Ani Henriksen and Dr. Sarah Ridge, Biomechanics
Introduction
Running is a popular form of exercise. With high incidence of injury, runners are always looking for the next cure to stay injury free. Many webpages offer conflicting advice about shoes and foot strike. Although recommendations vary, barefoot running and use of minimalist shoes has increased. With the change in footwear, many runners have reported injuries from improper technique and repetitive loading. With the use of current technology we analyzed movements of the foot ignored by other studies. This project analyzed foot strike movement in the frontal plane to help us better understand the ideal foot strike technique for running barefoot or with minimalist shoes.
Methodology
Thirty-six subjects who gradually transitioned to Vibram FiveFinger shoes over a 10 week period were analyzed for foot strike angles in the sagittal plane and frontal plane. Foot strike angles were first graphed for correlation between frontal and sagittal angles. Second, angles were compared between successfully transitioned runners and partially transitioned runners. To process data, computer models were assembled using two different programs, Vicon and Visual 3D. Vicon was the motion tracking software used to collect running trials. Once trials were labeled in Vicon, they were moved to Visual 3D. Visual 3D was used to construct 3D skeletal models which were used to calculate frontal and sagittal plane angles at foot strike.
Results
Frontal and sagittal angles were taken from all subjects and graphed to find correlation between sagittal and frontal angles. Each subject had 9 trials before and after transitioning: 3 in the barefoot condition, 3 while wearing Vibram 5 fingered shoes, and 3 while shod with regular running shoes. Averages were taken from each condition and were graphed before and after transitioning to Vibram shoes. Figure 1 shows barefoot transition graphs, figure 2 shows Vibram graphs and figure 3 shows shod graphs. Sagittal angles are on the X axis, Frontal angles are on the Y axis. After graphing, there appeared to be no correlation between angles.
Discussion
Sagittal angles, as observed by other researchers, show a trend of greater sagittal angles for barefoot and Vibram trials while having smaller sagittal angles for shod trials. Once combined with frontal angles, however, there appears to be no correlation in overall foot strike. Frontal angles are difficult to measure and other studies should be conducted for more precise measurements.
Conclusion
There appears to be no correlation between frontal and sagittal angles in this study. However, other data collection methods should be used to better analyze frontal angles to determine if frontal angles are affected during transition to barefoot or Vibram conditions and if there is correlation to injury.