To determine whether aerobic fitness training alters response to psychosocial stress, 38 males were randomly assigned to either aerobic, anaerobic (weight-lifting), or waiting-list control groups. Experimental groups met three to four times per week in 1-hr sessions aimed at improving either cardiovascular endurance or muscular strength. Aerobic fitness level, heart rate and subjective response to laboratory psychosocial stress, and self-reports of daily stress, coping resources and psychologic symptoms were assessed prior to and following 10 weeks of training. Although posttraining fitness measures confirmed the effectiveness of aerobic training, no group differences were seen on laboratory or self-report measures. However, for aerobic trainers alone, fitness improvement tended to correlate with faster heart rate recovery following psychosocial stress. Fitness improvement was not correlated with any other psychologic changes. This experiment provides only modest support for the hypothesis that aerobic training alters response to psychosocial stress. It is suggested that future work on the psychologic effects of aerobic fitness explore the contribution of training parameters as well as subject characteristics.

Acceleration, or an increase in the rate of movement, is integral to success in many sports. Improvements in acceleration often entail workouts done at intensities that elicit higher blood lactate concentrations (BLa). The purpose of the study is to assess the impact of acceleration on BLa. Methods required subjects (n = 45) to perform 4 workouts that each involved two 1-minute sets of hip- and knee-extension repetitions on an inertial exercise trainer (Impulse Training Systems, Newnan, Georgia). Subjects performed 2 workouts comprised solely of phasic or tonic repetitions; their sequence was randomized to prevent an order effect. Before and 5 minutes after exercise, subjects' BLa were assessed with a calibrated analyzer (Sports Resource Group, Hawthorne, New York). Post and delta (post-pre) BLa both served as criterion measures for multivariate analysis. Average and peak acceleration values, derived from both phasic and tonic workouts, served as predictor variables. Results showed statistical significance (p < 0.05; R = 0.2534) and yielded the following prediction equation from phasic workouts: delta BLa = 1.40 + 1.116 (average acceleration set 1)--0.011 (peak acceleration set 1)--0.634 (average acceleration set 2) + 0.005 (peak acceleration set 2). Conclusions suggest delta BLa variance, which represents the increase of the metabolite incurred from workouts, is most easily explained by average acceleration values, which describes the mean increase in the rate of movement from phasic workouts. To improve an athlete's tolerance for acceleration-induced BLa increases, workouts should be tailored with respect to the muscles involved and the duration of exercise bouts of their chosen sport.