semiprofesional de un equipo de fútbol, no replican las demandas de competi-ción, presentando esta la mayor exigencia del microciclo