Body size, skeletal maturity and functional characteristics of elite academy soccer players on entry between 1992 and 2003

Secular changes in body size, estimated fatness, skeletal maturation, and functional characteristics of youth soccer players on entry into an elite academy between 1992 and 2003 were compared. Annual selections grouped across time (1992–1995, 1996–1998, 1999–2003), playing position (goalkeeper, defender, midfielder, forward), and by eventual status in the sport (professional, non-professional) were compared. Data for 158 players (age 13.4 ± 0.4 years) at entry into the academy included skeletal age (Greulich-Pyle method), height, weight, relative fatness, four field tests of functional capacities (aerobic, anaerobic, power, speed), and quadriceps concentric strength of the dominant and non-dominant legs. MANCOVA with age as the covariate and chi square were used for comparisons across years. With few exceptions (but notably estimated [Vdot]O2max), results for player size, functional characteristics, and skeletal maturation did not differ among years. Distributions of players by skeletal maturity status and within each playing position also did not differ between years. Although related research has suggested that the anthropometric characteristics of professional players and demands of contemporary professional soccer competition increased over this period, the size, maturity, and functional characteristics of youth players on entry to an elite academy and of graduates who eventually played soccer as professionals generally did not change across annual selections from 1992 to 2003. The results suggest a lack of change in selection philosophies and practices of coaches involved in recruiting players for the academy, which in turn is reflected in consistency of specific evaluation criteria employed over the decade considered

Anthropometric and motor characteristics of senegalese children with different nutritional histories

The effects of protein energy malnutrition (PEM) on the motor performance of 4.5-6.5-year-old Senegalese children were studied. Body dimensions included weight, lengths, circumferences, and four skinfolds. Motor performance tests included a 3-min endurance run, 4 X 10 m shuttle-run, distance throw, standing long jump and grip strength. The sample consisted of 147 children : 52 children who were hospitalized for severe undernutrition (severe UN group) during infancy but who had been nutritionally rehabilited ; 63 children who were never severely malnourished but who were chronically exposed to mild-to-moderate undernutrition up to the time of study (chronic UN group) ; and 32 well nourished children (well nourished group) from well-off households. After adjusting for sex and age, the well nourished group performed better than the severe UN and chronic UN groups. Principal components analysis resulted in two factors which explained 65% of the variance in anthropometry and motor performance. One was related to body size and the second to body composition. The three nutritional groups differed significantly in principal component scores for the two factors ; chronic UN and severe UN children also differed for the second factor. Body composition, especially low fat mass appeared to be an important feature for motor performance in chronically undernourished children. (Résumé d'auteur

Bio-banding in Sport: Applications to Competition, Talent Identification, and Strength and Conditioning of Youth Athletes

Bio-banding is the process of grouping athletes on the basis of attributes associated with growth and maturation, rather than chronological age. Children of the same age may vary considerably in biological maturation with some individuals maturing well in advance or delay of their peers. The timing of maturation has important implications for competition, talent identification and training. Increased awareness and interest in the subject of maturation has sparked a renewed interest in the study and application of bio-banding. This overview describes the purpose and process of bio-banding, potential benefits and limitations, and also presents some recent advances in its application in youth sports

Designing touch-enabled electronic flight bags in SAR helicopter operations

In order to benefit from potential reduced operational costs and crew workload airlines are increasingly interested in touchscreen-based Electronic Flight Bags (EFB). This paper focuses on the specific domain of Search and Rescue (SAR) Helicopters. A first set of results aiming to explore and understand potential benefits and challenges of an EFB in a SAR environment will be presented. A review of related work, operational observations and interviews with pilots were conducted to understand and specify the use context. Digital Human Modelling (DHM) software was used to determine physical constraints of an EFB in this type of flight deck. A scenario was developed which will be used in future to define features, content and functionality that a SAR pilot may wish to see in an EFB. Developed initial interface design guidelines are presented

Impact of youth sports specialisation on career and task-specific athletic performance: A systematic review following the American Medical Society for Sports Medicine (AMSSM) Collaborative Research Network's 2019 Youth Early Sport Specialisation Summit

Objective The impact, positive or negative, of youth sport specialisation (YSS) on short-Term and long-Term performance is not fully understood; however, the desire to maximise performance goals is generally considered the primary reason children and adolescents specialise at a young age. We performed a systematic review of original research to establish the association of YSS and task-focused or career-focused performance outcomes. Design Systematic review. Data sources Databases searched include PubMed, EMBASE, Cochrane, CINAHL and SPORTDiscus. Eligibility criteria We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify peer-reviewed research articles published in English between 1 January 1990 and 31 December 2018 that reported original findings on the association of YSS and performance outcomes. Studies without an explicit measure of sport specialisation, for example, volume measures without measuring sport specialisation, were excluded. Results Twenty-Two articles were included in the final review; 15 addressed career performance outcomes and 7 considered task performance outcomes. All identified studies were cross-sectional or retrospective in design. The proportion of elite athletes who specialised early ranged between 7% and 85%, depending on sport and definition of specialisation. Elite athletes often specialised between the ages of 14 and 15 compared with their non-elite or semi-elite peers who typically specialised prior to 13 years. In addition, neuromuscular control, anterior reach asymmetry and physical task outcomes did not differ by specialisation status. Conclusion The volume and methodological rigour of published research in this field are limited. Our review suggests that YSS is not required to achieve success at elite levels. YSS also does not appear to improve task-related performance (eg, anterior reach, neuromuscular control) outcomes for specialised athletes when compared with non-specialised athletes during childhood and adolescence