Test-retest reliability of static and dynamic motor fatigability protocols using grip and pinch strength in typically developing children.

Upper limb motor fatigability is an important debilitating factor for activities of daily living in clinical pediatric populations. However, the reliability of fatigability protocols in these populations is currently unknown. Therefore, the current study investigates test-retest reliability of a static and dynamic motor fatigability protocol for grip and pinch strength in typically developing children (TDC). Eighty-nine TDC (35 boys, 54 girls; mean age 10 years 11 months) used a grip and pinch dynamometer for static (sustained) and dynamic (repeated) contractions during 30s. For static motor fatigability (SFI), mean (Fmean) and SD (Fvar) of force were calculated, and for dynamic motor fatigability, F mean and number of peaks (Npeaks) were calculated. Intraclass correlation coefficients (ICC) were calculated. ICCs of F mean in static and dynamic motor fatigability were high (ICC: 0.94-0.96 and 0.91-0.98). ICCs were moderate to high for F var (ICC: 0.67-0.85). The SFI showed moderate ICCs (ICC: 0.69-0.77). ICCs were moderate to high for N peaks (ICC: 0.78-0.91).Conclusion: The results suggest that static and dynamic motor fatigability in for grip and pinch can be used reliably in TD children aged 6-18 years. What is Known: •Psychometric properties of motor fatigability protocols using grip and pinch in children are lacking. •Motor fatigability in grip and pinch is an important debilitating symptom in multiple neurologic populations. What is New: •Static fatigability can be investigated using a 30-s maximum sustained grip strength protocol in children. •Dynamic fatigability can be investigated using a 30-s maximum repeated grip strength protocol in children.