Principal Investigator: Yael Vodovotz
SUMMARY
Participants will begin the study by consuming a serving (7 soy pretzel bites) of the NSP after exercise, three times over the course of a week. During this time period the subjects will also be introduced to the exercise circuit and will perform the circuit twice throughout the course of a week. This will serve as the familiarization phase of the study. Assuming that most of the participants are not regular consumers of soy products and are not familiar with the specific exercise circuit utilized during the study, it is necessary to provide this period to eliminate the possibility that the effects of the study may be attributed to a reaction to soy (an unfamiliar product) and/or learning the correct exercise protocol. It will also ensure proper technique and minimize likelihood of injuries.
Following the familiarization phase, subjects will undergo a 2-week washout period. During this 2-week period, subjects will follow a legume-free diet (free from soy, tofu and peanuts) in an effort to remove any existing isoflavones that may interfere with the study results. A complete list of foods to avoid can be found in Appendix H. Participants will be instructed to include a log of any these foods consumed during this time period. During the washout period, each participant will choose three days representative of their diet during the 2-week period and fill out a 3-day diet record. The diet record will be analyzed using an Analysis of Variance (ANOVA) to rule out effects the diet may have on the results of the clinical trial and will also help verify adherence to the legume-free regimen. Participants found to have not adhered to the guidelines may have their data excluded from the study. A registered dietician will also analyze the diet records to ensure that none of the food consumed will interfere with the isoflavone analysis. Twenty-four hours prior to the experiment and twenty-four hours after, all subjects will record their exact diet and forgo all forms of physical activity (including sex, weight training, cardio, sports, etc.) with the exception of the assigned exercise circuit. The exact diet will be followed for the second part of the study to ensure consistency. After the washout period is complete, participants will complete Part 1 of the study. The trial will begin by taking baseline measurements of the subjects to use as comparison for post exercise and product consumption. The baseline measurements will include initial maximum strength which will be tested using a 1RM ,baseline soreness using a visual analog scale and range of motion of both the knee and shoulder joints using a goniometer – an instrument that tests the angle of joints. Participant’s 1RM will be determined in the squat exercise 1 week prior to Part 1 of the study. This will be used to determine the amount of weight that will be used during the exercise circuit as a percent of their 1 rep maximum. Additionally, various blood biomarkers of muscle damage (myoglobin and creatine kinase) and inflammation (total antioxidant status, malondialdehyde and myeloperoxidase) will be assessed. Participants will also be instructed to collect urine samples prior to pretzel consumption and again 24 hours after consumption to test for the presence of isoflavones.
The participants will subsequently undergo a regimented squat protocol on The Smith Machine which would have been introduced during the familiarization phase mentioned earlier in the study. This circuit will last approximately 15 minutes and is designed to induce muscle damage. Prior to performing the squat protocol, the athletes will consume approximately ½ serving of the soy or wheat pretzels (4 pieces). Next, participants will perform 6 sets of 10 repetitions at 70% of their 1RM. Due to the fact that the training level will vary between subjects, we chose 70% 1RM as opposed to the maximum 75% at 10 reps, to avoid issues with completion. After completion of the exercises, the participant will immediately consume the remaining 4 pretzel bites. Next, the soreness and blood measurements will be repeated to assess the immediate effect
of exercise on muscle damage and inflammation. The subjects will repeat the same measurements at 6 hours, 24 hours and 48 hours to determine the impact of the soy soft pretzel compared to the wheat pretzel control. After the 48- hour period, subjects will complete a questionnaire, evaluating the degree of liking, acceptability and satiety of the product following exercise.
After the completion of Part 1, subjects will undergo another identical washout period. They will then cross over to the product they did not consume in Part 1. An identical exercise regimen will be implemented in Part 2 and another identical questionnaire will be completed and compared to their survey from Part 1 of the study.