A a rare achievement achieved by only a select few men and women, the 16-minute 5K requires national class athleticism. Only 21 Division 1 college women ran under 16 minutes for 5K in the 2012 outdoor season, according to the Track and Field Results Reporting System. Being able to string together three miles at an average pace of 5:09 per mile requires a blend of natural talent, hard work and and the right combination of workouts. These workouts fall into various categories based on the physiological systems they affect most strongly.
Basic Aerobic Endurance
The most important factor determining whether you can run a 16-minute 5K is your basic endurance. Leg speed among runners in this range varies widely, but all of them are unusually efficient at processing oxygen thanks to a combination of favorable genetics and diligent training. A universal, magic number doesn't exist to prescribe the number of miles a week you need to run or length of time you need to maintain this workload to reach 16 minutes or any other time goal. However, only the most gifted runners will maintain this pace on about five miles a day, and the majority require closer to 10.
Interval Workouts
While interval workouts represent a small fraction of your overall training, they are vital to success in the 5K, as these workouts provide race-pace-specific preparation. Run fast for about three miles total, broken into segments of 400 to 1,600 meters, and separated by rest intervals about equal to or slightly shorter than the intense portions. Rick Morris of the Running Planet website suggests workouts such as 10 times 500 meters, five times 1,000 meters and three times 1,600 meters, all with two-minute rest. A runner aiming for a 16-minute 5K would run these in 1:36, 3:12 and 5:07 respectively.
Tempo Runs
The term "tempo run" -- also called a lactate-threshold run or anaerobic-threshold run -- was coined in the late 1980s by exercise physiologist Jack Daniels. It refers to a run about 20 minutes long done at an effort level where your body's production of lactic acid just begins to exceed your system's ability to clear it -- abot 25 seconds per mile slower than 5K pace for faster runners. The idea behind these is that they teach your body to better metabolize lactate and thereby "push back" your anaerobic threshold. Given that you need to average about 5:10 a mile to reach 16 minutes for 5K, a tempo run for an athlete of this caliber is about four miles at 5:35 per mile.
Long Runs
Exercise physiologist and two-time Olympic marathoner Pete Pfitzinger explains that seven special benefits to doing one especially long run every week or so. Among these are increased blood supply to working muscles, an enhanced processing of oxygen in these muscles, improved oxygen delivery to muscles and more efficient utilization of both fats and carbohydrates. Marathon specialists routinely exceed 20 miles in training runs, but as a 5K aspirant, 15 miles is sufficient for most. Aim for running these miles at about 75 percent of 5K race pace, which translates to 6:50 a mile for a prospective 16-minute race.
References
Writer Bio
L.T. Davidson has been a professional writer and editor since 1994. He has been published in "Triathlete," "Men's Fitness" and "Competitor." A former elite cyclist with a Master of Science in exercise physiology from the University of Miami, Davidson is now in the broadcast news business.