INTRODUCTION

The growing burden of disease associated with excess weight in the paediatric population, along with the increase in sedentary lifestyles, may lead to the collapse of many health systems worldwide, in addition to producing significant suffering and costs in affected individuals. ^{1 2}

The extent of the burden of disease is due, on one hand, to the considerable prevalence of excess weight, of more than 40% in the pre-adolescent population of countries such as Spain³ and with significant variations based on geographical area and social variables, ^{4 5} and, on the other hand, to the high morbidity and mortality resulting from the combination of obesity with sedentary habits, which is a risk factor for cardiovascular disease, metabolic syndrome, diabetes, orthopaedic, respiratory and psychological problems, and is also associated with a lower life expectancy.^{6-8 7 8} Obese children have a poor self-image and express feelings of inferiority and social rejection, and are at high risk of depression and anxiety. ^{9 10 11}.

This problem is difficult to resolve once it has developed, and there is a clear correlation between overweight and obesity in childhood and in adulthood.^7,12.¹²

The World Health Organization,¹ health authorities and scientific associations have raised an alarm and proposed countless recommendations, guidelines, strategies and consensus documents for the treatment of what is by now considered a serious and significantly challenging epidemic.^{13 14 15 16 17} In Spain, the Strategy for Nutrition, Physical Activity and the Prevention of Obesity was launched 2005.¹⁸ Its aim is to raise awareness in the community of the problems associated with obesity and to promote every possible intervention that may contribute to the development of healthy dietary habits and regular physical activity, especially in children and youth.

Obesity continues to be one of the most challenging problems in everyday clinical practice. There is evidence that interdisciplinary interventions for treatment of obesity in children and adolescents with the collaborative and coordinated involvement of professionals from different fields (psychologists, fitness and sports professionals, nutritionists, physicians) are more effective than interventions based on a single approach. ^{19 20 21 22 23}

The current clinical practice guidelines for the management of child and adolescent obesity recommend the development of community-based programmes to promote healthy lifestyles, a healthy diet, and the practice of physical activity.^{13 15 16 17}

One of the most significant challenges that arises is the lack of adherence to treatment and prevention programmes. This is related to the difficulty in gaining the motivation necessary to change lifestyle habits. ^{21 22 23 24}

When it comes to fostering the habit of exercising in children, it is essential to make physical activity fun. Many aspects of outdoor bicycle riding may further this goal. In addition to its association with exercise, bicycles have always been desirable toys for children. It promotes autonomy in everyday travelling and environmental awareness, as it does not cause pollution.²⁵

Studies on the effects of bicycle riding interventions on cardiovascular health and the prevention and treatment of excess weight and the associated comorbidities have focused on the daily commute to work in adults or to school in children. ^{26 27 28 29 30 31 32 33 34 35 36} There is solid evidence that programmes that promote daily bicycle riding offer benefits that far outweigh the risks. -^{37 38 39 40 41 42 43 44}

On the foundation of the recommendations of the guidelines and strategies mentioned above, we developed a multidisciplinary programme called Bicisalud (“Bikehealth”) based on group bicycle rides through nature combined with practical workshops on how to develop healthy lifestyles. The aim of our study was to assess the impact of this programme on the physical skills and body composition of schoolchildren with excess weight, as well as on their physical self-perception and their dietary and exercising habits.

MATERIALS AND METHODS

We conducted a quasi-experimental study with assessment of outcome variables pre and post intervention (Fig. 1). The study took place between summer 2015 and summer 2017 in Colmenar Viejo, a town with 48 000 inhabitants north of Madrid in an area with an extensive network of country roads and a low volume of motor vehicle traffic, which allows their use for both agricultural use and recreational exercise on foot or on bicycle. The first summer, before starting the programme, we contacted local and regional health care institutions to make the project known and to obtain the approval of the competent ethics committee.

IC: informed consent (13 did not meet the inclusion criteria and did not advance to T0); N: sample; T0: measurement of dependent variables at baseline; T1: at the time intervention ended; T2: three months after the intervention

Figure 1. Flow chart of the project (2015-17) 

Sample: the inclusion criteria for the programme were: age 8 to 14 years, body mass index (BMI) at or above the 90^th percentile based on the growth tables of the 1988 study by Hernández et al., knowing how to ride a bicycle, and parental authorization through signing of an informed consent form. The exclusion criteria were: chronic or subacute underlying disease where physical activity is contraindicated, concurrent participation in other fitness programmes, or current pharmacological or surgical treatment for obesity.

Since gathering a group of volunteers proved difficult, we implemented an intensive informational campaign in the fall-winter season: in the primary care centres of the area; in the community, with the support of the authorities, by hanging posters and distributing flyers printed by the city council in mailboxes (5000 flyers and 80 posters) (Fig. 2); in the local press and radio stations; in pharmacies, recreational centres, and in schools, visiting the classrooms and using that opportunity to provide education on healthy lifestyle habits to more than 2400 students over the two seasons. Based on the available resources and taking into account potential losses to followup, we decided that we needed to have a group of 45 participants.

Design: Antonia Matorrales (Casa de la Juventud)

Figure 2.  Sample of the poster printed by the City Council of Colmenar Viejo 

RESULTS

Of the 60 applicants (26 in 2016 and 34 in 2017) for who we obtained informed consent for participation in Bicisalud, 47 met the inclusion criteria (25 + 22) and, after measurement of the primary and secondary outcome variables at baseline (T0), started the programme of activities that run through two springs with a flexible calendar of outings and workshops that were scheduled as the programme advanced. The mean age at initiation of the programme was 11.2 years (SD, 1.52); 57.45% of participants were male, and 42.55% female. The median number of events that participants attended was 16 (interquartile range: 11-19).

Fig. 1 shows the sample at each time point (T0, T1, T2), illustrating the losses to followup. Table 2 provides a descriptive summary of the variables under study. The purpose of this table is merely to document the impact of the losses to followup, as the corresponding data had to be removed from the analyses presented in Tables 3 and 4.

These tables present the results of the statistical analysis of the subset of participants that completed the programme, that is, the 27 children (44.5% male and 55.5% female) assessed at all 3 time points, although one of the girls missed one fitness assessment.

With the exception of the physical self-perception and Kreceplus-physical activity scores, we found differences in the means of all other variables at some point.

When we compared the moment when the intervention had just ended (T1) with baseline (T0), we found increases in strength, aerobic endurance, flexibility and height, and a decrease in waist circumference. However, when we compared the time point at 3 months post intervention (T2) with the end of the intervention (T1), we found decreases in aerobic endurance and the Kreceplus-Nutrition score, as well as increases in weight, BMI (and BMI z-score) and waist circumference; the height also continued to increase. The changes observed between the T0 baseline time point and T2 were increases in flexibility, weight and height.

In short, implementation of the programme was associated with a significant and rapid improvement in the primary endpoint (physical fitness), which was not sustained through the three months of the summer holidays except for flexibility, which remained improved in most of participants. The changes found in other variables were not statistically significant.

During the two periods of scheduled activities (three months/participant), there were only a few falls and minor accidents, and none of them resulted in significant injury or changes in participation.

We ought to mention that the development of the Bicisalud programme provides an example of an interactive intervention with very positive aspects—albeit not measurable ones—involving the collaboration of primary care settings, elementary and secondary schools, sports organizations, paediatric participants and their families, recreational counsellors and cultural, social and environmental groups in the context of what has been come to be known as social health promotion networks.⁴⁹

This experience has led to the allocation of funds in the town council budget for the implementation of a new Bicisalud programme in the next season, which this time will be open to all schoolchildren regardless of their BMI.

DISCUSSION

Bicisalud succeeded in improving the physical fitness of participating children, fulfilling its primary objective, although these gains were short-lived. The effect of the programme disappeared in the followup assessment performed after the summer holidays, except for flexibility, which continued to be significantly better compared to baseline.

When we asked participants about the activities they had engaged in during summer and specifically about bicycle riding or other types of exercising, most replied that they had for the most part remained inactive during summer and that they had only used their bicycle occasionally.

This is consistent with the considerable increase of sedentary habits worldwide, which is one of the key aetiological factors in the growing epidemic of excess weight and its deleterious consequences. ^{50 51 52} It is clear that children are being entertained at increasingly early ages with activities such as hypnotically watching the smartphones of their parents, until they get one of their own, also increasingly early. This is why the Bicisalud programme, while having other components, focuses on the promotion of active and fun leisure activities involving bicycle riding with peers of similar characteristics.

The decreases achieved in some of the secondary outcome variables, such as the BMI, which may be the most socially desirable goal, were not statistically significant and were not sustained through the summer holidays. On the other hand, along the same lines, there was a statistically significant improvement in waist circumference, which is also an indicator of excess body fat, even if it had returned to baseline during the relatively inactive summer. Other authors have reported similar difficulties in pursuing these goals with interventions of broader scope ^{21 23 28 51 53}

We also found moderate improvements in physical self-perception that did remain after summer, although the differences were not significant at any point. Low self-esteem is an important associated problem in children with overweight or obesity, which is both cause and effect of them, and while improving it was only a secondary objective in our programme, we would have wanted to find a more consistent improvement in this variable. ^{9 10 11}

The areas where Bicisalud achieved the least favourable results were dietary and physical activity habits, assessed by the validated and well-known Kreceplus questionnaires. -^{19 21 24 48} A possible explanation of the ineffectiveness of the programme on these areas could be that achieving even small changes in lifestyle habits requires more intensive and longer-lasting interventions through various channels of communication, especially when the change requires the involvement of the entire family. We also need to take into account social pressure factors that facilitate sedentary leisure activities and deplorable dietary habits.⁵⁴

The recruitment of participants was one of the main barriers to the success of the Bicisalud project. It is not easy for children with excess weight to take the initiative of enrolling and thus acknowledge their problem openly in the community. Due to this difficulty, we had to conduct the study over two different periods to achieve the necessary sample size. On the other hand, the efforts required to overcome this challenge resulted in increased cohesion and enthusiasm in the group of children and collaborators.

Despite the fun and adventurous nature of each ride and the variety of the activities and the people involved, which helped add interest to the programme, there were significant losses to followup that may have affected the final results.

In conclusion:

APPENDICES

We have added three appendices that are available in the webpage of the journal: