How Late is Too Late for Your Child’s Bone Health?

  • October 11, 2017

When the bell rings signifying the end of the school day throughout Hayward Unified School District, hundreds of students across the city flock to cafeterias, recess yards and multipurpose rooms for HUSD’s Youth Enrichment Program. The program functions as both after-school care for working families and an extended learning opportunity for kids, which the school district has seized upon to work in lessons on healthy eating, exercise and lifestyle choices.

This year, through a federal grant from the Corporation for National and Community Service, AmeriCorps National Civilian Community Corps, Hayward schools have partnered with Cal State East Bay Associate Professor of Kinesiology Vanessa Yingling, who is leveraging her own research to put a special spin on the after-school program: she’s focusing on bone health.

“Kids can’t see their bones the way they can see their muscles, so it’s a hard sell,” Yingling says. “But we know that later on in life, when a person breaks a hip, there’s a high incidence of death within the next year. And there’s research to suggest that kids who fracture bones become adults with lower bone mass and an increased risk of fracture. Osteoporosis is a pediatric disease with geriatric consequences — I can’t take credit for being the first to say that, but it’s true.”  

According to Kristal Brister, field coordinator for HUSD’s “Viva Bien, Coma Bien, Siéntase Bien!” (Live Right, Eat Right, Feel Right) AmeriCorps program, there is a particular urgency for sharing Yingling’s knowledge with children and families in the local community.

“The VCS! AmeriCorps grant was first received by Hayward schools from 2010-13 because Hayward has the highest incidence of overweight and obese children in Alameda County,” Brister says. “And it’s why we received continued funding again in 2016. It’s really important that we focus on healthy eating and active living for our local students and families.”

For Yingling, combatting obesity is a critical challenge for all kinesiologists, and she wants to drive physical activity toward games and exercises that not only promote a healthy lifestyle, but bone health specifically.

“If you sit on the couch, your bones will become good at sitting on the couch. If you exercise your bones will adapt to that stress.”

“The majority of a person’s bone growth takes place during the pre-adolescent and adolescent years,” she says. “If you sit on the couch, your bones will become good at sitting on the couch. If you exercise your bones will adapt to that stress. So adolescence is the time when we need to be really focused on helping kids develop strong bones that will support them for the duration of their lives. If we miss this window, an opportunity is lost.”


It’s a problem up to 55 million Americans may wish they could turn back the clock on. According to the National Osteoporosis Foundation, an estimated 10 million adults in the United States have osteoporosis and another 44 million have been diagnosed with low-bone density, putting them at a higher risk of bone fractures and breaks. Importantly, bone fractures and breaks are also associated with a range of devastating co-morbidities — related infections, conditions and physical injuries that lead to poorer health, decreased quality of life and earlier death in the long run.

Yingling’s answer is not only to get kids and their families thinking about bone health through nutrient-rich foods and encouraging them to play dynamic games and sports that put stress on the bones, and thus promote growth, but to integrate the importance of bone health into physical education curriculum throughout the United States.

“FitnessGram is the national organization that disseminates testing for kids in physical education — the sit-ups, pull-ups and flexibility tests that kids do to measure their fitness each year in elementary school,” Yingling says. “And they care very much about bone health and promote it in their literature, but there isn’t actually a physical test that corresponds to measuring a child’s bone health included within the FitnessGram program. It would be amazing to have that.”

In order to come up with a solution for what that test might look like, the professor turned to the campus community at Cal State East Bay.


Traditionally, in order to measure bone strength and quality, Yingling explains, you need a scanning machine, which is the most precise and reliable way to look at the components that contribute to a person’s bone strength: how much bone you have, the density and the distribution (thick rather than narrow).

But those scans are expensive and typically only used when a bone is broken or a child displays signs of developmental delays.

“Bone scans will simply never be used as a screening tool in children the way we screen for the health of other things, like vision and hearing,” Yingling says. “The radiation from the machine is very low, but it scares people, and it’s just a device we think of as limited to specialty use.”

With that in mind, Yingling began thinking about the relationship between muscle and bone, and a physical test that might be used as a substitute for a scan. For the past few years, she’s been tapping her students to run studies on the Cal State East Bay population comparing various muscle function tests (hand-grip strength, leg extensions, vertical jumping) to the results of bone scans performed in the kinesiology lab’s state-of-the-art peripheral quantitative computed tomography machine — pQCT for short.

The end result?

“We found a strong correlation between a person’s bone strength and their peak power,” student Rebekkah Reichert, a co-lead on one of two studies explains. “The participants with strong vertical jumps nearly always had higher bone strength.”  

The beauty of that outcome for Yingling, forthcoming in the Journal of Strength and Conditioning, lies in its simplicity.

“Kids [jump] naturally — they intuitively know how to optimize their bone,” she says. “And the whole idea of how high you can jump gets into how fast your muscles contract. We’re talking about muscle power and velocity, which has a stronger relationship to bone strength than muscle strength tests alone. High-impact activities that have a dynamic impact on the body, like jumping, turn out to be a great stimulus for your bones.”


In collaboration with Assistant Professor Jennifer Sherwood and an Oakland-based nonprofit called American Bone Health, Yingling has developed curriculum for VCS! AmeriCorps to start integrating in the HUSD afterschool programs, and also seminar material for two different parent workshops that are a part of the Healthy Eating Active Living Family Workshop Series supported by Kaiser Permanente Community Benefit Program of Southern Alameda County.

Alongside Sherwood, Yingling will be teaching parents about the nutrition and exercise their children need to develop strong bones during the critical growing period, and VCS! AmeriCorps volunteers will be focusing on integrating what Yingling calls “bone overlays” — questions, lessons, and sports and games that deliberately include jumping to raise kids’ awareness levels.

Yingling also has some boots on the ground at local Harder Elementary School. New alumnus Andrew Denys (B.S. ’16, Kinesiology), who is also a new lab technician at Cal State East Bay, co-led the study alongside Reichert. Through outreach on campus, Denys applied to VCS! AmeriCorps, and has signed on for 900 hours of service through the organization, starting with the after-school enrichment program in Hayward.

“Campaigns like  ‘Got Milk? ’ are interesting because of the attention they bring to bone health, but they’re oversimplifying what we need to do to create strong bones.”

“Kids are little sponges,” Denys says. “We’re going to be focusing on physical activity and nutrition, and I think as long as I can make it fun, they’ll get excited about being active. And I’m looking forward to trying out some new things with them. I’ve already noticed that with some sports the girls don’t want to play and they sit down instead of engaging, so I’m thinking about bringing in some old school jump rope, double-dutch style games that appeal to them. I want to get them jumping.”  

It’s only the beginning of a much longer and wider road for Yingling, who hopes to make the leap to physical education classes and FitnessGram in the coming years — but it’s a strong start.  

“It’s important to me for people to understand that we’re not saying, ‘Your vertical jump is low, you have bone problems,’” she says. “We’re saying, ‘Whatever activities you can do to improve your vertical jump may also increase your bone strength.’ And I’m really passionate about not pitting exercise and nutrition against each other. Campaigns like ‘Got Milk?’ are interesting because of the attention they bring to bone health, but they’re oversimplifying what we need to do to create strong bones. I don’t want to sacrifice truth for complexity — I think people can handle the whole picture.