Effects of a Learning Trial on Self-Regulation of Exercise

Heart rate (HR) and ratings of perceived exertion (RPE) are common exercise intensity regulatory strategies, however, some individuals are unable to use these strategies effectively. Alternative or conjunctive strategies may aid in the transition to self-guided programs. The purpose of the present study was to examine the value of a brief, field-based exercise intensity learning trial on self-regulation of intensity during a weeklong exercise program. Forty-two males were randomly assigned to either a paced learning trial (P) or non-paced control (NP), and then one of three intensity feedback groups: HR, HR + RPE, or no feedback (CONT). The paced trial consisted of an 800-m trial at 75 % of maximal heart rate reserve (MHRR) on day one. Subjects then completed four 800-m trials each day for four days and received feedback on deviation from target HR (THR) after each 800-m trial. Four-way MANOVA (pacing x feedback x trials x days) was used to assess the influence of the learning trial on THR deviation scores across the week. The pacing x feedback x trials interaction was significant (Pillai's Trace = 0.36, approximately F (6,70) = 2.56, p = 0.03) and thus, the influence of the learning trial was assessed within feedback group. There were no significant differences in THR deviation scores for P vs. NP within the HR or HR + RPE feedback groups. However, P was significantly more accurate then NP (p < 0.05) within the CONT feedback groups during each trial averaged across the week (T (1) = - 2.6 vs. 5.3; T (2) = 2.6 vs. 14.2; T (3) = 4.6 vs. 16.2; T (4) = 5.3 vs. 20.5 beats . min (-1)). These results demonstrate that a brief intensity learning trial, in the absence of HR or HR+RPE feedback, provided for accurate self-regulation of vigorous exercise training. These results would support the efficacy of a brief intensity learning trial within the context of transitioning an individual to a self-guided exercise program.

The effects of blood lactate concentration on perception of effort during graded and steady state treadmill exercise

Studies have reported that ratings of perceived exertion (RPE) are a valid tool for exercise prescription when blood lactate concentration (BLC) is used as the intensity criterion. However, few have studied the relationship between RPE and BLC during commonly used graded exercise tests (GXTs) and simulated exercise training. The purpose of this study was to determine if the RPE: BLC relationship is transferable across GXTs and a steady state exercise trial (SST). Thirteen healthy males (25+/-5.3yrs) completed two maximal treadmill tests (Bruce and Balke protocols) followed by a SST which consisted of approximately 8 minutes of exercise at each of two intensities (approximately 40% and 70% maximal heart rate reserve). BLCs and other physiological measures were compared at matched RPEs across the GXTs and SST trial at each exercise intensity using a two-way repeated measures ANOVA. There were no significant differences in BLC at a matched RPE across the exercise trials at the lower exercise intensity with the BLCs being 1.5+/-0.3, 1.6+/-0.6 and 1.3+/-0.3 mM, respectively. However, at the higher exercise intensity BLCs were significantly lower during the Balke GXT compared to the Bruce GXT and SST (1.8+/-0.6, 2.8+/-1.8 and 3.0+/-0.8 mM, p < 0.05). These results suggest that the RPE: BLC relationship may be protocol dependent during graded exercise testing as it was only transferable from the Bruce GXT to the exercise training setting at intensities in the typical prescription range of 50-85% of VO2max.

Physical fitness and clustering of risk factors associated with the metabolic syndrome

PURPOSE

The purposes of this study were to 1) assess the prevalence of clustering of metabolic markers of the MS in a defined population and 2) determine the association between CRF and such clustering in a large group of adult men (N = 15,537) and women (N = 3,899).

METHODS

Metabolic markers of the MS included systolic blood pressure (BP) > or = 140 mm Hg, serum triglycerides > or = 150 mg x dL(-1), fasting blood glucose > or = 110 mg x dL(-1), and elevated central adiposity (waist circumference > 100 cm). Cardiorespiratory fitness was defined as total time on a maximal treadmill exercise test. The cohort was grouped by the number of metabolic abnormalities and level of CRF. Associations between CRF and the number of metabolic abnormalities were assessed using proportional odds logit models.

RESULTS

Among men, the age-adjusted cumulative odds ratio for abnormal markers of the MS was 3.0 (95% C.I. 2.7-3.4; P < 0.001) for the least-fit men when compared with moderately-fit ones, and 10.1 (95% C.I. 9.1-11.2; P < 0.001) when compared with the most-fit men. Among women, the age-adjusted cumulative odds ratio was 2.7 (95% C.I. 2.1-3.5; P < 0.001) for the least-fit women when compared with moderately-fit ones, and 4.9 (95% C.I. 3.8-6.3; P < 0.001) when compared with the most-fit women.

CONCLUSIONS

These cross-sectional results suggest that low CRF is associated with an increased clustering of the metabolic abnormalities associated with the MS in both adult men and women and support the need for future prospective analyses.

Evaluation of a new standardized ramp protocol: the BSU/Bruce Ramp protocol

BACKGROUND

Because of recent technological advances, exercise testing laboratories now have the ability to use ramp protocols with treadmill exercise tests. Since the Bruce protocol is the most widely used treadmill protocol in clinical laboratories, a standardized ramp treadmill protocol was developed that corresponds to the speed and grade settings of the Bruce protocol at each 3-minute time interval. The purpose of this study was to evaluate the utility of using subject demographic and exercise test data to predict peak oxygen uptake (VO2peak) for tests conducted with the BSU/Bruce Ramp protocol.

METHODS

Maximal exercise tests were performed by 698 men and women using the BSU/Bruce Ramp protocol. Peak oxygen uptake was measured during all tests. Stepwise multiple regression analyses were used to predict VO2peak (mL.kg-1.min-1) from maximal treadmill test time and selected variables including age, gender, physical activity habits, and body weight.

RESULTS

Maximal test time was found to be the most potent predictor of VO2peak, accounting for 86% of the variance in peak aerobic power, with a standard error of estimate of 3.4 mL kg min-1. A multiple regression equation including age, gender, physical activity habits, and body weight resulted in a slightly improved prediction (R2 = 0.88; standard error of estimates = 3.1 mL kg min-1).

CONCLUSIONS

Peak oxygen uptake values can be predicted with reasonable accuracy from the BSU/Bruce Ramp protocol. The BSU/Bruce Ramp would be an excellent choice for laboratories desiring to use a ramp treadmill protocol because of the design of the protocol with identical workloads at equivalent time periods (3, 6, 9, 12, 15, 18, 21 minutes) as the commonly used Bruce protocol.

Caffeine consumption habits do not influence the exercise blood pressure response following caffeine ingestion

BACKGROUND

The purpose of this study was to determine if the BP response during walking following caffeine ingestion differed between those who regularly consume caffeine and those who do not.

METHODS

A double-blind cross-over experimental design was used. Data were collected in a research laboratory with a clinical exercise testing room. Eight regular caffeine users and eight men who did not habitually consume caffeine were studied. Each subject consumed of a beverage once with and once without 4.5 mg caffeine/kg fat-free mass added to the drink. Following consumption each subject walked at three intensities of exercise (30, 50, and 70% of VO2peak). Measures of BP were obtained by the auscultatory technique.

RESULTS

Caffeine consumption resulted in significant increases in both systolic BP and diastolic BP at rest and during exercise. The elevation during exercise was 7-8 mmHg at all three exercise intensities for systolic BP; however, for diastolic BP there was only a significant elevation (4 mmHg) at the highest exercise intensity. No differences were noted between those men who regularly consume and those who regularly abstain from caffeine. There was a wide range in the resting BP response to caffeine (combined SBP and DBP ranged from 10-39 mmHg) suggesting that there are marked differences in sensitivity to caffeine, irrespective of individuals' consumption habits.

CONCLUSIONS

Consideration should be given to caffeine intake prior to exercise in patients for whom an additional increase in BP during exercise would not be desirable.

Evaluation of lipid profile measurements obtained from the Cholestech L.D.X analyzer

BACKGROUND

The Cholestech L.D.X analyzer has the capability of performing a lipid profile in approximately 5 minutes. The purpose of this study was to determine analytical performance capability of the L.D.X to perform lipid profile measurements.

METHODS

Forty subjects gave two finger capillary samples and one venous serum which were analyzed in duplicate by two technicians, on two different L.D.X analyzers. A local pathology laboratory was used as the standard for accuracy comparisons. Two controls with known values were provided by the manufacturer to assess within-day precision. Day-to-day precision was determined by analyzing high (240 mg/dL-1 total cholesterol (TC) and 60 mg/dL-1 high-density lipoprotein [HDL]) and low (200 mg/dL-1 TC and 35 mg/dL-1 HDL) human serum samples on 10 different days.

RESULTS

Analysis of variance procedures revealed no significant differences between the two technicians or the two analyzers, nor among the fingerstick, venous serum, or reference measures for any of the analytes. The total error of measurement of TC, triglycerides, and HDL measurements were 6.3 to 16.2%, 14.8 to 30.8%, and 11.5 to 26.8%, respectively. In comparison to the National Cholesterol Education Program (NCEP) desirable, borderline-high, and high classifications obtained from the reference laboratory the L.D.X TC results were correctly classified in 92.5% of the cases. L.D.X triglyceride classifications of desirable, borderline hypertyglyceridemia, and distinct hypertriglyceridemia matched 100% with the classifications obtained from the reference laboratory.

CONCLUSIONS

Although the Cholestech L.D.X analyzer did not consistently meet NCEP standards for acceptable total measurement error of TC, HDL, and triglyceride analyses, it seems capable of providing reasonable lipid profile measures in both a screening setting and a clinician office where the goal is correct classification of patients' results.

Validity of rating of perceived exertion during graded exercise testing in apparently healthy adults and cardiac patients

PURPOSE

Recent exercise guidelines recommend a generalized rating of perceived exertion (RPE) range of 12 to 16 (15-point Borg scale) as the perceptual range associated with a physiological training effect. However, whether an individual who selects an RPE within the generalized range during an graded exercise test or exercise training, is actually within the correlated physiological range (50 to 85% maximum oxygen consumption [VO2max]) has not been studied in large samples of apparently healthy individuals or cardiac patients. The purpose of the present study was to assess the validity of the generalized RPE recommendations in a large heterogeneous group of apparently healthy subjects and cardiac patients.

METHODS

Subjects included apparently healthy adults (N = 463) and cardiac patients (N = 217) who presented for a sign-symptom limited maximal graded exercise test (SSLMGXT). Ratings of perceived exertion associated with relative exercise intensities of 60 and 80% of maximal heart rate reserve (MHRR) and peak exercise were selected for analyses.

RESULTS

Significant interindividual variability in RPE was observed at both relative exercise intensities (6 to 20 RPE range at 60% MHRR; 8 to 20 RPE range at 80% MHRR) for both populations. Thirty-nine percent of healthy subjects and 32% of cardiac patients reported an RPE outside an 11 to 14 range at 60% of MHRR, whereas 32% of healthy subjects and 52% of cardiac patients reported an RPE outside of a 14 to 17 range at 80% of MHRR. Peak RPE was higher for the apparently healthy subjects compared with the cardiac patients (18.8 +/- 1.2 versus 16.5 +/- 1.8; P < 0.01).

CONCLUSIONS

These results challenge the applicability of the generalized RPE recommendations described in recent exercise guidelines under typical clinical exercise testing conditions. The basis for the generalized RPE recommendations warrant further investigation. Those who desire to use RPE as a marker of relative exercise intensity during SSLMGXT should take into consideration the large interindividual variability in these measures.

Reliability of perceived exertion during graded exercise testing in apparently healthy adults

PURPOSE

Ratings of perceived exertion (RPE) are widely used for monitoring individuals during graded exercise testing. Studies of the reliability of RPEs across various exercise conditions have produced mixed results. The purpose of this study was to assess the reliability of RPEs during graded exercise testing by comparing the perceptual-physiological relationship between the Bruce and Balke treadmill protocols throughout a broad range of relative exercise intensities.

METHODS

Thirty-eight middle-aged men and women completed two maximal treadmill graded exercise testing separated by 48 hours. Test order was randomly assigned. RPEs were compared across protocols and between gender at selected exercise intensities using a series of two-way analysis of variances with repeated measures.

RESULTS

A comparison of RPEs (Borg 15-point scale) during the graded exercise testing revealed significant protocol and gender differences at 40%, 60% and 80% of maximal heart rate reserve. RPEs were significantly higher during the Balke protocol compared to the Bruce at each intensity (45% = 9.5 +/- 2.0 vs. 8.3 +/- 1.6; 60% = 12.7 +/- 2.4 vs. 11.1 +/- 2.3; 80% = 15.7 +/- 2.2 vs. 14.1 +/- 2.0). In addition, men rated each intensity significantly higher than the women (P < 0.05).

CONCLUSIONS

The results from the present study confirm that the perceptual-physiological relationship observed during graded exercise testing varies as a function of the treadmill protocol employed and that these differences extend throughout the exercise training intensity range (40--80% of maximal heart rate reserve) recommended for healthy adults. The perceptual differences between the protocols could not be accounted for by any of the physiological measures assessed within the study. These results have implications when using RPEs from exercise testing for exercise prescription purposes.

Postprandial lipemia in obese men with abdominal fat patterning

OBJECTIVE

The purpose of this study was to assess differences in measures of postprandial triglyceride (TG) clearance between obese men with abdominal fat patterning (OAF) and men of desirable weight (DW). It was hypothesized that the OAF men would have impaired postprandial TG clearance.

EXPERIMENTAL DESIGN

A comparative design was used.

SETTING

Data were collected in a research laboratory with access to blood analysis instrumentation.

PARTICIPANTS

Fourteen healthy, physically active, normolipemic men (7 OAF and 7 DW) were studied.

INTERVENTIONS

Each subject consumed an oral fat load (78 grams of fat) and blood samples were collected every hour for 8 hours.

MEASURES

Measures of postprandial lipemia included: incremental TG area, total TG area, time to peak TG concentration, maximal change in TG concentration, and time to return to baseline TG concentration.

RESULTS

OAF men had significantly greater total area under the TG curve (24.7 +/- 1.09 vs 16.1 +/- 1.3 mmol-L(-1).8 hours, p = 0.003) and greater maximum TG change (2.0 +/- 0.3 vs 1.2 +/- 0.2 mmol-L-1, p = 0.03) following the oral fat load. Additionally, the total area under the TG curve was positively correlated with baseline TG concentrations (r = 0.53) and inversely correlated with baseline HDL2 concentrations (r = 0.64). Baseline HDL2 concentrations were inversely correlated with time to return to TG baseline (r = 0.57).

CONCLUSIONS

Normal fasting lipoprotein profiles and regular physical activity do not preclude OAF men from having pronounced postprandial lipemia.

Evaluation of the ACSM submaximal ergometer test for estimating VO2max

The purpose of this investigation was to assess the reliability and validity of maximal oxygen uptake estimates (ESTmax) from the ACSM submaximal cycle ergometer test. Subjects included 15 men and 15 women aged 21-54 yr who performed two submaximal tests and one maximal cycle ergometer test to determine maximal oxygen uptake (VO2max). During the submaximal tests, heart rates (HR) were recorded from a radio telemetry monitor. ESTmax was predicted for both submaximal trials by extrapolating HR to an age-predicted maximal HR. Correlation coefficient and standard error of measure (SEmeas) for ESTmax between submaximal trials were r = 0.863 and SEmeas = 0.40 l.min-1, while a t-test revealed no significant difference between trials. Although trial means were not significantly different, large variation in individual cases was evident by the high SEmeas (0.40 l.min-1) and by a large SEmeas expressed as a percentage of the mean (13%). The mean of the two ESTmax significantly overestimated measured VO2max with percent error, total error, and mean error equal to 25.7%, 0.89 l.min-1, and 0.63 l.min-1, respectively. The standard error of estimate expressed as a percentage of the mean was equal to 16% and 15% for both ESTmax. In summary, the ACSM protocol failed to be reliable as represented by the large differences found between submaximal trials. Furthermore, the protocol significantly overestimates VO2max and should not be used when an accurate assessment of VO2max is required.

Epidemiology of physical activity, physical fitness and coronary heart disease

Observational population-based studies have consistently shown an inverse dose-response gradient between physical activity or fitness and coronary heart disease. This relationship is more firmly established in men. Existing studies suggest that the physical activity gradient, and perhaps the fitness gradient, is produced by a combination of varying levels of both the intensity and the amount of habitual physical activity. It is not at present possible to definitively describe the dose-response association between the intensity of physical activity and the risk of coronary heart disease. An answer to this important question awaits further research.

Failure of predicted VO2peak to discriminate physical fitness in epidemiological studies

Previous investigators reported that peak oxygen uptake (VO2peak) could be accurately predicted from nonexercise test variables, and that this score would be suitable for categorizing cardiorespiratory fitness (CRF) within epidemiological studies. However, the accuracy of these models has varied considerably. The purposes of this study were: 1) assess the accuracy of predicting VO2peak with a new nonexercise model, and 2) assess the utility of the predicted VO2peak for categorizing CRF in epidemiological studies. Subjects included 2,350 men and women. Cross-validated multiple regression models revealed that age, sex, resting heart rate, body weight, percentage body fat, smoking, and physical activity were significant predictors (P < 0.001) of VO2peak. The multiple regression model for relative VO2peak (ml.kg-1.min-1) had R2 = 0.733 (SEE = 5.38), whereas the model for absolute VO2peak (l.min-1) had R2 = 0.773 (SEE = 0.425). The 95% confidence intervals for the predicted VO2peak were large (+/- 10.6 ml.kg-1.min-1 and +/- 0.833 l.min-1). These results support the notion that VO2peak can be predicted from a multiple regression model devoid of exercise test variables. However, due to the extreme variability in the predicted scores, the regression models were unable to effectively distinguish CRF categories. Therefore, despite statistical success in predicting VO2peak for the nonexercise test regression models, we conclude that such models fail to provide the accuracy needed for categorizing CRF within large epidemiological cohorts where the purpose is to assess mortality risk.

Influence of metabolic control on the ventilatory threshold in adults with non insulin-dependent diabetes mellitus

Metabolic control, as assessed by glycosylated hemoglobin (HbA1c), has been reported to have a relationship to various submaximal exercise responses. However, due to the narrow range of HbA1c and the limited exercise data from previous studies on individuals with diabetes, little support for the above statement exists in the literature. The current study assessed the relationship between HbA1c and submaximal, or ventilatory threshold (VT), and maximal exercise (VO2 peak) responses in subjects with non-insulin-dependent diabetes mellitus (NIDDM). Sixteen subjects (age = 56.5 +/- 14.4 yrs; Wt = 82.6 +/- 17.2 kg; B.M.I. = 29.5 +/- 2.7 kg.m-2) performed a ramp (20 watts.min-1) leg cycle ergometer test (GXT). Their HbA1c was 11.8 +/- 2.8% (range 6.5 to 16.6%). Breath by breath respiratory analysis was performed using a Med Graphics 2001 cart. Ventilatory threshold (VT) was determined using the V-slope method. The VT was 1,151 +/- 487 ml.min-1 or 70.2 +/- 10% VO2peak; VO2peak was 1,645 +/- 740 ml.min-1. There were no significant relationships found between HbA1c and the VO2 at the VT (r = 0.04), the % of VO2peak at the VT (r = 0.23), and the VO2peak (r = 0.17). In conclusion, metabolic control, as assessed by HbA1c, did not influence selected submaximal and maximal exercise responses in NIDDM. Therefore, exercise prescription for individuals with NIDDM may not need to consider the individual's HbA1c concentration as a modifier of their exercise response.

Evaluation of a shallow water running test for the estimation of peak aerobic power

The purpose of this investigation was to assess the validity of a 500-yard shallow water run test to determine peak aerobic power (VO2peak) and to compare it with the commonly used 1.5-mile run test. Subjects included 15 men and 28 women who completed two trials each of a 500-yard shallow water run test and a 1.5-mile run and then completed a graded exercise test on a treadmill to determine VO2peak. Correlation coefficients with measured VO2peak were -0.89 and -0.80 for the 1.5-mile and 500-yard water runs, respectively. Multiple regression analyses revealed that prediction of VO2peak from 1.5-mile run time was significantly improved by including the 1.5-mile run peak HR (R2 = 0.82, SEE = 3.52 ml.kg-1.min-1). Similarly, for the 500-yard water run test, percent body fat and height were significant additional predictors of VO2peak (R2 = 0.86, SEE = 3.19 ml.kg-1.min-1). We conclude that the 500-yard shallow water run test, especially when used with the descriptive measures of percent body fat and height, can provide a reasonable estimate of an individuals' cardiorespiratory fitness classification. However, caution is advised when administering these tests in older populations or in those with multiple coronary risk factors.

Differences in estimates of percent body fat using bioelectrical impedance

The purpose of the present investigation was to analyze the replicability of percent body fat (% fat) determined from Bioelectrical Impedance Analyses (BIA) after 2 different postprandial time periods and by 2 different technicians. The BIA % fat measures were also compared to those determined from skinfold measurements (SF) and hydrostatic weighing (HW). Fifteen physically active men had body composition determined on 4 separate days over a 2 week period under controlled conditions, once each week after fasting for 12 hours and once after 3 hours. Each day the subjects had BIA and SF measures taken by different trained technicians. Once each week the subjects also were hydrostatically weighed (HW). There were no differences for either BIA or SF between the 2 postprandial time periods. There were significant differences between technicians for both BIA and SF (p < 0.01), although the relationships between technicians were good (r = 0.90 and 0.95, respectively). Mean values for BIA (11.8 +/- 3.2%) and HW (11.0 +/- 7.2%) were similar, however, the correlation was only r = 0.50. These results indicate that although BIA gave relatively consistent values, it regressed both low and high % fat values towards the mean of the sample.

Predictors of over- and underachievement of age-predicted maximal heart rate

The age-predicted maximal heart rate (PMHR) formula, 220--age, is frequently used for identifying exercise training intensity, as well as determining endpoints for submaximal exercise testing. This study was designed to identify variables discriminating those with actual maximal heart rates considerably above or below that predicted from the 220--age equation. Subjects included 2010 men and women ranging in age from 14 to 77 yr. Stepwise discriminant analysis was performed using maximal heart rate error groups as the dependent variable, and selected preexercise test characteristics as predictors. The HR error groups were based on the difference between the measured and PMHR as follows: below (> or = 15 beats.min-1 below PMHR), within (+/- 14 beats.min-1 of PMHR), and above (> or = 15 beats.min-1 above PMHR). A contrast of the below and above groups identified age, resting HR, body weight, and smoking status as predictors of group membership (P < 0.01) for both men and women. The overall canonical correlation was 0.282 and 0.294 for the men and women, respectively. Older age, higher resting HR, lower weight, and non-smoking were related to the above group, while the inverse was related to the below group. Standardized coefficients suggest that age and resting heart rate for the men, and age and smoking status for the women were the most potent variables for discriminating extreme deviations between measured and PMHR.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of within-day precision of serum cholesterol measured by a portable analyzer

The use of dry-chemistry analyzers for the measurement of cholesterol in mass screening settings has received considerable attention. Less is known about the efficacy of these types of analyzers in the clinical office or laboratory setting. Thus, we investigated the within-day precision of cholesterol measurements performed by the Reflotron method with specific comparisons made between two trained technicians and two instruments. Forty serum specimens were analyzed eight times (twice by each technician on both instruments) with the identity of the specimen blinded from the technician. Each specimen was also analyzed by two different methods commonly accepted in the clinical laboratory to estimate the accuracy of the Reflotron cholesterol measures. Small, significant (P less than 0.05) main effect differences were observed in cholesterol concentrations between technicians (1.8%) and instruments (0.8%). The overall coefficient of variation (CV) of the serum cholesterol measures was 2.5%, which meets the Laboratory Standardization Panel's "ideal" goal. However, three individual cases (one specimen's eight analyses) had CV greater than 5%, and three other cases had CV greater than 3%. Most of these cases could be traced to one outlier value. Review of all 320 Reflotron analyses revealed that only 10 (3.1%) were outliers (greater than 5% from specimen mean value). When operated in a laboratory with regular quality control procedures, the Reflotron method can meet national standards for precision. In this setting, differences between technicians and instruments are not of clinical importance.

Ratings of perceived exertion among standard treadmill protocols and steady state running

The purpose of this study was to determine if differences exist in ratings of perceived exertion (RPE) at a predetermined relative heart rate between two standard treadmill protocols and steady state exercise in a field setting. Thirty healthy male (N = 15) and female (N = 15) volunteers were maximally tested using the standard Bruce and a modified Balke (3.0 mph with 2.5% grade each two minutes) protocols. Each subject was randomly assigned to one treadmill protocol first, and then completed the second test forty-eight hours later. Within forty-eight hours following the second treadmill test, all subjects completed a field exercise trial consisting of an 800-m run. During the field trial an investigator paced each subject to an individualized target heart rate (75% maximal heart rate reserve) calculated from the treadmill tests. The total exercise time for the field trial was 4:31 +/- 0:22 and 5:36 +/- 0:47 min for the males and females, respectively. During the last 50 m of the field trial, RPE values were recorded. Comparisons of the rating of perceived exertion at the target heart rate (RPE at THR) were made using a 2-way (Gender x Trials) ANOVA with repeated measures across trials. There was a significant gender x trials interaction for RPE at THR, with males reporting significantly higher values during the treadmill tests as compared to the females (BRUCE = 13.5 +/- 1.6 vs 12.2 +/- 1.8; BLAKE = 15.9 +/- 2.3 vs 13.7 +/- 2.4). There was no difference noted between genders for RPE at THR during the field trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Falls in the elderly: Part I, Gait

The aim of this study was to determine a gait profile of two groups of elderly adults: one with a history of falls and one without a history of falls. The following gait characteristics were identified: step frequency, stance time, swing time, double support time, step length, heel width, heel height, toe height, and hip, knee, and ankle angular excursion. The history of falls group was composed of 25 subjects (seven men and 18 women), and the no history of falls group was composed of 30 subjects (12 men and 18 women). Two 16-mm Locam cameras were used to film the subjects. Each subject was filmed while walking on a motorized treadmill at 4 km/h and 6 km/h. The film data were digitized on a sonic digitizer interfaced to a VAX computer. The ANOVA statistic indicated significant (p less than .05) difference between the two independent variables for heel width. There appears to be no significant relationship between the studied gait characteristics (other than heel width) and falls in apparently healthy elderly individuals.

Falls in the elderly: Part II, Balance, strength, and flexibility

The purpose of this study was to determine and compare the balance, muscular strength, and flexibility of two groups of elderly adults: one with a history of falls (HF) and one with no history of falls (NHF). Subjects were 19 men and 36 women. Static and dynamic balance was determined by a one-foot stance balance test and a backwards walking test. Hip, knee, and ankle joint muscular strength were assessed on a Cybex Leg Press Dynamometer. A goniometer was used to determine hip, knee, and ankle joint range of motion (flexibility), ANOVA indicated a significant difference between the two groups for static balance (p less than .001), leg strength (p less than .01), and hip and ankle flexibility (p less than .01). The results suggest that balance, leg strength, and flexibility may be factors contributing to falls in the elderly.