Inatividade física no lazer em jovens de Feira de Santana, Bahia

OBJETIVO: Estimar la prevalencia de inactividad fisica en el ocio entre los jovenes. METODOS: Estudio epidemiologico de corte transversal con muestra constituida por 1.400 jovenes entre 15 y 29 anos, residentes en el area urbana de Feira de Santana, Bahia (Brasil). Las actividades fisicas y de ocio fueron evaluadas por medio de un cuestionario estructurado, que abordo frecuencia, tipo, motivo y esfuerzo implicado. RESULTADOS: De los entrevistados, el 63,3% (n=795) eran inactivos fisicamente en su tiempo de ocio, siendo que la prevalencia fue mayor entre las mujeres (p<0,001) y entre los individuos en la franja de edad de 18-24 anos (p<0,001). CONCLUSIONES: La poblacion de jovenes residentes en el municipio de Feira de Santana, Bahia (Brasil), presento una prevalencia elevada de inactividad fisica en el ocio. Las politicas publicas destinadas a la promocion de salud de adolescentes y jovenes adultos deben priorizar acciones que faciliten que las mujeres y a los individuos de 18 a 24 anos se comprometan en practicas de actividades fisicas.


Introduction
Physical activity is defined as any bodily movement performed by skeletal muscles, resulting in a substantial increase in energy expenditure (1) .It can be understood as an essential quality of human beings, and it is an interdisciplinary topic which arouses the interest of investigators from several fields of knowledge, of the media and of public health.Hallal et al (2) highlight the fact that at no other time in history the practice of physical activities was so present in the public health agenda and in academic debate as in these last years.
The regular practice of physical activities is a protective behavior against the development of obesity, cardiovascular diseases, type II diabetes, cervical cancer (3) , and arterial hypertension (4) , also contributing to an improvement in the sense of wellbeing (5) .
In the last years, however, a substantial decrease in the population's level of physical activity can be noticed, especially during adolescence (6) .The decrease in the time the young population spends in physical activities is a consequence of the increase of the time spent in sedentary activities such as watching TV and using the computer (7) .The increase of the time spent in intellectual activities, such as school activities, language and computer courses, work (either paid or not), and the ease in waving physical education at school are factors that contribute to a sedentary behavior (8) .
The regular practice of physical activities during adolescence can promote physical growth, increase self-esteem, and contribute to the development of social skills.Literature evidence shows that the practice of physical activities during adolescence may be associated to the level of physical activities during adulthood (9) .
Since population-based studies with adolescents and adults in Northeastern Brazil are rare, this study aimed to estimate the prevalence of physical inactivity during leisuretime in young people from Feira de Santana, state of Bahia.We hope our results can foster the introduction of measures to promote and stimulate physical activities, which in its turn, as literature shows, can be an important element in the prevention of the major injuries and non-communicable chronic diseases of modernity.

method
An epidemiological cross-sectional study was performed in a representative sample of the urban population over 15 years old in Feira de Santana.The areas were selected through a stratified sample by subdistrict with random criteria, using census data from the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística, IBGE) (10) .
The analyzed data included 3,597 subjects of 15 years or older.However, for this study, the target population selected was of 1,400 young people from 15 to 29 years, according to the age classification of the National Youth Council (Conselho Nacional da Juventude) (11) for adolescents (from 15 to 17), youths (from 18 to 24), and young adults (from 25 to 29).
The following procedures were adopted to select the sample: percent representation of the population per urban area subdisctrict; definition of the percentage in each subdisctrict's sample, made from the resident population data from each subdisctrict; list of the census sectors in each subdistrict; random selection of census sections included in the sample; random selection of streets; selection of houses.
The houses in the selected streets were visited and inhabitants aged 15 years or more were considered eligible for this study.To reduce the loss percentage, up to three visits per house were made, excluding those that refused to participate in the study and the individuals that were not found in their houses after three visits.
The data were collected through an individual questionnaire that had sociodemographic info, info on self-reported diseases and life habits, such as alcohol drinking, smoking, leisure activities, physical activities and mental health practices.
To evaluate physical inactivity during leisure-time, subjects were asked if they regularly participated in physical activities during their leisure moments, of what kind were these activities, and how they classified their intensity: light, moderate, or heavy.
Subjects who classified their physical effort in leisure as moderate -at least two hours per week of activities such as walking, biking, dancing classes, -or heavy -at least four hours per week of activities such as jogging, gymnastics, swimming, ball games -were considered active in their leisure.Those who did not participate in physical activities or just described sedentary behaviors in their leisuretime (activities such as reading, listening to the radio, or watching TV) were considered inactive.The adopted procedure was similar to that used in other studies found in the literature (12)(13)(14)(15) .
The database was built and analyzed using the statistical program Statistical Package for Social Sciences (SPSS), version 9.0 for Windows.In the analysis, the global prevalence of physical inactivity of the studied population was estimated.The prevalence of inactivity according to sex and age were also evaluated.The chi-square test was calculated to analyze the association of the investigated variables, adopting a significance level of p<0.05.Info about some of the characteristics researched in this study were lost due to questionnaires filled incorrectly or absence of an answer by the respondent.
The study was submitted to and approved by the Human Being's Research Ethics Committee of Universidade Estadual de Feira de Santana, under the Opinion n. 042/2006.The adopted procedures followed the recommendations established by the Resolution n. 196/96 of the Brazilian National Health Council (Conselho Nacional de Saúde).

results
Of the selected population, 47.7% were aged 18 to 24 years; 68.4% were female; 68.5% were single; 81.8% were black (self-reported as brown or black); and 55.4% were finishing or still attending secondary education (Table 1).
Soccer/volleyball (23.2%) and walking (12.2%) were the physical activities most practiced during leisuretime (Table 2).Global physical inactivity in leisure was of 63.3%.Analyzing physical inactivity according to sex, physical inactivity in men was less prevalent than in women (Table 3).Physical inactivity in leisure changes with age: from the 15-17 to the 18-24 group the prevalence of physical inactivity increased.However, from 25 onwards a decrease occurred in the percentage of subjects classified as physically inactive in leisure (Table 4).The intensity of physical activity according to age group showed that only 7.7% of youths and 9.4% of young adults take part in leisure-time physical activities considered heavy, a percentage much smaller than the 17.7% of adolescents.The presented profile of leisure activity practices is characterized by the high prevalence of physical inactivity in leisure among young people.

Discussion
Regular physical activity is an important behavior in people's lives and presents a significant impact in the prevention and control of non-communicable chronic diseases, also helping the control of stress, anxiety and depressive symptoms.
The physical activities most practiced by young people during their free time were walking, soccer and volleyball, while hydrogymnastics was the least attended physical activity.Two categories may influence physical activities' patterns: individual characteristics, including motivations, self-efficacy, motor skills, and other health behaviors; and environmental characteristics, such as access to work or leisure spaces, costs, time availability barriers, and sociocultural support (16) .The prevalence of soccer and volleyball as the major preferences of adolescents and young adults has been indicated in several studies (17) and, as noted above, may be caused by cultural aspects, such as the extensive dissemination of soccer in Brazilian society, especially among men.These activities, besides, do not have a high cost, which can help their practice in our social contexts.
The frequency of physical inactivity among young people from Feira de Santana was high (72.8%).More than half of the respondents was considered inactive in leisure, that is, they reported they did not participate in physical activities or participated only in light physical activities during their free time.Lopes et al (13) , in a study performed with 2,022 adults from 20 to 59 years old from the city of Lages, state of Santa Catarina, Brazil, detected a smaller prevalence of physical inactivity (only 29.6%) than the one detected in this study.Burton e Turrel (15) described results close to the ones found in Feira de Santana, with a 67.7% prevalence of physical inactivity in adults living in Australia.Tenório et al (9) , detected that 65.1% of adolescents attending secondary education were insufficiently active.
Obtained results show physical inactivity is higher among women, confirming results from the literature (17) and showing the need for actions to promote physical activities among women.
During the classification of physical activity effort, it was found that a low percentage of subjects reported practicing high intensity physical activities.Besides, the intensity of physical activity was considerably reduced with age.
For Tenório et al (9) , participation in physical education classes is a factor associated both to the level of physical activities' practice and to the exposure to non-sedentary behavior in secondary school students.Schools must be attentive to the planning of this subject in the school environment, so that young people be encouraged to take part in physical activities.Since this is a phase in life in which group activities are very motivating, the organization of teams, championships and extra activities in school can be improved so that spaces of social exchange be enlarged, increasing the possibility of adolescents and youths participating in these activities.The benefits of these programs and actions can be even greater, since physical activity habits in adolescence are associated with physical activity during adulthood (17).
Other aspect that can be highlighted is that the probability of overweight is larger among sedentary young people, what increases exposure to cardiovascular diseases.In a research with adolescents, Silva et al (16)  inactive adults (≥18 years).Among the state capitals of the Northeast region, the city of Salvador, state of Bahia, presented the smaller percentage of people physically inactive in leisure (29%), while the city of Recife, state of Pernambuco, presented the larger percentage (32.8%) (18).Sedentariness is acknowledged as a risk factor for noncommunicable chronic diseases and presents a high prevalence in several countries (19) .Studies show that a large part of the population does not meet the current recommendations on the practice of physical activities.When evaluating only physical activities performed during leisure-time, investigators have been detecting an even higher prevalence of sedentariness (20)(21)(22) .The high number of young people physically inactive in leisure is, thus, worrying.Keeping this sedentary behavior throughout life may lead to health damages, especially those related to non-communicable chronic diseases, thus compromising these individual's life quality and overloading the city's Public Health system.
The design of this study can be pointed out among its possible limitations, since a cross-sectional study prevents us to secure implicit causal relations between the studied variables.The instrument used to analyze physical activity in leisure was not especially built to investigate physical activity, but to perform a population survey with the primary purpose of studying the mental health conditions of the city's urban area residents.This can be a relevant limitation to this study, since it hindered the development of more specific aspects of physical activity in the studied population.The analysis of physical activity in leisure was set after the data collection.There was no validation nor was the test-retest agreement of the questionnaire checked for this purpose.However, a pilot study was performed to evaluate and better adequate the questions of the instrument.It is worth noticing, however, that this is a population-based study with a randomly selected sample, involving a significant number of subjects, what allowed us to obtain estimates for the event of interest (physical inactivity in leisure), adopting sample procedures to minimize potential biases in selection.
Results allow us to conclude that the young people population from Feira de Santana, state of Bahia, presents a high prevalence of physical inactivity in leisure, which is further shortened in its physical effort intensity with age.In view of the fact that 55.4% of these young people were finishing or still attending secondary education, actions to promote physical activities and the adoption of an active lifestyle may be developed in the school environment, especially in Physical Education classes.The construction of leisure equipments in public spaces (courts, walk lanes, soccer fields, pools), connected to the development of public policies oriented towards changes in behavior and the promotion of the adoption of an active lifestyle may contribute to the increase of the population's level of physical activity.

table 1 -
Distribution of young people from 15 to 29, according to sociodemographic characteristics

table 2 -
Percentage of the major leisure physical activities reported by the studied population

table 4 -
claim that the probability of overweight is 74% larger in not very active boys than in active ones.Data from the Risk and Protection Factors for Chronic Disease Watch by Phone Interview System (Sistema de Vigilância de Fatores de Risco e Proteção Para Doenças Crônicas por Inquérito Telefônico, VIGITEL), in a 2006 survey that covered the 26 Brazilian state capitals and the Federal District, showed a high percentage of physically Percentage of (active and inactive) levels of physical activity in leisure and spent effort in leisure physical activities according to age group