hrOTS for Running, Multisport and XC Skiing (to name a few)
This is also essential for bikes that don't have power meters. I don't have a power meter on my cx bikes and wouldn't use power in case I have to pit throughout the race.
Weightlifting is another good example of being able to capture the effort you put into it and it is based on your workout and HR.
Sarah Larson: yes, agree 💯 heart rate OTS is so important as is developing the technology to quantify the benefits of weight lifting. We are working on this technology! In the case of weight lifting hr is not the answer - its more about using the amount of weight lifted multiplied b the # or reps.
For swimming hr is good but I think we'll run into the problem where not everyone is keen on wearing a heart rate monitor. Pace x laps may be the way to go here!