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BACKGROUND Previous investigators have reported that maximal power increases during growth and decreases with aging. These age-related differences have been reported to persist even when power is scaled to body mass or muscle size. We hypothesized that age-related differences in maximal power were primarily related to differences in muscle size and(More)
During repetitive contractions, muscular work has been shown to exhibit complex relationships with muscle strain length, cycle frequency, and muscle shortening velocity. Those complex relationships make it difficult to predict muscular performance for any specific set of movement parameters. We hypothesized that the relationship of impulse with cyclic(More)
The purpose of this investigation was to determine whether selectively blocking D1 and D2 dopamine receptors produces a differential effect on the characteristics (speed and success) of the reaction time response in rats. Animals were shaped to release a lever in response to an auditory/visual stimulus to avoid mild foot shock. The selective D1 antagonist(More)
The SRT, DRT, and MT of older men (OA) who have experienced a life style of chronic physical activity were compared to those of nonactive men of similar age (ONA), and also to active (YA) and nonactive young men (YNA). Although activity level and age were significant factors, most of the activity level-by-age interaction in all but DRT was attributed to the(More)
Thirty male Sprague-Dawley rats 100 days of age were divided into three groups: interval trained, endurance trained, and pair-weighted controls. Both trained groups ran up to one hour per day, 6 days per week for 12 weeks. The interval trained group ran up to 20 repeat intervals at 54 meters per minute for 30 seconds, while the endurance trained group ran(More)
The purpose of this investigation was to determine the effects of cycle crank length on maximum cycling power, optimal pedaling rate, and optimal pedal speed, and to determine the optimal crank length to leg length ratio for maximal power production. Trained cyclists (n=16) performed maximal inertial load cycle ergometry using crank lengths of 120, 145,(More)
Isometric impulse frequencies associated with active tremor and force regulation were examined in 10 patients with idiopathic Parkinson's disease (PD) and in 10 older adults (OAs) who performed an isometric tracing task. The authors decoupled and analyzed the data to determine whether PD-related tremor in the thumb and in the index finger during isometric(More)
Thirty-two Long Evans male rats with sham operations or unilateral 6-OHDA-induced damage to meso-telencephalic dopaminergic neurons were evaluated on a reactive capacity task that demanded high speed movement initiation. The task required lever manipulation to avoid signalled shock. The interval between the warning and the shock was incrementally reduced. A(More)