What is Force?
When talking biomechanics, pressure often gets confused with force and vice-versa. Pressure cannot exist without force. While they are related in this regard, the difference between the two can be boiled down to: force is the total impact of one object on another, whereas pressure is the physical quantity of force spread over an area.
Force plate technology is traditionally considered to be the “gold standard” because it is widely used in clinical research and athletic force studies. A force plate measures the Total Force (usually expressed in Newtons) applied to the surface of the platform, thus providing only the total value of a directional force. Force plates are effective at measuring ground reaction forces during walking, jumping, or other types of movement. The data from a force plate is useful, but it’s only part of a larger movement picture.
That’s where ground pressure analysis comes into play, and why understanding the science behind ground pressure is such an important complement to analyzing the entire golf or baseball swing.
What is Ground Pressure?
Ground pressure sensing technology provides enough data points to divide the plantar (bottom of foot) pressure data into multiple zones laterally and medially. With pressure analysis, you can assess isolated curves for the rearfoot, midfoot and forefoot, compare both left and right asymmetries, and pressure and temporal characteristics during all phases of the golf and baseball swing. By capturing this data, you can identify the statistics in each region of the foot, and isolate the force-time and pressure-time curves for each segment. In addition, the direction, speed, and displacement of one’s center of force/center of pressure is captured which correlates to what kind of movement the force produced.
Segmentation of the foot, together with CoP (center of pressure) progression, is probably one of the most appreciated features of ground pressure sensing technology. The ability to isolate ground reaction forces and obtain force-time curves for each foot region represents a paradigm shift in performance analysis.
From a biomechanical point of view, movement occurs dynamically over time and area, not just in one direction. Analyzing the pressure over area during movement and seeing what part of the foot interacts with the ground can dramatically increase a coach’s understanding of how an athlete’s movement is related to performance.
A New “Gold Standard”
Top golf and baseball instructors are now using pressure mats in conjunction with the data gathered from video to analyze an athletes’ full interaction with the ground through a golf or baseball swing. Ground pressure mats provide significantly more minute detail than force plates and help us “see” how all points of ground contact are interacting during movement.
Combining ground pressure technology with great coaching is resulting in measurable improvement with pros and everyday amateur athletes, and is quickly becoming the new “gold standard” coaching tool.
-By Phil Stotter, V1 Sports Director of Sports Science