Sweden is a great tennis
country
Empiri on injuries in tennis
Per Renström, MD, PhD
• Professor emeritus, Karolinska
Institutet, Stockholm, Sweden
• ATP Medical Director,
• Member ITF Medical and
Scientific Commission
• Founder and Past President
Discussion at Ketcher Sport –
FFI/ DIMS Symposium , Odense,
Danmark, October 29, 2010
Rationale for this lecture
Facts

The number of injuries in tennis
is increasing and changing in
character
Something needs to be done!!
• Outstanding medical service,
reliable outcome data and
prevention are getting more
important
Empiri on injuries in tennis
Content
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Tennis is a sport with great demands
Risk factors
The tennis serve
Injury rates in tennis are low.
Types of injuries
Prevention- How?
Well controlled medical service
Take home message
Empiri on injuries in tennis
Tennis is a
demanding sport
Tennis a game for everybody
 Tennis is a global sport, with
participation in more than 200
countries affiliated with the
International Tennis Federation - ITF
 There are 60 million tennis players -both male and female
 Played by all ages --from age 5 to 100
 Tennis is an exciting sport
Tennis is a demanding sport
physically, mentally and emotionally.
Basics
 An elite young player practices >2,3 h per
day 6,1 days per week.
Forces and loads associated with tennis stroke
 Upper trunk rotation 870 deg/s
Fleisig et al , Sports Biomechanics 2:51, 2003
 Shoulder internal rotation velocity 2090 deg/sec
 Elbow extension 1230 deg/sec.
Elliot et al J. Med.Sci.Sports 6:76, 2003
Great demands in tennis
We do know quite a bit about the
inherent demands in tennis, in terms of
 Forces and velocities,
 Ranges of motion, and amount of tennis play
And some about
 The musculoskeletal maladaptations
Van der Hoven, Kibler: Br J Sports
Med, ;40(5):435 2006
But not much about
 The stress of playing the year around
 The true incidence of injuries
Empiri on injuries in tennis
Risk factors
General risk factors in tennis?
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Age
Previous injury
Poor biomechanics especially in the serve
Muscular fatigue
Reduced hamstring to quadriceps
strength ratio?
Reduced range of motion of e.g. the
shoulder and hip?
Inadequate warm-up?
Peak performance?
Other?
Multifactorial model of etiology
Intrinsic risk factors
Age
Previous
injury
Exposure to extrinsic
risk factors
Predisposed
athlete
Athlete
at risk
Inciting
event
INJURY
Flexibility
Strength
Risk factors for injury
Meeuwisse WH: Clin J Sports
Med 4: 166-170, 1994
Injury mechanisms
Empiri on injuries in tennis
The tennis serve
The overhead serve motion
The serve was the predominant stroke accounting for
 45% in French Open and
 60% in Wimbledon of strokes during service games.
Johnsson et al. Br J Sports Med, 187: 901, 2006
 Is unnatural and highly dynamic, often
exceeding the physiological limits of the joint.
 Optimal shoulder function requires good
kinetic chain function, optimal stability, and
coordination of the scapula in the overhead action.
Van der Hoven, Kibler: Br J Sports Med, May;40(5):435, 2006
Kinetic Chain
• Kinetic chain allows generation and
transfer of forces from the leg to the hand
• 50% of total kinetic energy and total
forces of the serve are developed in
the leg, hip, trunk link
• Shoulder has 13% contribution to total energy and
21% contribution to total force
Toyoshima, et al, 1974
Physical maladaptation
of the shoulder
Maladaptation
= adaptation that cause more harm than help
Exists in 60-86% of all tennis players
In the dominant shoulder
• Increased external rotation
• Decreased internal rotation
Maladaption
• Cause biomechanical changes that will
result in injury in shoulder and elbow
Empiri on injuries in tennis
Injury rates in
tennis are low.
A systematic search of
published reports 1966-2005
Base: 39 case reports, 49 laboratory studies, 28 descriptive
epidemiological studies, and 3 analytical studies.
The principal findings of the review were:
1. Great variation in the reported incidence of tennis injuries
2. Most injuries occur in the lower extremities, followed by the
upper extremities and then the trunk
3. Very few longitudinal cohort studies that investigated the
association between risk factors and the occurrence of
tennis injuries (odds ratios, risk ratios, hazard ratios)
4. No randomised controlled trials on injury prevention in
tennis.
Pluim, et al Br. J. Sports Med. 2006;40;415-423
Tennis injuries
Tennis does have a unique profile of injuries.
Pluim, Safran USRSA, 2004.
Injury incidence varied from
 0.05 to 2.9 injuries per player per year
 0.04 -- 3,0 injuries/1000 hours per hour of play
Location
 Most acute injuries occurred in the lower extremities
 Most chronic injuries were located in the upper
extremities.
 Injuries to the trunk comprised 5% to 25% of all injuries
Pluim, et al: Br. J. Sports Med. 2006;40;415-423
Injury severity
 Injuries sustained while playing indoors tended to be
more severe than outdoor injuries, with a higher
percentage requiring medical treatment.
Vriend et al Amsterdam: Consument en Veiligheid, 2005
 3.3% of acute and 2.2% of chronic injuries required
surgery.
Kuhne et al. Sportverletz Sportschaden 2004;18:85–9.
 There was no significant difference in the overall rate of
injury (new and recurrent) between male and female
players.
Injury rates between players
of different ability
• In elite young athletes it was found that
performance success was significantly
related to injury rate.
Baxter-Jones et al. Arch Dis Child 1993;68:130–2.
• No statistical differences in overall injury
incidence and prevalence rates across all skill
levels.
Jayanthi N, Sallay P, Hunker P, et al.
Med Sci Tennis 2005;10:12–15.
The incidence of tennis
injury is elusive
Injury rates in the general tennis population are low
• 1-3 injuries / 1000 hours per play per year
Pluim B. STMS congress, Japan, 2008
Very few reliable figures available!!
Injury types –Most very benign
• Blisters, abrasions, cramps
• Strains e.g. hamstring strain
• Sprains e.g. ankle sprain
• Tendon injuries 3%
35%
26%
Kuhne et al. Sportverletz Sportschaden 2004;18:85–9.
Injury profile in junior players in a local tennis
club - a prospective two year study
Goal: All 12-18 years old members of a tennis club playing
more than twice weekly were asked to participate.
• The injury incidence for boys was 1.7 injuries/1000 hours of
tennis playing time and for girls 0.6.
• Ankle sprains, low back pain, groin pain, overuse injuries of
the lateral elbow and rotator cuff were most common
Conclusions
 The injury incidence in junior tennis is low..
 Almost 50 % of the injuries required absence from tennis
during more than four weeks.
Hjelm N, Werner S, Renstrom P: Knee Surg Sports
Traumatol Arthrosc. 2010 Jun;18(6):845-50
The most common injury
locations in boys and girls
3 (11%)
7 (10%)
6 (22%)
5 (19%)
15 (21%)
9 (12%)
3 (11%)
16 (22%)
3 (11%)
Empiri on injuries in tennis
Type of
injuries
Shoulder Injuries in Tennis
Shoulder disorders account for up to
50% of tennis injuries. They are
 Increasing in number
 Seen in younger ages
 Getting more complex
Most common are
 Labrum tear
 Rotator cuff disorders
Back pain in tennis is not
going away!
Low back pain
 50% of elite players had a history of
low back pain of at least one week
duration
 46,7 % of retired players with
back pain had abnormal
radiographs of the lumbar spine
Swärd et al 1990
Back and trunk pain
and injury
 MRI findings such as facet joint
arthritis and synovial cysts and pars
injuries are common in
asymptomatic young tennis players.
Alyas, Turner et al. Brit J. Sports
Med. 2007. 41: 836-841
What does this really mean?
Lower leg injuries
Knee injuries 19% of all injuries
• Occasional MCL and ACL injury
Muscle strain common
 Rectus abdominis strain –eccentric overload
during cocking in the serve
 Hamstring injury increasingly common.
 ”Tennis leg” -- Gastrocnemius strain
Achilles tendon injury
• 5,5% incidence in players over 40
What really happens when
you sprain your ankle?
Ankle and foot injuries
• Ankle sprains – still most common injury in tennis
• Higher proportion females than males 9,7% vs 4,5%
Iwamoto et al , STMS congress, Tokyo, 2008
• Stress fractures eg. 5th metatarsal
• Plantar fasciitis is common in older players
• Hallux rigidus
• Tennis toe – due to impaction of the toe
onto to the toe box of the shoe
Empiri on injuries in tennis
Prevention
- How?
Injury prevention
“Research on sports injury prevention is scarce”
 The information has typically been obtained from
descriptive projects
However,
• These studies have not been designed
to provide in-depth information on
injury mechanisms and risk factors
•
This information is needed in order
to propose relevant preventive measures.”
Lars Engebretsen, Director of Science, IOC, 2008
Prevention of injuries in sport
-- Some milestones
1982 Jan Ekstrand, Sweden presented his Ph.D.
Thesis on prevention
1992 Willem van Mechelen presented his
”Sequence of prevention”
1996 FIFA F-Marc founded with support for
studies on prevention Dvorak, Junge
2005 First congress of injury prevention in Oslo
Noway by Engebretsen, Bahr
2006 Definition of football injury
2009 Definition tennis injury
”Sequence of prevention”
1. Establishing the
extend of the
injury problem:
-- incidence
-- severity
2. Establishing
etiology and
mechanisms of
sports injuries
4. Assessing its
effectiveness
by repeating
step 1
3. Introducing a
preventive
measure
34
van Mechelen et al. Sports Med 14: 82-99, 1992
International consensus on injury definitions
in team sports has been worked out
Landmark study
Consensus statement on injury definitions and data
collection procedures in studies of football (soccer)
injuries
Fuller CW, Ekstrand J, Junge A, Andersen TE, Bahr R, Dvorak J,
Hägglund M, McCrory P, Meeuwisse WH (2006)
Simultaneous publication in:
• Br J Sports Med 40(3): 193-201
• Clin J Sports Med 16(2): 97-106
• Scand J Med Sci Sports16(2): 83-92
Injury definition in an
individual sport --Tennis
The International Tennis Federation
has now worked out a
• “Consensus statement on
epidemiological studies of
medical conditions in tennis”
This article is due to be published in British
Journal of Sports Medicine, 43, 12, 2009
• Babette M Pluim, Colin W Fuller, Mark E Batt, Lisa
Chase, Brian Hainline, Stuart Miller, Bernard
Montalvan, Per Renström, Kathleen A Stroia, Karl
Weber, Tim O Wood
What must tennis do??
Meticulous injury registration
 is vital to establish the factors associated with
injury in tennis, using the results
 to implement policies and
 strategies to minimise such injuries.
The tennis medical groups (ITF, ATP, WTA )
have now worked for the last 10 years
to produce a system where the players injuries , injury
mechanism, risk factor etc can be registered with the goal
 To follow tennis injuries over time.
 There are now tests going on with the Sutton system.
Injury prevention –
Shorter season
Obervation: We all see tired and worn out
players during the fall tournaments!!!
Sony Ericson WTA Tour has decided
 The female players will take a three weeks
break in the summer after Wimbledon.
ATP World Tour is now
 Looking into shortening the season
 Will most likely take a decision on 8
weeks break in November and December
Empiri on injuries in tennis
Well controlled
medical service
Medical Services Committees
ATP World Tour , Sony Ericson WTA Tour and ITF all
have Medical Services Committes whose primary aim is
 the safety of the players
 maintaining the credibility of the game.
ATP World Tour Medical Services are given by
 Seven full-time Sports Medicine Therapists (SMT’s)
 Three orthopaedic sports medicine specialists
and Todd Ellenbecker, RPT as head constitute
ATP Medical Services committee
Top Level Tennis Medical Service
is excellent and the players are
satisfied
Advantages with the tennis medical service
 The players meet the same medical providers the
whole time and this is a base for success.
 The whole management of ATP World Tour
tennis medical service is well planned from the
locker room to the court management.
The medical service for tennis top players
during the weekly world wide tournements is
one of the best medical service available in sport
“Finally Action to be Taken on
Fake On-Court Injuries”
As seen October 19, 2009 in Bob Larson's
column...
• “Few rules in tennis have been abused
more than the one which allows a player
to demand a medical time in the midst of
a game when he or she insist the onset of
cramp makes it impossible to continue.
• Those who do not mince their words call it
the most common form of cheating in
tennis “
Medical Evaluation and cramping
 During the warm-up or the match, the player may
request the Physiotherapist/Athletic trainer to evaluate
him/her during the next change over or set break.
 Only in the case that a player develops an acute medical
condition that necessitates an immediate stop in play may
the player may have an immediate evaluation
 Medical Time-Out for 3 minutes is given when
additional time for medical treatment is required.
Muscle Cramping:
 A player may receive treatment only during the
time allotted for change of ends and/or set breaks.
 Players may not receive a medical time-out for
muscle cramping.
Empiri on injuries in tennis
Take home
message
In summary
The incidence and the severity of
tennis injury will not decrease!!
We have to realize this!!!!
 Therefore the work on high quality medical care
and prevention must have highest priority!!
 There is no short cut!!!!
 I really like the mantra of the Swedish
writer P-O Enquists mantra:
”I have always been an opponent to
high jump without a bar!”
Take home message
 Tennis is a demanding sport physically, mentally and
emotionally.
 Maladaptations are found in 60-86% of tennis players
 The adaptive response to the physical demands in
tennis is started to be understood
 The incidence of tennis injury is low but
tend to be more frequent and severe
 Shoulder injuries are an increasing problem
 They tend to start occurring at an earlier age
than before
Take home message
 Some mechanical problems may be addressed by
detailed coaching analysis and training
 The most important prevention strategy is
to offer superior medical service
 The management of ATP, WTA and ITF tennis
medical service is today well planned from the
locker room to the court management.
 Although tennis players get excellent medical
care-- injuries do not decrease
We need really need to update the management
continuously and focus on prevention!
If we can give the players good
service we can enjoy the
strawberries at Wimbledon
At every Wimbledon the
visitors consume
 28.000 kilos of strawberries
 7.000 litres of dairy cream
along with
 150.000 glasses of PIMM´s and
 17.000 bottles of champagne
It is such a great pleasure to be
invited to give this lecture
Thanks for your attention !!