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Nerissa Campbell, Anca Gaston, Casey Gray, Elaine Rush, Ralph Maddison and Harry Prapavessis

Background:

Accurate assessment of physical activity energy expenditure (PAEE) among adolescents is important for surveillance, evaluating interventions, and understanding the relation between energy balance and normal physiological and behavioral growth and development. The purpose of this study was to examine the validity of the Short Questionnaire to Assess Health-Enhancing Physical Activity (SQUASH)13 for measuring PAEE among adolescents.

Methods:

The participants were seventeen adolescents (9 females; Mean age = 17.53; SD = 0.62). Energy expenditure was measured during a 9-day period with doubly labeled water (DLW). The SQUASH was self-administered on the morning of the 10th day and assessed commuting activities, leisure time activities, household activities, and activities at work and school over the previous 9 days.

Results:

A Bland-Altman plot indicated that the SQUASH underestimated PAEE compared with DLW by a mean difference of 126 kcal·d−1 (95% limits of agreement: –1,207 to 1,459 kcal·d−1), representative of a 10% underestimation. The Spearman rank order correlation coefficient showed there was a significant association between the SQUASH and DLW (r = .50, P = .04), for estimating PAEE.

Conclusion:

When using a sample of highly active adolescents, the SQUASH is a valid self-report tool for measuring PAEE at the group and individual rank order level.

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Travis Saunders, Nerissa Campbell, Timothy Jason, Gail Dechman, Paul Hernandez, Kara Thompson and Chris M. Blanchard

Background:

Although individual studies have reported on the number of steps/day taken by individuals with chronic obstructive pulmonary disease (COPD), this evidence has not been systematically reviewed or synthesized.

Methods:

MEDLINE and PsycINFO were searched for studies reporting objectively-measured steps/day and percent predicted forced expiratory volume in 1 second (FEV1%) in patients with COPD. Meta-analyses were used to estimate steps/day across studies, while metaregression was used to estimate between-study variance based on clinical and demographic factors (year and location of study, activity monitor brand, number of days wearing the monitor, whether participants were about to enter pulmonary rehabilitation, 6-minute walk distance (6MWD), FEV1%, age, and sex).

Results:

38 studies including 2621 participants met inclusion criteria. The pooled mean estimate was 4579 steps/day (95% CI:4310 to 5208) for individuals with COPD. Only 6MWD, FEV1% and whether patients were about to undergo pulmonary rehabilitation explained a significant portion of the variance (P < 0.1) in univariate meta-regression. In a multivariate model including the above risk factors, only FEV1% was associated with steps/day after adjustment for other covariates.

Conclusions:

These results indicate that patients with COPD achieve extremely low levels of physical activity as assessed by steps/day, and that severity of airflow obstruction is associated with activity level.

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Nerissa Campbell, Harry Prapavessis, Casey Gray, Erin McGowan, Elaine Rush and Ralph Maddison

Background/Objective: This study investigated the validity of the Actiheart device for estimating free-living physical activity energy expenditure (PAEE) in adolescents. Subjects/Methods: Total energy expenditure (TEE) was measured in eighteen Canadian adolescents, aged 15–18 years, by DLW. Physical activity energy expenditure was calculated as 0.9 X TEE minus resting energy expenditure, assuming 10% for the thermic effect of feeding. Participants wore the chest mounted Actiheart device which records simultaneously minute-by-minute acceleration (ACC) and heart rate (HR). Using both children and adult branched equation modeling, derived from laboratory-based activity, PAEE was estimated from the ACC and HR data. Linear regression analyses examined the association between PAEE derived from the Actiheart and DLW method where DLW PAEE served as the dependent variable. Measurement of agreement between the two methods was analyzed using the Bland-Altman procedure. Results: A nonsignificant association was found between the children derived Actiheart and DLW PAEE values (R = .23, R 2 = .05, p = .36); whereas a significant association was found between the adult derived Actiheart and DLW PAEE values (R = .53, R 2 = .29, p < .05). Both the children and adult equation models lead to overestimations of PAEE by the Actiheart compared with the DLW method, by a mean difference of 31.42 kcal·kg·d−1 (95% limits of agreement: −45.70 to −17.15 kcal·kg−1·d−1 and 9.80 kcal·kg−1·d−1 (95% limits of agreement: −21.22-1.72 kcal·kg−1·d−1), respectively. Conclusion: There is relatively poor measurement of agreement between the Actiheart and DLW for assessing free-living PAEE in adolescents. Future work should develop group based branched equation models specifically for adolescents to improve the utility of the device in this population.