ECSS Paris 2023: OP-AP26
INTRODUCTION: An inescapable consequence of soccer is fatigue, defined as a symptom of tiredness or weakness. This is underpinned by a complexity of physiological and psychological processes, encapsulating the interactions between performance fatigability and perceived fatigability (Enoka & Duchateau, 2016). It is of particular importance to practitioners to identify whether impairments originated from central and/or peripheral mechanisms (Taylor & Gandevia, 2008). Altered neuromuscular function from soccer match-play and training can occur immediately and last for several days and not be resolved by 72 h post-session (Hubbard et al., 2023; Brownstein et al., 2017; Thomas et al., 2017; Rampinini et al., 2011). However, no study has analysed the neuromuscular response across a soccer season. Therefore, the aim of this study was to evaluate the seasonal variation of neuromuscular function tests in response to training in professional soccer academy players. METHODS: Sixteen professional academy soccer players (age: 18 ± 1 years) performed a series of neuromuscular function tests at baseline and after a strenuous training day (pitch and gym), with retest at 24, 48, and 72 h, with further pitch and gym sessions after 48 h post-baseline. These testing weeks were completed at three time points across the season- early, mid, and late season. Neuromuscular evaluation involved maximal voluntary contractions (MVC) of the knee extensors, as well as twitch response elicited through electrical stimulation of the femoral nerve during both active contraction and rest (voluntary activation, VA; potentiated twitch force, Qtw,pot). A linear mixed modelling (LMM) was used to assess the effects of season phase (early, mid, and late) and time-points of testing on the responses to training. Participants were included in the model as a random effect, with neuromuscular measures the dependent variables. RESULTS: Variation in neuromuscular function was observed across the different time-points, with strenuous training-induced declines observed post-session in MVC force, central processes (VA), and potentiated twitch force (Qtw,pot; all P < 0.001). MVC, contractile function, and VA remained unresolved at 72 h (P = 0.001, 0.009, and 0.006 respectively). There was a fixed effect of season phase on neuromuscular function. Post-hoc analysis showed an increase in contractile function from early- to both mid- (P < 0.001) and late-season (P = 0.012) while a marked increase in central processes (VA) was shown from early to mid-season (P < 0.001) and a decrease from mid to late-season (P = 0.004). No interaction between season stage and time point of the training week was observed in MVC, Qtw,pot, or VA. CONCLUSION: This study demonstrated the impact of testing timing relative to both training and seasonal stage on the neuromuscular function of youth soccer players. This has implications for the restitution of central and peripheral mechanisms post-training, across the week, and at different stages of the season.
Read CV Ciaran DeelyECSS Paris 2023: OP-AP26
INTRODUCTION: Post-match travel is a concern for national team footballers due to physiological and physical stresses of travel, combined with the need to recover from match-play. The combination of match load [1] and travel requirements [2] are likely to have significant implications for the athlete’s fatigue, sleep, soreness and recovery. Additionally, physiological stresses of travel and the imposed time constraints may impair post-match recovery processes of athletes, particularly on return to clubs. This study explored how variations in travel demands and match-loads influence perceptual recovery, fatigue and sleep of footballers following travel after a national team match. Additionally, this study aimed to identify the influence of travel demands and the time between match kick-off and travel departure on match recovery (on Match Day +3). METHODS: Data was collated from 79 male national team footballers between October 2018 and December 2023. Total distance, high-speed distance, very high-speed distance and counts of accelerations and decelerations were measured using GPS. Post-match travel duration, direction, time zone difference, and the time between match kick off and travel departure was calculated based on travel schedules. Athletes completed a perceptual monitoring questionnaire daily from 1 day pre-match through to 3 days post-arrival from travel. The questionnaire included perceptual ratings of fatigue, soreness, sleep and stress, as well as the perceived recovery status scale [3]. Linear mixed models were built to assess the influence of match load and travel variables on each perceptual scale for the 3 days post arrival. Additional models were built using a standardised post-match timepoint of MD+3 to determine whether travel demands, and the timing of travel had influence over post-match recovery. RESULTS: Perceived recovery, fatigue, soreness, and sleep were reduced on day 1 post-travel and significantly improved for each day post-arrival (p<0.001). Higher match-loads were associated with poorer ratings on recovery, fatigue, soreness, and sleep scales (p=0.001-0.032). Athletes also reported poorer fatigue, soreness and recovery when travelling out of national teams to clubs compared to between national team matches (p<0.001). Travelling eastward was associated with poorer sleep (p=0.004). Longer periods between kick-off and travel departure were associated with poorer sleep on MD+3 (p=0.003), but had no influence on any other variable. CONCLUSION: Perceptual recovery, fatigue, sleep, and soreness following post-match travel were affected by both match load and travel demands. Athletes with greater match loads and those travelling eastward after matches are likely to be in a poorer recovery state on arrival. Additionally, departing later after a match was associated with poorer sleep due to arrival closer to MD+3 but had no impact on other recovery measures. [1] Rabbani et al. (2019) [2] Clements et al. (2023) [3] Laurent et al. (2011)
Read CV Ewan ClementsECSS Paris 2023: OP-AP26
INTRODUCTION: The previous studies examining the intensity of small-sided soccer games (SSGs) have employed heart rate, lactate and assessed the dominant energy system during SSGs. This could lead to wrong interpretation associated with the energy system during SSGs. It is not possible to evaluate the energetic contributions (EC) without determination of the oxygen uptake (VO2). In addition, the responses of the EC to SSGs could be different according to individual fitness level. Thus, the aim of this study is to assess the EC from three energy systems during SSGs, to further investigate the correlation between EC and individual aerobic performance. METHODS: One week prior to the experiment for SSGs, twelve U16 elite junior soccer players (16.4 ± 1.1 yrs, 69.9 ± 8.8 kg, 178.0 ± 6.5 cm) executed the incremental running test on treadmill (Saturn® 300/100r, GER) in order to determine the aerobic performance by means of the velocity at a fixed LA of 4 mmol/l [1]. The subjects performed 3 different SSGs, 2 vs. 2 (2SG), 4 vs. 4 (4SG) and 6 vs. 6 (6SG), separated by two or three days. 4SG and 6SG were played 4 min, while 2SG was performed 2 min. The EC was calculated based on the accumulated oxygen uptake above rest (aerobic, [WAER]), fast component of the post-exercise oxygen uptake (anaerobic alactic, [WPCr]), maximum net accumulation of blood lactate (anaerobic lactic, [WBLa]) [2] using portable spirometry (MetaMax 3B, GER) and lactate determination (BIOSEN S_line, GER). RESULTS: WAER during 2SG (69.2 ± 6.8 %) was significantly lower (p < 0.01) than 4SG (84.7 ± 3.0 %) and 6SG (87.4 ± 2.8 %), while WPCr and WBLa during 2SG (22.3 ± 3.5 % and 8.5 ± 5.1 %, respectively) was significantly greater (p < 0.05) than 4SG (12.4 ± 2.7 % and 2.9 ± 0.6 %, respectively) and 6SG (10.3 ± 2.9 % and 2.4 ± 1.0 %, respectively). WAER during 4SG was significantly lower (p < 0.05) than 6SG, while WPCr during 4SG was significantly greater (p < 0.05) than 6SG. The significant positive correlation between %WAER and velocity at 4 mmol/l was found (2SG: r=0.78, p=0.005; 4SG: r=0.66, p=0.019; 6SG: r=0.80, p=0.010) CONCLUSION: The main finding of this study is that the energy supply for all game formats with different game duration comes almost from the aerobic system with more than 70 - 90 % of total energy supply, irrespective of number of players and game duration. The share of anaerobic energy accounted for less than 15 - 30 % of total energy supply. Particularly, the glycolytic share had very small influence on energy supply with less than 3 - 10 %. In addition, the players with high level of aerobic performance could recruit the more aerobic energy system. In this context, coaches should take into account the EC of SSGs and different responses of EC according to the individual aerobic performance, when using SSGs as a tool for soccer-specific endurance training. 1. Mader et al. (1976) 2. Beneke et al. (2004)
Read CV Seonghwan OhECSS Paris 2023: OP-AP26