Eight (8) men were randomly assigned to a grounded (GRD) or ungrounded (UNG) group (GRD
4). Because of extensive controls and the purpose of the study, only 8 subjects were selected. All subjects were between the ages of 20 and 23 with a body weight between 150 and 175 pounds and a body mass index within the healthy range (18.5–24.9). All subjects were required to complete a medical history to ensure eligibility and that they were free of injuries or disease. All subjects were informed of the purpose/possible risks involved in the investigation and were required to read and sign an informed consent prior to participation. The study was approved by the Human Subjects Committee at the University of Oregon.
In order to control variables, only 1 subject was studied each week, Sunday afternoon through Thursday evening. All markers were obtained at exactly the same time of day (see for a list of all 48 markers). All subjects stayed in the same motel room for the duration of the study, leaving only for tests to which they were driven. They all were provided with equal amounts of identical food. They ate at 8:00 am, 12:00 pm, and 6:00 pm. They were required to be in bed at 9:30 pm and arise at 7:00 am. At 5:40 pm on Monday through Wednesday, subjects were grounded to the earth via conductive patches placed on their gastrocnemius and on the bottom of both feet. They kept the patches on when they went to bed. With the exceptions of bathroom visits and eating, they were required to stay on the grounded sheet. The grounded subjects used grounded patches and sheets, while the ungrounded subjects used patches and sheets whose connections had been modified to prevent a ground connection. This was a double-blind study, and neither the subjects nor the investigator knew the grouping.
Blood markers included a complete blood count, a blood chemistry, creatine kinase, aspartate transaminase, alanine transaminase, alkaline phosphatase, interleukin-6, and serum cortisol. All blood draws were done in the subject's motel room at 8:00 am by a certified phlebotomist from Legacy Laboratories, Eugene, OR. Blood samples were analyzed by Legacy Laboratories.
Magnetic resonance imaging and spectroscopy
All magnetic resonance imaging and spectroscopy was completed each day at 9:00 am
at the Lewis Center for Neuroimaging on the campus of the University of Oregon at Eugene under the direction of Dr. Scott Frey. The sites were the right and left gastrocnemius muscles located in the middle of each gastrocnemius, 8 and 16
cm distal to the knee joint. The subjects were placed in the magnet, a Siemans Alegra 3 Tesla, on their backs with the coils on the selected sites.
Saliva cortisol was collected each morning at 8:00 am by the Legacy Laboratory certified phlebotomist and analyzed by Legacy Laboratories.
Pain was measured subjectively and objectively. The subjects completed the Visual Analogue Soreness Scale each day at 8:00 am and 5:30 pm.
Also at 5:35 pm, the subjects were tested for pain by having a blood pressure cuff placed around their right gastrocnemius. It was slowly inflated until the subject requested that no more pressure be administered due to a feeling of acute discomfort.
Delayed-onset muscle soreness protocol
DOMS is a well-known result of excessive, unfamiliar, or intensive exercise movements. Muscle cell breakdown occurs along the Z-lines, which are the regions where tension developed within the muscle cell is conducted to the myofascial system, and by leakage across cell membranes.5–9
To date, there is no known treatment that reduces the time frame to recovery, but apparently massage and hydrotherapy6–8
can reduce pain. This condition presents in 24–48 hours after the exercise and its duration can last well over 96 hours.9,11
It produces acute inflammation in the muscle(s) affected.5,6,10,11
All subjects were tested Monday between 8:00 am and 9:45 am prior to any DOMS producing contractions. On Monday at 10:00 am, eccentric toe raises were performed, which resulted in DOMS and acute inflammation.
The subjects completed two sets of 20 eccentric toe raises. They placed a barbell equal to one third of their body weight on their shoulders. They then placed the balls of their feet on a stable 2
4, making their toes approximately 2 inches higher than their heels. There was a spotter behind them at all times. On command, they rose up on their toes to a fully extended position and held that position for 10 seconds. At the end of 10 seconds, they lowered their heels to the floor. Upon touching the floor, they rose up to the fully extended position and held it again for 10 seconds. After 20 repetitions, they had a 2-minute rest and then repeated the 20-repetition procedure.
Because the goal of the pilot study was to select markers for further study and because the number of subjects did not lend itself to normal statistical methods, another standard was chosen. The study goal might be met by selecting markers that showed (1) a difference between GRD and UNG that was equal to or greater than 10% and (2) a consistent pattern of one group's results being always above or below the other group for all post-tests.
Total bilirubin is a good example of how the 10% threshold was determined. Genzyme Diagnostics (Genzyme Diagnostics P.E.I. Inc., Charlottetown, Prince Edward Island, Canada) reports that interferences from hemoglobin, lipemia, and ascorbic acid were evaluated for their total bilirubin method on a Hitachi analyzer using a significance criterion of >10% variance from control. Furthermore, the same company presents results of precision studies showing precisions varying from 1.1% to 3.1% and the result from an accuracy study showing an accuracy of 5% based on the slope of the linear regression equation. Because attainment of the markers was timed precisely in order to eliminate circadian rhythms as a confounding factor and all other aspects of their lives were controlled, it was felt that using a criterion twice Genzyme's accuracy result would be conservative, in agreement with their own assessment that a significance criterion of >10% variance was giving them reasonable results. Consequently, we felt that if the two standards listed above were met, these markers would be worthy of further consideration in a study with more subjects.
The 10% or greater difference was determined in the following manner:
- Results for each day (Monday, Tuesday, Wednesday, and Thursday) were averaged for each group.
- Percent differences for each day of each group were calculated with pretest (Monday) values as reference values using the formula: ((post-test/pretest)−1)*100%.
- The difference between groups for each day was determined by subtracting the ungrounded group percent difference from the grounded group percent difference.
Example: Grounded group % difference
7%; Ungrounded group % difference
Percent difference between grounded and ungrounded groups
Using this method, the pretest difference within each group would be “0%” and both groups would start at the same baseline on the graph (see as an example for white blood cells).
White blood cells: pretest versus post-test comparisons for each group.