Functional Exercise Capacity and Exploratory ICF-Aligned Interpretation of the Incremental Shuttle Walk Test in...

Children with asthma may experience functional exercise limitations that are not fully reflected by resting lung function or conventional clinical assessments. Field-based exercise tests provide complementary information regarding functional capacity, and the International Classification of Functioning, Disability and Health (ICF) offers a biopsychosocial framework to contextualize activity limitations. However, the integration of objective exercise performance with ICF-aligned interpretation in pediatric asthma remains limited.

To interpret functional exercise capacity in children with asthma using Incremental Shuttle Walk Test (ISWT) performance through an exploratory operational framework conceptually aligned with ICF activity qualifiers and to examine its association with lung function, asthma control, quality of life, and demographic characteristics.

In this cross-sectional study, 39 children with asthma (mean age 8.6 ± 2.3 years) underwent spirometry, completed the Asthma Control Questionnaire (ACQ-6) and the Pediatric Asthma Quality of Life Questionnaire (PAQLQ), and performed the ISWT. Functional exercise capacity was expressed as a percentage of predicted ISWT distance and interpreted using an exploratory operational framework conceptually aligned with generic ICF activity qualifiers, generating two categories of activity limitation (mild/moderate and severe).

Resting lung function was relatively preserved (mean FEV₁ 82.0 ± 16.4% predicted), whereas functional exercise capacity was markedly reduced (mean ISWT 41.4 ± 18.7% predicted). Based on the exploratory ICF-aligned framework, 72% of participants were categorized as having severe activity limitation. Children with severe limitations walked significantly shorter distances than those with mild/moderate limitations (32.0 ± 11.5% vs. 65.3 ± 10.1% predicted; p < 0.001), with a very large effect size. Spirometric indices, asthma control, and quality of life scores did not differ between functional categories. ISWT performance was not correlated with lung function, asthma control, or quality of life and demonstrated a negative association with age.

Children with asthma may present substantial functional exercise limitations despite relatively preserved lung function and similar levels of asthma control and quality of life. The exploratory operational alignment of ISWT performance with generic ICF activity qualifiers may provide a clinically useful framework to support interpretation of activity limitations not captured by conventional assessments. However, this approach should be interpreted cautiously and requires future validation before broader clinical application.