Sports science, distilled.
Summaries and analysis of key research papers in sports science, velocity-based training, and performance measurement.
Curved Sprint Asymmetry: Left vs Right-Turn Gaps as an Injury Flag
A hamstring re-tears three weeks after clearing straight-line sprint tests -- it happened on a curve. Here's how to test left vs right bend sprint gaps first.
Reading the Concentric:Eccentric Velocity Ratio for Fatigue: What a Rising E:C Number Actually Means
Concentric velocity crashes late in a set while the eccentric phase barely slows -- here's what a rising C:E ratio reveals about neuromuscular fatigue.
Overground vs. Treadmill Running Speed: Why Your Numbers Never Quite Match
Your treadmill display and outdoor watch rarely agree, and it's rarely your fitness. See the belt-calibration math, two real studies, and how to fix the gap.
Sprint Hurdles Inter-Hurdle Rhythm Analysis: Diagnosing Deceleration via 3-Step Split Variance
Finish time was 0.03s off her best -- hurdle 7 alone cost twice that. Here's how to find which inter-hurdle split broke rhythm first, not just the total.
Why Flying Sprints Record a Higher Top Speed than Standing Starts
Flying sprints measure true top speed; standing starts measure acceleration. Here's the split-time math and protocol to test both correctly.
How Accurate Is Wrist Optical Heart Rate During Lifting?
Grip pressure and rep motion corrupt the PPG signal under a barbell. Here is what the accuracy studies found, and when to switch to a chest strap.
Achilles Tendon Load Tolerance: Heel-Rise Work Benchmarks for Return to Running
Symmetric strength doesn't prove the tendon can handle running's repeated load. See the heel-rise total-work protocol and symmetry cutoffs that actually do.
Asymmetry Percentage: Noise vs. Real Difference in Strength Testing
A 14% strength gap can flip to 4% on next-day retest with nothing changed. See the typical error formula and 3-session protocol that separate noise from real.
Ballistic Bench Throw Velocity Standards: What Good Actually Looks Like
A 0.3 m/s drop at the same load is real fatigue, not noise. See bench throw velocity benchmarks by load and level, plus how to test it without guessing.
Why the First Warm-Up Rep's Velocity Is Noisy and Should Be Cut From Your Load-Velocity Regression
The opening warm-up rep runs slower than rep two or three. Here is the neuromuscular reason, the data behind it, and how to fix your load-velocity line.
GPS Heat-Map Positioning Error in Team Sports: Why Roofs and Stands Distort the Map
GPS position error near roofs, stands, and floodlight towers can shift heat-map clusters by several meters. The mechanism, two validation studies, and the fix.
Grip Strength Asymmetry and Injury Monitoring: Testing Protocol, Thresholds, and Correction
A 10%+ grip gap between hands can predate elbow and wrist injuries by weeks. See the dynamometer protocol, threshold table, and retest schedule.