Hansen et al 2011, compared elite and junior rugby players by looking at their 3 rebound squat with 40kg and using the data gathered for power-time and force-time curves. Players also ran 30m sprints. In comparing speed, force-time, velocity-time and peak power, rate of force development and rate of power development it was found that most values differentiated. When one accounted for bodyweight however, only the power-time curve showed a significant difference between levels of play. This would indicate that a good indicator of elite rugby play would be the power-time curve of a loaded jump squat. Having the highest strength to weight ratio as possible while being as fast as possible seem to be what the data suggests a good rugby player needs.

Similarly, Chelly et al 2010 compared junior level soccer players leg power. A squat jump, counter-movement jump, muscle volume, 5m sprint and max squat were tested. They found correlations among sprinting speed and the height achieved by the counter movement jump and the max squat. So the faster soccer players jump higher and are stronger.
Want to play elite sports? Get bigger, stronger and run faster.