Polar's latest watches know if you're maximizing your workouts

They also tout more accurate heart rates and measure your running power.

Polar has a way to compete against ever more fitness-savvy smartwatches: offer exercise tracking that's difficult to match. It's launching two fitness watches, the Vantage V (above) and Vantage M (below), that promise more insights for particularly committed athletes. Both include a Training Load Pro system that melds cardiovascular, muscular and perceived loads into a single metric that gives you a sense of just how effective your workouts are. You'll have a better sense of whether you're overreaching or need to ramp up the intensity. The pro-oriented Vantage V adds a Recovery Pro system whose daily and long-term tracking help you understand when your body has had enough rest.

The two watches also tout more more accurate heart rate monitoring that uses multi-layer optical sensing, electrodes and accelerometers to get both faster and more accurate heartbeat readings. Spring for the Vantage V and you'll also get running power data (a first on the wrist, Polar said) that helps you pour more work into every stride.

Polar is taking pre-orders for the wristwear today, although you may need to brace your wallet for impact depending on what you're buying. The more mainstream Vantage M sells for $280, but the Vantage V will set you back $500 ($550 with an external heart rate monitor). The V's cost is easier to swallow if you're a serious competitor -- just know that it's likely overkill if you aren't chasing a place on the podium.