Mandarin Chinese Translation and Cross-Cultural Adaptation of the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (Chinese HSS Pedi-FABS)

Abstract

Background:

The Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS), consisting of 8 simple questions, is a useful tool for quantifying children's physical activity for research and clinical practice. Because of cultural diversity and variation in native languages across regions, translation and cross-cultural adaptation of patient-reported outcome measures is required.

Purpose:

To translate, cross-culturally adapt, and validate a Chinese version of the HSS Pedi-FABS questionnaire.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

The HSS Pedi-FABS was translated into Chinese following a standardized 5-step forward-backward protocol, including translation, synthesis, back translation, expert review, and pretesting. Healthy children aged 10 to 18 years completed the Chinese HSS Pedi-FABS along with the Physical Activity Questionnaire for Older Children (PAQ-C) or Physical Activity Questionnaire for Adolescents (PAQ-A) for construct validation. Test-retest reliability was assessed over a 7- to 30-day interval, internal consistency was measured using Cronbach alpha, and construct validity was evaluated using Pearson correlation coefficients.

Results:

A total of 184 children aged 10 to 18 years participated. The Chinese HSS Pedi-FABS demonstrated excellent internal consistency (Cronbach α = .93) and test-retest reliability (ICC = 0.98). Strong correlations were observed with PAQ-C (r = 0.85) in participants aged 10 to 12 and PAQ-A (r = 0.89) in those aged 13 to 18 years, supporting construct validity.

Conclusion:

Our study demonstrated that the Chinese version of the HSS Pedi-FABS is a well-validated and reliable instrument for assessing physical activity among healthy Chinese-speaking children and adolescents. This work will assist future researchers in studying and developing physical activity–related outcome measures for Chinese-speaking children.

Activity level is an important prognostic factor in the assessment of patients with sports injuries. ⁹ An evaluation tool that is easy to use in clinical settings can benefit both clinical practice and related research. In response to this need, the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) was developed. ⁹ The HSS Pedi-FABS consists of 8 simple questions, and it has been validated in athletically active children and adolescents 10 to 18 years old. It can reliably and accurately assess activity level as a prognostic variable in clinical research. ⁹ Previous studies have reported the use of the HSS Pedi-FABS as a valid tool for measuring physical activity levels in a variety of injured youth athletes, not only those with knee injuries. ⁴

Although the Physical Activity Questionnaire for Older Children (PAQ-C) and Adolescents (PAQ-A) were developed to assess physical activity across various settings (school, leisure time, and organized sports),^16,26 their comprehensive format can make them relatively time-consuming to complete. In contrast, the HSS Pedi-FABS focuses specifically on functional performance in sports and recreational activities, offering a more streamlined format that is particularly efficient and valuable in clinical and sports medicine contexts. Because of cultural diversity and variation in native languages across regions, cross-cultural adaptations of questionnaires and patient-reported outcome measures is required. To date, the HSS Pedi-FABS questionnaire has been translated and validated in several languages to accommodate clinical practice and research needs, including Dutch, French, Italian, Japanese, Spanish and Arabic.^{1,3,7,14,17,21}

Since language indirectly reflects culture, using nonvalidated questionnaires that have only been translated without cross-cultural adaptation may lead to misinterpretation, resulting in inconsistent functional scores and reduced credibility.^28,31 Several physical activity promotion programs have been implemented for children and adolescents in regions where Chinese is the native language, including Taiwan and China.^5,20 Therefore, developing a simple, practical, and validated Chinese version of this activity questionnaire is of critical importance. To date, no validated Chinese version of the HSS Pedi-FABS questionnaire has been developed. Thus, the purpose of this study was to translate, cross-culturally adapt, and validate a Chinese version of the HSS Pedi-FABS questionnaire. We hypothesized that the Chinese version of the HSS Pedi-FABS questionnaire would demonstrate acceptable reliability and validity as a tool to quantify activity levels in Chinese children and adolescents.

Methods

Prior to the translation process, permission to adapt the HSS Pedi-FABS into Chinese was obtained from the original developers. ⁹ The study was approved by the institutional review board of National Cheng Kung University Hospital, Tainan, Taiwan, and all participants, with parental written informed consent, assented to the study prior to participation.

Translation and Cross-Cultural Adaptation

The English-to-Chinese adaptation was carried out in accordance with the standardized 5-step forward-backward translation protocol described in the Guidelines for the Process of Cross-Cultural Adaptation of Self-Report Measures. ² The procedure comprised translation, synthesis, back translation, expert committee review, and pretesting.^{2,6,8,10,25,31}

The first step was forward translation from English to Chinese. This was carried out independently by 2 native Chinese speakers: 1 informed translator (J.-H.W., an orthopaedic surgeon) and 1 uninformed translator (R.-T.T., a medical student). The second step was cross-cultural adaptation. A cross-cultural discrepancy was identified in the initial translation. The term "pivoting" is difficult for older children to understand; therefore, we chose a more colloquial expression rather than a technical term in the translation—namely, “turning your body or changing direction while keeping one foot in place.” The third step was backward translation from Chinese to English, which was completed by a native English speaker with translation experience after a Chinese consensus version had been finalized. The fourth step involved revision by an expert committee. Both the forward and the backward translations were subsequently reviewed and revised by an expert committee consisting of 3 orthopaedic surgeons (including a professor in the Department of Orthopaedic Surgery) (C.-K.H., C.-A.S., J.-H.W.), 1 physical therapist, and 2 nurses (C.-H.W. and S.-Y.L.). No significant discrepancies or language difficulties were identified in either version, and the preliminary Chinese HSS Pedi-FABS was thus formed during the committee meeting. Finally, the Chinese HSS Pedi-FABS questionnaire was administered to 10 children (4 from elementary school and 6 from high school) to identify any issues with comprehension or completion. No difficulties were reported, and the final version of the Chinese HSS Pedi-FABS questionnaire was established (Appendix 1). The final Chinese version was sent to the original developer ⁹ for review and approval (Appendix 2).

Study Population

In the present study, 200 healthy children aged 10 to 18 years were recruited from the sports teams of 3 elementary schools, 2 middle schools, and 2 senior high schools across multiple cities and counties, covering both urban and suburban areas. This broader geographic sampling may enhance the generalizability of the findings to similar populations in the region. A total of 13 participants who did not complete the questionnaires were excluded. Three children who sustained an injury during the test-retest period were also excluded. Consequently, the final sample size was 184 children.

Each participant completed the Chinese version of the HSS Pedi-FABS, along with one of the following Chinese questionnaires for assessing construct validity: PAQ-C ³³ or PAQ-A. ²⁴ PAQ-C was administered to participants aged 10 to 12 years, whereas PAQ-A was used for participants aged 13 to 18 years. Both questionnaires were self-administered and had been validated for assessing physical activity levels. The same participants completed a second administration of the Chinese HSS Pedi-FABS for test-retest reliability, at an interval of 7 to 30 days.

Reliability

A reliability analysis was conducted to assess test-retest reliability and internal consistency of the Chinese HSS Pedi-FABS questionnaire. Test-retest reliability was determined by asking the participants to complete the questionnaire twice at an interval of 7 to 30 days, which is considered appropriate based on the guidelines for cross-cultural adaptation. ³¹ The intraclass correlation coefficient [ICC(3,1)] was calculated to assess test-retest reliability, where ICC(3,1) represents a 2-way mixed-effects model with single measurements. An ICC of 0 indicates no agreement, whereas an ICC of 1 indicates perfect agreement. In general, ICC values >0.60 and 0.74 are considered indicative of good and excellent reliability, respectively. ¹⁸

Internal consistency was assessed using Cronbach alpha, a widely recognized statistical measure for evaluating the internal consistency of a questionnaire.^30,31 A Cronbach alpha value of .7 is generally considered indicative of acceptable internal consistency among questionnaire items. Values between .70 and .79, .80 and .89, and >0.90 are interpreted as fair, good, and excellent, respectively. ³¹

Validity

To evaluate the construct validity of the Chinese HSS Pedi-FABS questionnaire, the translated and validated versions of the PAQ-C ³³ and PAQ-A ²⁴ were used in the validation process. The Pearson correlation coefficient was calculated to assess the relationship between the Chinese HSS Pedi-FABS and the PAQ-C for participants aged 10 to 12 years, as well as between the Chinese HSS Pedi-FABS and the PAQ-A for participants aged 13 to 18 years. Statistical analyses were performed using SPSS 22.0 (IBM Corp.) and Excel 365 (Microsoft Corp.), with 2-tailed P≤ .05 considered statistically significant.

Psychometric Analysis

Floor and ceiling effects were examined to evaluate the distributional properties and responsiveness of the HSS scores. The presence of these effects was determined by calculating the proportion of participants who achieved the lowest or highest possible total score on the HSS. When >15% of respondents achieved either the minimum or maximum possible score, the measure was considered to exhibit a significant floor or ceiling effect, respectively.^19,29

The standard error of measurement (SEM) and minimal detectable change (MDC) at the 95% confidence level (MDC₉₅) were also analyzed. ¹¹ The SEM was calculated using the formula SEM = SD ×√(1 − ICC). The MDC₉₅ was calculated as MDC₉₅ = SEM × 1.96 ×√2. The MDC₉₅ represents the minimal amount of change required to exceed measurement error with 95% confidence, indicating true change beyond random measurement variation.^11,12

Exploratory Factor Analysis

The exploratory factor analysis used the principal axis factoring extraction method with oblimin rotation, given the expected intercorrelations among questionnaire items. Sampling adequacy was examined using the Kaiser-Meyer-Olkin (KMO) measure, and the Bartlett test of sphericity was applied to verify the factorability of the correlation matrix. Factors with eigenvalues >1 were extracted, and the scree plot was inspected to determine the dimensionality of the scale. To further evaluate measurement consistency, separate analyses were conducted for participants aged 10 to 12 years and 13 to 18 years.

Results

Of the 200 participants recruited, 184 (mean age, 14.1 ± 2.3 years; range, 10-18) with complete responses were analyzed in the present study. The participants’ characteristics are presented in Table 1. Of the total, 50 participants were aged 10 to 12 years, and the remaining 134 were aged 13 to 18 years. Descriptive statistics for each item of the HSS Pedi-FABS are summarized in Table 2. Participants were predominantly aged 14 to 15 years, with a smaller proportion aged 13 years (Figure 1). The distribution of sports activities among male and female participants is shown in Figure 2. The most common sports activities were basketball (23%), baseball (15%), and walking for exercise (11%). These findings indicate that most participants engaged in moderate- to high-intensity sports involving running and pivoting, which are consistent with the activity types assessed by the HSS Pedi-FABS.

Table 1

Characteristics of Participants ^a

	Total(N = 184)	Male(n = 116)	Female(n = 68)
Age, y	14.1 ± 2.3	13.9 ± 2.4	14.5 ± 2.1
HSS Pedi-FABS b (range, 0-30)
First test (age, 10-12 y)	19.7 ± 7.0	20.5 ± 6.6	17.9 ± 7.7
First test (age, 13-18 y)	11.3 ± 8.4	13.8 ± 8.7	7.6 ± 6.2
Second test (age, 10-12 y)	19.9 ± 7.1	20.9 ± 6.5	17.5 ± 8.0
Second test (age, 13-18 y)	11.4 ± 8.2	13.7 ± 8.6	7.9 ± 6.3
PAQ-C (age, 10-12 y)(range, 0-5)	3.2 ± 0.8	3.2 ± 0.8	3.0 ± 0.7
PAQ-A (age, 13-18 y)(range, 0-5)	2.4 ± 0.8	2.6 ± 0.8	2.0 ± 0.8

a

Data are presented as mean ± SD. HSS Pedi-FABS, Hospital for Special Surgery Pediatric Functional Activity Brief Scale; PAQ-A, Physical Activity Questionnaire for Adolescents; PAQ-C, Physical Activity Questionnaire for Older Children.

b

HSS Pedi-FABS ranges from 0 to 30, with higher scores indicating greater physical activity levels.

Table 2

Descriptive Statistics for Each Item of the HSS Pedi-FABS ^a

Items of the HSS Pedi-FABS	Ages 10-12	Ages 13-18
Running: running while playing a sport or jogging	3.4 ± 0.9	2.4 ± 1.2
Cutting: quickly changing directions while running	2.3 ± 1.4	1.4 ± 1.4
Decelerating: coming to a quick stop while running	1.9 ± 1.4	1.5 ± 1.5
Pivoting: turning your body with your foot planted (for example: skiing, skating, kicking, throwing, hitting a ball)	2.8 ± 1.6	1.2 ± 1.5
Duration: perform athletic activity for as long as you would like to without stopping	2.9 ± 1.4	2.0 ± 1.4
Endurance: perform athletic activity for 1 whole hour without stopping	2.7 ± 1.5	1.4 ± 1.5
Competition: do you participate in organized competitive sports or physical activities?	1.6 ± 0.7	0.8 ± 1.1
Supervision: do you participate in supervised (coach, trainer, instructor) sports practice or activities (other than gym classes)?	2.1 ± 1.2	0.7 ± 1.2

a

Data are presented as mean ± SD. HSS Pedi-FABS, Hospital for Special Surgery Pediatric Functional Activity Brief Scale.

Figure 1.

The age distribution of the enrolled participants.

Figure 2.

Distribution of both male and female participants’ sports activities.

Internal Consistency and Test-Retest Reliability

Cronbach alpha value was 0.93, indicating excellent internal consistency. The Cronbach alpha values were 0.92 and 0.94 for male and female participants, respectively, and 0.93 and 0.93 for participants aged 10 to 12 and 13 to 18 years, respectively, indicating uniform internal consistency among subcohorts.

The mean interval of the test-retest process was 11 ± 3.9 days (range, 7-18). The overall ICC was 0.98 (95% CI, 0.98-0.99; P < .01) for the total HSS Pedi-FABS score, indicating excellent test-retest reliability. The ICCs for male and female participants were 0.98 (95% CI, 0.98-0.99) and 0.98 (95% CI, 0.97-0.99), respectively. The ICCs for participants aged 10 to 12 and 13 to 18 years were 0.99 (95% CI, 0.98-0.99) and 0.98 (95% CI, 0.97-0.99), respectively, indicating uniform excellent test-retest reliability among subcohorts.

Validity

For participants aged 10 to 12 years, the HSS Pedi-FABS score was strongly correlated with the PAQ-C score (r = 0.85; P < .001) (Figure 3). Among male participants in this age group, the correlation was r = 0.88 (P < .001), whereas among female participants it was r = 0.82 (P < .001). For participants aged 13 to 18 years, a similarly strong correlation was observed between the HSS Pedi-FABS score and the PAQ-A score (r = 0.89; P < .001) (Figure 3). Among male participants in this age group, the correlation was r = 0.92 (P < .001), whereas among female participants it was r = 0.85 (P < .001).

Figure 3.

Scatterplots showing the relationships between the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) and the Physical Activity Questionnaire for Older Children (PAQ-C) (left) and the Physical Activity Questionnaire for Adolescents (PAQ-A) (right).

Floor and Ceiling Effects

For participants aged 10 to 12 years, the mean HSS Pedi-FABS score was 19.7 ± 7.0 (range, 2-29) for the first survey and 19.9 ± 7.1 (range, 2-29) for the second survey. A total of 4.0% of respondents achieved the minimum possible score, and 6.0% reached the maximum score for both assessments, indicating no significant floor or ceiling effects (both <15%).^19,29 For participants aged 13 to 18 years, the mean HSS Pedi-FABS score was 11.3 ± 8.4 (range, 0-30) for the first survey and 11.4 ± 8.2 (range, 0-30) for the second survey. The proportions of respondents achieving the minimum and maximum scores were 6.7% and 1.5%, respectively, for both assessments. These findings also indicate no evident floor or ceiling effects according to the conventional 15% criterion.^19,29

SEM and MDC

For participants aged 10 to 12 years (n = 50), the SEM values were 0.69 for the first Pedi-FABS score and 0.70 for the second score, with corresponding MDC₉₅ values of 1.92 and 1.95, respectively. For participants aged 13 to 18 years, the SEM values were 1.18 for the first score and 1.16 for the second score, with MDC₉₅ values of 3.26 and 3.23, respectively. These MDC₉₅ values represent the threshold beyond which observed changes can be considered true changes rather than measurement error.

Exploratory Factor Analysis

For participants aged 10 to 12 years, the KMO measure was 0.822, and Bartlett test of sphericity was significant (P < .001), indicating that the data were suitable for factor analysis. One factor with an eigenvalue >1 was extracted, explaining 52.2% of the total variance. For participants aged 13 to 18 years, the KMO measure was 0.851, and Bartlett test of sphericity was also significant (P < .001). A single factor with an eigenvalue >1 was extracted, accounting for 60.3% of the total variance. In both age groups, the scree plot revealed a clear single-factor pattern, supporting the unidimensional structure of the Chinese HSS Pedi-FABS across different age subgroups.

Discussion

The primary finding of the present study was that the Chinese HSS Pedi-FABS demonstrated excellent test-retest reliability (ICC = 0.98), internal consistency (Cronbach α = 0.93), and validity (r = 0.85 and 0.89 with the PAQ-C and PAQ-A, respectively) among healthy young athletes. The HSS Pedi-FABS scores were significantly correlated with previously validated questionnaires for evaluating physical activity (the PAQ-C and PAQ-A). Although the PAQ-C and PAQ-A have been translated into Chinese and validated,^24,33 their major disadvantage lies in the complexity of the questionnaires. Since the HSS Pedi-FABS consists of only 8 questions and is easier to administer, ⁹ the validated Chinese version developed in the present study may serve as a useful tool for assessing sports-related activity levels in healthy youth populations.

Engagement in physical activity is fundamental to the physical, psychosocial, and cognitive health of school-aged children and adolescents^15,23 and may even benefit academic performance. ²² Previous studies have indicated that overall physical activity and participation in organized sports among children and youth are low in both Taiwan ⁴ and China, ²⁰ while sedentary behavior is relatively prevalent. Several factors have been proposed to explain this phenomenon, including the limited number of children's playgrounds due to rapid industrialization, prolonged television-watching time, and parental concerns that extracurricular activities may interfere with academic performance.^5,20,32 As future efforts continue to focus on increasing participation in physical activity among children and adolescents, ²² we believe that the simple and validated Chinese HSS Pedi-FABS developed in the present study will support promotional and educational programs aimed at increasing physical activity in this population.

The findings of the present study indicated that boys had higher physical activity scores, including HSS Pedi-FABS, PAQ-C, and PAQ-A, compared with girls. This pattern is consistent with reports from other Asian countries. In a study from Taiwan, the proportion of male adolescents engaging in sports on weekends was approximately 10% to 15% higher than that of their female counterparts across elementary, junior high, and senior high school students. ²⁷ In China, boys were generally more likely than girls to meet the recommended levels of physical activity and were consistently more active.^13,20 Similarly, in Japan, school-aged boys tend to be more active than girls. ¹⁴ While this is not an unexpected finding in the current study, future studies should aim to investigate the underlying causes of sex differences in physical activity participation in Asian countries and explore strategies to reduce this disparity.

The findings of the present study showed that the HSS Pedi-FABS scores in children aged 13 to 18 were lower than those in children aged 9 to 12. Similar findings have been reported in a Chinese national database. ²⁷ It has been reported that the major barrier preventing students from participating in sports is time. ²⁷ This phenomenon may be attributed to greater academic pressure on high school students, which reduces the amount of time they can devote to sports. In the present study, the validity performance in these 2 age groups was good, suggesting that the Chinese HSS Pedi-FABS is suitable for both highly active and relatively less active populations.

The present study validated the Chinese HSS Pedi-FABS as a practical tool for assessing physical activity in children and adolescents. Boys reported higher activity scores than girls, consistent with previous findings,^13,14,20,27 and a relative difference in scores was observed compared with the PAQ-C and PAQ-A, with correlations slightly weaker for girls. This may reflect sociocultural participation patterns or differences in item interpretation, suggesting the potential value of sex-specific normative data. The Chinese version demonstrated psychometric properties comparable with the original English ⁹ and other translated versions,^1,14,17 with minor differences in factor loadings possibly reflecting cultural variations in sport participation. Overall, these findings support its use for evaluating preinjury status, monitoring recovery, and guiding return-to-sport decisions, while highlighting the importance of considering sex in score interpretation and the potential role of objective measures in future research.

Limitations

The present study had some limitations. First, the sex distribution was not balanced. This study adopted a voluntary participation system; therefore, the sex ratio of the participants could not be precisely controlled. Second, given that Chinese is widely spoken in diverse regions such as Taiwan, China, Hong Kong, Macau, and parts of Southeast Asia, careful consideration is required when applying the translated questionnaire in this study. The current Chinese version of the HSS Pedi-FABS was validated in Taiwan, and it may require adjustment for use in other regions. Although variations in terminology may exist across regions, the HSS Pedi-FABS is comprised of 8 straightforward questions with minimal use of specialized terms, suggesting that its application is unlikely to present substantial difficulty. Third, the study assumed that children's activity levels would remain consistent between the first and second questionnaire administrations. Any unrecognized changes in physical activity would have, if anything, reduced test-retest reliability; however, in this study, the results still demonstrated excellent reliability. Fourth, only healthy individuals were enrolled in the present study, limiting applicability to clinical populations such as injured athletes and postsurgical patients. Fifth, no objective activity measures (eg, accelerometers or pedometers) were used to validate the questionnaire. Additionally, as a self-reported tool, the HSS Pedi-FABS is subject to recall and social desirability biases, particularly among organized sports participants. Sixth, only a single back translator was used, which may introduce some translation bias, although expert review and pretesting were performed to help minimize this risk.

Conclusion

The current study demonstrated that the Chinese version of the HSS Pedi-FABS is a validated and reliable instrument for assessing physical activity among healthy Chinese-speaking children and adolescents. This work will assist future researchers in studying and developing physical activity–related outcome measures for Chinese-speaking children.