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CHILDHOOD ENDURANCE ATHLETES: HAVE WE GONE TOO FAR?

JOY ENGLISH, MD, RMSK

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BACKGROUND

• Childhood athletic population steadily growing– Organized sports

• 45 million– HS XC athletes

• 2003 – 364K• 2008 – 429K• Female XC athletes -

most at risk population, overuse injuries1

• Paucity of literature

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• Child– <18 yo

• Endurance– Bearing hardship; staying power, continuity or

lastingness

• Athlete– A person who is trained or skilled in exercises,

sports, or games requiring physical strength, agility, or stamina

Childhood Endurance Athlete: An individual <18 yowith the staying power to participate in sports

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BUDHIA SINGH

• Youngest person to finish a marathon (2005) – Age 3

• 48 marathons by age 4

http://blog.theclymb.com/out-there/4-children-ultra-running-phenoms-you-havent-heard-ofyet/

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COLBY WENTLANDT

• Youngest person to complete a 100-mile race – Age 12– ‘Ride the Wind’ near Red

Rocks Canyon– Elevation gain of 7k feet

http://blog.theclymb.com/out-there/4-children-ultra-running-phenoms-you-havent-heard-ofyet/

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NICKADEMUS HOLLON

• Youngest person to finish the BadwaterUltramarathon – Age 19– 135 miles– Elevation gain of 13k feet– In Death Valley

http://blog.theclymb.com/out-there/4-children-ultra-running-phenoms-you-havent-heard-ofyet/

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So…What do we know?

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CONSIDERATIONS

• Anatomic• Physiologic

– Defining ”Normal”• Biomechanical• Nutritional• Mental/Psychologic

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ANATOMIC CONSIDERATIONS

• Immature cartilage more susceptible to shear force– OCD

• Muscle bone growth asynchrony – Apophyseal disorders

• Repetitive trauma to the hip growth plate may cause early OA (FAI)

• Traction apophysitis –Sever’s, Osgood-Schlatter, etc

• Predisposition to injury because of decreased flexibility

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HEAT/COLD INTOLERANCE

• Greater BSA: mass– Gain more heat on hot days, lose it on cold

days• Poor ability to dissipate metabolic heat

– Produce more metabolic heat/unit of body mass

– Lower sweating capacity• Longer to acclimatize to heat or cold• Poorly convey heat from core to skin

surface via blood

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• 57 athletes vs 37 controls• Physical Exam, ECHO, EKG

– Baseline• Athletes - lower RHR, incomplete RBBB (19%), TWIs in V1-V3 (0)• Controls – higher RHR, incomplete RBBB (15%), TWI in V1-V3 (6%)

– 5 months• further decrease in RHR, no changes in incomplete RBBB, TWI in

controls lessened to 3% (likely related to change in Tanner stage)

• Conclusion– No significant EKG changes to suggest exercise-induced

morphologic remodeling despite physiologic increase in cavity size

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• 57 athletes vs 37 controls• Physical Exam, ECHO, EKG

– Baseline• no differences in indexed RVOT & RV basal EDD

– 5 months• swimmers significantly increased indexed RVOT and RV

basal EDD– Normal RV function, no change in RV fractional area

• Conclusion– ”Endurance training influences the heart of growing

preadolescent athletes with an increase in RV dimension with preserved function. It is a physiological expression of the athlete’s heart and not incipient RV cardiomyopathy”

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• 7 athletes vs 39 controls– Doppler Echo & gas exchange

• Conclusions :– SV critical determinant of VO2max

– Factors that influence SV are important for defining VO2max differences b/t trained & untrained children

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PHYSIOLOGIC CONSIDERATIONS

• Increased risk for heat/cold illness• Defining childhood athlete’s heart

– Increased in RV dimensions with preserved function– No EKG changes even in light of altered RV dimensions

• Maximal stroke volume is the critical determinant for VO2max– Factors that influence SV are important for defining VO2max

differences b/t trained & untrained children

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BIOMECHANICAL CONSIDERATIONS

• Walking (all-comers)– GRF = 1 x BW

• Running (all-comers)– GRF = 2-3 x BW– 500-1000 steps on each leg/mile– Most injuries in marathoners are overuse

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• 11 boys, 7 girls (N = 18)• Eval’d shock attenuation

– Measured head/leg peak impact in 4 conditions – TM (3 speeds) and OG• Avg 60% (boys > girls)• Studies suggest adults attenuate at 80-90%• Better for boys at higher speeds• Better on OG than TM

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PSYCHOLOGIC CONSIDERATIONS

• ESS associated with negative psychologic effects– Neg effects on schoolwork– High rates of ‘psychological dissatisfaction’– Neg effects on families enjoyment of their sport

• Instead:– Focus on psychologic well-being of the child– Child-driven not parent-driven or coach-driven– Emphasis on enjoyment and fitness, not competition

1. Blankson KL, Brenner JS 2016

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What does real-time data suggest?

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• 9 male runners, avg age 12• Ran 4-km

– Weight, resting EKG, echo, maximal cycle test w Doppler echo at 3 time points • 4 days pre-race, immediately post-race, 24-hr post-race

• Results– Immediately post-race

• Mean decrease in BW, Mean decrease in LVEDD, No changes in shortening fraction -> c/w dehydration

– 24-hours post-race• NL peak work capacity, max SV, max CO

• Conclusion – no adverse cardiac effects

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CONCLUSION

• Known risk factors for childhood athletes including– Heat illness, injuries to the cartilage, apophyseal injuries – current

and future

• Beginning to recognize normal physiology for childhood athlete heart – unknown long-term implications

• Real-life data says:– No increased serious race day risks (1/2 of adults)– Increased risk for overuse injuries

• Some studies suggest that running has the highest overuse injury rates

• Early sport specialization studies suggests burnout and poor performance

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I RECOMMEND:

• Must be individualized– Injury rates and severity of injuries differ b/t

sports– 5 vs 18

• Okay, if:– Participating injury-free– The child enjoys it and does not feel external

pressure to compete