When we think of hills, we often think of running uphill but overlook the fact that going down, down, baby has its benefits too. The burning sensation in your quads after running hills is from the downhill pounding when your muscles lengthen, not from the uphill climbing when muscles contract. Mastering downhills with the right technique will put less stress on your legs and help you run faster.

3 tips for downhill running:

Avoid over-striding: Your feet should strike the ground underneath you near your center of mass, instead of out in front which produces a braking effect. Over-striding results in landing on your heels, placing more strain on your body. Drive from your hips, lift your knees, and increase your stride rate to land softly on your mid-/forefoot, springing right off again.
Run tall and forward: Rather than look at your feet, keep your gaze out and down the hill with your posture upright. Engage your core and find a slight lean forward from the hips to battle the tendency to lean back and slow down. Keep a slight bend in your landing leg to avoid absorbing all the impact in your knee.
Let it go: Let your mind and body go. This means not thinking about falling or braking and instead opening up your stride and using your arms to balance. Run with confidence and purpose. This is the only time where I will tell you it's OK to flail your arms like a chicken and not drive straight up and down like an antelope.

Suggested workout:
Stay focused on downhills during your training runs. There's no need to seek out steep drops and introduce excessive impact unless you're training for a trail race. Use gradual declines, ideally on softer surfaces, and start with 5 downhill repeats for 30 seconds to 1 minute each at your 10k race pace or 85% effort. Jog back uphill at your recovery pace, working up to 10 repeats at 5k pace or 90% effort over the course of a training program.