Efficacy of progressive exercise snacking for middle-aged and older adults with knee osteoarthritis: a systematic review and meta-analysis.

Abstract

To evaluate the effects of progressive exercise snacking (PES) in middle-aged and older adults with knee osteoarthritis (KOA) using meta-analysis. PubMed, Web of Science, CINAHL, Cochrane Library, and Scopus were searched from inception to October 5, 2025, with additional reference-list screening. Randomized controlled trials (RCTs) assessing PES for KOA were included. Two reviewers independently screened studies using predefined criteria. Data on study characteristics, intervention protocols, outcomes, and adverse events were extracted. Outcomes included pain, joint function, gait performance, and quality of life at 4, 12, and 24 weeks post-intervention. Eighteen RCTs (n = 1200) were included. PES improved pain at short-term follow-up (SMD = -1.09, 95% CI = -1.51 to -0.68; moderate certainty) and enhanced joint function (SMD = 1.31, 95% CI = 0.98 to 1.64; moderate certainty) and quality of life (SMD = 0.97, 95% CI = 0.14 to 1.79; low certainty). At mid-term follow-up, PES improved gait performance (SMD = 0.62, 95% CI = 0.25 to 0.98; low certainty). Meta-regression suggested that benefits for pain, joint function, and gait performance diminished with longer follow-up. Subgroup analyses suggested that larger effects may be associated with shorter intervention duration (≤12 weeks), higher weekly exercise dose (≥300 MET·min/week), and walking as the primary modality. PES did not appear to increase adverse events (RR = 1.80, 95% CI = 0.41 to 2.54, P > 0.05). PES may provide short-term improvements in pain, joint function, and quality of life, and mid-term improvements in gait performance in KOA, but long-term efficacy remains uncertain. Larger, high-quality RCTs with longer follow-up and standardized protocols are needed to confirm long-term effectiveness and safety.