Search results for "Quadriceps Muscle"
showing 10 items of 80 documents
Postmenopausal women with osteopenia and a healed wrist fracture have reduced physical function and quality of life compared to a matched, healthy co…
2013
Background Fractures lead to reduced physical function and quality of life (QOL), but little is known about postmenopausal women with osteopenia and a healed wrist fracture. The purpose was to evaluate physical function in terms of quadriceps strength, dynamic balance, physical capacity and QOL in postmenopausal women with osteopenia and a healed wrist fracture compared to a matched, healthy control group with no previous fracture. Methods Eighteen postmenopausal women with osteopenia (patients) (mean age 59.1 years, range 54 – 65) and a healed wrist fracture were matched to 18 healthy control subjects on age (mean age 58.5 years, range 51 – 65), height, weight and body mass index (BMI). We…
Differences in cardiorespiratory and neuromuscular responses between voluntary and stimulated contractions of the quadriceps femoris muscle.
2006
The aim of this study was to compare respiratory gas exchange variables and muscle fatigue between equal-intensity (i.e., same force output) electrostimulated and voluntary contractions of the quadriceps muscle (46+/-10% of maximal voluntary force). Twelve healthy men served as volunteers. Oxygen consumption, ventilation and respiratory exchange ratio were recorded during the exercise bouts. Muscle fatigue was quantified as the exercise-induced reduction in maximal voluntary force. The average oxygen consumption (11+/-3 versus 8+/-2 mL min(-1)kg(-1)), ventilation (23+/-4 versus 16+/-2 L min(-1)) and respiratory exchange ratio (0.96+/-0.02 versus 0.85+/-0.01) were significantly higher during…
Ventilatory chemosensitivity, cerebral and muscle oxygenation, and total hemoglobin mass before and after a 72-day mt. Everest expedition.
2014
Abstract. Cheung, Stephen S, Niina E. Mutanen, Heikki M. Karinen, Anne S. Koponen, Heikki Kyro ̈ la ̈ inen, Heikki O. Tikkanen, and Juha E. Peltonen. Ventilatory chemosensitivity, cerebral and muscle oxygenation, and total hemoglobin mass before and after a 72-day Mt. Everest expedition. High Alt Med Biol 15:331–340, 2014.— Background: We investigated the effects of chronic hypobaric hypoxic acclimatization, performed over the course of a 72-day self-supported Everest expedition, on ventilatory chemosensitivity, arterial saturation, and tissue oxygenation adaptation along with total hemoglobin mass (tHb-mass) in nine experienced climbers (age 37 – 6 years, _ VO 2peak 55 – 7mL $ kg - 1 $ min…
Muscle ultrasonography and computed tomography in elderly trained and untrained women
1993
Ultrasonography (US) and computed tomography (CT) were compared in studying the associations between long-term physical training and quadriceps muscle mass and structure in female athletes and controls, aged 66-85 years. Muscle cross-sectional area (CSA) measured using US correlated highly with that measured using CT, but the latter technique yielded 30% higher values on average. The echo intensity of the fasciae and bone measured by US correlated positively with the mean radiological density and negatively with the relative proportion of fat obtained from CT. Low intramuscular echo intensity was accompanied by high muscle density and low relative proportion of fat. The athletes had larger …
Knee extension strength and walking speed in relation to quadriceps muscle composition and training in elderly women.
1994
Summary. Knee extension strength, walking speed, quadriceps muscle mass and composition of the muscle compartment were studied in 66 to 85-year-old female athletes and controls. Maximal voluntary knee extension force, force/body mass, extension torque, torque/body mass and walking speed were higher for the athletes than the controls. A muscle index indicating intramuscular fat and connective tissue measured using ultrasonography was lower for the athletes than the controls. There were no differences between the study groups in knee extension force related either to cross-sectional area (CSA) or lean tissue area (CSAL) of the quadriceps. Within the subgroups, there was no significant correla…
Die dynamische 31-Phosphor-Magnetresonanz-Spektroskopie des M. quadriceps: Einfluß von Geschlecht und Alter auf spektroskopische Parameter
1999
PURPOSE 31P-MRS is used to assess the influence of sex und age on quadriceps muscle metabolism before and after exercise. MATERIALS AND METHODS 32 healthy volunteers (15 women, 17 men, mean age: 38 +/- 17 yrs.) were examined by dynamic phosphorus-31 (31P) magnetic resonance spectroscopy (MRS). In the magnet, the quadriceps muscle was stressed by an isometric und an isotonic form of exercise until exhaustion, respectively. RESULTS Resting conditions: With increasing subjects' age, the ratio beta-adenosine triphosphate/total phosphate decreased (r = -0.37; p = 0.02). With increasing subjects' age, the ratios inorganic phosphate/phosphocreatine (r = 0.79; p = 5 x 10(-8), phosphomonoester/beta-…
Effects of motor imagery on strength, range of motion, physical function, and pain intensity in patients with total knee arthroplasty: A systematic r…
2021
Abstract Background In the early stages of total knee arthroplasty (TKA) rehabilitation, in which physical function in general can be affected, motor imagery (MI) might play a relevant role. Objective To assess the impact of MI on strength, active range of motion (ROM), pain intensity, and physical function in patients with TKA. Methods We conducted a systematic review and meta-analysis of randomised controlled trials. Pooled effects were calculated as standardised mean differences (SMDs) and 95% confidence intervals (CIs) for the relevant outcomes using random effects model. The certainty of evidence was assessed with GRADE approach. Results This review included 7 articles. The addition of…
Twitch interpolation during equal-intensity voluntary and electrically-evoked isometric contractions of the quadriceps muscle
2005
It has been suggested that, during contractions triggered by electrical stimulation, motor units are recruited in a reversed sequence compared to voluntary contraction. The classic view is that lar...
Knee extensor and flexor muscle power explains stair ascension time in patients with unilateral late-stage knee osteoarthritis: a cross-sectional stu…
2014
To determine the extent of asymmetrical deficits in knee extensor and flexor muscles, and to examine whether asymmetrical muscle deficits are associated with mobility limitations in persons with late-stage knee osteoarthritis (OA).Cross-sectional.Research laboratory.A clinical sample (N=56; age range, 50-75y) of eligible persons with late-stage knee OA awaiting knee replacement.Not applicable.Knee extensor and flexor power and torque assessed isokinetically; thigh muscle cross-sectional area (CSA) assessed by computed tomography; mobility limitation assessed by walking speed and stair ascension time; and pain assessed with the Western Ontario and McMaster Universities Osteoarthritis Index q…
Velocity-based resistance training: do women need greater velocity loss to maximize adaptations?
2021
Abstract Purpose Men and women typically display different neuromuscular characteristics, force–velocity relationships, and differing strength deficit (upper vs. lower body). Thus, it is not clear how previous recommendations for training with velocity-loss resistance training based on data in men will apply to women. This study examined the inter-sex differences in neuromuscular adaptations using 20% and 40% velocity-loss protocols in back squat and bench press exercises. Methods The present study employed an 8-week intervention (2 × week) comparing 20% vs. 40% velocity-loss resistance training in the back squat and bench press exercises in young men and women (~ 26 years). Maximum strengt…