Search results for "Exercise"
showing 10 items of 3151 documents
Alterations of Neuromuscular Function After Prolonged Running, Cycling and Skiing Exercises
2004
It is well known that impairment of performance resulting from muscle fatigue differs according to the types of contraction involved, the muscular groups tested and the exercise duration/intensity. Depending on these variables, strength loss with fatigue can originate from several sites from the motor cortex through to contractile elements. This has been termed 'task dependency of muscle fatigue'. Only recently have studies focused on the origin of muscle fatigue after prolonged exercise lasting 30 minutes to several hours. Central fatigue has been shown to contribute to muscle fatigue during long-distance running by using different methods such as the twitch interpolation technique, the ra…
Selective muscle hypertrophy, changes in EMG and force, and serum hormones during strength training in older women.
2001
Effects of strength training (ST) for 21 wk were examined in 10 older women (64 ± 3 yr). Electromyogram, maximal isometric force, one-repetition maximum strength, and rate of force development of the leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris (QF) and of vastus lateralis (VL), medialis (VM), intermedius (VI) and rectus femoris (RF) throughout the lengths of 3/12–12/15 (Lf) of the femur, muscle fiber proportion and areas of types I, IIa, and IIb of the VL were evaluated. Serum hormone concentrations of testosterone, growth hormone (GH), cortisol, and IGF-I were analyzed for the resting, preexercise, and postexercise conditions. After the 21-wk ST, maximal for…
Shared Genetic and Environmental Effects on Strength and Power in Older Female Twins
2005
Purpose: This study examined the relative contribution of genetic and environmental effects on maximal leg extensor power and also investigated whether leg extensor power and maximum voluntary isometric knee extensor strength share a genetic component. Methods: Muscle functions were measured as part of the Finnish Twin Study on Aging in 101 monozygotic (MZ) and 116 dizygotic (DZ) female twin pairs aged 63–76 yr. Leg extensor power was measured using the Nottingham Leg Extensor Power Rig and maximum voluntary isometric knee extensor strength using an adjustable dynamometer chair. The analyses were carried out using the maximum likelihood method in Mx-program on the raw data set. Results: A b…
Inspiratory and Lower-Limb Strength Importance in Mountain Ultramarathon Running. Sex Differences and Relationship with Performance
2020
The study was aimed at comparing lower-limb strength and respiratory parameters between male and female athletes and their interaction with performance in a 107 km mountain ultramarathon. Forty seven runners (29 males and 18 females
Mindful Exercise (Baduanjin) as an Adjuvant Treatment for Older Adults (60 Years Old and Over) of Knee Osteoarthritis: A Randomized Controlled Trial
2020
Background. The postural stability is a major factor that helps prevent developing knee osteoarthritis with aging. The aim of this study was to investigate the effects of Baduanjin qigong on postural control and physical function in older adults with knee osteoarthritis. Methods. Fifty-six individuals over 60 years of age with knee osteoarthritis were randomly assigned to either an experimental group (n = 28) or a control group (n = 28). Participants in the experimental group received a 12-week Baduanjin training, while those in the control group did not receive any additional physical exercise during the study period. The postural control was quantified by perimeter and ellipse area of cen…
Comparing Active, Passive, and Combined Warm-Ups Among Junior Alpine Skiers in −7°C
2020
Context: Warming up in very cold climates and maintaining an elevated body temperature prior to a race is challenging for snow-sport athletes. Purpose: To investigate the effects of active (ACT), passive (PAS), and a combination of ACT and PAS (COM) warm-ups on maximal physical performance in a subzero environment among snow-sport athletes. Methods: Ten junior alpine skiers completed 3 experimental trials in −7.2 (0.2)°C. The ACT involved 5 minutes of moderate cycling, 3 × 15-second accelerations, a 6-second sprint, 5 countermovement jumps (CMJs), and a 10-minute passive transition phase, while in PAS, participants wore a lower-body heated garment for 24 minutes. In COM, participants comple…
Effects of strength and endurance training on thigh and leg muscle mass and composition in elderly women
1995
The effects of 18 wk of intensive strength and endurance training on knee extensor, knee flexor, and lower leg muscle mass and composition were studied in 76- to 78-yr-old women. Muscle cross-sectional area (CSA), lean tissue CSA, and relative proportion of fat were determined using computed tomography. The strength-trained women increased their total muscle lean tissue CSA of the thigh (1.5%; P = 0.035), quadriceps CSA (4.5%; P = 0.021), quadriceps lean tissue CSA (5.8%, P = 0.009), and mean Hounsfield unit of the lower leg muscles (11.2%; P = 0.035) compared with the changes that occurred in the control group during the experiment. The change in quadriceps lean tissue CSA because of the …
Leucine supplementation and intensive training.
1999
Leucine, isoleucine and valine, the branched-chain amino acids (BCAA), make up about one-third of muscle protein. Of these, leucine has been the most thoroughly investigated because its oxidation rate is higher than that of isoleucine or valine. Leucine also stimulates protein synthesis in muscle and is closely associated with the release of gluconeogenic precursors, such as alanine, from muscle. Significant decreases in plasma or serum levels of leucine occur following aerobic (11 to 33%), anaerobic lactic (5 to 8%) and strength exercise (30%) sessions. In skeletal muscle, there is a decrease in leucine level and a reduction in glycogen stores during exhaustive aerobic exercise. Basal fast…
Quantitative ultrasonography of muscle: Detection of adaptations to training in elderly women
1996
Abstract Objective: To develop quantitative ultrasonography in studying the adaptation of quadriceps muscle mass and composition to short-term physical training and rehabilitation in elderly women. Design: Randomized control trial. Setting: Measurements in a research laboratory and training in a fitness center and sports hall. Participants: Forty-two women, aged 76 to 78 years, with no indications against intensive physical exercise, randomly assigned to strength ( n = 16), endurance ( n = 15), and control ( n = 11) groups. Twelve subjects from the strength, 12 from the endurance, and 11 from the control group completed the study. Intervention: Supervised physical training 3 times a week fo…
Effects of Strength Training on Muscle Strength Characteristics, Functional Capabilities, and Balance in Middle-Aged and Older Women
2006
Progressive strength training can lead to substantial increases in maximal strength and mass of trained muscles, even in older women and men, but little information is available about the effects of strength training on functional capabilities and balance. Thus, the effects of 21 weeks of heavy resistance training--including lower loads performed with high movement velocities--twice a week on isometric maximal force (ISOmax) and force-time curve (force produced in 500 milliseconds, F0-500) and dynamic 1 repetition maximum (1RM) strength of the leg extensors, 10-m walking time (10WALK) and dynamic balance test (DYN.D) were investigated in 26 middle-aged (MI; 52.8 +/- 2.4 years) and 22 older …