Measure what matters!

    Using maturity offsets to determine age at peak height velocity

    I came late to the game with biometrics and have only recently been studying and using them to help determine growth stages in young athletes. Most biometric measurements are used in clinical and research situations but some are useful for sport coaches because they can inform training decisions for young athletes. Sport governing bodies can use them to generate statistics about athlete cohorts and estimates for athlete growth.

    One of the calculations, the maturity offset, is used to determine how far away a youngster is from peak height velocity (PHV), the early teen 'growth spurt'. This article will explain how to calculate the maturity offset and how to determine the age at peak height velocity (APHV), an important training milestone.

    Biometric measurements used in determining the maturity offset include height, age, weight, sitting height, and leg length. There are two equations that can be used to calculate the maturity offset, Moore and Mirwald. You can get a complete discussion of the equations here.

    The equations

    Moore equation:

    Female offset = -7.709133 + (0.0042232 x (age x height))

    Male offset = -8.128741 + (0.0070346 x (age x sitting height))

    In the equations below leg length is derived by subtracting sitting height from height; the weight:height ratio is simply weight (kg) divided by height (cm).

    Mirwald equation:

    Female offset = −9.376 + (0.0001882 x (leg length x sitting height)) + (0.0022 x (age x leg length)) + (0.005841 x (age x sitting height)) + (-0.002658 x (age x weight)) + (0.07693 x ((weight/height) x 100)

    Male offset = −9.236 + ((0.0002708 x (leg length x sitting height)) + (−0.001663 x (age x leg length)) + (0.007216 x (age x sitting height)) + (0.02292 x ((weight/height) x 100)

    The Science for Sport website has a spreadsheet tool that uses the Mirwald equations to calculate offsets. It is much easier to use than plugging everything into the equations above. Click here for instructions on how to do the measurements.

    Update 6 October 2018 - Note that the Mirwald male equation does not use the age/weight interaction. This is not an error.

    Update 19 June 2019 - The female Mirwald equation has been corrected. The age/weight interaction should be added rather than subtracted as we had it in the original article. The formula above has been corrected.

    These are predictive equations that rely on accurate measurements and proximity in time to actual APHV. They should be done periodically, for example every four months, as a young athlete ages. Theoretically the result is more accurate the closer the measurements are made to the APHV.

    What do the results mean?

    The maturity offset represents the number of years the athlete is away from PHV. If the offset is negative it means that the athlete has not yet reached PHV. A positive offset indicates that PHV has already occurred. If so, and if the offset is less than 1.5, then it's possible that the athlete is still inside the PHV period.

    To determine APHV simply subtract the offset from the athlete's age at the time the current measurements were made. This is the age at which the equations predict the athlete will reach PHV.

    Age at Peak Height Velocity (APHV) = Age at measurement - maturity offset

    Why is this important?

    PHV represents a period of intense growth. It is typically called the teenage growth spurt but it sometimes occurs prior to the teenage years. It lasts from 12 to 18 months with variation so the period of time an athlete spends in PHV offers a unique training window that does not reoccur.

    Knowing when PHV is likely to occur allows coaches to design training programs that can lead up to this important growth point and then take advantage of training effects available during and immediately after PHV, especially in the cardiovascular and strength areas.


    Bill Price (price@sportkid.asia) is the owner and Chief Data Scientist at Sportkid Metrics.

    DON'T FORGET TO SUBSCRIBE TO THE SPORTKID NEWSLETTER

    Don't miss any content
    Subscribe Now!

    What would you do differently if there were no such thing as talent? - 04 April 2021


    Athlete development measurements and the lingo that goes with them - 21 March 2021


    Retention and Training Age - 07 March 2021


    Fear of missing out is hurting youth sports - 23 October 2018


    Deliberate practice vs. late specialization - 24 September 2018


    Is talent identification even possible? - 17 September 2018


    Who won the Asian Games? - 10 September 2018


    Re-thinking the mission of Malaysia's sport associations - 03 September 2018


    Using maturity offsets to determine age at peak height velocity - 27 August 2018


    The youth sport talent illusion - 13 August 2018


    The tip of the iceberg - 30 July 2018


    7 things youth sport coaches should know - 25 June 2018


    Who is responsible for athlete performance - 18 June 2018


    Creating a culture of achievement in sport - 05 June 2018


    Sport development in the headlines (sort of) - 28 May 2018


    Who won the Commonwealth Games? - 23 April 2018


    Kaizen: Improving sport administration will improve performance - 02 April 2018


    What can Malaysia learn from Norway about sport development? - 05 March 2018


    Dealing with more than one email address and other communication ideas - 26 February 2018


    What can you do to work more efficiently? - 19 February 2018


    LTAD: Training to compete - 22 January 2018


    Sport clubs are the lifeblood of national sport development - 15 January 2018


    Take a chance! - 18 December 2017


    How we calculate age in youth sports can have benefits and consequences - 11 December 2017


    Can bio-banding help reduce the relative age effect in sport? - 04 December 2017


    Understanding the role that intrinsic and extrinsic motivation play in the athlete development process - 20 November 2017


    Great expectations: Expect more, get more! - 14 November 2017


    Why process is more important than outcome in a learning environment - 25 September 2017


    Sport associations are embracing physical literacy training - 18 September 2017


    Creating a true sport development system in Malaysia - 11 September 2017


    Who won the SEA Games? - 04 September 2017


    KL2017: Reporting individual sport results deserved better planning - 29 August 2017


    Can we please forget about ways to identify talent and just work on getting more athletes? - 07 August 2017


    Using the team selection process to boost motivation and increase athlete participation - 24 July 2017


    LTAD: The Train to Train stage - 10 July 2017


    LTAD: The Learn-to-Train stage - 26 June 2017


    Athletic training for youngsters - 12 June 2017


    Visualization and imagery in sports - 05 June 2017


    Young, single-sport athletes suffer more injuries and do not reach their full potential - 29 May 2017


    Transformational vs. transactional coaching - 23 May 2017


    Will they come back tomorrow? - 08 May 2017


    Advice to parents of young athletes - 01 May 2017


    Is VIP leadership of sport associations a good idea? - 22 March 2017


    What happens after an athlete's initial introduction to sport? - 27 February 2017


    "Where do athletes come from?" - 16 January 2017


    Understanding sport talent pathways - 09 January 2017


    Make 2017 the year of the growth mindset - 02 January 2017


    Teaching physical literacy skills in youth sport practices - 12 December 2016


    Developing sport from the ground up - 06 December 2016


    Pay for what you want - 21 November 2016


    The 10,000 hour rule: "Not for the faint of heart nor for the impatient" - 14 November 2016


    Parent involvement in their child's sport participation sometimes backfires - 07 November 2016


    How to do the measurements for determining peak height velocity (PHV) - 24 October 2016


    A foreign coach is not always the answer - 17 October 2016


    Tips on creating an effective coaching environment - 10 October 2016


    Peak height velocity and aerobic development - 26 September 2016


    Early sport specialization is still not a good idea - 19 September 2016


    What kind of data do we need to develop sports? - 13 September 2016


    The attrition and transformation models of sport development - 05 September 2016


    Solve for <x> - 29 August 2016


    Artificial elimination of athletes from training and competition hinders sport development in Malaysia - 15 August 2016


    Time is the most important factor in talent development - 01 August 2016


    What if opportunity never knocks? - 13 June 2016


    The long-term athlete development framework offers youngsters a chance at sport success and an active and healthy life - 06 June 2016


    Early sport specialization is not a good development strategy - 30 May 2016


    What does a declining population mean for sport? - 2 February 2016


    Coaching 'flow' - 11 November 2015


    The coach's role in creating a deliberate practice environment - 02 November 2015


    When should athletes specialize in a single sport? - 11 September 2015


    The Holy Grail of health, wellness, and sport development - 1 September 2015


    Revisiting the 10,000 hour rule - 10 August 2015


    The power of 'not yet' - 20 July 2015


    Let's stop trying to identify sport talent and start developing it - 22 June 2015