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HOW WE TEACH
1 Human Performance Laboratory 2 Center for Science Education, University of Wisconsin Milwaukee, Milwaukee, Wisconsin
Address for reprint requests and other correspondence: A. C. Snyder, Dept. of Human Movement Sciences, PO Box 413, Univ. of Wisconsin Milwaukee, Milwaukee, WI 53201 (e-mail: acs{at}uwm.edu)
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Abstract |
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Key words: applied science; field trips
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Introduction |
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The recently developed "Healthy People 2010", a PHS-led national activity for setting priority areas for health promotion and disease prevention, has two main goals: 1) increasing the quality and years of healthy life and 2) eliminating health disparities (10). Although life expectancy has increased greatly over the last decade, males in 25 non-US countries currently have life expectancies greater than those in the United States (73 yr for those born in 1990s) and 17 countries have longer life expectancies for females than do those in the United States (79 yr for those born in 1990s) (10). Life expectancy and quality of life are both hypothesized to be enhanced by helping people gain knowledge, motivation, and opportunity to live healthier lives (10). A healthy life disparity occurs due to gender, ethnicity or race, education and/or income, disability, and location. Thus greater knowledge and exposure to healthy aspects of life should enhance these two goals.
The 28 focus areas of Healthy People 2010 include 12 areas directly affected by exercise and/or nutrition: diabetes, arthritis, osteoporosis and chronic back pain, nutrition and overweight, chronic kidney disease, physical activity and fitness disabilities, respiratory diseases, education and community-based programs, cancer, health communications, heart disease and stroke, and injury and violence prevention. According to 1997 information, the four leading causes of death (heart disease, cancer, stroke, and chronic obstructive pulmonary disease) along with diabetes (the seventh leading cause of death) could all be reduced with proper exercise and nutritional practices (10). We know that performance of regular exercise decreases the incidence of heart disease, colon cancer, high blood pressure, and diabetes, while increasing muscle and bone strength and lean tissue mass (2). Regular exercise also aids in weight control and is a key part of weight loss through the decrease of fat mass (11). Performance of regular exercise also enhances psychological well-being (2). Similarly, proper nutrition can affect these leading causes of death (3).
The 1996 National Science Education Standards set forth by the National Research Council and followed by individual states and schools sought to address the science deficiencies and enhance the science curriculum (9). The standards include sections where science, health, exercise, and nutrition content can be merged and applied activities developed. In so doing, the study of the sciences and health can be an integrative and active process, not one where memorization predominates. Rather, an experience of exploring, observing, problem solving, and discussing in an engaging classroom atmosphere takes place. The overall goal of this program was to develop an integrated scientific program for students in grades 2–12 that would enhance and enrich the scientific, mathematic, and health knowledge of the students and their classroom teachers through an interactive and engaging atmosphere.
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METHODS |
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Pre-river packet.
The pre-river packet was given to teachers 
2 wk before the off-campus/park program. The packet outlined the different modules and the information needed to be presented in class before the park program. The pre-river packet had introductory information covering the different topics to be discussed, so the teachers, if not the students, could be well-informed, depending on the amount of preprogram preparation. Instructors were available to meet with the teachers and students before the river trip. Three schools chose this option.
Park program.
After the instructors met the students and introduced themselves, the students received a handout covering the different activities. A brief verbal introduction into the program and its purposes followed. Because the park program was part of a canoe trip for the instructors, the first topic was transportation and how we visit our friends (via canoe, or the most common answer was "Have mom drive me"). The conversation continued with other examples of energy-saving technology, i.e., dishwashers, lawn mowers, vacuum cleaners, and remote controls, which led into the discussion of exercise and the need for it. The different types of muscle contractions were described–isometric, isotonic (both eccentric and concentric), and isokinetic. The students felt the movement of their muscles while performing isometric, concentric, and eccentric contractions. Fast and slow muscle fibers were discussed, illustrated with the general percentage that different athletes tend to have. A discussion of the body’s energy sources followed, including the need for ATP for muscle contraction and when various stored energy sources (ATP, creatine phosphate, carbohydrates, fats, and proteins) are used (Table 1). Students labeled the primary energy source for seven activities: sleeping, walking slowly, sprinting, bike racing, canoeing, one repetition bench press (which had been demonstrated), and an activity of their choosing. The students shared their results and the activity of their choosing with the group. Finally, the concepts of heat generation during energy production and good ways to expend lots of energy were discussed.
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Respiratory module.
During the respiratory module, the students predicted and measured their tidal volume (the amount of air that moves in and out of the lungs in one breath). Students also measured their vital capacity volume by maximally exhaling into the spirometer. Students recorded their values and their weight. The students were asked to compare each other’s values. A parent or teacher was asked to measure their vital capacity volume to provide a comparison to a larger individual. The older age group students also recorded the hobbies and the sports they played, as a simple indicator of fitness for comparative purposes. The goal of the respiration module was to show how much air the lungs could draw in one breath and to compare lung capacity to the size and fitness of an individual.
Cardiovascular module.
During the cardiovascular module, the students used stethoscopes to listen to heart sounds and to determine heart rate. Students also calculated heart rate by feeling the artery in the wrist and neck, and compared the heart rates obtained at different sites. Finally, the students completed a short bout (i.e., 30 s) of exercise, usually jumping jacks or running, and then remeasured their heart rates. Heart rate was related to the intensity and type of activity performed. This may have been the first time that younger students heard their own heart sounds. Older students were asked to predict heart rates for the various activities they performed. Students who could not hear their heart sounds or feel their pulse while resting could easily measure it after exercise. The goal of the cardiovascular module was to demonstrate different ways that heart rate could be determined, the advantages and disadvantages of each method, and how heart rate changes with exercise.
Oxygen uptake at rest and exercise module.
The oxygen uptake at rest and exercise module was the most complex and technology-specific module. Oxygen uptake was obtained through the use of a MetaMax 3B portable system (Woodway, Waukesha, WI). Heart rates and oxygen uptake were recorded by students at rest and at four different intensities of exercise (cycling at: 3 min at 1 W/kg, 3 min at 2 W/kg, 3 min at 3 W/kg, and then to exhaustion at 4 W/kg). Calories expended and the respiratory exchange ratio showing the energy source for different intensities of exercise were observed and recorded. Finally, respiratory dynamics (breathing frequency and ventilation volume) and concentrations of oxygen and carbon dioxide were recorded at rest and during the different intensities of exercise. The data were displayed, in real time on a laptop computer, to show the changes that occurred over time of any or all of the measurements. For younger students, the display was simplified to show heart rate, oxygen uptake, and respiratory dynamics. Older students were asked to predict measurements at the different exercise intensities. Older students also determined whether carbohydrates or lipids was the major fuel being used through observation of the respiratory exchange ratio. The goal of the oxygen uptake module was to illustrate how scientists determine exercise-related body functions in a precise way and how these functions are interrelated.
Energy expenditure module.
One of the student’s prepark assignments was to calculate the number of metabolic equivalents (METS) they had used outside of school on a typical day. Once their METS were determined, a daily expenditure was estimated (4, 13, 14). In the energy expenditure module, the students balanced their daily caloric expenditure with food intake using a double beam balance and weighted cards for both energy expenditure and food intake. The foods used to "balance" the caloric expenditure were compared with the food pyramid. This module was eliminated for students in the second grade. The goal of the energy expenditure module was to increase student awareness of the importance of exercise in increasing caloric expenditure and to learn the caloric value of some common foods.
Body temperature regulation.
The last module was body temperature regulation where students measured skin temperature of their forehead, neck, and wrist through the use of a Dermatemp device (Exergen, Watertown, MA) which measures heat emitted from the body surface by infrared thermometry. The measurements at the three sites were compared with other data collected on other days of the program at different air temperatures. Daily temperatures ranged from 45–80°F during the 2-wk program. Students were asked to compare their normal body temperature to their skin temperature and to the environmental temperature. Older students were asked to explain the difference between the temperatures. The goal of the body temperature regulation module was to demonstrate how the body cools itself.
After all students had performed all modules, a short wrap-up occurred. During this time, the need for different types of exercise was stressed, what happens to the body during exercise was discussed, and the students were quizzed on how the effect of exercise was healthful to our bodies.
Web site.
A world wide web site that had a physiological, nutrient, and weather emphasis was updated and available to students each day following the activities of the 2-wk canoe trip of the instructors. The physiological topics were: preparing the body for adventure, muscles and movement, heart and blood vessels, respiration, blood, temperature regulation, skin, regulation by the nervous and endocrine systems, injuries and illnesses, energy expenditure and body composition, and digestion and excretion. The nutrient topics of the day were: basic nutritional requirements of the body, proteins, lipids and cholesterol, oxygen, vitamins, water, fats, minerals, carbohydrates, and fiber. The weather topics of the day were: lightning, dew point and humidity, clouds, rain, snow, air pressure, fronts, wind, temperature, and air quality. The three topics of the day complemented the park programs, including the weather aspects, which definitely affects exercise performance and health. Each day the web site had questions associated with the material in the science challenge (e.g., can muscles contract at different speeds, or how does humidity affect exercise and body function?). A daily trip diary, also on the web site, reported the instructors’ activities and observations for the day and included the data collected.
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RESULTS AND DISCUSSION |
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The teachers and parents were quite capable of running the respiration, cardiovascular system, energy expenditure, and body temperature regulation modules and their comments after the program indicated they enjoyed themselves and learned a bit themselves. The teachers were asked to complete an assessment form several weeks after the program was completed. The questions were grouped into three categories: preliminary contacts, day of program, and reflections on the program. Seven of the eighteen teachers completed the form. The low percentage of written evaluations returned was probably due to the lateness of the program (late spring) in the school year because overall evaluations of the program both verbal (during) and written (afterward) were positive.
For the preliminary contact assessment, teachers were asked about the pre-river handout. All of the teachers thought that the pre-river handout helped to prepare them and their students. Two of the teachers thought the handout was too lengthy and wanted a pre-river handout specific for their grade level. The other five teachers liked the handout, because it was challenging, and they could pick and choose what they needed from several levels. All of the teachers thought doing an activity before the off-campus park program helped the students prepare. The handout would have been more effective, the survey showed, if it had been given to the teachers more than 2 wk before the off-campus park program.
In the section assessing the off-campus park program day itself, teachers were pleased with the organization overall, but would have liked more time for the actual program. When teachers reflected on the program, they were in agreement that the topic of nutrition and exercise was appropriate for their students and that ties to the science curriculum made the program worth using school time. Examples of teachers’ responses to the question "In your perception, what was the educational benefit for your students and yourself?" indicated that the "real world" application of the science was an important aspect of the program. Students were able to see school learning tied into other learning activities. In addition, the teachers received very positive feedback from the parents who had volunteered, possibly encouraging further participation in programs similar to this one.
From the instructors’ perspective, the park program went well. Having five different modules at one time with only two instructors could have been a real problem, but the teachers and parents were oriented by one instructor while the other instructor provided the introduction to the students. For five of the days, a high school student volunteered to help, improving the overall delivery of instruction. The high school student circulated among the groups, making sure that the teachers and parents were comfortable with their roles, and answered questions.
The age range of students did not present a problem for the instructors, because each program was tailored to the abilities of each group of students. Most of the students were in grades five through seven; however, one second grade and one high school class took part in the program. For the younger grades, the handouts and explanations were simplified. The hands-on activities were successfully completed at all age levels, and only the discussion had to be made age-appropriate. The activities were designed with fifth graders in mind, but were found to be effective for grades fourth through high school without major changes. Except for the cardiovascular module, students had not done any of the activities before the program. The subject matter of exercise and nutrition and its effect on their bodies was personal and interesting to most of the students. Every age group from second graders to high school seniors was interested in their own lung capacity, heart rate, skin temperature, and energy expenditure. The oxygen uptake module, which was interesting for all students, was very useful for the high school students. This module examined energy usage during different intensities of exercise and also allowed for discussion of questions dealing with research, such as those dealing with experimental design, which could be answered through individual demonstrations.
The web site, while mostly written before the start of the park program, still needed updating each day, which became too time intensive for the instructors. The web site was initially meant to be used as an extension of the off-campus/park program, allowing students to participate in the 10-day event. When asked about the use of the web page, teachers either had not accessed the site or had problems accessing the site. A simpler site, with pretraining of the teachers on its use, may have made the site more useful and more worth the time that was spent on it.
Student evaluations of the program were not obtained; therefore, the program may have been improved with the use of pre- and postcompetency tests. We would also have a better measurement of the effectiveness of the program if students and volunteers had performed written evaluations and if we had a better return rate on evaluations from teachers.
In conclusion, from the conversations that occurred during and after the programs with teachers, students, and parent volunteers and from the teachers’ written evaluations, it was apparent that the students gained new insights into how their bodies function and why physical activity is needed to remain healthy. The program complemented and integrated both science and health curricula and was probably most effective at this in the fourth through seventh grades, the level for which the program was initially developed. The park program was a positive program as far as student learning and exposure to life science experiences.
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Acknowledgments |
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Received for publication June 12, 2003. Accepted for publication January 6, 2005.
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