Search results for "Knee"
showing 10 items of 527 documents
Non-uniformity of displacement and strain within the Achilles tendon is affected by joint angle configuration and differential muscle loading.
2020
Although the Achilles tendon (AT) has been studied for more than a century, a complete understanding of the mechanical and functional consequences of AT structural organization is currently lacking. The aim of this study was to assess how joint angle configuration affects subtendon displacement and strain of soleus (SOL) and lateral gastrocnemius (LG) muscles. Knots sutured onto SOL and LG subtendons of 12 Wistar rats, were videotaped to quantify displacements and the ankle torque was assessed for different isometric activation conditions (i.e., individual and simultaneous) of the triceps surae muscles. Changing ankle and knee joint angle affected the magnitude of displacement, relative dis…
The Female Handball Player
2018
Female hormones fluctuate in concentrations during the menstrual cycle. This has triggered speculations among athletes, coaches, as well as researchers about the hormonal changes that lead to variations in athletic performance and adaptation to training. Many athletes, as in the general population, use oral contraceptives. This has raised questions concerning the suppression of the endogenous circulating female hormones and if the administration of synthetic hormones may have negative impact on athletic performance and training adaptations – or the opposite.
Sagittal Plane Hip, Knee, and Ankle Biomechanics and the Risk of Anterior Cruciate Ligament Injury: A Prospective Study
2018
Background: Stiff landings with less knee flexion and high vertical ground-reaction forces have been shown to be associated with an increased risk of anterior cruciate ligament (ACL) injury. The literature on the association between other sagittal plane measures and the risk of ACL injuries with a prospective study design is lacking. Purpose: To investigate the relationship between selected sagittal plane hip, knee, and ankle biomechanics and the risk of ACL injury in young female team-sport athletes. Study Design: Case-control study; Level of evidence, 3. Methods: A total of 171 female basketball and floorball athletes (age range, 12-21 years) participated in a vertical drop jump test usin…
Concentric force enhancement during human movement
2001
In order to understand the possible mechanisms contributing to enhanced concentric performance in stretch-shortening cycle exercises in vivo the present study examined knee extension torque, EMG activity and fascicle length of the vastus lateralis muscle in maximal and submaximal human movements. Maximal concentric knee extensions (120 s-1) were done after pre-stretch and pre-isometric conditions by nine volunteers. During shortening at the knee angle of 115 (180 = extended) the knee extension torque was found to be greater in pre-stretch condition (272 vs. 248 Nm, p < 0.05) although the torque level prior to shortening was smaller than in pre-isometric condition (268 vs. 314 Nm, p< 0.05…
Development of antibiotic loaded biodegradable matrices to prevent superficial infections associated to total knee arthroplasty.
2019
Abstract Development of a pharmaceutical form for the superficial infections related with arthroplasties would be helpful for clinical practice. In this context, we set out to evaluate ciprofloxacin and gentamicin elution from systems based on chitosan. Films and semisolid hydrogels containing chitosan alone (2%) or in combination with gelatin (6%) or different proportions (from 12% to 36%) of tetrakis-(hydroxymethyl)-phosphonium-chloride (THPC) were tested as delivery systems. Different antibiotic doses were assayed (0.5 mg/cm2,1 mg/cm2 and 2 mg/cm2). Antibiotic release was studied for each formulation. In vitro cytocompatibility studies and a simulation exercise for bioactivity evaluation…
Knee joint loading in the open and square stance tennis forehands
2013
Sandamas, Paul 2013. Knee joint loading in the open and square stance tennis forehands. Department of Biology of Physical Activity, University of Jyväskylä. Master's Thesis in Biomechanics. 80 pages. The aim of this study was to calculate and compare the resultant forces and moments in the knee joint of the open and square stance tennis forehands. An additional aim was to incorporate the ground reaction forces to shed light on the role of the lower body in aiding pelvic rotation in these two different forehands. The two types of forehand strokes hit by 7 right-handed university team level tennis players were filmed and the ground reaction forces on each foot were measured simultaneously. A …
Valore del segno del doppio legamento crociato posteriore nell'imaging con RM del ginocchio
2008
Questo studio è stato condotto in maniera retrospettiva su 2436 esami di risonanza magnetica (RM) di ginocchio eseguiti nel periodo compreso tra Gennaio 2006 e Ottobre 2007. Gli esami sono stati analizzati usando come unico criterio diagnostico per la definizione del segno del doppio legamento crociato posteriore (LCP) la visualizzazione diretta di un frammento in gola intercondiloidea parallelo ed inferiore al LCP. Tale segno è stato riscontrato in 56 casi, di cui 50 successivamente sottoposti ad artroscopia che ha confermato la diagnosi in tutti i casi. Tale segno è risultato pertanto altamente sensibile e specifico nella diagnosi di rotture meniscali a manico di secchio This study was ca…
Corticospinal and intracortical excitability is modulated in the knee extensors after acute strength training
2022
The corticospinal responses to high-intensity and low-intensity strength-training of the upper limb are modulated in an intensity-dependent manner. Whether an intensity-dependent threshold occurs following acute strength training of the knee extensors (KE) remains unclear. We assessed the corticospinal responses following high-intensity (85% of maximal strength) or low-intensity (30% of maximal strength) KE strength-training with measures taken during an isometric KE task at baseline, post-5, 30 and 60-min. Twenty-eight volunteers (23 ± 3 years) were randomized to high-intensity (n = 11), low-intensity (n = 10) or to a control group (n = 7). Corticospinal responses were evoked with transcra…
Changes in Muscle Activity Patterns and Joint Kinematics During Gait in Hemophilic Arthropathy
2020
Hemophilic arthropathy is the result of repetitive intra-articular bleeding and synovial inflammation. In people with hemophilic arthropathy (PWHA), very little is known about the neural control of individual muscles during movement. The aim of the present study was to assess if the neural control of individual muscles and coordination between antagonistic muscle pairs and joint kinematics during gait are affected in PWHA. Thirteen control subjects (CG) walked overground at their preferred and slow velocity (1 m/s), and 14 PWHA walked overground at the preferred velocity (1 m/s). Joint kinematics and temporal gait parameters were assessed using four inertial sensors. Surface electromyograph…
NEURAL CONTROL OF GAIT IN PEOPLE WITH HAEMOPHILIC ARTHROPATHY
2022
La hemofilia es un trastorno hemorrágico causado por una deficiencia de los factores VIII o IX de la coagulación. Las personas con hemofilia grave pueden tener hemorragias espontáneas o hemorragias en respuesta a traumatismos menores; la mayoría de los eventos ocurren en las articulaciones y los músculos. La manifestación clínica más frecuente es la artropatía hemofílica, que resulta del sangrado intraarticular repetitivo y de la membrana sinovial inflamada, lo que puede resultar en dolor crónico y deterioro articular. El objetivo general de mi tesis fue investigar el control neural de la marcha en personas con artropatía hemofílica (PCAH). La hipótesis de mi tesis fue que control neural de…