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
Talita Molinari, Tainara Steffens, Cristian Roncada, Rodrigo Rodrigues and Caroline P. Dias
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
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
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.
George Vagenas and Blaine Hoshizaki
This study investigated the phenomenon of lower extremity functional asymmetries in a group of competitive male distance runners (N = 29). Bilateral measurements were taken to assess selected variables of the talocalcaneal flexibility (goniometry) and of the isokinetic knee strength (Cybex II). Data analysis revealed significant asymmetries for both lower extremity functional parameters. The subjects were symmetric in the total range of motion of the subtalar joint and inversely asymmetric in the range of motion of calcaneal eversion and calcaneal inversion. The laterality patterns of functional asymmetries were found to be consistent and independent of the conventional upper and lower extremity lateral preferences. It was theorized that asymmetries in the lower extremities are characterized by joint-specific trends of bilateralism.
Yaara Nadiv, Ricki Vachbroit, Amit Gefen, David Elad, Uri Zaretsky, Dani Moran, Pinchas Halpern and Anat Ratnovsky
The respiratory muscles may fatigue during prolonged exercises and thereby become a factor that limits extreme physical activity. The aim of the current study was to determine whether respiratory muscle fatigue imposes a limitation on extreme physical activity of well-trained young men. Electromyography (EMG) signals of respiratory (external intercostal and sternomastoid) and calf muscles (gastrocnemius) were measured (N = 8) during 1 hr of treadmill marching at a speed of 8 km/hr with and without a 15 kg backpack. The root mean square (RMS) and the mean power frequency of the EMG signals were evaluated for calculating fatigue indices. The EMG RMS revealed that the respiratory and calf muscles did not fatigue during the marching without a backpack load. The study did show, however, a significant rise in the EMG values when a backpack was carried with respect to the no-load condition (p < .05), which suggests that respiratory muscles should be trained in military recruits who are required to carry loaded backpacks while marching.
Renato Rodano and Roberto Squadrone
Stability and consistency is a critical aspect in joint kinetic measurements. By applying a statistical technique, called sequential estimation procedure, the aim of this work was to determine the minimum number of trials required to obtain a stable mean for peak hip, knee, and ankle moments and powers during vertical jump. Nine competitive track and field sprinters (21.7 ± 3.5 yrs, 177.6 ± 4.3 cm, 70.8 ± 3.6 kg) performed 5 series of 5 double-legged maximum-height countermovement vertical jumps. From force platform and kinematic data, moment and power output were calculated for hip, knee, and ankle joints. The sequential estimation procedure applied to these data revealed that at least a 12-trial protocol is needed to establish a true measure for all the selected parameters. The mean number of trials for each variable was greater than 8 and less than 13. When hip moments were excluded from the analysis, a 10-trial protocol could be sufficient to reach a stable mean. In conclusion. the results of this study gave statistical evidence for the need to adopt multiple-trial protocols in order to obtain a stable mean for joint kinetic data.
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.
Stephanie Chester, Audrey Zucker-Levin, Daniel A. Melcher, Shelby A. Peel, Richard J. Bloomer and Max R. Paquette
The purpose of this study was to compare knee and hip joint kinematics previously associated with anterior knee pain and metabolic cost among conditions including treadmill running (TR), standard elliptical (SE), and lateral elliptical (LE) in healthy runners. Joint kinematics and metabolic parameters of 16 runners were collected during all 3 modalities using motion capture and a metabolic system, respectively. Sagittal knee range of motion (ROM) was greater in LE (P < .001) and SE (P < .001) compared with TR. Frontal and transverse plane hip ROM were greater in LE compared with SE (P < .001) and TR (P < .001). Contralateral pelvic drop ROM was smaller in SE compared with TR (P = .002) and LE (P = .005). Similar oxygen consumption was found during LE and TR (P = .39), but LE (P < .001) and TR (P < .001) required greater oxygen consumption than SE. Although LE yields similar metabolic cost to TR and produces hip kinematics that may help strengthen hip abductors, greater knee flexion and abduction during LE may increase symptoms in runners with anterior knee pain. The findings suggest that research on the implications of elliptical exercise for injured runners is needed.
Margaret K.Y. Mak, Oron Levin, Joseph Mizrahi and Christina W.Y. Hui-Chan
Calculation of joint torques during the rising phase of sit-to-stand motion is in most cases indeterminate, due to the unknown thighs/chair reaction forces in addition to the other sources of uncertainties such as joint positioning and anthropometric data. In the present study we tested the reliability of computation of the joint torques from a five-segment model; we used force plate data of thighs/chair and feet/ground reaction forces, in addition to kinematic measurements. While solving for joint torques before and after seat-off, differences between model solutions and measured data were calculated and minimized using an iterative algorithm for the reestimation of joint positioning and anthropometric properties. The above method was demonstrated for a group of six normal elderly persons.