| Summary: | The U.S. Department of Health and Human Services has made the promotion
of regular physical activity a national health objective, and experts believe that
physical education can play a significant role in the promotion of physical activity.
Feasible measurement tools to assess physical activity behavior, by physical
educators, are lacking. One validated instrument is the System for Observing Fitness
Instruction Time (SOFIT; McKenzie, Sallis & Nader, 1991). SOFIT's physical
activity data are collected using momentary time sampling (MTS) with a 20-second
interval length and provide estimates of Moderate to Vigorous Physical Activity
(MVPA). Whether variations in interval lengths would adversely affect the accuracy
of the MVPA data has not been investigated. From a clinical perspective, if physical
education teachers are to utilize MTS procedures for on-going assessment they will
require longer time intervals to collect accurate MVPA data. Therefore, this project
sought to determine the accuracy of MVPA levels collected through varying
observation tactics (i.e., 20s, 60s, 90s, 120s, 180s, and random) relative to those
collected through duration recording (DR). Video records of 30 randomly selected
elementary school physical education classes were utilized for this study. Utilizing
modified physical activity codes from SOFIT, the researchers collected MTS data
regarding students' MVPA at varying interval lengths (i.e., 20s, 60, 90s, 120s, 180s,
and random). Three statistical techniques, Pearson-product moment (PPM) correlation
coefficients, Repeated Measures Analysis of Variance (RM ANOVA), and Average
Error (AE), were utilized to demonstrate concurrent validity of the varying interval
lengths. Results demonstrated moderate-low to high correlations between the 20s,
60s, 90s, and random interval lengths and the DR tactic during the total class. The
RM ANOVA indicated similarity between all the varying interval lengths and the DR
tactic for total class observation. The MTS procedure that created the least amount of
AE across classes was the 20s variable followed by the 60s, random, and 90s
variables. These findings build empirical evidence for the use of a 60s, random, and
90s MTS procedure for the purpose of MVPA assessment by physical educators. === Graduation date: 2004
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