String Performance Report Maker
Instructions:
1. Click fields you want displayed (only 10 allowed).
2. Choose filter conditions to limit results.
3. Select sort ordering to arrange results into meaningful groups and ranking.
4. Keep it simple — Focus results by choosing fewer display fields or limiting searches with the drop down menus.
5. Click here to see testing procedure
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To
Display		 Performance Measurement Instructions and Information
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 Brand
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 Choose String or Strings (see at right)
 To select/deselect multiple strings:
1. Windows: hold down control key while clicking each string.
2. Mac: hold down command key while clicking each string.

If you choose 'All Strings', make sure you haven't also chosen individual strings.

Hint: To select all strings in a brand (or any set of successive strings), click first string and then hold down shift key while clicking last one in the range.
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 Choose Reference Tension
 Very helpful since results depend heavily on this. However you can choose a tension for search purposes and not display it.
What is it? These are the starting tensions the test strings were pulled to. Each string performs relatively better at different tensions compared to other strings due to the differing forces created by stringbed stiffness.
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 Choose Swing Speed (fast, medium, slow)
 Very helpful since results depend heavily on this. However you can choose a swing speed for search purposes and not display it.
What is it? These are the speeds of the test hammer impacting the string, calibrated to simulate actual fast, medium and slow swings. Strings behave differently depending on relative impact speed with the ball due to the differing forces created.
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 Choose Prestretched String Results
 Hint: If you choose 'prestretch and no prestretch', you will also want to display that fact to differentiate the performance results.
What is it? Prestretching involves preinstall-loading of the string for a time at a tension as high and higher than the desired tension. This 'takes stretch out of the string', making it stiffer.
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 Choose String Material
 Hint: If you choose other than 'All', make sure 'All Strings' is chosen in the string choice dropdown menu.
Some material categories might not have any strings. The most represenative are are gut, nylon, polyester, nylon/polyurethane, nylon/polyester, and polyolefin.
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 Gauge nominal What is it? Nominal gauge is that listed on the package.
Actual gauge is the measured gauge of the string we tested.
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 Gauge actual
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 Static Stretch at 40 lbs What is it? Immediately after pulling the test string to its reference tension, the elongation that occurred during the pull was measured. This is presented both as the actual elongation in mm and the percent elongation of the length of the pre-tensioned string (330 mm). Static elongation is of interest to stringers for determining string lengths but does not have much relevance to hitting a ball. That is dynamic stiffness and is listed below ('stiffness'). Measurements were not taken at 40 and 51 lbs for some earlier tests.
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 Static Stretch at 51 lbs
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 Static Stretch at 62 lbs
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 Actual tension What is it? During actual play and in our testing, strings lose tension with every second and every impact. This displays the actual tension in the test string at the moment of test impact.
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 Impact Tension Change (lbs) What is it? During impact the string stretches and therefore rises in tension. The amount of change will depend mostly on string material, tension, and swing speed.
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 Impact Duration (ms) What is it? This is the duration of the test hammer on the string. It is about 6 times longer than a normal tennis hit but the relative relation between strings will be the same.
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 Impact Deflection (in) What is it? The amount the string deflects perpendicular to the string plane.
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 Peak Tension (lbs) What is it? As the string stretches during impact, the tension continually increases to a peak, and then decreases back close to (but less than) its starting tension.
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 Peak Force (lbs) What is it? Impact force depends on string material, tension, and swing speed. This is the force on one string. The force on the racquet during impact might be 5-10 times higher (depending on how many strings are affected).
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 Stiffness (lbs/in) What is it? This is the key measurement. Most others depend on this. Stiffness is measured dynamically during the impact. The measurement indicates the force necessary to stretch the string 1 inch during impact.
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 Static Tension Loss (lbs) What is it? Sixty seconds was waited after pulling to reference tension and before the first stabilization impact. This is the tension lost during that time.
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 Stabilization Tension Loss (lbs) What is it? Each string was hit 20 times at high speed to 'stabilize' it before any test impact was conducted. This indicates the tension lost during those hits.
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 Impact Tension Loss (lbs) What is it? This is the tension lost during the test impact.

Note: some strings (at lower speed impacts) actually are at higher tension after the impact than before ('tension losses' referenced as negative numbers in the impact loss column)
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 Total Tension Loss (lbs) What is it? Total tension lost during the test, including the minute wait after tensioning, the 20 high speed hits to stabilize tensions, and the actual test impacts.

Note: Total tension loss will always be a little less or more than the sum of these measured loses due to increases and decreases inbetween testing activities.
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 Energy Return (percent) What is it? The percent of energy returned to the impact hammer by the string after impact compared to the hammer energy before impact.
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Sort Order 5 		Hint: Sorting is key to organizing your search into understandable groupings. For many searches that include 'All', sorts using 'Reference Tension' and 'Swing Speed' will be very helpful for viewing trends.

All sorts are in ascending order except energy return which is in descending order.

You can choose any sort fields in any order. Sort prioritizes from top to bottom.

Unfortunately, for now, the following fields cannot be sorted on: static, stabilization, and impact tension losses, actual gauge, and the elongation fields.