Introduction

Whole Body vibration (WBV) has become a popular training method in recent years. This study investigated the effect of WBV on the length-tension relationship of the ankle dorsi (moving your ankle so that balls of feet raise)  and plantarflexors ( moving your ankle in a way that raises the heal of your foot) as measured by a Biodex dynamometer (Biodex Medical Systems Inc, Shirley, NY).

Methods

Twenty healthy young adult males participated in this study and were exposed to two treatments. The first treatment (non-vibration) involved passive stretching of the plantarflexors at end range of motion for five 1-min bouts.

The second treatment involved the same passive stretch with superimposed WBV (frequency = 26 Hz) for five 1-min bouts on a rotary vibration plate (Galileo 900; Novotec, Pforzheim, Germany). Voluntary range of motion, peak torque, and corresponding joint angle of the plantar and dorsiflexors were recorded pre and post-treatment.

Within-treatment (before and after) and between-treatment (WBV and non-vibration) outcomes were assessed by repeated measures( Multivariate analysis of variance).

Results

No significant changes in the measures of ankle dorsiflexion were found within or between treatments. No significant changes in the measures of ankle plantarflexion were found after the non-vibration treatment. After WBV, however, there was a significant 7.1 degrees shift in the angle (P = 0.001) of peak plantarflexor torque production corresponding to a longer muscle length.

Conclusion

This study shows that stretched human ankle plantarflexors respond to WBV by generating peak voluntary torque at longer muscle lengths. This has possible benefits for the rehabilitation of patients with neuromuscular disorders (e.g., stroke) who experience short ankle flexor resting lengths.

This is the third part in a series about understanding research articles. See Part I here.

Method(s)

The method section of the research report should clearly explain how the study was conducted. However, for the layperson, this will be the most difficult section to read. The methods section may be divided into subsequent sub-headers, such as: participants (subjects), equipment, procedure(s), and data analysis.

Participants
This section is presented to give readers a basic overview of the participants and is typically done in terms of age, gender, height, weight and other demographic characteristics of value. Many times participant demographics are presented in the form of a table to enhance viewing. If a particular characteristic (e.g. disease of osteoporosis, status as an elite athlete) is required for inclusion in the study, those criteria for inclusion should be explained. It is preferred that groups of participants are not different (especially significantly) from each other; however, when comparing men and women, many of these differences are inherent.

Selection of participants is very important to the study; how participants are selected and how many are selected can have major impacts on the research quality. Terms like “randomly”, “counter-balanced”, and “cross-over” usually indicate a better research design. “Randomized” means that participants are a representative sample of the larger population and the other two terms show that the research design has controlled for uncontrollable differences in participants. The size of the sample also plays a role in the research quality. Generally, smaller samples provide less knowledge about the general population. While there are statistical analyses to correct for small sample sizes, it is generally thought that individual studies or groups within a study should be no smaller than 8-10 individuals.

In all likelihood, the participant sample will be comprised of individuals who the investigator has easy access too. This is typical of the university study that recruits students. However, the results from a research study are not as easily applied to the general population since the sample was not randomly selected from the general population. The reader should be weary of results that are generalized beyond the sample of the study.

Equipment
The equipment used to provide treatment or measure variables should be described in great detail. While most non-scientific readers will generally ignore this section, those interested in Whole Body Vibration (WBV) will want to be sure to see which vibration machine was used for training or treatment.

Procedure(s)
This section should explain, in detail, how the steps of the study were performed, the order in which they were performed, and how the data were collected. Readers who have a clear idea of how the research was conducted may also have a clear idea of how to apply the results or determine if they can accept the author’s conclusions. Readers should be satisfied the changes noted during the study are the result of the device(s) being studied and not the result of a sloppy procedure.

While this section is very important to researchers, it is another section that is often overlooked by laypeople. The items that non-scientists will want to take note of (specifically those interested in WBV) are specific exercises and vibration characteristics (frequency, amplitude, acceleration/g-force/magnitude/intensity, duration of exposure, number of reps, rest time etc).

Data Analysis
The data analysis section is typically filled with statistical language not understood unless the reader has taken a statistics course. The item that should be paid attention to though, is the p-value. A p-value (or alpha [a]) of 0.05 is most commonly used. This means that there is a 5% chance of error in the results (i.e. the results happened by chance). Whereas, use of a p-value of 0.10 means that there is a greater chance of an error and the use of p=0.01 indicates only 1% error. Most studies will indicate whether or not their results were equal to or less than a certain p-value.

Results

The results section should be solely the results of the data analysis, absent of commentary about those results. This section will typically indicate if a measure was statistically significant (i.e. their results were less than their selected p-value). This is very important; however, some results may statistically significant but not practically or clinically significant.

For example, an increase in vertical jump height of 2 mm is not very practically significant, especially if it is over a long period of time. While there are much more detailed items that could be scrutinized in this section, these are the most important to those without an advanced knowledge of statistics. Non-scientific readers should concentrate on the tables and graphs instead of the statistical jargon in writing. This will help the reader understand the results of the study better without getting lost in the language.

Discussion

In the discussion, the author should cite the main findings if the study and whether or not those findings accepted or rejected the hypothesis. Discussions of the reasons for the results should be extensive and discussion in this section should be tied to the introduction. While reviewing this section, readers should think back to the logic of the arguments presented and consider the issues related to the original problem. Has the author discussed broader implications of their findings? Readers should use this section to able to judge the knowledge and insight of the investigator.

Readers also should be wary of unsupported discussion and conclusions based on insignificant results (e.g. stating that if more data were collected, the results would become significant). Drawing conclusions from future experiments is fraught with suspicious bias. Most research is not of a dramatic, profound, profession-changing nature and usually creates more questions than it answers. Readers must judge if the researcher has conducted fair and objective research.

Since all research has limitations, these should be discussed. Limitations of the study may be presented as an independent section, but are many times also discussed throughout the text of the discussion section. A quality study is always presented with its limitations whether or not they are inherent in the design or procedures.

Lastly, the author should provide a basis on which to apply future research and directions that are important for future research to pursue.

Conclusion

The conclusion section of a research article contains a brief restatement of the experimental results and describes the implications of the study. The conclusions should not be taken outside of the context of the study. Most research studies are very specific in what they are looking at, so application to large-picture ideas is difficult. Remember that the reader’s understanding of the conclusions should be related to the study design, results, and discussion. An attempt to be a neutral reader should be made so that preconceived notions have limited affect on interpretation.

Happy Reading!

References

1. Lunsford, T.R. and Lunsford, B.R. (1996) Research Forum—How to Critically Read a Journal Research Article. Journal of Prosthetics & Orthotics 8(1):24-31 (Accessed at http://www.oandp.org/jpo/library/1996_01_024.asp).

2. Accessed at http://unilearning.uow.edu.au/reading/1d.html.

3. Accessed at http://www.brockport.edu/sociology/journal.html.

This is the second part in a series about understanding research articles. See Part I here.

What is a Research Article?

A research article is one that is published by a peer-reviewed, academic journal. An academic journal is a periodical where researchers publish their work.

Most academic journals are peer-reviewed, meaning that a research article is reviewed by other scholars who do similar work and are qualified to review the article. These individuals critique and evaluate the article, asking questions or offering suggestions to improve the article. The most important aspect of this evaluation is the scientific merit, or asking the question “is this study designed to give quality research results and can those contribute to the knowledge about a particular topic?” It is mainly on this basis that a journal will accept or reject a research article.

Many journals reject more than 50% of the articles that are sent to them, but not always based only on scientific merit (i.e. the research doesn’t fit the readership of the journal). Most times an investigator will go through multiple rounds of review in a single journal or in multiple journals. This peer-review process is meant to ensure that only the best, most clearly written and rigorously research articles are published.

Elements of a Research Article

Title
Now this may seem a little far-fetched but the title of an article can be very informative and therefore, it is important. Additionally, it is the first item that is viewed when the article is read, so it can have a small or great impact on the reader. A good titled can draw someone to read the article while a title that is long and filled with technical jargon may motivate the reader to pass over it. A good title should give insight into what (was done), whom (it was done to) and how (it was done).1 Remember though, that a poorly titled article can still contain quality information.

Abstract
The abstract should provide a brief but complete overview of what the research is about, why it was done (purpose), what was done (methods), how it was done (methods), what was found (results), and what those results mean (conclusion). Reading the abstract is the second element that is read by most individuals. It provides an efficient mode of quickly gaining a general understanding in order to determine if an article suits the reader’s needs.

While an abstract can be used as a tool to quickly identify an appropriate article, it should not be used as a substitute for the entire article. A conclusion in the abstract may not provide adequate context, causing the conclusion to be misinterpreted or over-exaggerated. The abstract is only the appetizer in the meal of an article; the meat and potatoes are in the body of the text.

Introduction
Typically, the introduction will contain the following elements or sub-headers: statement of the problem (rationale), literature review (background), purpose of the study, and hypothesis (expected results). These items are presented in a fashion that begins by making general comments and ends with the most specific comments as the introduction progresses

Statement of the Problem
The statement of the problem (or rationale) tells the reader more than what the problem is. It provides a description of the reasons for conduction the study. This section answers the questions: “Why was this study done?”, “Why is it important?”, and “What was the research question?” An example of this is the need for research to increase physical activity and reduce the problem of obesity. The statement of the problem provides the context for the literature review (background).

Literature Review
The literature review should present what information is available on a particular subject and what has been done by researchers in the past. This allows the author to indicate what has been done (or what is known) and what needs to be done (or needs to be known). This is known as a “gap in knowledge”. The investigators, in doing the particular study, have tried to fill this “gap” with the information obtained. This will lead to the purpose of the study (below). The literature review will also provide readers with in information necessary for conceptual support of the methods.

It should also be noted that this section should contain citations that are not more than 10 years old, and preferably much newer than that. In some cases, very old articles are acceptable because they may be considered “classics”, but these should be few and far between. In addition, the reader should remember that a large number of citations in this section do not necessarily make the article a quality one.

Experienced authors will be easy to recognize because they provide a succinct but informative background for their study that is relatively easy to read. This may be a difficult section for laypeople to get through and can be passed over the first time through and article.

Purpose of the Study
The purpose of the study is one of the most important elements of a research article and should be described in a direct, clear statement. It should be contained in one or two sentences and the reader should be able to determine its parts (e.g. find the differences between men and women). These parts should relate directly to what was measured and the conclusions that are made in the end. A purpose statement that is not clear may be indicative of a poorly planned or conducted study.

Hypothesis (Expected Results)
While a hypothesis is not always provided, presentation of one is ideal. Basically, the hypothesis is a statement of the researcher’s expected results. The hypothesis is usually made based on past research results or a tentative theory, not the hopes of the researcher or sponsor. While this hypothesis guides the interpretation of outcomes and conclusions, proper statistical analyses should be able to control (to an extent) the investigator’s inherent bias.

The hypothesis is typically formed in a manner that states that the results will be positive or negative. For example, a hypothesis could read, “WBV will increase vertical jump performance in elite athletes.” In case the reader encounters discussion about a “null” hypothesis, this is the concurrent hypothesis that would state, “WBV will have no effect (positive or negative) vertical jump performance in elite athletes.” Using statistics, the investigators can determine which hypothesis was correct.

Next Part: Explaining the Method – how research is carried out.

This is the first part of a Guide to Reading Research Articles.

Research articles can be very difficult to read. Reading research is a skill that takes quite some time to be proficient at. This is why many people will read the abstract or conclusions of a study apply them with a broad brush, which is inherently invalid.

When attempting to read and understand an article, remember to read the article as a whole. Also, the authors have written it with the audience being scholars and colleagues. Therefore, a certain level of basic knowledge is assumed. Try not to become frustrated when an article to too complicated. You will learn, in time and with much practice, to extract the important aspects of an article without getting lost in the jargon.

What is Research?

Research is defined as a “systematic inquiry or investigation into a subject in order to discover or revise facts, theories, applications, etc (dictionary.com)”. The “systematic” aspect of research refers to how it is designed, which is very important. This is what separates research from other forms of “evidence”. Commonly, these other forms of “evidence” will be used to market a product (e.g. WBV machines). These may include (with descriptions):

Abstract
This is a summary of research but not an entire research article. Many times it is part of a research article published in a peer-reviewed, academic journal.; however, much care must be taken so that only the abstract is not solely relied upon as “evidence”.

Poster
This is usually a beefed-up summary that is presented at a conference by the researcher(s) as a poster. It may or may not be reviewed for quality prior to being accepted for presentation at that conference.

Presentation
This is similar to a poster but is presented in an oral format via software (e.g. Powerpoint). Again, it may or may not be reviewed for quality.

Case Study(ies)
These can be in the form of a single-person case study or a multiple-person case study (small number of people). These are typically not research because they are not systematically designed to answer a question, nor can results from one or a few individuals answer questions related to the general population.

While these are important first steps in the research process, they are no substitute for a research article. Also, these may be published in peer-review, academic journals; however, they are specific to the individual studied and should not be over-generalized.

Testimonial
Of course the most common of these come from celebrities. They are subjective interpretations of personal experiences and are not valid in a context outside of that individual. While they are very important to that individual, it may be that not all people like them will experience the same outcome.

Why do marketers use these? Because they work and help to sell the marketer’s product. Be the weariest of these forms of “evidence”.

Remember that these forms of “evidence” never can be substituted for a full research article in a peer-reviewed, academic journal.

Also, be aware that true research articles may be presented or listed; however, many times these are only loosely related to the product.

For example, a study performed on a different WBV machine than the one being marketed should be questioned. This is especially true when comparing lineal and pivotal studies.

Many marketers also present studies that use direct muscle vibration (very different than WBV) or industrial WBV to increase the number of studies listed under their “research” sections. These are only loosely related to WBV and the reader should be aware that these types of studies are not direct evidence of the treatment’s effectiveness.

Be leery of these marketing practices to pass these “studies” off as “proof” that something is safe or effective since quantity is never a substitute for quality.

Next Part: Understanding the Different Sections of a Research Article.

Personal Trainer Sal Marinello does a (second) thorough debunking of vibration training machines.

In the May 2007 edition of the (NSCA) Journal of Strength and Conditioning Research, there are four studies that deal with the effects of WBV and the results of these studies do little to further the claims of WBVers that this mode of training is suitable for the masses. As a matter of fact these studies should serve to marginalize WBV, as consumers see how ineffective WBV is.

Marinello goes on to explain that only “the infirm” should be exposed to WBV training, and that research doesn’t really support benefits for those “who are in shape”.

The marketing types that are trying to push these ineffective and expensive pieces of equipment on the unsuspecting public will invoke the meaningless intricacies that they alone have developed with regard to the “science” behind the WBV fad.

US independent consumer testing magazine Consumer Reports took the SoloFlex for a test drive and was not impressed.

Take a pass. There was no significant increase in calories burned when standing on the vibrating board. Most users who did more than stand said the WBV didn’t enhance their workout. Some panelists said the board was too small–a few actually fell off. Some also complained of headaches, blurry vision, or back pain

How They Tested

Six people stood on the device for 5 minutes, at medium and high vibration, while a metabolic gas analyzer gauged the calories they burned (our measure of “a good workout”). Six other people performed three Pilates sessions on the board, two with vibration and one without. And we had three experts in the science of human movement assess the studies Soloflex cites to support its claims.

The Response From SoloFlex

Soloflex does not make weight-loss claims for our WBV Platform nor do we suggest that it replace regular exercise except for those who cannot exercise because of physical limitations. [...]

It takes weeks to see the benefits of any type of exercise program. Consumer Reports magazine should do their homework before publishing such nonsense. Supermarket tabloid reporting may be good for increasing circulation for magazines that do not accept advertising but it does not serve consumers. (source)

Reality Check
Spending 5 minutes to test a piece of fitness equipment is pathetic. It’s a bit like doing a set of dumbbell arm curls, then immediately testing for a strength increase… because there is no apparent gain the dumbbells must not work.

On the flip side – and WBV marketing literature that claims instant weight loss benefits is foolish and misleading. The same must surely be said for cardiovascular gains.

SoloFlex claims their vibrating board will “enhance Pilates, Tai Chi, Yoga and all types of stretching, freebody exercises and weight training” – which is so vague as to be almost meaningless.

Here are the findings from a recent detailed 8 month study on a pivotal machine (Gallileo 2000).

1. The study found significantly positive results for Bone Mass Density increase in post menopausal women using pivotal as compared to lineal machines. (4% increase at the hip;other 8 month studies with lineal machines with variety of protocols had given no significant increment in Bone Mass Density – findings of Torvinen et al, 2003).
2. It also found that this Whole Body Vibration (WBV) protocol was superior than 55 minutes of walking + 5 minutes stretching 3 times a week for developing Bone Mass Density.
3. It found this WBV protocol superior to walking for developing a better balance in the subjects (29% for the WBV group and Nil for the walking group).

The amplitude used was 3mm, frequency 12.6 Hz, with static standing with knee flexion at a 60 degree angle, with a graduated increase in training sets starting with 3 sets x 1 minute reaching 6 sets x 1minute, with 1 minute rest in between. Training was 3 times a week.

Points For Discussion

(1) Do the findings and referenced research literature of this study confirm experiential findings that lineal machines do not improve balance in the static standing only position? If so, are there any positions that can be used with a lineal machine to improve balance – for example standing with one leg on the machine and the other on a non-moving stable same height platform?

(2) Similarly, in the standing position only exercise, is there confirmation that in lineal machines the Bone Mass Density does not really increase (what about golgi bodies stimulating bone mineralization as per other studies?)

(3) Researchers here are citing studies that higher frequencies of 35-40 Hz using a pivotal machine 3 times a week with 4-6 sets would be beneficial for the elderly for balance improvement. How does this co-relate with guidelines on this site that recommend pivotal vibrations do not exceed 30 Hz?

Source: Low-frequency vibratory exercise reduces the risk of bone fracture more than walking: a randomized controlled trial–Narcís Gusi, Armando Raimundo, and Alejo Lea.

Article submitted by Green.

A new study has been published in the Journal of Sports Science and Medicine (reference).

The study looked at 6 weeks of Whole Body Vibration training and it’s impact on sprint performance and explosive strength.

Conclusions:

WBV training period of 6 wk, through the muscle contractions it provokes, produced significant positive changes is selected kinematical characteristics of sprint running (step length, step rate and running velocity) and selected explosive strength characteristics (jump height, total number of jumps performed in a period of 30 s) in non experienced sprinters.

The research used a Power Plate machine and 24 young healthy volunteers.

See the full PDF here.

Recently Nick Grantham of the English Institute of Sport reviewed the research on vibration platforms.

He looked at both health, rehabilitation, and performance enhancement. Grantham’s findings were published in the Sports Injury Bulletin.

The final conclusions:

Should we all rush out and buy vibration platforms for our clinics? Despite the mounting body of evidence in support of this modality, the jury is still out. Marco Cardinale and Carmelo Bosco sum it up in their review paper [1], in which they recommend that studies should continue to explore the effects of long-term vibration training on different physiological parameters and should define appropriate training protocols.

The bottom line? There isn’t one. Vibration training could yet be the next big thing; but so far, the men in white coats cannot give us a green light, and anyone using this technique will be doing so with their fingers firmly crossed behind their backs.

[1] Cardinale, M & Bosco, C (2003). The use of vibration as an exercise intervention. Exercise and Sport Science Reviews 31(1): 3-7

Dr Sue Broadbent is a lecturer in exercise prescription at the Institute of Human Nutrition and Health in Wellington, New Zealand. She makes the following statements in New Zealand’s Sunday Star Times.

“There’s some evidence it may improve fitness and yield better results than normal resistance training with weights, but it’s not increasing cardiac fitness at all.

“In other words, it won’t prevent you having a heart attack and it’s not going to help you lose weight or increase your metabolic rate.” From the Sunday Star Times.

Broadbent is heading up reseach commissioned by NZ’s Accident Compensation Comission who funds the rehabiliation of injured athletes.

“There is anecdotal evidence that whole body vibration may reduce inflammation associated with soft tissue injury. But we don’t know if that’s true, or how it’s supposed to work.”