Test-retest reliability and minimal detectable change scores of twelve functional fitness tests in adults with Down syndrome.
All 12 functional fitness tests are reliable enough to track real change in adults with Down syndrome—use the provided MDC90 values to decide if a score shift is genuine.
01Research in Context
What this study did
The team gave 12 everyday fitness tests to adults with Down syndrome twice, one week apart. They wanted to know if scores stayed the same when nothing changed.
Tests included walking six minutes, standing up from a chair, and gripping a dynamometer.
What they found
Every test scored an ICC above 0.9. That means the tests are steady enough to spot real change, not noise.
The authors also give MDC90 values. Use these cut-offs to decide if a later score is truly better or worse.
How this fits with other research
Robertson et al. (2013) mapped the same South African group three years earlier. They showed low leg strength; H et al. now prove the tests are reliable, so you can safely track gains after training.
Wouters et al. (2017) found good reliability in kids with mixed intellectual disability. H et al. match that quality in adults with Down syndrome, filling the adult reliability gap.
Moya et al. (2022) later showed only the 10RM seated-squat picks up strength gains in ID adults. Pair their result with H et al.'s MDC90 numbers to choose both a sensitive test and a clear change threshold.
Why it matters
You can now test an adult with Down syndrome, re-test after therapy, and trust a change above the MDC90 value. No more guessing if a smaller walk distance or weaker grip is real or just measurement wobble. Use the provided cut-offs in your next six-minute walk or chair-stand assessment to set goals and show parents or funders solid evidence of progress.
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02At a glance
03Original abstract
AIM: The purpose of the study was to explore the test-retest reliability and minimal detectable change of selected functional fitness test items in adults with Down syndrome. METHODS: Forty-three adults with Down syndrome (24 men and 19 women) aged 18-50 years completed a battery of tests twice in a two-week period. The battery of tests consisted of two balance items, two flexibility items, five muscular strength and endurance items, two aerobic items, and one functional task. All items were considered valid and reliable tests in a general elderly or intellectually disabled population. The test-retest relative reliability for all repeated tests was assessed with intraclass correlation coefficient performing one-way analysis of variance. The test-retest absolute variability was measured by using the standard error of measurement (SEM) to calculate the minimal detectable change at the 90% confidence interval (MDC90). Reliability data was visualised with a Bland-Altman plot. RESULTS: All tests showed excellent intraclass correlation coefficients (ICC's>0.9). All SEM values demonstrated acceptable measurement precision (SEM<SD/2). Values for MDC90 are provided for all 12 tests. The analyses indicated that there was no major systematic bias in the plots. The scatter around the Bland-Altman was distributed randomly. CONCLUSION: All twelve functional fitness tests demonstrated adequate feasibility and relative and absolute test-retest reliability in adults with Down syndrome in South Africa. Information of this nature will help to monitor performance alterations over time and success of training interventions.
Research in developmental disabilities, 2016 · doi:10.1016/j.ridd.2015.10.022