Sunday, February 4, 2018

No Evidence that Children Have More Health Risks Running Long Distance Races Compared to Adults

Written testimony in opposition to Proposed Hawaii Senate Bill 2413 that would ban children under 18 from participating in long distance running events

I’m a Doctor of Physical Therapy who graduated from the U.S. Army – Baylor University Doctor of Physical Therapy Program (the top Orthopaedic PT Program in the U.S.) who has been practicing for ten years, and currently have been practicing that past 7.5 years in Hawaii. I’m a Board Certified Orthopaedic Clinical Specialist, a Certified Strength and Conditioning Specialist, and also specialize in slow motion video running form analysis/running form teaching. I have video analyzed over 6,000 runners (ages 11-60+) over the past six years and taught them how to properly run to put less stress on the body and run more efficiently. Furthermore, I’m a high school long distance running coach at Castle High School in Kaneohe. I have been a coach at the Aloha Cross Country Camp for the past seven years, where I have gotten to know hundreds of local Hawaii runners under age 18. I’m the coach and founder of Dr. Nate’s Champion Running Program that focuses on individual coaching for long distance high school runners on Oahu. I help prepare these athletes (14-17 years old) for their cross country and track seasons and for their college running careers. The pillars of my long-distance training program are injury prevention, training all at their individual levels, and teaching young runners how to properly train. As one of the most qualified subject matter experts in Hawaii, if I thought that there was any concrete evidence that those under age 18 are at a greater injury risk running distances over half-marathon, than the rest of the population; I would be the first to support SB2413. However, the subject matter experts in the world and the only studies/data we have regarding minors participating in marathons are in direct opposition of SB2413 and actually demonstrate less health events and risks than the adult population. This is one of many reasons why I’m opposing SB2413. Let’s look at what the top Pediatric experts currently say and then I’m going to give you what I know based on my running, clinical, and coaching experiences over my lifetime.

Section 1 of your bill claims that “the American Academy of Pediatrics’ Council on Sports Medicine and Fitness suggests that sporting activities should be geared to meet the developmental level of children and adolescents in regard to their physical abilities, cognitive capacities, initiative, and interest.” I reached out to one of the leading Sports Medicine Pediatricians in America, Dr. Chris Koutures, MD, FAAP who just completed a six-year elected term as a member of the Executive Committee for the American Academy of Pediatrics Council on Sports Medicine and Fitness, has written 20 professional articles, and is the co-author of the Pediatric Sports Medicine: Essentials for Office Evaluation textbook published by SLACK Incorporated in October, 2013 (see "> for his complete extensive bio). Dr. Koutures states, in regards to distance running for children: “The risks of injury and illness in distance running may be related to the total mileage and number of hours training per week. There is no agreement among sports medicine professionals about distance limitations for children. Until further data are available concerning the relative risk of endurance running at different ages, the American Academy of Pediatrics recommends that if children enjoy the activity and are free of injury or ailments, there is no reason to keep them from training for and participating in such distance events including marathons and half-marathons. Regardless of age, the 10 percent rule is an appropriate guide when designing a training program. - The variables include weekly distance, intensity, and number of training days per week. - Each week, one should only increase one of those three variables, and no more than 10 percent from the previous week.”
Dr. Koutures, like all good physicians, directed me to the best and only research articles and research studies on children running marathons. The studies actually demonstrate no evidence that distance running for those under 18 is harmful or poses a higher risk than the general population. The research shows less health incidents for minors than those over 18 running marathons. Here is the research:

Can Children and Adolescents Run Marathons? Sports Med. 2007;37(4-5):299-301. (Link loads slowly, recommend copy/paste into web browser) (includes statement that American Academy of Pediatrics does not set age guidelines for distance events)

Pediatricians can help young runners stay healthy, avoid burnout. The Official Newsmagazine of the American Academy of Pediatrics. Aug 2013; Vol. 34: 8. (see attached and link:

Youth Marathon Runners and Race Day Medical Risk Over 26 Years. Dr. William O. Roberts et al. Clin J Sports Med. 2010; 20 (4): 318-321. (See attached link for abstract
Dr. Roberts is currently doing further research on runners, under 18, running marathons.
Dr. Roberts’s research shows less health events in minors’ versus adults’ during/after a marathon and this research is further supported with a larger sample size of 846 under 18 running in the 2017 Honolulu Marathon. James Barahal, MD, CEO and Founder of the Honolulu Marathon and President for 27 years states: “I have never even seen a kid in the medical tent. I am a practicing clinician who has seen over 100,000 patients of all ages, although I am not a medical director of the marathon, so it is possible kids have been seen but no one on our medical report team has ever reported an incident with a child running. EVER. Not once (Written conversation 3 February 2018).”

My Statement:

As I outlined above, there is no scientific evidence or studies published that specifically demonstrates that those under 18 have higher risks of injury or heath consequences running marathons. All claims that there is a higher risk of overuse injuries and health complications for those under 18 running marathons are assumptions ‘not’ based on any studies looking directly at under 18 distance runners. Furthermore, the studies and claims cited in section 1 of SB2413 are not conclusive and are not direct research data on children running marathons. I cross referenced the studies in the International Medical Marathon Directors Association (IMMDA) advisory statement and they are outdated articles and textbook commentaries from 1976, 1981, and 1983; not studies looking at children and long distance running. There is no evidence that young long-distance runners have a higher occurrence (than other sports) of osteochondritis dissecans, Osgood-Schlatter disease, or Sever’s disease. I have run long-distance and participated in all the team sports since age 9 and I have NEVER met a young runner or treated a young runner that had osteochonritis dissecans or Sever’s disease. “No studies have linked distance running by young children to potentially serious overuse injuries like growth-plate disruptions or knee arthritis,” says Dr. William Roberts, professor of family medicine and community health at the University of Minnesota and medical director for the annual Twin Cities Marathon ( Furthermore, after a through literature review on knee osteochonritis dissecans and athletes, the incidence is less than 0.025% and the consensus is “the cause is unknown, many theories exist.” (

Additionally, I’ve only met and treated two distance runners in over 25 years that had Osgood-Schlatter’s. Osgood-Schlatter’s is a normal occurrence for ANY young competitive athlete that has to run/jump/squat/lunge repetitively in their sport and that are going through a large growth spurt. Osgood-Schlatter’s will resolve once the young athlete stops growing or sooner. Sever’s disease will resolve after about two months of rest and once again will completely resolve and will not return after the young athlete stops growing.

In regards to the studies that you are referencing that claim children absorb less impact than adults and that their running mechanics may contribute to a diminished ability to absorb shock…these are tremendously flawed studies. First, the article from the Journal of Athletic training that the SB2413 references: concludes, “We do not know how these shock attenuation characteristics are related to overuse injuries.” The study sample size was small n = 18, the age of participants were extremely young 8-11 years old, did not test children that ran long distance races, and most importantly there was no standardization on the type of shoes that the children ran in during the study (the children were allow to us their own shoes, which could have been any type of shoe and worn out). From scientific research we know that a shoe loses it’s ability to absorb impact/shock and actual individual foot strike also matters. For example, runners that heel-strike absorb most of their initial ground shock in their heel (if the shoe has good heel cushion), but if there is not a good shoe heel cushion, then impact forces go up to shin and knee first (increasing injury risk in ALL distance runners). Forefoot and mid-foot strikers absorb most of their initial ground shock in their arch and Achilles tendon (which act as natural springs/shock absorbers).

I read the studies that SB2413 indicates children run with different mechanics, have shorter legs in relation to their body size, and thus ‘may’ have a diminished ability to absorb impact.
A Description of Shock Attenuation for Children Running. 1996.

Is Running Economy Different Between Adults and Children? 1996

These studies are both old, small sample size, and nowhere in the studies do the authors conclude that their findings may contribute to diminished ability to absorb shock or that their findings could result in health outcomes that you are claiming in Section 1 of SB2413. The Bill is making assumptions based on zero date or supportive literature. Fact, the running economy study demonstrated that the children had a higher stride rate, which is actually a good thing for injury prevention. The higher the stride rate, the less ground impact time, then less time the body has to absorb impact and stabilize. Higher stride rate improves running mechanics and causes less over-striding and less heel striking, leading to less impact on the tibia bone, knees, and lower back. The assumptions are similar to how the medical community has assumed for 40 years that those that run will have a higher incidence of knee and/or hip arthritis. We now know that recreational runners, which make up 99.999% of runners, have significantly less knee and hip arthritis than sedentary people. A systematic review of 17 studies with a total of 125,810 people, published in 2017 by the Journal of Sports and Orthopedic Physical Therapy found that: “…only 3.5% of recreational runners had hip or knee arthritis; this was true for both male and female runners. Individuals in the studies who were sedentary and did not run had a higher rate (10.2%) of hip or knee arthritis. Most of the studies the researchers evaluated that showed an increased risk of arthritis from running focused on runners who were at the elite, ex-elite, or professional level [elite running make up only approximately 0.00075% of the running population and they ran over 57 miles/week for years]. These professional or elite athletes or individuals who participated in international competition had the highest rate of knee or hip arthritis at 13.3%.”
(Copy and paste, link does not work directly).

None of the other studies that you cite in your reasoning for SB2413 look at injury rates in under 18 distance runners or take into account what we know now about running form and the forces on your body based on where and what part of your foot strikes the ground relative to your hip joint. It was not until around 2009 that good and conclusive running form and impact studies began to be published. It is my experience doing video analysis, when I compare the recent literature on efficient running mechanics and running form, that younger children generally have better mechanics, and less over-striding (which is directly linked to overuse injuries) than the rest of the population. It is not short legs that lead to injury or diminished impact, but it is first and foremost training too much – to fast (overtraining by increasing running volume greater than 20% per week for consecutive weeks). If you want to link running mechanics/running form to overuse injury, than over-striding (landing greater than 2 inches in front of your hip) and what part of your foot initially strikes the ground first (heel striking) is the most important factor that can contribute to injury if ANY long distance runner is over-training and progresses their running volume >20% per week for over three weeks in a row.

Let’s now address the International Marathon Medical Directors Association (IMMDA) advisory quoted in SB2413 as a reason to prohibit those under 18 to participate in a marathon. The IMMDA explicitly states that “currently there is no scientific evidence that supports or refutes the safety of children who participate competitively in marathons.” However the meeting where they made this statement was in 2008 and they voted to approve their advisory March 2009. This was before Dr. Williams Robert’s full 26-year study was published in 2010 that demonstrated the safety in children participating in marathons. They also completely disregarded Dr. Robert’s preliminary study that was published in 2007 that demonstrated children had less medical events in marathons than adults. As I outlined above, there is much more data and a greater number of children participating now in marathons then there was pre-2008 and it consistently proves the safety of those under 18 running marathons. The IMMDA also quotes, in their advisory, the American Academy of Pediatrics (AAP), “there is no reason to disallow participation of a young athlete in a properly run marathon as long as the athlete enjoys the activity and is asymptomatic.” The two doctors that wrote the IMMDA advisory paper, then go on to directly contradict the consensus of 64,000 Pediatric doctors that are part of the AAP.

I thoroughly read the entire IMMDA advisory statement on children and marathon running. The statement focuses on children that would specialize in marathons as a competitive marathoner and perform specific marathon training year round. If a child was to do this, it would include running over 70 miles per week consistently, which is typical competitive marathon training. However, NO child under 18 in the State of Hawaii is doing this and does this! There is no child marathon clubs or school sports programs or teams for competitive marathon participation. Thus, the ‘burnout’ physically, psychologically, or emotionally that these two doctors are claiming can happen with specializing in a competitive sport year round, is NOT a risk.

In conclusion, since there is scientific and medical evidence that directly opposes SB2413 and absolutely zero scientific and medical evidence that supports SB2413; I once again state my opposition to SB2413. Let the children run!

Very Respectfully,

Dr. Nathan H. Carlson, DPT, OCS, CSCS

Doctor of Physical Therapy Tripler Army Medical Center
Orthopaedic Clinical Specialist
Certified Strength and Conditioning Specialist
Major U.S. Army Reserves and Bronze Star Recipient for work as a physical therapist for one year in Iraq serving over 30,000 and saving the U.S. millions through treating injuries
Founder and Coach of Dr. Nate’s Champion Running Program for high school runners
2-time 1st Hawaiian Resident Finisher and 1st American Finisher Honolulu Marathon
2011 Maui Half-Marathon Champion and 3rd best finishing time ever
Member of the All-Army Elite Cross Country and 10-Miler Teams
33rd place in the 2012 U.S. Cross Country National Championships
Saint Martin’s University Sports Hall of Fame Member for Cross Country and Track
Saint Martin’s University 2004 Assistant Cross Country Coach
2005 NCAA All-American 1500m (8th at the National Championships)
Competed in three NCAA National Track and Field Championships in the 1500m and Mile races.
9-Time Academic All-American (Cross Country, indoor track, outdoor track) and ESPN the Magazine 1st Team All-American
2005 Great Northwest Athletic Conference Sportsman of the Year and Academic Athlete of the Year
Saint Martin’s University record holder 1 mile, 1500m, and distance medley relay
1998 Washington State High School State Champion 1600m and 800m
Husband of 2020 Olympic Marathon Trials qualifier and 4-time Honolulu Marathon 1st Hawaii resident champion: Polina Carlson

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