This investigation assessed the effects of acute aerobic exercise (AE) on cardiovascular reactivity (CVR) to a non-exercise stressor. Nineteen untrained, healthy male volunteers were stratified on diastolic blood pressure (DBP) response to the cold pressor test (CPT), then randomly assigned to either a minimal exercise condition (5 min of freewheel cycling) or 30 min of exercise on a bicycle ergometer at 55-60% V02max. Heart rate (HR) and BP were monitored during the resting, arousal, and recovery phases of the CPT at 1 hr, 3 hr, and 24 hr post-exercise. Results revealed statistically non-significant response and recovery effects; however, two important trends emerged. The 30 minute exercise group exhibited a tendency toward a reduced DBP response to the CPT during the 1 hour post-exercise session (p=0.08) and SBP response to the CPT was lower in the 30 minute exercise group at 3 hours post-exercise (p=0.08). These findings provide only minimal support for the effectiveness of 30 minutes of AE at 55-60% V02max in attenuating physiological response to the CPT in untrained males. / Master of Science

Evidence from various studies indicates that eccentric contractions produce more post-exercise changes in muscular function than do concentric contractions. Delayed muscular soreness, the pain and tenderness present 1 or 2 days after exercise, is negatively correlated with muscular performance and occurs particularly after eccentric work. The action of an analgesic, anti-inflammatory drug (Indocin) on muscular soreness indicates it may be effective in accelerating recovery of muscle function after eccentric work. In the study reported herein the effects of Indocin on muscular performance, as evaluated on the Cybex II isokinetic dynamometer, following prolonged concentric and eccentric work, were evaluated in 48 subjects who were randomly assigned to one of four drug groups. Subjects performed a 30 minute step test during which one limb led the stepping movement throughout (concentric contractions) and the contralateral limb trailed throughout (eccentric contractions). The muscular performance parameters of peak torque (PT), torque acceleration energy (TAE) and average power (AVP), evaluated at slow and high velocities, and the range of motion (ROM) at the knee joint were assessed prior to the step test and at five intervals thereafter. A non-significant decrease in PT and TAE at the contraction speed of 60 deg/sec were present in the eccentric limbs, greater reductions evidenced in the placebo group. Non-significant changes occurred in the concentric limbs, Non-significant changes in ROM and in muscular function parameters evaluated at 250 deg/sec were observed. / Master of Science

The effect of aerobic exercise and fish oil supplements on plasma lipid parameters was investigated in the hamster. The hamsters were fed a basal hypercholesterolemic purified diet (0.1% cholesterol, 15% fat) to elicit an elevated lipid response. Fifty-six hypercholesterolemic hamsters were divided into four groups: control, swimming (trained up to one hour every other day), daily fish oil supplementation (.35g/kg/day omega-3), and a swimming/fish oil combination. The effect of these treatments on plasma TC, TG and pooled samples of plasma HDL-C, HDL2â C, LDL-C and VLDL-C was studied over 12 weeks. All hamsters had a significant increase in body weight. Feed intakes increased at 6 weeks and then declined over the second 6 weeks, but remained above the beginning levels. / Master of Science

Previous investigations have shown the benefits of aerobic dance and bench step training programs. Their main focus has been to examine cardiovascular improvements and caloric expenditure during these activities. Therefore, the purpose of this study was to examine the effects of exercise mode on isokinetic strength, power, and endurance of the quadriceps. Twenty-nine non-smoking, free from history of knee pathology, non-physically active females (20.6 ± 2.8 years, 160.6 ± 4.9 cm, 61.9 ± 16.5 kg) volunteered for this investigation. Non-randomized testing procedures were performed due to the nature of the study. Of the 29 subjects, there were n=11 in the step Aerobic (SA) group, n=8 in the High Impact (HI) group, and n=10 in the Control (CT) group. Subjects were tested twice for quadriceps muscle function utilizing the following isokinetic tests: Peak Torque (PT) , Peak Torque to Body Weight Ratio (PTBW), Average Power (AVP) , and Endurance Ratio (END) on the Cybex 11+ isokinetic machine before and after the 12-weeks of exercise training. / Master of Science

Only a small number of the subjects who enter treatment For obesity maintain their target weight. Explanations for this include increased food efficiency and alterations in resting metabolic rate (RMR). The RMR has been shown to be reduced after weight reduction and it is believed that a benefit of exercise training is an adaptive increase in lean body weight (LBW) with a concurrent decrease in excess body fat. Since caloric restriction is essential for weight reduction, an increase or preservation of LBW is desirable. The purpose of this study was to assess the effect of caloric restriction (DO group; n = 6) and caloric restriction plus weight training (DWT group; n = 8} on total weight (TW), percent fat (% fat), lean body weight (LBW), and RMR during an 8 week study. Both groups met 3 days/week for 30-45 min/day to perform a specific exercise or flexibility routine. The DWT group performed three sets of ten lifts on seven resistive exercises, under supervision, while the DO group performed a set routine designed to increase flexibility but result in no appreciable exercise. Subjects met weekly with a Registered Dietitian to provide information regarding nutritional and caloric content of Food, as well as behavior modification techniques. Results revealed non-Significant treatment effects between the groups on the variables RMR, % fat, and LBW. A treatment effect was observed for TW, with the DO group significantly losing more weight. Total weight and % fat significantly decreased in both groups from pre to posttest. A significant difference was noted for the DWT group from 4 weeks - 8 weeks in RMR, although there was no effect from baseline - 8 weeks. Thus, resistive exercise when added to caloric restriction, increases strength, but results in Slower weight loss when compared to diet only subjects while resulting in similar losses in % fat and total weight. / Master of Science

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

Forty-five males volunteered to serve as subjects to investigate the effects of limb velocity and limb preference on peak torque/body weight (PTBW), torque acceleration energy (TAE), average power (AVP), and endurance ratio (ER) at isokinetic speeds of 60 and 300 degrees/second during internal and external rotation of the shoulder. Standard Cybex warm-up and test protocol were used for both test conditions. Test/retest reliability estimates ranges from r=.60- .70. Repeated Measures ANOVA revealed significant limb speed and limb preference effects on PTBW, TAE, and AVP in both exercise speed or limb preference. The data illustrate a need for an internal/external shoulder rotation normative profile specific to limb speed and limb preference. / Master of Science

The effects of exercise training and iron intake on iron metabolism in adult female rats were investigated. Adult female Sprague-Dawley rats were assigned to either an exercise (E) or sedentary (S) group and fed either a diet containing 9 ppm (9) of dietary iron (low iron level), or 40 ppm (40) of iron (a level slightly above the National Research Council recommendations). The exercise animals were subjected to a program of swimming, 5 days/week, over a 6- week period. Total food intake and final body weight were similar between the E and S groups. In both 40-E and 9-E animals, concentration of serum iron was significantly (P<0.05) lower while total iron binding capacity was significantly elevated, when compared to sedentary counterparts. Saturation of transferrin was significantly reduced in the 9-E group. Liver and spleen weights did not differ but significant increases in cardiac weights were noted in both E groups. Gastrocnemius muscle weights were similar in both E groups and 9-S, but significantly lower in the 40-S group. In organ tissues, liver iron concentration was significantly reduced in the 9-E animals, while spleen iron level was highest in the 40-E group. Cardiac iron concentration was significantly reduced in both E and low iron diet groups while levels of iron in gastrocnemius muscle did not differ among experimental groups. In both groups of exercised rats, bone marrow iron was significantly lower when compared to sedentary animals. In response to exercise training, an increase in skeletal muscle citrate synthase activity was observed in both E groups. This study suggests that exercise affects various parameters of iron metabolism. Regardless of iron intake, physical training appeared to alter distribution of iron stores, that may be associated with alterations of hematological iron transport and iron-containing proteins. The Combination of a low iron intake and intense exercise training appeared to enhance early characteristics of a latent iron deficiency. / Ph. D.

Thesis (MSc (Physiological Sciences))--University of Stellenbosch, 2006. / Despite a growing interest into the mechanisms of the repeated bout effect, little is known about the consequences of chronic eccentrically biased training and the possible advantageous such training may offer to athletes as well as patients with muscle-debilitating disease. This study investigated the role of satellite cells in the muscle adaptation in response to either downhill or uphill high intensity training (HIT). Welltrained endurance runners were divided into two training groups matched for training volume and 10 km running times (n = 6, uphill training, UP; n = 6, downhill training, DH) and subjects in both groups completed 10 HIT sessions over a period of 4 weeks. Running performance was tested before and after the training intervention by a 10 km road race and peak treadmill speed (PTS) in horizontal and inclined (+5%) laboratory incremental tests to exhaustion. Skeletal muscle biopsies were sampled at baseline, after 2 HIT sessions, and after 4 weeks of HIT. Muscle was analysed immunohistochemically for satellite cell frequency as identified by CD56 and M-cadherin (Mcad) expression. Myogenin protein contents of muscle homogenates were determined by western blotting. Myosin heavy chain (MyHC) isoform proportions and mean fibre crosssectional area was measured. During the HIT intervention, UP exercised at a higher percentage of their HRmax than DH (mean ± SD, 97 ± 1 vs. 92 ± 3 %HRmax, p < 0.005), but at a similar rate of perceived exertion (RPE). DH completed more intervals per session and covered greater distance per session than their UP counterparts. Both training groups increased their training intensity but decreased their training volume during the 4 weeks of HIT. The combined group of 12 athletes improved their PTSgradient (mean ± SD, 16.7 ± 0.8 vs. 17.3 ± 1.0 km/h, p < 0.05). No significant differences between groups were found for PTS, VO2max or 10 km performance. Satellite cell frequency in this cohort of trained runners (48.9 ± 10.3 km/week) at baseline was similar to healthy young males (CD56+ cells/fibre, 0.19 ± 0.10). Satellite cell frequency increased significantly in DH after 4 weeks (Mcad, 123%; CD56, 138%) and non-significantly in UP (Mcad, 45%, CD56, 39%). No significant differences were found after two training sessions or at any time between groups. Mcad and CD56 expression correlated well (r = 0.95, p < 0.0001). Muscle myogenin content increased for both groups (UP: 56%; DH: 60%) after 4 weeks. No notable changes were seen after two training sessions. However, myogenin levels 2 days after session 1 correlated well (r= 0.99, p<0.005) with muscle pain experienced on the same day, as measured by the visual analogue scale. No changes were seen in the MyHC proportions or the fibre cross-sectional area after the training intervention. It was concluded that the training intervention was too short to induce changes in MyHC distribution or fibre area. Is seems likely that satellite cell proliferation was initiated as an early response to DOMS, but the response was maintained for 4 weeks. However, due to the lack of change in fibre morphology and myonuclear number, the role of satellite cell proliferation in fibre type transformation or muscle hypertrophy could not be established. Similarly, various possible roles for increased myogenin protein are offered, but since the origin of myogenin expression (satellite cells vs. myonuclei) was not determined, no definite conclusion regarding the precise function can be made. In conclusion, this study is the first to definitively indicate satellite cell proliferation in well-trained endurance runners in response to a change in training, including specifically downhill HIT. This response was early and sustained. This study asks several questions about the role of satellite cells during muscle adaptation to repetitive downhill training, and lays a foundation for further research into this unexplored field.