Search results for "Muscle"
showing 10 items of 3397 documents
STRENGTH AND POWER PROFILES OF THE LOWER AND UPPER EXTREMITIES IN MASTER THROWERS AT DIFFERENT AGES
2007
Ojanen, T., T. Rauhala, and K. Hakkinen. Strength and power profiles of the lower and upper extremities in master throwers at different ages. J. Strength Cond. Res. 21(1):216-222. 2007.-Thirty-two master athletes (shot put, discus, and hammer throw) were divided into 4 groups according to their age (T40 [40 years of age], 50 [50 years of age], 60 [60 years of age], and 75 [75 years of age]). Twenty-eight age-matched men served as controls (C40 [40 years of age], 50 [50 years of age], 60 [60 years of age], and 75 [75 years of age]). The subjects were tested for maximal isometric strength of the lower and upper extremities. Power was measured by performing jump squats and bench press in the S…
Maximal force, force/time and activation/coactivation characteristics of the neck muscles in extension and flexion in healthy men and women at differ…
2002
This study examined the force production characteristics, activation/coactivation and endurance capacity of the neck extension and flexion muscles in healthy men (n=29) and women (n=28) divided into three age groups (18–26 years, 30–37 years and 45–55 years). Force and electromyography (EMG) measurements were performed during the maximal voluntary isometric extension and flexion actions. This was followed by an endurance test (ET; 60% force level of maximal voluntary contraction sustained until exhaustion), after which the force and EMG recordings were repeated. Men were both stronger and had higher values (P<0.001) for explosive force (rate of force development, RFD) than women in both act…
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…
Heavy resistance exercise training and skeletal muscle androgen receptor expression in younger and older men
2010
Effects of heavy resistance exercise on serum testosterone and skeletal muscle androgen receptor (AR) concentrations were examined before and after a 21-week resistance training period. Seven healthy untrained young adult men (YT) and ten controls (YC) as well as ten older men (OT) and eight controls (OC) volunteered as subjects. Heavy resistance exercise bouts (5 × 10 RM leg presses) were performed before and after the training period. Muscle biopsies were obtained before and 1h and 48 h after the resistance exercise bouts from m.vastus lateralis (VL) to determine cross-sectional area of muscle fibers (fCSA) and AR mRNA expression and protein concentrations. No changes were observed in YC …
Age-related muscle activation profiles and joint stiffness regulation in repetitive hopping
2011
Abstract It is well documented that increasing effort during exercise is characterized by an increase in electromyographic activity of the relevant muscles. How aging influences this relationship is a matter of great interest. In the present study, nine young and 24 elderly subjects did repetitive hopping with maximal effort as well as with 50%, 65%, 75% and 90% intensities. During hopping joint kinematics were measured together with electromyographic activity (EMG) from the soleus, gastrocnemius medialis, gastrocnemius lateralis and tibialis anterior muscles. The results showed that agonist activation increased in both age groups with increasing intensity. The highest jumping efficiency (E…
V2-receptor–mediated relaxation of human renal arteries in response to desmopressin
1999
The effects of deamino-8-D-arginine vasopressin (desmopressin), a V2 receptor antidiuretic agonist, were studied in isolated rings from branches of renal arteries obtained from 22 patients undergoing nephrectomy. The rings were suspended in organ bath chambers for isometric recording of tension. In precontracted rings with norepinephrine (10(-6) to 3 x 10(-6) mol/L), desmopressin (10(-11) to 3 x 10(-7) mol/L) caused endothelium-dependent relaxation (81%+/-4% reversal of the initial contraction in arteries with endothelium; 20%+/-4% in arteries without endothelium; P < .05). The relaxation to desmopressin in rings with endothelium was reduced significantly by indomethacin (10(-6) mol/L) and …
The difficulty of the postural control task affects multi-muscle control during quiet standing
2016
The aim of this study was to compare the electromyographic (EMG) coherence between the lower limb and the core muscles when carrying out two postural tasks at different difficulty levels. EMG was recorded in 20 healthy male subjects while performing two independent quiet standing tasks. The first one involved a bipedal stance with the eyes open, while the second consisted of a dominant unipedal stance also with the eyes open. The obtained EMG signals were analysed by computing estimations of EMG–EMG coherence between muscle pairs, both singly (single-pair estimations) and combined (pooled estimations). Pooled and single coherence of anterior, posterior, core, antagonist and mixed pairs of m…
Clinical significance of autoantibodies to soluble liver antigen in autoimmune hepatitis.
1999
Abstract Background/Aims: Classification of autoimmune hepatitis (AIH) into different subgroups according to autoantibody status has been proposed: type I (ANA/SMA), type II (LKM-1) and type III (anti-SLA). However, whether type III AIH forms a clinically distinct disease entity remains controversial. The aim of this study was to evaluate the subclassification of AIH into ANA/SMA and anti-SLA positive patients with regard to clinical, biochemical and histologic differences. Methods: Ninety-seven consecutive patients with a well-documented long-term course of AIH with ANA/SMA and/or anti-SLA autoantibodies were studied. Clinical, biochemical and histological features of patients with ANA/SMA…
NEUROMUSCULAR PERFORMANCE CHARACTERISTICS OF OPEN-WHEEL AND RALLY DRIVERS
2005
The purpose of the present study was to investigate neuromuscular performance characteristics in open-wheel and rally drivers using the cross-sectional study design. The subjects (N = 28) consisted of experienced international-level open-wheel drivers (n = 9), experienced international-level rally drivers (n = 9) and a physically active nondriving male control group (n = 10). In 3 separate test sessions, speed, muscle strength, and endurance tests were performed. The rally drivers had higher (p < 0.05) grip, shoulder flexion, and ankle plantar flexion strength, as compared to the control group. The open-wheel drivers showed higher strengths (p < 0.05) than the controls in neck forces, grip,…
Central correlation of muscle sympathetic nerve activation during baroreflex unloading - a microneurography-positron emission tomography study
2013
The baroreceptor reflex controls spontaneous fluctuations in blood pressure. One major control variable of the baroreflex is the sympathetic vasoconstrictor activity to muscles [MSNA; burst frequency (BF) and burst incidence (BI)], which can be quantitatively assessed by microneurography. We aimed to investigate the central regions involved in baroreflex regulation of MSNA. Healthy men (mean age 25 years) participated in three experimental sessions. (i) Microneurography recordings of MSNA from the left peroneal nerve during rest and baroreflex unloading, induced by lower body negative pressure (LBNP; -40 mmHg). If MSNA could be reliably recorded throughout this procedure (n = 15), the subje…