Search results for "Isometric exercise"
showing 10 items of 449 documents
The cross-sectional area of the gluteus maximus muscle varies according to habitual exercise loading: Implications for activity-related and evolution…
2015
Greater size of the gluteus maximus muscle in humans compared to non-human primates has been considered an indication of its function in bipedal posture and gait, especially running capabilities. Our aim was to find out how the size of the gluteus maximus muscle varies according to sports while controlling for variation in muscle strength and body weight. Data on gluteus maximus muscle cross-sectional area (MCA) were acquired from magnetic resonance images of the hip region of female athletes (N=91), and physically active controls (N=20). Dynamic muscle force was measured as counter movement jump and isometric knee extension force as leg press. Five exercise loading groups were created: hig…
Effects of strength vs. endurance training and their combination on physical performance characteristics in female horseback riders
2020
BACKGROUND: The purpose of this study was to investigate effects of strength (S), endurance (E) and concurrent strength and endurance (SE) training on neuromuscular and cardiorespiratory characteristics during the 12-week volume-equated protocols in female horseback riders. METHODS: Subjects (N=44) (29.4±8.9 yrs) were assigned to S (n=11), E (n=11), SE (n=13) and control (C) (n=9) groups. Training consisted of progressive S, E or SE training 3x/week and riding exercise 4-6x/week. The measurements included maximal isometric bilateral leg press force (MVCLP) and EMG of VL and BF muscles, rapid isometric force production (0-500ms), maximal force of trunk extensor/flexors (MVCE/MVCF), countermo…
Deadlift muscle force and activation under stable and unstable conditions.
2010
The objective of this study was to compare the production of force and paraspinal muscle activity between deadlifts carried out in a standard way and with different instability devices (Bosu and T-Bow). Deadlifts involve the performance of muscle activities with dynamic and isometric characteristics. Thirty-one subjects participated voluntarily in the study. Initially, they performed an isometric test for 5 seconds in each condition. After that, they performed a set of 5 repetitions with 70% of the maximum isometric force obtained in each one of the previously evaluated conditions. During the isometric tests, records of electromyographic activity and force production were obtained, whereas …
Endogenous Hormones, Muscle Strength, and Risk of Fall-Related Fractures in Older Women
2006
Background. Among older people, fracture-causing fall often leads to health deterioration. The role of endogenous hormone status and muscle strength on fall-related fracture risk is unclear. This study investigates if, after adjustment for bone density, endogenous hormones and muscle strength would predict fall-related limb fracture incidence in older community-dwelling women followed-up over 10 years. Methods. As a part of a prospective population-based study, 187 75-year-old women were investigated. Serum estradiol, testosterone, sex hormone binding globulin, and dehydroepiandrosterone sulfate concentrations were analyzed, and isometric muscle strength and bone mineral density were assess…
Effects of strength and endurance training on isometric muscle strength and walking speed in elderly women
1996
The separate effects of 18 weeks of intensive strength and endurance training on isometric knee extension (KE) and flexion (KF) strength and walking speed were studied in 76- to 78- year-old women. Maximal voluntary isometric force for both KE and KF was measured in a sitting position on a custom-made dynamometer chair at a knee angle of 60 degrees from full extension. Maximal walking speed was measured over a distance of 10 m. The endurance-trained women increased KE torque and KE torque/body mass after the first 9 weeks of training when compared with the controls. when comparing the baseline, 9 week and 18 week measurements within the groups separately, both the endurance- and strength-tr…
Intramuscular sex steroid hormones are associated with skeletal muscle strength and power in women with different hormonal status
2015
International audience; Estrogen (E2)-responsive peripheral tissues, such as skeletal muscle, may suffer from hormone deficiency after menopause potentially contributing to the aging of muscle. However, recently E2 was shown to be synthesized by muscle and its systemic and intramuscular hormone levels are unequal. The objective of the study was to examine the association between intramuscular steroid hormones and muscle characteristics in premenopausal women (n = 8) and in postmenopausal monozygotic twin sister pairs (n = 16 co-twins from eight pairs) discordant for the use of E2-based hormone replacement. Isometric skeletal muscle strength was assessed by measuring knee extension strength.…
Velocity-specific training in elbow flexors.
1999
The purpose of this study was to show that velocity-specific training may be implicated in modifications in the level of coactivation of agonist and antagonist muscles. Healthy males (n = 20) were randomly placed in to two groups: one group trained using concentric contractions (n = 12), the other was an untrained control group (n = 8). The training group underwent unilateral resistance training at a level of 35 (5)% of a one-repetition maximal contraction of the elbow flexors, executed at maximal angular velocity. Training sessions consisted of six sets of eight consecutive elbow flexions, three times per weak for a total of seven weeks. The velocity of the ballistic movements executed dur…
Changes in agonist-antagonist EMG, muscle CSA, and force during strength training in middle-aged and older people
1998
Effects of 6 mo of heavy-resistance training combined with explosive exercises on neural activation of the agonist and antagonist leg extensors, muscle cross-sectional area (CSA) of the quadriceps femoris, as well as maximal and explosive strength were examined in 10 middle-aged men (M40; 42 ± 2 yr), 11 middle-aged women (W40; 39 ± 3 yr), 11 elderly men (M70; 72 ± 3 yr) and 10 elderly women (W70; 67 ± 3 yr). Maximal and explosive strength remained unaltered during a 1-mo control period with no strength training. After the 6 mo of training, maximal isometric and dynamic leg-extension strength increased by 36 ± 4 and 22 ± 2% ( P < 0.001) in M40, by 36 ± 3 and 21 ± 3% ( P < 0.001) in M7…
Antagonist mechanical contribution to resultant maximal torque at the ankle joint in young and older men.
2007
Abstract A recorded muscular torque at one joint is a resultant torque corresponding to the participation of both agonist and antagonist muscles. This study aimed to examine the effect of aging on the mechanical contributions of both plantar- and dorsi-flexors to the resultant maximal voluntary contraction (MVC) torques exerted at the ankle joint, in dorsi-flexion (DF) and plantar-flexion (PF). The estimation of isometric agonist and antagonist torques by means of an EMG biofeedback technique was made with nine young (mean age 24 years) and nine older (mean age 80 years) men. While there was a non-significant age-related decline in the measured resultant DF MVC torque (−15%; p =0.06), there…
How the ankle joint angle alters the antagonist and agonist torques during maximal efforts in dorsi- and plantar flexion
2011
The aim of this study was to assess, via an EMG bio-feedback method, the ankle joint angle effect on the agonist and antagonist torques in plantar- (PF) and dorsi-flexion (DF). The isometric PF and DF maximal voluntary contractions (MVCs) torques were measured simultaneously with surface EMG activity of triceps surae (TS) and tibialis anterior (TA) muscles in 12 young adults (mean age 27) at five different ankle joint angles. Our results showed that: (i) The coactivation level does not properly reflect the mechanical effect of the antagonist muscle, (ii) TS antagonist torque significantly altered the DF MVC-angle relationship, whereas TA antagonist torque did not influence this MVC-angle re…