Dynamic Strength Index or DSI is a concept where you aim to measure the difference between an athletes maximal strength capacity and explosive strength capacity.
A nice example would be measuring or using an isometric mid-thigh pull and a countermovement jump. The calculation is performed by dividing the peak force output in the explosive test (in this case the Counter Movement jump) by the peak force output in the maximal strength test (the Isometric mid thigh pull in this instance). A higher score would indicate the athlete is more capable at utilising their force potential during a ballistic exercise. But In contrast, the lower an athletes DSI score is potentially the less capable they are at utilising their force potential during ballistic exercises.
Having this is information is great and an interesting academic insight, however, we have to learn something meaningful or be able implement or act in a meaningful practical way too. As a rule of thumb this is how the DSI could influence programming.
- Low DSI (<0.60) – Training Emphasis Recommendation = Ballistic Strength Training / Focus on rate of force development.
- Medium DSI (0.60-0.80) – Training Emphasis Recommendation = Concurrent Training
- High DSI (>0.80) – Training Emphasis Recommendation = Maximal Strength Training
That’s todays quick explanation of Dynamics Strength Index from Vald which of course their forcedecks are perfectly designed to support. DSI is not a silver bullet, but it is an indicator of performance that we can quickly and easily use to understand or direct decision making.
Sheppard, J.M. and Chapman, D.W., An Evaluation of a Strength Qualities Assessment for the Lower Body, Journal of Australian Strength and Conditioning, 2011, 19, 14-20