Eccentric Utilization Ratio and Rate of Force Development Relationships [Article Review]
- Whistle Performance
- Mar 16
- 3 min read
This exploratory study investigates whether the eccentric utilization ratio (EUR)—a common metric comparing countermovement jumps to squat jumps—is actually a reliable indicator of superior athletic ability. By analyzing data from over 300 athletes and students, researchers discovered a negative correlation between a high EUR and the rate of force development (RFD) during squat jumps. These results suggest that a high ratio may stems from a decreased ability to generate explosive force quickly rather than exceptional power. Consequently, the authors argue that the traditional assumption of a high EUR representing elite physical readiness is flawed. This evidence encourages sports practitioners to reconsider how they use jump ratios to evaluate athletic performance and muscle mechanics.
Rethinking the Eccentric Utilization Ratio: Does a High EUR Actually Mean Poor Force Development?
For years, sport performance coaches have used the Eccentric Utilization Ratio (EUR)—the ratio between a countermovement jump (CMJ) and a squat jump (SJ)—as a go-to metric. The traditional thought process was simple: a higher EUR indicates an athlete's superior ability to effectively utilize elastic energy and the stretch-shortening cycle. However, a recent exploratory study titled "Is larger eccentric utilization ratio associated with poorer rate of force development in squat jump?" flips this conventional wisdom on its head.
Here is a breakdown of why this study was conducted, what it found, and what it means for your coaching practice.
Why the Study Was Done
The study was initiated to challenge the prevailing assumption that a high EUR is always a marker of superior athletic performance. Recent theories have suggested that a large EUR might not actually result from a fantastic CMJ, but rather from a remarkably poor SJ performance. Specifically, researchers hypothesized that athletes with a poor rate of force development (RFD)—the ability to quickly generate force—or increased muscle slack would struggle with the static start of a squat jump. Because they benefit more from the "pre-loading" of a countermovement, their EUR appears artificially high. The study aimed to explicitly investigate if a higher EUR actually correlates with a poorer ability to rapidly develop force in the squat jump.
Results of the Study
Researchers analyzed data from 313 participants (209 men, 104 women), including basketball players, soccer players, long-distance runners, and physical education students. They measured EUR using three variables—jump height, peak force, and peak power—and compared these against the athletes' rate of force development during the propulsive phase of the squat jump (SJ RFD).
The results showed a small to moderate, but statistically significant, negative correlation between EUR (when based on peak force or power) and the rate of force development in a squat jump. Ultimately, the data suggested that as an athlete's EUR increases, their ability to rapidly develop force from a static position decreases.
4 Key Findings
Peak Force EUR negatively correlates with RFD: There was a statistically significant negative correlation (r = -.41) between EUR based on peak force and SJ RFD across the entire sample.
Peak Power EUR also negatively correlates with RFD: Similarly, EUR based on peak power demonstrated a significant negative correlation (r = -.27) with SJ RFD.
Jump Height EUR showed no significant correlation: Interestingly, when EUR was calculated the traditional way—using just jump height—it did not show a statistically significant correlation with SJ RFD. The researchers noted that factors like joint coordination and postural balance might influence jump height too much, masking the correlation.
The trend persists across multiple sports: The negative correlation between peak force EUR and rapid force development wasn't isolated; it was found across different subgroups, including male basketball players, male soccer players, and female physical education students.
Conclusion: Takeaways for Sport Performance Coaches
Do not blindly celebrate a high EUR as a sign of superior physical readiness.
The biggest takeaway for coaches is that a high EUR might actually be highlighting a mechanical deficiency. Instead of indicating great stretch-shortening cycle efficiency, a high EUR may be a red flag that your athlete has a poor rate of force development or too much "muscle slack" when starting from a static position. They are relying heavily on the countermovement just to pre-tense their muscles because they struggle to generate force rapidly without it.
Moving forward, coaches should reconsider using EUR as a straightforward performance marker. If you see a high EUR in your athletes, it is worth digging deeper into their force-time curves and prioritizing training that improves rapid, static force generation and tendon stiffness, rather than just assuming their elastic qualities are optimal.
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