Effects of long-term exercise on volumetric bone mineral density (vBMD), bone mineral content, bone geometric properties, and the strength indexes of bone were examined in a cross-sectional study of athletes and controls. Tibias of 25 jumpers (13 women), 30 swimmers (15 women), and 25 controls (15 women), aged 18-23 yr, were scanned at midsite by using peripheral quantitative computed tomograph...

This is the first report of the psychobiology of stress in BASE jumpers, one of the most dangerous forms of extreme sport. We tested the hypotheses that indicators of emotional style (temperament) predict salivary cortisol reactivity, whereas indicators of intentional goal-setting (persistence and character) predict salivary alpha-amylase reactivity during BASE jumping. Ninety-eight subjects co...

Sensation seeking (SS) traits may drive individuals toward high-intensity environments because of a desire for novelty and risk; however, research has not identified the psychophysiological mechanisms underlying SS behavioral expression or disentangled the relative contribution of novelty-seeking for physiological arousal. We used an ambulatory device to measure autonomic nervous system (ANS) a...

Every scientist’s nightmare is betting everything on an experiment that will take unheard-of investment and well over a decade to complete — only to have a Johnny-come-lately stride in midway through the work and declare that he’s going to beat you to the finish by years. The ‘J.’ in J. Craig Venter may not stand for ‘Johnny’, but the rest of the bad dream is happening to Francis Collins and th...

To characterize the electromyographic (EMG) activity, ground reaction forces, and kinematics were used in the running jump with different takeoff angles. Two male long jumpers volunteered to perform running jumps at different approach speeds by varying the number of steps (from 3 to 9) in the run-up. Subject TM achieved a greater vertical velocity of the center of gravity (CG) at takeoff for al...

High jumpers run at moderate speeds and set down the foot, from which they take off, well in front of the body. Long jumpers run up much faster and place the foot less far forward, with the leg at a steeper angle. A simple model, which takes into account the mechanical properties of muscle, predicts optimum take-off techniques that agree well with those used by athletes. These predictions are r...