The Assessing Levels of Physical Activity (ALPHA) health-related fitness test battery provides a set of reliable, valid, feasible, and safe field-based fitness tests for the assessment of health-related physical fitness in children and adolescents to be used in public health monitoring in a comparable way within the European Union (12). The fitness tests included in the ALPHA health-related fitness battery assess the main components of fitness that have a relationship with health such as (a) cardiorespiratory fitness, (b) musculoskeletal fitness, (c) body composition, and (d) motor fitness.
Down syndrome (DS) is a chromosomal condition caused by an extra copy of genetic material on the chromosome 21, and its estimated prevalence is about 1/1,000 births. Individuals with DS have many features that affect their health and well-being such as brachycephaly, hypotonia, lax ligaments, mental retardation, heart diseases, leukemia, short stature, and obesity (11). Health-related physical fitness in children and adolescents with DS may be an important marker of health in these ages and in later life (8), and thus, reliable fitness tests are necessary. The use of the ALPHA battery would allow, in addition, crossnational comparisons with population-based samples of children and adolescents. Therefore, the aim of this study was to examine the test-retest reliability of the ALPHA health-related fitness test battery in adolescents with DS.
Experimental Approach to the Problem
To investigate the test-retest reliability, 2 complete sets of assessments included in the ALPHA health-related fitness test battery (13) were performed within 1 month. The same conditions were provided in both measurements: duration, schedule, evaluators, settings, and motivation. All measurements were videotaped for checking the precise administration of each test according to the ALPHA battery protocols.
This study included a total of 17 Spanish adolescents (5 girls) with DS, aged 12–18 years (15.4 ± 2.0 years). Inclusion criteria for participation were that the subjects have an intelligence quotient (IQ) >35 and habitual engagement in physical education classes. Before participating, all the parents gave signed written consent. The study was carried out in accordance with Helsinki's declaration, and all the study procedures were approved by the Ethics Committee of the Autonomous University of Madrid.
The evidence-based health-related ALPHA fitness test battery (12) includes the following tests: (a) the 20-m shuttle-run test to assess cardiorespiratory fitness, (b) the handgrip strength and the standing broad jump tests to assess musculoskeletal fitness, and (c) body mass index (BMI), waist circumference, and triceps and subscapular skinfold thicknesses to measure body composition. In this study, we examined the extended health-related ALPHA fitness test battery (12) that additionally includes the 4 × 10-m shuttle-run test to assess motor fitness. Adolescents performed these tests as described in detail elsewhere (12). All standard operation procedures and protocols for fitness testing are available in the manual and videos in the ALPHA project website (https://sites.google.com/site/alphaprojectphysicalactivity/).
In this study, there were 3 nonsignificant adaptations. (a) In the 20-m shuttle-run test, only 1 or 2 subjects performed the test at the same time, and they ran accompanied by one of the evaluators to guide them if necessary. (b) The handgrip strength procedures were slightly modified. Specifically, adolescents performed this test seated in a chair, whereas this test is usually performed in a standing position. We had to use this strategy because these adolescents paid more attention in squeezing the hand dynamometer in a seated position rather than in a standing position. To know whether this modification would allow comparing scores obtained in our population who performed this test seated with scores obtained in adolescents without DS (habitually standing), we conducted a pilot study in Spanish adolescents without DS, aged 11 and 17 years (n = 155, 70 girls). They performed handgrip tests in both positions, that is, seated and standing. We found that there were no significant differences between both positions, and the mean difference for right and left hands was −0.15 kg (95% confidence interval [CI]: −0.60 to 0.29; p = 0.507) and −0.23 kg (95%CI: −0.56 to 0.09; p = 0.160), respectively (unpublished observation). (c) In the standing broad jump test, the participants can do more attempts if they needed it.
With regard to the communication processes and explanation of tests, a direct and simple oral language was used. Also, the evaluators provided visual models and examples before performing the test, when necessary. The participants did not receive specific training on these tests previously.
Analyses were performed using the IBM SPSS software (v.20.0, Chicago, IL, USA), and the level of significance was set at p ≤ 0.05 for all analyses. Values are presented as mean ± SD. Nonparametric Wilcoxon signed rank test was used to compare the mean differences between measurements (test vs. retest). The test-retest reliability of the ALPHA health-related battery was determined by the intraclass correlation coefficient (ICC). The ICC was interpreted as follows: 0–0.2 indicates poor agreement; 0.3–0.4 indicates fair agreement; 0.5–0.6 indicates moderate agreement; 0.7–0.8 indicates strong agreement; and >0.8 indicates almost perfect agreement (10).
All the subjects had moderate intellectual disability (IQ = 35–55), except one of them that had a mild intellectual disability (IQ = 56–70). Two adolescents did not have all the extended ALPHA health-related fitness battery tests. One girl could not use the hand dynamometer because of a disease in the hands. The same girl also could not perform the standing broad jump test. Moreover, it was not possible to measure triceps and subscapular skinfolds in 1 boy because he was uncomfortable with the caliper. Table 1 shows the differences and reliability in the levels of health-related physical fitness between test and retest measurements. There were no significant differences between measurements from the extended ALPHA health-related fitness battery tests (all p > 0.1). In all the tests, we found almost perfect test-retest reliability, with the exception of subscapular skinfold that obtained a moderate agreement (ICC = 0.64). The 3 tests with the best agreement were the following ones: waist circumference (ICC = 0.98), BMI (ICC = 0.95), and the 4 × 10-m shuttle-run test (ICC = 0.92).
The main finding of this study indicates that the extended ALPHA health-related fitness battery is reliable for assessing health-related fitness in adolescents with DS. Although the ALPHA battery was initially developed for children and adolescents without DS, some components of health-related physical fitness such as cardiorespiratory fitness, musculoskeletal fitness, body composition, and motor fitness may be measured with an adequate reliability in this population. These results are important because an early in life monitoring of health-related physical fitness might contribute to substantial improvements in life expectancy and wellness in DS population (11).
The 20-m shuttle-run test is the most widely used field-based test to measure cardiorespiratory fitness in youth (12). We found an almost perfect agreement between test and retest measures in the 20-m shuttle-run test in adolescents with DS. Early studies by Fernhall et al. (3) found that this test was also strongly reliable in 34 youth with intellectual disabilities, including 8 with DS. Later, Mac Donncha et al. (6) also reported an almost perfect agreement (ICC = 0.94) in 65 male adolescents with mental retardation (mean IQ = 63 ± 12). In contrast, Gillespie (4) observed a moderate reliability (ICC = 0.53) in 8-year-old children with intellectual disabilities. Additionally, owing to the low scores obtained in this test, our results suggest that in populations with DS the final score of the 20-m shuttle-run test should be not collected in half stages or seconds, as suggested by the ALPHA health-related fitness battery. Instead, the last completed lap might be easily used to obtain a higher precision in this population (1).
Our results regarding the reliability of the musculoskeletal tests confirm previous studies (5–7,9,13) in populations with intellectual disabilities and DS that also found a high reliability in the upper body and lower body strength tests (ICCs ranging between 0.89 and 0.98).
Test-retest reliability was almost perfect for BMI, waist circumference, and triceps skinfold measures, but subscapular skinfold only obtained moderate reliability. In 1 study in 45 subjects with severe intellectual and sensory disabilities, subscapular skinfold obtained the lowest test-retest reliability (ICC = 0.83) than other anthropometric measures such as BMI, waist circumference, and other skinfolds. In the ALPHA project framework, Artero et al. (2) pointed out that, in general, (a) the reliability is higher for BMI and body circumferences compared with skinfolds; (b) the variability of skinfold measurements is greater when the measures taken are also greater; and (c) the knowledge of the protocols and the years of experience could significantly predict precision and accuracy in measuring skinfold thicknesses.
On the other hand, the reliability of the 4 × 10-m shuttle-run test was one of the highest (ICC = 0.92). Using the same test, Guerra et al. (5) found a similar test-retest reliability (ICC = 0.89) in adults with DS, whereas Mac Donncha et al. (6) obtained an ICC = 0.94 using the 5 × 10-m shuttle-run test in adolescent boys with mental retardation.
In summary, the ALPHA health-related fitness battery is reliable for measuring health-related components of fitness in adolescents with DS and IQ ≥ 35. This finding allows crossnational comparisons with adolescents without DS, even though further studies are needed for examining the validity of these tests in youth with DS.
The ALPHA health-related fitness test battery provides a set of reliable, valid, feasible, and safe field-based fitness tests for the assessment of health-related physical fitness in apparently healthy children and adolescents. In this study, our results confirm that the ALPHA health-related fitness battery is also reliable for measuring health-related components of fitness in adolescents with DS. Hence, adolescents with and without DS might be compared using this standardized and evidence-based health-related fitness battery.
Some guidelines for using the ALPHA health-related fitness test battery in young people with DS should be taken into consideration: (a) It might be necessary to have an inclusion criterion based on the level of intellectual disability; in the study, we included adolescents with DS and IQ ≥ 35. (b) The communication processes and explanation of tests need a direct and simple oral language, and evaluators also must provide a visual example. (c) In the 20-m shuttle-run test, <3 subjects should perform the test at the same time, and they might run accompanied by one of the evaluators to guide them when necessary. (d) The handgrip strength test seems to be more feasible when performed with these participants seated. (e) In the standing broad jump test, the participants could do more attempts.
Further information, including protocols and videos of fitness testing, on the ALPHA health-related physical fitness battery is available in the ALPHA website: https://sites.google.com/site/alphaprojectphysicalactivity/.
The authors gratefully acknowledge the help of all the adolescents who took part in this study, and thank their parents and teachers for their collaboration. They also thank Dr. Jonatan R. Ruiz for his thoughtful commentaries on this report. This study was financially supported by the Spanish Ministry of Science and Innovation (DEP2010-21662-C04) and co-funded by FEDER funds from the European Union.
1. Agiovlasitis S, Pitetti KH, Guerra M, Fernhall B. Prediction of VO2
peak from the 20-m shuttle-run test in youth
with Down syndrome. Adapt Phys Activ Q 28: 146–156, 2011.
2. Artero EG, España-Romero V, Castro-Piñero J, Ortega FB, Suni J, Castillo-Garzon M, Ruiz JR. Reliability of field-based fitness tests in youth
. Int J Sports Med 32: 159–169, 2011.
3. Fernhall B, Pitetti KH, Vukovich MD, Stubbs N, Hensen T, Winnick JP, Short FX. Validation of cardiovascular fitness field tests in children with mental retardation
. Am J Ment Retard 102: 602–612, 1998.
4. Gillespie M. Reliability of the 20-metre shuttle run for children with intellectual disabilities. Eur J Adapt Phys Activ 2: 7–13, 2009.
5. Guerra M, Cuadrado E, Balague N, Canals C, Fernandez R. Validity and reliability of field tests in adults with mental retardation
. In: International scientific meeting at the centenary of the Olympic champion Leon Stukelj “Sport-health-old age”. Sugman R., ed. Ljubljana, Slovenia: University of Ljubljana-Faculty of Sport, 1999. pp. 276–279; Slovenia, 1998.
6. Mac Donncha C, Watson AWS, McSweeney T, O'Donovan DJ. Reliability of Eurofit physical fitness
items for adolescent males with and without mental retardation
. Adapt Phys Activ Q 16: 86–95, 1999.
7. Mercer VS, Lewis CL. Hip abductor and knee extensor muscle strength of children with and without Down syndrome. Pediatr Phys Ther 13: 18–26, 2001.
8. Ortega FB, Ruiz JR, Castillo MJ, Sjöström M. Physical fitness
in childhood and adolescence: A powerful marker of health. Int J Obes (Lond) 32: 1–11, 2008.
9. Pitetti KH, Fernandez JE, Pizarro DC, Stubbs NB. Field testing: Assessing the physical fitness
of mildly mentally retarded individuals. Adapt Phys Activ Q 5: 318–331, 1988.
10. Portney LG, Watkins MP. Foundations of Clinical Research: Applications to Practice. New Jersey, NJ: Prentice Hall Inc., 2000.
11. Roizen NJ, Patterson D. Down's syndrome. Lancet 361: 1281–1289, 2003.
12. Ruiz JR, Castro-Piñero J, España-Romero V, Artero EG, Ortega FB, Cuenca MM, Jimenez-Pavón D, Chillón P, Girela-Rejón MJ, Mora J, Gutiérrez A, Suni J, Sjöström M, Castillo MJ. Field-based fitness assessment in young people: The ALPHA health-related fitness test battery for children and adolescents. Br J Sports Med 45: 518–524, 2011.
13. Waninge A, van der Weide W, Evenhuis IJ, van Wijck R, van der Schans CP. Feasibility and reliability of body composition measurements in adults with severe intellectual and sensory disabilities. J Intellect Disabil Res 53: 377–388, 2009.