school of medicine - u of u school of medicine ......–bearing hardship; staying power, continuity...
TRANSCRIPT
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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
R a u h M J , M a r g h e r i t a A J , e t a l . 2 0 0 0
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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