Validity Of Physical Activity Measures Research Articles

Validity of Physical Activity Measures in Individuals After Total Knee Arthroplasty

ObjectiveTo determine the concurrent criterion-related validity of 2 activity monitors in comparison with the criterion method of indirect calorimetry in older adults after total knee arthroplasty (TKA). DesignValidation study. SettingSubjects completed 9 increasingly demanding daily activities in a research laboratory; each activity was performed for 7 minutes, for a total of 80 minutes, while the activity monitors and criterion method were used concurrently. ParticipantsSubjects (N=21, 67% women) had a mean age ± SD of 68±7 years and a body mass index of 29±4. InterventionsNot applicable. Main Outcome MeasuresEnergy expenditure (in kcal/min) measured by accelerometer-based and multisensor-based monitors and by a criterion method. Validity was assessed by the paired t test, intraclass correlation coefficient (ICC), and Bland-Altman plots comparing the measurements from the activity monitors with those of the criterion method. ResultsMeasurements from the accelerometer-based monitor were significantly lower than those of the criterion method across all walking and nonwalking activities. The underestimations ranged from 40% to 100%. The accelerometer-based monitor demonstrated small to moderate agreement compared with the criterion method (ICCs from 0 to .38). Measurements from the multisensor-based monitor were significantly lower than those of the criterion method during several nonwalking activities; yet, the differences were minor (2%–19%). Measurements from the multisensor-based monitor during walking activities were not different compared with the criterion method. The multisensor-based monitor demonstrated moderate to excellent agreement with the criterion method (ICCs from .48 to .81). ConclusionsThe multisensor-based monitor showed better criterion-related validity than the accelerometer-based monitor and should be considered as a tool to measure physical activity in individuals after TKA.

Reliability and validity of the transport and physical activity questionnaire (TPAQ) for assessing physical activity behaviour.

BackgroundNo current validated survey instrument allows a comprehensive assessment of both physical activity and travel behaviours for use in interdisciplinary research on walking and cycling. This study reports on the test-retest reliability and validity of physical activity measures in the transport and physical activity questionnaire (TPAQ).MethodsThe TPAQ assesses time spent in different domains of physical activity and using different modes of transport for five journey purposes. Test-retest reliability of eight physical activity summary variables was assessed using intra-class correlation coefficients (ICC) and Kappa scores for continuous and categorical variables respectively. In a separate study, the validity of three survey-reported physical activity summary variables was assessed by computing Spearman correlation coefficients using accelerometer-derived reference measures. The Bland-Altman technique was used to determine the absolute validity of survey-reported time spent in moderate-to-vigorous physical activity (MVPA).ResultsIn the reliability study, ICC for time spent in different domains of physical activity ranged from fair to substantial for walking for transport (ICC = 0.59), cycling for transport (ICC = 0.61), walking for recreation (ICC = 0.48), cycling for recreation (ICC = 0.35), moderate leisure-time physical activity (ICC = 0.47), vigorous leisure-time physical activity (ICC = 0.63), and total physical activity (ICC = 0.56). The proportion of participants estimated to meet physical activity guidelines showed acceptable reliability (k = 0.60). In the validity study, comparison of survey-reported and accelerometer-derived time spent in physical activity showed strong agreement for vigorous physical activity (r = 0.72, p<0.001), fair but non-significant agreement for moderate physical activity (r = 0.24, p = 0.09) and fair agreement for MVPA (r = 0.27, p = 0.05). Bland-Altman analysis showed a mean overestimation of MVPA of 87.6 min/week (p = 0.02) (95% limits of agreement −447.1 to +622.3 min/week).ConclusionThe TPAQ provides a more comprehensive assessment of physical activity and travel behaviours and may be suitable for wider use. Its physical activity summary measures have comparable reliability and validity to those of similar existing questionnaires.

Comparative Validity of Physical Activity Measures in Older Adults

Comparative Validity of Physical Activity Measures in Older Adults

Comparative Validity of Physical Activity Measures in Older Adults

To compare the validity of various physical activity measures with doubly labeled water (DLW)-measured physical activity energy expenditure (PAEE) in free-living older adults. Fifty-six adults aged ≥65 yr wore three activity monitors (New Lifestyles pedometer, ActiGraph accelerometer, and a SenseWear (SW) armband) during a 10-d free-living period and completed three different surveys (Yale Physical Activity Survey (YPAS), Community Health Activities Model Program for Seniors (CHAMPS), and a modified Physical Activity Scale for the Elderly (modPASE)). Total energy expenditure was measured using DLW, resting metabolic rate was measured with indirect calorimetry, the thermic effect of food was estimated, and from these, estimates of PAEE were calculated. The degree of linear association between the various measures and PAEE was assessed, as were differences in group PAEE, when estimable by a given measure. All three monitors were significantly correlated with PAEE (r=0.48-0.60, P<0.001). Of the questionnaires, only CHAMPS was significantly correlated with PAEE (r=0.28, P=0.04). Statistical comparison of the correlations suggested that the monitors were superior to YPAS and modPASE. Mean squared errors for all correlations were high, and the median PAEE from the different tools was significantly different from DLW for all but the YPAS and regression-estimated PAEE from the ActiGraph. Objective devices more appropriately rank PAEE than self-reported instruments in older adults, but absolute estimates of PAEE are not accurate. Given the cost differential and ease of use, pedometers seem most useful in this population when ranking by physical activity level is adequate.

Validity of Physical Activity Measures During a 23-hour Metabolic Chamber Stay in Older Adults

PURPOSE: To compare the relative validity of various objective physical activity measures with metabolic chamber-measured energy expenditure in older adults. METHODS: Eighteen adults (15 females, 3 males; age= 76 ± 7 (mean ± SD)) wore three activity monitors (New Lifestyles pedometer, Actigraph, and a Sensewear armband) during a 23-hour stay in a metabolic chamber. Subjects had the choice to do a 30-minute exercise video of seated and standing exercises, twice, while in the chamber. Total energy expenditure (TEE) and resting metabolic rate (RMR) were measured with indirect calorimetry, and the thermic effect of food was estimated. Three estimates of physical activity energy expenditure were calculated (PAEE, kcal/d; PAI, kcal/kg/d; PAL, TEE/RMR). Mean differences in TEE and correlations between the various physical activity measures and chamber-measured energy expenditure were compared. RESULTS: TEE was 1796 ± 303 kcal/day. PAEE, PAI, and PAL were 467 ± 148 kcal/day, 3.14 ± 0.91 kcal/kg/day, and 1.57 ± 0.13 (mean ± SD), respectively. On average, 171 ± 49 and 16 ± 11 minutes/day were spent in light and moderate activity, as measured by the Actigraph using count cutpoints of 100, 760, and 5724 cts/min, and the average steps/23 hrs was 862 ± 438. There were no vigorous minutes recorded and the rest of the time was inactive. Although TEE from the chamber and armband were strongly correlated (r=0.69, p<0.01), the armband underestimated TEE by 671 kcals, (p<0.0001). Similarly PAEE from the chamber and armband were correlated (r=0.57, p=0.01), but highly underestimated by the armband (mean difference = 422 kcals). The Actigraph and pedometer did not correlate well with PAEE (r=0.24, p=0.35; r=0.13, p=0.61, respectively), but did tend to correlate with PAI (r=0.42, p=0.08; r=0.41, p=0.10). CONCLUSIONS: Under the highly accurate, but movement limiting conditions of the chamber, the Sensewear armband reasonably ranked older adults by energy expenditure, but the absolute estimates were not accurate. Neither accelerometry nor pedometry did as well as the multi-sensor device.

The effect of walking mobility on the measurement of physical activity using accelerometry in multiple sclerosis

Objective: To examine whether accelerometry provides a measure of physical activity, walking ability or both in a sample of individuals with multiple sclerosis. The secondary purpose was to examine the validity of physical activity measures in people with multiple sclerosis who have ambulatory impairments. Participants: Forty-two individuals with multiple sclerosis without ambulatory impairment (Expanded Disability Status Scale (EDSS) score ≤ 4.5) and 32 individuals with multiple sclerosis with ambulatory impairment (EDSS ≥5.0). Method: Participants completed the Multiple Sclerosis Walking Scale-12 and Performance Scales, wore an accelerometer for seven days, and completed the Godin Leisure-Time Exercise Questionnaire and short-form of the International Physical Activity Questionnaire. Results: There were significant differences between groups on scores from the five measures. There were large correlations between the accelerometer counts with scores from both the self-report measures of physical activity and the self-report measures of walking mobility in the overall sample. There were large correlations between scores from both measures of physical activity in the overall sample and the subsample with ambulatory impairment. Conclusion: Our data suggest that accelerometers are measuring both physical activity and walking mobility in individuals with multiple sclerosis, whereas self-report measures are measuring physical activity in individuals with multiple sclerosis, including those with ambulatory impairment.

Validity of physical activity measures in ambulatory individuals with multiple sclerosis

Purpose. The literature suggests that individuals with multiple sclerosis (MS) engage in less physical activity than non-diseased individuals. That conclusion, however, depends upon the validity of scores from measures of physical activity among the MS population. This study evaluated the validity of scores from two self-report surveys, a pedometer, and an accelerometer and during seven days of free-living conditions among individuals with MS.Method. Participants were 30 individuals (28 females, two males) with an established definite diagnosis of MS. The participants wore a pedometer and a single-axis accelerometer during the waking hours of a 7-day period. After the 7-day period, participants returned to the lab and completed a self-administered physical activity questionnaire and then underwent a 7-day physical activity recall.Results. There were strong correlations (a) between scores from the two self-report measures of physical activity and (b) between scores from the two objective measures of physical activity, and (c) weaker, but moderate-to-strong correlations between scores from the self-report and objective measures of physical activity.Conclusion. Our results support the quantification of physical activity among those with MS using validated self-report and objective measures.

Measurement of Physical Activity

This paper describes the problem of measuring physical activity in free-living populations, a premier challenge facing investigators trying to understand exercise adherence and its impact on public health. Valid methods of assessing physical activity are required that are unobtrusive, practical to administer, and specific about the type, frequency, duration, and intensity of physical activity, Existing methods can be categorized according to whether they measure a direct or indirect (e.g., self-report) observation of physical activity, energy expenditure, a physiological response during physical activity. a physiological adaptation to physical activity, or motion. On balance, self-reponof physical activity offers the most practical and cost-effective method for use in population based studies. Several objective methods such as direct observation. doubly labeled water. heart rate monitors, accelerometers, and change in fitness provide standards of comparison for the validation of self-reports. No single “gold standard” exists for judging the validity of physical activity measures. Hence, the methods chosen to assess physical activity may vary according to the nature of the research question being addressed.