Journal of Sports Sciences, March 2005; 23(3): 269 – 275
Physical activity and school recess time: Differences between the sexes and the relationship between children’s playground physical activity and habitual physical activity
´ CARLOS RIBEIRO, JORGE MOTA, PEDRO SILVA, MARIA PAULA SANTOS, JOSE JOSE´ OLIVEIRA, & JOSE´ A. DUARTE Research Centre for Physical Activity, Health and Leisure, Faculty of Sport Sciences and Physical Education, University of Porto, Porto, Portugal (Accepted 1 August 2004)
Abstract The aims of this study were: (1) to observe participation in moderate-to-vigorous physical activity (MVPA) during school recess periods; (2) to determine the relative importance of physical activity during recesses to overall daily physical activity; and (3) to examine differences in physical activity between the sexes during unstructured recess periods. The participants were 22 school children (10 boys, 12 girls) aged 8 – 10 years (mean = 8.9, s = 0.7) in the third and fourth grades. Daily totals for the physical activity variables were calculated by summing the values for each hour of 14 h of physical activity measurements (08:00 to 22:00 h). Recess times (minutes) were as follows: morning 10:30 to 11:00 h and afternoon 15:30 to 16:00 h. We did not differences between boys and girls in daily total accelerometer counts or the overall time spent in MVPA. However, girls were significantly (P 5 0.05) more involved (38%) in MVPA during recess time than boys (31%). Participation in MVPA during recess contributes significantly more (P 5 0.05) for girls (19%) than boys (15%) to the total amount of physical activity suggested by international health-related physical activity guidelines, while the percentage of time engaged in MVPA during recess time at school accounts for a small amount of the daily MVPA (6% for boys and 8% for girls). The results of this study suggest that school recess time is an important setting to promote MVPA and contributes to daily physical activity in young children, especially in girls.
Keywords: Children, gender, playground, physical activity
Introduction Children’s physical inactivity has been categorized as a modifiable risk factor for lifestyle-related diseases and many of the known risk factors for chronic diseases are also presented in youth (Raitakari et al., 1997; Teixeira, Sardinha, Going, & Lohman, 2001). Furthermore, it has been suggested that physical inactivity during youth is linked to several healthrelated risks in adulthood (Twisk, Mellenbergh, & Van Mechelen, 1997). From a health promotion perspective, it makes sense to ensure that people are sufficiently physically active from a young age (Van Mechelen, Twisk, Post, Snel, & Kemper, 2000). General guidelines are widely adopted to describe health-related physical activity benefits in youth. These guidelines, which address the important role played by moderate-to-vigorous physical activity (MVPA), recommend that children should be
engaged in continuous or intermittent bouts of MVPA for an optimum of 60 min each day (Cavill, Biddle, & Sallis, 2001; Corbin & Pangrazi, 1998). Despite the fact that most physical activity by children is undertaken outside of the school environment (Sallis et al., 1993; Vicent & Pangrazi, 2002), schools have long been recognized as key settings both to promote and to contribute to physical activity guidelines because children spend a large proportion of their time there (Biddle, Sallis, & Cavill, 1998; Iverson, Fielding, Crow, & Christenson, 1985). There are two main times within the school day during which children have the opportunity to be physically active – physical education lessons and playground recesses (Stratton, 2000). Perhaps the most common school context in which children have the opportunity to be physically active is during primary school recess (Zask, Van Beurden, Barnett, Brooks, & Dietrich, 2001). In fact, play-
Correspondence: J. Mota, CIAFEL-FCDEF/UP, R. Pla´cido Costa 91, 4200-450 Porto, Portugal. E-mail:
[email protected] ISSN 0264-0414 print/ISSN 1466-447X online # 2005 Taylor & Francis Group Ltd DOI: 10.1080/02640410410001730124
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grounds represent a context in which children can engage in physical on a daily basis for most of the calendar year (Stratton & Leonard, 2002). School playgrounds highlight the problem of children’s physical inactivity. Indeed, a structured environment such as the school setting might constrain activity levels during the school day, and limit the individual variability that can occur during school hours (Vincent & Pangrazi, 2002). Recess periods are unstructured, thus allowing children to spontaneously engage in physical activity (Johns & Ha, 1999; Sarkin, McKenzie, & Sallis, 1997). Recent evidence suggests that young children accumulate more time spent in physical activity during unstructured play environments, where they are more likely to participate in MVPA (Pate, Baranowski, Dowda, & Trost, 1996). Furthermore, several studies have reported differences in physical activity levels among boys and girls in different settings and populations (Sallis, Prochaska, & Taylor 2000; Trost, Pate, Freedson, Sallis, Taylor, 2000). Boys are reported to be significantly more involved in MVPA than girls (Santos, Guerra, Ribeiro, Duarte, & Mota, 2003; Trost et al., 2002). Moreover, during the school day, playtime represents the main context in which girls and boys have an equal opportunity to be physically active on a daily basis (Sarkin et al., 1997). However, limited attention has been paid to differences between the sexes during recess time at school as well as the contribution that primary school playtime can make to overall daily MVPA in children. We hypothesized that school playgrounds can offer a good opportunity to enhance MVPA participation, especially among girls. The aims of this study were: (1) to observe participation in moderate-to-vigorous physical activity during school recess periods; (2) to determine the relative importance of physical activity during recesses to overall daily physical activity; and (3) to examine differences in physical activity between the sexes during unstructured recess periods.
Methods Participants and setting The participants were 22 school children (10 boys, 12 girls) aged 8 – 10 years (mean = 8.9, s = 0.7) in the third and fourth grades. Mean height was 1.36 + 0.07 m and 1.39 + 0.03 m for boys and girls respectively. Mean body mass was 34.2 + 6.9 kg and 35.9 + 6.3 kg for boys and girls respectively. These values were within the normal ranges for Portuguese children of this age (Guerra, Duarte, & Mota, 2001). The average daily monitoring times were 13.7 + 0.9 h for boys and 13.9 + 1.4 h for girls, which are similar to those previously described for a similar population (Santos et al., 2003).
The surface of the school playground was made of cement with small areas of sand. The area of the playground was approximately 60 6 15 m. There was no visible playground equipment (e.g. seesaw or slides) or markings to stimulate play. Children were allowed to take small balls into the playground, but there was little evidence of any other equipment being used or being made available. Informed written consent was obtained from the children’s parents and the school principal and the study was approved by the Ministry of Science and Technology. Objective measure of daily physical activity The accelerometer (model CSA 7164, Computer Science Applications Inc., Shalimar, FL) activity monitor was used as an objective measure of daily physical activity. The uni-axial CSA accelerometer is a small (5.1 6 4.1 6 1.5 cm), lightweight (42.5 g) single-channel accelerometer designed to measure and record acceleration ranging in magnitude from 0.05 to 2.00 g with a frequency response from 0.25 to 2.50 Hz. The filtered acceleration signal is digitized and the magnitude is summed over a user-specified period of time (an epoch interval). At the end of each epoch, the summed value is stored in memory and the numerical integrator is reset. This process can repeat itself for 22 consecutive days, if a 1-min epoch is used, before the memory is filled. Using a reader interface unit connected to a computer it is possible to download the recorded data and, using the software supplied with the unit, analyse the data. It has previously been reported that there is a highly significant correlation between physical activity recorded by the accelerometer and energy expenditure assessed by indirect calorimetry, and that there is a high degree of inter-instrument reliability (Janz, Witt, & Mahoney, 1995). It has been reported that during laboratory exercise there is a high correlation (r = 0.86) between accelerometer recordings and energy expenditure (Trost et al., 1998); however, others have questioned whether this level of precision can be reproduced during free-living activities (Harro & Riddoch, 2000). Since children are likely to engage in activities that involve bending, jumping, running and throwing on a daily basis, measurement tools should be validated for use with such activities (Ott, Pate, Trost, Ward, & Saunders, 2000). Field studies have shown that both uni-axial (CSA) and multi-axial (Tritrac) accelerometers are appropriate for measuring children’s free play physical activities (Coe & Pivarnick, 2001; Eston, Rowlands, & Ingledew, 1998). The procedure for measuring daily physical activity in this study had previously been used successfully in a paediatric population from the same location (Mota et al., 2002).
Physical activity during recess time Protocol The study was conducted on three consecutive schooldays (Tuesday to Thursday) between May and June 2000. Before each test period and for every child, the activity monitors were tested. For the present study, the epoch duration or sampling period was set at 1 min and the output was expressed as counts per minute (counts × min – 1). The accelerometer was placed in a small nylon pouch and firmly adjusted at the child’s waist by an elastic belt over the non-preferred hip. A data sheet was given to the children’s parents, who were instructed to record the time when the monitor was attached in the morning and detached in the evening. They were also instructed to note every time the child performed any restricted activities like showering and swimming. Data reduction Daily totals for the physical activity variables were calculated by summing the values for each hour of 14 h of physical activity measurements (08:00 to 22:00 h). Recess times (minutes) were as follows: morning 10:30 to 11:00 h and afternoon 15:30 to 16:00 h. For the purposes of this study, only the total counts provided by the accelerometer were used in the analysis. Counts from the accelerometer were averaged to determine the mean count per minute for the intensity of each physical activity. Therefore, the physical activity variables were expressed in counts per minute (activity counts divided by minutes of monitored activity). The daily time spent in MVPA ( 4 3 MET) was calculated by summing the minutes of moderate, vigorous and very vigorous physical activity for each day. The age-specific count ranges corresponding to the intensity levels were derived from the energy expenditure prediction equation (r = 0.94; standard error of the estimate = 1.19) developed by Freedson, Sirard and Debold (1997) for a paediatric population. This equation accounted for 90% of the variance in observed MET levels and predicted energy expenditure during treadmill running and walking within + 1.1 METs. This procedure has previously been used in other populations (Trost et al. 2000, 2002) and similar cultural context (Guerra et al., 2003). Statistical procedures Total daily physical activity (mean + s) and time spent in MVPA were calculated. The non-parametric Mann-Whitney U-test for two independent samples was used to determine differences between the sexes. The chi-square test of independence was used to examine differences between the sexes in the proportion of time spent in MVPA. Statistical
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significance was set at P 4 0.05. All statistical analyses were performed using SPSS 10.0 for windows. Results The activity levels of boys and girls are presented in Table I. There were no statistically significant differences in daily accelerometer counts, recess time accelerometer counts, MVPA (min × day71) or recess time MVPA (min) between boys and girls. Figure 1 shows the daily pattern of physical activity for boys and girls combined. Periods containing a school recess (10:30 to 11:00 h and 15:30 to 16:00 h) were the periods with the highest total activity. The period after the school day (17:00 to 20:00 h) was also important in terms of the amount of activity performed. Figure 2 shows the percentage of recess time spent in MVPA according to total recess time, healthrelated physical activity guidelines and total daily physical activity observed. The proportion of time (38%) that girls spent in MVPA during recess time was significantly higher (P 5 0.05) than that of the boys (31%). Participation in MVPA during recess contributes significantly more (P 5 0.05) for girls (19%) than boys (15%) to the total amount of physical activity suggested by international healthrelated physical activity guidelines. The percentage of time engaged in MVPA during recess time at school accounts for a small amount (6% for boys and 8% for girls) of the daily MVPA. Discussion The benefits of eradicating a sedentary lifestyle and promoting physical activity have become increasingly apparent for public health (Schmidt, Walkuski, & Stensel, 1998). Thus, enabling factors that allow children to be physically active are essential for successful health promotion strategies. Few studies have focused attention on the contribution of the primary school recess to health-related daily physical activity. Given that children spend some of their school day in recess, primary school playgrounds
Table I. Daily and recess time physical activity by gender (mean + s)
Daily accelerometer (counts × min71) Recess time accelerometer (counts × min71) MVPA (min × day71) Recess time MVPA (min)
Boys (n = 10)
Girls (n = 12)
542 + 266
479 + 216
914 + 642
1154 + 903
142 + ?80 9.2 + ?7.4
137 + ?72 11.4 + ?8.4
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Figure 1. Daily total physical activity (counts×min 7 1) per 60 min block (8:00 to 22:00)
Figure 2. Percent of recess time spent in MVPA according to, respectively, total recess time, health-related physical activity and total daily MVPA observed
provide an ideal setting for promoting children’s physical activity (Zask et al., 2001). Therefore, the primary school recess provides a rich context for the study and promotion of children’s physical activity. The present study examined differences in physical activity in unstructured school playtimes between boys and girls. Boys are generally accepted to be more active than girls at all ages (Sallis et al., 2000). However, our results showed that the girls performed a similar amount of physical activity as the boys during school recess periods. Although girls had higher mean values than boys for both total amount
of physical activity and time engaged in MVPA at recess, the results were not statistically significantly different. Our results contrast with previous findings showing that girls do not spontaneously engage in a large amount of MVPA at recess when compared with boys (Sarkin et al., 1997). Other studies in school settings found similar results to ours in terms of playground activities (Hovell, Bursick, Sharkey, & McClure, 1978). Boys and girls have also been found to engage in different types of activities (Faucette et al., 1995). Thus, from a behavioural perspective, the similar levels of physical activity between the girls
Physical activity during recess time and boys in the present study were likely a result of girls’ continued participation in traditional playground games, as described previously for a similar population (Stratton & Mota, 2000). The majority of boys spent much of their playtime in physically inactive play, swapping game cards or simply talking; this behaviour was occasionally interrupted by short bursts of activity. It has been proposed that differences in MVPA between the sexes are more apparent in an unstructured setting such as recess (Eaton & Enns, 1986). Our study offers no support for this finding, but rather supports the idea that school playgrounds can offer a good opportunity to enhance MVPA participation especially among girls, as previously suggested by Zask et al. (2001). Thus, school recesses are particularly important because differences in skill between the sexes typically increase in favour of boys over time (McKenzie et al., 2002). However, in young boys and girls, skill differences are generally determined by contextual rather than physiological factors (Thomas, Thomas, & Gallagher, 1993). Hence, cultural and environmental differences may also affect play activities (Sallis, Alcaraz, McKenzie, & Hovell, 1999). Thus it can be argued that the removal of an adult-controlled social context might partially explain the similar results obtained for girls and boys in this study. According to our data, school recess represented a good opportunity for children to accumulate physical activity over the day (Figure 1). However, whereas some children took this opportunity others did not, and significant individual differences in levels of physical activity were evident. In fact, we found large standard deviations in total counts per minute, suggesting wide individual variations in physical activity. This high variability in MVPA scores occurred during recess because children could freely choose to be sedentary or participate in physical activities of various intensities (Sarkin et al., 1997). This highlights the need to promote physical activity at the individual level during recess (Mota & Stratton, 1999). Some previous studies addressed the idea that the space afforded by school playgrounds provides a more ideal setting for children to engage in MVPA (Pate et al., 1996). These author’s study design included measurement of the percentage of time spent in MVPA. The results of our study indicated that boys spent 31% of recess time in MVPA, while girls spent 38% of recess time in MVPA (P 4 0.05). Although some studies have reported that children only spend 20% of school playtime in MVPA (Stratton & Leonard, 2002), others have shown that, given the opportunity of a play period, children will normally become engaged in MVPA rather than sedentary behaviours (Johns & Ha, 1999). Both
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Hovell et al. (1978) and Kraft (1989) found children to be engaged in MVPA for approximately 40% of recess time. More recently, Stratton (2000) showed that children on average accumulated 35 – 45% of their MVPA in primary school playgrounds, in line with our results. The amount of time spent in MVPA activities was approximately 142 minutes per day for boys and 137 minutes per day for girls. These values are similar to those reported by Sallis and Patrick (1994), who indicated that, on average, children engage in 0.4 – 0.7 h of vigorous and 0.5 – 1.5 h of moderate physical activity each day. The daily time spent in MVPA in the present study was also of the same magnitude as that reported previously in a similar paediatric population (Santos et al., 2003). The children in the present study appear to meet the minimum physical activity recommendations for health, in line with other surveys (Hussey, Gormley, & Bell, 2001; Sleap & Tolfrey, 2001). Playground participation in MVPA represented 19% and 15% of recommended health-related physical activity (at least 60 min) for girls (P 5 0.05) and boys respectively, contributing moderately to public health goals related to physical activity. Our results also highlight the importance of playtime physical activity as part of overall daily MVPA (6.5% for boys and 8.3% for girls). This suggests that increasing children’s active play may be important in enhancing MVPA participation as well as reaching healthrelated MVPA values. Further research should consider the lengthening of recess periods to increase physical activity levels (Zask et al., 2001). Some limitations of the study should be recognized. The study employed a small sample size and included students from one school only, which makes it difficult to generalize the findings. Nevertheless, the study focused on key periods or places that allow children to be active, as well as addressing physical activity levels and differences between the sexes during unstructured times using an objective measure, which enhances our confidence in the findings. Strategies to enhance children’s physical activity at school recess time must be developed. Future studies should attempt to develop our knowledge and understanding of the determinants of children’s health-promoting play during recesses. The present study indicates that both boys and girls engage in a moderate amount of MVPA during recess. Girls were as active as boys, which may be the result of an equal opportunity to play in this setting. Despite a low percentage of MVPA recess time with respect to total MVPA, recesses are important for following health-related physical activity guidelines. Our results support the idea that appropriate engagement in MVPA during recess time can make a significant contribution to recommended daily
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physical activity and has the potential to impact future practice in schools and increase the fitness of school children, especially girls.
Acknowledgements This study was supported by a grant from Fundac¸a˜o Calouste Gulbenkian (#48973/2001).
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