Relationships among Physical Self-Concept, Physical Activity and Mediterranean Diet in Adolescents from the Province of Granada

Children 2021, 8, 901. https://doi.org/10.3390/children8100901 www.mdpi.com/journal/children Article Relationships among Physical Self-Concept, Physical Activity and Mediterranean Diet in Adolescents from the Province of Granada Mariana Pérez-Mármol 1 , Ramón Chacón-Cuberos 1, *, Eduardo García-Mármol 2 and Manuel Castro-Sánchez 3 1 Department of Research Methods and Diagnosis in Education, University of Granada, 18071 Granada, Spain; [email protected] 2 Department of Physical Education and Sports, University of Granada, 18071 Granada, Spain; [email protected] 3 Department of Didactics of Musical, Plastic and Corporal Expression, University of Granada, 18071 Granada, Spain; [email protected] * Correspondence: [email protected] Abstract: The aim of the present research was to analyse the relationships among physical self-concept, physical activity engagement and Mediterranean diet adherence in a sample of 1650 secondary school students from the province of Granada. The study design was descriptive–exploratory, crosssectional and ex post facto. Measurements were taken from a single group. The PSQ, PAQ-A and KIDMED questionnaires were used to measure diet quality. Results showed the presence of a positive relationship among all dimensions of physical self-concept and physical activity engagement, with better outcomes being achieved in this self-perception with increasing engagement in sport. With regard to diet quality and its repercussions on physical self-concept, it was highlighted that the dimensions of the general self-concept, physical attractiveness and strength tended to be more positive as quality improved. In contrast, worse outcomes were produced in those with a low-quality diet. In this way, it was deemed necessary to continue investigating psychosocial factors with the aim of clarifying the relationships with psychological factors and health indicators. This would enable the development of prevention and intervention programs focused on promoting wellbeing in adolescents. Keywords: psychosocial wellbeing; physical activity; diet quality 1. Introduction Adolescence is an a priori term that is complex to define due to the variety of biological and sociocultural factors that intervene at the time of establishing consensus in relation to its chronology. Nonetheless, generally speaking, it defines the transitional stage located between infancy and adulthood covering, approximately, the ages of 10 y to 20 y [1]. This period is considered key in the lifecycle of human beings, given that it is during this period that the foundations of identity and personality are constructed, whilst numerous changes also take place at a physical, sexual, emotional, social and moral level. These changes later give rise to the development of variations in attitudes, thoughts, behaviours, concerns and interests, which will mark, in a decisive way, the future of adolescents [2,3]. In the search for quality of life, wellbeing and optimal development, the basic health of young people is an essential requirement. For this reason, adolescence is proposed as an excellent opportunity to promote the acquisition of healthy habits that will last throughout life [4–6]. Self-concept is one of the most important psychosocial factors involved in the construction and development of the “self”. This is defined as the set of opinions, hypotheses Citation: Pérez-Mármol, M.; Chacón-Cuberos, R.; García-Mármol, E.; Castro-Sánchez, M. Relationships among Physical Self-Concept, Physical Activity and Mediterranean Diet in Adolescents from the Province of Granada. Children 2021, 8, 901. https://doi.org/10.3390/ children8100901 Academic Editor: Tonia Vassilakou Received: 22 July 2021 Accepted: 8 October 2021 Published: 9 October 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses /by/4.0/). Children 2021, 8, 901 2 of 15 and ideas that an individual has about themselves [7]. At present, self-concept is not seen from a unidimensional or hierarchical perspective, but rather, from a multidimensional, dynamic and acquired character, which may or may not improve depending on each experience or moment. According to the model conceived of by [8,9], this construct is composed of five dimensions: social, emotional, family, academic and physical. This research focuses on the study of the last dimension mentioned, being a domain of self-concept with which it establishes high and consistent relationships [10,11]. This variable was selected because, as highlighted by numerous previous studies, a relationship exists between physical self-concept and various aspects of general health, such as physical activity engagement and correct nutrition [12–18], the body mass index and obesity [19–21]. A relationship has also been shown among social pressure, the means of communication and body dissatisfaction [22–28]. Specifically, physical self-concept refers to the cognitive description constructed by an individual, as a function of the following four subdomains: sport ability, physical strength, physical attractiveness and physical condition. Factors considered to influence perceptions of the aforementioned aspects concern the setting and past experiences [26,29,30]. A combination of physical activity and a balanced diet has been shown to have the best health benefits. This “holy union” can contribute to reducing the likelihood of suffering chronic conditions during adult age [31,32], perceiving greater life satisfaction and mental wellbeing [14,16,22,24,31–35], improving academic performance [36–38] and favouring variables related to the quality of life [4,15,39,40]. The need to combat physical inactivity and sedentary lifestyles has been urged at a global level in recent years. Concretely, during the current stage of the COVID-19 pandemic, being physically active and following healthy habits take on huge importance in both homes and educational institutions [41–45]. The infant population has reached alarming levels of a sedentary lifestyle, pointing to an increased risk of maintaining the same weight predisposition into adolescence and adulthood [46–48]. Given the prevalence of overweight, research in national and international contexts has been refined. It is now defined as a complex and multifaceted disease with diverse origins. Given that the influence of genetic, environmental, social and/or economic factors takes a leading role, the design of effective policy is difficult [49–53]. It is also notable that a relationship has been highlighted between greater body mass and a more negative physical self-concept, showing that this index is also associated with a worse image of one’s self. This reality is accentuated in adolescence given that the lack of maturity and critical thinking, together with the impact of social networks and mass media, can cause the construction of a personal identity based on beauty ideals set by society. This can pose risks to the physical and mental health of adolescents, in addition to eating disorders [54–58]. One of the conditioning factors behind the aforementioned incidence of overweight and high body dissatisfaction are the changing nutritional patterns that have been seen in recent years and that occur from early ages, leading to increases in the consumption of unhealthy diets (fast food). The Mediterranean diet has been confirmed to constitute one of the dietary models that is most beneficial to health due to the protective effects it exerts [59–61]. According to Serra [62], the Mediterranean diet is characterised by the consumption of vegetables, fruits, legumes, fish, nuts and olive oil, in addition to being low in saturated fats and rich in antioxidants. Alfonso [63] denominated this diet as the combination of foods produced by local agriculture, according to local recipes and traditional cooking methods characteristic of each geographical region. However, it also includes regular engagement in physical activity, alongside a healthy and respectful approach to the environment [64]. Another conditioning factor is the exponential increase in physical inactivity. This is issue has become so big that the WHO [65] has denominated it a general challenge to public health. Authors such as Macek et al. [66] have established minimum physical activity guidelines for children aged between 6 y and 17 y. These guidelines are as follows: Children 2021, 8, 901 3 of 15 engage in moderate-to-vigorous aerobic physical activity for more than 60 min a day; engage in vigorous aerobic physical activity at the least three times a week; engage in muscle strengthening activity at least three times a week. Likewise, Llamazares [67] indicated the main reasons for engaging in physical activity at these ages. These motives include benefits in the educational setting, healthier habits in general, the promotion of social relationships and the obtainment of pleasure and enjoyment. In this way, given the numerous research studies that have concisely related the aforementioned variables, the main objective of the present study was to determine the relationships between physical self-concept, physical activity engagement and Mediterranean diet adherence in a sample of adolescents undertaking secondary school education. Based on this objective, the following three hypotheses were proposed: • Physical activity will be positively related to physical self-concept; • Adolescents reporting poorer diet quality will have a lower physical self-concept; • Physical self-concept will be strongly influenced by its dimensions, the practice of physical activity and the quality of the diet. 2. Materials and Methods 2.1. Subjects and Design The present study was nonexperimental, quantitative, descriptive–exploratory, cross-sectional and ex post facto in nature. Measurements were taken from a single group. The study population of the present sample constituted all secondary school students enrolled at state-funded institutions in the province of Granada during the 2019/2020 academic year. According to the Statistical and Cartographic Unit housed within the Ministry of Education and Sport of the Local Government of Andalusia (Spain) (2020), students enrolled in the aforementioned general course of education in the province of Granada totalled 53,198 overall. In line with the criteria established by Otzen [68], all adolescents who agreed to participate and met certain inclusion criteria were considered as part of the study population. Inclusion criteria were as follows: (a) be enrolled in state-funded secondary education during the 2019/2020 academic year; (b) be aged between 11 y and 20 y; (c) provide signed informed consent for the handling of data pertaining to minors, where relevant. Likewise, exclusion criteria were established with the aim of obtaining a reliable sample. These were as follows: (a) suffering from any type of pathology or condition that would impede the correct completion of the questionnaire; (b) returning incomplete questionnaires or responses that could create confusion (responses crossed or rubbed out). Finally, a final sample of 1650 students was obtained (Figure 1). Participants were aged between 11 y and 20 y (M = 14.48; SD = 1.41), with 50.4% (n = 832) being boys and 49.6% (n = 818) being girls. Finally, with regard to the degree of representativeness of the sample, a final sampling error of 0.023 was obtained or, in other words, a 2.37% margin of error assuming a 95% confidence level. Children 2021, 8, 901 4 of 15 Figure 1. Sample distribution. 2.2. Instruments The present study employed the following instruments: the KIDMED questionnaire. This instrument was developed by Serra [69] based on a previous study conducted with children and adolescents, denominated EnKid. Following this, the KIDMED questionnaire was conceived of, comprising 16 questions designed to evaluate the adherence of respondents to a Mediterranean diet. Responses were recorded as positive (the respondent’s diet meets dietary behaviour guidelines and corresponds to a Mediterranean diet) or negative evaluations (the respondent does not adhere to this diet). Specifically, the test was divided into four questions that had negative connotations (−1), whilst the twelve remaining questions were evaluated with a positive score (+1). The outcome was interpreted according to the following classification: (a) from 8 to 12: optimal adherence, in other words the respondent consumes a Mediterranean diet to a large extent (high); (b) from 4 to 7: moderate adherence; the respondent is required to improve his/her dietary pattern in order to adopt the Mediterranean model (medium); (c) from 0 to 3: very lowquality diet and, therefore, very low level of adherence to the Mediterranean diet (low). The reliability of the original instrument was determined as α = 0.854, and the present study obtained a lower index of α = 0.523. It should be noted that this coefficient is relatively low, which could be due to the reduced number of items and the confusion generated by the items formulated in the negative sense. PAQ-A questionnaire: This questionnaire was developed by Martínez [70] and is composed of 9 questions, which evaluate the physical activity performed by the adolescent during the seven days prior to administration. The considered physical activities include that performed during free time, physical education classes, extracurricular classes and activity engaged in at the weekend. Questions 1 to 6 provide information about the types of sport. Questions 7 and 8 indicate physical activity intensity, alongside the frequency with which it is performed. Finally, Question 9 provides additional specific information pertaining to whether or not regular engagement in physical activity was impeded for some reason. Responses were recorded along a 5-point Likert scale. The internal consistency of this scale was α = 0.77 in the original study, with the present research obtaining a higher index of α = 0.861. The scores of this scale were worked out in two ways: (a) Children 2021, 8, 901 5 of 15 summation or total score of the scale; (b) division of the total score into tertiles: low level of PA (scores included in the first tertile of the total score), medium level of PA (scores included in the second tertile of the total score) and high level of PA (scores included in the third tertile of the total score). Specifically, it was observed that 34.2% (n = 570) of the sample were located at the low level, 50.7% (n = 844) at the medium level and only 14.2% (n = 236) associated with a high PA level. Physical Self-concept Questionnaire (PSQ) validated by Goñi [71]: This was originally validated by these authors given the need to generate a reduced scale based exclusively on physical self-concept, in order to solve the limitations of the “Self Description Questionnaires (SQD)” based on the Marsh [72] model and the versions of the multidimensional self-concept of García [8]. The PSQ is a questionnaire composed of 36 items, distributed between two general scales (general physical self-concept and general self-concept) and four scales, which evaluate the four dimensions of physical self-concept (physical ability, physical condition, physical attractiveness and strength). With regard to reliability, this questionnaire achieved an excellent index of α = 0.927, with a highly similar index of α = 0.93 being obtained in a study conducted by Goñi [71]. Likewise, acceptable reliability indices were obtained for each dimension separately: GS, general self-concept (α = 0.722); SF-G, general physical self-concept (α = 0.802); SF-PA, physical ability (α = 0.754); SF-PC, physical condition (α = 0.831); SF-PAT, physical attractiveness (α = 0.803); SF-PS, physical strength (α = 0.751). 2.3. Procedure Firstly, researchers from the Department of Research and Diagnostic Methods in Education, together with the Department of Musical, Artistic and Bodily Expression, put together and sent off the pertinent permissions. This was made up of informed consent forms and approval for data collection from minors. Forms were prepared for both educational institutions and families (or legal guardians). An information letter was prepared, which described the nature of the study and its aims, in addition to the research instruments that would be used and the way in which the data would be handled and used (only for scientific purposes). This serves to highlight that the present study adhered to the principles of the Declaration of Helsinki (updated in 2008) and that participants’ rights to confidentiality were respected at all times (Law 15/1999 of 13 December). Likewise, the research was supervised by the Research Ethics Committee of the University of Granada (Reference Number 2150/CEIH/2021), on 4 May 2021. Once approval was received from educational institutions and legal guardians, data collection proceeded. Data were collected manually and in-person at the institutions, during hours agreed by the faculty and management. It should be indicated that, overall, 7 state-funded institutions from the province of Granada participated, and these data were gathered between January and March of the 2019/2020 academic year. Following the conclusion of the data collection period, data handling and analysis proceeded. As the first step, all incomplete questionnaires were discarded, along with those that presented confusing or unreliable responses. Once this task was completed, the data were cleaned in the database and introduced into the software IBM SPSS® 22.0 (IBM Corp, Armonk, NY, USA) in order to create the data matrix. This process of review and transcription was performed throughout by the principal investigator with the aim of ensuring correct data handling, whilst at the same time avoiding mistakes due to data omission or incorrect assignment. 2.4. Data Analysis Data analysis was conducted using the statistical package IBM SPSS® 22.0 (IBM Corp, Armonk, NY, USA). Specifically, frequencies, means, standard deviations and percentages were used for the analysis of the basic descriptive data. On the other hand, associative analyses employed one-way ANOVA, the Bonferroni test for between-group associations and bivariate Pearson correlations. In order to examine the significance of associations between variables, the Pearson chi-squared test (0.05 *; 0.01 **; 0.000 ***) and Welch Children 2021, 8, 901 6 of 15 test were employed. Data normality was evaluated according to the values of kurtosis, with values lower than 2 being required. Homoscedasticity was examined using the Levene test. Finally, a univariate linear model was used to determine the influence of all variables on the general physical self-concept. This serves to highlight that the internal reliability of the instruments used was evaluated through Cronbach’s alpha, establishing a 95.5% reliability index. 3. Results Table 1 shows the basic descriptive data of the variables under study. Specifically, it was observed that 50.4% (n = 832) of the subjects were men, while 49.6% (n = 818) were women. In relation to the tertiles established for physical activity, 34.5% (n = 570) showed a low level, while 51.2% (n = 844) had a medium level and 14.3% (n = 236) a high level. Diet categorization revealed that 23.3% (n = 385) had a low-quality diet, 49.8% (n = 821) of medium quality and 26.9% (n = 444) of high quality. Finally, the mean values of self-concept and its dimensions are shown, observing from the highest to lowest score: SF-G (22.25 ± 5.88), SF-PAT (21.34 ± 5.77), SF-PA (20.82 ± 5.20), SF-PC (20.35 ± 5.68) and SF-PS (19.21 ± 5.23). The general self-concept obtained a value of 23.28 ± 4.96. Table 1. Descriptive data of the sample. Frequency (n) Percentage (%) Gender Men 832 50.4 Women 818 49.6 Tertiles of physical activity Low 570 34.5 Medium 844 51.2 High 236 14.3 Tertiles of diet quality Low 385 23.3 Medium 821 49.8 High 444 26.9 Mean Score Standard Deviation (SD) Self-concept SF-PA 20.82 5.20 SF-PC 20.35 5.68 SF-PAT 21.34 5.77 SF-PS 19.21 5.23 SF-G 22.25 5.88 GS 23.28 4.96 Note: GS, general self-concept; SF-G, general physical self-concept; SF-PA, physical ability; SF-PC, physical condition; SF-PAT, physical attractiveness; SF-PS, physical strength. Table 2 presents scores for physical self-concept and its dimensions according to physical activity level. In both cases, a growing and positive trend is seen with increasing sport engagement. Concretely, data obtained for the dimension describing general selfconcept were higher when young people practiced more physical activity. The same pattern was seen with the dimensions pertaining to the general physical self-concept, physical ability, physical condition, physical attractiveness and strength. In fact, Table 1 shows higher mean values for each dimension of physical self-concept for the “high” category, followed by the medium and low levels. Children 2021, 8, 901 7 of 15 Table 2. The levels of physical self-concept according to the levels of physical activity. PA Level M SD 95% CI Homogeneity of Variance ANOVA Welch Test LL UL Lev. Sig. F Sig. W Sig. GS Low 22.29 a,b,c 5.09 21.87 22.71 1.06 0.344 19.96 0.000 - - Medium 23.65 a,b 4.82 23.32 23.97 High 24.38 a,c 4.78 23.77 24.99 SF-G Low 20.48 a,b,c 6.10 19.98 20.98 4.21 0.015 46.06 0.000 43.16 0.000 Medium 22.91 a,b,c 5.47 22.53 23.28 High 24.19 a,b,c 5.72 23.46 24.92 SF-PA Low 17.69 a,b,c 4.91 17.29 18.10 1.90 0.149 222.60 0.000 - - Medium 21.96 a,b,c 4.52 21.65 22.26 High 24.30 a,b,c 4.22 23.75 24.84 SF-PC Low 16.89 a,b,c 5.09 16.47 17.31 1.80 0.165 251.07 0.000 - - Medium 21.45 a,b,c 5.03 21.11 21.79 High 24.77 a,b,c 4.46 24.19 25.34 SF-PAT Low 19.80 a,b,c 6.14 19.29 20.30 9.39 0.000 41.14 0.000 40.93 0.000 Medium 21.78 a,b,c 5.41 21.41 22.15 High 23.49 a,b,c 5.10 22.84 24.15 SF-PS Low 16.82 a,b,c 4.85 16.42 17.22 0.11 0.891 139.65 0.000 - - Medium 19.83 a,b,c 4.87 19.50 20.16 High 22.77 a,b,c 4.68 22.17 23.37 Note 1: GS, general self-concept; SF-G, general physical self-concept; SF-PA, physical ability; SF-PC, physical condition; SF-PAT, physical attractiveness; SF-PS, physical strength. Note 2: a, b, c, Post hoc (Bonferroni)—pairwise between-group comparisons. Note 2: PA, Physical Activity; M, Mean; SD, Standard Deviation; CI, Confidence Intervals; LL, Lower Limit; UL, Upper Limit; Lev., Levene-test; Sig., Level of significance; F, F-test; W, Welch statistic. Table 3 presents the different dimensions of physical self-concept according to diet quality. With regard to the dimension of the general self-concept, a positive trend is seen with increasing Mediterranean diet adherence, in addition to with physical attractiveness and strength. With regard to the general physical self-concept, in contrast, data revealed better outcomes in those with a poor-quality diet. The same occurred with the dimension describing physical ability, in which a negative trend was observed with a poorer-quality diet leading to better outcomes (23.07 ± 5.98 vs. 22.25 ± 5.58 vs. 19.86 ± 5.37). With regard to the dimension pertaining to physical condition, it was observed that adolescents who followed a medium-quality diet reported better values than those who consumed a lowor high-quality diet. Table 3. Levels of physical self-concept according to diet quality. Diet Quality M SD 95% CI Homogeneity of Variance ANOVA LL UL Lev. Sig. F Sig. GS Low 22.46 a,b,c 5.01 21.95 22.96 0.24 0.787 10.40 0.000 Medium 23.27 a,b,c 4.94 22.93 23.61 High 24.03 a,b c, 4.86 23.57 24.48 SF-G Low 23.28 c 4.96 23.04 23.52 0.69 0.497 8.54 0.000 Medium 21.38 b,c 5.95 20.79 21.98 High 22.22 a,b,c 5.75 21.82 22.61 SF-PA Low 23.07 a,b,c 5.98 22.51 23.63 1.80 0.165 18.24 0.000 Medium 22.25 a,b,c 5.88 21.97 22.54 Children 2021, 8, 901 8 of 15 High 19.86 a,b,c 5.37 19.32 20.40 SF-PC Low 20.64 a,b,c 5.19 20.29 21.00 0.18 0.834 25.24 0.000 Medium 21.97 a,b,c 4.87 21.52 22.43 High 20.82 a,b,c 5.20 20.57 21.07 SF-PAT Low 19.04 a,b,c 5.55 18.48 19.59 1.14 0.319 11.38 0.000 Medium 20.19 a,b,c 5.61 19.81 20.58 High 21.77 a,b,c 5.63 21.25 22.30 SF-PS Low 20.35 a,c 5.68 20.07 20.62 0.04 0.960 13.77 0.000 Medium 20.40 b,c 5.96 19.80 21.00 High 21.26 a,b,c 5.61 20.88 21.65 Note 1: GS, general self-concept; SF-G, general physical self-concept; SF-PA, physical ability; SFPC, physical condition; SF-PAT, physical attractiveness; SF-PS, physical strength. Note 2: a, b, c, Post hoc (Bonferroni)—pairwise between-group comparisons. Note 2: M, Mean; SD, Standard Deviation; CI, Confidence Intervals; LL, Lower Limit; UL, Upper Limit; Lev., Levene-test; Sig., Level of significance; F, F-test. Table 4 presents the outcomes of the bivariate Pearson correlations conducted among the dimensions of self-concept, diet quality and physical activity levels. In relation to physical activity, a positive and direct relationship is shown with all its dimensions, with the highest correlation strength being observed for physical condition. Likewise, this is followed by physical ability, strength, general physical self-concept and physical attractiveness last. The association between quality of the Mediterranean diet and physical self-concept is also demonstrated, with positive correlations in all cases. On this occasion, only low correlation strengths are shown, the highest being for physical condition. Moreover, the lowest correlation strength is given for the general physical self-concept and the general self-concept. The existence of direct relationships among the general physical self-concept and its dimensions should be noted, observing a high correlation with physical attractiveness. Moderate-strength correlations are also shown in the fitness and physical ability dimensions. Finally, it is important to highlight that there is a positive and direct relationship between the quality of the diet and the level of physical activity. Table 4. Bivariate Pearson correlations of physical self-concept with diet quality and physical activity. SF-PC SF-PAT SF-PS SF-G GS DIET PA SF-PA 0.703 ** 0.398 ** 0.581 ** 0.421 ** 0.362 ** 0.153 ** 0.492 ** SF-PC 0.496 ** 0.552 ** 0.503 ** 0.382 ** 0.189 ** 0.528 ** SF-PAT 0.364 ** 0.797 ** 0.644 ** 0.118 ** 0.231 ** SF-PS 0.362 ** 0.246 ** 0.127 ** 0.414 ** SF-G 0.643 ** 0.099 ** 0.248 ** GS 0.126 ** 0.163 ** DIET 0.230 ** Note 1: ** = p < 0.01; * = p < 0.05 Note 2: GS, general self-concept; SF-G, general physical self-concept; SF-PA, physical ability; SF-PC, physical condition; SF-PAT, physical attractiveness; SF-PS, physical strength; PA, Physical Activity. Finally, a univariate linear model was carried out in order to verify the relationship of the analysed variables, considering physical self-concept as the dependent variable (Table 5). Levene’s equality test for the variances determined a value of p < 0.001, rejecting the null hypothesis and assuming differences among the variables. Likewise, the value of R2 was 0.658. This value determines a high percentage of explained variance, making the Children 2021, 8, 901 9 of 15 model valid to explain the dependent variable. In addition, appropriate values were obtained for the significance and effect sizes determined from the eta-squared. The model determines how the dimensions of the physical self-concept, which act as covariates, configure the general physical self-concept. In this case, significance was obtained for physical condition and physical ability, with low effect sizes. On the other hand, physical attractiveness was the main determining variable, with a large effect size. In addition, it should be noted that physical strength was not a determining factor for physical self-concept, since significance was not observed. On the other hand, physical activity and quality of diet were introduced as independent variables. In this case, it was determined that diet did not influence physical self-concept, while physical activity had a moderate effect size. Table 5. Univariate linear model for physical self-concept. Origin Sum of Squares DF MS F Sig. η² Corrected model 39,440.54 153 257.78 21.70 0.000 0.689 Intersection 29 , 700 1 297.00 25.00 0.000 0.016 SF-PA 8881 1 88.81 7.47 0.006 0.005 SF-PC 22,078 1 220.78 18.59 0.000 0.012 SF-PAT 19,775.48 1 19,775.48 1665.16 0.000 0.527 SF-PS 666 1 6.66 0.56 0.454 0.000 PA 1022.27 52 19.65 1.65 0.003 0.054 Diet 3629 2 18.14 1.52 0.217 0.002 PA ∗ Diet 1091.71 95 11.49 0.96 0.569 0.058 Error 17,766.50 1496 11.87 Total corrected 57,207.04 1649 Note 1: DF, Degrees of Freedoom; PA, Physical Activity; MS, Mean Square. 4. Discussion The purpose of the present study was to describe existing relationships among physical self-concept, physical activity engagement and adherence to the Mediterranean diet in an adolescent sample. The study arose out of the interest to better understand the influence exerted by the establishment of healthy habits, whilst also considering the aforementioned health indicators and the way in which they are linked to psychological and physical perceptions of one’s own body. The aim of this was to deepen the analysis of relevant variables and make recommendations to promote the positive development of wellbeing throughout life. In this sense, this research followed a line of high international interest as shown by various studies [13,43,73,74]. The main findings indicated that a positive relationship exists among all of the dimensions of physical self-concept and physical activity engagement, with better outcomes emerging for this dimension of self-perception with increasing sport activity. This coincides with research such as that conducted by Álvarez [75] and Fernández [13] and fulfils the first research hypothesis described above. Likewise, Revuelta [76] demonstrated that these variables share a bidirectional relationship; however, their study indicated a negative association between physical attractiveness and physical activity. In contrast, similar to what was found in the present study, Chacón [77] found a stronger correlation between physical self-concept and physical activity, with the dimension pertaining to attractiveness standing out the most. On the other hand, Muros [60] found a positive relationship between physical condition and physical activity engagement, in addition to a negative relationship between better physical condition and worse body composition. In this instance, females and students who were overweight or obese suffered from a worse physical condition. As another point, with regard to the dimension describing strength,