Hoe goed ben je als je wat ouder bent? - Je PR begint bij ProRun
Polar - What's your running VO2max? 🏃💨 For beginners and experienced exercisers alike, a higher VO2 max can make workouts feel easier, lower your 5K or 10K times by a significant margin,
Your un/success stories with Polar Running program? : r/Polarfitness