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Our Methodology

Our approach draws from peer-reviewed research in youth athletic development. While we use validated methods, this tool is designed for exploration and guidance, not clinical diagnosis or talent guarantees.

This assessment provides directional guidance based on established sports science research. Results reflect current observations and are not predictive of future athletic outcomes. Individual development varies significantly. Consult qualified coaches and medical professionals for personalized guidance.

References

  • Mirwald, R.L., Baxter-Jones, A.D.G., Bailey, D.A., & Beunen, G.P. (2002). An assessment of maturity from anthropometric measurements. Medicine & Science in Sports & Exercise, 34(4), 689-694.
  • Khamis, H.J., & Roche, A.F. (1994). Predicting adult stature without using skeletal age: The Khamis-Roche method. Pediatrics, 94(4), 504-507.
  • Cumming, S.P., Lloyd, R.S., Oliver, J.L., Eisenmann, J.C., & Malina, R.M. (2017). Bio-banding in Sport: Applications to Competition, Talent Identification, and Strength and Conditioning of Youth Athletes. Strength & Conditioning Journal, 39(2), 34-47. (Judging a child against biological maturity rather than chronological age — the basis for reading maturity-sensitive test scores through a growth-timing lens, pioneered with the English Premier League.)
  • Council of Europe. (1988). Eurofit: Handbook for the Eurofit Tests of Physical Fitness. Rome: Council of Europe, Committee for the Development of Sport.
  • Canadian Sport for Life. Long-Term Athlete Development Framework. Sport for Life Society.
  • Eckner, J.T., Kutcher, J.S., & Richardson, J.K. (2010). Pilot evaluation of a novel clinical test of reaction time in National Collegiate Athletic Association Division I football players. Journal of Athletic Training, 45(4), 327-332. (Validated the drop-stick / falling-ruler method of measuring simple reaction time — catch distance converts to time via free-fall physics, t = √(2d/g). The home ruler-drop self-check rests on the same principle.)
  • Kuczmarski, R.J., et al. (2000). CDC Growth Charts: United States. Advance Data, 314, 1-27. National Center for Health Statistics.
  • Norton, K., & Olds, T. (1996). Anthropometrica: A textbook of body measurement for sports and health courses. UNSW Press.
  • Carter, J.E.L., & Heath, B.H. (1990). Somatotyping: Development and Applications. Cambridge University Press. (Source of the Heath-Carter anthropometric somatotype — endomorphy, mesomorphy, ectomorphy — and the somatochart. Mesomorphy here uses elbow/knee bone breadths and limb girths; endomorphy is estimated from BMI percentile since a home protocol takes no skinfolds.)
  • Manning, J.T. (2002). Digit Ratio: A Pointer to Fertility, Behavior, and Health. Rutgers University Press. (The 2D:4D index-to-ring finger ratio as a proposed marker of prenatal androgen exposure, with associations to sporting and spatial ability. Treated here as an exploratory constitutional marker, not a deterministic predictor.)
  • Scholz, M.N., Bobbert, M.F., van Soest, A.J., Clark, J.R., & van Heerden, J. (2008). Running economy and the indirect estimation of the Achilles tendon moment arm. Journal of Experimental Biology, 211(20), 3266-3271. (Shorter Achilles tendon moment arms are associated with better running economy — the basis for the short-heel-lever 'spring' reading.)
  • Lee, S.S.M., & Piazza, S.J. (2009). Built for speed: musculoskeletal structure and sprinting ability. Journal of Experimental Biology, 212(22), 3700-3707. (Sprinters tend to have shorter plantarflexor moment arms and longer toes, lengthening force-application time — the foot-lever basis for the heel-lever reading.)
  • Gabbett, T., & Georgieff, B. (2007). Physiological and anthropometric characteristics of Australian junior national, state, and novice volleyball players. Journal of Strength and Conditioning Research, 21(3), 902-908. (Standing reach and spike/block reach discriminate junior players by selection level — the basis for reading vertical reach as an overhead-sport lever. Standing reach is also the headline NBA/volleyball combine measurement and featured in Eastern-bloc reach screening for net and overhead sports.)
  • Tanner, J.M., Goldstein, H., & Whitehouse, R.H. (1970). Standards for children's height at ages 2-9 years allowing for height of parents. Archives of Disease in Childhood, 45(244), 755-762. (Origin of the mid-parent method — averaging the two parents to set a child's expected stature. Applied here to body proportion rather than height: average the parents' build into a family pattern, then read the child against it.)
  • Livshits, G., Roset, A., Yakovenko, K., Trofimov, S., & Kobyliansky, E. (2002). Genetics of human body size and shape: body proportions and indices. Annals of Human Biology, 29(3), 271-289. (Limb and torso proportion indices show substantial familial/genetic resemblance — the basis for reading a child's measured proportions as tracking or diverging from the mid-parent family pattern, while treating heredity as a tendency rather than a copy.)
  • Allen, M.S., Greenlees, I., & Jones, M. (2013). Personality in sport: A comprehensive review. International Review of Sport and Exercise Psychology, 6(1), 184-208. (Review of trait/temperament dimensions — composure, drive, conscientiousness — in athletic populations.)
  • Duckworth, A.L., Peterson, C., Matthews, M.D., & Kelly, D.R. (2007). Grit: Perseverance and passion for long-term goals. Journal of Personality and Social Psychology, 92(6), 1087-1101. (Grit — sustained effort and interest toward long-term goals — as a predictor of achievement; the basis for the grit dimension.)
  • Porac, C., & Coren, S. (1976). The dominant eye. Psychological Bulletin, 83(5), 880-897. (Eye dominance and laterality; cross-dominance — eye opposite to hand — is of long-standing interest in aiming and interceptive sports.)
  • Musch, J., & Grondin, S. (2001). Unequal competition as an impediment to personal development: A review of the relative age effect in sport. Developmental Review, 21(2), 147-167. (Children born early in a sport's selection year are relatively older and over-represented in talent pools; the basis for the relative-age insight.)
  • Barnsley, R.H., Thompson, A.H., & Barnsley, P.E. (1985). Hockey success and birthdate: The relative age effect. CAHPER Journal, 51(1), 23-28. (The original demonstration of the relative age effect in youth sport.)
  • Bayley, N., & Pinneau, S.R. (1952). Tables for predicting adult height from skeletal age: revised for use with the Greulich-Pyle hand standards. The Journal of Pediatrics, 40(4), 423-441. (Source of the 'percent of mature height attained by age' table used in predictAdultHeight; the ages 6-18 values were cross-checked against CDC 2000 stature-for-age medians.)
  • de Onis, M., Onyango, A.W., Borghi, E., Siyam, A., Nishida, C., & Siekmann, J. (2007). Development of a WHO growth reference for school-aged children and adolescents. Bulletin of the World Health Organization, 85(9), 660-667. (5-19y BMI-for-age reference; used to cross-check the CDC 2000 median BMI-for-age values that back getBMIPercentile.)
  • Lloyd, R.S., & Oliver, J.L. (2012). The Youth Physical Development Model: A New Approach to Long-Term Athletic Development. Strength & Conditioning Journal, 34(3), 61-72.
  • Plowman, S.A., & Meredith, M.D. (Eds.). (2013). Fitnessgram/Activitygram Reference Guide (4th ed.). Dallas, TX: The Cooper Institute.
  • Vaeyens, R., Lenoir, M., Williams, A.M., & Philippaerts, R.M. (2008). Talent Identification and Development Programmes in Sport: Current Models and Future Directions. Sports Medicine, 38(9), 703-714. (Reviews national talent-ID systems including the AIS Talent Search and the former GDR, whose motor/anthropometric test batteries — sprint, jump, throw, shuttle — parallel ours.)
  • Cote, J., Lidor, R., & Hackfort, D. (2009). ISSP Position Stand: To Sample or to Specialize? Seven Postulates About Youth Sport Activities that Lead to Continued Participation and Elite Performance. International Journal of Sport and Exercise Psychology, 7(1), 7-17.
  • Guellich, A., & Emrich, E. (2014). Considering long-term sustainability in the development of world class success. European Journal of Sport Science, 14(sup1), S383-S397.
  • Tomkinson, G.R., Lang, J.J., Tremblay, M.S., Dale, M., LeBlanc, A.G., Belanger, K., Ortega, F.B., & Léger, L. (2017). International normative 20 m shuttle run values from 1,142,026 children and youth representing 50 countries. British Journal of Sports Medicine, 51(21), 1545-1554.
  • Ortega, F.B., Leskošek, B., Blagus, R., Gil-Cosano, J.J., Mäestu, J., Tomkinson, G.R., et al. (2023). European fitness landscape for children and adolescents: updated reference values, fitness maps and country rankings based on nearly 8 million test results from 34 countries gathered by the FitBack network. British Journal of Sports Medicine, 57(5), 299-310. (Source of the standing-broad-jump teen norms; first-authored by Ortega, not Tomkinson.)
  • Berisha, M., & Cilli, M. (2017). Comparison of Eurofit Test Results of 11-17-Year-Old Male and Female Students in Kosovo. European Scientific Journal, 13(31), 138-154. (Bent-arm hang reference data informing the teen dead-hang bands.)
  • Raya-González, J., Bishop, C., Gómez-Piqueras, P., Veiga, S., Viejo-Romero, D., & Navandar, A. (2020). Strength, Jumping, and Change of Direction Speed Asymmetries Are Not Associated With Athletic Performance in Elite Academy Soccer Players. Frontiers in Psychology, 11, 175. (Change-of-direction data used directionally to shape the teen agility bands; not published Illinois-test norms.)
  • Biggar, C., Larson, A., & DeBeliso, M. (2022). Establishing Normative Reference Values for the Utah Seated Medicine Ball Throw Protocol in Adolescents. The Sport Journal (United States Sports Academy). (Earlier bioRxiv preprint, 2021: doi:10.1101/2021.12.14.472637.)
  • Greier, K., Drenowatz, C., Ruedl, G., Kirschner, W., Mitmannsgruber, P., & Greier, C. (2019). Physical Fitness across 11- to 17-Year-Old Adolescents: A Cross-Sectional Study in 2267 Austrian Middle- and High-School Students. Advances in Physical Education, 9(4), 258-269. (German Motor Test, DMT 6-18; informs teen sprint norms.)
  • Mascherini, G., Buglione, N., Ciani, V., Tirinnanzi, F., Bini, V., & Levi Micheli, M. (2022). Florentine Normative Values for Physical Fitness in Adolescents Aged 14-15 Years. Healthcare, 10(12), 2486.
  • Myers, B.A., Jenkins, W.L., Killian, C., & Rundquist, P. (2014). Normative data for hop tests in high school and collegiate basketball and soccer players. International Journal of Sports Physical Therapy, 9(5), 596-603. (Cohort ages 14-24; triple-hop reference informing the teen hop bands.)
  • Nowak, M., Szymanek-Pilarczyk, M., Stolarczyk, A., Oleksy, Ł., Muracki, J., & Wąsik, J. (2025). Normative and limit values of speed, endurance and power tests results of young football players. Frontiers in Physiology, 15, 1502694. (Youth sprint centiles; previously cited in-code only as PMC11751035.)
  • Mainer-Pardos, E., Gonzalo-Skok, O., Nobari, H., Lozano, D., & Pérez-Gómez, J. (2021). Age-related differences in linear sprint in adolescent female soccer players. BMC Sports Science, Medicine and Rehabilitation, 13(1), 97. (Adolescent female sprint splits; previously cited in-code only as PMC8381494.)
  • Beighton, P., Solomon, L., & Soskolne, C.L. (1973). Articular mobility in an African population. Annals of the Rheumatic Diseases, 32(5), 413-418. (The 9-point Beighton score for generalised joint hypermobility, modifying Carter & Wilkinson's 1964 system — the de-facto standard for 50+ years, long used to flag fit for gymnastics, dance and diving and to screen joint-stability/injury risk.)
  • Bosco, C., & Komi, P.V. (1979). Mechanical characteristics and fiber composition of human leg extensor muscles. European Journal of Applied Physiology and Occupational Physiology, 41(4), 275-284. (Vertical-jump performance tracks the percentage of fast-twitch fibers in the leg extensors — the basis for reading explosive test results as a fast-twitch indicator.)
  • Costill, D.L., Daniels, J., Evans, W., Fink, W., Krahenbuhl, G., & Saltin, B. (1976). Skeletal muscle enzymes and fiber composition in male and female track athletes. Journal of Applied Physiology, 40(2), 149-154. (Sprinters carry a high proportion of fast-twitch fibers and distance runners a high proportion of slow-twitch — the classic event-vs-fiber-type contrast behind the explosive/enduring lean.)
  • Merkel, D.L. (2013). Youth sport: positive and negative impact on young athletes. Open Access Journal of Sports Medicine, 4, 151-160. (~70-80% dropout by mid-teens.)
  • Bridge, M.W., & Toms, M.R. (2013). The specialising or sampling debate: a retrospective analysis of adolescent sports participation in the UK. Journal of Sports Sciences, 31(1), 87-96.
  • American Academy of Pediatrics, Council on Sports Medicine and Fitness. Sports Specialization and Intensive Training in Young Athletes. Pediatrics (clinical report), 2017.
  • Aspen Institute Project Play (2025). Survey: Family spending on youth sports rises 46% over five years.
  • Robb Report (2026). Meet the Families Betting Big on Their Kids' Athletic Futures (inside the high-cost world of elite youth sports).
  • The Washington Post (2026). The soaring price of youth sports.

This methodology overview is for informational purposes only. Athletic development is highly individual and influenced by many factors beyond what any assessment can measure.