Effect of 4 wk of deep water run training on running performance.

The purpose of this study was to determine whether trained competitive runners could maintain on-land running performance using 4 wk of deep water run training instead of on-land training. Eleven well-trained competitive runners (10 males, 1 female; ages, 32.5 +/- 5.4 yr; height, 179.8 +/- 9.3 cm; weight, 70.4 +/- 6.7 kg (mean +/- SD)) trained exclusively using deep water run training for 4 wk. Subjects trained 5-6 d.wk-1 for a total of 20-24 sessions (mean +/- SD, 22 +/- 1.5 sessions). Instruction and practice sessions were conducted prior to the training period. Before and after the deep water run training, subjects completed a 5-km race on the treadmill using a computer based system, a submaximal run at the same absolute workload to assess running economy, and a combined lactate threshold and maximal oxygen consumption test. No significant differences were found for (mean +/- SEM): 5-km run time (pre, 1142.7 +/- 39.5 s; post, 1149.8 +/- 36.9 s; P = 0.28), submaximal oxygen consumption (pre 44.8 +/- 1.2 mL.kg-1.min-1; post, 45.3 +/- 1.5 mL.kg-1.min-1; P = 0.47), lactate threshold running velocity (pre, 249.1 +/- 0.9 m.min-1; post, 253.6 +/- 6.3 m.min-1; P = 0.44), or maximal oxygen consumption (pre, 63.4 +/- 1.3 mL.kg-1.min-1; post, 62.2 +/- 1.3 mL.kg-1.min-1; P = 0.11). Also no differences were found among Global Mood State pre-training, each week during training, and post-training. Competitive distance runners maintained running performance using 4 wk of deep water run training as a replacement for on-land training.

Run training versus cross-training: effect of increased training on circulating leukocyte subsets.

The purpose of this study was to determine the effects of increased training via cross-training (run + cycle) and run training on circulating leukocyte subsets. Male runners (N = 11) participated in two randomly assigned increased training (IT) periods after 30 d of normal training (NT). Each IT began after a 14 d period of reduced training (80% of NT) followed by 10 d of IT (200% of NT). During IT, the subjects ran in the afternoon for 10 d (100% NT) and performed 8 additional training sessions in the morning (100% NT) on a treadmill (ITRT) or a bicycle ergometer (ITCT). Blood samples were obtained before (D0), on day 5(D5) and after 10 d (D11) of ITRT and ITCT. A significant increase in the CD4+/CD8+ ratio occurred at D5 compared with D0 and D11. The CD4+/CD8+ ratio was significantly lower during ITRT compared with ITCT at D11. The number of circulating CD3+, CD4+, and CD8+ cells were significantly reduced at D11 compared with D0. In conclusion, 10 d of IT resulted in a significant reduction in the number of circulating T cells independent of the training mode and a reduction in the CD4+/CD8+ ratio for ITRT but not for ITCT.

Exercise training does not alter cytochrome P-450 content and microsomal metabolism.

The purpose of this investigation was to determine whether increased endurance exercise capacity alters total hepatic cytochrome P-450 content and cytochrome P-450 (CYP1A and CYP2B) mediated hepatic microsomal mixed-function oxidase drug metabolism. Twenty adult male Sprague-Dawley rats were randomly assigned to either a control (C) or an endurance trained group (ET). ET rats were progressively trained 5 d.wk-1 for 11 wk. Both C and ET rats were administered in random order single posttraining doses of probe drugs theophylline (probe for CYP1A) and antipyrine (probe for CYP2B). Soleus muscle citrate synthase activity of ET rats was significantly greater (P < 0.01) than for C rats (mean +/- SD; C, 26.4 +/- 1.3 mumol.g-1.min-1; ET, 46.1 +/- 2.7). In contrast, total liver cytochrome P-450 content was not significantly different (P > 0.01) among C and ET rats (mean +/- SD; C, 0.554 +/- 0.055 nmol.mg-1 liver protein; ET, 0.604 +/- 0.080). Likewise, the posttraining C and ET single-sample plasma clearances of theophylline (mean +/- SD; C, 1.89 +/- 0.360 1.h-1.kg-1 total liver weight; ET, 2.08 +/- 0.49) and antipyrine (mean +/- SD; C, 6.44 +/- 1.56 1.h-1.kg-1 total liver weight; ET, 6.51 +/- 1.02) were not significantly different (P > 0.01). Therefore, it was concluded that strenuous endurance training of 11 wk duration did not alter total hepatic cytochrome P-450 content or CYP1A or CYP2B activity.

Opioid receptor modulation of postexercise hypotension.

Previous studies of both hypertensive and normotensive individuals have indicated a prolonged reduction in blood pressure for several hours after aerobic exercise. In related studies of spontaneously hypertensive rats, this postexercise hypotension has been prevented with naloxone. The purpose of the present investigation was to examined whether the postexercise hypotension may be reversed by antagonism of opioid sensitive receptors with naloxone in normotensive humans. Eight males 22-34 yr of age, participated in two 60-min cycling trials at 60% of VO2 peak, followed by 29 min of recovery. Beginning at 7-min recovery, naloxone or saline (control) was administered intravenously through an indwelling catheter. Blood pressure and heart rate were monitored every 15 min during exercise and every 2 min during recovery. Heart rate was significantly elevated (P < 0.05) over basal levels for the first 11 min of recovery, but from 13 to 29 min was not different from that measured at rest. In both trials, after 11 min of recovery, systolic and mean arterial blood pressures were significantly (P < 0.05) lower than pre-exercise levels (9 +/- 1 mm Hg and 4 +/- 1 mm Hg, respectively). Injection of naloxone (0.1 mg.kg-1) reversed the hypotensive response. However, the reversal was transient, lasting from minutes 15 to 27. Since naloxone reverses postexercise hypotension, opioid sensitive receptors appear to be involved in the reduction in systolic blood pressure following a single bout of submaximal exercise in normotensive humans.

Perceptions of current and ideal body shape of athletes and nonathletes.

This study was done to examine the relationship between sex and perception of body image among athletes and nonathletes. A total of 211 men and women athletes and nonathletes completed a questionnaire which asked them to identify from a nine-figure body-silhouette scale their current image and the image that they thought was most ideal. t tests showed no significant differences for men based upon athletic participation and that both athletes and nonathletes were satisfied with their body image. However, when comparing current image and ideal image, significant differences were found for women athletes and nonathletes. These data support previous research documenting women's dissatisfaction with their body images and show athletic participation is not associated with this perception.

Cardiovascular responses and anaerobic threshold for bicycle and arm ergometer exercise.

Cardiovascular responses occurring at the anaerobic threshold (AT) were compared during intermittent bicycle and arm ergometry in eight healthy college students. Arm and bicycle tests used time-matched, discontinuous protocols (three-minute work stages alternated with three-minute rest intervals). Anaerobic threshold was determined by plotting expired minute volume (Ve) on oxygen consumption (VO2) and expressed as the percentage of the respective peak VO2 at which the deflection occurred. Analysis of variance revealed AT was similar for arm and bicycle tests. Absolute VO2 at AT was higher for bicycle than for arm ergometer exercise (p less than .05). Heart rate (HR) and rate pressure product (RPP) were higher for bicycle than for arm ergometry at AT (p less than .05). Moreover, a similarity in percent maximum RPP and percent maximum VO2 was observed at AT for arm ergometry, whereas percent maximum RPP was higher than percent maximum VO2 at AT for bicycle ergometry. Because AT has been suggested as an appropriate intensity of exercise for conditioning, it was concluded that a sufficient level of exercise intensity can be elicited at a lower percentage of the cardiovascular reserve for arm than for bicycle ergometer exercise.

Variations in cardiovascular response accompanying differences in arm-cranking rate.

Arm ergometry may be the only means of exercise testing for persons who cannot perform treadmill or bicycle ergometer testing. To determine the effects of arm-cranking rate on cardiovascular responses, ten healthy college students underwent maximal graded exercise testing on the arm ergometer. Each subject completed randomly ordered tests using 30-, 60-, and 70-rpm cranking rates at least seven days apart. Analysis of variance (ANOVA) indicated that both peak heart rate (HR) and rate pressure product (RPP) increased significantly with increases in cranking rate across the three tests (p less than .05). Peak systolic blood pressure (SBP) and oxygen uptake (VO2) for the 60- and 70- rpm tests was significantly higher than for the 30-rpm test (p less than .05). Peak work rate (WR) was significantly higher for the 70-rpm than for the 30-rpm test (p less than .05). Because RPP is an accepted index of myocardial oxygen consumption, the results indicated that the metabolic load on the heart was increased by increments in the cranking rate. The increases in RPP occurred as a function of the combined increases in HR and SBP as rpm increased from 60 to 70. Since increases in WR and VO2 did not occur as rpm increased from 60 to 70, the rise in HR and RPP may have occurred in response to factors other than the total-body oxygen demand.

Nonprescription chlorpheniramine maleate and submaximal exercise responses.

OBJECTIVE: To determine if a single, over-the-counter dose of the H1 antagonist chlorpheniramine maleate (CM) alters total peripheral resistance (TPR) and oxygen uptake (VO2) during submaximal exercise. DESIGN: The study was a prospective, longitudinal, double-blind, random crossover analysis of the cardiovascular and respiratory responses to a single bout of moderately intense exercise. SETTING: Exercise tests were conducted in an exercise laboratory equipped with expired gas analysis and bioelectrical impedance cardiographic monitoring capabilities. PARTICIPANTS: Subjects were 18 (9 men, 9 women) volunteers (age=29.5+/-3.6yrs; weight=70.7+/-1.1kg), free from exercise-limiting pathology and rhinitis. INTERVENTION: Each subject completed a maximal exercise tolerance test on the cycle ergometer followed by two randomly ordered submaximal exercise tests at a power output of 50% of the peak power attained on the maximal test: the first, 2 hours after ingesting 4mg of CM, the second, 2 hours after ingesting a placebo. The submaximal exercise tests lasted 20min and data were recorded at 5, 10, 15, and 20min of exercise during both the CM and placebo tests. Tests were completed approximately 48 hours apart. RESULTS: Average VO2 was 1,488+/-367mL/min for the CM test and 1,477+/-351mL/min for the placebo test. TPR was 12.3+/-7.4PRU for the CM and 11.3+/-4.5PRU for the placebo tests. Analysis of variance revealed that these scores were statistically similar. CONCLUSION: A single over-the-counter dose of CM does not alter TPR or VO2 during submaximal exercise.

Serum haptoglobin and ferritin during a competitive running and swimming season.

The purpose of the study was to examine ferritin, haptoglobin, and red cell indices during a competitive running and swimming season. Male runners (N = 8) and swimmers (N = 5) were tested four times during their respective seasons. The runners were tested before the start of organized practice (RT1), after 3 wk of increased training (RT2), 3 wk prior to the conference championship (pre-taper, RT3), and 3 d after the conference championship (post-taper, RT4). The swimmers were tested after the first 9 wk of training (ST1), after completing 2 wk of hard training (ST2), after an additional 6wk of training (pre-taper, ST3), and 1 wk following the conference championship (post-taper, ST4). For the runners, hemoglobin, hematocrit, and red blood cell number were lower (p < 0.05) at RT2 and were not accompanied by significant changes in other red cell indices or haptoglobin. Serum ferritin in the runners was lower at RT3 and RT4 compared to RT1 despite an adequate dietary iron intake. Hemoglobin and mean cell hemoglobin concentration were lower and mean cell volume was higher in the swimmers at ST3 and ST4. No significant changes were observed in other red cell indices for swimmers; however, serum haptoglobin tended (p = 0.07) to be reduced at ST2. In conclusion, collegiate male runners and swimmers do not demonstrate clinical hypoferritinemia, hypohaptoglobinemia, or alterations in red cell indices suggestive of the early stage of anemia with or without iron deficiency during their respective season.

Resistance exercise effects on plasma cortisol, testosterone and creatine kinase activity in anabolic-androgenic steroid users.

Anabolic-androgenic steroids (AS) users have been reported to have an improved ability to withstand exhaustive resistance workouts and to recover more rapidly. The purpose of this investigation was to study the effects of AS usage on the cortisol (C), testosterone (T) and creatine kinase (CK) response to a resistance training session. Eleven trained body builders and power lifters (5.0 +/- 1.6 training years, mean +/- SD), 5 AS users (SU) and 6 nonusers (NU), completed a standardized resistance training session consisting of 10 sets of back squats at preset percentages of the subject's 1 RM max. Blood samples were obtained at rest, immediately post exercise and 24 hours after the exercise session. SU had significantly lower T at rest. Neither group exhibited a significant change in T at 1 min or at 24 h post exercise. Both the NU and SU exhibited a significant increase in CK at 1 min post exercise (129 +/- 23.3 U.l-1, 81 +/- 15.3 U.l-1, respectively), with the NU response significantly greater than the SU. After 24 h, CK for NU was significantly elevated (171.9 +/- 54.5 U.l-1) above resting level. In contrast, CK for SU had returned to resting level. NU had a significant increase in cortisol (C) (p less than 0.05) at 1 min post exercise (156.8 +/- 10.9 nmol.l-1), while the SU cortisol was not significantly changed. By 24 h C for the NU returned to resting level. The results of this investigation support the concept that AS users have a diminished CK response and an altered stress response to a single bout of resistance exercise.

Indices of training stress during competitive running and swimming seasons.

Eight male cross-country runners and five male swimmers were tested four times during their collegiate seasons. Each trial corresponded to a different training load. The runners' trials were conducted before the start of organized practice (RT1), after 3 wk of increased training (RT2), 3 wk prior to the conference championship (pre-taper, RT3), and 4 d after the conference championship (post-taper, RT4). The swimmers' trials were conducted after the first 9 wk of training (ST1), after completing 2 wk of hard training (ST2), after an additional 6 wk of training (pre-taper, ST3) and during a week following the conference championship (post-taper, ST4). Venous blood samples, heart rate (HR) and blood pressure (BP) were obtained after 15 min supine rest (0700 h). Serum was analyzed for cortisol (C), total testosterone (TT), free testosterone (FT), and creatine kinase (CK). Blood samples (lactate), HR and RPE were obtained during a fixed velocity run (75% preseason VO2max) and blood samples and RPE following a 365.8 m swim (90% preseason VO2max). The runners then completed a "performance run" to exhaustion (110% preseason VO2max) and the swimmers completed maximal 22.9 and 365.8 m swims. Serum CK, C, TT, FT, and the TT:C and FT:C ratios were not significantly different among trials for the runners. Serum TT and FT were significantly (P < 0.05) lower for the swimmers at ST2 (TT 16.7 +/- 2.5; FT 85.3 +/- 8.5) compared to ST1 (TT 30.3 +/- 2.8; FT 130.2 +/- 20.9) whereas, C, TT:C or FT:C were not significantly altered.(ABSTRACT TRUNCATED AT 250 WORDS)