Research Review By Christopher Howard©

Date Posted:

November 2009

Study Title:

Effects of iTonic Whole-Body Vibration on Delayed-Onset Muscle Soreness Among Untrained Individuals

Authors:

Rhea MR, Bunker D, Marin PJ, Lunt K

Author's Affiliations:

A.T. Still University, Mesa, Arizona; European University of Madrid, Madrid, Spain; Southern Utah Physical Therapy, Cedar City, Utah

Publication Information:

Journal of Strength and Conditioning Research 2009; 23(6): 1677-1682.

Background Information:

Muscle soreness is a very uncomfortable, painful, and possibly debilitating result of exercise. Delayed-onset muscle soreness (DOMS) is familiar to all of us, typically peaks within 24-48 hours after exercise, and usually resolves within 5 to 7 days. Symptoms of DOMS include pain, tenderness, swelling, and muscle stiffness. These symptoms are believed to be associated with the inflammatory process as opposed to neural causes. Due to greater sarcomere disruption, it is believed that the eccentric component of exercise is the main cause of DOMS.

The phospholipid bilayer of a cell wall functions to protect the cell and to control membrane permeability. The inflammatory process irritates the phospholipid bilayer and causes several cellular changes. First, calcium accumulates in the cell, which activates phospholipase. Phospholipase activity leads to the production of prostaglandins and leukotrienes. Prostaglandins are directly involved in the pain experienced during DOMS. Leukotrienes function to increase blood supply and attract neutrophils to the site of damage. Neutrophils then produce free radicals, resulting in further damage of the cell membrane. Massage, cryotherapy, stretching, homeopathy, ultrasound, and electrical current modalities have not been shown to be consistently effective in relieving DOMS symptoms.

As the search for an effective treatment continues, some have proposed Whole-Body Vibration (WBV) for reducing or mitigating DOMS. It is believed that WBV may decrease DOMS symptoms by increasing blood flow, increasing flexibility, and inhibiting pain. WBV use has not been studied after strength training as a modality for DOMS reduction. Therefore, the purpose of this research was to examine the efficacy of WBV (used as a massage tool and during flexibility exercise after strength training) to prevent or dampen the perceived pain after strenuous exercise among untrained individuals.

Pertinent Results:

  • Statistical analyses identified a significantly lower level of perceived pain at all post-workout measurement times for the WBV group compared to the FLEX (flexibility only) group.
  • No difference (p > 0.05) existed between groups at the pre-workout measurement time.
  • Perceived pain peaked at 24 hours in the WBV group (40/100). Peak pain in the FLEX group occurred at 48 hours (70/100).
  • In the WBV group pain levels had nearly returned to baseline at 72 hours, while they were still elevated in the FLEX group (34/100).
  • The WBV group experienced peak pain earlier and at a lower level, while the FLEX group experienced peak pain later, a higher amount, and for a longer period of time.

Clinical Application & Conclusions:

This study suggests that WBV may be a useful method of attenuating delayed-onset muscle soreness. However, more research needs to be done to further clarify the optimal treatment protocol as well as the mechanisms by which whole-body vibration reduces perceived pain. In addition, the cost of whole-body vibration platforms is currently prohibitive for many healthcare facilities, so while this method may be effective, it may not be practical.

Study Methods:

Experimental Approach:
Untrained men were subjected to a strenuous, exhaustive exercise session. After the session, perceived pain was measured at various intervals for 3 days. One group performed intermittent bouts of WBV, and stretching (WBV group), while the other group performed static stretching only without WBV (FLEX group).

Subjects:
  • Sixteen adult males participated in this study
  • All subjects had participated in aerobic exercise at least 2 days per week for 3 months before the study.
  • None of the subjects had participated in resistance exercise during that time
Exercise Session:
  • Subjects performed 10 minutes of moderately intense running followed by 10 minutes of static and dynamic flexibility exercises in preparation for exercise.
  • The exercise session consisted of resistance training and repeated sprints.
  • Resistance exercises were performed to failure – 4 sets of 8-10 repetitions with eccentric phase completed in 6 seconds and the concentric performed as fast as possible.
  • Exercises utilized: back squat, leg extension, leg curl, heel raises, and deadlifts.
  • After resistance training, subjects performed 10 maximal effort sprints of 40 yards with 60 seconds of rest between.
  • To end the session, subjects performed 10 minutes of static and dynamic stretching.
Whole-Body Vibration Sessions:
  • Subjects were divided into 2 groups: WBV or stretching only without WBV.
  • The WBV group performed 2 sessions of stretching and massage on the FreeMotion Fitness iTonic vibration platform per day for 3 consecutive days. The first session was performed immediately after exercise and another session was performed later in the day.
  • Each WBV session consisted of 30s of massage (50Hz; amplitude 2 mm) of the gastrocnemius, hamstring, and quadriceps. After the massage session, subjects stood on the platform and performed 60s stretches (35Hz; amplitude 2mm) for the same muscles. Each stretch was repeated twice for a total of 6 minutes of flexibility training.
  • The FLEX group performed 2 stretching sessions per day, similar to those performed by the WBV group except without vibration.
Perceived Pain Measurement:
  • A visual analogue scale (0, no pain to 100, maximum imaginable pain) was used to measure perceived pain. Subjects were instructed to rate the pain in the legs immediately before and at 12, 24, 48, and 72 hours post-workout. Subjects were contacted by telephone as a reminder to complete the visual analogue measure.

Study Strengths / Weaknesses:

This study was very basic, with the only measure of effectiveness based on a visual analogue scale of perceived pain. It would be more beneficial if other measures of muscle damage had been performed. However, this was a good study to prove initial effectiveness that can lead to more research in the future. In addition, this study showed that a fairly simple method can produce significant decreases in delayed-onset muscle soreness.

Additional References:

  1. Bakhtiary, Ah, Safavi-Farokhi, Z, and Aminian-Far, A. Influence of vibration on delayed onset of muscle soreness following eccentric exercise. Br J Sports Med 2007; 41: 145–148.
  2. Cheung K, Hume, P, and Maxwell, L. Delayed onset muscle soreness: treatment strategies and performance factors. Sports Med 2003; 33: 145–164.
  3. Melzack, R and Wall, P. Pain mechanisms: a new theory. Science 1965; 150: 971–979.
  4. Herbert, RD and Gabriel, M. Effects of stretching before and after exercising on muscle soreness and risk of injury: systematic review. Br Med J 2002; 325: 468–468.