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Whole-body vibration

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Whole body vibration (WBV) is a generic term used when vibrations (mechanical oscillations) of any frequency are transferred to the human body. Humans are exposed to vibration through a contact surface that is in a mechanical vibrating state. Humans are generally exposed to many different forms of vibration in their daily lives. This could be through a driver's seat, a moving train platform, a power tool, a training platform, or any one of countless other devices.[1] It is a potential form of occupational hazard, particularly after years of exposure.

When high frequency vibrations[2] (above 50 Hz) enter through the hands, occupational safety concerns may arise. For example, working with a jackhammer has been known to develop vibration white finger. Exposures and limits have been estimated in the ISO 5349-1 for hand-transmitted vibration.[3]

A 2018 meta-analysis said that whole body vibration can improve bone mineral density in the lumbar spine of postmenopausal women as well as the femoral neck density of postmenopausal women younger than 65.[4]

As a hazard

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Humans are sensitive to mechanical oscillations ranging in frequency from well below 1 Hz up to 100 kHz.[5] Lower frequencies of vibration lead to human motion sickness[6] while higher frequencies can lead to general annoyance and discomfort. The minimization of discomfort due to vehicle vibration is important in the automotive industry where ride quality is important. Discomfort and even pain may be extremely prevalent in situations where medically injured patients are transported. The discomfort due to vibration can be estimated in various environments.[7][8]

Workplace exposure

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X-ray of spondylosis of the lumbar spine.

Workplace exposures to whole-body vibrations for long durations can lead to musculoskeletal problems of many kinds.[9] Problems of the neck and lower back in particular can be common for operators of heavy equipment including construction, forestry, agriculture, and trucking. Other occupations where whole-body vibrations may be present include aircraft operators, sea vessel workers, drivers of public transportation like trains and buses.

Farmers with long-term exposure to whole body vibration and mechanical shocks have a higher prevalence of back pain (compared to those not exposed to vibration), and the prevalence increases with vibration dose.[10] Long-term exposure affecting the whole body leads to spinal degeneration (spondylosis) and increased risk of low back pain.[11][12]

Factors that affect the occupational exposure to whole-body vibration include the frequency of vibrations, the magnitude of vibrations, the daily exposure to vibrations, the standing or seating posture of the operator, the direction of the vibration, and how tightly coupled the human is to the source of the vibration.[13] Exposure limits and estimates have been characterized in the ISO 2631-1[14] for whole-body vibration. Measurements of vibration exposure are usually taken at the human/vibration interface.

Patient transport

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Injured patients can be exposed to shocks and vibrations during transport which can worsen patient conditions due to involuntary motions of the body. Many forms of immobilization devices are used to limit this motion with varying degrees of success.[15][16][17] Common modes of patient transport include hand carried stretcher (litter), ground ambulance, and air medical services which all contain multiple forms of shocks and whole-body vibrations.

Measurement

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Measurements are taken with accelerometers to estimate the amount of vibration exposure to the human body. These measurements are taken at the human body or at the vibration source or surface.[13] Measurements of different directions are taken to relate the motion direction with the response of the human body.[18] Specifically, transfer functions can be used to determine the human response to the vibration.[19] Measurement techniques for estimating exposures to whole body vibrations and hand-arm vibration have been developed in International Standards.[20][3]

Vibration training

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Vibration training is the deliberate exposure to the body of varying frequencies/amplitudes/forces using certain joint angles for any limited time (approximately 1 minute sets). It is also known as vibration therapy, vibrotherapy, biomechanical stimulation, mechanostimulation and biomechanical oscillation. It employs low amplitude, low frequency mechanical stimulation. It can be pivotal/oscillating (vibrating from side to side) or lineal (vibrating up and down).

History

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The immediate predecessor of modern vibration training is Rhythmic Neuromuscular Stimulation (RNS). In then East Germany, Biermann was experimenting with the use of cyclic massage and its effects on trunk flexion as early as the 1960s. [21]

The technique has been tested on turkeys in the hope of finding a benefit that could be used for astronauts.[22] Engineering issues came into play when an attempt was made to upgrade the test machine to support the weight of a human being. Once the vibration intensity grew strong enough to lift over 40 kg, fractures appeared in the steel. The first bed-rest study using a vibration training device for humans was done by the European Space Agency (ESA) in 2003 in Berlin[23] (Berlin Bedrest Study, BBR). The same technology was then used in several parabolic flight campaigns of the DLR (German Aerospace Agency) starting in 2006 where the feasibility of use of a lightweight vibration training device under microgravity conditions was demonstrated and in 2009 and 2010 where basic research on influence of microgravity on vibration training effects was investigated.[24][25]

Training effects

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A 2018 meta-analysis concluded that whole body vibration improved lumbar spine bone mineral density (BMD) in postmenopausal women, and enhanced femoral neck BMD in postmenopausal women younger than 65 years.[4]

A review in 2014 concluded that there is little and inconsistent evidence that acute or chronic whole body vibration could improve the performance of competitive or elite athletes.[26]

Cochrane reviews have concluded that there is insufficient evidence of effect of whole body vibration training on functional performance of people with neurodegenerative disease,[27] or in disease-related problems in people with fibromyalgia.[28]

Some research supports benefits for arthritis[29] and knee pain.[29]

Vibrating platform types

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Vibrating platforms fall into different, distinct categories. The type of platform used is a moderator of the effect and result of the training or therapy performed.[30] Main categories of machine types are:

  1. High energy linear, found mostly in commercial vibration training studios and gyms. The vibration direction is lineal/upward
  2. Premium speed pivotal, (teeter-totter movement) used for physiotherapy work at lower speeds and exercise workouts at "premium" speed, up to 30 Hz. Both commercial and home units are available.
  3. Medium energy lineal, the majority of lineal platforms produced. These are usually made of plastic; some have 3-D vibration which is low quality.
  4. Low speed pivotal units.
  5. Low magnitude mechanical stimulation. They are platforms that use energy levels less than 1 g and typically move in the z-axis.

Other machine types are low energy/low amplitude lineal and low energy/high amplitude lineal.

Concerning the z-movements, two main types of system can be distinguished:[30][31][32]

  • Side alternating (pivotal) systems, operating like a see-saw and hence mimicking the human gait where one foot is always moving upwards and the other one downwards, and
  • Linear systems where the whole platform is mainly doing the same motion, respectively: both feet are moved upwards or downwards at the same time.

Systems with side alternation usually have a larger amplitude of oscillation and a frequency range of about 5 Hz to 40 Hz. Linear/upright systems have lower amplitudes but higher frequencies in the range of 20 Hz to 50 Hz. Despite the larger amplitudes of side-alternating systems, the vibration (acceleration) transmitted to the head is significantly smaller than in non-side-alternating systems[33] while at the same time muscle activation even at identical vibration parameters are increased in pivotal systems.[34] However, standing with both heels on one side of a side-alternating machine facing side-ways results in significant acceleration transmitted to the head and center of gravity of the upper body. At least one such whole body vibration owner's manual suggest this variation calling it "Stand-a-side Pose". At the outer edge of the plate the amplitude is typically about 10 mm, which is more than the 3 mm maximum of a linear vibrator and not practical. The amplitude and impact  can be reduced by centering, e.g., a gardener's knee pad, ~ 16"x 8" x 3/4", on the plate and standing with the heels toward the outer edge of the pad. While this is useful it does not replace a machine whose entire plate moves up and down in a linear fashion allowing for a variety of positions and activities.

Mechanical stimulation generates acceleration forces acting on the body. These forces cause the muscles to lengthen, and this signal is received by the muscle spindle, a small organ in the muscle. This spindle transmits the signal through the central nervous system to the muscles involved.[33][35]

Belts

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A vibrating belt machine (also Mueller belt machine, belt massager, or jiggler machine) is an exercise machine that uses a vibrating belt, to be used around the waist or buttocks.

See also

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References

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  1. ^ Mansfield, Neil J (2005). Human response to vibration. Boca Raton, FL: CRC Press. ISBN 978-0415282390. OCLC 55681295.
  2. ^ Pyykkö I, Färkkilä M, Toivanen J, Korhonen O, Hyvärinen J (June 1976). "Transmission of vibration in the hand-arm system with special reference to changes in compression force and acceleration". Scandinavian Journal of Work, Environment & Health. 2 (2): 87–95. doi:10.5271/sjweh.2820. JSTOR 40964583. PMID 959789.
  3. ^ a b "ISO 5349-1:2001". ISO.
  4. ^ a b Marín-Cascales E, Alcaraz PE, Ramos-Campo DJ, Martinez-Rodriguez A, Chung LH, Rubio-Arias JÁ (August 2018). "Whole-body vibration training and bone health in postmenopausal women: A systematic review and meta-analysis". Medicine. 97 (34): e11918. doi:10.1097/MD.0000000000011918. PMC 6112924. PMID 30142802.
  5. ^ Guignard, J.C. (8 March 1971). "Human sensitivity to vibration". Journal of Sound and Vibration. 15 (1): 11–16. Bibcode:1971JSV....15...11G. doi:10.1016/0022-460X(71)90354-3. ISSN 0022-460X.
  6. ^ Lawther A, Griffin MJ (September 1987). "Prediction of the incidence of motion sickness from the magnitude, frequency, and duration of vertical oscillation". The Journal of the Acoustical Society of America. 82 (3): 957–66. Bibcode:1987ASAJ...82..957L. doi:10.1121/1.395295. PMID 3655126.
  7. ^ DeShaw J, Rahmatalla S (April 2016). "Predictive discomfort of supine humans in whole-body vibration and shock environments". Ergonomics. 59 (4): 568–81. doi:10.1080/00140139.2015.1083125. PMID 26280381. S2CID 21097165.
  8. ^ DeShaw J, Rahmatalla S (August 2014). "Predictive discomfort in single- and combined-axis whole-body vibration considering different seated postures". Human Factors. 56 (5): 850–63. doi:10.1177/0018720813516993. PMID 25141593. S2CID 25403875.
  9. ^ Magnusson ML, Pope MH, Wilder DG, Areskoug B (March 1996). "Are occupational drivers at an increased risk for developing musculoskeletal disorders?". Spine. 21 (6): 710–7. doi:10.1097/00007632-199603150-00010. PMID 8882693. S2CID 21895841.
  10. ^ Solecki L (2011). "[Low back pain among farmers exposed to whole body vibration: a literature review]". Medycyna Pracy. 62 (2): 187–202. PMID 21698878.
  11. ^ Pope MH, Wilder DG, Magnusson ML (1999). "A review of studies on seated whole body vibration and low back pain". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine. 213 (6): 435–46. doi:10.1243/0954411991535040. PMID 10635692. S2CID 29873978.
  12. ^ Wilder DG, Pope MH (March 1996). "Epidemiological and aetiological aspects of low back pain in vibration environments - an update". Clinical Biomechanics. 11 (2): 61–73. doi:10.1016/0268-0033(95)00039-9. PMID 11415601.
  13. ^ a b Griffin MJ (1990). Handbook of human vibration. London: Academic Press. ISBN 9780123030405. OCLC 21591126.
  14. ^ "ISO 2631-1:1997". ISO.
  15. ^ Mahshidfar B, Mofidi M, Yari AR, Mehrsorosh S (October 2013). "Long backboard versus vacuum mattress splint to immobilize whole spine in trauma victims in the field: a randomized clinical trial". Prehospital and Disaster Medicine. 28 (5): 462–5. doi:10.1017/S1049023X13008637. PMID 23746392. S2CID 23650820.
  16. ^ Rahmatalla S, DeShaw J, Stilley J, Denning G, Jennissen C (May 2018). "Comparing the Efficacy of Methods for Immobilizing the Thoracic-Lumbar Spine". Air Medical Journal. 37 (3): 178–185. doi:10.1016/j.amj.2018.02.002. PMID 29735231.
  17. ^ Sundstrøm T, Asbjørnsen H, Habiba S, Sunde GA, Wester K (March 2014). "Prehospital use of cervical collars in trauma patients: a critical review". Journal of Neurotrauma. 31 (6): 531–40. doi:10.1089/neu.2013.3094. PMC 3949434. PMID 23962031.
  18. ^ DeShaw, Jonathan (1 May 2013). New methodologies for evaluating human biodynamic response and discomfort during seated whole-body vibration considering multiple postures (Thesis). doi:10.17077/etd.zp71qekg.
  19. ^ Hinz B, Menzel G, Blüthner R, Seidel H (2010). "Seat-to-head transfer function of seated men--determination with single and three axis excitations at different magnitudes". Industrial Health. 48 (5): 565–83. doi:10.2486/indhealth.MSWBVI-03. PMID 20953074.
  20. ^ "ISO 8041-1:2017". ISO.
  21. ^ Biermann, W. "Influence of cycloid vibration massage on trunk flexion". American Journal of Physical Medicine. 1960 (39): 219–224.
  22. ^ "Good Vibrations". Archived from the original on 29 October 2011.
  23. ^ Rittweger J., Felsenberg D.: Resistive vibration exercise prevents bone loss during 8 weeks of strict bed rest in healthy male subjects: results from the Berlin Bed Rest (BBR) study, 26th Annual Meeting of the American Society for Bone and Mineral Research; October 2004; Seattle
  24. ^ Kramer A, Gollhofer A, Ritzmann R (August 2013). "Acute exposure to microgravity does not influence the H-reflex with or without whole body vibration and does not cause vibration-specific changes in muscular activity". Journal of Electromyography and Kinesiology. 23 (4): 872–8. doi:10.1016/j.jelekin.2013.02.010. PMID 23541330.
  25. ^ Ritzmann R, Krause A, Freyler K, Gollhofer A (2016). "Gravity and Neuronal Adaptation - Neurophysiology of Reflexes from Hypo- to Hypergravity Conditions". Microgravity Sci. Technol.
  26. ^ Hortobágyi, Tibor; Granacher, Urs; Fernandez-del-Olmo, Miguel (17 December 2014). "Whole body vibration and athletic performance: A scoping review". European Journal of Human Movement. 33: 1–25.
  27. ^ Sitjà Rabert, Mercè; Rigau Comas, David; Fort Vanmeerhaeghe, Azahara; Santoyo Medina, Carme; Roqué i Figuls, Marta; Romero-Rodríguez, Daniel; Bonfill Cosp, Xavier (15 February 2012). "Whole-body vibration training for patients with neurodegenerative disease". Cochrane Database of Systematic Reviews (2): CD009097. doi:10.1002/14651858.CD009097.pub2. PMID 22336858.
  28. ^ Bidonde, Julia; Busch, Angela J; van der Spuy, Ina; Tupper, Susan; Kim, Soo Y; Boden, Catherine (26 September 2017). "Whole body vibration exercise training for fibromyalgia". Cochrane Database of Systematic Reviews. 2017 (9): CD011755. doi:10.1002/14651858.CD011755.pub2. PMC 6483692. PMID 28950401.
  29. ^ a b Wang, Pu; Yang, Xiaotian; Yang, Yonghong; Yang, Lin; Zhou, Yujing; Liu, Chuan; Reinhardt, Jan D; He, Chengqi (October 2015). "Effects of whole body vibration on pain, stiffness and physical functions in patients with knee osteoarthritis: a systematic review and meta-analysis". Clinical Rehabilitation. 29 (10): 939–951. doi:10.1177/0269215514564895. PMID 25525066. S2CID 4144638.
  30. ^ a b Marín, Pedro J; Rhea, Matthew R (March 2010). "Effects of Vibration Training on Muscle Power: A Meta-Analysis". Journal of Strength and Conditioning Research. 24 (3): 871–878. doi:10.1519/JSC.0b013e3181c7c6f0. PMID 20145554. S2CID 34125166.
  31. ^ Rittweger, Jörn (March 2010). "Vibration as an exercise modality: how it may work, and what its potential might be" (PDF). European Journal of Applied Physiology. 108 (5): 877–904. doi:10.1007/s00421-009-1303-3. PMID 20012646. S2CID 571476.
  32. ^ Rauch, F.; Sievanen, H.; Boonen, S.; Cardinale, M.; Degens, H.; Felsenberg, D.; Roth, J.; Schoenau, E.; Verschueren, S.; Rittweger, J.; International Society of Musculoskeletal and Neuronal Interactions (1 September 2010). "Reporting whole-body vibration intervention studies: Recommendations of the International Society of Musculoskeletal and Neuronal Interactions". Journal of Musculoskeletal & Neuronal Interactions. 10 (3): 193–198. PMID 20811143.
  33. ^ a b Abercromby AF, Amonette WE, Layne CS, McFarlin BK, Hinman MR, Paloski WH (October 2007). "Vibration exposure and biodynamic responses during whole-body vibration training". Medicine and Science in Sports and Exercise. 39 (10): 1794–800. doi:10.1249/mss.0b013e3181238a0f. PMID 17909407.
  34. ^ Ritzmann R, Gollhofer A, Kramer A (January 2013). "2013 The influence of vibration type, frequency, body position and additional load on the neuromuscular activity during whole body vibration.". European Journal of Applied Physiology. 113 (1): 1–11. doi:10.1007/s00421-012-2402-0. PMID 22538279. S2CID 17554617.
  35. ^ Burkhardt A.: Vibrationstraining in der Physiotherapie - Wippen mit Wirkung, Physiopraxis 9/06, s.22.25, 2006

Further reading

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