Perceptual responses and blood lactate concentration: effect of training state.

The present study investigated the effect of training state on ratings of perceived exertion obtained at the lactate threshold (LT) and fixed blood lactate concentrations (FBLC) of 2.0, 2.5, and 4.0 mM. Runners (N = 20) and nonrunners (N = 29) completed a progressive horizontal treadmill (TM) running test which allowed identification of the TM velocities associated with the LT and FBLC. Runners attained significantly higher TM velocities, greater VO2, greater VE, greater heart rate, and a lower ventilatory equivalent for oxygen (VE/VO2) at each exercise intensity, with the exceptions of heart rate at 4.0 mM and VE/VO2 at the LT. Compared to nonrunners, runners also attained higher VO2, VE, and heart rate relative to peak values at LT and 2.0, 2.5, and 4.0 mM. Despite these relative and absolute physiological differences, there were no differences between groups in local, central, or overall ratings of perceived exertion (RPE) (Borg scale) at any condition. The data from both groups were combined to give the following means and SD for overall RPE during horizontal running: at the LT-11.0 +/- 2.0, and at FBLC of 2.0 mM-13.7 +/- 2.1, 2.5 mM-14.5 +/- 1.8, and 4.0 mM-16.5 +/- 2.3.

Fitness profiles and activity patterns of entering college students.

Fitness levels of American youth have shown a marked decline in the last decade, according to recent studies. To determine whether such a tendency persists for entering college students, the authors evaluated 115 male and 143 female students for performance on the following fitness-related variables: (1) maximal oxygen consumption (estimated from Astrand cycling protocol), (2) body composition (skin-fold techniques), (3) muscle endurance (sit-up protocol), (4) muscle strength (bench-press protocol), and (5) joint flexibility (upper and lower body protocols). Although neither men nor women exhibited high levels of cardiorespiratory fitness, the women in the study showed higher relative levels than their male counterparts. Both groups showed excellent levels of muscle strength (compared with normative standards), but they achieved only an average standard for muscle endurance. Findings of relatively low levels of cardiovascular fitness compared with levels of muscle strength, particularly in men, seem to be a reflection of an inappropriate concentration of physical activity.

Athletic injury and self diminution.

A review of the literature examining the effects of athletic injury on persons have suggested a deleterious effect. Specifically, results indicated that following traumatic injury, athletes suffer a diminution of affect and feelings of self-worth. Because studies published in this area have been post-injury in design, the present study was fashioned to examine changes from baseline values in the self-concept of university varsity football players following a disabling injury. There were 29 athletes in the subject pool. Sixteen subjects were severely injured during the season. Measures were taken on the first day of fall practice and at the end of the season. Injured athletes were assessed each week while they were unable to participate in practice. Analysis revealed a significant decrease in generalized self-concept following athletic injury (p < 0.001) which persisted through the course of treatment. Suggestions for continued research and treatment are proffered.

Exercise dependence in relation to competitive orientation of runners.

An increasing number of runners seem to be vulnerable to the exercise dependence (ED) syndrome, a clinical disorder in which the athlete is unwilling to alter or discontinue training regimens despite medical contraindications to continued training compliance. As habituation to a stimulus has been regarded to be a diagnostic criterion of an addicted state, we hypothesized that performance in running events of increasing distances would be accompanied by an increased tendency towards ED. To examine this relationship, an exercise addiction scale was completed by recreational (non-competitive) runners (N = 33), five kilometer (5K) runners (N = 24), marathoners (N = 32), and ultramarathon (50 miles) runners (N = 61). ANOVA procedures indicated that both marathoners and ultramarathoners showed significantly higher ED scores [3.78 +/- 1.6 (SD) and 4.59 +/- 1.8, respectively] as compared to 5K (2.9 +/- 1.0) and recreational runners (2.16 +/- 1.3) (p < 0.05). In addition, ultramarathoners presented significantly higher ED scores than those of marathoners (p < 0.05). The data indicate that a tendency towards ED may motivate participation in competition of increasing distance and support a habituation effect consistent with acquired dependence behavior.

Mood alterations in older adults following acute exercise.

Limited research indicates positive affective change following acute bouts of exercise, but whether this improved affect among younger subjects may be generalized to older individuals is not known. The present study, then, examined the effects of a single bout of physical activity among older participants. 16 trained women (Mage = 64.5 +/- 7.6 yr.) completed an abbreviated Profile of Mood States prior to and immediately following a 75-min. session of aerobic line dancing. A series of one-way analyses of variance with repeated measures were used to examine differences between pre- and posttest subscores on mood states. Significant decreases following exercise in scores on Tension, Depression, Fatigue, and Anger and a significant increase in scores on Vigor relative to preexercise (control) scores were found. Global mood was significantly improved after the exercise session. No significant difference was found between pre- and postexercise measures of Confusion. Previous findings of significant improvements in affect immediately after an acute bout of exercise may be generalized to older adults. Repetition with a nonexercised control group is desirable.

Distortion of body image among elite female dancers.

To examine body image and possible distortion of body image among elite female dancers 10 members of a professional ballet company rated both current and ideal body shape. In addition, an objective measure of body composition was obtained via skinfold techniques. t tests indicated that the mean rating for current body image was significantly higher than the rating for ideal, despite the fact that body-composition measures for all subjects were in an "ideal" range according to normative standards. Analysis indicated a high distortion of body image among these dancers and support psychophysiological concerns previously raised.

Exercise dependence among competitive power lifters.

Scores on exercise dependence examined among a sample of 14 competitive power lifters showed higher exercise dependence among lifters than those previously reported for endurance athletes.

Mood alterations with a single bout of physical activity.

Although numerous studies have examined the relationship among affect, personality, and physical activity, results are equivocal. Critics have cited inadequate experimental designs and analyses as the bases for ambiguity. This study addressed two identified weaknesses, length of exercise regimen and improper selection of subjects. Subjects were 72 college-age students who participated in one of three 75-min. activity classes (running, karate, weight lifting) and a lecture class (control subjects). The Profile of Mood States Test was administered prior to and immediately after exercise bouts. Analyses of variance and multiple t tests indicated that participating in a single bout of exercise significantly reduced reported total mood disturbance, tension, depression, anger, and confusion.

Sex differences on exercise dependence for men and women in a marathon road race.

Considerable research has documented a tendency towards exercise dependence among habitual exercisers; however, little research on possible differences in exercise dependence among men and women has been done. This question seems worthy of study given associations between exercise dependence and eating behavior problems and a greater incidence of eating disorders among women than men. Subjects, 18 men and 14 women competing in a marathon road race, completed an exercise dependence survey developed by Hailey and Bailey in 1982. There are 14 equally weighted items which focus exclusively on psychological rather than physiological aspects of exercise dependence. Analysis of variance indicated the women reported significantly higher scores (3.9 +/- 1.7) than men (3.7 +/- 1.2, p < .05). While the design does not allow assessment of mechanisms underlying the result, one may express concern about the motives for participation in athletic competition.

Scores on exercise dependence among dancers.

A number of researchers have suggested that the syndrome of exercise dependence (addiction) is paralleled by a tendency towards eating disorders such as anorexia nervosa and bulimia. As considerable research has reported a high incidence of eating disorders among dancers and as rigorous physical demands are inherent in dance, we hypothesized that dancers would present a higher profile of exercise dependence on the Negative Addiction Scale than other athletes. To test this hypothesis, 47 female ballet and modern dancers completed a survey on exercise dependence adapted from Hailey and Bailey (1982) to assess quantitatively exercise dependence. Scores were compared with those obtained from 39 female endurance (running) athletes and 16 female nonendurance (field hockey) athletes. Significantly higher scores on dependence for dancers than for endurance or nonendurance athletes were noted. The data indicate that dancers may be at greater risk for psychophysiological problems associated with exercise dependence than other athletes and so should be monitored for symptoms.

Beta-endorphin response to endurance exercise: relationship to exercise dependence.

Considerable research has shown significant increases in beta-endorphin levels after aerobic activity. These increases and their accompanying euphoric effect have been suggested as a possible psychophysiological mechanism underlying the exercise-dependence syndrome. The relationship between plasma beta-endorphin levels and a tendency towards exercise dependence, however, has not been established. To examine this relationship, 8 women trained in aerobic dance completed an exercise-dependence assessment prior to participation in a 45-min. session of continuous aerobic dance. Plasma beta-endorphin concentration was measured both prior to and following the aerobics routine. A Student t test for paired observations indicated that mean plasma beta-endorphin levels (+/- SE) were significantly higher after the aerobics routine (11.96 +/- 1.3 pg beta-EP.ml-1) than preexercise levels (8.62 +/- 1.4). However, beta-endorphin difference values (% change) were not significantly correlated with scores on the exercise-dependence survey. Those data suggest that scores on exercise dependence are not related to changes in plasma beta-endorphin levels after aerobic exercise.

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.

Metabolic demands and perceived exertion during cardiopulmonary resuscitation.

Emergency situations often require continuous execution of one-person cardiopulmonary resuscitation (CPR) for periods of time in excess of 30 minutes. The limited research which has examined the demands of the procedure has focused on central physiological measures, despite (1) the use of a subjective end-point for termination of CPR (i.e., exhaustion) as stated in professional guidelines, and (2) significant peripheral involvement in the form of muscular exertion, a phenomenon more closely linked to Ratings of Perceived Exertion (RPE) than to central factors. To examine subjective responses to performing CPR, 8 healthy, sedentary subjects [M age = 20.8 (yr) +/- .4; weight (kg) 82.6 +/- 7.1; height (cm) 183.7 +/- 2.8] reported differentiated Ratings of Perceived Exertion (RPE) following 10 minutes of one-person CPR testing. While metabolic data observed during CPR support previous research suggesting that the energy demands of performing CPR are relatively low, both peripheral and over-all RPE were significantly higher than central (respiratory-metabolic) RPE. Over-all RPE was also significantly greater than peripheral RPE. The data suggest research investigating CPR demands based on central measures may underestimate actual as well as perceived demands of performing the procedure. In addition, the considerable interindividual variability in the relative energy cost (% VO2 max) of performing one-person CPR suggests that the fitness level of the individual may be a limiting factor in the ability to perform CPR for extended periods of time.

Beta-endorphins and mood states during resistance exercise.

Research examining the relationship between beta-endorphin immunoreactivity and affect has resulted in equivocal findings. To examine this relationship further, 10 male and 10 female college-age students participated in a controlled free-weight exercise session. Blood plasma samples were procured both prior to and following the exercise bout and beta-endorphin levels were determined by immunoassay. Analysis indicated that plasma beta-endorphin levels following exercise were significantly decreased from pre-exercise levels. Pearson correlations showed no significant relationship between pre- or postexercise plasma beta-endorphins and either total mood disturbance or Profile of Mood States subscores. The data support previous failure of resistance exercise to produce an increase in beta-endorphin immunoreactivity as well as the lack of a significant relationship between affect and the beta-endorphin response to exercise.

The effects of an acute bout of sleep on running economy and VO2 max.

Synchronized human sleep has been shown to decrease activation of the sympathetic nervous system, resulting in reduced levels of oxygen consumption. This is in direct conflict with sympathetic arousal, which coincides with the initiation of exercise. Although a considerable body of research has investigated the effects of sleep deprivation on exercise performance, the effects of an acute bout of sleep on exercise response have not been previously reported. This question appears relevant considering the occurrence of acute sleep bouts among athletes competing in prolonged multi-event competition (e.g. swimming, track and field). To investigate the effects of an acute bout of sleep on submaximal (running economy) and maximal oxygen consumption, seven male volunteers participated in a continuous, progressive treadmill test to volitional exhaustion immediately following a 1-h bout of sleep (SB) or no sleep (Control). The subjects served as their own controls and the order of trials was randomized. A MANOVA with repeated measures indicated no difference between groups for running economy or VO2 (P < 0.05). However, a significant interaction effect was observed in which SB resulted in greater running economy (lower VO2) through the first two stages of the protocol, while the control treatment yielded a greater economy throughout the remaining stages. While the implications of the findings are uncertain, they may indicate differences in psychological arousal or anxiety as a result of treatments or the possibility of a delayed sympathetic arousal in the early stages of exercise following sleep.

Effect of induced alkalosis on swimming time trials.

Previous studies have shown that sodium bicarbonate ingestion prior to exercise may improve performance during repeated (interval) bouts. To examine the practical implications of such findings, seven collegiate swimmers participated in simulated swim competitions of multiple events following sodium bicarbonate (B) ingestion, placebo (P) ingestion and control (C--no ingestion) treatments. Each swimmer reported to the laboratory 1 h prior to the simulated competitions (72 h apart) and was randomly assigned to one of the three experimental treatments. Competition consisted of one relay (100 yards; 91.4 m) and two individual (200 yards; 182.8 m) swimming events with 20 min rest between events. Analysis of variance (ANOVA) with repeated measures revealed no significant differences in performance times as a result of the three treatments (P greater than 0.05). The results suggest that sodium bicarbonate ingestion prior to swim competition consisting of significant rest intervals between events is not an ergogenic procedure.

Effects of training specificity on the lactate threshold and VO2 peak.

We examined the effects of training specificity on the lactate threshold (LT) and VO2peak. Sixteen male subjects completed VO2peak/LT protocols on the cycle ergometer (CE) and treadmill (TM) before and after a training program. The subjects were assigned to run training (N = 5), cycle training (N = 6), and control groups (N = 5). Subjects trained 4 day/week for 10 weeks at approximately 89% of pre-training VO2peak. Results indicated that run training increased VO2 at LT (VO2LT) within both the CE and TM protocols (17.9 to 22.5 ml/kg.min-1 for CE, 22.7 to 36.0 ml/kg.min-1 for TM, p less than 0.05) with the 58.5% increase in VO2LT for TM being greater than the 30.3% increase for CE (p less than 0.05). Cycle training resulted in a 38.7% increase in CE VO2LT (19.7 to 27.4 ml/kg.min-1, p less than 0.05) with no significant improvement in TM VO2LT (23.6 to 24.0 ml/kg.min-1). Similar increases in VO2peak were observed for CE and TM protocols for both cycle and run training groups (VO2peak increased by 11.9 to 20.7% in both CE and TM regardless of training mode). No changes were observed in the control group for any variable. The present data suggest that increases in LT resulting from training may be specific to the mode of exercise.

Resistance exercise decreases beta-endorphin immunoreactivity.

Previous research investigating the response of plasma beta-endorphins (beta-EP) to resistance exercise has resulted in equivocal findings. To examine further the effects of resistance exercise on beta-EP immunoreactivity, 10 male and 10 female college-age students participated in a series of controlled isotonic resistance exercises. The session consisted of three sets of eight repetitions at 80% of one repetition maximum (1-RM) for each of the following exercises: (1) bench press; (2) lateral pull-downs; (3) seated arm curls; and (4) military press. Blood plasma was sampled both before and after the lifting routine and beta-endorphin levels were determined by radioimmunoassay. A Students t test for paired samples indicated that mean(s.e.) plasma beta-endorphin levels after exercise (10.5(1.3) pg beta-EP ml-1) were significantly decreased as compared with pre-exercise (control) levels (16.5(1.2), P < 0.05). While the mechanism(s) contributing to the decrease in immunoreactivity is unclear, it may be the result of the synergistic effect of beta-EP clearance during rest intervals and changes in psychological states between sampling.