This study examined the effects of acute dehydration on repeated bouts of anaerobic cycling exercise. Eight college wrestlers performed 2 cycle ergometer trials before (hydrated, H) and 48 hrs after dehydration (D) via exercise, fluid restriction, and heat exposure. The trials consisted of a 4 min warm-up followed by 5, 10 s maximal bouts interspersed with 20 s rest intervals. The ergometer was preloaded with .1 kg/kg of H bodyweight. Peak power (PP,W), average power (AP,W), time to peak power (TTPP,s), power fatigue rate (PFR,W/s), and power fatigue index (PFI,%) were recorded by an integrated microcomputer. Pretrial plasma osmolality (PO), HTC, plasma electrolytes, and caloric intake (Kcal) were also measured. The wrestlers lost 4.5±1.0% (X±SD) bodyweight from H to D trials which increased PO and HTC (p<.01). There was a decline in plasma [K+] (p<.05) and no change in Kcal. PP values for H bouts 1-5 were 1004±54, 918±47, 809446, 727438, and 681±40 and for D bouts 1-5 were 937±52, 836±46, 766±40, 702±41, and 706±32 (X±SEM). AP results were similar to PP and thus not shown. There were no differences in H and D trials for TTPP, PFR, and PFI. After dehydration PP and AP were reduced during bouts 1-3 (p<.05) and appear to level in bouts 4 and 5 coinciding with H PP and AP. These results suggest that rapid dehydration by wrestlers causes a decrease in PP and AP production during initial bouts of repeated anaerobic exercise. With the onset of fatigue in later bouts PP and AP are unaffected. / Master of Science

This investigation evaluated the cardiorespiratory responses to three rider positions while undergoing maximal cycle ergometry. The positions were determined by the position of the hands on the handlebars and the posture of the upper body: upright (UP), and drop position (DP) with conventional racing handlebars, and an aerodynamic tuck (AT) using Scott DH time-trial handlebars. Ten well-trained (mean V02max=60.7 ± 3.63 ml*kg-1*min-1) cyclists underwent three randomly assigned separate maximal ergometry tests using each position. Variables of interest were: heart rate (RR), systolic blood pressure (SBP), diastolic blood pressure (DBP) , rate pressure product (RPP) , oxygen consumption (V02), pulmonary ventilation (VI)' ventilatory equivalent (V1/V02), respiratory exchange ratio (RER), ratings of perceived exertion (RPE) , and total time to test termination (TT). These variables did not differ significantly between rider positions at each stage of the maximal exercise tests but did change in response to increasing workloads. These results suggest that rider position does not enhance or diminish the cardiorespiratory response to maximal cycle ergometry as the responses to each position are similar. / Master of Science

The transition from cycling to running has been identified as one of the key determinants of success in triathlon, as it has been suggested that the cycle may affect subsequent running efficiency such that running performance is significantly altered or reduced. It is also suggested that athletes more adapted to the transition itself, rather than purely running or cycling, may be more efficient during the post-cycle running bout. The current study sought to investigate the effects of prior cycling on subsequent selected biomechanical, physiological and perceptual responses of three different athlete groups. Subjects were selected on the basis of their sporting background, and were divided into three groups – triathletes, cyclists and runners. Experimentation required subjects to perform a seven minute treadmill running protocol at 15km.h⁻¹, during which biomechanical (EMG, Stride rate, Stride length, Vertical acceleration), physiological (HR, VO₂, EE) and perceptual (RPE) responses were recorded. After resting, subjects were required to perform a twenty minute stationary cycle at 70% of maximal aerobic power (previously determined), immediately followed by a second seven minute treadmill running protocol during which the same data were collected and compared to those collected during the first run. Biomechanical responses indicate that the cycle protocol had no effect on the muscle activity or vertical acceleration responses of any of the three subject groups, while the triathlete group significantly altered their gait responses in order to preserve running economy. The triathlete group was the least affected when considering the physiological responses, as running economy was preserved for this group. The runner and cyclist groups were significantly affected by the transition, as running economy decreased significantly for these groups. Perceptual responses indicate that athletes more experienced with the transition may find the transition from cycling to running to be easier than those inexperienced in this transition. It is apparent that a high intensity cycle protocol has limited statistical impact on selected biomechanical responses, while physiological and perceptual responses were altered, during a subsequent run, regardless of athlete type. That said, the ability of transition-trained athletes to transition comfortably between disciplines was highlighted, which may have important performance implications.

The purpose of this study was to examine the effects of acute aerobic exercise on cardiovascular reactivity to psychological stress. Twenty-four trained male cyclists (aged 19-26) from local cycling teams and clubs in the Blacksburg, Virginia area participated in this exercise study. These subjects cycled a minimum of 4 times per week, 30 minutes per session and were randomly assigned to either the Cold Pressor (CP) or Stroop Color Word (SCW) tasks. All subjects participated in exercise and control sessions. The exercise session consisted of 30 minutes at 70% VO₂ max and the control session involved several health assessments with no exercise. There was no significant difference in blood pressure (BP) or heart rate (HR) change scores (peak-baseline) for treatment or interaction effects. Baseline and recovery systolic blood pressure (SBP), however, showed significant differences for the main effect of treatment (exercise vs. control) (p<.05); interaction effects had a tendency toward significance (p=.09) for baseline SBP. These differences in baseline prompted a re-analysis to statistically explore a possible reduction in anticipatory response to psychological stressors. No treatment or interaction effects were found in this secondary analysis. The results of this study provide only limited support for the hypothesis that acute aerobic exercise reduces BP response to subsequent non-exercise stressors. The effects, if present at all, appear to be stronger in the baseline or anticipatory period. Future research designs should be capable of specifically examining effects in the anticipatory period. These results also provide little support for a selective effect of aerobic exercise on BP reactivity based upon the type of stressor presented. / Master of Science