Author(s): RUBIO-MORALES, A., DÍAZ-GARCÍA, J., PULIDO, J.J., LÓPEZ-GAJARDO, M.A., SÁNCHEZ-OLIVA, D., PONCE-BORDÓN, J.C., Institution: UNIVERSITY OF EXTREMADURA, Country: SPAIN, Abstract-ID: 2638

Objective: Fatigability, the susceptibility to fatigue and its effects, plays a key role on sport performance. This study aimed to compare the effects of different training interventions on mental fatigability in young soccer players while investigate the mechanism(s) underlying potential training adaptations.

Methods: A randomized controlled trial including pre-testing/6-weeks intervention/post-testing was conducted with 66 young male soccer players (Mage = 15.3 ± .54 years). Participants were randomly assigned to three different groups: ECOlogical-BET (Brain Endurance Training; n=24) vs NON-ECOlogical BET (n=24) vs CONTrol (n=23). The three groups performed the same training sessions, differences were included at the last 15 min. of each session, where: ECO-BET performed a soccer-specific physically+cognitively demanding tasks vs NON-ECO BET performed a soccer-specific physically demanding task intermixed with short-bouts of cognitive tasks performed in a smartphone vs CONT performed the soccer-specific physical task. In pre- and post-testing, a) Perceived MF (Visual Analogue Scale 100-mm) and b) Soccer-specific performance (shooting performance and technical-tactical performance in Small Sided Games) were tested when fresh and after 30 min. of a sustained cognitively demanding activity (i.e., Incongruent Stroop). Potential underlying mechanisms were also evaluated: c) brain cortical activity (Emotiv EPOC X 14-channel electroencephalographic (EEG) system); d) heart Rate variability (HRV; i.e., the root Mean Square of Successive Differences (rMSSD), e) and executive functions (i.e., SOMA NPT App). Data was analyzed using Linear Mixed Models (LMM); EEG signals were analyzed using EEGLAB plugin.

Results: Both BET groups benefited perceived and performance fatigability. After the intervention, players involved in both BET groups showed lower increments in MF (p<.05) by the effects of 30 min- Stroop. ECO-BET also showed benefits on specific soccer performance when mentally fatigued in comparison with players involved in CONT (p<.05). This finding was accompanied by lower raises on rMSSD and a significant theta power decrease at frontal cortex region after engage in the Incongruent Stroop (p<.05) when compared with players involved in CONT (p<.05). This finding suggests the development of training-adaptations at the central level that are suggestive of higher mental fatigue resilience. On the contrary, the results suggest that performance on non-soccer specific executive functions was better benefited by the NON-ECO BET when compared with ECO-BET (p<.05) and CONT (p<.01.).

Conclusions: Results support previous evidence that adding cognitive tasks to physical tasks benefits the tolerance of youth soccer players to mental fatigue and its effects. This is the first study to add that these benefits may be enhanced by the inclusion of soccer-specific cognitive demands, and that this benefit may be caused by adaptations at the central nervous system.