Biomedical subjects

Matthew T Mahar

Publications and source records attributed to Matthew T Mahar.

3 recordsLinked to original sources

PubMed2006

Effects of a classroom-based program on physical activity and on-task behavior.

PURPOSE: This study evaluated the effects of a classroom-based physical activity program on children's in-school physical activity levels and on-task behavior during academic instruction. METHODS: Physical activity of 243 students was assessed during school hours. Intervention-group students (N = 135) received a classroom-based program (i.e., Energizers). The control group (N = 108) did not receive Energizers. On-task behavior during academic instruction time was observed for 62 third-grade (N = 37) and fourth-grade students (N = 25) before and after Energizers activities. An independent groups t-test compared in-school physical activity levels between intervention and control classes. A multiple-baseline across-classrooms design was used to evaluate the effectiveness of the Energizers on on-task behavior. Additionally, a two-way (time [pre- vs postobservation] x period [baseline vs intervention]) repeated-measures analysis of variance compared on-task behavior between observation periods. Magnitudes of mean differences were evaluated with Cohen's delta (ES). RESULTS: Students in the intervention group took significantly (P < 0.05) more in-school steps (5587 +/- 1633) than control-group students (4805 +/- 1543), and the size of this difference was moderate (ES = 0.49). The intervention was effective in improving on-task behavior; after the Energizers were systematically implemented, on-task behavior systematically improved. The improvement in on-task behavior of 8% between the pre-Energizers and post-Energizers observations was statistically significant (P < 0.017), and the difference was moderate (ES = 0.60). Likewise, the least on-task students improved on-task behavior by 20% after Energizers activities. This improvement was statistically significant (P < 0.001) and meaningful (ES = 2.20). CONCLUSION: A classroom-based physical activity program was effective for increasing daily in-school physical activity and improving on-task behavior during academic instruction.

Attention↗

PubMed2005

Multitrait-multimethod investigation of a novel body image measurement technique.

A multitrait-multimethod (MTMM) matrix was used to evaluate validity evidence for a digital image manipulation (DIM) body image measurement technique in young women. One hundred one young women completed the DIM procedure and the Thompson and Gray (1995) Contour Drawing Rating Scale to measure self-ideal discrepancy and size perception accuracy components of body image. Seven-day test-retest reliability was acceptable (R = .81-.95). Convergent validity for self-ideal discrepancy was higher (r = .74) than the corresponding heterotrait, monomethod coefficients (r = .46, r = .23) and heterotrait-heteromethod coefficients (r = .18, r = .12). However, the convergent validity coefficient for size perception accuracy was r = .12. The pattern of correlations in the MTMM matrix met the criteria of Campbell and Fiske (1959) for validity of these procedures to measure self-ideal discrepancy but not size perception accuracy. The DIM procedure addresses some of the criticisms associated with figure-rating scales, such as unrepresentativeness of the figures, scale coarseness, and restriction of range in responses. DIM, therefore, represents a realistic, valid alternative to figure-rating scales for measuring self-ideal discrepancy.

Adolescent↗

PubMed2003

Influence of body composition on physical activity validation studies using doubly labeled water.

This study investigated the influence of two approaches (mathematical transformation and statistical procedures), used to account for body composition [body mass or fat-free mass (FFM)], on associations between two measures of physical activity and energy expenditure determined by doubly labeled water (DLW). Complete data for these analyses were available for 136 African American (44.1%) and Hispanic (55.9%) women (mean age 50 +/- 7.3 yr). Total energy expenditure (TEE) by DLW was measured over 14 days. Physical activity energy expenditure (PAEE) was computed as 0.90 x TEE - resting metabolic rate. During week 2, participants wore an accelerometer for 7 consecutive days and completed a 7-day diary. Pearson's product-moment correlations and three statistical procedures (multiple regressions, partial correlations, and allometric scaling) were used to assess the effect of body composition on associations. The methods-comparison analysis was used to study the effect of body composition on agreement. The statistical procedures demonstrated that associations improved when body composition was included in the model. The accelerometer explained a small but meaningful portion of the variance in TEE and PAEE after body mass was accounted for. The methods-comparison analysis confirmed that agreement with DLW was affected by the transformation. Agreement between the diary (transformed with body mass) and TEE reflected the association that exists between body mass and TEE. These results suggest that the accelerometer and diary accounted for a small portion of TEE and PAEE. Most of the variance in DLW-measured energy expenditure was explained by body mass or FFM.

Adult↗