Does Frequency of the Mechanical Vibration Matter? Evaluating the Impact of Whole-Body Vibration Training on Older Adults Strength, Balance, and Gait Performance: A Systematic Review and Network Meta-analysis

Abstract

Objective: To identify the optimal whole-body vibration training (WBVT) mechanical vibration frequency for enhancing muscle strength, static balance, dynamic balance, and gait performance among older adults through systematic review and network meta-analysis. Data Sources: PubMed, Web of Science, Cochrane Library, Embase, and Scopus databases were systematically searched for randomized controlled trials (RCTs) up to December 2024. Study Selection: The RCTs comparing low-frequency WBVT (LF-WBVT, frequency of the mechanical vibration, f<20 Hz), medium-frequency WBVT (MF-WBVT, 20 Hz≤f<30 Hz), and high-frequency WBVT (HF-WBVT, 30 Hz≤f≤40 Hz), and traditional training regarding their effects on strength, balance, and gait in healthy older adults were included. Data Extraction: Methodological quality was assessed using the Physiotherapy Evidence Database scale, and evidence quality was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Continuous data were analyzed as mean differences (MD) or standardized mean differences (SMD) with 95% confidence intervals (CI) using Stata MP 15.1 (StataCorp). Data Synthesis: Twenty-seven RCTs (1608 participants) were included. Ranking probability analysis indicated MF-WBVT was most effective for static balance (surface under the cumulative ranking curve [SUCRA]=98.5%; SMD=2.55; 95% CI, 0.85-4.24), HF-WBVT ranked highest for dynamic balance (SUCRA=75.8%; MD=0.60; 95% CI, 0.12-1.07) and gait performance (SUCRA=85.1%; MD=0.45; 95% CI, 0.15-0.75), and traditional training was optimal for improving muscle strength (SUCRA=80.1%; SMD=0.61; 95% CI, 0.27-0.95). Conclusions: Among the 3 mechanical vibration frequency types examined, HF-WBVT is optimal for improving dynamic balance and gait performance, MF-WBVT is recommended for static balance, and traditional training is preferable for enhancing muscle strength.