The tempo run is a valuable training unit component that should be found in the microcycles of both middle-distance and distance runners, including cross country athletes. The name is derived from a musical term that refers to a recognized “rate of speed”. The rate of speed, or tempo, used in training distance runners is the ground speed employed at the individuals lactate threshold (LT) pace to reach exhaustion. The LT pace is an exercise physiology term that refers to the exact speed at which an individual runs at when the lactate metabolites and hydrogen ions that are being produced in the anaerobic glycolytic energy system cannot be effectively buffered or cleared to maintain homeostasis. As the volume of lactate and hydrogen accumulates in the working muscles from the reduction of anaerobically produced lactic acid, the muscles fatigue. Eventually enough collective fatigue occurs, forcing the cross country runner to stop completely.
The tempo run is an effective training tool that is used to enhance the hydrogen buffering capability of the cross country runner. The tempo run produces lactate at a slower rate than a special endurance 2 workout done on the track might do. It is a bit gentler on the body and thus has a shorter regeneration time period than a fast track workout might have. It t is especially effective in training for races like the 8k or 10k distances because it more closely resembles the specificity of these races. Beyond lactate buffering enhancement the tempo run also redirects glycogen stores to sites closer to contracting muscle fibers. Since the main fuel of the tempo run is carbohydrate, creating storage sites near the working muscle improves running economy. For a miler, two miler, or 5k runner, redirecting carbohydrate storage sites is not crucial to the specificity of the race, but it does help in creating a more fit runner for practice every day. For these reasons the tempo run should be done once in every 12 day middle-distance training cycle and once every 9 days in the cross country training cycle. The nature of the different lengths of microcycles for different endurance events allows workouts to be repeated at the proper training interval. For a 10k runner, doing a tempo run twice per 10 day microcycle would be a proper dosage.
A tempo run need not be a continuous effort but it is usually administered that way. This type of work can be broken up into intervals if desired, but it becomes a technical problem administering the proper amount of recovery. It becomes a real problem if coaching numerous athletes with different training profiles.
A tempo run is usually 20-25 minutes in length. Since it needs to be done at the lactate threshold pace of each athlete, the coach needs to refer to each athlete’s VO2 max pace in order to set up the proper individual training intensity. As you recall, VO2 max pace is the pace that a runner uses to run two miles to exhaustion. This is the athlete’s aerobic capacity. A cross country runner’s lactate threshold pace is between 60%-88% of VO2 max pace (Figure 1. Wilmore and Costill 2004). The variation is found in the runner’s training age, genome, and date fitness. This is the time to individualize the workout for each athlete. Use your experience as a coach to determine where in that range each athlete falls, and assign each a percentage for their threshold. Then divide that percentage number into their VO2 max pace. That will give you the important value for each of your athletes: lactate threshold per mile pace. Find a good 4-4.5 mile course and multiply their per mile lactate threshold pace to the distance and you have an individual time goal for each athlete for the tempo run that day.
Figure 1. (Wilmore and Costill 2004)
Scientists have said that lactate threshold pace is about the intensity of 15k pace for each athlete. That can also serve as a good reference point for you in setting up individual pace and goal times. A good way to administer the tempo run is to stagger it. Handicap the best runners by sending them out last. The least proficient runners precede them in a calculated way so that if you are good with numbers everybody finishes at the same time. It is good for the best runners to be catching people along the way while the others attempt to hold their own. Remember though, this workout is not a race. It is a disciplined 25 minute run at about individual 15k date pace.