Prevention of knee injuries in ski racing
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Fakultät für Sport- und Gesundheitswissenschaft Technische Universität München
Prevention of knee injuries in ski racing
Peter Spitzenpfeil, Andreas Huber *, Karlheinz Waibel **
Faculty of Sport Science, Technische Universität München, Germany
* Olympiastützpunkt Bayern, Munich, Germany
** German Ski Team, Munich, Germany
injury severity No time
Problem >28 days
loss
19%
31%
1–3 days
8%
injury type 8–28 days
27%
4–7 days
15%
nervous other
system/concus
sion
3% injured part
7%
skin/laceration head 8.5% shoulder 6.9%
4%
fractures/bone upper arm 0.5%
stress
19% ellbow 1.6%
contusion
12% chest 2.1%
hand/wrist 10.6%
muscle/tendon lower back 11%
11%
joint/ligament
44% hip 2.1%
thigh 2.1%
knee 36%
source all data: Flørenes et al., SJMSS, 2010 lower leg 11.1% foot 1.6%
Peter Spitzenpfeil Prevention of knee injuries
external Potential Causes internal
predisposition
slope preparation strength
course setting
endurance
equipment motor control
system ski-boot-binding
Peter Spitzenpfeil Prevention of knee injuries
Injury prevention research –
four step sequence
(mod. van Mechelen 1992, Sports Med)
Step 1
Establishing the
extent of the injury
problem
Step 4 Step 2
Assessing its Establishing the
effectiveness by etiology and
repeating step 1 mechanisms
Step 3
Introducing a
preventive
measure
Peter Spitzenpfeil Prevention of knee injuries
CRIPS – Crash Recognition & Injury
Prevention in Skiing
• Concept
– Development of a sensor-based system to
– Recognize crashes (and/or extraordinary strain) in an early
stage and
– Implement and evaluate preventive measures
• Partners
– TU München (Sport Science, Mechanical Engineering)
– Olympiastützpunkt Bayern
– German Ski Team
– 2D-Systems
– Sportkreativwerkstatt
– Ortema, Junior & Tacke
Peter Spitzenpfeil Prevention of knee injuries
CRIPS – Crash Recognition & Injury
Prevention in Skiing - modules
Crash Recognition
by recording driving conditions
potential parameters:
- physiological (?)
- physical (acc, gyro, force, speed, etc.) A. Huber
general individual
measures measures
Crash Prevention Injury prevention
- course setting - releasing ski reducing fractures V. Senner
- slope preparation - using intelligent braces reducing
- aerodynamic A. Huber joint/ligament injuries
- friction - using “airbags” reducing contusions
reducing loads reducing loads
Peter Spitzenpfeil Prevention of knee injuries
Study: Knee braces as a preventive measure
in alpine skiracing
• Methods:
– literature review
• mechanical functionality: 26 studies
• epidemiologic studies: 14 studies
• performance studies: 8
– performance and compliance test in skiing
• N=3 skiracer
• SL, 9 runs, 5 runs with brace, 4 without
• parameters: time, subjective assessment (questionnaire)
– test of a special designed brace in lab
• common knee brace vs. special designed brace
• knee brace test facility (TU Berlin)
• translation, rotation, varus-valgus stability
Peter Spitzenpfeil Prevention of knee injuries
Study: Knee braces as a preventive measure
Results – literature review – mechanical functionality
method effect
Study/Year subject brace type tibia- rotation varus/valgus
cadaver (C) preventive (P) translation
modell (M) functional (F)
in vivo (I) rehabilitative (R)
Anderson 1992 C F ++ ++
Baker 1987 C F/P +/0
Beck 1986 I F +
Beynon 1999 I F 0
Beynnon 2003 I F ++
Cawley 1989 M R ++ ++
Colville 1986 I F + + 0
Erickson 1992 M P 0
France 1987 M P +
Mathewson 2003 M P ++
Paulos 1987 C F 0
Paulos 1991 M P +
Rupp 1994 M F ++ + ++
Rupp 1994 I F ++ 0
Wojtys 1987 C F + +
Wojtys 1990 C F + ++
Wojtys 1996 I F ++
++ significant effect; + positive effect; 0 no effect;
Peter Spitzenpfeil Prevention of knee injuries
Study: Knee braces as a preventive measure
Results – literature review – epidemiology
Preventive use
• American football
– Hansen 1985, Sitler 1990 reduction of risc factors
– Hewson 1986, Taft 1985 no effects
– Grace 1988, Rovere 1987, Teitz 1987 increase of risc factors
• Eishockey
– Tegner 1991 no effects
Scientific quality quite low, rather old
Rehabilitative use
• Risberg 1999, McDevid 2004 no sig. differencies
• Branch 1989, Ostering 1993, Nemeth 1997 (skiing)
reduction of muscle activity
• Colville 1986, McDevid 2004, Rebel 2001, Risberg 1999, Ulrich 2000
subj. feeling of security
American Academy of orthopedic surgeons: no general need, only in
certain cases
Peter Spitzenpfeil Prevention of knee injuries
Study: Knee braces as a preventive measure Results – literature review – skiing Rehabilitative use Sterett 2006 positive effects Tellatin 2005 (ICSS 2004), Haaker 2006 positive effects, supporting aggressive rehab Bambach 2008, Steadman 1995 positive effects Results – literature review – sensimotor effects Beynnon 1999, Birmingham 2008, Wu 2001 positive effect Jerosch 1995, Perlau 1995 inconsistent effects Branch 1989, Nemeth 1997, Rebel 2001 better knee stabilization Peter Spitzenpfeil Prevention of knee injuries
Study: Knee braces as a preventive measure
Results – literature review – performance
Author Test Usage Differences
Zetterlund 1986 treadmill rehab no diff.
Highgenboten treadmill preventive no diff
1991
Najibi 2005, treadmill rehab reduced
Styf 1992 bloodflow
Veldhuizen 1991 strength, speed, rehab no diff.
and 1994 treadmill
Vailas 1989 strength rehab/preventive no diff.
Sforzo 1989 strength preventive no diff.
Results literature:
-inconsistent findings (many methodological problems)
-preventive effects even possible
-sensimotor effects not negative
-performance not influenced
Peter Spitzenpfeil Prevention of knee injuriesStudy: Knee braces as a preventive measure
Results: Performance and Compliance in skiing
22,5
with knee brace without knee brace with knee brace without
22,06
22
21,49
21,5
21,22 21,24 21,22
21,35 21,04 21,02
20,95 21,22
21 20,84
time [s]
21,03 20,99 20,82
20,79 20,78
20,5 20,37
20,56 20,53
• subjective negative influence on agility and speed of movement
20,49
20,34
20,22 20,22
• subjective
20
feeling that a injuryK.might
B.
be prevented
B. S. A. R.
• negative
19,5
influence of the hard material at fixing points
development of fixing points
19
Run1 Run2 Run3 Run4 Run5 Run6 Run7 Run8 Run9
K. B. 22,06 21,49 21,04 20,95 21,02 20,84 21,22 21,24 21,22
B. S. 21,35 20,79 20,99 DNF 20,78 20,37 20,56 20,53 21,22
A. R. 21,03 DNF DNF 20,49 20,82 20,22 DNF 20,22 20,34
Peter Spitzenpfeil Prevention of knee injuriesStudy: Knee braces as a preventive measure
Development of a special designed brace
common knee brace new design
changing
fixing points
Peter Spitzenpfeil Prevention of knee injuriesStudy: Knee braces as a preventive measure
Method: test of a special designed brace in lab
load direction parameters and values
flexion: 20°
translation path: 30mm
force: up to 300N
translation veocity: 2mm/s
fixation: “best case” – “real case”
translation
flexion: 0°
rotation: +- 25°
moments: up to 36 Nm
rotation velocity: 1,5°/s
fixation: “best case” – “real case”
rotation
flexion: 0°
bending angle: +- 9°
moments: up to 36 Nm
bending velocity: 1,5°/s
fixation: “best case” – “real case”
varus/valgus
Peter Spitzenpfeil Prevention of knee injuriesStudy: Knee braces as a preventive measure
Results: test of a special designed brace in lab
moment at 20° inward rotation moment at 20° outward rotation
force at 20 mm translation fwd force at 20 mm translation rev
moment at 6° varus moment at 6° valgus
Peter Spitzenpfeil Prevention of knee injuriesConclusions • The present injury situation needs to initiate measures at different areas (recognition – load reduction –injury prevention) • Even the findings in literature are inconsistent, knee braces seem to have high potential to prevent at least some injuries in skiing • The influence on performance seems to be negligible • To be accepted among racers, special designs and materials have to be developed • A sensor-based control mechanism may contribute to increased efficiency • We need more information about the race situation Peter Spitzenpfeil Prevention of knee injuries
R&D Targets
Leg fixation
Improve the body/device-interface on upper
and lower leg
Assuring fixation and allowing muscle
movement/activity at the same time
Knee angle kinematic
Improve guide function
Precisely define intended and unintended
knee movement by means of an improved
joint solution
Protective function
Improve control mechanism
Develop sensor-based solutions by using
information from the recognition system
Peter Spitzenpfeil Prevention of knee injuriesWe are working on it …
Thank you very much for your attention!
… this is not our aim!
Special thanks to: Hartmut Semsch, Volker Junior, Christian Hennecke,
Eckehard Fozzy Moritz, Ingo Valtingoir, Veit Senner, Dirk Debus, Thomas
Thimm, Peter Brucker, Hermann Mair, Stephan Legath, Max Rauffer,
Florian Eckert
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