Resonant frequencies of human organs, tissues, and body parts: a systematic review and meta-analysis

Exposure to mechanical vibrations transmitted to the whole body, known as Whole Body Vibration (WBV), poses significant risks to health and safety, particularly contributing to spinal disorders and lower back pain among workers. To mitigate these risks, estimating the resonant frequencies of human body parts and organs is essential, as vibrations near these frequencies can amplify WBVs' harmful effects. However, despite the topic's importance, a comprehensive review of natural frequencies for several body parts remains, quite surprisingly, lacking. The widely cited work by Rasmussen 1983[1], which underpins current national and international norms, has not been updated in four decades. To bridge this gap, this study systematically reviewed experimentally determined resonant frequencies for various organs, soft and hard tissues, and body parts, as reported in the current scientific literature. Searches were conducted across PubMed, Nature, ScienceDirect, Scopus and ResearchGate, yielding over 2000 peer-reviewed articles, of which 388 were examined in detail, and 96 were included in this paper for the meta-analysis. In particular, the critical review was based on selecting only studies deemed relevant by the Authors, preferring experimental tests (wherever available) over numerical or analytical investigations and discarding results from sources that did not detail enough their study methodologies. Key findings, summarised in tables and commented on throughout this article's main text, are presented alongside a detailed and extended Appendix that describes each study. The new findings indicate that modern studies, which utilise advanced experimental and numerical methods, reveal lower resonant frequencies in several body parts and organs compared to Rasmussen's estimates from 1983. These differences highlight advancements in measurement techniques and provide a refined understanding of human biomechanics under WBV, informing future safety guidelines and research.