Tempo Tantrums

The Tempo Run or as many call it, a Lactate Threshold run, is one of the key elements of any well planned training routine. It is generally defined as a "sustained comfortably hard run" inserted between a 1-2mile warmup and cooldown. If you consistantly add this workout to your regular routine you will see benefits at all race distances from the 5k to the Marathon.

A tempo run is run at a pace where your body begins to accumulate lactic acid in the bloodstream. Accumulating this byproduct of carbohydrate metabolism in the body is bad because it causes an acidic environment in the muscles forcing you to slowdown. We would also like the body to learn how to use this fuel more efficiently because a runner's speed at lactate threashold pace is the primary determinant of race performance from the marathon on down to the 10k. Running at this pace provides the best stimulus for your energy systems to adapt and thus lower your threshold for lactic acid buildup.

So what is a comfortably hard pace for me and how long should my tempo runs be? There are many ways that you can estimate your current lactate threshold pace. For many runners it's a pace that can be sustained in a race of about an hour in length or about 15-20secs slower per mile than your current 10k race pace. You can also input any recent race in the McMillan Running Calculator and find your tempo pace under the "Stamina Workouts" header. It's best that this race represents your current level of fitness so make sure it's recent and run at maximal effort.

Tempo runs are no less than 20min and usually no more than 45min unless you're doing some serious marathon training. If you are just getting used to speedwork a good introduction to tempo runs are "cruise intervals". You can think of them as punctuated tempo runs with a short rest after each mile. If you have trouble maintianing a harder effort for a long period of time cruise intervals are a good stepping stone to longer efforts. Start out with 3xmile with 1min rest in between each, or, do 2x10min with 1min rest. Once you get used to maintaining this effort you can shoot for a full 20min at that pace.

For longer tempo runs you can slow the pace down slightly. For each addtional 5mins you can add about 4-6secs/mile to your threshold pace. For example, if your 20min threshold pace is 7:30/mile and you want to run a 35min tempo run you can slow the pace down to 7:42-7:48/mile and still provide a strong stimulous to your lactate clearance. The key to all tempo runs is to run them at an even effort throughout. You want to keep your pace just at or slightly above your threshold to reap the biggest rewards.

So when should I fit my tempo training into my schedule? Most runners will run their tempo workouts on either Thursday or Friday if they usually do hard speedwork earlier in the week. If you are just starting out with speedwork you can alternate one Wednesday or Thursday of intervals with a tempo run the next week. I sometimes like to run a tempo run on the day before a long run so I start my LSD slightly more carbohydrate depleated. It can make a 15mi long run function more like an 18mi run. Low key races are also a great way to get in a tempo run. Just make sure you don't go too fast!