Running dynamics have a reputation for being the numbers nobody uses, and that is mostly because they get read as a scorecard. Used as a fatigue signal instead, they earn their place.
What Coachbox reads
Vertical oscillation, vertical ratio, ground contact time, stride length and cadence, all pulled from the file your watch records. Coachbox stores the session and lap averages alongside pace and heart rate.
A run recorded on an Apple Watch and a run recorded on a Garmin land on the same scale, so you can compare an athlete’s numbers across devices without second-guessing the units.
Use them for change, not for grading
There is no ideal ground contact time. Athletes are built differently, and the form that looks wasteful in a table is often the cheapest one for that body. Comparing two athletes against each other usually produces a wrong conclusion.
Comparing an athlete against themselves is a different matter. Ground contact time creeping up through a long run marks where fatigue started to bite. Cadence collapsing in the last third of a marathon-pace session tells you the session was too long or too fast. That is coaching information.
The cadence and stride length pair
Pace is cadence multiplied by stride length, and knowing which of the two an athlete changes when they speed up tells you what to work on. Some runners add turnover, some lengthen. The ones who only lengthen tend to be the ones who get hurt.
