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The following post is sponsored by FitFluential LLC on behalf of Under Armour. Must confess, before using Under Armour's Armour39 I have had a somewhat negative attitude towards the usefulness/relevancy of heart rate monitors in my own training.  Part of this was due to past experience with bulky plastic HRM straps collecting sweat across my ribs and only providing very … [Read more...] about Under Armour’s Armour39 Performance Heart Rate Monitor