Search results for "Biomechanical"
showing 10 items of 524 documents
Effects of treadmill running and fatigue on impact acceleration in distance running
2014
The effects of treadmill running on impact acceleration were examined together with the interaction between running surface and runner's fatigue state. Twenty recreational runners (11 men and 9 women) ran overground and on a treadmill (at 4.0 m/s) before and after a fatigue protocol consisting of a 30-minute run at 85% of individual maximal aerobic speed. Impact accelerations were analysed using two lightweight capacitive uniaxial accelerometers. A two-way repeated-measure analysis of variance showed that, in the pre-fatigue condition, the treadmill running decreased head and tibial peak impact accelerations and impact rates (the rate of change of acceleration), but no significant differenc…
Effect of 3 Weeks Use of Compression Garments on Stride and Impact Shock during a Fatiguing Run
2015
Excessive and prolonged exposure to impact acceleration during running is associated with increased injury rate. Acute use of compressive garments has been speculated to improve attenuation. However, it is unknown how longer interventions of compressive garments influence attenuation in running. 40 runners trained with compressive and placebo stockings for 3 weeks. Perception of comfort, stride parameters (rate, length) and impact acceleration (head and tibial peak acceleration, magnitude, acceleration rate and attenuation) were measured every 5 min during a fatigue run (30 min at 80% of the individual's maximal aerobic speed). Compressive stockings reduced tibial peak acceleration and magn…
Biomechanical factors affecting running economy.
2001
KYROLAINEN, H., A. BELLI, and P. V. KOMI. Biomechanical factors affecting running economy. Med. Sci. Sports Exerc., Vol. 33, No. 8, 2001, pp. 1330 -1337. Purpose: The present study was designed to investigate kinematics, kinetics, and muscle activity for explaining running economy at different running speeds. Methods: A total of 17 young endurance runners ran at 12-13 different running speeds. Respiratory gases were collected. Kinematic records were obtained by a high-speed video camera, and 3-D ground reaction forces (GRF) were measured simultaneously with telemetric EMG recordings of the selected leg muscles. In the analysis, joint moments and power were calculated by inverse dynamic meth…
Mechanical work and efficiency in treadmill running at aerobic and anaerobic thresholds
1990
Mechanical work, mechanical power, energy consumption and mechanical efficiency were studied in constant-speed treadmill running of 5 min at seven different exercises around aerobic (AerT) and anaerobic (AnT) thresholds. The true efficiency of concentric (positive) mechanical work and gross efficiency of the whole body in seven male subjects were calculated. The total mechanical work was calculated from film through the translational, potential and rotational energy states as the sum of the changes of all the mechanical energy states in all body segments allowing energy transfer between segments and from energy state to state. The total energy consumption was measured by combining aerobic a…
The posterior talocalcaneal ligament: an MRI evaluation
2020
Purpose Awideinter-individualvariabilityintermsofsize,orientationandinsertionisobservedregardingankleligaments. The aim of this study is to identify and describe the anatomical features of the posterior talocalcaneal ligament (PTCL) observed through the use of magnetic resonance imaging (MRI) of the ankle. Methods The study was retrospectively carried out on 893 ankle MRI’s exams. The exams have all been performed using a 1.5-T (T) MRI. The same scanning protocols and scan planes were carried out in all the exams. The first evaluated param- eter was the recognition of the PTCL. Subsequently, in all those cases where the ligament was present, its features such as insertion sites, length, and…
A hierarchical cluster analysis to determine whether injured runners exhibit similar kinematic gait patterns
2020
Previous studies have suggested that runners can be subgrouped based on homogeneous gait patterns, however, no previous study has assessed the presence of such subgroups in a population of individuals across a wide variety of injuries. Therefore, the purpose of this study was to assess whether distinct subgroups with homogeneous running patterns can be identified among a large group of injured and healthy runners and whether identified subgroups are associated with specific injury location. Three‐dimensional kinematic data from 291 injured and healthy runners, representing both sexes and a wide range of ages (10‐66 years) was clustered using hierarchical cluster analysis. Cluster analysis r…
Biomechanical and skeletal muscle determinants of maximum running speed with aging.
2009
Purpose: Aging diminishes the ability to run fast, but the specific mechanisms responsible for this deterioration remain largely unknown. In the present study, we investigated the age-related decline in sprint running ability through a cross-sectional examination of biomechanical and skeletal muscle characteristics in 77 competitive male sprinters aged 17-82 yr. Methods: Ground reaction force (GRF) and kinematic stride cycle parameters were measured during the maximum-velocity phase using a 9.4-m-long force platform. Knee extensor (KE) and ankle plantar flexor (PF) structural characteristics were investigated using ultrasonography and muscle biopsies (vastus lateralis). Force production cha…
The influence of ageing on the force-velocity-power characteristics of human elbow flexor muscles.
2003
Abstract The purpose of this study was to quantify the effects of ageing on the maximal power ( P max ) of the elbow flexor muscles and to determine the impact of velocity on the loss of power in older people. Sixteen elderly subjects (7 men and 9 women, age range 61–78 years) and 17 young subjects (11 men and 6 women, age range 18–27 years) participated in this study. Maximal elbow flexions were performed against increasing inertia. The maximal force ( F max ), maximal shortening velocity ( V max ), P max , dynamic constants ( a , b and a / F max ), optimal force ( F opt ), optimal velocity ( V opt ) and V opt / V max were determined from Hill's equation. Myoelectrical activity (EMG) of th…
Muscle activation during cycling at different cadences: Effect of maximal strength capacity
2007
International audience; The purpose of this study was to examine the influence of maximal strength capacity on muscle activation, during cycling, at three selected cadences: a low cadence (50 rpm), a high cadence (110 rpm) and the freely chosen cadence (FCC). Two groups of trained cyclists were selected on the basis of the different maximal isokinetic voluntary contraction values (MVCi) of their lower extremity muscles as follow: Fmin (lower MVCi group) and Fmax (higher MVCi group). All subjects performed three 4-min cycling exercises at a power output corresponding to 80 % of the ventilatory threshold under the three cadences. Neuromuscular activity of vastus lateralis (VL), rectus femoris…
Isokinetic strength and anaerobic power of elite, subelite and amateur French soccer players.
2001
Information about the influence of different practice levels on physical characteristics of a large number of soccer players is lacking. Therefore we assessed muscular strength and anaerobic power of elite, subelite and amateur soccer players to clarify what parameters distinguish the top players from the less successful. We tested 95 soccer players from the French first division (elite), second division (subelite), and amateurs and determined the isokinetic strength of the knee extensor and flexor muscles at angular velocities from -120 degrees x s(-1) to 300 degrees x s(-1). Vertical jump, 10 m sprint, 30 m sprint and maximum ball speed during shooting were also measured. The elite player…