Editor’s Note: We are pleased to present another guest post by Dr. Lon Kilgore. Today’s Kilgore article looks at the risks of vibration plate training. It continues the theme developed by John Weatherly. Weatherly’s vibration plate articles (Part 1, Part 2) exposed the unreliable research the National Strength and Conditioning Association published on its sponsor Power Plate.
What do we really want to do with vibration devices? They’ve been in and out of fashion since Kellogg’s painful vibrating chair in the 1880’s but if vibration truly drove fitness gain, wouldn’t every truck driver and machine operator be a pinnacle of fitness? And doesn’t vibration carry with it a documented risk of injury?
It is no secret that the NSCA has made some relatively stern, and public, statements that paint CrossFit as a purveyor of unsafe and ineffective exercise training. For example,
An additional concern with ECPs is the risk of injury …
In summary, though ECPs such as CrossFit and P90X are very popular, this popularity does not appear to be warranted. There is little evidence from peer-reviewed studies that ECPs are safe and/or effective
Let’s counterpoint this treatment to how the NSCA approaches another trendy exercise modality, vibration training.
First, we need to set the table. Vibration training involves a trainee standing on, or exercising on a large vibrating plate. Some models of this equipment type have handlebars to hold, other models do not. The basic concept here is the strong vibrations, delivered at frequencies between 10 and 60 Hz, are applied to the human body and cause the mechanoreceptors (sensory nerves) in the muscles to fire, causing muscular contraction on a fairly large scale. This muscular activity, with no exercise, is proposed to drive fitness. If you can simply stand on a vibrator and get fit, why wouldn’t everyone do that? Especially since the NSCA blesses vibration training as safe and effective to use in every warm-up session:
it can be recommended that if practitioners have access to a WBV platform that it can be used within a warm-up protocol …
There was an increase in flexibility and power output
This position is interesting in the context of the background literature regarding vibration exposure and the human body. When a human body is exposed to vibration, the symptoms are immediate and related to vibration frequency (hertz or Hz):
- 4-8 Hz – Influence on breathing movements
- 4-9 Hz – General feeling of discomfort
- 4-9 Hz – Muscle contractions
- 4-10 Hz – Abdominal pains
- 5-7Hz – Chest Pains
- 6-8 Hz – Lower Jaw symptoms
- 10-18 Hz – Urge to urinate
- 12-16 Hz – “Lump in throat”
- 13-20 Hz – Head symptoms
- 13-20 Hz – Influence on speech
- 13-20 Hz – Increased muscle tonus
Vibrating the entire body repeatedly over time has also been documented to produce some fairly deleterious effects:
- 10 Hz – Inner ear damage
- 20 Hz – Organ resonance
- 30 Hz – Nerve damage
- 10-30 Hz – Blurred vision
- 50 Hz – Loss of visual acuity
- 30 and 60 Hz – Arterial damage
The risk of permanent damage from vibration is related to the amount of vibration exposure, with long or repeated exposures carrying the highest probability of injury. It is a telling indictment that the NSCA endorses regular use of an exercise modality that has enough documented hazard that the US Occupational Safety and Health Administration, via ANSI and ISO standards, and the European Parliament have recommendations in place to monitor and limit vibration exposure.
Regular exposure to whole-body vibration in the workplace has been described as a cause for:
- Low back pain
- Neck and shoulder disorders
- Digestive disorders
- Circulatory disorders
- Cochleo-vestibular disorders
- Possible reproductive issues
- Vehicular safety hazard (loss of vehicle control)
How broadly scoping potential for injury arises can be represented as in the graphic below:
While most of the concern about whole body vibration is in the workplace, the use of vibration devices in the fitness environment carries the same risks.
In fact, Clinton Rubin, Distinguished Professor and Chair of the Department of Biomedical Engineering at SUNY, has written that
The magnitudes used in those devices [referring to commercially available vibration devices for fitness] well in excess of 8.0G, are well beyond the limits recommended for human tolerance by ISO and OSHA, are 35 times greater in amplitude than those mechanical signals that we study, are inherently dangerous, and to our knowledge, show little if any evidence that their devices are safe for the bone, cartilage, muscle, tendon, ligaments or any of the major organs.
Is it strange that the NSCA recommends an “exercise” modality that has a trainee placed on and potentially exercising on top of an apparatus that confounds neuromotor feedback and defeats spinal reflexes, reflexes intended to ensure our safety and function? What possible rationale could a professional organization have to take such a cavalier position in this instance while singling out CrossFit, whose safety has been shown to be as safe, or safer, than weight training, soccer, cheerleading, and virtually all other training modalities? http://www.nsca.com/about-us/support-and-sponsors/
Should the NSCA executive group take it upon themselves to drive the creation of materials for public consumption that inequitably and potentially wrongfully promote or deter use of any exercise modality? Should the NSCA membership demand accountability for the actions of their executive group?
These are valid questions that must be answered in order for the NSCA to rightfully occupy their self-proclaimed niche as the “world authority” on strength and conditioning.
Leahy, G. Evidence-Based Physical Training: Do CrossFit or P90X Make the Cut. http://www.nsca.com/education/articles/evidence-based-physical-training-do-crossfit-or-p90x-make-the-cut/
National Strength & Conditioning Association. Is whole-body vibration training effective for golfers? http://www.nsca.com/education/articles/is-whole-body-vibration-training-effective-for-golfers/
Rasmussen G. (1983). Human body vibration exposure and its measurement. Journal of the Acoustical Society of America, 73(6): 2229.
Occupational Safety and Health Administration. OSHA Technical Manual (OTM) Section II: Chapter 3 [Updated 02/11/2014] https://www.osha.gov/dts/osta/otm/otm_ii/otm_ii_3.html#WholeBodyVibration
American National Standards Institute. ANSI S3.18:2002 (adoption of ISO 2631-1). International Organization for Standardization. ISO 2631-1:1997 (Mechanical vibration and shock: Evaluation of human exposure to whole body vibration—Part 1: General requirements); http://webstore.ansi.org/RecordDetail.aspx?sku=ANSI%2fASA+S2.72-2002%2fPart+1+%2f+ISO+2631-1%3a1997+%28R2012%29
European Parliament. Directive 2002/44/EC. Minimum health and safety requirements regarding the exposure of workers to the risks arising from physical agents (vibration). http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32002L0044&from=EN
Muir J, Kiel D, and Rubin C. (2013). Safety and severity of accelerations delivered from whole body vibration exercise devices to standing adults. Journal of Science and Medicine in Sport, 16(6): 526–531.
Rubin, C. (2006). Contraindications and Potential Dangers of the Use of Vibration as a Treatment for Osteoporosis and other Musculoskeletal Diseases. http://www.bme.sunysb.edu/people/faculty/docs/crubin/safety-1-11-06.pdf
Seidel H (2005). On the relationship between Wholebody Vibration Exposure and Spinal Health Risk. Industrial Health, 43: 361-377
About the Author:
Professor Lon Kilgore graduated from Lincoln University with a bachelor of science in biology and earned a Ph.D. in anatomy and physiology from Kansas State University. He has competed in weightlifting to the national level since 1972 and coached his first athletes to national-championship event medals in 1974. He has worked in the trenches, as a coach or scientific consultant, with athletes from rank novices to professionals and the Olympic elite, and as a collegiate strength coach. He has been a certifying instructor for USA Weightlifting for more than a decade and a frequent lecturer at events at the U.S. Olympic Training Center. His illustration, authorship, and co-authorship efforts include the best-selling books “Starting Strength” (first and second editions) and “Practical Programming for Strength Training” (first and second editions), recent releases “Anatomy Without a Scalpel” and “FIT,” magazine columns, textbook chapters, and numerous research journal publications. He is presently engaged in the most difficult task of his career: recreating the educational track to becoming a professional fitness practitioner. The second stage of this effort is the creation of a one-year university qualification in fitness practice at the University of the West of Scotland.