Objective: This study sought to ascertain the energy expenditure (EE) associated with different sedentary and physically active free-play activities in primary school-aged children. Methods: Twenty-eight children (13 boys; 11.4±0.3 years; 1.45±0.09 m; 20.0±4.7 kg∙m-2) from one primary school in Northwest England engaged in six activities representative of children’s play for 10 minutes (drawing, watching a DVD, playground games and free-choice) and 5 minutes (self-paced walking and jogging), with 5 minutes rest between each activity. Gas exchange variables were measured throughout. Resting energy expenditure was measured during 15 minutes of supine rest. Results: Child (Schofield-predicted) MET values for watching a DVD, self-paced jogging and playing reaction ball were significantly higher for girls (p&#60;0.05). Conclusion: Utilising a field-based protocol to examine children’s free-living behaviours, these data contribute to the scarcity of information concerning children’s EE during play to update the Compendium of Energy Expenditures for Youth

Mackintosh, Kelly A.

Ridgers, Nicola D.

Ridley, Kate

Stratton, Gareth

Objective:This study sought to ascertain the energy expenditure (EE) associated with different sedentary and physically active free-play activities in primary school-aged children.Methods:Twenty-eight children (13 boys; 11.4 ± 0.3 years; 1.45 ± 0.09 m; 20.0 ± 4.7 kg·m-2) from 1 primary school in Northwest England engaged in 6 activities representative of children’s play for 10 minutes (drawing, watching a DVD, playground games and free-choice) and 5 minutes (self-paced walking and jogging), with 5 minutes rest between each activity. Gas exchange variables were measured throughout. Resting energy expenditure was measured during 15 minutes of supine rest.Results:Child (Schofield-predicted) MET values for watching a DVD, self-paced jogging and playing reaction ball were significantly higher for girls (P &lt; .05).Conclusions:Utilizing a field-based protocol to examine children’s free-living behaviors, these data contribute to the scarcity of information concerning children’s EE during play to update the Compendium of Energy Expenditures for Youth.</jats:sec

Kelly A. Mackintosh

Kate Ridley

Gareth Stratton

Nicola D. Ridgers

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Journal of Physical Activity and Health

Energy Cost of Free-Play Activities in 10- to 11-Year-Old Children

Kelly Mackintosh

Cronfa at Swansea University

 Cronfa -  Swansea University Open Access Repository   _____________________________________________________________   This is an author produced version of a paper published in :Journal of Physical Activity and Health                                              Cronfa URL for this paper:http://cronfa.swan.ac.uk/Record/cronfa27985_____________________________________________________________ Paper:Mackintosh, K. Energy cost of free-play activities in 10-11 year old children. Journal of Physical Activity and Health        _____________________________________________________________  This article is brought to you by Swansea University. Any person downloading material is agreeing to abide by theterms of the repository licence. Authors are personally responsible for adhering to publisher restrictions or conditions.When uploading content they are required to comply with their publisher agreement and the SHERPA RoMEOdatabase to judge whether or not it is copyright safe to add this version of the paper to this repository. http://www.swansea.ac.uk/iss/researchsupport/cronfa-support/  Energy	Cost	of	Free-Play	Activities		 1  Energy cost of free-play activities in 10-11 year old children 1  2 Brief Running Head: Energy Cost of Free-Play Activities  3  4  5 Key Words: Youth, Physical activity, measurement  6  7 Manuscript Type: This submission is for the 2016 NCCOR supplement 8  9 Abstract word count: 144 words 10  11 Manuscript word count: 1945 words  12  13 Date of manuscript submission: 22/03/2016  14 Energy	Cost	of	Free-Play	Activities		 2  Abstract 15 Objective: This study sought to ascertain the energy expenditure (EE) associated with 16 different sedentary and physically active free-play activities in primary school-aged children. 17 Methods: Twenty-eight children (13 boys; 11.4±0.3 years; 1.45±0.09 m; 20.0±4.7 kg·m-2) 18 from one primary school in Northwest England engaged in six activities representative of 19 children’s play for 10 minutes (drawing, watching a DVD, playground games and free-20 choice) and 5 minutes (self-paced walking and jogging), with 5 minutes rest between each 21 activity. Gas exchange variables were measured throughout. Resting energy expenditure was 22 measured during 15 minutes of supine rest. Results: Child (Schofield-predicted) MET values 23 for watching a DVD, self-paced jogging and playing reaction ball were significantly higher 24 for girls (p<0.05). Conclusion: Utilising a field-based protocol to examine children’s free-25 living behaviours, these data contribute to the scarcity of information concerning children’s 26 EE during play to update the Compendium of Energy Expenditures for Youth.  27 Energy	Cost	of	Free-Play	Activities		 3  Introduction 28 In 2008, Ridley and colleagues1 developed the Compendium of Energy Expenditures for 29 Youth to enable researchers to understand the energy costs associated with commonly 30 performed activities during daily living. However, two-thirds of the information listed was 31 estimated using the adult compendium.2 The compendium should be based on measured 32 child-specific energy costs during both structured and unstructured activities across the 33 intensity spectrum (i.e., sedentary, light, moderate, vigorous). However, the majority of 34 previous research utilised highly structured protocol’s to assess children’s EE to standardise 35 movement patterns and facilitate inter-individual comparisons. Such laboratory-based 36 protocols may be limited in the assessment of free-living behaviours.3 For example, the 37 energy cost of pre-determined treadmill and/or running speeds are often examined, yet may 38 have little ecological validity as these behaviours are self-paced by individuals and performed 39 over-ground during daily living. In addition, given the sporadic and intermittent nature of 40 children’s physical activity (PA) there is a need to establish children’s EE during play, with 41 greater autonomy over mode, duration and intensity, which is more representative of their 42 free-living behaviours. Unstructured free-play and playground games are examples of 43 common behaviours children engage in, both at school and after school,4 yet data on active 44 free-play that informed the 2008 compendium were scarce. Indeed, the “unstructured outdoor 45 play” MET value was based on one study that measured school quadrangle play in the 1920s. 46 The aim of this study was to ascertain the EE associated with different sedentary and 47 physically active free-play activities in children.  48  49 Methods 50 Study Participants 51 Energy	Cost	of	Free-Play	Activities		 4  Twenty-eight 10-11 year old children (13 boys, 15 girls) from one primary school in 52 Northwest England participated in the study. Descriptive characteristics are shown in Table 1. 53 Participants provided written assent and the primary caregiver provided informed written 54 consent. The study was approved by the University Ethics Committee.  55  56 Activities 57 Resting energy expenditure (REE) was measured during 15 minutes of supine rest in a quiet, 58 dimly lit room after at least one hour of fasting. Children subsequently took part in six 59 different activities chosen to represent intermittent and continuous behaviours undertaken in 60 free-play situations both on their own and with other people. The activities took place either 61 in the classroom or in the school playground in a randomised order, with five minutes of 62 seated rest between each activity. The six free-play activities that children participated in 63 were: 64  65 a) Drawing/colouring: The child sat at a classroom table and was provided with 66 materials to draw/colour pictures on their own; 67 b) DVD watching: The child sat inside the classroom and watched a DVD on their own; 68 c) Self-paced brisk walking: The child briskly walked around a marked circular track on 69 the playground at a self-selected pace; 70 d) Self-paced jogging: The child jogged around the marked circular track at a self-71 selected pace;  72 e) Playground games: The child played three different games in a standardised order 73 (hopscotch, Frisbee, and reaction ball) for 3.3 minutes each on the playground with a 74 researcher, with no breaks in between; 75 Energy	Cost	of	Free-Play	Activities		 5  f) Free choice games: The child was provided with the opportunity to play different 76 games on their own or with a researcher. A Frisbee, soccer ball, tennis racquets and 77 balls, skipping ropes, hula hoops, reaction ball, and a large dice were provided to 78 facilitate the games. The child was able to freely change the game(s) played during 79 this time.  80  81 All activities were 10 minutes in duration, with the exception of self-paced brisk walking 82 and self-paced jogging which were 5 minutes in length. This was to ensure that children 83 could sustain the self-selected pace for the whole activity duration.   84  85 Outcome Measures 86 EE was assessed using a portable, open-circuit indirect calorimetry system (MetaMax 3B, 87 Cortex, Leipzig, Germany) that measured breath-by-breath oxygen consumption (VO2). The 88 MetaMax was calibrated before each trial using the manufacturer recommended procedure. 89 Respiratory volume was calibrated using a 3-L syringe. Gas sensors were calibrated against 90 known concentrations of gases (16% oxygen, 4% carbon dioxide). The MetaMax analyser 91 unit was attached to the child around their upper body using a paediatric harness with 92 adjustable Velcro straps. A facemask was secured over the child’s nose and mouth using an 93 adjustable nylon harness. A bi-directional digital turbine flow meter was inserted into the 94 facemask to measure the volume of inspired and expired air. A sample line connecting the 95 turbine and analyser unit to determine the content of oxygen and carbon dioxide. Data were 96 retrieved at the end of each trial for analysis by manufacturer proprietary software (MetaMax, 97 version 2.4, Statera Edition). Data were reduced to 10 second epochs for analysis due to the 98 free-play nature of the activities being performed.  99 Energy	Cost	of	Free-Play	Activities		 6  REE was calculated by removing the first five and last minutes and averaging the 100 remaining data during the resting phase. For each activity VO2 (l·min-1), relative VO2 (ml·kg-101 1·min-1) and EE (J·kg-1·min-1) were calculated by removing the first 2.5 minutes and last 0.5 102 minute and averaging the remaining data. As children can achieve steady state in 2-3 103 minutes5, the individual playground games (hopscotch, Frisbee and reaction ball) were also 104 examined separately. For these activities, the first 2.5 minutes were removed and an average 105 across 50 seconds. After 2.5 minutes, EE values had reached steady state which was indicated 106 by a plateau in VO2 and VCO2 where values varied by less than 15%. VO2 was converted to 107 EE using the values of 1L O2 = 4.9 kcal.6 All participants were assessed with the same 108 calorimeter.  109 An estimate of daily RMR was calculated for each participant using the sex- and age- 110 and mass- specific Schofield prediction equations.7 Child metabolic equivalents (Child 111 METs) were calculated by dividing activity EE by predicted RMR.7 112  113 Statistical Analyses 114 All data are expressed as means and standard deviations. One-way analyses of variance were 115 conducted to examine sex differences for the descriptive characteristics and the energy cost 116 of the free-play activities. All statistical analyses were conducted using PASW Statistics 22 117 (SPSS, Chicago, Il). Statistical significance was set at p<0.05. 118  119 Results 120 Technical issues with the MetaMax, resulted in three children’s data (one boy, two girls) 121 being fully lost. Incomplete data were recorded for eight children (two boys, six girls). All 122 collected data were analysed for each activity. The energy cost of the sedentary and active 123 Energy	Cost	of	Free-Play	Activities		 7  free-play behaviours, along with the sample sizes for each behaviour, are shown in Table 2 124 and Table 3, respectively.  125 There were no significant sex differences for any of the descriptive characteristics. 126 Self-paced walking and jogging speeds were 1.71 ± 0.1m·s-1 (range 1.31-2.00m·s-1) and 2.59 127 ± 0.32m·s-1, (range 1.31-2.00m·s-1) for the whole sample, respectively. Specifically, boys and 128 girls speeds were 1.65 ± 0.2m·s-1 (1.31-2.00m·s-1) and 1.86 ± 0.1m·s-1 (1.55-1.97m·s-1) for 129 walking, and 2.5 ± 0.4m·s-1 (1.91-2.96m·s-1) and 2.67 ± 0.3m·s-1 (2.19-3.3m·s-1) for jogging, 130 respectively.	 In line with the adult compendium, the energy cost associated with various 131 speed ranges (1.31-1.80m·s-1, 1.81-2.30m·s-1, 2.31-2.80m·s-1 and 2.81-3.30m·s-1) are shown 132 in Table 3. Girls expended more energy than boys for drawing (p<0.05). Child MET values 133 for watching a DVD, self-paced jogging and playing reaction ball were significantly higher 134 for girls (p<0.05).  135  136 Discussion 137 The activity that was least consistent with the 2008 compendium was self-selected brisk 138 walking, which has been used to describe moderate-intensity PA (MPA) in public health 139 recommendations. On average, children walked at 1.7m·s-1, which was 0.2m·s-1 faster than 140 the identified ‘hard’ speed,1 and elicited an EE of ≥4 METs. Notably, 4 METs is increasingly 141 used to quantify children’s MPA in accelerometry studies,8 which this study supports. For 142 jogging, children self-selected a speed that was consistent with moderate running in the 143 compendium, though the energy cost was closer to the MET value identified for light 144 jogging.1 Despite this discrepancy, self-paced jogging exceeded the vigorous-intensity PA 145 (VPA) threshold of 6 METs, which is typically used to quantify children’s VPA in 146 accelerometry studies.8 147 Energy	Cost	of	Free-Play	Activities		 8  Little data were available to identify the energy cost of unstructured outdoor play in 148 the original compendium.1 Using a protocol where children had autonomy over the intensity 149 they engaged in to play the different playground games, which were sporadic and intermittent 150 in nature, the energy cost was consistent with the original 5 METs value. This is a positive 151 finding and further supports the inclusion of active play as an example of PA in current 152 recommendations.9 One of the playground games children played during this condition was 153 Frisbee, which was an activity where the energy cost was estimated using adult data.2 This 154 study provides new information about the energy cost of this activity during unstructured 155 playground games for children, which on average had an average energy cost of ~5.5 METs.  156 There has been some recent debate about the classification of sedentary behaviour in 157 children, and whether a threshold of ≤1.5 or ≤2 METs should be used.10 On average, both 158 drawing and DVD watching had energy costs that were consistent with the ≤1.5 MET 159 threshold, though there was some variability in individual values, and the current values 160 within the youth compendium.1 It is postulated that reaching for different materials provided 161 will have resulted in small body movements equivalent to sit-stand transitions, which may 162 have increased the energy cost of the activity.11  163 This study utilised a field-based protocol to examine the energy cost of children’s 164 free-living behaviours. These data contribute to the scarcity of information concerning 165 children’s EE during play.  166  167 Acknowledgements 168 The authors would like to thank all of the children who participated in the study and Kate 169 Eccles for her help during data collection.  170  171 Funding Source  172 Energy	Cost	of	Free-Play	Activities		 9  This work was supported by an Institute for Health Research award.  173   174 References 175 1. Ridley K, Ainsworth BE, Olds TS. Development of a compendium of energy 176 expenditures for youth. Int J Behav Nutr Phys Act. 2008;5:45. 177 2. Ainsworth BE, Haskell WL, Whitt MC, et al. Compendium of physical activities: an 178 update of activity codes and MET intensities. Med Sci Sports Exerc. 179 2000;32(9):S498-S516. 180 3. Nilsson A, Brage S, Riddoch C, et al. Comparison of equations for predicting energy 181 expenditure from accelerometer counts in children. Scand J Med Sci Sports. 182 2008;18(5):643-650. 183 4. Stanley RM, Ridley K, Olds TS. The type and prevalence of activities performed by 184 Australian children during the lunchtime and after school periods. J Sci Med Sport. 185 2011;14(3):227-232. 186 5. Rowland TW. Developmental Exercise Physiology. Champaign, IL: Human Kinetics; 187 1995. 188 6.  McArdle WD, Katch FI, Katch VL. Exercise Physiology: Nutrition, Energy, and 189 Human Performance (7th Ed). Philadelphia: Lippincott Williams & Wilkins; 2010. 190 7. Schofield WN. Predicting basal metabolic rate, new standards and review of previous 191 work. Hum Nutr Clin Nutr. 1985;39 Suppl 1:5-41. 192 8. Trost SG, Loprinzi PD, Moore R, Pfeiffer KA. Comparison of accelerometer cut-193 points for predicting activity intensity in youth. Med Sci Sports Exerc. 194 2011;43(7):1360-1368. 195 9. Department of Health. Everybody Active, Every Day. An evidence-based approach to 196 physical activity London: Department of Health; 2014. 197 Energy	Cost	of	Free-Play	Activities		 10  10. Saint-Maurice PF, Kim Y, Welk GJ, Gaesser GA. Kids are not little adults: what 198 MET threshold captures sedentary behavior in children? Eur J Appl Physiol. In press. 199 11. Júdice PB, Hamilton MT, Sardinha LB, Zderic TW, Silva AM. What is the metabolic 200 and energy cost of sitting, standing and sit/stand transitions? Eur J Appl Physiol. In 201 press. 202 

Energy Cost of Free-Play Activities in 10- to 11-Year-Old Children

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