Assessing experience in the deliberate practice of running using a fuzzy decision-support system.

The judgement of skill experience and its levels is ambiguous though it is crucial for decision-making in sport sciences studies. We developed a fuzzy decision support system to classify experience of non-elite distance runners. Two Mamdani subsystems were developed based on expert running coaches' knowledge. In the first subsystem, the linguistic variables of training frequency and volume were combined and the output defined the quality of running practice. The second subsystem yielded the level of running experience from the combination of the first subsystem output with the number of competitions and practice time. The model results were highly consistent with the judgment of three expert running coaches (r>0.88, p<0.001) and also with five other expert running coaches (r>0.86, p<0.001). From the expert's knowledge and the fuzzy model, running experience is beyond the so-called "10-year rule" and depends not only on practice time, but on the quality of practice (training volume and frequency) and participation in competitions. The fuzzy rule-based model was very reliable, valid, deals with the marked ambiguities inherent in the judgment of experience and has potential applications in research, sports training, and clinical settings.

What is the best method for child longitudinal plantar arch assessment and when does arch maturation occur?

BACKGROUND: The medial longitudinal arch modifies significantly during growth. Nevertheless, authors differ on the age at which the foot acquires the adult-like shape. The best method to assess this arch in children is also controversial. OBJECTIVES: Characterize the longitudinal arch of children between 3 and 10 years and compare the applicability of five evaluation methods. METHODS: Plantar prints were acquired from 391 healthy preschools children from the University of Sao Paulo, Brazil. We calculated the arch indexes of: Cavanagh and Rodgers, Chipaux-Smirak, Staheli and the Alfa Angle, and compared them with the feet posture assessment. Non-parametric tests were used to compare among methods and ages. Spearman correlation was used to establish relationships among indexes. RESULTS: 3 and 4 years old showed a high prevalence of low arches (36-86%). Between 4 and 5 years old, significant difference was observed for all indexes. The indexes presented good correlation among them, although the proportions of the different arch types were different for each age group (p<0.001). CONCLUSIONS: The longitudinal arch acquires an adult-like shape progressively, being statistically notorious the moment of medial longitudinal arch's formation between 4 and 5 years old. The Chipaux-Smirak Index is the best index to assess children's feet; it provides a better classification for lower arches and is easily calculated.