Swim tracker accuracy not good enough for serious swimmers says study

Listen up Michael Phelps wannabes, the current crop of swim trackers are not up to the task for hardcore swimmers according to a recent study.

Researchers at the National University of Ireland in Galway found that swim-friendly wearables are actually only cut out for recreational swimmers. They cited inconsistency of stroke counts and issues around the ability to recognise different stroke types.

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Senior study author Gearoid O Laighin and his team used the Finis Swimsense and Garmin Swim trackers, which are admittedly some of the older dedicated swim devices available.

The two trackers were tested by strapping them both to 10 national competitive swimmers (five men and five women) for 60 laps of swimming. Swimmers performed intervals of the butterfly, backstroke, breaststroke and frontcrawl and accuracy comparisons were made with underwater video recordings.

The results...

Both devices managed to identify the different swim strokes, with the Garmin Swim managing a 95.4% accuracy for overall sensitivity and the Swimsense managing 96.4%. They both overestimated stroke counts though apart from the butterfly. Breaststroke offered the lowest accuracy of all strokes.

In terms of distance tracked, the Garmin wearable was three laps short while the Swimsense counted correctly but varied within strokes. For lap intervals, the beginning and end of an interval didn't always prove accurate, which in turn can have a negative influence on other aspects like stroke rate, length and average speed.

While the research team believes the two trackers were pretty good at monitoring pool action, it does suggest improvements on feature detection algorithms, specifically for lap time and stroke count to make them more suitable for competitive settings.

It's a bit of a shame the Apple Watch Series 2 and newer Garmin devices like the Vivoactive HR and the Fenix 3 HR were not in the testing mix. But it's perhaps not all that surprising that we're talking about algorithms here as we have seen with fitness trackers and questionable step counting.

When we tested the Swim back in 2014, we were pretty impressed with it but this study does shed more light that wearables whether on land or water, still have a bit of an accuracy problem.

Source: Reuters via PLOS ONE