ECSS Paris 2023: CP-AP08
INTRODUCTION: Optimizing the recovery management of athletes is a crucial topic in sports because of steadily increasing training loads and competition frequency [1]. A sensitive monitoring of fatigue and recovery could reduce the risk of injury and counteract a non-functional overreaching and overtraining [2]. Therefore, the aim of this study was to validate a new field-based portable measurement based on electrostimulations of the m. quadriceps as a marker of fatigue introduced by high-intensive strength, endurance, and sprint protocols. METHODS: Twelve healthy sport students (age 22.5 ± 2.5 yrs., n=6f, 6m) participated in this cross-over study. Subjects completed three different training interventions followed by 1 week recovery. The training protocols consisted of either strength training (ST: eccentric overload squat 4x6 reps), endurance training (EN: 4x10 min running at 4mmol lactate threshold) or sprint training (SP: 4x6x5 sec all-out sprints) and were applied in a randomized counter balanced order. Low frequency fatigue (LFF) was assessed at baseline, pre- and post-exercise and after 24h and 48h using a device that measures evoked force of low- and high-frequency stimulation at the m. quadriceps (Myocene, Liège, Belgium). Changes of the low- and high-frequency force ratio (Powerdex (PD)) were compared between the different trainings and related to changes in countermovement jump height (CMJ), serum creatine kinase (CK) and delayed-onset muscle soreness (DOMS). Repeated measures ANOVA was used to detect changes of PD, CMJ and CK between interventions, measurements and gender. Reliability of PD was calculated by ICC between baseline measures. Significance level was set at p<0.05. RESULTS: PD baseline reliability was high [r=0.854]. PD changed significantly between measurements (p<0.001), while no differences between interventions (p=0.217) and gender (p=0.653) was found. PD decreased from pre to post training and ST had the strongest effect (ST: -20.2, p<0.001; SP: -10.6, p<0.001; EN: -8.0; p=0.1). Similar changes were found for CMJ (ST: -5.4 cm, p=0.029; SP: -2.7cm; EN: -0.2cm) while for CK the highest increase was found in SP (SP: +305 U/L, p=0.098; EN: +150 U/L, p=0.037; ST: 103 U/L, p=0.931). CONCLUSION: PD seems to be a reliable tool to measure the acute muscle fatigue induced by intensive training as well as the follow-up recovery, both under practical field conditions. It has to be considered that strength, endurance and repeated sprint training lead to different effects on PD which can be attributed to different mechanisms of fatigue. The highest sensitivity was shown for neuromuscular fatigue (ST) while sensitivity for muscle damage and CK activity (SP) was lower. Metabolic and cardiorespiratory fatigue (EN) seems to be less relevant for PD changes. In conclusion, PD seems to be most valid for strength and sprint training including intensive quadriceps work. 1. Hecksteden et al. (2016) 2. Thorpe et al. (2017)
Read CV Maximilian ReimannECSS Paris 2023: CP-AP08
INTRODUCTION: The performance of football goalkeepers (GKs) includes rapid changes in movement direction in response to visual stimuli. The available reactive agility tests, used to assess this ability, are sensitive enough to distinguish between field players of different performance levels [1,2]. However, there is a missing link in the reactive agility testing of football GKs. Furthermore, increasing repetitions of reactive tasks could produce fatigue, which is often neglected in the evaluation of reactive agility. Applying the novel “Football reactive agility for goalkeepers task” (FRAG), this study compares the reactive agility performance of elite youth and amateur adult GKs and analyses their changes in reaction speed with an increasing number of stimuli. METHODS: Eight elite youth (EY; 14.3±0.9 y) and eight amateur adult goalkeepers (AA; 21.6±1.3 y) underwent the reactive agility task, consisting of reaction to 8 light-based stimuli randomly displayed on 4 LED sensors (WittySEM, Microgate, Bolzano, Italy). These sensors were 2 m apart from the starting point and located at 30° and 60° angles. Participants ran and reacted to stimuli separated by 2 seconds with their hands. They performed 3 trials of the task with a 3-min rest interval. The best average reaction time of trials from the 2nd to the 7th stimulus was considered as a result of the FRAG task. Intraclass correlation (ICC) of the task with 95% CI was calculated. The Mann-Whitney U test with Cohen’s r effect size was used to compare the groups. These data are presented as median±SEM. The changes in reaction speed with an increasing number of stimuli were analysed using repeated measures ANOVA and Tukeys post hoc test. RESULTS: The ICC of the trials showed moderate to good reliability of the FRAG task (0.74-0.89). The average reaction time in the reactive agility task was shorter in the EY than in the AA group (∆–0.04±0.014 s; –1.62%; p=.028; ES = .503, large effect). Repeated measures ANOVA showed non-significant differences between reaction times to consecutive stimuli in both the EY (F [7, 159] = 1.751, p = 0.10), and the AA group (F [7, 159] = 0.98, p = 0.45). CONCLUSION: The EY GKs outperformed the AA GKs in the FRAG task. Both groups were able to maintain their level of reaction speed when responding to an increasing number of stimuli. The influence of fatigue occurred as the “U-effect” with the lowest reaction times from the 2nd to the 5th response and further increases until the last 8th response. These changes were comparable in EY and AA groups. The FRAG task provides a potential evaluation method for the reactive agility assessment of football goalkeepers. 1. Pojskic et al. (2018). Frontiers in Physiology 9(506) 2. Trajković et al. (2020). Int. J. of Env. Res. and Pub. Health 17(11) This work was supported by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic and the Slovak Academy of Sciences (No. 1/0725/23).
Read CV Filip SkalaECSS Paris 2023: CP-AP08
INTRODUCTION: Growing evidence identifies the presence, fluctuation, and persistence of mental fatigue (MF) in training and competition settings. Fencing is a sport that has seen a recent increase in scientific research. It is a typical skill-based combat sport with intermittent intensive mental demands. Exploring the nature and presence of MF in fencing provides insights to inform the practice and strategic approach of athletes and coaching staff. METHODS: A mixed-methods survey obtained 92 national-level adult practitioners perceptions of MF and understanding of its potential inducement in fencing. Thematic analysis interpreted open-text responses to specific definitions of MF. Frequency counts representing fencing-specific factors perceived to be associated with mental fatigue were reported. Perceptions of MF following fencing competition and training, and analysis of specific moments and processes were obtained using a 100mm visual analog scale. Results were displayed as mean ± SD and paired t-tests were performed to determine potential differences between perceptions of MF between moments and processes to elucidate fencing-specific MF inducement. RESULTS: Most respondents (88%) were active fencers or coaches representing all three fencing disciplines (Epee/Foil/Sabre). Participants indicated MF was more prominent after a game than training. Participants perceived MF to be associated with negative emotions (n=27), uncomfortable brain and whole-body feelings (n=24), worsened psychomotor response (n=20), disengaged thought (n=13), and sleep disturbance (n=9). In official competitions, respondents evaluated higher MF after an elimination stage game than after the pool stage (57.59±21.02 vs. 49.21±21.73; p<0.001). Sleep quality (78.26%), match environment (50.0%), and preparation duration (43.48%) were considered the most influential external inducers of MF. Higher tactical (t=6.22, p<0.001), technical (t=3.92, p<0.001), and psychological (t=3.81, p<0.001) contributions to MF were reported in relation to post-match vs. post-training. Respondents rated the cumulative execution of decision-making (57.36±23.27) and attack (51.93±25.92) as most effortful moments that induced MF during the match. The survey indicated that within a single competition bout, attention maintenance (61.80±27.11), anticipation of the opponent (53.15±24.85), and emotional regulation (52.87±25.74) contributed predominantly to perceived MF inducement. CONCLUSION: National-level fencers indicate elevated MF following competition and associate this with emotional, behavioral, and physical sensation changes. The inducement of MF in fencing combat was primarily attributed to the accumulative decision-making, attention, anticipation, and emotion regulation processes. The present findings emphasize the importance and impact of MF in fencing and highlight potential factors and interrelationships that require further applied investigation.
Read CV Chao BianECSS Paris 2023: CP-AP08