NDSU student Sarah Hilgers and Bryan Christensen, associate professor of health, nutrition and exercise science, presented "The Effects of Strength, Power, and Genu Valgum Following a Five Week Training Program With Whole Body Vibration" at the International Society of Biomechanics in Sports conference in Limerick, Ireland. At the same conference, Josh Aman and Christensen presented "Effects of Static Stretching, PNF Stretching, and Dynamic Warm-up on Maximum Power Output and Fatigue."
Hilgers is a master's student who also has started pursing a doctorate at NDSU. Aman is a former undergraduate and master's student and is currently a doctoral student in biomechanics at the University of Minnesota.
Hilgers and Christensen examined the effects on strength, power and genu valgum angle following a five-week resistance training program either with or without whole-body vibration. One group did resistance training while standing on a vibration platform. A second group did the same resistance training program on the gym floor without vibration. Pre- and post-test evaluation included maximum countermovement vertical jump, standing long jump, medicine ball toss, 1RM of both chest press and leg press and genu valgum measured at maximum genu valgum angle at knee bend following a land and load maneuver.
The results of this study indicated greater improvement in both the countermovement vertical jump and leg press following the vibration training. However, the resistance training group without vibration displayed greater improvement in standing long jump, medicine ball toss and chest press. One subject in the resistance training group and two subjects in the resistance training group with vibration exhibited genu valgum in one of their legs. All three subjects improved at the post-test.
Aman and Christensen sought to determine the effects of static stretching, PNF stretching and dynamic warm-up on maximum power output and fatigue. The participants performed a vertical jump test at three minutes and 20 minutes post-treatment for all treatments until voluntary fatigue. Participants performed a standard protocol including one of the stretching and warm-up treatments followed by two repeated, counter-movement, vertical jump tests.
No statistically significant differences were found. The dynamic warm-up group was found to have 10 percent higher average power output compared to the control group. Up to a six second difference was found in fatigue between the treatments and the control group.
