Search results for "liha"
showing 10 items of 620 documents
Assessment of maximal handgrip strength: How many attempts are needed?
2017
BACKGROUND: Handgrip strength (HGS) is used to identify individuals with low muscle strength (dynapenia). The influence of the number of attempts on maximal HGS is not yet known and may differ depending on age and health status. This study aimed to assess how many attempts of HGS are required to obtain maximal HGS.METHODS: Three cohorts (939 individuals) differing in age and health status were included. HGS was assessed three times and explored as continuous and dichotomous variable. Paired t-test, intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to test reproducibility of HGS. The number of individuals with misclassified dynapenia at attempts 1 and 2 with respe…
The effect of ageing and physical activity level on muscle fatigue during isometric contraction of knee extensor muscles
2013
Nahar, Nazmun 2013. Effect of ageing and physical activity level on muscle fatigue during isometric contraction of knee extensor muscles. Master’s theses in Biomechanics. Department of Biology of Physical Activity, University of Jyväskylä, Finland. Muscle fatigue is defined as the loss of force or power producing capacity in response to contractile activity and is a fundamental characteristic of skeletal muscle. The aim of this study was to identify whether time to failure remains same or increases in elderly people compared with young people. Another aim was to identify time to failure is same or less in active old people compared with inactive old people. One hundred and ten subjects were…
Power training and postmenopausal hormone therapy affect transcriptional control of specific co-regulated gene clusters in skeletal muscle
2010
At the moment, there is no clear molecular explanation for the steeper decline in muscle performance after menopause or the mechanisms of counteractive treatments. The goal of this genome-wide study was to identify the genes and gene clusters through which power training (PT) comprising jumping activities or estrogen containing hormone replacement therapy (HRT) may affect skeletal muscle properties after menopause. We used musculus vastus lateralis samples from early stage postmenopausal (50–57 years old) women participating in a yearlong randomized double-blind placebo-controlled trial with PT and HRT interventions. Using microarray platform with over 24,000 probes, we identified 665 diffe…
Muscular transcriptome in postmenopausal women with or without hormone replacement.
2007
The loss of muscle mass and strength with aging is well characterized, but our knowledge of the molecular mechanisms underlying the development of sarcopenia remains incomplete. Although menopause is often accompanied with first signs of age-associated changes in muscle structure and function, the effects of hormone replacement therapy (HRT) or menopause-related decline in estrogen production in the muscles of postmenopausal women is not well understood. Furthermore the knowledge of the global transcriptional changes that take place in skeletal muscle in relation to estrogen status has thus far been completely lacking. We used a randomized double-blinded study design together with an explor…
Ankle and knee extensor muscle effort during locomotion in young and older athletes : Implications for understanding age-related locomotor decline
2019
AbstractAge-related reduction in muscle force generation capacity is similarly evident across different lower limb muscle groups, yet decline in locomotor performance with age has been shown to depend primarily on reduced ankle extensor muscle function. To better understand why ageing has the largest detrimental effect on ankle joint function during locomotion, we examined maximal ankle and knee extensor force development during a two-leg hopping test in older and young men, and used these forces as a reference to calculate relative operating efforts for the knee and ankle extensors as participants walked, ran and sprinted. We found that, across locomotion modes in both age groups, ankle ex…
Sprint and Strength Training Modulates Autophagy and Proteostasis in Aging Sprinters
2020
Purpose Exercise and aging may modulate muscle protein homeostasis and autophagy, but few studies examine highly-trained middle-aged or older individuals. This study elucidated the effects of a new long-term training stimulus on markers of muscle autophagy and unfolded protein response (UPR) and on sprint running performance in masters sprinters. Methods Thirty-two male competitive sprinters (aged 40–76 years) were randomly divided into experimental (EX) and control (CTRL) groups. The EX training program was a combination of heavy and explosive strength and sprint exercises aimed at improving sprint performance. Fifteen and thirteen participants completed the 20-week intervention period in …
Design and validation of a wireless Body Sensor Network for integrated EEG and HD-sEMG acquisitions
2022
Sensorimotor integration is the process through which the human brain plans the motor program execution according to external sources. Within this context, corticomuscular and corticokinematic coherence analyses are common methods to investigate the mechanism underlying the central control of muscle activation. This requires the synchronous acquisition of several physiological signals, including EEG and sEMG. Nevertheless, physical constraints of the current, mostly wired, technologies limit their application in dynamic and naturalistic contexts. In fact, although many efforts were made in the development of biomedical instrumentation for EEG and High Density-surface EMG (HD-sEMG) signal ac…
Acute Metabolic Response, Energy Expenditure, and EMG Activity in Sitting and Standing
2017
Purpose While merely standing up interrupts sedentary behavior, it is important to study acute metabolic responses during single bouts of sitting and standing to understand the physiological processes affecting the health of office workers. Methods Eighteen healthy middle-age women 49.4 ± 7.9 yr old (range: 40–64) with a body mass index of 23.4 ± 2.8 kg·m−2 volunteered for this laboratory-based randomized crossover trial where they performed 2 h desk work in either sitting or standing postures after overnight fasting. Muscle activity (normalized to walking at 5 km·h−1), respiratory gas exchange, and blood samples were assessed after glucose loading (75 g). Results Compared with seated work,…
The impact of maternal weight in pregnancy on glucose metabolism in non-diabetic offspring in late adulthood
2019
Aims: We aimed to examine the association between maternal adiposity and glucose metabolism in adult offspring without diabetes, simultaneous taking offspring own adiposity into account. Methods: This longitudinal birth cohort study (Helsinki Birth Cohort Study) included 1,440 non-diabetic subjects examined at a mean age of 62 years. Subjects were divided into quartiles according to maternal body mass index (BMI). The impact of maternal BMI on offspring body composition was also studied. Results: There were no differences in fasting glucose between the groups. In men, maternal BMI was inversely associated with mean 2-hour glucose concentration after a 75 g oral glucose tolerance test (p <0.…
5(4H)-Oksazolonu iegūšana no cisteīna
2018
5(4H)-Oksazolona iegūšana no cisteīna. Štrāla S., zinātniskais vadītājs Dr. ķīm., doc. Kļimenkovs I. Kursa darbs organiskajā ķīmijā, 39 lappuses, 10 attēli, 5 tabulas, 32 literatūras avoti, 4 pielikumi. Latviešu valodā. Darbā ir apkopota informācija par cisteīna īpašībām, cisteīna aizsarggrupām, oksazolonu sintēzi un īpašībām, kā arī par oksazolonu Štegliha pārgrupēšanos. Eksperimentālajā daļā ir veikta vairāku cisteīna atvasinājumu sintēze, ko var izmantot tālākās reakcijās oksazolonu iegūšanai.