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1. The objectives of this study were to (1) quantify experimentally in vivo changes in pennation angle, fibre length and muscle thickness in the triceps surae complex in man in response to changes in ankle position and isometric plantarflexion moment and (2) compare changes in the above muscle architectural characteristics occurring in the transition from(More)
1. The purpose of the present study was to examine the effect of a plantarflexor maximum voluntary contraction (MVC) on Achilles tendon moment arm length. 2. Sagittal magnetic resonance (MR) images of the right ankle were taken in six subjects both at rest and during a plantarflexor MVC in the supine position at a knee angle of 90 deg and at ankle angles of(More)
In this study, we estimated the specific tensions of soleus (Sol) and tibialis anterior (TA) muscles in six men. Joint moments were measured during maximum voluntary contraction (MVC) and during electrical stimulation. Moment arm lengths and muscle volumes were measured using magnetic resonance imaging, and pennation angles and fascicular lengths were(More)
1. The effects of single isovelocity shortening contractions on force production of the electrically stimulated human adductor pollicis muscle were investigated in seven healthy male subjects. 2. Redeveloped isometric force immediately following isovelocity shortening was always depressed compared with the isometric force recorded at the same muscle length(More)
Neuromuscular function and fatigue have been studied using a wide variety of preparations. These range from sections of single fibers from which the cell membrane has been removed to whole muscles or groups of muscles acting about a joint in the intact animal. Each type of preparation has its merits and limitations. There is no ideal preparation; rather the(More)
Selected contractile properties and fatigability of the quadriceps muscle were studied in seven spinal cord-injured (SCI) and 13 able-bodied control (control) individuals. The SCI muscles demonstrated faster rates of contraction and relaxation than did control muscles and extremely large force oscillation amplitudes in the 10-Hz signal (65 +/- 22% in SCI(More)
A spinal cord injury usually leads to an increase in contractile speed and fatigability of the paralysed quadriceps muscles, which is probably due to an increased expression of fast myosin heavy chain (MHC) isoforms and reduced oxidative capacity. Sometimes, however, fatigue resistance is maintained in these muscles and also contractile speed is slower than(More)
The aim of the present study was to estimate and compare in vivo measurement-based Achilles tendon moment arm lengths at rest and during isometric plantarflexion maximum voluntary contraction (MVC) using the centre-of-rotation (COR) and the tendon-excursion (TE) methods. Both methods were based on morphometric analysis of sagittal-plane magnetic resonance(More)
STUDY DESIGN A longitudinal training study. OBJECTIVES To assess if contractile speed and fatigability of paralysed quadriceps muscles in individuals with spinal cord injury (SCI) can be altered by functional electrical stimulation leg cycle ergometry (FES-LCE) training. SETTINGS The Sint Maartenskliniek rehabilitation centre and the University of(More)
Voluntary activation levels during lengthening, isometric, and shortening contractions (angular velocity 60 degrees/s) were investigated by using electrical stimulation of the femoral nerve (triplet, 300 Hz) superimposed on maximal efforts. Recruitment of fiber populations was investigated by using the phosphocreatine-to-creatine ratio (PCr/Cr) of single(More)