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If you are training at CRUfit regularly, we suggest that you consider adding heart rate monitoring to your program. A heart rate monitor helps you identify when you are getting fitter (more work getting done at the same heart rate, faster heart rate recovery, etc.) and can also help you identify when you may need additional recovery time.
Most of our Concept2 rowing machines will work with heart rate monitors that send an ANT+ wireless signal. We have several rowing machines will work with heart rate monitors that send a Bluetooth wireless signal.