Search results for "BIOMECHANICS"
showing 10 items of 281 documents
Human voice pitch measures are robust across a variety of speech recordings: methodological and theoretical implications
2021
Fundamental frequency ( f o ), perceived as voice pitch, is the most sexually dimorphic, perceptually salient and intensively studied voice parameter in human nonverbal communication. Thousands of studies have linked human f o to biological and social speaker traits and life outcomes, from reproductive to economic. Critically, researchers have used myriad speech stimuli to measure f o and infer its functional relevance, from individual vowels to longer bouts of spontaneous speech. Here, we acoustically analysed f o in nearly 1000 affectively neutral speech utterances (vowels, words, counting, greetings, read paragraphs and free spontaneous speech) produced by the same 154 men and women, ag…
Influence of the structural components of artificial turf systems on impact attenuation in amateur football players
2019
AbstractThe purpose of this research was to evaluate the influence of the structural components of different 3rd generation artificial turf football field systems on the biomechanical response of impact attenuation in amateur football players. A total of 12 amateur football players (24.3 ± 3.7 years, 73.5 ± 5.5 kg, 178.3 ± 4.1 cm and 13.7 ± 4.3 years of sport experience) were evaluated on three third generation artificial turf systems (ATS) with different structural components. ATS were composed of asphalt sub-base and 45 mm of fibre height with (ATS1) and without (ATS2) elastic layer or compacted granular sub-base, 60 mm of fibre height without elastic layer (ATS3). Two triaxial accelerome…
Symmetry function in gait pattern analysis in patients after unilateral transfemoral amputation using a mechanical or microprocessor prosthetic knee
2021
AbstractBackgroundAbove-knee amputations (AKAs) contribute to gait asymmetry. The level of asymmetry is affected by the type of knee prosthetic module. There is limited evidence suggesting that more technically advanced solutions (microprocessor modules; MicPK) are superior to less advanced ones (mechanical modules; MechPK). The study aimed to evaluate the variable range of hip and pelvic joint movements during gait and look for differentiating areas with an increased level of asymmetry of the gait cycle in individuals who underwent an AKA and are equipped with MicPK or MechPK.MethodsTwenty-eight individuals participated in the study; 14 were assigned to a study group of individuals who und…
Biomechanics of simulated versus natural cross-country sit skiing
2017
The purpose of this study was to investigate the biomechanics of cross-country sit-skiing in simulated and natural skiing. Thirteen international level athletes participated in a ski ergometer test (simulated conditions) and a test on snow in a ski-tunnel (natural conditions) using their personal sit-ski. Tests in both conditions were performed at individual maximal speed. When comparing the two conditions the main results were: (1) maximal speed in simulated conditions was lower (p < 0.05) but correlated well with the natural condition (r = 0.79, p < 0.001); (2) no differences in pole force variables were found; peak force (r = 0.77, p < 0.01) and average force (r = 0.78, p < 0.01) correla…
Effect of age in the ciliary muscle during accommodation: Sectorial analysis
2017
Abstract Purpose To compare changes in the ciliary muscle area at different sectors between pre-presbyopic and presbyopic eyes during accommodation by means of an anterior segment optical coherence tomographer (OCT). Methods The anterior ciliary muscle area was measured in 20 healthy and phakic pre-presbyopic eyes, whose mean age was 23.3 ± 4.4 years, and in 20 healthy and phakic presbyopic eyes, whose mean age was 46.5 ± 5.2 years. The relative change in the cross-sectional area of the ciliary muscle was measured at the nasal, inferior, and temporal sectors between 0 and −3 D of vergence, in −1 D step. A linear model was used to assess the correlation of each eye parameter with the accommo…
Strength characteristics of a healthy urban adult population
1991
A random sample of 778 subjects representing ages 25, 35, 45 and 55 years were studied for the amount of habitual physical activity, their anthropometric structure, vertical jumping height, trunk extension and flexion torques and dynamic endurance fitness of trunk extension and flexion. The proportion of subjects who were habitually physically active did not change systematically with age. The highest number of physically inactive subjects was found in men and women in the 35-year age group. The results in all the tests used to assess the strength characteristics were statistically significant when related to sex (P less than 0.001) and in all, except the relative maximal isometric torque o…
Technical determinants of biathlon standing shooting performance before and after race simulation
2018
The aim of this study was to identify performance- determining factors in biathlon standing shooting in rest and after intense exercise. Eight Finnish national- and nine junior- team biathletes participated in the study. Participants fired 40 resting shots (REST) and 2 × 5 competition simulation shots (LOAD) after 5 minutes of roller skiing at 95% of peak heart rate. Hit percentage, aiming point trajectory and postural balance were measured from each shot. Cleanness of triggering (ATV, movement of the aiming point 0- 0.2 second before the shot) and vertical stability of hold (DevY) were the most important components affecting shooting performance both in REST (DevY, R = −0.61, P < .01; ATV,…
Differential contributions of ankle plantarflexors during submaximal isometric muscle action: A PET and EMG study
2014
Abstract The objective of this study was to investigate the relative contributions of superficial and deep ankle plantarflexors during repetitive submaximal isometric contractions using surface electromyography (SEMG) and positron emission tomography (PET). Myoelectric signals were obtained from twelve healthy volunteers (27.3±4.2yrs). A tracer ([ 18 F]-FDG) was injected during the exercise and PET scanning was done immediately afterwards. The examined muscles included soleus (Sol), medial gastrocnemius (MG), lateral gastrocnemius (LG), and flexor hallucis longus (FHL). It was found that isometric maximal voluntary contraction (MVC) force, muscle glucose uptake (GU) rate, and SEMG of variou…
The Temporal Structure of Vertical Arm Movements
2011
Import JabRef | WosArea Life Sciences and Biomedicine - Other Topics; International audience; The present study investigates how the CNS deals with the omnipresent force of gravity during arm motor planning. Previous studies have reported direction-dependent kinematic differences in the vertical plane; notably, acceleration duration was greater during a downward than an upward arm movement. Although the analysis of acceleration and deceleration phases has permitted to explore the integration of gravity force, further investigation is necessary to conclude whether feedforward or feedback control processes are at the origin of this incorporation. We considered that a more detailed analysis of…
Effects of grip and push forces on the acute response of the hand-arm system under vibrating conditions
1993
The purpose of the occupational medicine component of a joint research project was to study the effects of grip and push forces on the acute reaction of the hand-arm system under vibrating conditions. Several series of experiments were carried out by means of a vibration simulator in a laboratory environment in order to study biodynamic vibration behaviour, muscle response, skin temperature, shifts of the vibration perception threshold and the intensity of subjective vibration perception; in addition, field tests with hammer drills were conducted. On the whole, the findings obtained suggest that the coupling of the hand with the handle involved in using vibrating tools has a considerable im…