Wednesday, May 18, 2011
PC reports high levels of participant physical activity in latest study
Project Coach’s Use of Actigraph Accelerometers Provides Objective Health Benefits for Youth and Beyond
By: Kathleen Boucher
The Physical Activity Guidelines for Americans states that children and adolescents should do 60 minutes (1 hour) or more of physical activity each day. Activity, however, needs to not only be moderate to vigorous physical activity (MVPA) but it also needs to be age appropriate. While Project Coach continually strives to provide a venue to meet such recommendations, the spring of 2011 marked the first year that Project Coach has been able to use state of the art technology, namely accelerometers, to objectively measure its strides. Accordingly, this entry will describe how Project Coach has already been using the accelerometers as well as the far-reaching benefits that such data can have for the many layers of Project Coach as well as the Springfield community at large.
Why is an Accelerometer Useful When Measuring Moderate and Vigorous Physical Activity?
The Center for Disease Control suggests that parents can think about moderate and vigorous intensity in two ways. First, considering a scale of 0 to 10, where sitting is a 0 and the highest activity level is a 10, moderate-intensity activity would be a 5 or 6 and vigorous-activity would be a 7 or 8. During moderate-intensity activity, a child’s breathing would be harder than normal and the heart will beat faster than a normal resting level. Accordingly, during vigorous-intensity activity, a child’s breathing would be much harder than normal and the heart would beat much faster than normal. A second way of thinking about this is if a child walks to school in the morning then she or he is most likely doing moderate-intensity aerobic activity. However, when she runs during recess or is being chased during a game of tag, she is probably doing vigorous-intensity activity. While these are useful measures, they only provide subjective results since an individual can say a child is “probably” engaging in a certain level of activity. Such measurements are further difficult for a sports coach to monitor when she or he has at least nine different children to watch at the same time. Technology has provided ways to aide such measurements.
Over the years, many tools have been developed to provide objective, empirical measurements of physical activity. For example, while a pedometer measures activity in equal-length two-dimensional steps, accelerometers measure random activity on three axes. Research studies have validated the use of Actigraph accelerometers as a useful device for the assessment of physical activity in children. Therefore, accelerometers, in this case worn on a belt on a child’s waist, provide accurate and non-invasive measurements for the amount and intensity of activity. Such data is invaluable to ensure that a program’s practices are not only striving to meet daily activity standards for children, but that those goals can actually and consistently be met. It is for these reasons that Project Coach came to acquire ten Actigraph Accelerometers to help inform their practice.
What Project Coach Did
During this past spring basketball season of Project Coach, eight 5th grade kids from Brightwood Elementary School in Springfield, Massachusetts wore accelerometers on two separate school days in which they would also attend Project Coach after school. With the help of the school’s PE teacher, Mr. Dalessio, the accelerometers were distributed when the students arrived at school in the morning. The students then proceeded to wear them all day at school and during Project Coach after school. The first trial day, a Tuesday, was a Project Coach practice session and the second trial day, a Friday, was a Project Coach game day. The accelerometers were set to collect data from 9AM-5PM.
How The Accelerometer Data Were Analyzed
Two different procedures were employed to analyze the accelerometer data. Once the data were uploaded using the Actigraph software, total activity counts were computed from 9 a.m.-5 p.m. Then, total activity counts were measured during the 4 p.m. -5 p.m. hour when children were participating in Project Coach. Using these two numbers, it was possible to calculate the percentage of activity children had when participating in Project Coach (4 p.m. -5 p.m.) and during each of the hours that they were in school (9 a.m. -4 p.m.). Our first question was how activity during a Project Coach hour compared to activity during a typical hour during a child’s school day.
Second, the raw data were also analyzed using a mathematical algorithm that computed the amounts of sedentary, light, moderate, and, vigorous physical activity children obtained while in school and while participating in Project Coach These categories identify common daily physical activity standards and can therefore be used to determine whether children in our program were getting recommended levels of physical activity.
The Project Coach Hours
Based on the 3 dimensional activity counts, this study found, 35% of activity that kids got between 9 a.m. and 5 p.m. were during the Project Coach (4 p.m. -5 p.m.) time block. Therefore, in the 8 hour time period, 35% of the students’ activity occurs during this 1 hour. As well, Graph 1 shows that, during the Project Coach hour kids get about 3.85 times the activity that they get during a typical hour in school! This suggests that Project Coach provides a venue for physical activity that is not available during the school day. The use of accelerometers thus provides empirical data to depict the extent to which Project Coach kids are relatively more active while at Project Coach practices and game days.
Meet Daily Moderate and Vigorous Physical Activity Requirement
As well, Graph 2a shows that in Project Coach, children’s activity is structured as: 7% sedentary—(1-1.5 METS), 30% (Light—1.5-3 METS), 57% (Moderate—3-6 METS), and 6% (Vigorous—6-9 METS). In contrast, a typical school hour between 9-4 would look like 51% (Sedentary); 39% (Light), 10% (Moderate), and 0.0% (Vigorous). Furthermore, when converted to a minute-to-minute breakdown Graph 2b shows that during a Project Coach hour practice or game, kids are only sedentary for 4.2 minutes and engaged in moderate or vigorous activity for 37.8 minutes.
Overall A Good Pilot Study
Overall the data above do indicate that Project Coach is adding significantly to the amount of physical activity children are getting in a typical day. Because of scheduling, we were on unable to measure the activity levels of Project Coach youth during the 4-5 p,. hour on days when they are not attending the program. However, because of a mix-up in assigning accelerometers to kids, we did manage to collect data from a fifth grader who attended the Brightwood Afterschool Program instead of Project Coach. This participant received 10% of her activity between 4-5 p.m. (contrast with 35% for Project Coach kids). This was also less than she got in an average hour during her school day, which was 14% per hour. During the 4PM-5PM hour, she worked at 1.5 METS, and had the following profile: 63% sedentary, 32% light, and 5% moderate activity. Therefore, during her afterschool hour, she only received 3 minutes of activity that reached a moderate to vigorous activity level (in contrast to Project Coach kids who got nearly 38 minutes). While this was only one participant, it further suggests that Project Coach provides a venue for students to be significantly more active than they would be without Project Coach
Our initial work using accelerometers has a number of important implications for Project Coach. Clearly, the data show that kids in our program are getting significantly more physical activity than they typically get during their school day. The data also provides information about the structure and intensity of activity children obtain during the time they are with us. Using these baseline data, we are now able to provide our coaches with feedback about how what they do in practices and games impacts the activity levels that their players are getting. While the results from this pilot study indicate that they have been doing good work, we think that there is also room for improvement. Next year we will be focusing on increasing the amount of vigorous activity that participants get in Project Coach.
Posted by Andy Wood at 12:22 PM