ORCID Profile
0000-0002-6191-045X
Current Organisation
Sheffield Hallam University
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Publisher: Springer Science and Business Media LLC
Date: 05-06-2017
DOI: 10.1007/S00198-017-4104-2
Abstract: Bone mineral density declines with increasing older age. We examined the levels of circulating factors known to regulate bone metabolism in healthy young and older adults. The circulating levels of dickkopf-1, osteocalcin, osteoprotegerin and sclerostin were positively associated with whole-body bone mineral density (WBMD) in older adults, despite the average WBMD being lower and circulating dickkopf-1, osteoprotegerin and sclerostin being higher in old than young. This study aims to investigate the relationship between whole-body bone mineral density (WBMD) and levels of circulating factors with known roles in bone remodelling during 'healthy' ageing. WBMD and fasting plasma concentrations of dickkopf-1, fibroblast growth factor-23, osteocalcin, osteoprotegerin, osteopontin and sclerostin were measured in 272 older subjects (69 to 81 years 52% female) and 171 younger subjects (18-30 years 53% female). WBMD was lower in old than young. Circulating osteocalcin was lower in old compared with young, while dickkopf-1, osteoprotegerin and sclerostin were higher in old compared with young. These circulating factors were each positively associated with WBMD in the older adults and the relationships remained after adjustment for covariates (r values ranging from 0.174 to 0.254, all p < 0.01). In multivariate regression, the body mass index, circulating sclerostin and whole-body lean mass together accounted for 13.8% of the variation with WBMD in the older adults. In young adults, dickkopf-1 and body mass index together accounted for 7.7% of variation in WBMD. Circulating levels of dickkopf-1, osteocalcin, osteoprotegerin and sclerostin are positively associated with WBMD in community-dwelling older adults, despite the average WBMD being lower and circulating dickkopf-1, osteoprotegerin and sclerostin being higher in old than young.
Publisher: Wiley
Date: 16-03-2017
DOI: 10.1113/EP086190
Publisher: American Physiological Society
Date: 06-2016
DOI: 10.1152/JAPPLPHYSIOL.00091.2016
Abstract: Training specificity is considered important for strength training, although the functional and underpinning physiological adaptations to different types of training, including brief explosive contractions, are poorly understood. This study compared the effects of 12 wk of explosive-contraction (ECT, n = 13) vs. sustained-contraction (SCT, n = 16) strength training vs. control ( n = 14) on the functional, neural, hypertrophic, and intrinsic contractile characteristics of healthy young men. Training involved 40 isometric knee extension repetitions (3 times/wk): contracting as fast and hard as possible for ∼1 s (ECT) or gradually increasing to 75% of maximum voluntary torque (MVT) before holding for 3 s (SCT). Torque and electromyography during maximum and explosive contractions, torque during evoked octet contractions, and total quadriceps muscle volume (QUADS VOL ) were quantified pre and post training. MVT increased more after SCT than ECT [23 vs. 17% effect size (ES) = 0.69], with similar increases in neural drive, but greater QUADS VOL changes after SCT (8.1 vs. 2.6% ES = 0.74). ECT improved explosive torque at all time points (17–34% 0.54 ≤ ES ≤ 0.76) because of increased neural drive (17–28%), whereas only late-phase explosive torque (150 ms, 12% ES = 1.48) and corresponding neural drive (18%) increased after SCT. Changes in evoked torque indicated slowing of the contractile properties of the muscle-tendon unit after both training interventions. These results showed training-specific functional changes that appeared to be due to distinct neural and hypertrophic adaptations. ECT produced a wider range of functional adaptations than SCT, and given the lesser demands of ECT, this type of training provides a highly efficient means of increasing function.
Publisher: Springer Science and Business Media LLC
Date: 30-07-2014
Publisher: Springer Science and Business Media LLC
Date: 31-05-2013
DOI: 10.1007/S10522-013-9434-7
Abstract: Within the European multi-centre MyoAge project, one workpackage was designed to investigate the contribution of age-related changes to muscle mass, contractile characteristics and neural control in relation to reductions in mobility in older age. The methodology has been described here. Test centres were located in Manchester, UK Paris, France Leiden, The Netherlands Tartu, Estonia and Jyväskylä, Finland. In total, 182 young (18-30 years old, 52.2 % female) and 322 older adults (69-81 years old, 50 % female) have been examined. The participants were independent living, socially active and free from disease that impaired mobility levels. The older participants were selected based on physical activity levels, such that half exceeded current recommended physical activity levels and the other half had lower physical activity levels than is recommended to maintain health. Measurements consisted of blood pressure anthropometry and body composition (dual-energy X-ray absorptiometry and magnetic resonance imaging) lung function standing balance and cognitive function (CANTAB). Mobility was assessed using the Timed Up and Go, a 6 min walk, activity questionnaires and accelerometers to monitor habitual daily activities. Muscle strength, power, fatigue and neural activation were assessed using a combination of voluntary and electrically stimulated contractions. Fasting blood s les and skeletal muscle biopsies were collected for detailed examination of cell and molecular differences between young and older in iduals. The results from this study will provide a detailed insight into "normal, healthy" ageing, linking whole-body function to the structure and function of the neuromuscular system and the molecular characteristics of skeletal muscle.
Publisher: Frontiers Media SA
Date: 04-09-2018
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Thomas Maden-Wilkinson.