Why Pediatric Growth Charts Matter in REDs Recovery for Dancers

In the dance world, it can be tempting for dancers to compare their bodies to peers or to a certain arbitrary aesthetic standard, but what is healthy for one dancer may not be healthy for another. So, how do we determine what a healthy body looks like for an individual dancer?

When I see a patient with Relative Energy Deficiency in Sport (REDs), even if they are now adults, one of the most helpful resources I rely upon is their pediatric growth charts. Growth charts tell the story of an individual’s history of growth and development over time, and can often help us better understand the weight and BMI percentile range where their body historically functioned best.

We know that BMI is far from a perfect measure but any rise or fall in BMI percentile for an individual can be an indicator that a medical condition such as REDs or an eating disorder might be at play and warrant further investigation. 

After early childhood, most people tend to track along a certain percentile line for height, weight, and BMI. While some variation is normal, in general, most have a certain percentile range at a given age where their body is healthiest and most resilient. Generally, this corresponds to the percentile of BMI where they tracked prior to the onset of REDs. The BMI number where a dancer’s body is “happiest” tends to increase over time until the 20s, which is normal and expected during adolescent growth and development. This is due to various factors, including added height, increased lean mass, and additional bone density. 

In order to better illustrate the value of growth charts in REDs recovery, let’s look at two fictional case examples:

Case 1

Dominic used to track around the 25th percentile of height, weight, and BMI between ages 8 and 14. At 15, he started dancing more seriously. Now at age 20, his weight has not changed since 15, though he did grow a couple more inches. He is struggling with decreased libido and low testosterone (determined by labs), recurrent injuries, and fatigue. Even though he’s now an adult and his weight hasn’t changed for years, Dominic’s BMI percentile has decreased to the 10th percentile due to added height and being older. His pediatric BMI charts reveal that he is weight suppressed, which is likely why he’s struggling with REDs today. In order for Dominic to regain energy, normalize his hormones, and perform his best, he will likely need to increase his BMI back to at least the 25th percentile for a 20 year old (most pediatric growth charts stop at age 18-20, but can be informative even for those over this age). 

His case highlights an important point: a weight that was appropriate at age 15 may no longer be adequate at age 20.

Case 2

Daphne was previously tracking along the 80th percentile in height and 50th in BMI until age 13, when she increased her dance training substantially. Now at age 15, she’s in the 60th percentile in height and 20th in BMI. She has not yet had a menstrual cycle and is recovering from a stress fracture. 

Conclusions

Although other medical causes should always be considered, this type of downward shift in both height and BMI percentiles, in addition to her bone stress injury, raises significant concern for low energy availability and REDs.

In both cases, Dominic and Daphne technically remain within a “normal” BMI range. Without access to their historical growth charts, they might even be told that their weight is normal.

However, growth charts provide essential context as both dancers have deviated substantially from their own long-term growth trajectories. That pattern is not considered typical and may indicate inadequate energy availability during critical periods of growth and development.

Ideally, growth chart data is being collected and monitored in a confidential manner by a healthcare professional, like a pediatrician, general practitioner or in house physical therapist or medical provider. 

It is recommended that young dancers’ height and weight are monitored routinely by trained healthcare professionals in a sensitive and confidential manner. This helps ensure healthy growth, allowing each dancer to reach their peak height and growth velocity while training. Decisions on dance training load based on BMI alone are not generally recommended without any other further investigation and context. Coaching/training staff monitoring weight, height, and BMI is never recommended.

One dancer may be fully nourished and healthy at the 5th-10th percentile, whereas another may be undernourished and at risk at the 75th percentile if they previously tracked higher on the curve. Again, the overall context and the individual’s personal history matters much more than the absolute BMI number. After all, it’s not possible to know if a dancer has REDs just by looking at them.

One practical way to recognize a potentially concerning change is to look at the bold percentile lines on pediatric growth charts (corresponding, for example, the 5th, 10th, 25th, 50th percentiles, etc). After early childhood, any deviation upward or downward in height, weight, or BMI percentiles generally warrants further medical evaluation. Growth charts also provide excellent context for understanding a dancer’s health status as a whole, which can prompt important healthcare discussions.

A change in growth trajectories also help provide important context for better understanding your child’s overall health and fueling patterns, as well as a starting conversation for supportive healthcare discussions. 

Growth charts aren’t about judgment, they’re about recognizing any changes in growth trajectories, while providing essential data and context for understanding a young dancer’s health and fueling patterns. A dancer’s growth trajectory may also help identify when additional support may be needed for them to grow, develop, and thrive. 

Written by Katherine Hill, MD, Pediatrician, REDs medical specialist, & Cofounder @ AthleatMD