Showing papers by "Stefano D'Ottavio published in 2019"

The Effects of Long Sprint Ability-Oriented Small-Sided Games Using Different Ratios of Players to Pitch Area on Internal and External Load in Soccer Players.

Abstract: Purpose: The aim of this study was to examine the internal and external load imposed by long sprint ability–oriented small-sided games (SSG) using different players to pitch area ratio (densities) in soccer players. Methods: A total of 19 professional soccer players from the same soccer club (age = 17.1 [0.3] y, height = 1.76 [0.69] m, and body mass = 69.7 [9.4] kg) participated in this study. Players performed 4 × 30-second (150 s recovery) all-out 1v1 SSG considering 300, 200, and 100 m2 per player (48 h apart). Players’ external load was tracked with global positioning technology (20 Hz). Heart rate, blood lactate concentration (BLc), and rating of perceived exertion characterized players’ internal load. Peak BLc was assessed with a 30-second all-out test on a nonmotorized treadmill (NMT). Results: SSG300 produced higher BLc than SSG200 (moderate) and SSG100 (large). The SSG300, SSG200, and SSG100 BLc were 97.8% (34.8%), trivial; 74.7% (24.9%), moderate; and 43.4% (15.7%), large, of the NMT30s peak BLc, respectively. Players covered more distance at high intensity during the SSG300 than in other SSG conditions (huge to very large differences). High-intensity deceleration distance was largely lower in SSG200 than in SSG300. SSG100 elicit very large to huge and large to very large lower external load values than SSG300 and SSG200, respectively. Conclusions: The main finding of this study showed an inverse association between ball drill density and internal/external loads in long sprint ability-oriented SSG. The SSG300 attested to provide BLc closer to individual maximal, and thus, satisfying the all-out construct assumed for long sprint ability development. Further studies using the SSG300 as training intervention and/or investigating other different SSG formats using the same density are warranted.

Salivary Metabolome and Soccer Match: Challenges for Understanding Exercise induced Changes.

Abstract: Saliva samples of seventeen soccer players were analyzed by nuclear magnetic resonance before and after an official match. Two different ways of normalizing data are discussed, using total proteins and total metabolite concentrations. Changes in markers related to energy, hydration status, amino acids and other compounds were found. The limits and advantages of using saliva to define the systemic responses to exercise are examined, both in terms of data normalization and interpretation, and the time that the effect lasts in this biofluid, which is shorter to that commonly observed in blood. The heterogeneous nature and different timing of the exercise developed by players also plays an important role in the metabolic changes that can be measured. Our work focuses mainly on three different aspects: The effect that time sampling has on the observed effect, the type of normalization that is necessary to perform in order to cope with changes in water content, and the metabolic response that can be observed using saliva.

Body Composition in Children and Adolescents Residing in Southern Europe: Prevalence of Overweight and Obesity According to Different International References.

Abstract: The objective was to analyze body composition in children and adolescents of Southern Europe to identify prevalence of overweight and obesity. This investigation involved 512 girls and 488 boys between 7-to 19-years. Variables evaluated were Body Mass Index (BMI) and Fat Mass (FM; electrical bioimpedance). The references used to establish prevalence according to BMI were those of the World Health Organization (WHO) and the International Obesity Task Force (IOTF); in the case of FM, the Child Growth Foundation (CGF) reference was used. There were significant differences (p < 0.05) in the prevalence of overweight and obesity between the three classifications (32.3% according to IOTF, 37.3% according to WHO, and 39.8% according to CGF), being higher in males. WHO-IOTF concordance was substantial (kappa = 0.793), whereas concordances WHO-CGF (kappa = 0.504) and IOTF-CGF (kappa = 0.447) were moderate. The authors recommend evaluating overweight and obesity not only with BMI, but also with FM, and always specify the references used.

Physical performance metrics in elite soccer: do power and acceleration metrics provide insight into positional demands and match-related fatigue in the 4-3-3 system?

Abstract: BACKGROUND The aim of this study was to quantify power and acceleration metrics in elite soccer matches to gain an insight into positional demands and match-related fatigue patterns. METHODS Elite players (N.=212, observations =522) were analysed during 50 matches of the Italian Serie A using a semi-automatic tracking system (K-Sport, Montelabbate, Pesaro-Urbino, Italy - Stats, Leeds, UK) during the 2015/16 season. A principal component analysis (PCA) was performed to find the latent variables that better explain the huge amount of data collected; an ANOVA was performed to find differences among positional roles and a mixed factorial analysis of mixed data (FAMD) was carried out to investigate the patterns of fatigue over time. RESULTS Power and acceleration were defined as the latent variables out of the 19 investigated that provided most of the variance (90.39%); significant differences among roles were found (P 0.14) and significant patterns of fatigue (P<0.05) with a moderate to large ES were observed over time in some of the key performance indicators. CONCLUSIONS The data demonstrate that there are implications for developing power and acceleration in training sessions and assessing these components during a game. With the introduction of "live streaming" of GPS data, the movement patterns could be observed in real time, and interchanges could be made before the onset of fatigue and before evident reductions in performance might be observed.

Visual dependency and postural control on swing performance in golf players

Abstract: Individuals have to reweight the respective contribution of the different sources of sensorial information for regulating posture and balance, especially during fine task execution. Given the evide...