Sports science, distilled.
Summaries and analysis of key research papers in sports science, velocity-based training, and performance measurement.
Hamstring-to-Quadriceps Isokinetic Ratio Test: Reading Injury Risk Beyond the Sprint Score
A H:Q ratio under 0.47 or a 15% bilateral gap flags real hamstring injury risk on isokinetic testing. Here is the full protocol, norms, and interpretation.
Return-to-Sprint Force-Velocity Criteria After Hamstring Injury
Pain-free and a passed Nordic test don't prove sprint mechanics recovered. See the force-velocity protocol and cutoffs strength testing misses.
When Tester Strength Biases Handheld Dynamometer Readings
Handheld dynamometer scores shift with who holds the sensor. See why make vs. break testing hides tester-strength bias, and the fixation fix that removes it.
IMU Magnetometer Interference Indoors: Why Steel Gyms Cause Heading Drift
Steel racks and rebar bend the local magnetic field and corrupt IMU heading. Two lab studies quantify the drift and the floor-mapping fix that controls it.
Limb Symmetry Index Cutoffs After Injury: Why a 90% Pass Can Still Mean the Athlete Isn't Ready
A 90% limb symmetry index can pass even when the healthy leg got weaker too. See the absolute-value check, real cutoff table, and testing protocol.
Rising Velocity Mid-Block: Real Gain or Artifact?
Velocity climbing at the same load mid-block? A checklist for telling real strength adaptation apart from technique cleanup and plain measurement noise.
Rowing Force Curve Asymmetry: Diagnosing Left-Right Leg Drive Imbalance by Curve Shape
A clean 3% peak-force asymmetry can still hide a leg that quits early. See how a rowing force curve's shape flags leg drive imbalance a percentage misses.
Smallest Worthwhile Change: Reading Real Shifts in Athlete Tests
A 1.4cm CMJ gain can be noise or a real improvement depending on your test's typical error. Worked SWC and TE calculations coaches can copy this week.
Sprint Momentum vs. Velocity: What Actually Predicts Collision Success
Rugby and football research shows sprint momentum, not raw speed, separates starters from reserves. How to test it and train the right qualities by position.
Sprint Split Time Benchmarks: 10m and 30m Norms by Sport and Level
A 0.05s gap at 10m separates D1 corners from walk-ons. See sprint split benchmarks by sport and level, plus how to test 10m and 30m correctly.
Squash Lunge Asymmetry: What a Dominant-Diagonal Deceleration Bias on IMU Data Really Means
A clean lunge asymmetry score can hide a leg that brakes and returns slower on the same corner every time. See the IMU protocol and cutoffs that catch it.
Tethered Swim Force Test: Validity, Setup, and Interpretation
A fixed rope and load cell measure real propulsive force in the water, not a land proxy. The rig, protocol, and force ranges that actually hold up.