Every young person grows at a different rate. Growth can change movement, coordination, tissue tolerance, recovery and how training feels. Youth OS helps parents and coaches understand that changing context before making training decisions.
Two children of the same age can differ substantially in biological maturation, training experience, movement skill and readiness. A smaller version of an adult program is therefore not automatically an appropriate youth program.
Bones, growth plates, muscles and tendons do not mature at identical rates.
Rapid changes in limb length and body proportions may affect coordination and technique.
Growth information should sit alongside health, pain, sleep, training history, skill and workload—not replace them.
The goal is not to label a child, but to support appropriate challenge, confidence and long-term participation.
PHV describes the period of fastest height growth during adolescence. An anthropometric equation can estimate time before or after PHV, but it is an approximation—not a direct measurement of puberty or injury risk.
Build movement variety, enjoyment, technique and broad physical literacy.
Watch changing movement quality, recovery and emerging discomfort.
Prioritise technique, communication and sensible workload adjustments where needed.
Progress strength and power according to competency, health and training age.
Pain, fatigue, movement, sleep and enjoyment remain more important than one estimate.
Youth OS is intended to help adults notice, discuss and monitor development—not diagnose a child or produce a rigid training prescription.
Understand why a child’s movement, confidence or training response may change as they grow.
Add growth context to observation, communication, session design and workload monitoring.
Two estimates, one purpose: provide understandable context for a young person’s growth journey.
Uses the Khamis–Roche method with current height, weight and biological-parent heights to estimate adult stature without a bone-age X-ray.
Uses the Mirwald anthropometric equation to estimate years before or after PHV from age, standing height, sitting height and weight.
Module 01 performs the calculations locally inside your web browser. V2Fitness does not collect, transmit, store or retain the measurements you enter or the results generated by the tool.
Strong disclaimers support transparency, but they do not replace safe design, accurate claims, appropriate consent or professional responsibility.
V2Fitness and V2 Youth OS do not provide medical advice, diagnosis, treatment, rehabilitation, injury clearance or return-to-sport decisions. Consult an appropriately qualified health professional for concerns about growth, puberty, pain, injury, nutrition or development.
Adult-height and maturity-offset outputs are statistical estimates based on user-entered measurements and published equations. They are not guarantees, direct measures of biological maturity or indicators of future athletic potential.
General training considerations are educational only. Program design must account for health, pain, movement competency, training age, sport demands, workload, supervision, sleep, recovery and the individual child.
PHV does not itself prove that a child is injured or will become injured. The estimate should not be used alone to change training, select talent, exclude participation or delay appropriate clinical assessment.
Start with better growth context—then combine it with observation, communication and qualified professional judgement.
Start Module 01 Free →