Sure, the term “tempo run” does not conjure up the same images as “speed work,” but as former Olympian and long-time running guru Jeff Galloway says, “There are many different roads that lead to race fitness,” and there’s no denying that tempo runs play an important role.

Just what exactly is a tempo run, and physiologically, how does it differ from speed work? Jack Daniels, one of America’s foremost exercise physiologists, and widely considered to be one of the greatest running coaches of all time, explains.

Tempo runs are key predictors of race performance, and are less likely to result in injury.

“Tempo runs are designed to increase your lactate threshold. Interval training is about increasing your maximal oxygen consumption (VO2max),” says Daniels. “The goal of interval training (speed work) is simply to spend as much time as possible running at VO2max—so quite fast. Recoveries are slow jogs about as long (in time, not distance) as the interval.”

For example, each 400-meter repeat would be followed by a 60-90 second jog. When you run intervals, lactic acid begins to build up; too little recovery leads to too much blood lactate, which compromises your ability to complete a good workout. Tempo runs help push your lactate threshold further back by teaching your body to clear out the lactate buildup more quickly.

And like intervals, tempo runs also help increase your VO2Max, and as a bonus, actually signal your body to make more capillaries in the working muscles, thus increasing more oxygenated blood to the muscles.

“Tempo runs help you improve your lactate threshold,” says Daniels. “The goal is to run comfortably hard, or at near-anaerobic threshold, which amounts to 85 to 90% VO2max.”

According to Daniels, your tempo run pace is roughly what you could sustain for one hour of racing— so it’s considerably slower than interval training. Depending on your fitness level, this would translate to roughly 30 seconds per mile slower than your 5K pace.

Most running experts recommend tempo runs of around 20 minutes or so, but if you’re training for a half or full marathon, you’d probably want to increase that to around 35-40 minutes. Or from a distance standpoint, four to five miles.

While there is no denying that interval training is the most direct route to increased speed, studies have shown that lactate-threshold speed (which tempo runs build) is the best predictor of endurance performance. In short, both forms of training have their place. But tempo runs do have one added benefit: you’re less likely to get injured while building speed.

So if you find that every time you add speed work into your training you wind up with an injury, try tempo runs instead. As Galloway says, “there are many roads to get you there.”

Upcoming races: Saturday, September 9, Hornet Race 5K, 7:30 a.m. at Tom Green Elementary in Buda. Sunday, September 17, CASA Superhero Run 5K, 8:00 a.m. at Domain Central Park. Also Sunday, September 17, LIVESTRONG Honor 5K and 10K 7:30 a.m. at Auditorium Shores in Downtown Austin.