This is a request for a rowing (crew)-specific app(s) on the Vivoactive.
The important rowing-specific metrics are:
- split time (pace) in minutes, seconds and tenths/500m e.g. 1:34.3
- stroke rate in strokes/minute (spm)
- Distance per stroke in metres/stroke - helps the rower determine how efficient each stroke is
A basic rowing app might just display the split time computed from smoothed GPS speed (along with HR and speed).
A more advanced app would also show stroke rate, and distance per stroke.
The stroke rate should based on one or more of the following (user selectable?):
- by detecting the wrist motion during each stroke from the accelerometer
- by detecting the surging motion of the boat with each stroke from the accelerometer. For this the watch may need to be strapped to the rigger, or otherwise placed on the boat rather than the wrist. This is the way apps like Boatcoach work, and products such as NK Speedcoach GPS
- using a bike cadence sensor attached under the seat so that the seat magnet passes it twice per stroke. Since this produces 2 "cadence" readings per stroke, and the stroke is asymmetrical back and forth, it needs some smoothing, and then dividing by 2 to give stroke rate.
- using a rowing cadence sensor such as http://www.vaakacadence.com which appear as bike cadence sensors, and have inbuilt smoothing. Since they report 2x stroke rate, the reading needs to be divided by 2
Note: The ANT+ bike cadence protocol requires a rotation at least every 3 seconds otherwise a cadence of 0 is transmitted, therefore the minimum bike cadence possible is 20rpm. Whilst rowing racing stroke rates are >30spm, typical paddling stroke rates are <20spm so it is necessary to use 2x stroke rate when using ANT+ cadence sensors for rowing.
Distance per stroke is based on the stroke rate and speed from the GPS. This will no doubt need some smoothing to be useful.
An even more advanced app might have some race timing functions, and display rowing time
- for head races where the watch detects when you pass the start line and the finish line, and give a forecasted race time based on progress, and an actual race time based on passing the finish line
- for regattas where the watch detects the start of the race from the first stroke and the finish from passing the finish line
It would also be nice to detect power over ANT+ from the powertap HR/power sensor.
This would make the Vivoactive an awesome rowing tool since it is waterproof, has GPS, ANT+, and an accelerometer.
