Search results for "Biomechanical"
showing 10 items of 524 documents
Analysis of elite swimmers' activity during an instrumented protocol
2009
The aim of this study was to examine swimmers' activity-technical device coupling during an experimental protocol (MADsystem). The study was conducted within a course-of-action theoretical and methodological framework. Two types of data were collected: (a) video recordings and (b) verbalizations during post-protocol interviews. The data were processed in two steps: (a) reconstruction of each swimmer's course of action and (b) comparison of the courses of action. Analysis from the actors' point of view allowed a description of swimmer-technical device coupling. The results showed that the technical device modified the athletes' range of perceptions and repertoire of actions. They also indica…
New intramedullary locking nail for olecranon fracture fixation--an in vitro biomechanical comparison with tension band wiring.
2010
The aim of this study was to determine the difference in displacement of a newly designed intramedullary olecranon fracture fixation device compared with multifilament tension band wiring after 4 cycles and 300 cycles of dynamic continuous loading.In eight pairs of fresh-frozen cadaver ulnae, oblique olecranon fractures were created and stabilized using either newly designed intramedullary olecranon nail or multifilament tension band wiring. The specimens were then subjected to continuous dynamic loading (from 25 N to 200 N) using matched pairs of cadaveric upper extremities. The Wilcoxon test was used to determine statistical differences of the displacement in the fracture gap.After 4 cycl…
Volar Fixed-Angle Plating of Distal Radius Fractures
2011
The purpose of this biomechanical study was to determine whether a multidirectional fixed-angle plate with locking screws or with locking pegs in the distal fragment would optimize fixation of Orthopaedic Trauma Association (OTA) type A3 distal radius fractures.Eight pairs of fresh-frozen human distal radii were used. Extra-articular distal radius fractures were created and stabilized with a multidirectional volar fixed-angle plate. The radii were randomized into 2 matched-paired groups. The distal fragment in Group I was stabilized with 7 locking screws. The distal fragment in Group II was fixed with 7 locking pegs. The proximal fragment in both groups was fixed with 3 screws. The specimen…
Periosteal repair of the dorsal calcaneocuboid ligament: a comparative biomechanical study.
2007
Background: Isolated lateral calcaneocuboid joint instability rarely is described. Missed or delayed diagnosis resulting in inadequate treatment may lead to chronic instability, followed by sports inability and handicap in daily life. Besides arthrodesis, anatomic repair augmenting the elongated dorsal calcaneocuboid ligament with a local periosteal flap has recently been described for treatment. Methods: In a controlled laboratory study, eight isolated fresh-frozen human cadaver calcaneocuboid specimens were strained in a varus direction until failure of the dorsal calcaneocuboid ligaments. Then the dorsal calcaneocuboid ligaments were reconstructed with free periosteal flaps and tensile …
Effect of skiing speed on ski and pole forces in cross-country skiing.
2008
Purpose: The present study characterized pole and ski forces in classical technique cross-country skiing. Eight elite junior cross-country skiers performed diagonal skiing at 65%, 75%, 90%, and 100% of maximum speed on a stable 100-m-low uphill (2.5[degrees]). Method: The ski and the pole forces (vertical (Fz) and horizontal (Fy) directions) on the right and left sides were recorded separately when the skier skied over a special custom-made force platform system placed at the end of the uphill course. The entire system consisted of four separate 20-m-long rows of 1-m-long force plates connected in series, row by row. Results: When the forces were averaged for the various functional phases o…
Sprint mechanical variables in elite athletes: Are force-velocity profiles sport specific or individual?
2019
Purpose The main aim of this investigation was to quantify differences in sprint mechanical variables across sports and within each sport. Secondary aims were to quantify sex differences and relationships among the variables. Methods In this cross-sectional study of elite athletes, 235 women (23 ± 5 y and 65 ± 7 kg) and 431 men (23 ± 4 y and 80 ± 12 kg) from 23 different sports (including 128 medalists from World Championships and/or Olympic Games) were tested in a 40-m sprint at the Norwegian Olympic Training Center between 1995 and 2018. These were pre-existing data from quarterly or semi-annual testing that the athletes performed for training purposes. Anthropometric and speed-time sprin…
Dynamic biomechanical analysis of different olecranon fracture fixation devices--tension band wiring versus two intramedullary nail systems: an in-vi…
2007
Abstract Background. The aim of this study was to develop a test-setup with continuous angle alteration to imitate joint motion for the evaluation of 3 different olecranon fracture fixation devices. Methods. Twenty-one fresh cadaver upper extremities underwent olecranon fracture by the means of transverse osteotomy and received 3 different fixation systems. Group 1: Tension band wiring according to Weber. Group 2: XS-nail with 9 holes, all locked with 2 mm threaded K-wires. Group 3: Olecranon Nailing System with 90 mm length, locked with 2.7 mm screws, a variable angle locking hole for the proximal fragment and a proximal locking end cap. The servo-pneumatical test stand worked with a rotat…
The Relation between Geometry and Time in Mental Actions
2012
Mental imagery is a cognitive tool that helps humans take decisions by simulating past and future events. The hypothesis has been advanced that there is a functional equivalence between actual and mental movements. Yet, we do not know whether there are any limitations to its validity even in terms of some fundamental features of actual movements, such as the relationship between space and time. Although it is impossible to directly measure the spatiotemporal features of mental actions, an indirect investigation can be conducted by taking advantage of the constraints existing in planar drawing movements and described by the two-thirds power law (2/3PL). This kinematic law describes one of th…
Drilling dimension effects in early stages of osseointegration and implant stability in a canine model
2015
Background: This study histologically evaluated two implant designs: a classic thread design versus another specifically designed for healing chamber formation placed with two drilling protocols. Material and Methods: Forty dental implants (4.1 mm diameter) with two different macrogeometries were inserted in the tibia of 10 Beagle dogs, and maximum insertion torque was recorded. Drilling techniques were: until 3.75 mm (regular-group); and until 4.0 mm diameter (overdrilling-group) for both implant designs. At 2 and 4 weeks, samples were retrieved and processed for histomorphometric analysis. For torque and BIC (bone-to-implant contact) and BAFO (bone area fraction occupied), a general-linea…
Kinematics of obstacle clearance in the rat
2010
Although the rat has become the favourite animal model in preclinical research on locomotion, studies designed to assess the strategy used by rats to avoid obstacle are lacking. Using an optoelectronic 3D motion analysis system, we therefore, compared the step pattern, timing and length variables of locomotor cycles, trajectories and joint angles of limbs when rats step between and over obstacles (3 cm-high) fixed on a treadmill belt (25 cm/s). Motion in all four limbs of adult animals with an initial age of 11 weeks was serially recorded for a period of 10 weeks. The results showed that obstacle clearance is associated with the reorganization of the basic step pattern resulting in increase…