A5090801711- Muscle activation and electromyography studies
- Sports Performance and Training
- Sports injuries and prevention
- Muscle Physiology and Disorders
- Motor Control and Adaptation
- Cardiovascular and exercise physiology
- Exercise and Physiological Responses
- Fluid Dynamics and Turbulent Flows
- Transcranial Magnetic Stimulation Studies
- Neuroscience and Neural Engineering
- Cardiomyopathy and Myosin Studies
- Heart Rate Variability and Autonomic Control
- Adipose Tissue and Metabolism
- Muscle metabolism and nutrition
- Advanced Sensor and Energy Harvesting Materials
- Gas Dynamics and Kinetic Theory
- Cerebral Palsy and Movement Disorders
- Mathematics and Applications
- Knee injuries and reconstruction techniques
- Computational Fluid Dynamics and Aerodynamics
- Experimental and Theoretical Physics Studies
- Advanced Mathematical Modeling in Engineering
- High voltage insulation and dielectric phenomena
- Stroke Rehabilitation and Recovery
- Balance, Gait, and Falls Prevention
University of Guelph
2016-2025
University of Calgary
2013-2016
Western University
2009-2015
University of Oregon
2015
Université du Québec à Montréal
2015
McGill University
2015
Memorial University of Newfoundland
2009-2011
Darlington Memorial Hospital
1991
Hartford Financial Services (United States)
1991
University of Nottingham
1957-1969
A contributing factor to the loss of muscle mass and strength during aging is reduction in number functioning motor units (MU). It has been shown that lifelong physically active older rats have greater numbers MU compared with age-matched sedentary controls, suggesting chronic exercise may preserve function advancing age. This not previously examined humans.Thus, purpose this study was estimate tibialis anterior masters runners (approximately 65 yr) compare values recreationally young 25...
A contributing factor to the loss of muscle mass and strength with adult aging is reduction in number functioning motor units (MUs). Recently, we reported that lifelong competitive runners (master = ∼66 yr) had greater numbers MUs a leg (tibialis anterior) than age-matched recreationally active controls. This suggested long-term exposure high levels physical activity may limit MU aging. However, it unknown if this finding result activation specifically exercised motoneuron pool (i.e.,...
A complementary pair of extremum principles are proved for a Newtonian viscous fluid in quasi-static flow. It is shown how these can be used to obtain arbitrarily close approximations from above and below the total rate energy dissipation hence drag on translated or rotated body fluid.
Our group has shown a greater number of functioning motor units (MU) in cohort highly active older (∼65 yr) masters runners relative to age-matched controls. Because the precipitous loss MUs eighth and ninth decades life it is unknown whether world class octogenarian athletes (MA) would also have numbers compared with We measured MU neuromuscular transmission stability tibialis anterior champion MAs (∼80 values healthy controls yr). Decomposition-enhanced spike-triggered averaging was used...
The stretch-shortening cycle (SSC) occurs in most everyday movements, and is thought to provoke a performance enhancement of the musculoskeletal system. However, mechanisms this remain matter debate. One proposed mechanism associated with stretch-induced increase steady-state force, referred as residual force (RFE). As yet, direct evidence relating RFE increased force/work during SSCs missing. Therefore, forces electrically stimulated m. adductor pollicis (n = 14 subjects) were measured...
It is unclear during human aging whether healthy older adults (>70 yr old) experience greater, lesser, or the same fatigability compared with younger adults. The reported disparate findings may be related to task-dependent nature of fatigue and limited number studies exploring nonisometric contractile function aging. purpose here was determine effects fast shortening contractions on triceps surae in 10 young (~24 old (~78 men using isometric dynamic measures. Participants performed 50...
Normal adult aging is associated with impaired muscle contractile function; however, to what extent cross-bridge kinetics are altered in not clear. We used a slacken restretch maneuver on single fiber segments biopsied from the vastus lateralis of young adults (∼23 yr), older nonathlete (NA) (∼80 and age-matched world class masters athletes (MA; ∼80 yr) assess rate force redevelopment (ktr) kinetics. A post hoc analysis was performed, only mechanical properties "slow type" fibers based...
In older adults, isometric force production is enhanced following a voluntary lengthening contraction when compared with produced at the same muscle length without prior contraction. This phenomenon termed residual enhancement (RFE), and appears to be related age-related maintenance of eccentric (ECC) strength. However, it unknown whether changes in architecture contribute greater RFE short long lengths old age. Neuromuscular properties knee extensors were assessed on HUMAC NORM dynamometer....
This study investigated the effects of acute and chronic beetroot juice (BRJ) supplementation on submaximal exercise oxygen uptake (VO2), time trial (TT) performance, contractile properties plantar flexors in females. Study 1: Using a double blind, randomized, crossover design, 12 recreationally active females using hormonal contraceptives supplemented acutely (2.5 h) chronically (8 days) with 280 mL BRJ/d (~26 mmoles nitrate []) or -free placebo (PLA). On days 1 8, participants cycled for...
This study aimed to investigate the effects of blood flow restriction (BFR) combined with electrical muscle stimulation (EMS) on skeletal mass and strength during a period limb disuse.Thirty healthy participants (22 ± 3 yr; 23 kg·m-2) were randomly assigned control (CON; n = 10), BFR alone (BFR; or EMS (BFR + EMS; 10). All completed unloading single leg for 14 d, no treatment (CON), while treated either (twice daily, 5 d·wk-1). involved arterial three cycles 5-min occlusion using...
The loss of sarcomeres in series with age contributes to declining muscle performance. present study investigated whether eccentric training could improve performance via serial sarcomere addition old muscle, like young muscle. Four weeks maximal induced the rat plantar flexors and improved vivo performance, however, led dysfunctional remodeling accompanied by further impaired rats.
Despite an age-related loss of voluntary isometric and concentric strength, muscle strength is well maintained during lengthening actions (i.e., eccentric strength) in old age. Additionally, younger adults activated skeletal muscle, the force level observed following stretch greater than at same length. This feature termed residual enhancement (RFE) believed to be a combination active passive components contractile apparatus. The purpose this study was provide initial assessment RFE older...
We evaluated the effects of differential muscle architectural adaptations on neuromuscular fatigue resistance. Seven young males and six females participated in this study. Using a longitudinal within-subject design, legs were randomly assigned to perform isometric training tibialis anterior (TA) three times per week for 8 wk at short (S-group) or long muscle-tendon unit length (L-group). Before following training, fascicle (FL) pennation angle (PA) TA assessed. As well, fatigue-related time...
Abstract The abrupt cessation of ovarian hormone release is associated with declines in muscle contractile function, yet the impact gradual failure on contractility across peri‐, early‐ and late‐stage menopause remains unclear. In this study, a 4‐vinylcyclohexene diepoxide (VCD)‐induced mouse model was used to examine time course changes mechanical function. Plantar flexors female mice (VCD: n = 10; CON: 8) were assessed at 40 (early perimenopause), 80 (late 120 (menopause onset) 176...
Introduction: Aging is associated with a reduction in muscle fascicle length (FL), which contributes to sarcopenia: the age-related loss of mass and function. Studies on rodents have confirmed this reduced FL driven by sarcomeres aligned series (serial sarcomere number; SSN) along muscle. However, studies focused primarily rat plantar flexor SSN at two aging timepoints, leaving an incomplete view changes SSN. Hence, study investigated as contributor five hindlimb muscles across four...
Abstract The age-related loss of muscle mass is partly driven by a reduction in serial sarcomere number (SSN), and further SSN occurs during immobilization. associated with optimal force power production passive tension, thus immobilization-induced especially concern for older individuals who are often subjected to forced disuse illness injury. We previously showed that submaximal eccentric resistance training increased improved function old rats. present study investigated whether this...