This study examined whether gate setup and turn radii influence energy dissipation in slalom skiing. 3D kinematical measurements were performed over two runs on the same slope in a WC slalom competition with two different gate setups: 1) open gates (OG) and 2) open gates with a delayed gate (DG). Using the arithmetic mean of the skis’ turn radii (R AMS) the slalom turns were divided into 1) initiation phase (R AMS > 15m) and steering phase (R AMS < 15m). The results show differences between OG and DG regarding: 1) the absolute center of gravity’s (CG) velocity, 2) absolute acceleration, 3) CG turn radii and R AMS, 4) ground reaction forces (F) and 5) energy dissipation during skiing (all p < .05). In both gate setups the highest F and the highest energy dissipation were present in the steering phase, whereas the correlation between R AMS and energy dissipation was low (OG: r = .364 and DG: r = .214, both p < .001). In summary, compared with plain open gates, an additional delayed gate prolonged the turn radii and decreased energy dissipation in the beginning of the initiation phase, despite the fact that the relative frequency of occurrence of the highest energy dissipation was higher in DG.
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How Gate Setup and Turn Radii Influence Energy Dissipation in Slalom Ski Racing
Matej Supej and Hans-Christer Holmberg
Errors in Measuring Glenohumeral Arthrokinematics With 2-Dimensional Fluoroscopy
Meena Makhija, Jasobanta Sethi, Chitra Kataria, Harpreet Singh, Paula M. Ludewig, and Vandana Phadke
. This study does not report any experimental data for assessing magnification errors, 3D kinematic measurements, or videofluoroscopy. Subject movement between trials cannot be neglected when testing projection errors. However, this was minimized by moving the fluoroscopy unit. The same image was
Knee Frontal Plane Projection Angle: A Comparison Study Between Drop Vertical Jump and Step-Down Tests With Young Volleyball Athletes
Gabriel Andrade Paz, Marianna de Freitas Maia, Haroldo Gualter Santana, Humberto Miranda, Vicente Lima, and John D. Willson
consistently identify peak FPPA values during the DVJ task and may not be appropriate for the fast movement for accurate assessment. It is important to also consider that the FPPA, at best, reflects 23% to 30% of the variance of 3D kinematic measurements during the activities including unilateral and bilateral
Are Action Sport Cameras Accurate Enough for 3D Motion Analysis? A Comparison With a Commercial Motion Capture System
Gustavo Ramos Dalla Bernardina, Tony Monnet, Heber Teixeira Pinto, Ricardo Machado Leite de Barros, Pietro Cerveri, and Amanda Piaia Silvatti
video cameras: accuracy analysis and trajectory reconstruction . Comput Methods Biomech Biomed Engin . 2013 ; 16 ( 11 ): 1240 – 1248 . PubMed ID: 22435960 doi:10.1080/10255842.2012.664637 22435960 10.1080/10255842.2012.664637 9. Dutta T . Evaluation of the Kinect™ sensor for 3-D kinematic
Trunk–Pelvis Kinematics Variability During Gait and Its Association With Trunk Muscle Endurance in Patients With Chronic Low Back Pain
Rasool Bagheri, Ismail Ebrahimi Takamjani, Mohammad R. Pourahmadi, Elham Jannati, Sayyed H. Fazeli, Rozita Hedayati, and Mahmood Akbari
Kinematic Data Analysis A 3D kinematic measurement was employed to verify the displacement and variability of trunk segments in 3 planes of movement relative to the pelvic segment. The angles were calculated in the following order: (1) sagittal, (2) frontal, and (3) transverse. The variability of angular
