Background: The affective response to self-selected and imposed exercise intensities of differing physical stimuli has been previously compared in adults and children. Purpose: The primary purpose of this investigation was to compare the affective response to self-selected (SS) and imposed (IMP) exercise of the same intensity in young, recreationally active adult males. The secondary purpose was to determine if a significant proportion of subjects self-selected exercise intensity above 50% of oxygen uptake reserve (VO2R). Methods: 32 males [mean(SD) age 22.3(2.2), VO2PEAK 3.38(0.59)] participated in the investigation. All subjects performed a load-incremented VO2PEAK test and a 20-min, SS exercise trial on a cycle ergometer. One week later, subjects performed the IMP exercise trial. Subjects in the experimental group (n=16) were unaware that the IMP intensity was the same as that previously self-selected. These subjects were told the intensity was selected by the investigators.‟ Control subjects (n=16) were aware that the intensity of the IMP trial was the same as the SS trial. The affective response measured using Feeling Scale ratings (FS-R) was obtained prior to, during, and following the SS and IMP trials. ÄFS-R values, calculated by subtracting FS-R estimated during the SS trial from that of the IMP trial at each time point, were analyzed using a mixed-model ANOVA. The proportion of subjects who self-selected intensities above 50% VO2R was tested using a chi-squared analysis. Results: The ANOVA revealed no significant main effects or interaction. The chi-squared analysis revealed that a significant (p<0.05) proportion of subjects (28 of 33) self-selected exercise intensities above 50% VO2R. Conclusions: In the current investigation, the THE INDEPENDENT EFFECT OF SELF-SELECTED VERSUS IMPOSED EXERCISE INTENSITY ON AFFECT Luke Haile, Ph. D. University of Pittsburgh, 2010 5 affective response to SS and IMP exercise intensities of the same physical stimuli was similar, although there was a considerable amount of inter-individual variability. However, it was found that most subjects self-selected exercise intensities above a level determined by the American College of Sports Medicine to elicit health-fitness benefits. The prescription of SS exercise may be appropriate for young, recreationally active adult males.

Insulin resistance (IR) is the hallmark of type 2 diabetes (T2DM) and can precede its onset for many years. Since the prevalence of T2DM is higher among older adults, it has been suggested that aging is associated with IR. While some studies support the concept of age-related IR, others support the hypothesis that IR may not be associated with aging but rather with lifestyle patterns linked with aging, such as physical inactivity and obesity. To determine the effects of older age on IR independently of physical inactivity and obesity, we compared 7 older and 7 younger normal weight sedentary volunteers matched by gender, body mass index (BMI) and physical inactivity. In normal weight sedentary subjects, i.e., after accounting for both obesity and level of chronic physical activity, aging per se was not associated with IR. To determine the effects of obesity on IR independently of age and physical inactivity, we compared 7 older normal weight sedentary subjects to 14 obese sedentary subjects matched by age, gender and physical inactivity. After accounting for both age and physical inactivity, obesity was associated with both peripheral and hepatic IR. To determine the effects of chronic exercise on IR independently of age and obesity, we compared 14 older endurance trained athletes to 7 normal weight sedentary subjects matched by age and BMI. Within subjects of similar age and body weight, and after adjusting for body fat, higher physical activity was associated with greater peripheral insulin sensitivity, but not with greater hepatic insulin sensitivity. Intramyocellular lipids (IMCL) and fatty acid metabolites such as diacylglycerols (DAG) and ceramides (Cer) may play an important role in the pathophysiology of IR. We demonstrated that intramyocellular triglycerides (IMTG) were higher but ceramide content was lower in athletes. Moreover, the distribution of DAG and ceramide species was different in athletes compared to obese sedentary subjects. In conclusion, these data indicate that IR is not associated with age per se but rather is determined by obesity and physical activity. This study further elucidates the association among intramyocellular lipid content, aging obesity, physical activity and IR.

The role of exercise on short-term appetite regulation is not known. Furthermore mechanisms mediating this relationship need to be established. Purpose: The purpose of this study was to examine how a single bout of exercise influenced energy intake, subjective feelings of hunger, GLP-1 and acylated ghrelin concentrations compared to an exercise condition. Methods: A total of 19 overweight/obese women (BMI: 32.5 +/- 4.3 kg/m2; age 28.5 +/- 8.3 years) underwent two experimental testing sessions (exercise and rest) which were separated by at least 2 days. For the exercise session, subjects walked on a treadmill at a moderate intensity (70-75% of age-predicted maximal heart rate) until an energy expenditure of 3.0 kcals/kg of body weight was achieved. During the resting condition, subjects rested quietly for a similar length of time. Blood was drawn prior to exercise/rest, immediately post-exercise/rest, 30-minutes post, 60-minutes post, and 120-minutes post-exercise/rest and was analyzed for acylated ghrelin and GLP-1 concentrations. Subjective feelings of hunger were measured using a Likert scale prior to each blood draw. From 1-2 hours post-exercise subjects were provided ad-libitum access to a buffet-style meal and energy intake was calculated based upon food intake during this period. Results: There was no difference in energy intake between conditions (exercise: 551.5 +/- 245.1 vs. rest: 548.7 +/- 286.9 kcals). However, relative energy intake, taking into account the energy cost of exercise, was significantly lower in the exercise condition (197.8 +/- 256.5 kcals) compared to the resting condition (504.3 +/- 290.1 kcals; p<0.001). Exercise did not significantly alter acylated ghrelin, GLP-1, or subjective feelings of hunger from pre-testing to post-testing, nor were differences observed between conditions across the entire experimental testing session (p>0.05). Conclusion: Exercise does not appear to acutely influence energy intake in an overweight/obese population, thus making it a valuable component for managing body weight. Future studies should explore potential physiological or psychological mechanisms to explain why energy intake is not increased following a bout of moderate-intensity exercise in this population.

Obesity has a negative impact on physical function; however, little is known about limitations in physical function across BMI categories using both self-report and performance-based measures. Furthermore, the impact of BMI on the measurement of function has not been explored. PURPOSE: To assess physical function in adult women across BMI categories using self-report and performance-based measures and determine the influence of BMI on the relation of self-report and performance-based measures. METHODS: 50 sedentary females (10 in each BMI category: normal weight, overweight, and class 1, 2, and 3 obese) aged 51.2 ± 5.4 years participated. Assessments included demographics, past medical history, physical activity level, BMI, waist circumference, body composition, and self-report and performance-based measures of physical function. Correlation coefficients were computed between BMI and the measures of physical function. Physical function was compared between BMI categories using analysis of variance. The influence of BMI on the relation of self-report and performance-based measures was analyzed by computing correlation coefficients between the measures for the non-obese and obese and by using linear regression. Furthermore, questions from the self-report measure were compared to similar tasks on the performance-based measure for the non-obese and the obese. RESULTS: As BMI increased, physical function decreased on self-report and performance-based measures (all p <.01). Compared to those that were normal weight and overweight, the obese had poorer physical function on both types of measures (all p < .01). A large percentage of participants in the obese groups reported changes in how or how often they performed functional activities. While the performance-based and self-report measures of function were moderately correlated in the sample (p < .001), the association between the measures was significantly stronger for the non-obese compared to the obese. Compared to the non-obese, a greater number of individuals with obesity performed differently on walking tests compared to their report. CONCLUSIONS: High BMI had an adverse effect on common every-day functional tasks in adult women. Compared to those that are normal weight and overweight, individuals with obesity had the greatest impairments in physical function and tended to less accurately depict physical function abilities.

Purpose: The purpose of the study was to determine if measured maximal heart rate (HRmax) was affected by gender or aerobic training status, as well as to determine the accuracy of three common clinical maximal heart rate regression equations (MHREs) used to predict HRmax: HRmax = 220 - age, HRmax = 226 - age, & HRmax = 208 - (0.7 * age). Methods: Fifty-two aerobically active males (N=15) and females (N=15), and sedentary males (N=9) and females (N=13) within an age range of 18-25 years and with a normal BMI (18.5-24.9 kg*m⁻²) underwent a Bruce maximal treadmill exercise protocol. Heart rate, oxygen consumption (VO₂), and respiratory exchange ratio (RER) were measured. The effect of gender and training status on HRmax was analyzed through a two-way ANOVA, and the effect of gender, aerobic training status, and regression equation on accuracy of the HRmax prediction was assessed with a three-way ANOVA (&#x3B1;=0.05). The dependent variables for the three-way ANOVA included both signed residuals (observed HRmax - predicted HRmax) and unsigned residuals [absolute value of (observed HRmax - predicted HRmax)]. Results: Males and sedentary individuals had higher measured HRmax (p<.001 and p=.002, respectively) than females and active individuals. The prediction equation HRmax = 208 - (0.7 * age) had the lowest marginal error under the signed residuals (p = 0.000). When looking at the unsigned residuals, the best overall equation, equation for females, and equation for the active under the unsigned residuals was HRmax = 208 - (0.7 * age) (p = 0.000). However, the best equation for males and those that are sedentary under the unsigned residuals was HRmax = 220 - age. Conclusion: Despite small differences, HRmax = 208 - (0.7 * age) was the best overall equation to use for the greatest accuracy.

Fire suppression and rescue is a physiologically demanding occupation due to extreme external heat as well as the additional physical and thermal burden of the protective garments. The hot environment challenges body temperature homeostasis inducing heat stress. Accurate field assessment of hyperthermia is complex and unreliable. Purpose: The present investigation developed a perceptually based hyperthermia metric to measure physiologic exertional heat strain during treadmill exercise. Methods: Sixty-five (28.88 ± 6.75 yrs) female (n=11) and male (n=54) firefighters and non-firefighting volunteers participated in four related thermal stress investigations performing treadmill exercise while wearing thermal protective clothing in a heated room. Physiological and perceptual responses (i.e. body core temperature, perceived exertion, and thermal sensation) were assessed at baseline, 20-mins exercise, and at termination. Results: Perceived exertion increased from baseline (0.24 ± 0.42) to termination (7.43 ± 1.86). Thermal sensation increased from baseline (1.78 ± 0.77) to termination (4.50 ± 0.68). Perceived exertion and thermal sensation were measured concurrently with body core temperature to develop a two-dimensional graphical representation of three colored exertional heat strain zones. Each exertional heat strain zone was representative of a range of mean body core temperature responses such that green incorporated 36.0 to 37.4°C, yellow incorporated 37.5 to 37.9°C, and red incorporated 38.0 to greater than 40.5°C. Conclusions: A perceptual hyperthermia index (PHI) was developed using ratings of perceived exertion and thermal sensation. The PHI can provide a quick and easy momentary assessment of the level of risk for exertional heat strain for firefighters engaged in fire suppression and rescue. This metric may be beneficial in high risk environments that threaten the lives of firefighters.

PURPOSE: To develop and validate a modified OMNI Rating of Perceived Exertion (RPE) scale for use during bench stepping exercise (OMNI-BS); and to examine the reliability of this scale. METHODS: Thirty females (age: 19.8±1.8yrs) undertook two experimental trials, separated by 7 days. Concurrent validity was established by examining the relation between the physiological criterion variables, oxygen consumption ( O2) and heart rate (HR), with the concurrent variable, RPE from OMNI-BS, during load incremental and load intermittent trials. The load incremental test consisted of 3-min stages. During the first stage subjects stood in front of the bench (resting measurement). Subsequently subjects stepped up and down on the bench at 120 beats per minute. The test was terminated owing to subject fatigue. Exercise intensity increased as bench height increased every 3-min. The intermittent test consisted of three, 3-min, exercise bouts, that reproduced exercise stages I (low intensity), III (moderate intensity), and V (high intensity) performed in the load incremental test. The order of these three exercise bouts was counterbalanced. Test re-test reliability between trials of the OMNI-BS RPE scale was examined by comparing RPEs obtained during stages I, III, and V. RESULTS: Intraclass Correlation analysis from the load incremental and load intermittent trials indicated a strong positive association between RPE and O2 (r=0.96 and r=0.95) and HR (r=0.95 and r=0.95). Test re-test reliability also demonstrated a strong positive association of RPEs between trials (r=0.95) for the entire data set. However, separate correlation analysis conducted on each of the three stages indicated the following associations: 1) stage I: low intensity; r=0.475; p=0.009; 2) stage III: moderate intensity; r=0.559; p=0.002; and 3) stage V: high intensity; r=0.793, p<0.001. The Bland-Altman method indicated a moderate level of agreement in RPE between trials. CONCLUSION: Concurrent validity and test re-test reliability for the OMNI-BS RPE scale were established for adult females performing bench stepping exercise.

Standard behavioral weight loss programs typically result in a weight reduction of approximately 10%. These programs are generally intensive and therefore it is important to examine alternative methods, which may have the ability to enhance or produce similar outcomes. PURPOSE: To compare changes in body weight and physical activity between a technology-based system, an in-person behavioral weight loss intervention, and a combination of both over a 6-month period in overweight and obese adults. METHODS: Fifty-one subjects (Age: 44.2±8.7 years, BMI: 33.7±3.6 kg/m2) participated in a 6-month behavioral weight loss program and were randomized to one of three groups: Standard Behavioral Weight Loss (SBWL), SBWL Plus Technology-Based System (SBWL+FIT), or Technology-Based System alone (FIT). SBWL attended weekly group or individual meetings, were prescribed a diet of 1200-1800 kcal/day, and progressed from 100-300 minutes/week of moderate intensity physical activity. SBWL+FIT received the same components as SBWL plus the use of the BodyMedia FIT System that included an armband, display, and website to monitor energy expenditure and caloric intake. FIT was given the BodyMedia FIT System and received monthly telephone calls. Body weight and physical activity were assessed at 0 and 6 months. RESULTS: A total of 39 out of 51 subjects completed the 6 month assessments, with significant differences in retention rates between groups (SBWL: 53%, SBWL+FIT: 100%, and FIT: 77%) (p<0.05). Intent-to-treat analysis revealed significant weight losses at 6 months in SBWL+FIT (-8.8±5.0kg, -8.7±4.7%), SBWL (-3.7±5.7kg, -4.1±6.3%), and FIT (-5.8±6.6kg, -6.3±7.1%) (p<0.001), with a trend for greater weight loss in SBWL+FIT compared to SBWL (p=0.09). Self-report physical activity increased significantly in SBWL (473.9±800.7 kcal/week), SBWL+FIT (713.9±1278.8 kcal/week), and FIT (1066.2±1371 kcal/week) (p<0.001), with no differences between groups (p=0.25). DISCUSSION: The technology-based system used in conjunction with monthly telephone calls, produced similar, if not greater weight losses and changes in physical activity than the standard in-person behavioral program at 6 months. Furthermore, the addition of the technology system enhanced participant retention. Thus the use of this technology may reduce participant attrition as well provide an effective alternative to the standard in-person behavioral weight loss intervention.

BACKGROUD: Abdominal obesity is a strong risk factor for cardiovascular disease (CVD) and insulin resistance. Currently, the role of regular exercise alone in the treatment of abdominal obesity is unknown in adolescent boys. OBJECTIVE: The aim of this study was to examine the effect of a 3-month regular exercise alone without calorie restriction on total and abdominal adiposity in overweight adolescent boys. More specifically, the effects of different types of exercise training (aerobic vs. resistance exercise) on total fat, and visceral adipose tissue (VAT) and abdominal subcutaneous adipose tissue (ASAT) were compared. STUDY DESIGN & METHODS: Thirty overweight adolescent boys (BMI ≥ 95th percentile, 12-18 years, Tanner stage III-V) were randomly assigned to one of three intervention groups: aerobic training (AE, n = 10, 60 min/session, 3 days/week), resistance training (RE, n = 13, 60 min/session, 3 days/week) and no-exercise control group (n = 7). Outcome measurements included waist circumference (WC), total body fat, abdominal AT (VAT and ASAT), cardiorespiratory fitness (CRF) and muscular strength. RESULTS: Body weight and BMI did not change in both exercise groups (P > 0.1), but significantly (P < 0.05) increased in the control group. Compared with the control group, a significant (P < 0.05) reduction in total fat(kg) was observed in both AE (-2.3 kg) and RE groups (-1.4 kg). Both VAT (kg) and ASAT (kg) were significantly (P < 0.05) reduced in the AE (-9.7% and -6.5%, respectively) and RE groups (-14.5% and -5.2%, respectively). By contrast, both VAT (17.0%) and ASAT (6.2%) were significantly (P < 0.05) increased in the control group. Compared with the control group, a significant (P < 0.05) improvement in CRF was observed in both exercise groups, and the improvement was greater (P < 0.05) in the AE (36.5%) vs. RE (25.8%) groups. Upper and lower body muscular strength were significantly (P < 0.01) increased in the RE group (> 30% and 43-50%, respectively) compared with the AE and control groups. CONCLUSIONS: Regular exercise without calorie restriction, independent of exercise modality, is associated with significant reductions in total and abdominal adiposity and improvements in CRF and muscular strength in previously sedentary overweight adolescent boys.

PURPOSE: The purpose of this investigation was to examine the effect of knowledge of exercise duration on predicted, actual, and session ratings of leg muscle pain (RMP-Legs) during cycle ergometry. METHODS: Subjects were 36 females and 36 males, ages 18-30 yrs. Each subject performed one baseline graded exercise test to exhaustion and one isotime (20 minute) cycle trial at 70% VO2peak. Based on random assignment, the subject was told they would exercise for one of the following durations: a 20 minute trial (Accurate Duration; ACC-20), a 30 minute trial (Long Duration; LONG-30), or a 10 minute trial (Short Duration; SHORT-10). A predicted RMP-Legs was reported immediately prior to exercise. Actual RMP-Legs were reported at two min intervals during exercise. Session RMP-Legs was reported 10 min post-exercise. RESULTS: For the female sample, no differences were found in predicted RMP-Legs between knowledge of duration conditions. The interaction effect was significant. Actual RMP-Legs were higher in the SHORT-10 than LONG-30 condition at minutes 2, 4 and 6. Actual RMP-Legs were lower in the SHORT-10 than ACC-20 condition at minutes 14, 16, 18, and 20. Actual RMP-Legs were lower in the LONG-30 than the ACC-20 condition at minutes 4 and 20. Compared to the predicted RMP-Legs, actual RMP-Legs for the ACC-20 condition were lower at minutes 2, 4, and 6. Actual RMP-Legs for the LONG-30 condition were lower at minutes 2, 4, 6, 8, 10, and 12 compared to the predicted rating. Actual RMP-Legs for the SHORT-10 condition were lower at minutes 2, 12, 14, 16, 18, and 20 compared to the predicted rating. Session RMP-Legs did not differ. For the male sample, actual RMP-Legs were lower at minutes 2 and 4 compared to the predicted rating. There was no significant difference in RMP-Legs between conditions. Session RMP-Legs did not differ between knowledge of duration conditions. CONCLUSIONS: In general, pre-participation knowledge of exercise duration did not have an effect on predicted, actual, and session RMP-Legs for young recreationally active females and males. Future research should examine knowledge of exercise intensity as a possible teleoanticipatory factor that influences leg muscle pain responses during prolonged exercise.