Search Results

You are looking at 41 - 50 of 950 items for :

  • "lower limbs" x
Clear All
Restricted access

Jake A. Melaro, Ramzi M. Majaj, Douglas W. Powell, Paul DeVita and Max R. Paquette

Aging is typically associated with a decrease in skeletal muscle quality including reduced muscle mass, strength and power, and altered muscle fiber and motor unit characteristics. 1 – 5 These altered physiological characteristics contribute to age-related declines in lower limb muscle and nervous

Restricted access

Melanie B. Lott and Gan Xu

coordinated during the turn’s execution. Analyses of kinematics and dynamics at the ankle, knee, and hip joints during step and spin turns have revealed distinct substrategies within the 2 turn types 4 ; however, a large focus of studies concerns the interaction between the lower limb(s) and the ground during

Restricted access

Talita Molinari, Tainara Steffens, Cristian Roncada, Rodrigo Rodrigues and Caroline P. Dias

CT on the muscular strength of older adults’ lower limbs. Material and Methods Search Procedures This systematic review followed the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of works related to the effects of eccentric training on the muscular strength

Restricted access

Felipe García-Pinillos, Carlos Lago-Fuentes, Pedro A. Latorre-Román, Antonio Pantoja-Vallejo and Rodrigo Ramirez-Campillo

structures assessed. Whereas the current work evaluated arch stiffness, defined as the change in AHI due to the increase in load between sitting and standing conditions, Spurrs et al 6 obtained musculotendinous stiffness of the lower limb through the oscillation technique by performing an isometric

Restricted access

Adam Beard, John Ashby, Ryan Chambers, Franck Brocherie and Grégoire P. Millet

-related parameters in world-level rugby union players during a preparation phase preceding an international competition. The main findings were that 4 RSH sessions over a 2-week shock microcycle preparation period resulted in greater improvements (ie, higher lower-limb repeated power output) than similar training in

Restricted access

Jean-Thomas Aubert and Christian Ribreau

Blood flows toward the heart through collapsible vessels, the veins. The equations of flow in collapsible tubes in motion show a strong dependence on body forces resulting from gravity and acceleration. This paper analyzes the contribution of body forces to venous blood flow during walking on level ground. It combines the biomechanics of gait and theory of collapsible tubes to point out that body forces due to gravity and limb acceleration cannot be overlooked when considering the determinants of venous blood flow during locomotion. The study involved the development of a kinematic model of the limb as a multi-pendulum arrangement in which the limb segments undergo angular displacements. Angular velocities and accelerations were determined and the body forces were calculated during various phases of the gait cycle. A vascular model of the leg's major venous system was also constructed, and the accelerations due to body and gravity forces were calculated in specific venous segments, using the data from the kinematic model. The results showed there were large, fast variations in the axial component (Gx–Mx) of the body forces in veins between the hip and the ankle. Acceleration peaks down to –2G were obtained at normal locomotion. At fast locomotion, a distal vein in the shank displayed values of (Gx–Mx)/G equal to –3.2. Given the down-to-up orientation of the x-axis, the axial component Mx was usually positive in the axial veins, and Mx could shift from positive to negative during the gait cycle in the popliteal vein and the dorsal venous arch.

Restricted access

Alan Barr and David Hawkins

An anatomical database was constructed containing three-dimensional geometric representations of the structures comprising the lower extremity. The database was constructed by digitizing 100 high-resolution digital photographic images supplied from the National Library of Medicine’s Visual Human Male (VHM) project. These images were taken of sequential transverse cross-sectional slices of the leg. Slices were located 1 cm apart between a location approximately 3 mm below the superior aspect of the ilium and approximately 2 mm below the distal end of the fibula. Image Tool Software (v. 2.0) was used to manually digitize the perimeters of muscles, tendons, and bones of the pelvis, thigh, and shank from the right leg of the VHM. Additionally, the perimeter of the leg and the inner aspect of the superficial fat layer were digitized. The pelvis was digitized as a hemi-pelvis. Tissue perimeters were characterized using between 10 and 151 nodes within each slice; the number of nodes varied depending on the tissue’s size. Transverse cross-sectional slice number, structure identification, node number, and the two-dimensional coordinates of each node were stored in a data file. The information contained in this file is unique and provides a database that researchers can use to investigate questions related to tissue anatomy and movement mechanics that cannot be considered using existing musculoskeletal data sets.

Restricted access

Gunnar Andréasson and Lars Peterson

The dynamical behavior of sport shoes and surfaces has been measured and combined with a clinical study of injuries. The method used for the technical measurement has been the DIN Standard, and the clinical injury assessment has been obtained from several teams using different shoes and surfaces. The results point out that a dynamical spring constant can be used as a means of predicting potential athletic injuries. For the interaction between a shoe and surface the combined dynamical modulus may not exceed 3.2 MPa.

Restricted access

Mansour Eslami, Mohsen Damavandi and Reed Ferber

There is evidence to suggest that navicular drop measures are associated with specific lower-extremity gait biomechanical parameters. The aim of this study was to examine the relationship between navicular drop and a) rearfoot eversion excursion, b) tibial internal rotation excursion, c) peak ankle inversion moment, and d) peak knee adduction moment during the stance phase of running. Sixteen able-bodied men having an average age of 28.1 (SD = 5.30) years, weight of 81.5 (SD = 10.40) kg, height of 179.1 (SD = 5.42) cm volunteered and ran barefoot at 170 steps/minute over a force plate. Navicular drop measures were negatively correlated with tibial internal rotation excursion (r = −0.53, P = .01) but not with rearfoot eversion excursion (r = −0.19; P = .23). Significant positive correlations were found between navicular drop and peak knee adduction moment (r = .62, P < .01) and peak ankle inversion moment (r = .60, P < .01). These findings suggest that a low navicular drop measure could be associated with increasing tibial rotation excursion while high navicular drop measure could be associated with increased peak ankle and knee joint moments. These findings indicate that measures of navicular drop explained between 28% and 38% of the variability for measures of tibial internal rotation excursion, peak knee adduction moment and peak ankle inversion moments.

Restricted access

Bruce Elliott, J. Robert Grove and Barry Gibson

Eight international baseball pitchers were filmed in a laboratory while throwing from a pitching rubber attached to a Kistler force platform. Following a warm-up, all subjects threw fastballs (FB) until two strike pitches were assessed by an umpire positioned behind the catcher for both wind-up and set pitching techniques. Subjects then followed the same procedures for curveball pitches (CB). Both vertical (Z) and horizontal (Y) ground reaction force (GRF) data were recorded. A shutter correlation pulse was encoded so the temporal data from the film could be synchronized with the kinetic data from the force platform. Analysis of variance was used to analyze differences in force data at selected points in both pitching actions for both techniques. Vertical and horizontal GRFs increased from the first balance position to maximum levels at the cocked position for both techniques. Nonsignificant changes in GRF then occurred between the cocked position and front-foot landing. The Z GRFs were similar throughout the pitching action but higher in magnitude for the CB compared to the FB. Mean resultant forces were similar for the three fastest FB pitchers when compared to the three slowest pitchers. However, the slower group produced their peak resultant force earlier in the action, thus reducing the ability to drive over a stabilized front leg.