1. New Insights into Injury Prevention in Elite Youth Tennis
Neeru Jayanthi, M.D. Associate Professor Orthopaedics and Family Medicine Director Tennis Medicine Emory University Sports Medicine Center
President, STMS
STMS-Web.org

2. Tennis Injuries?

3. OBJECTIVES
Identify different research study designs in evaluating junior competitive tennis players
Formulate appropriate evidence-based tournament, training, and match volume injury prevention recommendations
Introduce individual risk reduction strategies and areas for future research

4. INJURY PREVENTION
No known interventional study on injury prevention in junior elite tennis players!

5. Parental/Coach Influence on Training
Elite British young athletes (soccer, tennis, gymnastics, swimming)
Most powerful influence to do intensive training: (TENNIS ONLY)
1. Coach (45%)
2. Child (35%)
3. Parent (15%)
Baxter-Jones, Mafuli, J Sports Med Ph Fit, 2003

6. Training profiles of US Junior Elite
Median hours/week training
11-25 tournaments/year
70% specialized in tennis
Mean age 10.4
Jayanthi et al, Journal Med Sci Ten 2009

7. US JUNIOR TENNIS
We have no self-regulation of injury risk in US junior tennis
There is a volume-based point ranking system

8. Quantifying Injury Risk
LEVEL OF RISK
RISK OF ATHLETE
RISK OF INJURY
SPORTS PARTICIPATION
HIGH
SPECIALIZED
HIGH VOLUME >10-16 hrs
HIGH COMPETITION
PRIOR INJURY (back)
RAPID GROWTH
OLDER, MALE
>4th match in tournament
SPONDYLOLYSIS STRESS FRACTURES
GROWTH PLATE
OCD
RESTRICT
INTERMEDIATE
LOW SPECIALIZE
INTERMEDIATE GROWTH
INTERMED VOL.
APOPHYSITIS
APOPHYSEAL AVULSIONS
INSTABILITY
TEMPORARY RESTRICTIONS OR REDUCE
LOW
MULTIPLE SPORTS
RECREATIONAL
LOW VOLUME
STATIC GROWTH
PATELLOFEMORAL
MUSCLE STRAIN
TENDONITIS
MINIMAL RESTRICTIONS, AS TOLERATED

9. Injury Prevention Recommendations
Within a tournament
Annual match/tournament volume
Competition
Weekly volumes
Off court injury prevention
Specialization
Training
Strokes
Biomechanical risks
Screening
Individual risks

10. Study Designs Descriptive epidemiology Cross-Sectional
Analytical-Case Control
Case Series/Individual Factors
Biomechanical analysis

11. Epidemiology
Injury rates have been documented in competitive junior tennis players:
Jayanthi
Hutchinson
Safran
Reece
De Silva
Hjelm
Kovacs
Hashimoto

12. Population - Based Descriptive epidemiology (Trends) Risks:
Safran (USTA)
Hutchinson (USTA)
Silva (Brazil), Hashimoto (Japan)
Jayanthi (USTA) (medical withdrawals)CROSS-
Kovacs (USTA)
Risks:
>5th tournament match
Boys similar to girls injury rates
Injured boys 1000 hrs/year

13. Injury Rates-Tournaments
21.5/1000 AE
Hutchinson (1440 players, 16 and under boys)
35/1000 AE
Safran (Girls 14’s and 16’s,players)
(6.9 med treat/1000 games)= 140/1000 AE (matches)
Silva (12-18 y/o)

14. Injury Locations-Tournament
Back
Thigh
Shoulder
Hutchinson et al.
We need to understand relationship of tournament volume better

15. 28,336 match exposures analyzed
RISK FACTORS FOR MEDICAL WITHDRAWALS IN USTA JUNIOR NATIONAL TENNIS TOURNAMENTS
28,336 match exposures analyzed
Sex (Males inj>females)
14,108 male 14,105 female
Age
7,056 in 12’s 7,002 in 16’s
7,184 in 14’s 7,094 in 18’s
Jayanthi et al, 2009

16. Results: Match Volume & Medical Withdrawal Incidence
P<0.0001

17. MATCH SCHEDULING
Cumulative match volume may be detrimental to young tennis player.
We need to consider recovery in scheduling

18. SAME DAY COMPETITION
24 youth athletes did not recover physiologic strain and perceived effort with one hour rest in between two 80 minutes cycling sessions in LAB (ideal environment)
Bergeron, et al., 2009.
14 and under boys afternoon match winner predicted based on opponent’s minutes exposed to heat prior to match.
Coyle, et al. 2006

19. Between-contests rest
Sport
Competition load
Between-contests rest
Tennis
3 singles, 2 doubles matches/day
1 h (singles), 30min (doubles)
Bergeron, Michael, “Youth Sports in the Heat: Recovery and Scheduling Considerations for Tournament Play”, Sports Med, 2009.

20. Tournament Recommendations
Exercise caution in junior tournament players competing in their fifth match and beyond, particularly in older age divisions (SORT Level B)
Reduce size of some tournaments to Round of 32 or 64

21. Tournament Recommendations (Same Day)
Consider having at least 1-2 hours between same day matches to allow for sufficient recovery. (SORT Level B)
Cancel consolation for extreme heat conditions

22. Prospective Evaluations
Analytic-Case Control (Evaluate Specific Risk Factors)
Hjelm et al. (Sweden)
Jayanthi (US)
Hashimoto (Japan)
Baxter-Jones (U.K.)
Risks:
Prior Injury (back)
>10-16 hrs/week
Sports Specialization

23. Prospective Evaluations
Hjelm (Sweden)
Ruiz-Cottaro (retrospective)
55 players over 2 years
2.3 inj/1000 hr (boys)
Risk factors for injury:,
Previous injury (OR, 8.8), p=0.01
> 6hrs/week for back (OR 4.7), p<0.04
Total hrs/year (p=0.02) 446 hr/yr versus 246 hr/yr
66 cases of spondylolysis
Spanish Tennis Federation
>15 hours/week in all cases

24. Training and sports specialization risks in junior elite tennis players
Neeru Jayanthi, MD
Amanda Dechert, MS2
Amy Luke, PhD
Ramon Durazo-Arvisu, PhD
Loyola Stritch School of Medicine

25. Design: Prospective cohort study
Methods
Design: Prospective cohort study
540 players consented
519 sufficiently completed baseline survey
498 did NOT medically withdraw
21 medically withdrew
After IRB Approval & Informed consent, we distributed surveys to the players. Those that withdrew were given post-match evaluations to determine the reason for their withdrawal
Summer Tournament Play 25

26. “Training and Sports Specialization Risks in Junior Elite Tennis Players,” Jayanthi, Dechert, Luke et al.

27. Months/Year Competing

28. Results Players who specialize only in tennis
Increased medical withdrawal
risk and:
Players who specialize only in tennis
(p = 0.047)
Players who have had an injury or illness in the past year
(p < 0.001) (5.4x increase)
Playing >16 hours week may be risk factor for development of medical withdrawal

29. Training Recommendations
Caution when playing >10 hours/week history of prior injury, particularly in the low back and before a tournament (SORT Level B).
Hjelms, Kovacs, Jayanthi et al.
Participate in less tennis hrs/week then your age to prevent overuse injury (SORT B)
Jayanthi, et al.

30. Risks of Sports Specialization and Rapid Growth in Young Athletes
Uninjured (sports physicals)
Uninjured
1191 athletes
150 tennis players (12% of all athletes)
91 specialized tennis players (61%)
Jayanthi et al., 2014
Injured (sports medicine clinic)
Injured

31. `

33. Begin intense training before age 12 Specialize before age 12
Study
Sport(s)
Athletes
Evidence for (+):
Study conclusions
Begin intense training before age 12
Specialize before age 12
Begin intense training after age 12
Diversify early, specialize after age 12
Hume
Rhythmic gymnastics
106 across all levels +
Amount of gymnastic training during development is related to level of attainment. All gymnasts participated in other sports, with no difference between elites and sub-elites. Enjoyment of gymnastics was strong predictor of attainment.
Law
6 elite sub-elite
Elites and sub-elites began intense training at similar ages, but elites were involved in fewer other activities from age 4-16, and accumulated more hours training by age 16.
Helsen
Men’s' soccer, Men’s' field hockey
33 international national provincial
Soccer began practicing at age 5, field hockey at age 9. Hours spent in practice were similar among levels until age 12. After age 12, international players spent more time in practice than national players, and national players spent more than provincial players.
Hodges
Wrestling
21 elite club-level
Elite wrestlers spent more time training after age 16 compared to club-level wrestlers. However, since all subjects began intense training at yrs, comparison to early intense training (before age 12) not possible.
Soberlak
Men’s' ice hockey
4 elite
Elite players intensified their deliberate hockey training in late adolescence and played other sports during developmental years
Carlson
Men's and women's tennis
10 elite near-elite
Elite players began intense training and specialized later (after age 13-15) than near-elites (age 11).
Lidor
Various men’s' and women’s' sports
63 elite near-elite
Elite more likely than near-elite athletes to begin intense training after age 12 and to have played >1 sport during developmental years.
Gullich
Olympic sports
1558 German athletes from Olympic promotion programs
Elite athletes began intense training and competition in their sport later than near-elites (11.4 yrs vs 10.2yrs and 13.1 vs 12.0). More elites participated in >1 sport from age 11 than near-elites (64% vs 50%).
Moesch et al
Sports measured in cms, gms or secs*
148 elite near-elite
Elite athletes began intense training at a later age compared to near-elites. Near-elites accumulated more hours of training by age 9, 12 and 15 than elites, while elites accumulated more training by age 21 than near-elites.
Baker et al
Men's and women's field hockey, Men's basketball, Women's netball
15 elite near-elite
Elites accumulated more hours of sport-specific practice from age 12 years onwards. However, all subjects began intense training at about age 12, so unable to compare to an early intense training group. Elites had broader range of sports experiences throughout their careers compared to near-elites.
Barynina 19926
Men's and women's swimming
Elite Russian swimmers (number not reported)
Swimmers who began specializing before 11 yrs of age spent less time on national team and retired earlier than later specializers.
Wall
Boys' ice hockey
Parents of 8 minor league players (mean age 13.9 yrs) and 4 ex-minor league players (mean age 14.5 yrs)
Dropouts began off-ice training earlier than non-dropouts (11.75 vs 13.8 yrs of age) and spent more hours in off-ice training (107 vs 6.8 per year). Both groups participated in a similar number of other sports (4.75) from 6-13 yrs of age.
*Canoeing/kayak, cycling, orienteering, rowing, sailing, skiing, swimming, track and field, triathalon, weightlifting

34. FACTORS FOR ELITE SUCCESS
Elite Soccer players
More unstructured free play between ages 6-12
Elite Tennis Players
Same Coach
Less overall demands for success

35. Defining Sports Specialization
Intense Year Round Training in a Single Sport at the exclusion of other sports
Jayanthi et al., DiFiori et al.
Year round training/competition> 8 months)
Choose a main sport
Quit all other sports to focus on one sport

36. Rates and Degrees of Specialization
38%
34%
Jayanthi, et al.

37. Jayanthi, et al. % Low specialized 47.7% 34.4% 38.2% p<0.001
Uninjured
(N=368)
Injured
(N=822)
Total
(N=1,190)
P-value
% Low specialized
47.7%
34.4%
38.2%
p<0.001
% Moderately specialized
30.7%
34.9%
33.7%
%Highly specialized
21.6%
28.1%
Jayanthi, et al.

38. Sports Specialization Training Risks

39. Competitive Tennis players
14.7 ± 1.9 yr
89.0% injured (81/91)
Specialization Score 2.6 ± 0.6
Total hrs: 17.7 ± 6.1 hrs/wk
Tennis: 12.5 ± 5.1 hrs/wk
Free/rec: 2.8 ± 3.3 hrs/wk
Sports training ratio: 4.5
Main sport tennis (N=91)
13.1 ± 2.4 yr
77.3% injured (45/59)
Specialization Score: 1.8 ± 0.8
Total hrs: 17.1 ± 7.6 hrs/wk
Tennis: 9.1 ± 4.6 hrs/wk
Free/rec: 5.1 ± 4.7 hrs/wk
Sports training ratio: 1.8
Diversified Tennis (N=59)

40. Specialization Recommendations
Consider delaying specialization in tennis until middle or late adolescence for injury prevention as well as for successful performance (SORT Level B)
There may be a risk of early specialization in tennis.
Consider delaying specialization beyond pre pubescent ages.
Reduce your sports training ratio <2:1

41. Injured Tennis Players
3 months: (1-15)
12 months: (2-47)
Mean tournaments:
3 months: (2-42)
12 months: (3-136
Mean matches:
(p=0.01).
Jayanthi, et al., unpublished

42. Tournament Volume Recommendations
Annually, consider playing <40 competitive SINGLES matches/year
Consider 1-2 tournaments/month (SORT C)
Broken down by age, significant in 18’s

43. Training for success
Retrospective review of top 10 men’s players and mean number of tournaments
17 y/o = 11.0
18 y/o = 15.2
Reid M et al. 2009
Successful elite players
Train less <15 y/o
Have same coach
Fewer demands for success
Carlson, et. al. 1985

44. Individual Risks Physical evaluations (strength, flexibility)
Ellenbecker
Roetert
Kovacs
Hjelms No clear link to injury risk
Injury Risks
Jayanthi Risk of sports specialization
Hjelms Risks with low back
Stroke Evaluations
Gomez
Kibler
Fleisig Can have increased loads/stress shoulder/elbow
Abrams/Safran Can have increased loads/stress shoulder

45. Asymmetric Tennis Player
Structural Evaluations
Asymmetric tennis player
GIRD
Wrist, forearm
Rectus, iliopsas
Ellenbecker, Roetert, Hjelm, Kibler, Baxter-Jones, Cools/Johannsen assessments
Unclear relationship to injury
Can improve GIRD (Kibler)
Serial MRI’s lumbar spine
85% with abnormalities
Spondylolysis
Turner, et. al

46. Serve-Kinetic Chain
Leg Drive-->Trunk rotation-->Rapid shoulder internal rotation-->Forearm pronation-->wrist flexion-->Arm adduction
Legs/trunk: 54%
Shoulder: %
Elbow: %
Wrist: %
From Kibler, WB,1995

47. Stroke changes and injury risk
Upper Extremity
Lumbar spine
There is no known interventional study testing biomechanical changes and injury risk in junior elite players!
Jayanthi, Esser, CSMR, 2013

48. Biomechanical Risks 13 yr old appropriate age for kick serve (SORT C)
Increased lumbar spine forces
Kick serve places higher demands on the low back and shoulder
Abrams
More shoulder and elbow stress with limited knee bend (<10 degrees)
Fleisig, et al.
Recommendation: Delay kick serve until after age 13 to reduce stressful loads (SORT C)
Kovacs, Abrams

49. USTA 4: Evaluation of Junior USTA Players Injury Risk Using a Novel Weekly Electronic Survey
Neeru Jayanthi, MD, Calloway Robertson MS2,
Lara Dugas, PhD
Loyola Stritch School of Medicine

50. STUDY DESIGN
16 elite junior competitive tennis players (13 F, 3 M) completed baseline survey
Complete weekly electronic survey x 10 weeks during tournament season

51. Training volume and risk of injury
Higher weekly training volumes in uninjured players (14-15 hrs/wk vs hrs/wk)
(p<0.010)

52. USTA 4-Results
Those that had lower off court training (1 or less hrs/week) were more likely to get injured (p<0.067)
May be protective of higher volumes of tennis
Consider >1 hour at least of off court training/injury prevention

53. 10 and under tennis
What effect will this have on cumulative volume in the next generation of elite juniors?

54. Ideal Training Program
12 y/o junior tournament player
< 12 hrs/week
<12 tourn/yr
Possibly consider another sport (soccer) with an off-season for tennis
2+ hrs/week injury prevention training, etc.
THIS IS NOT POSSIBLE IN CURRENT RANKING SYSTEM TO MAINTAIN A HIGH RANKING

55. Summary of Recommendations
Exercise caution in junior tournament players competing in their fifth match and beyond, particularly in older age divisions (SORT Level B)
Reduce size of some tournaments to Round of 32 or 64
Consider having at least 1-2 hours between same day matches to allow for sufficient recovery. (SORT Level B)
Cancel consolation for extreme heat conditions
Caution when playing >10 hours/week history of prior injury, particularly in the low back and before a tournament (SORT Level B).
Participate in less tennis hrs/week then your age to prevent overuse injury (SORT B)
Consider delaying specialization in tennis until middle or late adolescence for injury prevention as well as for successful performance (SORT Level B)
There may be a risk of early specialization in tennis.
Consider delaying specialization beyond pre pubescent ages.
Reduce your sports training ratio <2:1
Annually, consider playing <40 competitive SINGLES matches/year (SORT C)
Consider 1-2 tournaments/month (SORT C)
Recommendation: Delay kick serve until after age 13 to reduce stressful loads (SORT C)

56. FUTURE RESEARCH
There are no interventional injury prevention studies in junior tennis players
Tournament scheduling (recovery)
Same day matches
10 and under tennis
Transition balls
Growth
Attrition
Specialization

57.                  
IOC WORLD CONFERENCE PREVENTION OF INJURY AND ILLNESS IN SPORT
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