scholarly journals Age and Sex Effects on the Active Stiffness of Vastus Intermedius under Isometric Contraction

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Cong-Zhi Wang ◽  
Jing-Yi Guo ◽  
Tian-Jie Li ◽  
Yongjin Zhou ◽  
Wenxiu Shi ◽  
...  
Keyword(s):  
Knee Joint ◽  
Isometric Contraction ◽  
Maximum Voluntary Contraction ◽  
The Elderly ◽  
Voluntary Contraction ◽  
Muscle Stiffness ◽  
Elderly Subjects ◽  
Vastus Intermedius ◽  
Significant Difference ◽  
Age And Sex

Previously, a novel technique was proposed to quantify the relationship between the muscle stiffness and its nonfatigue contraction intensity. The method extended the measured range of isometric contraction to 100% maximum voluntary contraction (MVC) using an ultrasonic shear wave measurement setup. Yet, it has not been revealed how this relationship could be affected by factors like age or sex. To clarify these questions, vastus intermedius (VI) stiffness of 40 healthy subjects was assessed under 11 step levels of isometric contraction. The subjects were divided into four groups: young males, young females, elderly males, and elderly females (n=10for each). In a relaxed state, no significant difference was observed between the male and female subjects (p=0.156) nor between the young and elderly subjects (p=0.221). However, when performing isometric contraction, the VI stiffness of males was found to be significantly higher than that of females at the same level (p<0.001), and that of the young was higher than the elderly (p<0.001). Meanwhile, for two knee joint angles used, the stiffness measured at a 90° knee joint angle was always significantly larger than that measured at 60° (p<0.001). Recognizing the active muscle stiffness of VI contributes to body stability, and these results may provide insight into the age and sex bias in musculoskeletal studies, such as those on fall risks.

Training-related enhancement in the control of motor output in elderly humans

1994 ◽  
Vol 77 (6) ◽  
pp. 2648-2658 ◽  
Author(s):  
D. A. Keen ◽  
G. H. Yue ◽  
R. M. Enoka
Keyword(s):  
Training Program ◽  
Motor Unit ◽  
Maximum Voluntary Contraction ◽  
The Elderly ◽  
Voluntary Contraction ◽  
Elderly Subjects ◽  
Contraction Force ◽  
Unit Force ◽  
Young And Elderly Subjects ◽  
Elderly Humans

The increase in motor unit force that occurs with aging has been hypothesized to cause a decline in the ability to maintain a constant submaximal force. To test this hypothesis, young and elderly subjects performed a 12-wk strength-training program that was intended to increase motor unit force. The training program caused similar increases (%initial) in the training load (137.4 +/- 17.2%), twitch force (23.1 +/- 7.4%), and maximum voluntary contraction force (39.2 +/- 6.8%) of the first dorsal interosseus muscle for the young and elderly subjects. The increase in strength was associated with a modest increase in muscle volume (7% of initial value) and a nonmonotonic increase in the surface-recorded electromyogram that was significant at week 8 but not at week 12. The elderly subjects reduced the variability in force at the lower target forces (2.5, 5.0, and 20.0% maximum voluntary contraction force). This improvement, however, was unrelated to changes in the distribution of motor unit forces, which was not consistent with the hypothesis that the greater coefficient of variation for the force fluctuations is due to increased motor unit forces.

Older adults can maximally activate the biceps brachii muscle by voluntary command

1998 ◽  
Vol 84 (1) ◽  
pp. 284-291 ◽  
Author(s):  
Sophie J. De Serres ◽  
Roger M. Enoka
Keyword(s):  
Older Adults ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Maximum Voluntary Contraction ◽  
The Elderly ◽  
Voluntary Contraction ◽  
Elderly Subjects ◽  
Biceps Brachii Muscle ◽  
Activation Level ◽  
Voluntary Command

De Serres, Sophie J., and Roger M. Enoka. Older adults can maximally activate the biceps brachii muscle by voluntary command. J. Appl. Physiol. 84(1): 284–291, 1998.—Because some of the decline in strength with age may be explained by an impairment of muscle activation, the purpose of this study was to determine the activation level achieved in biceps brachii by older adults during a maximum voluntary contraction (MVC). This capability was assessed with two superimposition techniques: one calculated the activation level that was achieved during an MVC, and the other provided an estimate of the expected MVC force based on extrapolation with submaximal forces. The activation level in biceps brachii was incomplete (<100%) for the young ( n = 16) and elderly ( n = 16) subjects, with the elderly subjects exhibiting the greater deficit. In contrast, there was no difference between the measured and expected MVC forces for either group of subjects, whether the extrapolation involved a third-order polynomial or linearization of the data. Because of the lower signal-to-noise ratio associated with the measurement of activation level and the greater number of measurements that contributed to the estimate of the expected MVC force, we conclude that the older adults were able to achieve complete activation of the biceps brachii muscle during an MVC.

scholarly journals POS1288 TUBERCULOUS SPONDYLODISCITIS IN ELDERLY: EPIDEMIOLOGY, CLINICAL, FEATURES, TREATMENT AND OUTCOMES

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 926.1-926
Author(s):  
M. Mrabet ◽  
S. Boussaid ◽  
S. Jemmali ◽  
H. Sahli ◽  
H. Ajlani ◽  
...  
Keyword(s):  
Clinical Features ◽  
The Elderly ◽  
Lumbar Pain ◽  
Elderly Subjects ◽  
Normocytic Anemia ◽  
Imaging Features ◽  
X Rays ◽  
Significant Difference ◽  
Young Subjects ◽  
Tuberculous Spondylodiscitis

Background:Tuberculosis is still endemic all over the world. The incidence of tuberculous spondylodiscitis (TS) is steadily increasing. Clinical features and outcomes of this affection are various and depending on various parameters, including age.Objectives:Our objective was to explore the differences in presentation and the results of further investigations and the prognosis of TS between young and elderly subjects.Methods:We conduct a retrospective and descriptive study in a single rheumatology department. Data were collected from files of patients hospitalized in the past 20 years (2000-2020) who have been diagnosed with TS. We carried out a comparative study concerning the clinical biological, imaging features and outcomes between young subjects and subjects aged over 65 years.Results:Fifty-two cases of TS were collected (37F/15M). The mean age of the population was 55.21 years ± 17.79 [19-91]. Thirty-three patients (69.2%) were classified as young versus 16 elderly patients (30.8%), with female predominance in both groups (69.4% and 75% respectively, p = 0.57). Young subjects was more frequently vaccinated (88.9%) by Bacillus Calmette–Guérin (BCG) (p < 0.001). A delayed diagnosis was noted in both groups (p = 0.24). Lumbar spine involvement was the most common (57.7%). In the two age ranges, the onset of the disease was progressive (p = 0.22), characterized by segmental spine stiffness (p = 0.57) and lumbar pain with general signs (p = 0.27), such as: impaired general condition, fever, night sweats and weight loss. Biological inflammatory syndrome and normochrome normocytic anemia were encountered in both cases (p = 0.08 and p = 0.2, respectively). Standard X-rays and Computed tomography were more performed in young subjects (94.4% and 69.4%, respectively; p < 0.001), unlike magnetic resonance imaging which was more common in elderly subjects but with no statistically significant difference (p = 0.22). Disc pinch, erosion of vertebral plateaus and vertebral collapse were the major signs (82.7%, 65.4% and 67.3%, respectively). Clinical, biological and imaging arguments contributed to positive diagnosis in both groups (p = 0.24). Common medical treatment was anti-tuberculosis: Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), Ethambutol (E) and physical treatment such as immobilization witch was more common in the eldery (56.3%, p = 0.16). The evolution of the disease was characterized by a clear improvement of young subjects during the second week of treatment (p < 0.001). A more frequent clinical improvement in older subjects was during the fourth week but with no statistically significant difference (p = 0.13). The occurrence of immediate complications was more frequent in the elderly (p = 0.23) with a predominance for drug complications (56.3%) such as: hepatic cytolysis (12.5%), hyperuricemia (18.8%) and major intolerance to anti-tuberculosis (18.8%).Conclusion:TS is a frequent condition that needs to be treated rapidly. the clinical presentation of TS in the elderly is less noisy which leads to more frequent complications and mortality.Disclosure of Interests:None declared

Decreased Neutrophil Cyclic AMP Response to Isoprenaline Stimulation in the Elderly

1983 ◽  
Vol 65 (2) ◽  
pp. 155-157 ◽  
Author(s):  
T. G. Cotter ◽  
K. O'Malley
Keyword(s):  
Monoclonal Antibodies ◽  
Cyclic Amp ◽  
The Elderly ◽  
Population Heterogeneity ◽  
Elderly Subjects ◽  
Age Related ◽  
Significant Difference ◽  
Young Subjects ◽  
Drug Free

1. Neutrophils from drug-free elderly subjects produced approximately 50% less cyclic AMP in response to isoprenaline than did neutrophils from young subjects. A significant difference in basal cyclic AMP levels was also evident (elderly 2.8 ± 0.37; young 4.9 ± 0.36 pmol of cAMP/107 cells; P < 0.05). 2. With a range of anti-neutrophil monoclonal antibodies no evidence of age-related neutrophil population heterogeneity was found. 3. These findings indicate that the age-related decline in β-adrenoceptor responsiveness is not due to changes in the neutrophil population. 4. The present results support the hypothesis that there is a generalized decline in β-adrenoceptor-mediated responsiveness in the elderly.

Changes of muscular sound during sustained isometric contraction up to exhaustion

1989 ◽  
Vol 66 (4) ◽  
pp. 1593-1598 ◽  
Author(s):  
C. Orizio ◽  
R. Perini ◽  
A. Veicsteinas
Keyword(s):  
Isometric Contraction ◽  
Exercise Intensity ◽  
Maximum Voluntary Contraction ◽  
Isometric Exercise ◽  
Surface Emg ◽  
Voluntary Contraction ◽  
Biceps Muscle ◽  
Output Force ◽  
Contact Transducer ◽  
Four Levels

The sound (SMG) generated by the biceps muscle during isometric exercise at 20, 40, 60, and 80% of maximum voluntary contraction (MVC) up to exhaustion has been recorded by a contact transducer and integrated (iSMG), together with the surface electromyogram (EMG) in eight young untrained men. At the onset of exercise, iSMG and integrated surface EMG (iEMG) amplitude increased linearly with exercise. iSMG remained constant for 253 +/- 73 (SD), 45 +/- 16, 21 +/- 5, and 0 s at the four levels of contraction. Then iSMG increased linearly at 20% MVC, fluctuated at 40% MVC, and decreased exponentially at 60 and 80% MVC. iSMG exhaustion-to-onset ratio was 5.0 at 20%, 1.0 at 40%, and 0.2 at 60 and 80% MVC. On the contrary, independently of exercise intensity, iEMG increased with time, being 1.4 higher at exhaustion than at the onset. The nonunivocal iSMG changes with time and effort of exercise suggest that the sound may be a useful tool to acquire different information to EMG and output force during muscle contraction up to fatigue.

scholarly journals Description of suicide ideation among older adults and a psychological profile: a cross-sectional study in Turkey

2019 ◽  
Vol 24 (5) ◽  
pp. 1865-1874 ◽  
Author(s):  
Murat Aslan ◽  
Cicek Hocaoglu ◽  
Bulent Bahceci
Keyword(s):  
Suicidal Ideation ◽  
Suicide Ideation ◽  
Psychiatric Morbidity ◽  
Depression Scale ◽  
The Elderly ◽  
Elderly Subjects ◽  
Reasons For Living ◽  
Low Level ◽  
Significant Difference ◽  
The Mean

Abstract This study investigates the suicidal ideation and the possible causes for suicidal behaviour in the elderly. Subjects were 150 patients aged 65 and older who were evaluated using the sociodemographic data collection forms, Geriatric Depression Scale (GDS), Suicidal Ideation Scale (SIS), Reasons for Living Inventory (RLI), and Beck Hopelessness Scale (BHS). Of 150 patients, 72.7% were women and 27.3% were men, ages ranged from 65 to 88 years. Suicidal ideation was noted in 30.7% of patients. When the mean of BHS total score between patients with and without suicidal ideation and the mean of BHS subscale’s feelings and expectations regarding the future and loss of motivation and hope in terms of subscales were evaluated between the groups with and without suicidal ideation, the scores had a significant difference. When RLI was evaluated in terms of total scores, the suicidal ideation mean score was 243.74 ± 32.28, while the non-suicidal ideation mean score was 267.27 ± 24.36. There was a significant relationship between the two groups. We found low level of education, low level of reasons for living and higher psychiatric morbidity (generalized anxiety disorder and comorbid depressive disorder) in with suicidal ideation in the elderly.

scholarly journals Maximum Voluntary Activation in Nonfatigued and Fatigued Muscle of Young and Elderly Individuals

2001 ◽  
Vol 81 (5) ◽  
pp. 1102-1109 ◽  
Author(s):  
Scott K Stackhouse ◽  
Jennifer E Stevens ◽  
Samuel CK Lee ◽  
Karen M Pearce ◽  
Lynn Snyder-Mackler ◽  
...  
Keyword(s):  
Maximum Voluntary Contraction ◽  
Quadriceps Femoris ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Elderly Subjects ◽  
Central Activation ◽  
Quadriceps Femoris Muscle ◽  
Age Related ◽  
Young Subjects ◽  
Femoris Muscle

Abstract Background and Purpose. Researchers studying central activation of muscles in elderly subjects (≥65 years of age) have investigated activation in only the nonfatigued state. This study examined the ability of young and elderly people to activate their quadriceps femoris muscles voluntarily under both fatigued and nonfatigued conditions to determine the effect of central activation failure on age-related loss of force. Subjects and Methods. Twenty young subjects (11 men, 9 women; mean age=22.67 years, SD=4.14, range=18–32 years) and 17 elderly subjects (8 men, 9 women; mean age=71.5 years, SD=5.85, range=65–84 years) participated in this study. Subjects were seated on a dynamometer and stabilized. Central activation was quantified, based on the change in force produced by a 100-Hz, 12-pulse electrical train that was delivered during a 3- to 5-second isometric maximum voluntary contraction (MVC) of the quadriceps femoris muscle. Next, subjects performed 25 MVCs (a 5-second contraction with 2 seconds of rest) to fatigue the muscle. During the last MVC, central activation was measured again. Results. In the nonfatigued state, elderly subjects had lower central activation than younger subjects. In the fatigued state, this difference became larger. Discussion and Conclusion. Central activation of the quadriceps femoris muscle in elderly subjects was reduced in both the fatigued and nonfatigued states when compared with young subjects. Some part of age-related weakness, therefore, may be attributed to failure of central activation in both the fatigued and nonfatigued states.

Maintenance of Uncued Isometric Contractions by Blind and Sighted

1979 ◽  
Vol 49 (2) ◽  
pp. 475-479
Author(s):  
Claudia G. Emes
Keyword(s):  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Isometric Contractions ◽  
Hand Grip ◽  
Significant Difference ◽  
Static Contractions

A comparison of 10 blind and 10 sighted subjects to a proprioceptive task was examined by analysis of response to maintenance of uncued static contractions. In attempting to sustain hand-grip tensions at specified percentages of maximum voluntary contraction, blind and sighted groups showed no significant difference in performance.

Development of a Walking-Assistance Apparatus for Neuro-Rehabilitation

2012 ◽  
Vol 162 ◽  
pp. 258-265 ◽  
Author(s):  
Eiichirou Tanaka ◽  
Tadaaki Ikehara ◽  
Tomohiro Sakurai ◽  
Takahiro Suzuki ◽  
Shota Roppongi ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Maximum Voluntary Contraction ◽  
Pressure Sensors ◽  
The Elderly ◽  
Thenar Eminence ◽  
Voluntary Contraction ◽  
Hip Joints ◽  
Walking Behavior ◽  
Leg Alignment ◽  
Soles Of The Feet

We have developed a prototype for a walking-assistance apparatus that serves as a next-generation vehicle or a movable neuro-rehabilitation training appliance for the elderly or motor palsy patients. Our prototype uses a novel spatial parallel link mechanism with a weight-bearing lift. Flat steps of the apparatus move in parallel with the ground; the apparatus supports the entire leg alignment (including soles of the feet) and assists walking behavior at the ankle, knee, and hip joints simultaneously. To estimate the walking phase of each leg of the equipped person, pressure sensors were attached under the thenar eminence and the heel of the sole and the pressure variation at each sensing point was measured. To determine the direction in which the equipped person is walking, a pressure sensor was attached to the flexible crural link. Motor palsy patients and those with muscle weakness can walk with the assistance of the apparatus. Patients who have ambulation difficulty can also use the apparatus with a weight-bearing lift that we developed. Using the apparatus with the weight-bearing lift prevents stumbling and enables input of walking movement to the brain motor area. The validity of the weight-bearing lift can be confirmed from the results of the measured %maximum voluntary contraction (MVC).

scholarly journals Crossfit Practice: An Electromyographic Analysis of Masticatory Muscles

2020 ◽  
Author(s):  
Nayara Soares da Silva ◽  
Marcelo Palinkas ◽  
Evandro Marianetti Fioco ◽  
Edson Donizetti Verri ◽  
Saulo César Vallin Fabrin ◽  
...  
Keyword(s):  
Maximum Voluntary Contraction ◽  
Masticatory Muscles ◽  
Voluntary Contraction ◽  
Control Group ◽  
Electromyographic Activity ◽  
Physical Conditioning ◽  
Striated Muscles ◽  
Functional Changes ◽  
Significant Difference ◽  
The Impact

Abstract Background: CrossFit is a regular high-intensity physical conditioning exercise for skeletal striated muscles, which promotes functional changes in the human body. The aim of this study was to investigate the impact of CrossFit exercise on the electromyographic activity of the masseter and temporalis muscles. Methods: Forty participants were divided into two groups: athletes who practiced CrossFit (n=20) and controls who did not practice sports (n=20). The electromyographic activities of the masseter and temporalis muscles were measured using mandibular tasks at rest, protrusion, right laterality, left laterality, and dental clenching in maximum voluntary contraction and habitual chewing of peanuts and raisins. Both the groups were matched for age, sex, and body mass index. The data were analyzed using the t-test with a 5% significance level. Results: Reduced electromyographic activities were found in all mandibular tasks in the CrossFit group than in the control group, with a significant difference for the right masseter (p=0.01), left masseter (p=0.001), and left temporal muscles (p=0.001) at mandibular rest; right (p=0.001) and left (p=0.001) masseter in chewing of peanuts. Conclusion: The results of this study suggest that CrossFit promotes positive changes in electromyographic activity of the masticatory muscles, especially in the mandibular rest and chewing of hard food. CrossFit exercise practiced within the appropriate technical protocols improves masticatory muscle function.

Sign in / Sign up

Export Citation Format

Share Document