The aim of this thesis is to demonstrate the importance of walking to public health. The first part is characterized by epidemiological research. First, a typology for the measurement of walking is developed. A systematic review is conducted of observational studies to determine the health benefits of walking in its own right. Studies consistently confirm that 30 minutes walking on most days of the week is sufficient to reduce the risk of cardiovascular diseases and non-communicable disease risk. Then, a series of epidemiological analyses describes the prevalence and correlates of walking, using multiple health and non-health surveillance data sets. Surveillance data indicate that the prevalence of walking at the above recommended levels is low across all domains. Between 1991 and 2001 an increase in walking occurred, and was the main contributor to reductions in leisure time physical inactivity; however, the proportion of the population who achieved the recommended amount of physical activity by walking did not change in leisure and transport domains. The next part of the thesis is characterized by health promotion research examining the impact of three population-based approaches to increasing walking among Australian adults. The first was an evaluation of a conversion of rail to trail, as an environmental change intervention; the second was a mass media campaign promoting walking to work, and the third was a targeted print media walking program. Providing environmental supports with minimal promotion had no effect on walking. A nation-wide mass media campaign promoting walking to work increased walking and other moderate intensity physical activity, but process evaluation indicated other promotional efforts contributed as well. The targeted print media randomised trial had the greatest effect on walking, but the increases were not greater than spontaneous change in the control. Increases in total physical activity were achieved only when the intervention was supplemented by the use of a pedometer. The expectation that broader approaches to the promotion of walking will bring about changes at the population level, were not corroborated by these case studies. There is a need for enhancement of walking-specific interventions to influence total PA at the population levels.

Regular participation in sports is a common practice among the general population. For cardiovascular fitness, the frequency, duration, intensity and mode of the activity must be appropriate for the individual to benefit from the activity. The benefits for cardiovascular fitness are questionable in sports involving high intensity intermittent exercise of short duration. In the past, the procedures for determination of the heart rate and the time-motion characteristics of an activity were cumbersome and time consuming, thus making application to sports an inconvenience. The purpose of this project was to develop a computer based system for matching heart rate data with time-motion characteristics. The system was tested using ice hockey and squash. Subjects were observed during activity. The heart rate data during the activity were collected using a Polar Vantage XL Heart Rate monitor set to record heart rate values in 5-second intervals. The duration and type of activity were entered in the computer in real time using a coding system. Program combined the time-motion analysis with the heart rates that were downloaded from the Polar heart rate monitor. The results were summarized as follows: (1) total time at each intensity level, (2) mean duration at each intensity level, and (3) mean heart rate at each intensity level. Output from the computer program was similar to manual calculations.

The recent American college of Sports Medicine Position Stand concerning the quantity and quality of exercise for developing cardiovascular fitness (1) suggests a need for more information concerning the rate of improvement in aerobic power as a function of age. Therefore, the purpose of this retrospective study was to assess whether the change in maximal oxygen uptake (AVO2max) following endurance training varies as a function of age. Subjects were healthy men (N=277) and women (N=161), ranging in age from 20-72 years, who completed an endurance training program (= 3-5 months) between 1972 and 1987. The standard training stimulus consisted of individualized aerobic exercise (walking, walk-jog, or jogging) at about 75-85% maximal heart rate reserve for = 30-60 minutes, 3-4 sessions per week. A description of the %OVO2max expressed in relative and absolute terms, ± SEE are presented below.Variable20-29 yrs30-39 yrs40-49 yrs50-59 yrs60-69 yrsM 9/6AV02max ml•kg-1-min-'17.1 ± 13.220.0 ± 11.817.3 ± 13.319.5 ± 13.719.8 ± 9.1M%%OV02maxLmin-112.6 ± 10.616.0 ± 11.514.7 ± 11.616.6 ± 15.116.2 ± 9.8F °/oA VO2max mlkg''•min-'16.3 ± 9.022.5 ± 13.119.0 ± 10.917.6 ± 13.415.4 ± 6.8F%OV02maxL.min-'15.2±12.321.7±12.716.6±11.515.7±13.411.9±9.8N=Men women)20(17)87(54)112(51)46(30)12(9)A stepwise multiple regression analysis was used to assess the relationship between age and %OVO2max in both relative and absolute units, after adjusting for other parameters known to effect the training response. After adjusting for pre-training VO2max.(ml-kg-1-min-1) there was a significant negative correlation between OVO2max and age in both men (r = -0.31, p < 0.01) and women(r = -0.37, p < 0.01). When expressed as %OVO2max (L•min-1), the resultsrevealed the same age trend as that observed for the relative unit. Since the AVO2max after =3-5 months of training decreased as a function of age, this study supported the contention that training adaptations may be attenuated with increased age. / School of Physical Education

No description available.

The aim of this thesis is to demonstrate the importance of walking to public health. The first part is characterized by epidemiological research. First, a typology for the measurement of walking is developed. A systematic review is conducted of observational studies to determine the health benefits of walking in its own right. Studies consistently confirm that 30 minutes walking on most days of the week is sufficient to reduce the risk of cardiovascular diseases and non-communicable disease risk. Then, a series of epidemiological analyses describes the prevalence and correlates of walking, using multiple health and non-health surveillance data sets. Surveillance data indicate that the prevalence of walking at the above recommended levels is low across all domains. Between 1991 and 2001 an increase in walking occurred, and was the main contributor to reductions in leisure time physical inactivity; however, the proportion of the population who achieved the recommended amount of physical activity by walking did not change in leisure and transport domains. The next part of the thesis is characterized by health promotion research examining the impact of three population-based approaches to increasing walking among Australian adults. The first was an evaluation of a conversion of rail to trail, as an environmental change intervention; the second was a mass media campaign promoting walking to work, and the third was a targeted print media walking program. Providing environmental supports with minimal promotion had no effect on walking. A nation-wide mass media campaign promoting walking to work increased walking and other moderate intensity physical activity, but process evaluation indicated other promotional efforts contributed as well. The targeted print media randomised trial had the greatest effect on walking, but the increases were not greater than spontaneous change in the control. Increases in total physical activity were achieved only when the intervention was supplemented by the use of a pedometer. The expectation that broader approaches to the promotion of walking will bring about changes at the population level, were not corroborated by these case studies. There is a need for enhancement of walking-specific interventions to influence total PA at the population levels.

This study investigated the physiological and psychological limitations to prolonged work performed at different relative intensities, through the use of an eclectic integrative methodology. Ten young male caucasian subjects (mean V0₂ max. 60,0 ml.kg⁻¹.min⁻¹ ± 7,9) were randomly exposed to treadmill runs at each of four relative intensities, namely 55%, 65%, 75% and 85% of V0₂ maximum, with the instruction to run to the point of subjective discomfort at which they were no longer willing to continue. Physiological measures of oxygen consumption (V0₂), heart rate (HR), respiratory exchange ratio (R) , minute ventilation volume (Vi), breathing frequency (Vf), tidal volume (Vt) and psychological measures of Ratings of Perceived Exertion (RPE), Perceived Thermal Comfo·rt (PTC), Perceived Pain and Perceived Fatigue were recorded throughout the protocol. The relative intensity was held constant by slight decreases in treadmill speed as subjects fatigued, and through feedback from an on-line oxygen consumption computer-aided data acquisition system. Significant increases in both physiological and psychological measures occurred with increases in relative intensity (p<0,05). HR and Vf increased overtime (p<0,05) whilst Rand Vt decreased over time (p < 0,05) . All psychological ratings increased in intensity over time (p < 0,05). Mean endurance times to exhaustion were 243 minutes ± 70 at 55% relative intensity, 159 minutes ±37 at 65%, 96 minutes ±25 at 75 % and 23 minutes +- 8 at 85%, being within the range reported by earlier researchers . A regression equation for prediction of endurance time given a known relative intensity was developed for this sample: % V0₂ max. = 117,8 + (-10,6 x LN (time)) (where r = -0,91) Convergence rankings indicate the greater contribution of local factors in the overall gestalt of perceived exertion, pain and fatigue, with biomechanical limitations to prolonged work (running) strongly implicated . High inter correlations between psychological rating scales suggest the use of the scale considered most applicable to the task at hand and the psychological response measure required. A coefficient of multiple correlation of 0,94 established the close interrelationship amongst the physiological and psychological parameters measured. Pre- and post-test Fatigue Cluster Analysis questionnaires indicated that the most important clusters contributing toward the sensation of fatigue and subsequent decision to cease activity were Task Aversion and General Fatigue (r = 0,96), followed by Leg Fatigue and Thirst. Motivation, the task at hand and an attainable goal appear to be important considerations in prolonged work performance. Relative intensity appears a valid tool for use in prolonged work studies due to its high predictive capacity for endurance performance times (r=-0,91). It is concluded that workloads considerably below 55% of maximal aerobic capacity are indicated as acceptable workloads for an 8 hour working day.

The purpose of this study was to examine possible differences between the field and laboratory ratings of perceived exertion (RPE) when the performance and physiological measures for the two conditions were equated. Furthermore, the interactive effects of local, central and overall RPE were examined. Finally, the question of the potential effects of attitudes on RPE was addressed. Eleven well-conditioned adult male marathon runners voluntarily participated in the study. After a period of treadmill habituation, biographical and anthropometric data were collected. This was followed by a VO₂ max test and a speed-matching session at 70% of VO₂ max to determine overground running speed at 3.8% and 7. 5% grade. Subjects then completed an attitudinal questionnaire and ran 4km overground. Finally, the above test was repeated on the treadmill, with the gradient and running speed of the overground condition being replicated. Physiological measures and differentiated RPE were obtained during the final two sessions. There were no physical environmental, task characteristic or performance differences between the overground and treadmill conditions. No heart rate or VO₂ differences were observed between the two conditions, but VE was significantly elevated in the laboratory. Local and overall RPE were significantly higher in the laboratory than in the field, but there was no difference for central RPE. Attitudes were more favourable towards the field than towards the laboratory work task. The results suggest that neither heart rate nor VO₂ are major factors directly influencing the perception of exertion. VE however appears to be a potent central signal mediating RPE. The results also indicate that local factors play a more important role in the perception of exertion than was previously thought. Attitudes towards a work task could possibly mediate the self-reports of exertion. The findings of this study also suggest that RPE are influenced by cognition to a large degree. Finally, environmental cues, or the ambience of a particular working environment, can exert a substantial influence on RPE. Direct perceptual translations from laboratory to field situations may therefore be invalid.

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University of Macau / Faculty of Education