The Good: The Oakley Radar Pace is lightweight and comfortable to wear. It can provide real-time coaching and feedback while running or biking, and doubles as a pair of Bluetooth headphones. The Bad: It's expensive. Your phone is required to workout. Battery life could be better. There were occasional software hiccups and missed voice commands. The Bottom Line: The Radar Pace delivers real-time fitness coaching via a voice-activated pair of headphone-enabled sunglasses, and does it better than anything else. I had coaches for most of my running career, six over the course of 11 years to be exact. From junior high and through to college, I had someone creating weekly running plans for me and coaching me to become a faster and stronger runner. That's a luxury not available to everyone, but to me, it matters.In recent years, I've relied on basic training plans available on the web, but nothing satisfied my needs. While most of these programs would provide a weekly workout schedule, few offered actual coaching. That's why I was intrigued when I heard about Oakley's new workout sunglasses. The offers real-time coaching and feedback during your runs and bike rides, via audio cues over embedded Bluetooth . The software can even create a weekly training plan that is tailored to you and your athletic ability. This isn't something that will replace your . There's no step tracking and you wouldn't wear them throughout the day. These are used specifically to track running and cycling. And I really liked what it offered.There are still some kinks that Oakley needs to work out, but the Radar Pace is still one of the most impressive devices I've tested in recent memory, and, at least for now, they're the best fitness-coaching wearable device I've ever used. Just keep in mind the Radar Pace costs $450, \u00a3400 or AU$640, which is more than double the price of Oakley's normal, nonsmart Radar sunglasses. And it's a very different proposition than your average fitness-tracking running watch.How do they work?First of all, these aren't smart glasses, because they don't have any display in them. Alternative gadgets like the Recon Jet and can display workout info in real time through a head-up-display, but the Radar Pace is all about audio. It relies on a voice assistant (like or ) to answer questions and provide coaching. They're also excellent athletic sunglasses. They're lightweight, comfortable to wear and didn't bounce on my face during workouts. The frame is a little thicker than a normal pair of Oakleys, but that's due to extra sensors for measuring movement and elevation. These glasses have an accelerometer, gyroscope, barometer and humidity and proximity sensors, along with Bluetooth and ANT+ for pairing a heart rate strap, footpod, cycling power meter and speed or cadence sensors. But there's no GPS built-in, so you still have to workout with your phone. On each side of the frame are Micro-USB ports. This is how you charge the Radar Pace and they're also used to attach the included earphone pieces, which allow you to hear your "coach" and listen to music streamed from your phone. The headphones can't be used without the glasses, but the glasses can be used without the headphones. A touchpad on the left side of the frame changes songs, adjusts the volume and accepts calls. You can even long-press it to activate Siri or Google Now, but Oakley's voice assistant was more than adequate for all my midworkout questions. Training with the Radar PaceIt's time to go for a run.I turn the sunglasses on, put them on my face and then say, "OK, Radar." A small chime acknowledges that the Radar Pace is now listening. I ask, "What's my workout for today?" A female voice responds, "We are going 4.5 miles and climbing 190 feet." As my landlord watches me, I awkwardly respond, "OK, let's go."It didn't take long for the feedback to come in. The music I was listening to softened, and the Radar Pace chimed in, "Your stride rate is low." I was hitting about 78 steps per minute, but the glasses let me know I should get to 88 steps for optimal performance. "Smaller, quicker steps," the voice told me. On another run, the glasses informed me that my pace was too fast and I should slow down since it was a recovery day.