AlecG
Semi-Pro
Correction: it should say "power change" in the title instead of "power loss", since power likely increases with reduced string tension over time.
I was going over the String Performance Database at the Tennis Warehouse University (https://twu.tennis-warehouse.com/learning_center/reporter2.php) and I thought of a few suggestions for what could be added, one of which would be very easy (but the other two would be more useful).
1) Power Estimate: The easy thing would be to calculate a power estimation, which I think could be approximated by Energy Return divided by Stiffness & perhaps then multiplied by 100 for ease of reading, so Power Estimate = 100*EnergyReturn/Stiffness. This Power Estimate would vary from PE = 130 for Pacific Prime Gut Orange Bull 16 @ 51 lbs, and PE = 97 for Ashaway Dynamite Soft 18 @ 40 lbs, to PE = 29 for Luxilon 4G S 15 @ 62 lbs (or even less if Kevlar is added).
The first obvious objection to this is that it's not that different to the inverse of the stiffness, since energy return doesn't vary a huge amount between strings & tensions, but it'd be a slight improvement on that inverse & basically just as easy to add, and I think good enough for a rough comparison between strings & tensions. It's also necessary for the implementation of suggestion number 3.
Another objection would be that "Power" can be a bit misleading here (even though it's standard to use this term) and perhaps it should be called something like "Rebound Potential" instead. Either would be fine in my opinion.
2) Stiffness Loss (%): More useful, but much harder to add if it hasn't already been measured ie the data isn't sitting there already, would be to add "Stiffness Loss (%)" rather than just "Tension Loss (%)". Since the loss of stiffness with loss of tension is non-linear & also varies greatly by string type, stiffness loss is a better proxy for power loss which is fundamentally what we care about, which brings me to...
3) Power Change Estimate (%) [or Rebound Change Estimate (%)]: If the data for stiffness *after* tension loss already exists or could be measured in the future, this could allow the calculation of a Power Estimate not only before but also after tension loss, which would would allow the calculation of a Power Change Estimate. Fundamentally, this is the main reason we care about tension maintenance, but unlike "tension loss" a Power Change Estimate would account for the non-linear changes in both stiffness & energy return & the variance in these non-linear curves by string type, and it it would require is the data from measurements of stiffness *after* tension loss along with the published date and the calculations outlined above.
If you know anyone who works at Tennis Warehouse University, I'd appreciate if you could pass on these suggestions.
I was going over the String Performance Database at the Tennis Warehouse University (https://twu.tennis-warehouse.com/learning_center/reporter2.php) and I thought of a few suggestions for what could be added, one of which would be very easy (but the other two would be more useful).
1) Power Estimate: The easy thing would be to calculate a power estimation, which I think could be approximated by Energy Return divided by Stiffness & perhaps then multiplied by 100 for ease of reading, so Power Estimate = 100*EnergyReturn/Stiffness. This Power Estimate would vary from PE = 130 for Pacific Prime Gut Orange Bull 16 @ 51 lbs, and PE = 97 for Ashaway Dynamite Soft 18 @ 40 lbs, to PE = 29 for Luxilon 4G S 15 @ 62 lbs (or even less if Kevlar is added).
The first obvious objection to this is that it's not that different to the inverse of the stiffness, since energy return doesn't vary a huge amount between strings & tensions, but it'd be a slight improvement on that inverse & basically just as easy to add, and I think good enough for a rough comparison between strings & tensions. It's also necessary for the implementation of suggestion number 3.
Another objection would be that "Power" can be a bit misleading here (even though it's standard to use this term) and perhaps it should be called something like "Rebound Potential" instead. Either would be fine in my opinion.
2) Stiffness Loss (%): More useful, but much harder to add if it hasn't already been measured ie the data isn't sitting there already, would be to add "Stiffness Loss (%)" rather than just "Tension Loss (%)". Since the loss of stiffness with loss of tension is non-linear & also varies greatly by string type, stiffness loss is a better proxy for power loss which is fundamentally what we care about, which brings me to...
3) Power Change Estimate (%) [or Rebound Change Estimate (%)]: If the data for stiffness *after* tension loss already exists or could be measured in the future, this could allow the calculation of a Power Estimate not only before but also after tension loss, which would would allow the calculation of a Power Change Estimate. Fundamentally, this is the main reason we care about tension maintenance, but unlike "tension loss" a Power Change Estimate would account for the non-linear changes in both stiffness & energy return & the variance in these non-linear curves by string type, and it it would require is the data from measurements of stiffness *after* tension loss along with the published date and the calculations outlined above.
If you know anyone who works at Tennis Warehouse University, I'd appreciate if you could pass on these suggestions.
Last edited:
