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The purpose of this investigation was to describe the relationship between the central activation ratio (CAR) and the percent maximum voluntary effort (% MVE) during isometric quadriceps femoris contractions. Twenty-one healthy, young adults participated in three test sessions. During each session, one of three train types was tested: a 100-HZ 120-ms train,(More)
STUDY OBJECTIVE To evaluate the safety, tolerability, and pharmacokinetic profile of fosphenytoin, a water-soluble phenytoin prodrug, after intramuscular and intravenous administration. DESIGN Open-label study of intramuscular administration, and double-blind, randomized study of intravenous administration. SETTING Six and ten hospitals throughout the(More)
Potentiation is the enhancement of force seen after repetitive activation of skeletal muscle. The frequency and duration of stimulation, total number of pulses delivered to the muscle, and the peak forces or force-time integrals produced by the stimulation all have been suggested to affect the degree of potentiation. The purpose of this study was to(More)
The molecular phylogeny of the gobioid fishes, comprising 33 genera and 43 valid species, was examined by use of complete mitochondrial 12S rRNA and tRNA(VAL)genes. Both parsimony and neighbor-joining analyses revealed comparable results and are generally congruent with those of morphological studies. The Odontobutis, which was always placed at the base of(More)
Stability is an important concern during human walking and can limit mobility in clinical populations. Mediolateral stability can be efficiently controlled through appropriate foot placement, although the underlying neuromechanical strategy is unclear. We hypothesized that humans control mediolateral foot placement through swing leg muscle activity, basing(More)
Neuromuscular electrical stimulation can generate contractions through peripheral and central mechanisms. Direct activation of motor axons (peripheral mechanism) recruits motor units in an unnatural order, with fatigable muscle fibers often activated early in contractions. The activation of sensory axons can produce contractions through a central mechanism,(More)
Neuromuscular electrical stimulation (NMES) is commonly used in clinical settings to activate skeletal muscle in an effort to mimic voluntary contractions and enhance the rehabilitation of human skeletal muscles. It is also used as a tool in research to assess muscle performance and/or neuromuscular activation levels. However, there are fundamental(More)
We tested how lateral stability affects gait as a function of age. A simple computational model suggests that walking is laterally unstable and that age-related decreases in motor and sensory function may be treated as noise-like perturbations to the body. Step width variability may be affected by active control of foot placement subject to noise. We(More)
The passive dynamics of bipedal limbs alone are sufficient to produce a walking motion, without need for control. Humans augment these dynamics with muscles, actively coordinated to produce stable and economical walking. Present robots using passive dynamics walk much slower, perhaps because they lack elastic muscles that couple the joints. Elastic(More)
BACKGROUND We quantified age-related decreases in the ability of female participants to generate whole leg movements about the hip. METHODS We measured maximum hip strength and hip velocity in 12 young and 12 older healthy women. Both capabilities could help fall prevention by contributing to fast leg movements. We also measured maximum velocities as a(More)