INTRODUCTION

Low physical fitness is considered one of the main risk factors for cardiovascular diseases, surpassing classic factors such as dyslipidemia, high blood pressure and obesity ¹ . Consequently, its assessment is of interest to public health worldwide ² .

However, the assessment of physical fitness components depends on laboratories, the presence of specialists, high funding and time to perform tests, which makes its measurement on a large scale and use in population studies impractical ^2,3 . In this sense, there is a need to seek alternative methods, such as questionnaires, which are widely used in epidemiological research due to their simplicity of use and low cost ⁴ .

However, it is necessary that these instruments present psychometric qualities that guarantee the reliability of the evaluated indicators, with validity being one of the most important, since it analyzes whether the instrument is capable of assessing what it proposes ⁴ . Content validity verifies whether the approach represents the behavior of the sample to be assessed, determining whether the choice of items that make up the instrument is appropriate ⁴ .

Thus, the International Fitness Scale (IFIS) questionnaire was developed and tested in European adolescents, with the objective of self-reporting general physical fitness and its components (cardiorespiratory capacity, muscular strength, speed/agility and flexibility) ² . It was subsequently validated in different populations (children, young people and adults of both sexes; and women with fibromyalgia) ^5,6,1,3 , proving to be valid and reliable, in addition to having shown an association with health parameters ^6,5,1 .

Therefore, given the difficulty in assessing the physical fitness of adolescents in Brazil, as well as the scarcity of alternative methods in the country, cross-cultural validation for Brazilian Portuguese and investigation of the validity and reliability of the IFIS questionnaire are essential. Thus, the objective of the present study was to perform cross-cultural adaptation through translation, content validation, clarity and comprehension of the IFIS questionnaire.

METHODS

Initially, the author’s authorization was requested for cross-cultural validation of the IFIS questionnaire. After obtaining, digitally, the consent form from Francisco B Ortega Ph.D, from the University of Granada , Spain, the cross-cultural adaptation of The International Fitness Scale questionnaire was carried out based on the steps described by Beaton et al. (2000) ⁷ .

a) Translation: two Brazilian sworn translators, officially proficient in English, registered with the Commercial Board of the State of Pernambuco (JUCEPE), independently translated the instrument from English into Brazilian Portuguese;

b) Synthesis of the translation: after the translation, a meeting was held between the researchers and the translators to compare the original version and the versions of each translator. The team identified discrepancies, analyzed the wording, the use of language and the equivalence of the meaning of the questions and answers, seeking consensus and obtaining a single version, preserving the meaning of the original instrument;

c) Back translation : based on the version constructed in the synthesis of the translation, two native North American translators, proficient in Portuguese and who were not familiar with the original version of the instrument, independently translated it back into the original language of the instrument. This stage aimed to check validity, seeking to ensure that the translated version reflects the content of the original version, identifying possible incorrect interpretations and adaptation failures to different cultural contexts;

d) Back-translation synthesis: following the back-translation, a meeting was held between the researchers and the translators, with the aim of selecting the most appropriate and best-expressed phrases. After consensus, the final version of the back-translation was obtained;

e) Review by a committee of experts: a committee formed by five experts proficient in English and Brazilian Portuguese, graduated in Physical Education, PhDs in Psychology, Nutrition, Human Movement Sciences and Public Health, with an average experience of eight years in this type of study and with the researched topic. In order to achieve cross-cultural equivalence, the experts, in possession of all versions (original, translation synthesis and back-translation synthesis), assessed the following equivalences: semantic (identifies whether the word has the same meaning as the original version), idiomatic (evaluates colloquial language that is difficult to translate), cultural (evaluates the cultural context of the target population) and conceptual (evaluates the conceptual meaning of words when they are similar and compares cultural contrasts).

The cross-cultural equivalence of the four areas assessed by the experts was carried out using a Likert scale : 1 – I completely disagree; 2 – I partially disagree; 3 – Indifferent; 4 – I partially agree and; 5 – I completely agree. If the expert did not understand the question or the language did not seem appropriate, he or she was asked to suggest changes, justifying the reasons.

Considering the review and suggestions of the experts, the final version of the instrument to be tested in Brazilian Portuguese was prepared.

f) Assessment of clarity and level of understanding: in order to assess the clarity and level of understanding of each question and the instructions of the scale, the questionnaire was evaluated by 25 health professionals (physical education, nursing, physiotherapy, nutrition and psychology).

Each professional answered the following question: “Did you understand what was asked?”. The answers were on a Likert scale : 1 – I did not understand at all; 2 – I understood only a little; 3 – I understood more or less; 4 – I understood almost everything, but I have some doubts; 5 – I understood perfectly and I have no doubts. If the professional did not understand the question or the language did not seem appropriate, he or she was asked to suggest changes, justifying the reasons. Finally, the final version of the instrument was prepared. All procedures were followed and applied as described by Reichenheim and Moraes (2007) ⁸ and Conti et al. (2009) ⁹ .

g) Pre-test: to assess whether the adapted instrument retains equivalence in the context in which it is being applied in terms of cultural adequacy, comprehension, clarity of questions and answers, errors and difficulties encountered, the final version of the IFIS questionnaire was administered to 40 male and female high school students aged 15 to 17 (Figure 1). The recommended sample size for this stage is five to eight volunteers per number of items or manifest variables ⁷ . All adolescents agreed to participate voluntarily and were selected in a simple random manner.

All procedures adopted in this study followed the Ethics Criteria for Research involving Human Beings, according to Resolution No. 466 of December 12, 2012, of the National Health Council and were approved by the Research Ethics Committee of the University of Pernambuco – Brazil, obtaining opinion under number = 3,015,407 and CAAE = 93550718.0.0000.5207.

DATA ANALYSIS

The data were processed and analyzed in Microsoft Office Excel for Windows software , being entered through double typing and a posteriori checking . Descriptive analyses were developed (mean, standard deviation and median). To evaluate the construct that the instrument proposes to measure and the quality of the translation, the following were used: 1) the mean, with a value above 80% of the Likert scale being considered adequate (ideal value ≥ 4.0) and; 2) the Content Validity Coefficient (CVC), which aims to quantify, examine and interpret the clarity and coherence of each item of the instrument that was proposed by the final version of the expert committee ¹⁰ . The CVC was calculated for each of the aspects judged in the adaptation (semantic, idiomatic, cultural and conceptual) and the CVC for each item of the scale. To consider the quality of the aspect or item judged, a CVC value ≥ 0.80 was accepted as a criterion ¹⁰ .

The verification of the degree of internal consistency of the questions was performed using Cronbach’s alpha coefficient, considering very low (α ≤ 0.30), low (α 0.30 ≤ 0.60), moderate (α 0.60 ≤ 0.75), high (α 0.75 ≤ 0.90) and very high (α > 0.90) ¹¹ . To assess the discriminatory capacity of the IFIS between the physical fitness of boys and girls, we used the Mann-Whitney U test and the effect size, represented by Pearson’s correlation coefficient r, considering as: small effect (r = 0.10), medium effect (r = 0.30) and high effect (r = 0.50) ¹² .

RESULTS

Translation and cultural adaptation

The synthesis of the translation was prepared according to the cultural context and the consensus of the translators with the researchers, with the following adaptations being suggested: in the title – “Self-reported physical preparation”; in the statement – translation of the word ” fitness ” as “preparo” and not as “condicionamento”; in the grading of the answers – ” very poor , poor and average ” were translated, respectively, as “muito mau, mau and média”; question 02 – the term ” cardiorespiratory fitness ” was translated as “preparo física cardiorespiratório”, but the translation as “capacidade cardiorespiratória” was considered more appropriate in the study area.

The back-translation synthesis followed the same patterns as the previous stage, suggesting the following changes: statement – the expression “muito importante” was translated as ” very important “; the word “questionário” was translated as ” questionnaire “; the expression ” by yourself ” was replaced by ” on your own “; the word “mark” was translated as ” check “; and the expression ” try to ” was removed from the back-translation. In the statement and in the first question, the word “preparation” was translated as ” fitness “; in question 02, the word “capacity” appears twice and was translated as ” capacity ” and ” ability “, respectively; in question 03, the word “muscular” became “muscular”; in question 04, the word “is” was translated as ” is “; in the grading of the answers, the options “muito ruim”, “ruim” and “regular” became, respectively, as ” very poor “, ” poor ” and ” average “. The original version and the versions of the synthesis of the translation and back-translation are presented in Table 1.

In possession of the original versions, the synthesis of the translation and the back-translation, the expert committee assessed the semantic, idiomatic, cultural and conceptual equivalence, in which only the idiomatic and conceptual equivalences related to the title presented results lower than 80% on the Likert scale (Table 1). For the final version, the change of the expression ” physical fitness ” was accepted, which had been translated as “physical preparation”, and the expression “physical aptitude” was suggested because it represents the literal meaning of the proposal, and because “physical preparation” is understood as a process and not as a product.

Content Validation

The total Content Validity Coefficient, considering the average CVC for each of the four aspects assessed (semantics, idiomatics, culture and conceptual) was 0.94, above the established cut-off point. After review by the expert committee, adaptations of some expressions and the value of CVC _i for each aspect assessed, the final version of the instrument was prepared (Table 2).

Clarity and degree of understanding

Regarding the degree of clarity and verbal understanding of the final version of the questionnaire evaluated by health professionals, the average value obtained was 4.74, higher than 80% of the Likert scale . Considering the total CVC of the instrument (CVC _t = 0.95) and for each item evaluated (CVC _i ), all scores were above the established cutoff point (Table 3).

Regarding the professional areas (physical education, nursing, physiotherapy, nutrition and psychology), it can be seen that the evaluation of all obtained CVC _t and CVC _i greater than or equal to the established cut-off point, with CVC _i varying between 0.80 and 1.00 (Figure 2).

To perform the pre-test, the final version of the IFIS questionnaire translated into Brazilian Portuguese was administered to 40 adolescents, 21 of whom were female (52.5%) and 19 were male (47.5%), with a mean age of 16.33 ± 0.69 years.

The internal consistency of the IFIS, assessed by the total Cronbach’s alpha coefficient, was 0.88, which is equivalent to high internal consistency. If any item were excluded, Cronbach’s alpha would range from 0.84 to 0.88. However, even if this were to occur, regardless of the item, internal consistency would remain high (Table 4).

Regarding the adolescents’ IFIS responses according to sex, we found that there was a significant difference between them and in all variables (p<0.05), which demonstrates that the instrument has the capacity to discriminate between the different sexes (Table 5 and Figure 3).

In addition to statistical significance, the results obtained from the adolescents’ IFIS responses obtained the average effect size (r) for all items, being: general physical fitness = 0.35; cardiorespiratory capacity = 0.42; muscular strength = 0.42; speed/agility = 0.40 and; flexibility = 0.36.

DISCUSSION

This is the first study to translate into Brazilian Portuguese an instrument capable of assessing general physical fitness and its components, and which presents a strong correlation with adiposity and risk of cardiovascular diseases in children and adolescents ¹ . Therefore, the results of this study allow researchers and health professionals to use this tool associated or not with complementary physical tests, being able to propose national reference scales according to age, sex and level of trainability, and to stimulate the development of government programs that promote the quality of life of this population.

Studies that address the assessment of adolescents’ physical fitness are scarce in Brazil due to the need for specialized laboratories, high funding and trained professionals. Therefore, it is essential to seek easy-to-use and low-cost tools that enable its assessment. Thus, the use of the IFIS questionnaire, originally validated in English, followed by translation into nine languages ​​(German, Austrian German, Greek, Flemish, French, Hungarian, Italian, Spanish and Swedish) ² , is a viable alternative for application in Brazil.

The essence of the present study ensures the veracity and quality of the instrument, ensuring that the cross-cultural validation process followed the guidelines recommended by Beaton et al. (2000) ⁷ , seeking to meet the psychometric properties, respecting the cultural context and linguistic particularities of the country of origin.

In the translation and back-translation stages, discrepancies were observed in the translators’ versions, making it necessary to discuss some items, adapting them to the target audience. In the translation summary, in the title and statement, the word ” fitness ” was translated as “preparo” and not as “condicionamento”, because it is a term that is easier to understand; in the grading of the answers – ” very poor “, “poor” and ” average ” were translated as “muito mau”, “muito mau” and “médium”, seeking a language more accessible to the respondents; in question 02, the term ” cardiorespiratory fitness ” was translated as “preparo física cardiorespiratório” and “aptidão cardiorespiratória”, however, it was discussed that “capacidade cardiorespiratória” is more appropriate in the study area.

In the back-translation summary, in the statement,the expression “very important” was translated as “very important ” and ” crucial “, but it was argued that ” crucial ” is an “extreme” term; the word “questionnaire” was translated as ” survey ” and ” questionnaire “, the latter being selected because it is more specific for an instrument; the expression ” by yourself ” was replaced by ” on your own “, because it better portrays the idea of ​​the individual performing the task individually; the word ” marque ” was translated as ” check “ and ” mark “, the former being selected because it means ” tick ” and mark the alternative; the expression ” try to ” was removed from the back translation, due to the possible implicit idea that the individual does not know how to think or that there is a doubt in his ability to reflect.

In the statement and in the first question, the word “preparo” was translated as ” fitness “; in question 02, the word ” capacidade ” appears twice and was translated as ” capacity ” and ” ability “, due to their sense of ability; in question 03, the word ” muscular ” was translated as ” muscular ” because it is more suitable to qualify the word successive ” strength “; in question 04, the word “é” was translated as ” is ” because the term that precedes it ( speed/agility ) refers to the same context. Finally, in the scale of responses, “muito ruim”, ruim and regular” were translated, respectively, as ” very poor “, poor and average “, because the term ” poor ” is more pertinent when it comes to health conditions, and ” average ” because it is more appropriate for the proposal.

After the syntheses, the instrument was evaluated by the committee of experts, followed by the evaluation of health professionals. The results regarding semantic, idiomatic, cultural, conceptual equivalence, clarity and comprehension assessed by experts (CVC _t = 0.94 – Tables 1 and 2) and health professionals (mean = 4.14; standard deviation = 0.38 and CVC _t = 0.95 – Table 3), in addition to the suggestions adopted with the approval and consent of all evaluators, demonstrate that the final version of the IFIS for Brazilian Portuguese was relevant and well adapted for the translation and cultural adaptation process, taking into account the qualitative and quantitative analysis.since the quality criterion of the instrument was considered above the value (CVC ≥ 0.80) and 80% of the cut-off point of the Likert scale ¹⁰. Furthermore, these results are corroborated by different areas of health (physical education, nursing, physiotherapy, nutrition and psychology), since they obtained CVC _t above 0.90 (Figure 2).

In the analysis of internal consistency, the instrument presented a value equivalent to high internal consistency. Therefore, the instrument responded satisfactorily, preserving the coherence and integration of the items that compose it. The ability to discriminate physical fitness between sexes corroborates the literature, since changes resulting from puberty hormones responsible for the growth and differentiation of the physical characteristics of boys and girls cause boys to present better physical performance compared to girls ¹³ .

Although several instruments measure the level of physical activity in adolescents, such as the Physical Activity Questionnaire for Adolescents (PAQ-A) ¹⁴ , this study is the first to validate in Brazilian Portuguese a questionnaire with good reliability, reproducibility and easy interpretation, capable of assessing physical fitness.

Limitations and Future Perspectives

Although the final translated version of the IFIS is adequate and coherent within the cultural context of Brazil, it still needs to go through some stages to consolidate itself as a new alternative instrument for measuring physical fitness among Brazilian adolescents. Therefore, to ensure the connection between the theoretical content and the empirical data that express our reality, psychometric studies are needed to test the reproducibility, discriminant capacity, predictive capacity, and applicability in large-scale epidemiological studies.

CONCLUSION

It is concluded that the process of translation and cross-cultural adaptation was coherent and adequate according to the judgment of the committee of experts and health professionals, and based on the application of the IFIS to adolescents.

Thus, it is possible to state that the final version of the IFIS for Brazilian Portuguese (Appendix 1) proved to be valid, according to the quality of content, clarity, comprehension, and internal consistency, presenting adequate conditions to be submitted to the next psychometric analyses, allowing future recommendations for its application to adolescents in Brazil.

NOTE OF ACKNOWLEDGMENTS

The authors would like to thank the translators, expert committee and health professionals who contributed to the preparation of this work.

APPENDIX 1

SELF-REPORTED PHYSICAL FITNESS

It is very important that you answer this questionnaire alone, without taking into account the answers given by your classmates. Your answer will be useful for the advancement of science and medicine. Please answer all questions and do not leave any blank. Mark only one answer per question and, most importantly, be honest. Thank you for your cooperation.

Please try to think about your level of physical fitness (compared to that of your friends) and choose the correct option.

Your overall physical fitness is:
( ) Very poor
( ) Poor
( ) Average
( ) Good
( ) Very good

Your cardiorespiratory fitness (ability to do exercise, e.g., run for a long time) is:
( ) Very poor
( ) Poor
( ) Average
( ) Good
( ) Very good

Your muscular strength is:
( ) Very poor
( ) Poor
( ) Average
( ) Good
( ) Very good

Your speed/agility is:
( ) Very poor
( ) Poor
( ) Average
( ) Good
( ) Very good

Your flexibility is:
( ) Very poor
( ) Poor
( ) Average
( ) Good
( ) Very good