Handgrip strength measurement protocols in individuals with Down syndrome: a systematic review and meta-regression.

Background: Handgrip strength (HGS) serves as a robust predictor of overall strength across various populations, including individuals with Down Syndrome (DS).

Objective: To analyze the HGS measurement protocols used in studies involving individuals with DS.

Methods: Primary sources were sourced from six databases: PubMed, Scopus, Ovid, Embase, ERIC, and Web of Science, spanning from inception to 23rd December 2023. Inclusion criteria focused on individuals with DS, compared with control groups, and examined HGS measurement protocols and outcomes. Meta-regression was utilized to assess bias associated with HGS values concerning different measurement protocols.

Results: Out of 29 studies involving 1816 participants, most controlled for body position (65%), arm position (82%), elbow position (82%), wrist position (62%), handgrip duration (55%), hand adjustment to dynamometer (62%), verbal encouragement (75%), and familiarization (44.8%). The number of reported variables in the HGS protocol was significantly associated with an increase in HGS, with a mean estimate of 20.59 units (SE = 2.59, p < 0.0001, 95% CI [15.49-25.68]), though there was notable heterogeneity (I² = 94.33%). The spline regression analysis showed that the model explained 82.66% of the variation in HGS, with adults having 47.61 units higher HGS than children (p = 0.0009), while obesity was linked to a decrease of 15.68 units (p = 0.0675). Sample size and group had no significant effects.

Conclusion: Overall, protocols for assessing HGS in DS studies are comprehensive yet heterogeneous. Higher HGS values correlated with adherence to standard protocols.