Search results for "Mechanical Phenomena"
showing 10 items of 532 documents
Muscle-tendon glucose uptake in Achilles tendon rupture and tendinopathy before and after eccentric rehabilitation: Comparative case reports
2016
Achilles tendon rupture (ATR) is the most common tendon rupture injury. The consequences of ATR on metabolic activity of the Achilles tendon and ankle plantarflexors are unknown. Furthermore, the effects of eccentric rehabilitation on metabolic activity patterns of Achilles tendon and ankle plantarflexors in ATR patients have not been reported thus far. We present a case study demonstrating glucose uptake (GU) in the Achilles tendon, the triceps surae, and the flexor hallucis longus of a post-surgical ATR patient before and after a 5-month eccentric rehabilitation. At baseline, three months post-surgery, all muscles and Achilles tendon displayed much higher GU in the ATR patient compared to…
Influence of the distance in a roundhouse kick's execution time and impact force in Taekwondo.
2009
Taekwondo, originally a Korean martial art, is well known for its kicks. One of the most frequently used kicks in competition is Bandal Chagui or roundhouse kick. Excellence in Taekwondo relies on the ability to make contact with the opponent's trunk or face with enough force in as little time as possible, while at the same time avoiding being hit. Thus, the distance between contestants is an important variable to be taken into consideration. Thirty-one Taekwondo athletes in two different groups (expert and novice, according to experience in competition) took part in this study. The purpose of this study was to examine both impact force and execution time in a Bandal Chagui or roundhouse ki…
Initiating running barefoot: Effects on muscle activation and impact accelerations in habitually rearfoot shod runners
2016
Runners tend to shift from a rearfoot to a forefoot strike pattern when running barefoot. However, it is unclear how the first attempts at running barefoot affect habitually rearfoot shod runners. Due to the inconsistency of their recently adopted barefoot technique, a number of new barefoot-related running injuries are emerging among novice barefoot runners. The aim of this study was therefore to analyse the influence of three running conditions (natural barefoot [BF], barefoot with a forced rearfoot strike [BRS], and shod [SH]) on muscle activity and impact accelerations in habitually rearfoot shod runners. Twenty-two participants ran at 60% of their maximal aerobic speed while foot strik…
Effect of aneurysm on the mechanical dissection properties of the human ascending thoracic aorta
2012
Objectives: The acute dissection of an ascending thoracic aortic aneurysm (ATAA) represents a devastating separation of elastic layers occurring when the hemodynamic loads on the diseased wall exceed the adhesive strength between layers. At present, the mechanics underlying aortic dissection are largely unclear, and the biomechanical delamination properties of the aneurysmal aorta are not defined. Individuals with bicuspid aortic valve (BAV) are particularly predisposed to ascending aortic aneurysm formation, with a marked risk of aortic dissection. The purpose of this study was to evaluate and compare the dissection properties of nonaneurysmal and aneurysmal human ascending thoracic aorta …
Ski jumping boots limit effective take-off in ski jumping
2002
In this study, we measured the vertical and horizontal take-off forces, plantar pressures and activation patterns of four muscles (vastus lateralis, gluteus maximus, tibialis anterior, gastrocnemius) in 10 ski jumpers in simulated laboratory conditions when wearing either training shoes or ski jumping boots. We found significant differences in vertical (P < 0.001), horizontal (P < 0.05) and resultant (P < 0.001) take-off velocities and vertical force impulse (P < 0.01). We found no significant differences in the jumpers' initial take-off positions; however, the jumping boots condition resulted in a smaller displacement in the final position of the following joint angles: ankle angle (P < 0.…
Functional evaluation of patients with anterior cruciate ligament injury. A transversal analytical study.
2018
Abstract Objective To evaluate, by means of biomechanical analysis, functional alterations of gait and balance of patients with anterior cruciate ligament (ACL) injury. Material and methods Transversal analytical study on 64 people, 27 health subjects and 37 patients with ACL injury. Biomechanical analysis of gait in all individuals was performed by means of four tests: (1) kinematic test, to characterize gait pattern; (2) kinetic test, to characterize forces against the floor, duration of treads, symmetry of both legs, and the reproducibility of the gait; (3) pivot-shift test, to analyze the rotational stability of the knee on the sagittal axis; and (4) equilibrium test. Results Alteration…
Stability of the upper neck during isometric neck exercises in rheumatoid arthritis patients with atlantoaxial disorders.
2008
To study the effect of isometric neck strength exercises on upper cervical stability in patients with rheumatoid arthritis (RA).Twenty patients with a mean (SD) age of 58 (9) years and duration of RA of 27 (10) years volunteered for the study. Lateral radiographs of the cervical spine were taken to measure the current atlantoaxial distance (AAD) in flexion and extension. Maximal isometric neck flexion and extension strength values were measured by a dynamometer. Thereafter, AADs were measured from radiographs taken at 80-90% resistance of maximal strength.According to the full flexion radiographs at baseline, the patients were classified into three groups: eight patients without anterior at…
Kinematic parameters after tibial nonunion treatment using the Ilizarov method
2021
Abstract Background Analysis of the outcomes of Ilizarov treatment of tibial nonunion shows functional deficits in the lower limbs of some patients. Biomechanical gait parameters are an important measure for assessing musculoskeletal disorder treatments that aim to restore normal gait. The purpose of our study was to compare the kinematic parameters in patients with tibial nonunion treated using the Ilizarov method and those in a control group of healthy volunteers. Methods The study population consisted of 23 patients (age 54.9 ± 16.4 years) who were treated for tibial nonunion using the Ilizarov method, as well as 22 healthy adult controls (age 52.7 ± 10.6 years). Kinematic parameters wer…
Acute effect of induced asymmetrical running technique on foot skin temperature
2020
The aim of the study was to evaluate skin temperature of the soles of the feet before and after a provoked asymmetrical running. Seventeen recreational male runners performed two 15 min running tests in the same session. In the first test, participants performed running without modifying their running technique (control condition). In the second running test, they repeated the same protocol using an ankle weight of 1.5 kg in the non-dominant ankle (asymmetrical condition). Rate of perceive exertion, heart rate and spatio-temporal parameters were measured during the running tests. Skin temperature was measured with an infrared camera before and after each condition. Generally, comparing both…
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…