Athlete tools · Free · No account
Seven tools for athletes who want a number instead of an opinion: jump and sprint trackers, a power calculator, a signal-or-noise check, the three-week Springbak® Challenge and a scored trunk-rotation test. Everything runs in your browser, saves to this device, and exports to a one-click PDF you can hand a coach.
Trackers
One entry per session, best attempt only. The chart draws itself once you have two data points, and your personal best sits at the top of each card.
inches · Higher is better
seconds · Lower is better
Calculators
Every formula is named and cited on the card so a coach can check the math. Nothing leaves your browser.
Calculator 01
Turn a vertical jump into peak mechanical power, so a half-inch gain reads as watts instead of a shrug.
Enter a jump height and body weight to see your peak power.
Sayers countermovement-jump equation: peak power (W) = 51.9 × jump (cm) + 48.9 × body mass (kg) − 2007. An estimate from a field test, not a force-plate reading.
Calculator 02
Convert any timed run into velocity you can compare across distances, surfaces and seasons.
Enter a distance and a time to see speed in mph and m/s.
Average velocity over the whole run: distance ÷ time. Hand timing runs roughly 0.2 s faster than an electronic gate, so compare hand to hand only.
Calculator 03
Compare your baseline best against your re-test best and find out whether the change survives measurement error.
Enter both numbers to see whether the change is bigger than the error bar.
Noise thresholds: 0.5 in on a jump, 0.05 s on a hand-timed sprint. Compare bests, not averages, and keep surface and shoes identical.
Protocol · Three weeks
The whole point of a test is that one thing changed. Run it exactly like this and the trackers above will tell you what the insole did.
01
Three sessions on the same surface in the same shoes. Best of three attempts each session, logged here.
02
Install your Springbak® Springsoles without changing anything else about the session. Try the Springsole without trimming first. If the factory liner is removable, remove it and place the Springsole underneath it. If the liner is lightly glued, gently pull to see whether it releases cleanly; if it does, place the Springsole underneath it. If the liner begins to tear, stretch, deform, or resist removal, stop and leave it in place. Put the Springsole on top instead. Never force out a firmly bonded or stitched liner.
03
Same surface, same shoes, same time of day, same warm-up. Log every attempt so the trend line does the arguing.
04
Compare bests, not averages, and run the numbers through the signal-or-noise check. A tenth is real; a hundredth is noise.
Challenge Two
Basketball, volleyball, golf, baseball, track and field and strength training all depend on more than straight-line speed. Core mobility and body control matter just as much, and rotation is the cheapest way to test them — no tape measure, no timing gate.
Do not force the movement. The purpose is to compare how your body feels and moves under the same conditions, so keep the shoes, surface, stance and technique identical on both attempts.
Take the test, then rate the second attempt against the first to get your Springbak® Challenge score.
Turn. Control. Compare. Same athlete, same shoes, same challenge.
Patents & force plate testing
Balance & stability
2×+
force required to displace a subject standing on Springsoles
It took more than twice the force to push subjects off the force plate while they stood on Springsoles. The reviewing investigator concluded there is a significant strength and stability increase for individuals using Springsoles under laboratory conditions.
Sponsored by the Department of Gerontology, Brigham Young University
Stride analysis
Fewer strides
over the same distance vs. placebo inserts
Athletes wearing Springsoles took fewer strides over the same distance than with placebo inserts — the pattern you expect from increased stride length at the same effort.
University of Southern California
Patent family
4 patents
U.S. patents covering the spring-plate insole system
In force-plate testing, subjects standing on Springbak® Springsoles showed more than twice the overall resistance to being pushed from their position.
In plain English: they were harder to move. They could hold their ground better against a sideways push—exactly the kind of stability athletes need when planting, cutting, jumping, landing, and absorbing contact.
Springbak® gives the foot a more stable, responsive platform to work from inside the shoe.
Results are from the force-plate testing described in U.S. Patent No. 6,589,630 B1. Individual results vary.
Tool guides · Method, math and questions
What each tool measures, the equation behind it, how to run the test so the number holds up, reference ranges to compare against, and the questions athletes ask most.
Guide 01 · Vertical jump tracker
A vertical jump only means something when it is measured the same way twice. This tracker keeps one entry per session — your best attempt — with a note for surface, footwear and session type, then draws the trend line so a training block reads as a slope instead of a story.
Log a baseline week before you change shoes, insoles or programming. Once two entries exist, the chart appears and your personal best pins to the top of the card. Nothing is uploaded: entries live in this browser on this device.
The math
Jump height = highest marked reach − standing reach. Keep three attempts per session and record the best, never the average.
How to run it
Questions
Chalk your fingertips, take a countermovement jump beside a wall from a standstill and mark the highest point, then subtract your standing reach. Three attempts, best one counts, and repeat the identical setup every re-test.
Every one to three weeks. Daily testing mostly measures fatigue and sleep; a one to three week gap is long enough for a real adaptation to show up above the half-inch error bar.
No. Entries are stored in your browser's local storage on the device you used, so there is no account, no upload and no sync. Download the PDF summary if you want a copy to send to a coach.
Guide 02 · Sprint time tracker
Sprint times move for reasons that have nothing to do with fitness: a following wind, a tailored start, a friend with a slow thumb. Logging every timed run with the surface and start method noted turns a pile of numbers into a trend you can defend.
Keep hand times and electronic gate times in separate mental buckets — hand timing typically reads about 0.2 seconds faster because the thumb starts late. Compare like with like, then run the two bests through the signal-or-noise check.
The math
Trend is judged on the best time per session. Treat 0.05 s as the noise floor for hand timing over 10–40 yards.
How to run it
Questions
A hand timer starts the watch on movement it sees late and stops it on anticipation, which is worth roughly two tenths of a second compared with an electronic gate. Track hand times against hand times only.
Two or three maximal efforts with full recovery. Beyond that, fatigue makes each run slower and the session stops measuring speed.
Guide 03 · Jump power calculator
Two athletes can jump the same height and produce very different amounts of power, because power depends on the mass being launched. The Sayers equation estimates peak mechanical power from countermovement-jump height and body mass, which is why a heavier athlete who jumps 26 inches can out-power a lighter athlete at 28.
Use watts to judge training decisions across a season: if body mass climbs and jump height holds, power went up even though the tape measure says nothing changed. Divide by mass for watts per kilogram when you want to compare athletes of different sizes.
The math
Sayers peak power (W) = 51.9 × jump height (cm) + 48.9 × body mass (kg) − 2007. Inches × 2.54 = cm; pounds × 0.453592 = kg.
How to run it
Questions
Peak power in watts equals 51.9 times jump height in centimetres plus 48.9 times body mass in kilograms minus 2007. It was published by Sayers and colleagues as a field estimate of peak mechanical power from a countermovement jump.
No. It is a regression estimate from two field measurements, so it carries error of a few hundred watts. It is reliable for tracking one athlete over time with the same measurement method, which is what most training decisions need.
Watts for your own progress across a block, watts per kilogram when comparing athletes of different body masses or when body mass changed between tests.
Guide 04 · Sprint speed calculator
A 4.85-second 40 and a 11.2-second 100 metres are hard to compare until both become velocity. This calculator converts a distance and a time into average speed in miles per hour, metres per second and kilometres per hour, plus the average time per 10 metres.
Remember it reports average velocity over the whole run, including the standing start. Peak speed in the back half of a 40 is meaningfully higher than the average, which is why flying-10 splits are the better gauge of top speed.
The math
Average velocity = distance ÷ time. Yards × 0.9144 = metres; m/s × 2.23694 = mph; m/s × 3.6 = km/h.
How to run it
Questions
Forty yards is 36.58 metres, so 4.5 seconds is an average of 8.13 m/s — about 18.2 mph. Peak speed during that run is higher, because the average includes the standing start.
Average speed over the distance you entered. To estimate top speed, time a flying 10 with a running start and convert that split instead.
Guide 05 · Signal or noise check
Every test has an error bar. A quarter-inch on a jump or two hundredths on a hand-timed sprint is inside the range you would get by re-measuring the same athlete on the same day, so calling it progress is a coin flip dressed as a result.
This check compares your baseline best against your re-test best, converts the change to a percentage, and tells you whether it clears the noise floor. It is deliberately conservative — a result that survives it is one you can bring to a coach.
The math
Change = re-test best − baseline best (reversed for sprint time, where lower is better). Verdict: |change| below the noise floor is noise. Noise floor: 0.5 in on a jump, 0.05 s on a hand-timed sprint.
How to run it
Questions
Treat half an inch as the threshold for a wall-mark or Vertec test. Smaller changes fall inside typical day-to-day measurement variability, so they cannot be separated from error without repeated trials.
Hand timing carries roughly five hundredths of a second of error. If your improvement is smaller than that, the stopwatch could have produced it on its own — run the test again and look for the change to repeat.
Guide 06 · Springbak® Challenge protocol
The point of a test is that one thing changed. The Springbak® Challenge holds surface, footwear, warm-up and time of day constant for three weeks and changes exactly one variable: Springsoles fitted according to the shoe's liner type.
Week one is a baseline. Weeks two and three are re-tests. Judge the result on bests, run it through the signal-or-noise check, and the trackers on this page will have done the arguing for you.
The math
Baseline week (3 sessions) → install Springsoles → re-test weeks 2 and 3 → compare bests against the noise floor.
How to run it
Questions
Three weeks: one baseline week, then two weeks of re-tests with Springsoles fitted according to the shoe's liner type.
Remove a factory liner only when it is removable or releases cleanly with a gentle, steady pull. Stop if it starts to tear, stretch or deform. Never force out a firmly bonded or stitched liner; leave it in place and put the Springsole on top.
Guide 07 · Trunk and core twist test
Rotational control is what turns ground force into bat speed, club-head speed and a stable landing. This scored test walks through a seated and standing twist sequence, records how far you rotate and how well you hold position, and returns a score you can re-test against.
It is the same idea behind the force-plate work on Springsoles: the more force it takes to displace a standing subject, the more stable the base they are rotating from. Score it before you change anything, then again three weeks later.
The math
Score combines rotation range and hold quality across both sides; asymmetry between sides is flagged separately.
How to run it
Questions
It shows how much rotation you can control from a fixed base and whether your two sides match. Rotational sports lose power and load one side harder when range or control is asymmetric.
Yes — the surface under your foot sets the base you rotate from, which is why the protocol asks you to keep shoes and floor identical between tests. Force-plate testing on Springsoles showed more than twice the force was required to displace a standing subject.
Questions
No. Every tracker and calculator runs in your browser and your entries are stored on the device you are using, so nothing is uploaded and nothing is tied to an email address.
Chalk your fingertips, jump from a standstill next to a wall and mark the highest point, then subtract your standing reach. Do three attempts, keep the best, and repeat the exact same setup every time you re-test.
Treat half an inch on a jump and five hundredths of a second on a hand-timed sprint as the error bar. The signal-or-noise calculator on this page compares your baseline best against your re-test best and tells you which side of that line you landed on.
Three weeks: a baseline week, then two weeks of re-tests with the Springsoles fitted according to the shoe's liner type. Keep the surface, footwear and warm-up identical so the Springsole is the only thing that changed.
Study summaries describe laboratory evaluations of Springbak® Springsoles conducted with the named investigators. Individual results vary. Springbak® Springsoles are performance footwear components and are not a medical device, and no claim is made to diagnose, treat or prevent any condition.
The receipts
4
U.S. patents
Nos. 5,554,694, 5,695,850, 6,120,880, 6,589,630 B1 — performance-enhancing athletic shoe components and methods.
Read the patent family2×+
Force to displace
Force plate testing at the Weber State University Human Performance Laboratory: more than twice the force was needed to push subjects off balance on Springsoles.
See the force plate dataBalance
& stability study
Evaluated with Dr. Michael Yessis, Dr. Robert Wiswell and Howard Gray, PhD — stability and functional strength, measured rather than claimed.
Read the study