european college of sport science

Thursday, June 25th, 2009
dPT values from passive extension (resting state) lead to overestimated PT force by ~383 N (15%) and ~521 N (15%), during maximum
concentric and eccentric knee extensions respectively.
The erroneous PT force values would overestimate stress of the PT and can lead to erroneous conclusions regarding the risk of tendon
injury during daily living activities. These findings also indicate that significant errors may have been made by previous studies in estimations
of PT force and stress using resting dPT measurements.
References
Tsaopoulos et al. (2007). J. Biomech. 40, 15, 3325-32.
CADAVERIC VERSUS ULTRASONOGRAPHIC ASSESSMENT OF THE LONG HEAD OF BICEPS FEMORIS AND SEMINTEND-
INOUS MUSCLE ARCHITECTURE
KELLIS, E.
ARISTOTLE UNIVERSITY OF THESSALONIKI
The purpose of this study was to document and compare the architectural parameters (fascicle length, angle of pennation, muscle thickness,
tendon length) of the long head of biceps femoris (BFlh) and semitendinosus (ST) muscles measured from direct dissection as opposed
to those measured using ultrasound (US). The BFlh and ST were examined bilaterally in 6 legs from 3 male cadavers (mean age
72±6, range 65±83 y). Data were obtained from direct measurement and ultrasonographic scans of cadaveric specimens. With the
cadavers in the prone position, US scans were taken from proximal, mid-belly and distal positions of each muscle. From the recorded US
images, the fascicle length, pennation angle and muscle thickness were measured. Following US imaging, the muscles were isolated
and dissected from proximal to distal location in the direction of muscle fibers. Subsequently, the pennation angle and muscle thickness
were measured. Bundles of fascicles were isolated and their length was measured. Two-way analysis of variance designs were used to
compare fascicle length, angle of pennation and muscle thickness at matched locations in both groups. The results showed that the BF
had a fascicle length of 7.50 ± 1.98 cm to 8.60 ± 2.31cm, a pennation angle ranging from 12.34 ± 2.76° to 15.03 ± 3.32° and a muscle
thickness of 2.41 ± 0.41 cm to 3.58 ± 0.76 cm. The ANOVA results indicated that there were non-significant differences between US and
direct measurement in all measured variables (p > 0.05). The results showed that the ST had a fascicle length of 17.23 ± 3.11cm to 21.58 ±
3.25 cm, a pennation angle ranging from 12.16 ± 2.98° to 14.96 ± 3.34° and a muscle thickness of 1.21 ± 0.40 cm to 2.66 ± 0.62 cm. The
ANOVA results indicated that there were non-significant differences between US and direct measurement in all measured variables (p >
0.05). Compared with cadaveric measurements, the US variables displayed an error which is less than 5% for length measures and 3-5%
for pennation angles. Pearson correlation coefficients showed a high agreement (r >0.90) between the two techniques. The present
results showed that determination of muscle architecture in BF and ST muscles using ultrasound is a valid technique, despite the complicated
architecture of these muscles. The application of US for modeling human hamstring muscle at least under resting conditions is
guaranteed.
FEMALES RUN DIFFERENT THAN MALES - IMPLICATION FOR RUNNING INJURIES?
GEHRING, D., MORNIEUX, G., FLEISCHMANN, J., GOLLHOFER, A.
UNIVERSITY OF FREIBURG
Introduction: Epidemiological studies suggest that specific running injuries occur with a higher frequency in females. Women have shown
to be more prevalent to the most common running injury, the patella femoral pain syndrome (Taunton et al., 2002). As previous results
suggest, that knee joint loading is deemed to be a risk factor for specific running injuries like the patella femoral pain syndrome (Stefanyshyn
et al., 2006), the aim of the present study was to determine gender differences in knee joint biomechanics in experienced runners.
Methods: 3D-kinematics (Vicon) and kinetics of the knee joint were measured in 15 male and 15 female experienced runners at a running
speed of 4m/s. Simultaneously, the activation of quadriceps and hamstrings muscles were determined by the use of telemetric electromyography.
Results: Females flexed their knees 5° less than males. While the males exhibited a clear knee joint adduction during the complete stance
phase with peak values of 7° in average, the females showed a neutral or even abducted knee joint alignment with a peak abduction of
3° (p < 0.001). The maximal knee joint adduction moments were comparable between genders. However, the females had a significantly
higher knee joint adduction loading (p < 0.01) during the braking phase, which was mainly caused by the multiple higher medial ground
reaction forces than in males. Compared to males, the females’ quadriceps activation was pre-shifted (about 15ms) and peaked in the
braking phase.
Discussion: In accordance with previous studies females demonstrated a significant greater knee joint abduction (Ferber et al., 2003)
which was combined with increased adduction moments in the initial braking phase. As frontal plane loading is associated with specific
running injuries like the patella femoral pain syndrome (Stefanyshyn et al., 2006), the results of the present study may help to explain why
females are more prone to this kind of injury. Furthermore, the pre-shifted quadriceps activation, related to the reduced knee flexion and
therefore stiffer knee joint configuration in females, indicates that gender differences in knee joint control are even present in the sagittal
plane.
References
Taunton JE, Ryan MB, Clement DB, McKenzie DC, Lloyd-Smith DR, Zumbo BD. (2002). Brit. J. Sports Med., 36, 95-101.
Stefanyshyn DJ, Stergiou P, Lun VMJ, Meeuwisse WH, Worobets JT. (2006). Am. J. Sports Med., 34, 1844-1851.
Ferber R, McClay Davis I, Williams DS. (2003). Clin. Biomech., 18, 350-357.
RELATIONSHIP OF REARFOOT ANGULAR VELOCITY TO VERTICAL AND LEG STIFFNESS IN RUNNING
ERIKSRUD, O., ELTARVÅG, B., SMITH, G.
NORWEGIAN SCHOOL OF SPORT SCIENCES
The mass-spring model is used to describe the mechanical behavior of the lower extremity during running. At the middle of stance the
spring is maximally compressed which is associated with maximal pronation, commonly described by rearfoot eversion. Few have
looked at the relationship between foot motion and position to leg stiffness (Viale 1998), but not angular velocity. The current study which
focuses on angular velocity was part of a larger project evaluating the influence of lower extremity joint kinematics on leg and vertical
stiffness.
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