Developed by Dr. Richard P. McCormick, the Dynamic Strength Index (DSI) is a performance testing ratio that helps you understand how effectively your athletes convert their maximum strength into explosive power and can provide insight into where the potential for training benefits may come from for the people you work with. It can also be a useful metric to simplify the profiling of an athlete and engage coaches and parents a like with working with younger clientele.
Here’s how you can use force plates to measure and apply the DSI to your training programs.
Test Selection
The DSI looks at the ratio of performance between a maximum strength and ballistic strength movement. Using AxIT this is conducted by performing an Isometric Mid Thigh Pull (IMTP) for maximum strength and force production, and a Counter Movement Jump (CMJ) for rapid ballistic output.
The great thing about these tests is that they are safe for junior athletes to perform and can be done rapidly and even portably when using AxITs portable IsoBase accessory allowing them to be performed at a sports club or event.
Interpreting Results
The DSI is calculated using the following formula.
Fortunately for AxIT users, there is no need to get the calculator out as AxITs software will automatically calculate this for you and track it over time or allow for instant generation in a report.
- Low DSI (<0.60): Indicates that the athlete may struggle with explosive strength or have a strength bias as they produce far greater force on a maximum strength movement than on a ballistic movement. This could refer to an athlete such as a large rugby forward who is very strong but not particularly fast. Recommendation: Focus on ballistic strength training, such as plyometrics and speed drills, to enhance explosive power and improve ballisitc force production.
- Moderate DSI (0.60-0.80): Suggests a balance between maximum strength and explosive power. This athlete expresses their athleticism well. Recommendation: Implement concurrent training, combining elements of both strength and explosive power training to address both areas effectively to maintain and develop both qualities equally. Further analysis against normative data may be needed to decide whether the athlete is balanced but deficient.
- High DSI (>0.80): Shows that the athlete is efficient in converting strength into explosive power or has a ballistic force bias as they produce far greater relative force on the ballistic movement than the strength movement. This could describe an athlete such as a tall basketball player who excels in jumping but may not be strong in weightlifting.Recommendation: Emphasize maximal strength training to further develop strength capabilities and maintain performance levels.
Conclusion
The Dynamic Strength Index (DSI) offers a powerful and simple way to assess how effectively your athletes convert strength into explosive power, providing valuable insights to optimize their training. Whether working with junior athletes or seasoned professionals, using force plates like AxIT to measure DSI can help you create more personalized and effective programs. By tracking this ratio over time, coaches and parents can better understand an athlete’s needs and guide their development with greater precision.
If you’d like to learn more about integrating the DSI and AxIT force plates into your training programs, reach out to the team at www.strengthbynumbers.com. We’re here to support you in maximizing your athletes’ performance potential!