Whole Body Vibration (WBV) Research

There is ample evidence accumulated over the last 30 years, both in animal and human studies that prolonged exposure to vibration can result in bodily damage. Vibration induced injury has been documented in multiple systems, including: the spine causing back pain; the peripheral nervous system resulting in neuropathy, carpal tunnel syndrome, tingling in fingers and/or white finger syndrome; the digestive system; female reproductive system; and the vascular and vestibular systems.
  
There are many applications where vibration plays a considerable role in the work environment. In heavy machinery equipments used for Mining, Construction, and Farming, for example, vibration may be transmitted to the head and neck via the steering wheel and/or arm-rest controls and a relatively rigid upper body. While work has been done towards gaining a better understanding of the relationship between vibration and shock and muscle activity of the back musculature2, relatively little information regarding the activity of neck, shoulder and upper arm muscles is known. Greater muscle activity may lead to greater muscle fatigue – which in turn may be associated with greater risk of injury.  Thus, there is critical need for better understanding of the effect of vibration in work environment.
 
Obtaining data for understanding human responses to more and varied vibrational conditions would be a significant and costly proposition. Development of a more general model of human response would therefore enable shortening the development and testing time needed prior to acceptance of a new technology. The Virtual Soldier Research (VSR) program at the Center for Computer-Aided Design (CCAD) at The University of Iowa is developing new technologies for human modeling and simulation. One of our interests in vibration includes exposures expected from all-terrain vehicles for military and civilian applications for the further development of the VSR project involving our digital human (SantosTM).
 The long-term objective of the research at VSR is the development of an autonomous virtual human (named SantosTM) that can interact with and independently evaluate his surrounding environment. The virtual human can provide a tool to help design new products as well as evaluate ergonomic issues concerning an existing product. In addition, an advanced virtual human will provide a useful mechanism for physiological and musculoskeletal studies.
One of the objectives of VSR is to implement the digital human, SantosTM, to simulate and investigate human discomfort and health aspects under whole-body vibration. There are many occupations when humans are subjected to vibration due to their interaction with mobile machines such as mobile fighting units, construction machines, and farming equipments. This may be particularly important for military and industrial equipment that involves off-road, all-terrain driving. The vibration level, frequency, and the force initiated can significantly affect the operator health and performance.
 
While virtual human modeling is a valuable process for reducing cost and injury risks, this technology needs experimental tools to validate, understand, and enhance the parameters of any prediction. Due to the severity and variety of possible environments and the level of vibration involved with off-road, all-terrain heavy machinery, the VSR team is using motion platforms capable of simulating such complex scenarios. Fig.2 shows one example.