Just to be clear here... actometer's weren't a part of the Pace protocol. But in the comments section for that paper White says that there was a plan to use actomemters, but that these were droppped because of the inconveniece thaty'd cause patients (?!).
If the actometers, which are designed to be as unobtrusive and convenient as possible to wear, are too much hassle for patients, then the patients must be pretty physically limited to start with.
The lack of objective activity measures seriously limits the validity of the already modest results.
Also found these, not sure if they have been posted here before. Overall they seem to indicate a high validity for actometers as a measure of overall activity, but that pedometers are not so reliable.
The use of pedometer and actometer in studying daily physical activity in man. Part I: Reliability of pedometer and actometer.
W. H. M. Saris and R. A. Binkhorst
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY
Volume 37, Number 3, 219-228, DOI: 10.1007/BF00421777
The purpose of this study was a critical evaluation of pedometer and actometer for estimating daily physical activity.
Both instruments were tested for reliability on a carriage with movements in different directions. To obtain comparable data of different pedometers it was necessary to adjust the spring tension very carefully. The reliability of the individual actometer was satisfactory, but there are large differences between the watches. Therefore, a correction factor (C.F.) was introduced.
Some experiments were carried out on a treadmill. 9 Children (aged 56 years) and 6 young adult males (aged 2131 years) walked and ran at different speeds. The energy expenditure was calculated from formulas. The pedometer overestimates the actual step rate with 0.10.3 counts per step during fast walking (69 kmh1) and fast running (15 kmh1). It underestimates the actual step rate with 0.20.7 counts per step, while walking slowly. It was shown that the pedometer does not reflect the differences in energy expenditure levels at different speed very well. The actometer units per step increases more or less proportional to the speed of walking and running. In contrast to the pedometer results the actometer results are more related to the energy expediture levels at different speed.
The results of this study suggest that the actometer might be a valid indicator of the daily physical activity in terms of energy expenditure.
The use of pedometer and actometer in studying daily physical activity in man. Part II: Validity of pedometer and actometer measuring the daily physical activity.
Authors: W. H. M. Saris and R. A. Binkhorst
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY
Volume 37, Number 3, 229-235, DOI: 10.1007/BF00421778
The validity of the pedometer and actometer for estimating the daily physical activity was evaluated by means of an observation study. The physical activity in a classroom of 11 pupils of a kindergarten was assessed by means of a pedometer, actometer and by observation. Besides this an activity questionnaire was completed by the infant-quide. On basis of the individual observation it is clear that the infant-guide can give valuable information about the activity of the children at school.
The results of the pedometer attached to the waist and the actometers attached to the ankle were significantly correlated with the results of the observation method. The wrist actometer showed a smaller but still significant correlation with the other variables. Implications of this findings are discussed in regard toward the physical activity. The pedometer results point out that when the percentage of intense activity is high the pedometer tends to underestimate the level of activity.
The actometer results indicate that such a motion recorder gives a reliable estimation of activity in children. The findings are discussed in terms of the practical applications of the actometer in the research of daily physical activity and the physical rehabilitation treatment of certain diseases.
Measuring Activity Level with Actometers: Reliability, Validity, and Arm Length.
Authors: Eaton, Warren O.
Child Development, v54 n3 p720-26 Jun 1983
The gross-motor activity of 27 three- and four- year-olds was assessed through teacher ratings, parent responses to the activity scale of the Colorado Childhood Temperament Inventory, and data from uncalibrated actometers worn by children during free play. Activity scores composited across multiple actometers had high reliability and correlated strongly with the other two measures.
Correlations of pedometer readings with energy expenditure in workers during free-living daily activities.
Hiroshi Kashiwazaki, Tsukasa Inaoka, Tsuguyoshi Suzuki and Yasuyuki Kondo
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY
Volume 54, Number 6, 585-590, DOI: 10.1007/BF00943345
... The whole day readings of the pedometer for all the subjects moderately correlated (r=0.438,p<0.05) with the net energy cost (NEC) as determined by subtracting the sleeping metabolic cost from the energy expenditure (clerical workers:r=0.781,p<0.01; assembly workers:r=0.188,p>0.05). The correlation analysis of the pedometer readings with the NEC in three activity phases in a day (work, commuting and staying at home), showed that the extent of the relationship differed by job types and activity phases. The best correlation was obtained during commuting in both of the job types (clerical workers:r=0.843,p<0.01; assembly workers:r=0.743,p<0.01). During work, a quite strong correlation (r=0.889,p<0.01) was obtained with the clerical workers but not with the assembly workers. No significant correlations were found in the data while the subjects were at home. The capacity of the pedometer to detect the impacts of body movements, and the characteristics of activity, are responsible for the differences in correlation. The limitations of the pedometer suggested in the present study must be taken into account if the device is to be used for measuring physical activity. A particular advantage of the device appears in its use for a sedentary population without regular srenuous exercise or static contractions.
Approaches to estimating physical activity in the community: calorimetric validation of actometers and heart rate monitoring.
Avons P, Garthwaite P, Davies HL, Murgatroyd PR, James WP.
Dunn Clinical Nutrition Centre, Cambridge, UK.
Eur J Clin Nutr. 1988 Mar;42(3):185-96.
The relationship between actometer measurements, heart rate monitoring and energy expenditure during exercise and resting periods was assessed in a whole-body indirect calorimeter on 12 young male volunteers. Equations derived from these studies were applied to actometer measurements taken during a further 7 d recording in free-living conditions to predict daily energy expenditure over 1 week on an individual basis. Actometers proved to be a satisfactory means of estimating energy expenditure and heart rate monitoring improved the estimates in a few selected subjects. Indirect measures of energy expenditure could be developed by this approach but individual calibration is essential.
Measuring activity using actometers: A methodological study
Warren W. Tryon
JOURNAL OF PSYCHOPATHOLOGY AND BEHAVIORAL ASSESSMENT
Volume 6, Number 2, 147-153, DOI: 10.1007/BF01350169
Actometers are men's self-winding mechanical wristwatches that have been modified such that they measure activity rather than time. Actometers can be used to obtain longitudinal naturalistic measures of activity concerning a variety of clinical populations. However, no systematic methodological research has been conducted with regard to the site of attachment and the duration of measurement necessary to ensure valid results. This article presents the results of a methodological study designed to answer these questions. The mean activity levels associated with the Left Wrist and Ankle were nearly equal to those associated with the Right Wrist and Ankle. The Ankle readings were substantially greater than the Wrist readings because the subjects' legs were longer than their arms. The data from Week 2 were the same as those from Week 1.