It's the next best thing to having your own personal running coach. Forerunner 620 features recovery advisor, race predictor and VO2 max estimate so you can train smarter. When used with the HRM-Run monitor, the 620 also gives you feedback on your running form by showing your cadence, ground contact time and vertical oscillation. For indoor training, the built-in accelerometer tracks distance, so you don't need a separate foot pod. Advanced Running Watch with Recovery Advisor Touchscreen GPS running watch with high-resolution color display that tracks distance, pace and heart rate Calculates your recovery time and VO2 max estimate when used with heart rate HRM-RunTM monitor adds data for cadence, ground contact time and vertical oscillation Connected features (Compatible with iPhoneÂ® 4S or later): automatic uploads to Garmin Connect, live tracking, social media sharing Compatible with free training plans from Garmin Connect It Knows Your Potential Forerunner 620 can estimate your VO2 max, your body's maximal oxygen consumption. Knowing your VO2 max is a great way to measure your physical fitness and improve your performance. When used with a heart rate monitor, the 620 crunches data, including your running speed, beats per minute and heart rate variability to estimate your VO2 max. The number itself indicates the maximum volume of oxygen you can consume per minute, per kilogram of body weight at your max performance. A color gauge on the watch shows how your VO2 max data compares to other runners of your gender and age range. Based on your VO2 max estimate, the 620 can predict your race times for several distances. This can give you a time target for your next race, assuming you've completed proper training.