Physical capacity and match running performance in very young soccer players

Aim. The aim of this study was to analyze match running performance in relation to age and individual physical capacity in youth soccer players aged 8-10 years. Methods. Physical capacity of 12 under-10 (U10) and 15 under-8 (U8) male players was assessed by counter movement jump (CMJ), 20 meter shuttle run (20m-SR) and 10, 20 and 30 meters (10m, 20m and 30m) sprint tests. Shuttle dribble test (SHD) and slalom dribble test (SLD) were also performed to evaluate technical ability. Time motion analyses by global positioning system (K-Gps 10Hz, K-Sport) were performed during 30 (200 observations) official matches (lasting three equal periods of 15-min). Results. U10 vs U8 showed a better shuttle-running performance (1215\ub177 vs 872\ub178m, p<0.005), a lower sprint time on 20m (4.15\ub10.05 vs 4.38\ub10.07s, p<0.05) and 30m (5.72\ub10.06 vs 6.31\ub10.08s, p<0.0001) and a better technical ability (SDL: 10.7\ub10.2 vs 11.8\ub10.2, p<0.001; SHD: 22.3\ub10.3 vs 29.4\ub10.7s, p<0.0001). No differences were observed in CMJ and 10m. U10 covered higher total (3437\ub1137 vs 2348\ub1124m, p<0.0001) and high-intensity distance (1455\ub1104m vs 992\ub1116m, p<0.005) than U8. Distance covered at high-intensity in the third time was not significantly different from first and second time both for U10 and U8. A linear relationship (r2=0.74, p<0.0001) was observed between high-intensity distance and 20m-SR. Conclusions. This is the first study characterizing the match running activity of very young soccer players. If confirmed in a larger population, these data could be used by coaches and support staff as starting point in the design of training programs

An agenda for creative practice in the new mobilities paradigm

Creative practices have made a standing contribution to mobilities research. We write this article as a collective of 25 scholars and practitioners to make a provocation: to further position creative mobilities research as a fundamental contribution and component in this field. The article explores how creative forms of research—whether in the form of artworks, exhibitions, performances, collaborations, and more—has been a foundational part of shaping the new mobilities paradigm, and continues to influence its methodological, epistemological, and ontological concerns. We tour through the interwoven history of art and mobilities research, outlining five central contributions that creativity brings. Through short vignettes of each author’s creative practice, we discuss how creativity has been key to the evolution and emergence of how mobilities research has expanded to global audiences of scholars, practitioners, and communities. The article concludes by highlighting the potency of the arts for lively and transdisciplinary pathways for future mobilities research in the uncertainties that lay ahead

Match running performance and physical capacity profiles of U8 and U10 soccer players

Aim This study aimed to characterize match running performance of very young soccer players and evaluate the relationship between these data and physical capacities and technical skills. Methods Distances covered at different speed thresholds were measured during 31 official matches using GPS technology in U10 (n = 12; age 10.1 ± 0.1 years) and U8 (n = 15; age 7.9 ± 0.1 years) national soccer players. Counter movement jump performance (CMJ), 20 m shuttle running (20 m-SR), linear sprint performance (10, 20, 30 m), shuttle (SHDT) and slalom dribble tests (SLDT) were performed to determine the players physical capacities and technical skills. Results Physical capacities and technical skills were higher in U10 versus U8 players [P 0.05, ES: 0.74). The U10 players covered more total (TD) and high-intensity running distance (HIRD) than their younger counterparts did (P 0.05, ES: 0.99). TD and HIRD covered across the three 15 min periods of match play did not decline (P > 0.05, ES: 0.02–0.55). Very large magnitude correlations were observed between the U8 and U10 players performances during the 20 m-SR versus TD (r = 0.79; P < 0.01) and HIRD (r = 0.82; P < 0.01) covered during match play. Conclusions Data demonstrate differences in match running performance and physical capacity between U8 and U10 players, and large magnitude relationships between match play measures and physical test performances. These findings could be useful to sports science staff working within the academies

Prion Protein Accumulation In Lipid Rafts of Mouse Aging Brain

The cellular form of the prion protein (PrP(C)) is a normal constituent of neuronal cell membranes. The protein misfolding causes rare neurodegenerative disorders known as transmissible spongiform encephalopathies or prion diseases. These maladies can be sporadic, genetic or infectious. Sporadic prion diseases are the most common form mainly affecting aging people. In this work, we investigate the biochemical environment in which sporadic prion diseases may develop, focusing our attention on the cell membrane of neurons in the aging brain. It is well established that with aging the ratio between the most abundant lipid components of rafts undergoes a major change: while cholesterol decreases, sphingomyelin content rises. Our results indicate that the aging process modifies the compartmentalization of PrP(C). In old mice, this change favors PrP(C) accumulation in detergent-resistant membranes, particularly in hippocampi. To confirm the relationship between lipid content changes and PrP(C) translocation into detergent-resistant membranes (DRMs), we looked at PrP(C) compartmentalization in hippocampi from acid sphingomyelinase (ASM) knockout (KO) mice and synaptosomes enriched in sphingomyelin. In the presence of high sphingomyelin content, we observed a significant increase of PrP(C) in DRMS. This process is not due to higher levels of total protein and it could, in turn, favor the onset of sporadic prion diseases during aging as it increases the PrP intermolecular contacts into lipid rafts. We observed that lowering sphingomyelin in scrapie-infected cells by using fumonisin B1 led to a 50% decrease in protease-resistant PrP formation. This may suggest an involvement of PrP lipid environment in prion formation and consequently it may play a role in the onset or development of sporadic forms of prion diseases

Match running performance and physical capacity profiles of U8 and U10 soccer players

Aim: This study aimed to characterize match running performance of very young soccer players and evaluate the relationship between these data and physical capacities and technical skills. Methods: Distances covered at different speed thresholds were measured during 31 official matches using GPS technology in U10 (n = 12; age 10.1 ± 0.1 years) and U8 (n = 15; age 7.9 ± 0.1 years) national soccer players. Counter movement jump performance (CMJ), 20 m shuttle running (20 m-SR), linear sprint performance (10, 20, 30 m), shuttle (SHDT) and slalom dribble tests (SLDT) were performed to determine the players physical capacities and technical skills. Results: Physical capacities and technical skills were higher in U10 versus U8 players [P  0.05, ES: 0.74). The U10 players covered more total (TD) and high-intensity running distance (HIRD) than their younger counterparts did (P  0.05, ES: 0.99). TD and HIRD covered across the three 15 min periods of match play did not decline (P > 0.05, ES: 0.02–0.55). Very large magnitude correlations were observed between the U8 and U10 players performances during the 20 m-SR versus TD (r = 0.79; P < 0.01) and HIRD (r = 0.82; P < 0.01) covered during match play. Conclusions: Data demonstrate differences in match running performance and physical capacity between U8 and U10 players, and large magnitude relationships between match play measures and physical test performances. These findings could be useful to sports science staff working within the academies

Match running activity in very young soccer players

Aim. The aim of this study was to quantify match play intensity distribution in 8-10 years soccer players and to analyze the results in relation to age and physical capacity. Methods. Physical capacity of 12 under-10 (U10) and 15 under-8 (U8) male players was assessed by counter movement jump (CMJ), 20 meter shuttle run (20m-SR) and 10, 20 and 30 meters (10m, 20m and 30m) sprint tests. Shuttle dribble test (SHD) and slalom dribble test (SLD) were also performed to evaluate technical ability. Time motion analyses by global positioning system (GPS 10Hz, K-Sport) were performed during 30 (200 observations) national matches (3 times, 15 minutes each). Distance covered was categorized into 6 intensity zone (standing, walking, jogging, running, high-speed running, sprinting) according to transition from walking to running (1), ratio of the commonly used thresholds for senior (2) and \u2018\u2018flying\u2019\u2019 10m sprint time (3). Results. U10 vs U8 showed a better shuttle-running performance (1215\ub177 vs 872\ub178 m), a lower sprint time on 20m (4.15\ub10.05 vs 4.38\ub10.07 sec) and 30m (5.72\ub10.06 vs 6.31\ub10.08 sec) and a better technical ability (10.7\ub10.2 vs 11.8\ub10.2 and 22.3\ub10.3 vs 29.4\ub10.7 sec, in SLD and SHD, respectively). No differences were observed in CMJ (24.4\ub10.8 vs 23.3\ub10.9 cm) and 10m (2.45\ub10.02 vs 2.52\ub10.04 sec). Match running activity showed an higher total and high-intensity distance covered by U10 (3386\ub1120 and 1369\ub195 m, respectively) vs U8 (2354\ub159 and 887\ub158 m, respectively). Considering only the players (n=16) that performed the entire match, distance covered at high-intensity in the third time was not significantly different from first and second time both for U10 and U8. Finally, a linear relationship (r2=0.62, p<0.01) was observed between high-intensity distance covered and 20m-SR performance in U10 and U8. Conclusions. This is the first study characterizing the running match activity of very young soccer players. If confirmed in a larger population, these data could be used by coaches and support staff as starting point in the design of effective training programs. References. 1) Saibene & Minetti. Biomechanical and physiological aspects of legged locomotion in humans. Eur J Appl Physiol, 2003, 88, 297-316. 2) Bradley et al. High-intensity running in English FA Premier League soccer matches. Journal Sports Sciences, 2009, 27, 159\u2013168. 3) Harley et al. Motion analysis of match-play in elite U12 to U16 age-group soccer players. J Sports Sci, 2010, 28, 1391-1397

Evaluation of skeletal muscle oxidative metabolism in Alzheimer disease

Aim: Recently evidence has been provided that Beta-amyloid (bAP) deposits, the pathogenetic feature of Alzheimer disease (AD) [1, 2], can be also present in the mitochondria of skeletal muscle cells [3]. The aim of this study was to evaluate whether in AD patients bAP deposits in skeletal muscle impair oxidative metabolism. Methods: Thirteen AD patients (73.5 \ub1 1.0 years, mean \ub1 SD) and twenty-nine healthy sex-matched control subjects (CTRL) (73.3 \ub1 1.1 years) were investigated. Two incremental exercise until voluntary exhaustion were performed, in order to evaluate skeletal muscle oxidative metabolism: a cycloergometer (CE) and a one-leg knee extension (KE) exercise. The following variables were determined: breath-by-breath pulmonary O2 uptake (VO2); heart rate (HR); cardiac output (CO); vastus lateralis muscle fractional O2 extraction by near-infrared spectroscopy (D[deoxy(Hb \ub1 Mb)]); blood lactate concentration ([La-]) at rest and after exercise; maximal voluntary contraction (MVC); total daily energy expenditure (TEE). Results: During CE, peak work-rate (94.1 \ub1 7.1 vs. 128.3 \ub1 8.5 watt) and VO2 peak (22.0 \ub1 0.8 vs. 26.4 \ub1 1.1 mL kg-1 min-1) were significantly lower in AD patients vs. CTRL. CO was similar between AD patients (14.4 \ub1 0.5 L min-1) and CTRL (15.3 \ub1 0.9 L min-1) whereas D[deoxy(Hb \ub1 Mb)] was significantly lower in AD patients (51.05 \ub1 5.8 %) vs. CTRL (71.4 \ub1 2.9 %). During KE, VO2 peak (10.7 \ub1 0.7) vs. 13.5 \ub1 0.6 mL kg-1 min-1) and D[deoxy(Hb \ub1 Mb)] (40.02 \ub1 5.8 vs. 61.01 \ub1 4.7 %) were significantly lower in AD patients vs. CTRL. CO (10.93 \ub1 0.5 vs. 11.62 \ub1 0.9) and [La-] were not significantly different between AD and CTRL. TEE was similar in AD and CTRL (2,534 \ub1 243.6 vs. 2,250 \ub1 119.3 kcal day-1). As for MVC, no significant difference was found between CTRL and AD (440.5 \ub1 39.5 N vs. 438.3 \ub1 86.7 N, respectively). Conclusion: Data from the present study indicate that AD patients have a reduced exercise capacity compared to healthy control subjects, probably due to a reduced muscle fractional O2 extraction capacity. Indeed, the impairment of muscle oxidative function was evident also during KE, when cardiovascular constraints to oxidative metabolism were reduced. References Harrison J (2013) Med Clin North Am 97:425\u2013438 Kuo et al (2000) Am J Pathol 156:797\u2013805 Parker Jr et al (1994) Neurology 44:1086\u20131090 Shea et al (2012) Curr Top Med Chem 12:2596\u2013261