Growing Up Fast: PHV and PWV

Youth One Day Match - England Under-19’s v India Under-19’s - The County Cricket Ground, Hove, Britain - June 27, 2025 India’s Vaibhav Suryavanshi in action Action Images via Reuters/Matthew Childs.

"They’re young, they don’t need to rest, they need to work harder." 

This is a common sentiment among coaches and practitioners working in youth sports. Despite significant advances in sports science and evidence-based practice, it’s astonishing that some coaches still cling to this outdated mindset, even while tasked with developing young talent. Why the concern? It stems from the misunderstanding or possible ignorance of the adolescent growth spurt and its profound impact on physical performance and injury risk. 

Adolescent Growth Spurt

Before delving into the specifics, it’s important to define key terms: chronological age, biological age, peak height velocity (PHV), and peak weight velocity (PWV) (see table 1). Chronological age refers to the time elapsed since an individual’s birth. Practitioners and coaches use it to group athletes, identify talent, and set exercise prescription limits⁽¹⁾. However, this method does not account for the significant variation in biological maturation among individuals, which can differ in timing, tempo, and duration – this, in turn, results in early, average, or late maturers, and is not a reliable indicator of skeletal maturity^(2,3). 

Biological age, in contrast, reflects an individual’s physical growth and developmental stage⁽⁴⁾. Biological age requires a valid and reliable assessment method to be a practical alternative in determining player groupings or exercise load. Practitioners use PHV as a biological age indicator and define it as the period during which an individual experiences their fastest upward growth in stature^(5,6).

Peak weight velocity is closely related to PHV, and practitioners define it as the time during which the individual gains body mass at the highest rate⁽²⁾. These milestones differ between the sexes. On average, boys reach PHV at around 13.5 years, growing approximately 9.5 cm/year, while girls reach PHV earlier, at 11.5 years, with a growth rate of about 8.3 cm/year^(2,5,7).

Scientists from Ghent University reported that PWV velocity in boys typically coincides with PHV (around 13.8 ± 0.8 years), with a peak weight gain of 8.4 ± 3.0 kg/year. Findings from the Agharkar Research Institute support this, noting that in boys, PWV occurs at or just after PHV with an average gain of 9 kg/year. In girls, PWV tends to lag approximately six months behind PHV, peaking at around 12.5 years with an average increase of 8.3 kg/year⁽⁸⁾.

Table 1: Definitions

Why Tracking Matters

Periods of accelerated adaptation occur before, during, and after PHV and PWV, with athletes being more sensitive to particular training types⁽⁹⁾. For example, pre-adolescents tend to benefit most from neural-focused training (sprinting and plyometrics), whilst adolescents respond better to a combination of neural and structural stimuli due to the various hormonal changes experienced^(9–11). Despite these periods of heightened sensitivity to specific training modalities, coaches must be mindful of the biomechanical and coordinative challenges associated with PWV and the rapid changes in body dimensions. During these periods, motor control is impaired, which impacts the execution of balance, running, and change of direction tasks⁽¹⁾.

Additionally, inadequate muscular development increases injury risk, such as high-force activities (jumping and landing) that exceed the child’s ability to absorb force. It is for these reasons that coaches need to monitor their players’ PHV and PWV, as they will be able to tailor their training programmes in line with each individual’s biological maturation status and maximize performance while decreasing the injury risk^(1,12). 

“Understanding young athletes’ biological maturity allows practitioners…to make informed decisions…”

When Growth Outpaces Control

Now that there is a clearer idea of what PWV and PHV are, and why practitioners should monitor their athletes, it is important to explore the types, classes, and risk factors associated with injuries in this cohort (see table 2). Understanding the cause of disease and injury is vital in predicting and preventing injury⁽³⁾.

Osgood-Schlatter disease
Practitioners refer to Osgood-Schlatter disease (OSD) as a growth-related injury, and it is the most common growth-related injury around PHV(13). It typically affects males, and four specific variables are the most significant risk factors for developing OSD:

1. PHV age ± six months,
2. The apophyseal stage of the tibial tuberosity, 
3. Quadriceps flexibility exceeding 35°,
4. Reduced gastrocnemius flexibility for six months⁽¹⁴⁾. 

Sever’s disease
Calcaneal apophysitis (Sever’s disease) typically occurs in young active children during growth spurts and is most common during PHV⁽¹⁵⁾.

Musculoskeletal injuries
Musculoskeletal injuries are another common injury during PHV and PWV, with the growth of bones occurring before the increase in muscle mass. As such, there will be an increase in the moments of inertia of the player’s body, which will not be met with sufficient muscle capacity, resulting in muscle strain. Furthermore, tendons increase their cross-sectional area more slowly than their adjoining muscles, resulting in an imbalance between the muscle and tendon, and an increase in overuse-related injuries^(3,13,16). Therefore, clinicians typically advise against early specialization due to the increased risk of overuse injury during this period of musculoskeletal vulnerability.

The adolescent growth spurt, specifically the year before and during, is associated with an increased susceptibility to traumatic injuries. The mechanisms associated with this are temporal skeletal fragility, an increased incidence of acute fractures, and a period during PHV when trunk and leg length have increased. However, muscles must still reach full size and strength (i.e, adolescent awkwardness). The imbalance between strength and flexibility results in a decline in essential motor skills⁽¹⁶⁾.

Patellofemoral pain syndrome 
Finally, patellofemoral pain syndrome (PFPS) is another injury that frequently occurs in young, physically active individuals and seems to arise during puberty⁽¹⁷⁾. The causes of adolescent PFPS are multifactorial, with the PHV-associated contributors being imbalances in muscle and bone development, which exert extra stress on the knee joint⁽¹⁷⁾. 

Table 2: Injury Risk Factors Associated with PHV and PWV^(18,19,20)

Protecting Young Athletes

The primary manner in which clinicians can protect young athletes from PHV and PWV injuries is to monitor their growth patterns and adjust their loads and exercise prescription accordingly^(16,19). During periods of accelerated adaptation, they should focus specific exercises or programs on individuals who are more sensitive to their training effects⁽⁹⁾.

By tracking height monthly, practitioners will gain a clear understanding of whether an individual is entering or experiencing a growth spurt. One specific calculation is the Mirwald equation (see figure 1)⁽²⁰⁾. Once practitioners know an individual’s PHV, they can establish where they sit on the continuum of their biological maturation and what training focus should be applied (see figure 2 and 3).