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991.
Madeleine P Jørgensen LV Søgaard K Arendt-Nielsen L Sjøgaard G 《European journal of applied physiology》2002,87(1):28-37
The goal of the present study was to investigate the significance of low-force continuous or intermittent static contraction
and feedback mode (visual or proprioceptive) on the development of muscle fatigue as assessed by electromyography (EMG) and
mechanomyography (MMG). Visual (force control) and proprioceptive (displacement control) feedback was investigated during
intermittent (6 s contraction, 4 s rest) and continuous static contractions at 10% and 30% of the maximum voluntary contraction
(MVC). Mean force, force fluctuation, rating of perceived exertion and root mean square (RMS) and mean power frequency (MPF)
of the EMG and MMG signals were analysed. The general pattern for MMG RMS and EMG RMS values and the rating of perceived exertion
was an increase with contraction time, while the EMG MPF values decreased (P<0.05). The increase in RMS values was generally more pronounced for the MMG compared with the EMG, while the decrease in
MPF values was more consistent for the EMG compared with the MMG signal. During the intermittent contractions, the main effect
was on MPF for both EMG and MMG. Lower force fluctuation and larger rating of perceived exertion (P<0.05), greater slopes of EMG and MMG RMS and MPF values versus time were observed with proprioceptive feedback compared with
visual feedback. The findings suggest that (1) the EMG and MMG signals give complementary information about localised muscle
fatigue at low-level contraction: they responded differently in terms of changes in the time and frequency domain during continuous
contraction, while they responded in concert in the frequency domain during intermittent contractions, and (2) the different
centrally mediated motor control strategies used during fatiguing contraction may be dependent upon the feedback modality.
Electronic Publication 相似文献
992.
993.
Mary E. Jones Madeleine A.M. Davies Kirsten M. Leyland Antonella Delmestri Angus Porter Jason Ratcliffe Nick Peirce Julia L. Newton Nigel K. Arden 《Journal of Science and Medicine in Sport》2018,21(6):558-563
Objectives
This study aimed to describe the prevalence and risk of chronic conditions in former elite cricketers compared to a normal population, and describe wellbeing in former elite cricketers.Design
Cross-sectional study.Methods
Former elite cricketers, recruited from the Professional Cricketers’ Association, completed a self-report cross-sectional questionnaire. The English Longitudinal Study of Ageing (ELSA) served as the normal population. The prevalence of self-reported, GP-diagnosed conditions (heart problems, hypertension, stroke, diabetes, asthma, dementia, osteoarthritis (OA), total hip replacement (THR), total knee replacement (TKR), anxiety, depression) were reported for both population samples. Standardised morbidity ratios (SMRs) compared chronic conditions in sex-, age- and BMI-matched former cricketers (n = 113) and normal population (n = 4496).Results
Heart problems were reported by 13.3% of former cricketers, significantly lower than the normal population, SMR 0.55 (0.33–0.91). Former cricketers reported 31.9% hypertension, 1.8% stroke, 6.2% diabetes, 15.0% asthma, and no dementia, none significantly different to the normal population. OA, THR, and TKR were reported by 51.3%, 14.7% and 10.7% of former cricketers, respectively, significantly higher than the normal population, SMRs 3.64 (2.81–4.71), 3.99 (2.21–7.20) and 3.84 (1.92–7.68). Anxiety and depression were reported by 12.4% and 8.8% of former cricketers, respectively, SMRs 3.95 (2.34–6.67) and 2.22 (1.20–4.14). 97% of former cricketers reflected they would undertake their cricket career again, 98% agreed that cricket enriched their lives.Conclusions
Heart problems were significantly lower, while OA, THR, TKR, anxiety, and depression were significantly higher in the former cricketers compared to the normal population (ELSA). Most former cricketers reflected positively on their career. 相似文献994.
The effects of experimentally induced pain in tibialis anterior on step initiation were studied in six healthy male volunteers by kinematics, kinetics and electromyography (EMG). We observed longer reaction times, lower joint moments and decreased EMG activity in the painful leading leg’s tibialis anterior and gastrocnemius muscles. Peripheral nociceptive input appeared to alter the internal representation used in the step initiation motor program. 相似文献
995.
996.
Laminin {alpha}1 chain corrects male infertility caused by absence of laminin {alpha}2 chain
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Häger M Gawlik K Nyström A Sasaki T Durbeej M 《The American journal of pathology》2005,167(3):823-833
Laminins are important for basement membrane structure and function. The laminin alpha2 chain is a major component of muscle basement membranes, and mutations in the laminin alpha2 gene lead to congenital muscular dystrophy in humans and mice. Although the laminin alpha2 chain is prominently expressed in testicular basement membranes, its role in testis has remained unclear. Here, we show that laminin alpha1, alpha2, beta1, beta2, gamma 1, and gamma 3 chains are the major laminin chains in basement membranes of seminiferous tubules. In laminin alpha2 chain-deficient dy(3 K)/dy(3 ASK) mice, lack of laminin alpha2 chain led to concurrent reduction of laminin gamma 3 chain and abnormal testicular basement membranes. Seminiferous tubules of laminin alpha2 chain-deficient dy(3 K)/dy(3 K) mice displayed a defect in the timing of lumen formation, resulting in production of fewer spermatides. We also demonstrate that overexpression of laminin alpha1 chain in testis of dy(3 K)/dy(3 K) mice compensated for laminin alpha2 chain deficiency and significantly reversed the appearance of the histopathological features. We thus provide genetic data that laminin alpha chains are essential for normal testicular function in vivo. 相似文献
997.
Volker Adams Werner Kempf Shabbir Hassam Jakob Briner Mirka Schmid Rita Moos Madeleine Pfaltz 《Journal of medical virology》1995,46(3):189-193
Epidemiological studies indicate that acquired immunodeficiency syndrome (AIDS)-associated Kaposi's sarcoma (KS) may be caused by an infectious, preferentially sexually transmitted agent. Infections with human papilloma viruses are common, sexually transmitted diseases occurring frequently in homosexual men, who are also the main risk group of developing KS. In order to evaluate the possible role of HPV in the development of KS, 24 cutaneous AIDS-associated Kaposi's sarcomas were investigated by the polymerase chain reaction (PCR) and by in situ hybridization for the presence of human papilloma viruses (HPV). HPV DNA sequences were detected in 5 of 24 KS specimens, in 4 of 13 normal skin specimens from AIDS patients withoutKS and in 5 of 14 skin specimens of HIV-seronegative patients. For the first time, HPV types 6 and 33 were detected by PCR in KS. A higher proportion of HPV types 16/18 was found in AIDS-associated KS specimens, whereas HPV type 33 was seen more often in normal skin specimens of the control group. Apart from the known HPV types 16/18 described in KS, this study demonstrates also the presence of HPV 6 and 33 in this condition. © 1995 Wiley-Liss, Inc. 相似文献
998.
999.
Nielsen Lene Kongsgaard King Madeleine Möller Sören Jarden Mary Andersen Christen Lykkegaard Frederiksen Henrik Gregersen Henrik Klostergaard Anja Steffensen Morten Saaby Pedersen Per Trøllund Hinge Maja Frederiksen Mikael Jensen Bo Amdi Helleberg Carsten Mylin Anne Kærsgaard Abildgaard Niels 《Quality of life research》2020,29(2):335-346
Quality of Life Research - The quality of patient-reported outcome (PRO) data can be compromised by non-response (NR) to scheduled questionnaires, particularly if reasons for NR are related to... 相似文献
1000.