Search results for "Biomechanical"
showing 10 items of 524 documents
Static posturography with dynamic tests. Usefulness of biomechanical parameters in assessing vestibular patients.
2012
Abstract Introduction and objective Posturography allows us in evaluating postural control. This study showed the posturographic parameters that were useful for assessing the functional ability to maintain balance in our sample of vestibular patients. Material and methods Of a total of 89 patients, 59 were healthy subjects and 30 had a peripheral vestibular disorder. The subjects were studied using the posturographic NedSVE/IBV system, combining static (Romberg) and dynamic (stability limits and rhythmic weight shifts) tests. We then compared the measurements found in the groups. Results Normal subjects showed significantly lower oscillations than our patients in all of the posturographic p…
Multisectorial changes in the ciliary muscle during accommodation measured with high-resolution optical coherence tomography
2019
ABSTRACT Purpose: To measure changes in the anterior ciliary muscle during accommodation at the nasal, superior, temporal, and inferior sectors by means of an anterior chamber optical coherence tomographer, and correlate them with vergence changes. Methods: Twenty-four subjects with healthy, phakic eyes, whose mean age was 27.1 ± 8.9 years, underwent measurement with an anterior chamber optical coherence tomographer. The anterior ciliary muscle was measured at the nasal, temporal, superior, and inferior sectors for 0, -1, -2, and -3 D of vergence. A linear model was used to assess the correlation of each eye parameter with the accommodative demand. Results: The anterior ciliary muscle area …
Case study: effect of handrim diameter on performance in a paralympic wheelchair athlete.
2009
This study, with a top T-52 class athlete, determines the relationship between stroke frequency (SF) and push time (PT) and wheelchair velocity (Wv) using different handrim diameters (HD) and the effect of different HDs on the athlete’s heart rate (HR) and blood lactate (LACT) at competition speeds. Wv shows a linear-direct relationship with SF but a linear-inverse relationship with PT (p < .001 in both cases). Using bigger handrims (0.37 m instead of 0.36 m), SF increases 6%, while PT decreases 27% (at 24 Km·h–1). HR (p < .0001) increases with Wv and is also affected by HD with differences between the 0.34 m—0.36 m handrim group (lower values) and the 0.37 m handrim (higher values). …
Comparison of running kinematics between elite and national-standard 1500-m runners.
2009
The aim of this study was to determine whether elite 1500-m runners differ in their running kinematics from national-standard 1500-m runners. Six national-standard male runners (seasonal best: 3 min 49.2 s +/- 3.2 s) were assessed during the second lap of a 1500-m race. Their running kinematics was then compared with those of five elite runners (seasonal best: 3 min 35.6 s +/- 2.6 s) analysed during the second lap of the men's 1500-m final at the 2005 World Championships. Data were collected using two high-speed cameras operating at 200 Hz with a three-dimensional pan and tilt system. Running speed was the same for both groups. Despite the similar contact times, the minimum knee angle durin…
Achilles tendon stiffness is unchanged one hour after a marathon
2012
Overuse-induced injuries have been proposed as a predisposing factor for Achilles tendon (AT) ruptures. If tendons can be overloaded, their mechanical properties should change during exercise. Because there data are lacking on the effects of a single bout of long-lasting exercise on AT mechanical properties, the present study measured AT stiffness before and after a marathon. AT stiffness was determined as the slope of the force–elongation curve between 10 and 80% of maximum voluntary force. AT force–elongation characteristics were measured in an ankle dynamometer using simultaneous motion-capture-assisted ultrasonography. Oxygen consumption and ankle kinematics were also measured on a trea…
Isokinetic elbow flexion and coactivation following eccentric training.
1999
The influence of an eccentric training on torque/angular velocity relationships and coactivation level during maximal voluntary isokinetic elbow flexion was examined. Seventeen subjects divided into two groups (Eccentric Group EG, n = 9 Control Group CG, n = 8) performed on an isokinetic dynamometer, before and after training, maximal isokinetic elbow flexions at eight angular velocities (from - 120 degrees s(-1) under eccentric conditions to 240 degrees s(-1) under concentric conditions), and held maximal and submaximal isometric actions. Under all conditions, the myoelectric activities (EMG) of the biceps and the triceps brachii muscles were recorded and quantified as the RMS value. Eccen…
Continuous, bilateral Achilles' tendon vibration is not detrimental to human walk.
2001
Sensory feedback from the moving limbs contributes to the regulation of animal and human locomotion. However, the question of the specific role of the various modalities is still open. Further, functional loss of leg afferent fibres due to peripheral neuropathy does not always lead to major alteration in the gait pattern. In order to gain further insight on proprioceptive control of human gait, we applied vibratory tendon stimulation, known to recruit spindle primary afferent fibres, to both triceps surae muscles during normal floor walk. This procedure would disturb organisation and execution of walking, especially if spindles fire continuously and subjects are blindfolded. Vibration induc…
The Effects of a Prolonged Running Exercise on Strength Characteristics
2000
The aim of this study was to examine concentric, isometric, and eccentric strength reductions in the quadriceps muscle following a prolonged running exercise. Before and after a 2 h run (28.4+/-1.4 km) peak torque (PT) of the knee extensors at angular velocities of -120, -90, -60, 0, 60, 120, 180, 240 degrees x s(-1) using an isokinetic dynamometer, electromyographic (EMG) activity of the vastus lateralis (VL) and vastus medialis (VM) muscles and height of a counter movement jump were recorded in twelve well-trained triathletes. Counter movement jump performances decreased by 10% and PT values were all significantly lower (p < 0.01) at each angular velocity following the run. The torque los…
Effect of manual therapy versus proprioceptive neuromuscular facilitation in dynamic balance, mobility and flexibility in field hockey players. A ran…
2018
To compare the effectiveness of a specific Manual Therapy (MT) protocol applied to field hockey players (FHP), versus a Proprioceptive Neuromuscular Facilitation (PNF) protocol, in the improvement of dynamic balance, active range of movement and lumbar flexibility one-week and four-weeks after the treatment.Randomized controlled trial. Participants were assigned to 2 groups: MT and PNF. 30 min' sessions were performed once a week for three weeks. Three evaluations were performed: basal, one-week and four-weeks post-treatment.University of Valencia (Spain).22 in MT group and 20 in PNF group.Dynamic Balance, measured with Star Excursion Balance Test; Active Range of Motion (ROM), using a manu…
Acute effects of shock-type vibration transmitted to the hand-arm system.
1984
The aim of the project was to find out whether shock-type vibration of hand-tools compared to non-impulsive vibration has stronger acute effects on the hand-arm system and therefore needs a stricter evaluation from the occupational health point of view in comparison with the requirements of the Draft International Standard ISO-DIS 5349. Under laboratory conditions, subjects were exposed to simulated vibration of hand-tools (grinder, chain saw, hammer-drill, pneumatic hammer, rivet hammer and nailer). The following evaluation criteria were used: biomechanical transmissibility of the hand-arm system (wrist, elbow joint, shoulder joint); muscle-activity (m. flexor carpi ulnaris, m. biceps, m. …