摘要:

This study was designed to assess the contribution of the intraindividual variability of oxygen debt (O2debt) to the range (β5–248 ml/kg) reported for human subjects following exercise which required maximal oxygen uptake (max&OV0312;O2). On 5–7 occasions 6 physical education students exercised at three progressive continuous workloads on a treadmill for 15–19 minutes and the O2debt measured. Similarly 5 ice hockey forwards, 5 cross-country skiers, 5 track runners and 5 non-athletic control subjects were tested on one occasion. In every case the final exercise elicited a heart rate > 180 beats/min. and a plasma lactate > 70 mg/100 ml. The mean max&OV0312;O2and O2debts for the physical education students ranged from 51.9–68.0 ml/kg·min and 81.7–178.3 ml/kg respectively; the smallest O2debt recorded was 43 ml/kg and the largest was 228.9 ml/kg. The intraindividual variability for O2debt was greater than that for max&OV0312;O2(p < 0.01), the mean individual coefficients of variation being 21.3 and 9.0% respectively. The cross-country skiers and track runners demonstrated greater max&OV0312;O2values (p < 0.05) than the control group, but no significant difference could be shown between any of the groups for O2debt. Thus training did not appear to be a major factor contributing to the wide diversity seen in O2debts.The variability of the data clearly demonstrates that extreme caution must be exercised in the interpretation of a single measurement of O2debt, especially when studies are carried out to examine either the mechanism or magnitude of this parameter.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Key Cluster Analysis of 31 selected symptoms in the physical activity questionnaire of Kinsman et al. (9) separated the Fatigue Cluster into two components subsequently labeled General Fatigue and Leg Fatigue. Following prolonged strenuous exercise on a bicycle ergometer at 56% of estimated max&OV0312;O2, these symptom clusters increased significantly relative to initial values; they also had high coefficients of stability and testretest reliabilities. The heart rate increment from the 5th to the 13th min of effort was correlated —.41 with ride duration, .38 with Leg Fatigue, and .35 with General Fatigue. This suggests that riders of shorter duration have greater heart rate increases and larger scores for the Leg and General Fatigue components than do longer riders.Personality differences that could account for the wide range of quitting times observed at 56% max&OV0312;O2, and physiological mechanisms underlying the subjective reports of physical fatigue are discussed.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Eleven adult men were divided into a recreational games control group and an endurance running experimental group. A standard bicycle ergometer test was administered before and during the fifth, tenth, and fifteenth week of the experimental period. Pre-exercise serum creatine phosphokinase (CPK, Enzyme Commission number 2732) changed in both groups as the experimental period progressed, while pre-exercise serum glutamic oxalacetic transaminase (GOT, Enzyme Commission number 2611) levels did not change. The enzyme increases of the experimental group after four standard exercise bouts ranged from 64% to 46% for GOT and from 4% to 12% for CPK. The enzyme increases of the control group throughout the same tests ranged from 56% to 38% for GOT and from 8% to 20% for CPK. These exercise induced enzyme increases did not change throughout the experimental period. Heart rates during and after the standard exercise, especially in the endurance running group, decreased throughout the experimental period.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Early studies of subjective force estimates for short-time work on a bicycle ergometer are reviewed. Results showed that perceived pedal resistance followed a positively accelerating function with an exponent of 1.6. A model for inter-individunl comparisons using subjective range as a frame of reference is explained. Results of two experiments comparing four different rating methods are reported. Two methods involved the original Borg Senle, and a variation, one graded from 1 to 21 and the other from 6 to 20. The third method utilized a line scale while the fourth scale was graded from 1 to 9 with 2 anchored by the expression “Not At All Stressful” and 8 with “Very, Very Stressful.” These two experiments show that good correlations between heart rates and ratings are obtained independently of which scale is used. Since the Borg (6 to 20) Scale is the one most often used and gives values that grow fairly linear with work load and heart rate it is proposed that this scale be used in most cases.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

In order to test the validity of Borg's rating scale of perceived exertion, 8 lean and 8 obese subjects participated in a study to determine whether they could perceive small differences in work intensity when the work loads were presented in a random order. These results were compared with those obtained during the progressive exercise test normally used with this scale. Reliability was determined by testing each subject twice with each protocol. The testing order of the 2 protocols and also the order of work loads used during the random test were assigned using a Latin square design.There were no significant differences in any of the physiological and perceptual variables between the 2 types of test protocols. Coefficients of reliability for both procedures were high. Consequently, the progressive test is recommended for use since it is less time-consuming.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

A series of experiments involving the interaction of perceived exertion, selected psychological states and traits, and metabolic responsivity to bicycle ergometry are reviewed. The findings indicate that normal subjects are capable of consistently identifying differences in work load by means of Borg's psychophysical category scale, and these subjective estimates mirror the actual metabolic cost of the work being performed. The exception to this generalization is the case where the subject is neurotic, anxious or depressed since such individuals appear to have difficulty in their perceptual processing of work intensity. Extroverts tend to underate work intensity at heavier loads, and their stated work preference is higher for prolonged work than it is for introverted subjects. Pre-exercise self reports of somatic perception correlated with perceived exertion across a 30-minute work bout. Various psychological states and traits seem to play a role in the perceptual processing of information relating to muscular work, and both metabolic and perceptual responsivity of exercising subjects has been manipulated by means of hypnotic suggestion. It is concluded that a psychobiologic approach to perceived exertion is the most efficacious.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

The general purpose of the investigation was to identify some of those physiological parameters, taken individunlly and collectively, which account for the greatest variability in perceived exertion (RPE) responses during thirty minutes of bicycle ergometer exercise. The data from eight independent variables recorded at 5, 15 and 30 minutes during two conditions were submitted to forward selection multiple regression analyses. Six male students between the ages of 18 and 22 years rode during five trials. Three trials were performed under a neutral temperature condition (24°C) at 48, 60 and 68% of max&OV0312;O2. Two trials were performed under hot temperature conditions (44° and 54°C) at 48% of max&OV0312;O2. Ventilation (&OV0312;E) accounted for the greatest variance in RPE at 5 and 15 minutes and respiratory rate (RR) made the greatest contribution at 30 minutes in both conditions. The independent variables accounted for more total variance in the heat at each time point (84, 84 and 77%) than in the neutral (66, 80 and 53%), Rectal and skin temperature (Trand Ts) appear sooner and account for more variance in RPE in the heat than in the neutral environment. It was hypothesized that man does not directly attend to physiological processes, per se, as a basis for perceived exertion ratings but does attend to the externalization of these processes, i.e., increases in metabolic rate result in increases in &OV0312;E, RR and Tswhich can be directly perceived.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

Perception of exertion (RPE) during exercise was studied in 8 lean and 8 obese young men. Each subject was tested twice to maximum (a) at 24°C on a bicycle ergometer, treadmill with and without excess weight (lean subjects were weighted to match the percent excess weight of obese subjects) and (b) at 32°C on the treadmill with and without excess weight. Oxygen intake (Vo2), ventilation (VE), heart rate (HR) and RPE were determined at each work load.No significant differences in RPE vs Vo2were observed on the treadmill. Lean subjects reported higher RPE's on the bicycle than did obese subjects. All subjects rated the bicycle to be harder than the treadmill at the same Vo2. Excess weight did not affect RPE vs Vo2in lean subjects. Obese subjects were not affected by the 32°C environment, while lean subjects rated higher at the same Vo2. RPE vs HR was unchanged under all conditions. Although there were differences between lean and obese subjects when RPE was related to absolute values of VEand Vo2, relative to maximal values there was no difference. Since the maximal HR was similar, there was no difference in RPE vs HR on an absolute or relative basis. RPE appears to be most closely related to the proportion of maximal capacity required for a given work load.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID

摘要:

It was hypothesized that perceptions of exertion while running would be greater than for walking at velocities lower than approximately 4.0 mph. The reverse was hypothesized at velocities higher than approximately 4.0 mph. Twenty male university students served as subjects. Utilizing a motor-driven treadmill, subjects walked and ran at each of four randomly presented velocities, i.e., 2.5, 3.5, 4.5 and 5.5 mph. Heart rate and perceived exertion were recorded during the last 30 seconds of each 3 minute velocity trial. Heart rates while walking were found to be less than for running at velocities less than 4.0 mph. The curves intersected at 4.92 mph and reversed so that walking heart rates were higher following this point. Perceived exertion displayed a similar pattern except the curves intersected at a significantly lower velocity, i.e., 4.31 mph. Although perceived exertion generally follows heart rate responses, local muscular discomfort at higher walking velocities is proposed as the factor responsible for the earlier perceptual intersection.

ISSN:0025-7990    

出版商:OVID    

年代:1973

数据来源: OVID