November 7, 2024
Keio University
S-CADE Inc.
"If you could measure just one thing to objectively evaluate sports performance and condition,
what would you measure?"
A research team led by Associate Professor Takataka Inami of the Keio University Institute of Physical Education (and a committee member of the Graduate School of Health Management) has developed a method to calculate jump height using a smartphone based on the displacement of segments that do not affect jump height.
To accurately calculate jump height, there is a highly reliable method called the "force-impulse method," which uses a special device called a force plate. While this method is extremely accurate, it has disadvantages: the equipment is large and difficult to transport (measurements are typically taken in a laboratory), and its use is limited to those with specialized knowledge for handling it. There is also the "flight time method," which calculates height based on the time spent in the air during a jump. This method has the advantage of being easily measurable by anyone using simple devices like lightweight mats. However, previous studies have pointed out that it can overestimate jump height by up to 10 cm compared to the force-impulse method.
The research team has now successfully resolved the issues with the flight time method, enabling jump height measurement with an accuracy nearly equivalent to the force-impulse method. This technology has been implemented in the "JumpEye" app, developed by S-CADE Inc., a joint research venture company. The app uses a smartphone's camera to record the height of the greater trochanter at takeoff as a horizontal line on the image. It then calculates the jump height from the time it takes for the greater trochanter to pass that horizontal line again after the jump (the modified flight time method).
Jump height is beginning to be recommended as an evaluation method that sensitively captures sports performance and condition. This research is expected to enable high-precision measurements in the field of competitive sports, leading to a more accurate visualization of athletes' performance and condition.
The results of this research were published in the *International Journal of Sports Physiology and Performance* on November 5, 2024.
Please see below for the full press release.