Search results for " stiffness"
showing 10 items of 299 documents
Variable association of 24-h peripheral and central hemodynamics and stiffness with hypertension-mediated organ damage: the VASOTENS Registry.
2020
Objective In this analysis of the telehealth-based Vascular health ASsessment Of The hypertENSive patients Registry, we checked how 24-h central and peripheral hemodynamics compare with hypertension-mediated organ damage (HMOD). Methods In 646 hypertensive patients (mean age 52 ± 16 years, 54% males, 65% treated) we obtained ambulatory brachial and central SBP and pulse pressure (PP), SBP, and PP variability, pulse wave velocity and augmentation index with a validated cuff-based technology. HMOD was defined by an increased left ventricular mass index (cardiac damage, evaluated in 482 patients), an increased intima-media thickness (vascular damage, n = 368), or a decreased estimated glomerul…
Insulin-resistance HCV infection-related affects vascular stiffness in normotensives
2015
BACKGROUND AND AIMS. Arterial stiffness evaluated as pulse wave velocity, is an early marker of vascular damage and an independent predictor for cardiovascular events. We investigated if the insulin resistance/hyperinsulinemia chronic hepatitis C virus infection-related could influence arterial stiffness. METHODS. We enrolled 260 outpatients matched for age, body mass index, gender, ethnicity: 52 with never-treated uncomplicated chronic hepatitis C virus infection (HCV(+)), 104 never-treated hypertensives (HT) and 104 healthy subjects (NT). Pulse wave velocity was evaluated by a validated system employing high-fidelity applanation tonometry. We also measured: fasting plasma glucose and insu…
Localization of Muscle Edema and Changes on Muscle Contractility After Dry Needling of Latent Trigger Points in the Gastrocnemius Muscle.
2019
Background Myofascial trigger points (TrPs) are hyperirritable spots within taut bands of skeletal muscles that elicit local and referred pain when stimulated. Among the variety of techniques used for treating TrPs, dry needling (DN) is the most commonly applied intervention. The physiological mechanisms underlying the effects of DN remain to be elucidated. Objective To examine changes in skeletal muscle after DN in the area where the TrP is located. Methods We measured in vivo changes that occur in human skeletal muscle one hour after DN over a TrP with magnetic resonance imaging (MRI) and tensiomyography. The study included 18 asymptomatic subjects with a latent TrP in one medial gastrocn…
Effect of nighttime aircraft noise exposure on endothelial function and stress hormone release in healthy adults.
2013
Aims Aircraft noise disturbs sleep, and long-term exposure has been shown to be associated with increases in the prevalence of hypertension and an overall increased risk for myocardial infarction. The exact mechanisms responsible for these cardiovascular effects remain unclear. Methods and results We performed a blinded field study in 75 healthy volunteers (mean age 26 years), who were exposed at home, in random order, to one control pattern (no noise) and two different noise scenarios [30 or 60 aircraft noise events per night with an average maximum sound pressure level (SPL) of 60 dB(A)] for one night each. We performed polygraphy during each study night. Noise caused a worsening in sleep…
Interaction between pre-landing activities and stiffness regulation of the knee joint musculoskeletal system in the drop jump: implications to perfor…
2002
The purpose of the present study was to investigate the interaction between the pre-landing activities and the stiffness regulation of the knee joint musculoskeletal system and the takeoff speed during a drop jump (DJ). Nine healthy male subjects performed a DJ test from the height of 50 cm. The surface electromyographic (EMG) activity of the vastus lateralis (VL) muscle was recorded to evaluate both the pre-landing and post-landing muscle activation levels. Simultaneous recording of the jumping motion and ground reaction force was performed by a high-speed video camera (100 frames x s(-1)), and a force platform was employed to allow joint moment analysis. Joint stiffness was calculated by …
Running in highly cushioned shoes increases leg stiffness and amplifies impact loading
2018
AbstractRunning shoe cushioning has become a standard method for managing impact loading and consequent injuries due to running. However, despite decades of shoe technology developments and the fact that shoes have become increasingly cushioned, aimed to ease the impact on runners’ legs, running injuries have not decreased. To better understand the shoe cushioning paradox, we examined impact loading and the spring-like mechanics of running in a conventional control running shoe and a highly cushioned maximalist shoe at two training speeds, 10 and 14.5 km/h. We found that highly cushioned maximalist shoes alter spring-like running mechanics and amplify rather than attenuate impact loading. T…
Postactivation potentiation can counteract declines in force and power that occur after stretching.
2016
Stretching can decrease a muscle's maximal force, whereas short but intense muscle contractions can increase it. We hypothesized that when combined, postactivation potentiation induced by reactive jumps would counteract stretch-induced decrements in drop jump (DJ) performance. Moreover, we measured changes in muscle twitch forces and ankle joint stiffness (KAnkle ) to examine underlying mechanisms. Twenty subjects completed three DJs and 10 electrically evoked muscle twitches of the triceps surae subsequent to four different conditioning activities and control. The conditioning activities were 10 hops, 20s of static stretching of the triceps surae muscle, 20s of stretching followed by 10 ho…
Mechanical efficiency of locomotion in females during different kinds of muscle action
1990
The mechanical efficiencies (ME) of pure positive and pure negative work as well as of stretch-shortening cycle (SSC) exercise were investigated with a special sledge apparatus. The subjects were 20 young females who performed six different types of submaximal exercise: two of pure concentric exercise (positive work), two of pure eccentric exercise (negative work) and two SSC exercises. The work intensities were determined individually, from the recordings of distance obtained during a single maximal concentric exercise. Each exercise involved 60 muscle actions lasting a total of 3 min per testing condition. The MEs of pure positive work with intensities of 30% and 60% maximum (C30 and C60 …
Acute and prolonged reduction in joint stiffness in humans after exhausting stretch-shortening cycle exercise.
2002
The purpose of the present study was to examine the acute and long-term fatigue effects of exhausting stretch-shortening cycle (SSC) exercise on the stiffness of ankle and knee joints. Five subjects were fatigued on a sledge apparatus by 100 maximal rebound jumps followed by continuous submaximal jumping until complete exhaustion. Neuromuscular fatigue ef- fects were examined in submaximal hopping (HOP) and in maximal drop jumps (DJ) from 35 (DJ35) and 55 cm (DJ55) heights on a force plate. Additional force and reflex measurements were made using an ankle ergom- eter. Jumping tests and ankle ergometer tests were car- ried out before, immediately after, 2 h (2H), 2 days and 7 days (7D) after…
Associations of Sex Hormones and Hormonal Status With Arterial Stiffness in a Female Sample From Reproductive Years to Menopause
2021
Objective: Loss of sex hormones has been suggested to underlie menopause-associated increment in cardiovascular risk. We investigated associations of sex hormones with arterial stiffness in 19–58-years-old women. We also studied associations of specific hormonal stages, including natural menstrual cycle, cycle with combined oral contraceptives (COC) and menopausal status with or without hormone therapy (HT), with arterial stiffness. Methods: This study includes repeated measurements of 65 healthy women representing reproductive (n=16 natural, n=10 COC-users) and menopause (n=5 perimenopausal, n=26 postmenopausal, n=8 HT-users) stages. Arterial stiffness outcomes were aortic pulse wave veloc…