Stress buffering effects of physical activity in adolescents: the moderating role of physical activity attitudes

Abstract

Background

Adolescents may experience stressful life events and associated physical and psychological symptoms of stress. Physical activity has a buffering effect on stress. However, whether physical activity attitudes modulate stress, and the relationship between physical activity attitudes, physical activity, and stress symptoms is unclear. The present study focuses on whether adolescent stress events predict stress symptoms, whether physical activity buffers stress, and whether this stress-buffering effect is enhanced when attitudes toward physical activity are positive.

Methods

A stratified and cluster sampling method was used to select 2420 junior high school students from nine provinces from each of the three economic zones (with high GDP level, medium GDP level, and low GPD level) of eastern, western, and central China and the Adolescent Self-Rating Life Events Checklist, the Calgary Symptoms of Stress Inventory, the Physical Activity Rating Scale, and the behavioral attitude dimension of the Physical Activity Attitude Scale were used to investigate adolescent stress events, stress symptoms, physical activity, and physical activity attitudes respectively. There are 1,190 boys and 1,230 girls from seventh to ninth grade 12–15 years old.

Results

Adolescents’ stress events and stress symptoms showed a significant positive correlation (r = 0.479, P < 0.01). The more stressful events adolescents have, the more pronounced stress symptoms become. The interaction term between the total amount of physical activity and stress events was not influential on stress symptoms (P = 0.461), and neither was the distinction between high and moderate physical activity levels (P_h = 0.248, P_m = 0.245). There was a moderating effect of physical activity attitudes on stress buffering for moderate physical activity levels (P < 0.01). The moderating effect was stronger when adolescents had positive attitudes toward physical activity.

Conclusions

Adolescent physical activity can buffer the effects of stress events on stress symptoms when physical activity attitudes are positive, revealing that stimulating adolescents’ physical activity initiative can promote physical activity to buffer stress.

Introduction

In recent years, mental health problems have gradually become a common social problem throughout the world and have shown a trend of “younger aging”. According to the Report on National Mental Health Development in China (2021–2022), adolescents are at the highest risk of depression, with a significant increase compared to the 2020 survey [1]. Poor interpersonal relationships, high parental expectations, and severe academic burdens, all of which may bring about psychological distress, mental exertion, and psychological burdens, expose adolescents to increasing psychosocial stress [2].

Stress is the process of dynamic adjustment between imbalance and equilibrium in individuals facing stressors that threaten their internal homeostasis [3]. A stress event is usually defined as a life experience that disrupts the homeostatic relationship between the individual and the environment, poses a threat to the individual’s physical and mental health, and may result from an environmental event or a disease suffered by the individual [4]. Stress symptoms are reactions to stressful events. Normally, the organism can adapt itself to stress. However, when the stimulus is more intense or persistent, it can cause some stress symptoms, for example, emotional problems such as anxiety and depression, as well as physical problems such as muscle tension, respiratory symptoms, and in severe cases, illness [5]. While physical activity is in fact a ‘physiological stressor’ placed on the body, when done properly, it has the benefit of buffering psychological stress. Physical activity can enhance the body’s immunity, improve the psychological state, and fight against psychological stress, which has the application value of buffering the psychological stress of adolescents [6]. Adolescents are in a period of rapid growth and development, and their mental health development is affected by many aspects such as school, family, and society, and the stress generated will have different degrees of impact on their physical and mental health [7].

Literature review

Physical activity can buffer the effects of stress. Physical activity can moderate the effects of academic stress in adolescents [8]. Likewise, physical activity can buffer the effects of family conflict on depression in junior high school students [9]. In addition, adolescents showed that physical activity levels can moderate the relationship between stressful life events and a healthy quality of life [10]. Physical activity has a potential stress-buffering effect on adolescents’ daily lives [11].

However, a stress-buffering effect of physical activity was not found after a randomized controlled study [12]. The buffering effect of physical activity in reducing the conversion of stress into stress symptoms was also unable to be validated [13]. Therefore, not all studies support a favorable stress-buffering effect of physical activity [14]. This may be due to the presence of moderating variables like physical activity attitude between physical activity and stress-buffering [15].

Physical activity attitude is closely related to physical activity behavior, and it can influence the intensity, frequency, and duration of individuals’ participation in physical activity. A positive physical activity attitude is a prerequisite for the formation of physical activity behaviors. Exercise attitude can be divided into three dimensions: cognitive evaluation, affective experience, and behavioral intention of physical exercise, and it can also be divided into eight dimensions of behavioral habitus, goal attitude, behavioral cognition, affective experience, subjective standards, behavioral control, behavioral attitude, and behavioral intention [16, 17]. Positive physical activity attitudes can increase the likelihood of developing physical activity behaviors [18]. The facilitating effect of physical activity attitudes on people’s engagement in physical activity may be because it can modulate people’s behavioral choices and behavioral responses to sports or participation in physical activity, and influence people’s learning and mastery of sports knowledge and the achievement of physical activity effects [19]. Physical activity attitudes are highly predictive of physical activity intentions [20].

Individuals with positive physical activity attitudes will also have higher cognitive evaluation, physical activity initiative, and affective experience of physical activity [21]. Especially in the context of school physical activity in China, adolescents are required to perform sports according to school requirements, but if adolescents are not highly motivated in sports, they may be passive in completing school-required sports and physical activity assignments, leading to a rebellious or coping mentality. Different dimensions of physical activity attitudes, for example, behavioral attitude, goal attitude, and affective experience are associated with the physical and psychological effects of physical activity. Thus, the stress-buffering effects of physical activity may be moderated by physical activity attitudes.

Besides, Fishbein and Ajzen developed The Theory of Multi-attribute Attitude and proposed The Theory of Reasoned Action [22]. The Theory of Reasoned Action is the predecessor of The Theory of Planned Behavior, which argues that behavioral attitudes determine behavioral intentions, and that expected behavioral outcomes and outcome assessment determine behavioral attitudes [23]. Since the Theory of Reasoned Action assumes that individual behavior is controlled by will, which seriously restricts the wide application of the theory, to expand the scope of application of the theory, Ajzen added perceptual behavioral control variables based on the Theory of Reasoned Action in 1985, initially proposing the Theory of Planned Behavior [24]. In 1991, Ajzen published the Theory of Planned Behavior [25]. The Theory provides a better understanding and prediction of an individual’s behavioral intentions and sense of self-efficacy and control and significantly improves the explanatory power of people’s specific attitudes toward behavior [26]. In general, the more positive an individual’s attitude towards a behavior, the stronger the individual’s behavioral intention; the more positive the subjective norms towards a behavior, the stronger the individual’s behavioral intention; and the more positive the attitude and subjective norms and the stronger the perceived behavioral control, the stronger the individual’s behavioral intention [27]. Thus, positive physical activity attitudes can increase the possibility of physical activity behaviors and may be able to moderate the stress-buffering effects of physical activity.

According to the fact that adolescents are facing an increasing number of stressful events. And stress symptoms are a response to stress events, for example, when the stimulus is more intense, it can lead to anxiety, depression, and even illness. However, physical activity can buffer the effects of stress. In addition, physical activity attitude is closely related to physical activity behavior and positive physical activity attitudes can increase the likelihood of developing physical activity behaviors. However, there is a lack of research on the relationship between physical activity attitudes, physical activity, stress events, and stress symptoms in adolescents. Therefore, based on the above literature review and theories, research hypothesis 1 was proposed: Adolescents’ stress events are positively related to stress symptoms. Hypothesis 2: Physical activity can moderate the positive relation between stress events and stress symptoms. Hypothesis 3: The moderating effect would be stronger if adolescents had positive attitudes toward physical activity. The hypothesis model is shown in Fig. 1.

Fig. 1

Hypothesis model diagram

Research methods

Sampling method and participants

First, the sampling sites were identified. In order to ensure the representativeness of participants, one city with high GDP level, one city with medium GDP level, and one city with low GPD level were selected from each of the three economic zones of eastern, western, and central China, according to the gross domestic product (East: Nantong, Jiangsu Province, Lishui, Zhejiang Province, and Fuxin, Liaoning Province; West: Chongqing, Yibin, Sichuan Province, and Ili, Xinjiang Uygur Autonomous Region; Central: Taiyuan, Shanxi Province, Puyang, Henan Province, and Xiangxi Tujia and Miao Autonomous Prefecture, Hunan Province). Second, one junior high school was selected in each of these nine cities, and using the stratified random cluster sampling method, local teachers were commissioned to distribute 100 paper questionnaires in each grade, for a total of 2,700 questionnaires. Complete the questionnaire by handwriting. Finally, 2,679 questionnaires were recovered, excluding 259 invalid questionnaires, obtaining 2,420 valid questionnaires, with an effective recovery rate of 89.6%. Informed consent was obtained from all participants and their parents included in the study. The basic information about participants is shown in Table 1.

Table 1 The basic information about participants

Measures

Stress events among adolescents

The Adolescent Self-Rating Life Events Checklist (ASLEC) revised by Xin et al. was used to assess adolescents’ recent stress events [28]. The scale is scored on a 6-point Likert scale. A score of “0” means “never happened” and “5” means “extremely impactful”. Higher scores indicate that the adolescent was more severely affected by the event. The scale consists of five dimensions with 26 questions, including 4 questions on the interpersonal stress dimension, 4 questions on the learning stress dimension, 7 questions on the punishment dimension, 6 questions on the loss dimension, and 5 questions on the adaptation dimension. The scale has items such as “Being misunderstood or misjudged”, “Suffering discrimination and neglect” and so on. In this study, the overall internal consistency coefficient of the scale, Cronbach’s α = 0.775, and the internal consistency coefficients of the dimensions ranged from 0.711 to 0.854. The results of the confirmatory analysis were as follows: X²/df = 4.759 < 5, NFI = 0.950 > 0.9, IFI = 0.952 > 0.9, TLI = 0.904 > 0.9, CFI = 0.952 > 0.9, and RMSEA = 0.033 < 0.08, indicating good construct validity.

Stress symptoms among adolescents

The Calgary Symptoms of Stress Inventory (C-SOSI) developed by Carlson and Thomas was used [29]. Two psychology graduate students were invited to translate the questionnaire, then one international student whose native language is English was invited to translate the Chinese questionnaire back, and then two psychology professors were invited to proofread and revise the Chinese and English questionnaires to form the Chinese version of the Stress Symptoms Inventory. The questionnaire contains 8 dimensions and 56 questions. Among them, there were 8 questions on the depression symptom dimension, 7 questions on the anger symptom dimension, 9 questions on the sympathetic arousal dimension, 6 questions on the neurological symptom dimension, 8 questions on the muscle tension symptom dimension, 6 questions on the cardiopulmonary arousal symptom dimension, 6 questions on the cognitive disorganization symptom dimension, and 6 questions on the upper respiratory symptom dimension. The scale has items such as “Unhappy and depressed”, “Alone and sad” and so on. A 5-point Likert scale was used for scoring. “0” means “never” and “4” means “very often”. The higher the score, the more pronounced the symptoms of stress. In this study, the internal consistency coefficient of the questionnaire was 0.941, and the internal consistency coefficients of each dimension ranged from 0.711 to 0.873, respectively.

Physical activity for adolescents

The Physical Activity Rating Scale (Liang, 1994) was used to measure the physical activity level of adolescents [30]. The scale consists of three items, i.e., weekly frequency of physical activity, duration of each physical activity, and usual intensity of physical activity. The total physical activity score is the product of the three. The answers to each item are divided into 5 levels, ranging from 1 to 5 for frequency and intensity, and 0–4 for duration, with the total score ranging from 0 to 100. Higher values indicate higher levels of physical activity among adolescents. A score of 0–19 is considered a low physical activity level, 20–42 is considered a moderate physical activity level, and a score of 43–100 is considered a high physical activity level. In addition, physical activity in this study included physical activity performed by participants both in and out of school. In-school physical activity currently consists of physical education classes and recess workouts, on average, 3–5 times a week, with 40 min per session for physical education classes and 35 min per session for recess workouts. As measured by the Physical Activity Rating Scale, each participant meets at least a moderate level of physical activity per week (2*4*4 = 32), so low levels of physical activity are not included in this study. The scale has high reliability and validity, with a retest reliability of r = 0.82 and an internal consistency reliability Cronbach alpha coefficient of 0.907.

Adolescent attitudes toward physical activity

The behavioral attitude dimension of the Physical Activity Attitude Scale developed by Mao was chosen to measure the level of adolescents’ attitudes towards physical activity [31].The scale consists of 8 items and is based on a 5-point Likert scale, ranging from “1” for complete compliance to “5” for complete non-compliance. The scale has items such as “I’m not in favor of spending time on physical activity.”, “I think I’m fine without physical activity.” and so on. The maximum score is 40 and the minimum score is 8. Higher total scores indicate higher levels of participants’ attitudes toward physical activity. The Cronbach’s alpha coefficient for this scale in this study was 0.79.

Data analysis

SPSS 25.0 and AMOS 24.0 were used for statistical analysis of relevant data. Confirmatory factor analysis of survey tools was completed using AMOS 24.0. Data were standardized using SPSS 25.0. The hypothesis model was tested using the common method bias test, descriptive statistical analysis, Pearson correlation analysis, and Bootstrap moderation effects analysis. Simple slope test with P < 0.05 as the criterion for statistical significance.

Results

Participants’ characteristics

The descriptive statistics of the participants’ total amount of physical activity, high physical activity level, moderate physical activity level, stress symptoms, stress events, and physical activity attitudes are shown in Table 2.

Table 2 Participants’ characteristics

Correlation analysis of variables

Correlation analyses of the study variables (see Table 3) showed that adolescents’ stress events and stress symptoms showed a significant positive correlation (r = 0.479, P < 0.01). The total amount of physical activity, stress events (r = -0.040, P < 0.05), and stress symptoms (r = -0.075, P < 0.05) were in low correlation. Physical activity attitudes showed a low correlation with stress events (r = -0.049, P < 0.05) and stress symptoms (r = -0.040, P < 0.05). Table 4 shows the high physical activity level and stress events (r = -0.014, P < 0.05) and stress symptoms (r = -0.034, P < 0.05) were in low correlation. Physical activity attitudes showed a significant negative correlation with stress events (r = -0.144, P < 0.01) and stress symptoms (r = -0.115, P < 0.05). Table 5 indicates that the moderate physical activity level showed a low correlation with stress events (r = -0.063, P < 0.05) and stress symptoms (r = -0.072, P < 0.05). Physical activity attitudes showed a low correlation with stress events (r = -0.025, P < 0.05) and stress symptoms (r = -0.072, P < 0.05).

Table 3 Correlation analysis of the total amount of physical activity and each variable

Table 4 Correlation analysis of the high physical activity level and each variable

Table 5 Correlation analysis of the moderate physical activity level and each variable

The moderating effect of physical activity and physical activity attitudes on stress

The buffering effect of physical activity on stress

Using model 3 in Process, with attitude towards physical activity, the total amount of physical activity, high physical activity level, and moderate physical activity level as moderating variables, stress events as independent variables, and stress symptoms as dependent variables. The results showed that the interaction term between the total amount of physical activity and stress events was not influential on stress symptoms (P = 0.46). Also, the interaction between the two did not have a significant impact on stress symptoms when distinguishing between high and moderate levels of physical activity (P_h = 0.25, P_m = 0.25), proving that physical activity does not act as a moderator against stress symptoms (see Table 6).

The moderating role of physical activity attitudes on the stress-buffering effect of physical activity

The interaction terms of adolescents’ physical activity attitudes with the amount of adolescent physical activity and adolescent stress events did not have a moderating effect on stress symptoms even when differentiating between the amount of physical activity. The interaction of physical activity attitudes, stress events, and physical activity also did not have a moderating effect on stress symptoms. However, if distinguishing the amount of physical activity, there was a moderating effect of physical activity attitudes on stress buffering for moderate physical activity levels (P < 0.05), while it was not significant for high physical activity levels (see Table 6).

Table 6 The moderating effect of physical activity and physical activity attitudes on stress symptoms

A simple slope test was conducted to further analyze how physical activity attitudes moderated the buffering effect of moderate physical activity on stress (see Fig. 2). The results showed that when adolescents possessed only low levels of moderate physical activity (M-1SD), there was no moderating effect regardless of the level of physical activity attitude. However, when adolescents had high levels of moderate physical activity (M + 1SD), high levels of physical activity attitudes moderated the buffering effect of moderate physical activity.

Fig. 2

Simple slope analysis of physical activity attitudes on the stress-buffering of moderate physical activity level

Discussion

A nationwide sample survey of adolescents’ physical activity, physical activity attitudes, stress events, and stress symptoms confirmed that positive physical activity attitudes have a stress-buffering effect of moderate levels of physical activity in adolescents.

The stress-buffering effect of physical activity in adolescents

The investigation showed that stress events in adolescents can positively relate to stress symptoms, confirming Hypothesis 1. The results showed that the interaction between physical activity and stress events was not significant in stress symptoms, and neither was the distinction between high and moderate physical activity levels. This is inconsistent with the findings of Chen et al. and Sallis et al. on the impact of physical activity on health in secondary school students [32, 33] and the stress-buffering hypothesis of physical activity [34, 35]. The stress-buffering effect of physical activity is considered a potentially effective means of preventing stress-related symptoms, and diseases [36]. The cross-stressor adaptation hypothesis provides a possible biological explanation for the stress-buffering effects of physical activity [37]. Physical activity elicits non-specific adaptations in the ‌Autonomic Nervous System and Hypothalamic-Pituitary-Adrenal Axis of the autonomic nervous system, causing habituation of the physiological stressor system and possibly leading to reduced sensitivity to subsequent homotypic (physical) and heterotypic (psychosocial) stressors [38]. However, the result is consistent with the results of another research study on adolescents where no significant moderating effect of physical exercise on the relationship between stress and life satisfaction was found [39]. The reasons that physical activity does not act as a buffer against stress may be that the amount of physical activity of students tends to decline during adolescence, negative motivation to engage in physical activity due to a negative lifestyle resulting from increased academic pressure, and so on. Besides, this study only explored the buffering of stress symptoms by physical activity. In contrast, studies supporting the stress-buffering effect of physical activity in adolescents have investigated other variables such as negative emotions, e.g., depression and complaining, or positive emotions, e.g., happiness [40]. Thus, physical activity may have a smaller effect on stress symptoms than mood. This result suggests that adolescent physical activity may not adequately buffer the worsening of stress symptoms due to increased stress events. Another reason may be that there are amplifying or attenuating moderators that influence the buffering effect of physical activity on the relationship between stress events and stress symptoms. If these moderators are not placed in the relationship model, then this may result in a non-significant stress-buffering effect. This analysis suggests that our hypothesized physical activity attitudes may moderate the buffering effect of physical activity on stress.

Moderation of the stress-buffering effect of physical activity attitudes on physical activity in adolescents

The results showed that the stress-buffering effect was moderated only when adolescents possessed high levels of moderate physical activity and positive physical activity attitudes. Thus, physical activity attitude is an important factor that requires special attention. The development and motivation of physical activity attitudes should be advocated when attempting to buffer stress through physical activity. Exercise attitude could effectively predict exercise behavior [41]. Kaj et al. investigated the physical activity attitude of 961 adolescents and found that there was a positive correlation between physical activity attitude and physical activity [42]. The theory of planning suggests that physical activity attitudes have an influence on physical activity behavior, and existing studies related to the theory of planned behavior have consistently demonstrated this relationship [43]. Therefore, physical activity attitudes would be a key variable in promoting physical activity among adolescents.

The stress-buffering effect of physical activity is stronger when the level of physical activity attitude is higher. Adolescents’ active and positive physical activity helps to achieve better physical activity effects, on the contrary, if adolescents’ physical activity attitudes are negative, then even if the school arranges enough physical activity or out-of-school physical education assignments, then adolescents can hardly get the expected effects. Therefore, when individuals recognize the important role of physical activity and want to take the initiative to engage in it, it will help physical activity buffer against stress. Psychological Reactance Theory suggests that when an individual is unwilling to engage in a behavior, psychological resistance may arise and motivate the individual to act in opposition to the passive behavior. Psychological resistance may lead to negative attitudes toward the source of the threat (e.g., resentment), as well as negative emotions such as anxiety and depression [44]. If adolescents’ physical activity attitudes are negative, increased physical activity in schools may elicit negative emotions, thereby reducing the buffering effect of physical activity on stress. The results of this study not only emphasize the importance of physical activity attitudes but also qualify them specifically for the adolescent period. Adolescents are prone to rebelliousness and improving adolescent attitudes toward physical activity so that adolescents are motivated to be physically active increases the likelihood that they will benefit from physical activity in a way that buffers them from stress.

If a separate distinction is made between physical activity at high and moderate levels, then physical activity attitudes have a significant moderating effect on stress buffering for moderate physical activity levels, but not for high physical activity levels. Meta-analytic evidence on physical activity for depression has been presented to support this notion, with moderate-intensity physical activity alleviating depression, whereas sustained heavy physical activity may act as a stressor, thereby exacerbating an individual’s depressive symptoms [45]. The effects of physical activity on psychological stress showed that Prolonged strenuous physical activity (VO2 max ≥ 60–70%) not only fails to alleviate psychological stress but also induces typical stress symptoms [46]. High physical activity level leads to increased concentrations of cortisol, adrenaline, and noradrenaline, and reduced blood flow in organs such as the viscera to redistribute oxygen to working muscles. Subsequently, reduced blood supply to the intestinal epithelium and reperfusion will lead to hypoxia, acidosis, adenosine triphosphate depletion, free radical formation, and oxidative or nitrosative stress, which will combine to disrupt the intestinal barrier and lead to increased intestinal permeability. Next, lipopolysaccharide or endotoxin translocation into the circulatory system leads to inadequate intestinal blood, nutrients, water, and oxygen supply, inducing typical stress symptoms such as inflammatory response and gastrointestinal distress. However, there is also the cross-stressor adaptation hypothesis that suggests that high-intensity, competitive, and confrontational physical activity is an effective stimulus for fostering the organism’s adaptation to psychological stress [47]. However, adolescents may have conditions such as high levels of learning stress and therefore may not be suitable for additional stressor stimulation to foster organismic coping. For moderate physical activity level is more suitable as an intervention for adolescents with certain stress levels. Long-term, regular, small to medium-intensity exercise such as yoga is more suitable for relieving individuals with high stress levels [48]. Physical activity at moderate levels is an effective method of relieving psychological stress in adolescents [49]. Therefore, moderate levels of physical activity with positive physical activity attitudes are recommended for adolescents for stress buffering.

Limitations and strengths

This study has the following limitations. First, the reduction in the amount of physical activity among adolescents due to increased academic stress may affect the buffering effect of physical activity on stress. China’s high school enrolment rate has dropped dramatically, leading to intense competition for higher education, which has led to junior high school students spending more time on in-school and out-of-school learning than on physical activity. The influence of this aspect on the findings should be considered. Second, this study only explored the buffering effect of physical activity on stress symptoms with the moderating role of physical activity attitudes. Some other variables were not considered, such as negative emotions, positive emotions, and so on. For instance, negative emotions can hinder the extent to which an individual can accomplish things, while positive emotions can promote someone’s behavior toward accomplishing something. So, more variables could be included in subsequent studies for research. Third, the study measured adolescents’ physical activity, physical activity attitudes, stress events, and stress symptoms through the total scores of the scales and did not analyze the subscales. The scale used to measure stress events contains five dimensions, interpersonal, learning, punishment, loss, and adaptation, and the scale to measure stress symptoms, contains eight dimensions, depression, anger, sympathetic arousal, neurological symptom, muscle tension symptom, cardiopulmonary arousal symptom, cognitive disorganization symptom, and upper respiratory symptom. The use of these subscales would provide a more detailed analysis to clarify the relations between variables. Thus, a more comprehensive analysis of adolescent stress events and stress symptoms can be conducted in conjunction with the subscales in more in-depth studies in the future. In addition, this study has the following strengths. First, the sample size is large and covers nine provinces from each of the three economic zones (with high GDP level, medium GDP level, and low GPD level) of eastern, western, and central China, so the sample is representative to some degree. Second, this study explores the relationship between physical activity attitudes, physical activity, stress events, and stress symptoms in relative depth, and shows that positive physical activity attitudes have a stress-buffering effect of moderate levels of physical activity in adolescents which not only emphasizes the importance of physical activity attitudes but also qualify them specifically for the adolescent period when they are prone to rebellion. By improving adolescents’ attitudes towards physical activity, adolescents will be motivated to participate in physical activity, increasing the likelihood that they will benefit from physical activity, and to some extent buffering their stress.

Conclusion

This study focuses on the buffering effect of adolescent physical activity on stress with the moderating role of physical activity attitudes. A nationwide sample was adopted, and the study suggests that the stress-buffering effect works when adolescents have positive attitudes toward physical activity and induce high levels of moderate physical activity. Therefore, physical activity programs for adolescents to alleviate stress are recommended to some extent to promote physical activity. However, the intensity and duration of physical activity need to be controlled. Besides, we should pay attention to moderate levels of physical activity. At the same time, it is beneficial to promote the positive effects of physical activity on adolescents and to foster their positive attitudes toward physical activity.