The present study aimed to determine the contribution of soccer players' anthropometric features to predict their physical performance. Sixteen players, from a professional youth soccer academy, were recruited. Several anthropometric features such as corrected arm muscle area (AMA corr ), arm muscle circumference (AMC) and right and left suprapatellar girths (RSPG and LSPG) were employed in this study. Players' physical performance was assessed by the change of direction (COD), sprint (10-m and 20-m), and vertical jump (CMJ) tests, and Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IRT1). Using an extra tree regression (ETR) model, the anthropometric features permitted to accurately predict 10-m sprint, 20-m sprint and Yo-Yo IRTL 1 performance (p < 0.05). ETR showed that upper-body features as AMA corr , and AMC affected 10-m and 20-m sprint performances, while lower-body features as RSPG and LSPG influenced the Yo-Yo IRTL 1 (Overall Gini importance ≥ 0.22). The model predicting COD and CMJ presented a poor level of prediction, suggesting that other factors, rather than anthropometric features, may concur to predict their changes in performance. These findings demonstrated that the upper-and lower-body anthropometric features are strictly related to sprint and aerobic fitness performance in elite youth soccer.

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Lesions of the quadriceps muscle (QM) are frequently seen by sonographers, and in most cases they are the result of sports-related trauma. An accurate assessment of the severity of the lesion is essential, particularly when the patient is a professional athlete. In most cases, careful history-taking and a thorough physical examination are sufficient for making the diagnosis and indicating the most suitable imaging studies for each case. Clinical assessment alone, however, may not be sufficient for distinguishing contusions from small, partial tears or for estimating the size of a tear. Therefore, at least in patients who are professional athletes, imaging studies are necessary to plan appropriate therapy that will allow prompt functional recovery.Muscles cannot be visualized with conventional radiography, but it is used routinely in prepubertal patients because it can detect apophyseal detachments, which are the most frequent muscle lesion in this age group. Radiography is also useful when myositis ossificans is suspected. Magnetic resonance imaging, thanks to its excellent tissue contrast, allows simultaneous assessment of muscle, joint, and bone planes. It remains a second-line study due to its high cost and relatively low availability. It is also associated with various contraindications, the most important of which is the presence of a cardiac pacemaker. Ultrasonography has a number of advantages, including widespread availability, absence of contraindications, and low cost. It can also be used for dynamic studies of the muscle during contraction and relaxation, and if doubts arise, scans can easily be obtained of the contralateral muscle for comparison purposes. These qualities make it an excellent tool for follow-up of patients with QM lesions, when follow-up is necessary. This article reviews the anatomy of the QM, the technique used for standard ultrasound examination of this muscle, its normal appearance on ultrasound, and the sonographic characteristics of the most common traumatic lesions that affect it.Sommario Le lesioni del muscolo quadricipite (MQ) sono frequenti nella pratica ecografica quotidiana e, nella gran maggioranza dei casi, sono secondarie a traumi, per lo più sportivi. Un'accurata valutazione della gravità delle lesioni è necessaria, in particolare quando siano coinvolti sportivi di alto livello. * Corresponding author. CIM SA, Route de Malagnou 40a,

Purpose: This observational longitudinal investigation aimed to investigate whether change in bioelectrical regional phase angle (PhA) is a predictor of change in vertical jump performance in elite soccer players. Methods: Fifteen soccer players (age: 28.7 ± 5.0 years, body weight: 82.4 ± 6.8 kg, height: 186.0 ± 0.1 cm, body mass index: 23.8 ± 1.2 kg/m2) competing in the first Italian division (Serie A) were included in this study and tested before the pre-season period and after the first half of the championship. Whole body and lower hemisoma PhA were obtained with a phase-sensitive 50 kHz bioelectrical impedance analyzer and legs lean soft tissue was estimated using specific bioimpedance-based equation developed for athletes. Vertical jump performance was assessed using the countermovement jump (CMJ). Results: The major findings of the study are that changes in lower hemisoma PhA are more strongly related with changes in jump performance (r2 = 0.617, p = 0.001) than changes in whole-body PhA (r2 = 0.270, p = 0.047), even after adjusting for legs lean soft tissue and for body mass index (β = 5.17, p = 0.004). Conclusions: These data suggest that changes in lower hemisoma PhA might be used as a tool for evaluating performance related parameters in sports where specific body segments are involved, in preference to the whole-body measured value.

Purpose: Bioimpedance data through bioimpedance vector analysis (BIVA) is used to evaluate cellular function and body fluid content. This study aimed to (i) identify whether BIVA patters differ according to the competitive period and (ii) provide specific references for assessing bioelectric properties at the start of the season in male elite soccer players. Methods: The study included 131 male soccer players (age: 25.1 ± 4.7 yr, height: 183.4 ± 6.1 cm, weight: 79.3 ± 6.6) registered in the first Italian soccer division (Serie A). Bioimpedance analysis was performed just before the start of the competitive season and BIVA was applied. In order to verify the need for period-specific references, bioelectrical values measured at the start of the season were compared to the reference values for the male elite soccer player population. Results: The results of the two-sample Hotelling T2 tests showed that in the bivariate interpretation of the raw bioimpedance parameters (resistance (R) and reactance (Xc)) the bioelectric properties significantly (T2 = 15.3, F = 7.6, p ≤ 0.001, Mahalanobis D = 0.45) differ between the two phases of the competition analyzed. In particular, the mean impedance vector is more displaced to the left into the R-Xc graph at the beginning of the season than in the first half of the championship. Conclusions: For an accurate evaluation of body composition and cellular health, the tolerance ellipses displayed by BIVA approach into the R-Xc graph must be period-specific. This study provides new specific tolerance ellipses (R/H: 246 ± 32.1, Xc/H: 34.3 ± 5.1, r: 0.7) for performing BIVA at the beginning of the competitive season in male elite soccer players.