european college of sport science

Thursday, June 25th, 2009
15:15 - 16:45
Oral presentations
OP-RE01 Rehabilitation 1
DIFFERENCES IN STRENGTH AND JUMPING TECHNIQUE BETWEEN ACL-RECONSTRUCTED AND NON-INJURED HAND-
BALL PLAYERS
KRISTIANSLUND, E., MYKLEBUST, G., SHIMA, Y., BAHR, R., KROSSHAUG, T.
NORWEGIAN SCHOOL OF SPORT SCIENCES
Introduction: About one third of ACL-injured elite handball players are unable to return to their pre-injury sport participation level. It is still
unclear to what degree the ACL-reconstructed athletes returning to sports regain symmetrical landing patterns and thigh strength after
rehabilitation. Altered motion patterns and side-to-side differences may predispose players to new ACL injuries. Based on this we investigated
differences in strength and knee motion between legs in ACL-reconstructed handball players and differences in knee motion
between ACL-reconstructed and non-injured handball players.
Material and Methods: All players in the Norwegian female elite handball series were invited for testing and 184 players (about 85%)
were tested. Of these, 20 players had an unilateral ACL reconstruction (mean time since injury 3.5±2 (SD) yrs, 8 patellar and 12 hamstrings
grafts). These were matched with twenty uninjured players (age 24.5±4.6 vs. 24.3±4.3 years, height 176.2±6.9 vs. 175.8±6.0 cm).
All test subjects were fit for match play on the day of testing. The players completed maximal isokinetic quadriceps and hamstrings
strength testing at 60 º/s. An eight-camera motion analysis system captured the motion of three maximal 30 cm vertical drop jumps at
240 Hz. Key kinematic and kinetic values were calculated and the average of three jumps was used for all analyses.
The ACL-reconstructed leg of injured players was compared with the uninjured leg using paired t-tests. The averages of both legs were
compared between groups using independent t-tests.
Results: When comparing legs of previously injured players, the ACL-reconstructed leg had lower quadriceps (170.2±6.5 (SEM) Nm vs
181.6±5.8 Nm, p=0.046) and hamstrings (100.6±5.8 Nm vs 108.6±4.8 Nm, p=0.012) strength. For the drop jumps no differences were
found between legs for maximal knee joint moments or maximal knee joint moments during the first 50 ms.
Significant differences in knee flexion at initial contact were found between the groups of players. The ACL-reconstructed group landed
with less knee flexion compared to the non-injured group (29.6º±1.4º vs 34.6º±1.4º, p=0.015), but there was no difference in valgus
angles at initial contact. ACL-reconstructed and non-injured players displayed similar values of maximum knee flexion and knee valgus
as well as maximum knee flexion moment (211±8 vs 204±11 Nm, p=0.605) and valgus moment (38±6 vs 40±5 Nm, p=0.779) during
landing phase.
Conclusion
ACL-reconstructed players display significant strength differences between legs, with the reconstructed leg being weaker than the uninjured
leg. This suggests that rehabilitation before return to sport may be inadequate. Despite the strength imbalances, the injured players
display symmetrical motion patterns an land similar to non-injured players, with an exception of knee flexion at landing. This may protect
against new injuries, although differences in joint loading patterns may be revealed with more demanding tasks.
MEDICAL INFRARED THERMOGRAPHY AS A SCREENING TOOL FOR KNEE INJURIES IN PROFESSIONAL JUNIOR ALPINE-
SKI-RACERS IN AUSTRIA – FINDINGS OF A PILOT STUDY
HILDEBRANDT, C.
UNIVERSITY OF INNSBRUCK
INTRODUCTION: Medical Infrared Thermography (IFT) is a non-radiating and non-invasive analysis tool for physiological functions related
to skin-temperature control. In the past it has been successfully used in veterinary medicine for injury prevention and management in
race horses (TURNER et al. 2000). Any significant asymmetry of more than one degree centigrade from two sides of the body may indicate
a pathophysiological process. Knowing that similar anatomical and physiological conditions exist, it can be assumed that IFT is a
helpful to manage injuries
in human athletes. But there is a lack of evidence, demonstrating the successful use with the advantage of twenty first century technology
(DIAKIDES 2008).
The knee is a weak link and the frequently affected in alpine skiing (PUJOL et al 2007). Long-term consequences such as osteoarthritis
and high treatment costs raise safety concerns.
Valid and reliable measurements are crucial to evaluate IFT as a screening tool in the prevention, diagnosis and rehabilitation of knee
injuries in athletes. For this purpose the standardisation methods, proper recordings and the optimal image analysis were defined.
METHODS: We conducted a pre-season measurement of 35 female and 52 male junior alpine ski racers (non-injured, previous injury and
acute injury) aged 14-19 years from the “Skigymnasium Stams”. After an acclimatisation period of 20 minute we recorded an image of the
anterior/posterior and medial/lateral aspect of both knees with an infrared camera (TVS500EX). To analyse the images we used the
software GORATEC Thermography
Studio Report. A physiotherapist examined the functional aspect of the knee.
RESULTS: In 6 male athletes intra-individual thermal asymmetries of 1.4 (±0.58) degree Celsius over the tibia revealed overuse reactions
such as Osgood-Schlatter disease. The clinical examinations confirmed these findings. The evaluation of 7 feminine and 1 male athlete
with an operation of the knee over the last 6 months clearly demonstrated the localisation and extent of the affected area.
DISCUSSION: This study was instrumental in learning how to use the technology. It clarified the potential of IFT for a more objective and
uncomplicated evaluation of knee injuries. Pre-season measurement will be compared with post-season measurements to evaluate the
physical stress.
In case of thermal asymmetries of more than one degree Celsius they will be analysed with structural measurements such as magnetic
resonance imaging and X-ray. These results can be used to adjust the training programs of the at-risk athletes and may lessen the
severity and frequency of overuse and acute knee injuries.
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