Absorbed power characteristics of seated human subjects under fore-aft (x-axis) and lateral (y-axis) vibration are investigated through measurements of dynamic interactions at the two driving-points formed by the body and the seat pan, and upper body and the backrest. The experiments involved: (i) three back support conditions (no back support, and back supported against a vertical and an incli...

www.asse.org JULY 2005 PROFESSIONAL SAFETY 35 WHOLE-BODY VIBRATION (WBV) is the vibration transmitted to a person’s entire body via his/her contact with a vibration source, usually through sitting or standing on a vibrating surface. WBV is a common occupational problem for workers in highvibration environments, particularly when the exposure represents a significant part of their working day, n...

There is strong evidence to suggest that acute indirect vibration acts on muscle to enhance force, power, flexibility, balance and proprioception suggesting neural enhancement. Nevertheless, the neural mechanism(s) of vibration and its potentiating effect have received little attention. One proposal suggests that spinal reflexes enhance muscle contraction through a reflex activity known as toni...

Human health and comfort under whole-body vibration depend on the level, frequency, direction, location, and duration of the acceleration. The international standard ISO 2631-1 [1] specifies a method of evaluation of the effect of exposure to vibration on humans by weighting the root-mean square (r.m.s.) acceleration with human vibration sensitivity curves. There are six frequency-weighting cur...

CONTEXT Whole-body vibration machines are a relatively new technology being implemented in the athletic setting. Numerous authors have examined the proposed physiologic mechanisms of vibration therapy and performance outcomes. Changes have mainly been observed in the lower extremity after individual exercises, with minimal attention to the upper extremity and resistance training programs. OBJ...

To evaluate the effect of short-duration, high-load resistive exercise, with and without whole body vibration on lumbar muscle size, intervertebral disk and spinal morphology changes, and low back pain (LBP) incidence during prolonged bed rest, 24 subjects underwent 60 days of head-down tilt bed rest and performed either resistive vibration exercise (n = 7), resistive exercise only (n = 8), or ...

Vibration exercise (VbX) is a new type of physical training to increase muscle power. The present study was designed to assess the influence of whole-body VbX on metabolic power. Specific oxygen uptake (sVO(2)) was assessed, testing the hypotheses that sVO(2) increases with the frequency of vibration (tested in 10 males) and with the amplitude (tested in 8 males), and that the VbX-related incre...

Human exposure to whole-body vibration (WBV) has been associated with a variety of changes in health, comfort, and occupational functioning. In the C-130J Hercules aircraft, crews from both Australia and overseas have reported that the vibration in the cargo compartment of the aircraft exceeds previous levels and that it is both annoying and fatiguepromoting. This report examines the issue of h...

The report of the World Health Organization (WHO) of 2008 defines osteoporosis as a disease characterized by low bone mass and an increased risk of fracture. Postmenopausal osteoporosis is connected to the decrease in estrogens concentration as a result of malfunction of endocrine ovarian function. Low estrogens concentration causes increase in bone demineralization and results in osteoporosis....

Experimental data collected over the years, for defining limits of vibration exposure to human beings, have resulted in a set of vibration criteria specified in ISO Standard 2631. In this article, instrumentation requirements for evaluation of the responses of humans to vibration according to these criteria are described, as well as some of the pitfalls to be avoided during these measurements. ...