If you have run a marathon or half marathon recently, you will have a rough idea of what your goal pace should be for that distance. For many Safari participants, however, the upcoming event will be the very first half or full marathon. Others may not have run the distance for an extended period of time and fitness levels may have changed. So how do you select your goal pace? Your training run and lactate threshold pace can give you a general indication, but a recently completed race of another distance can often be a great predictor of what your goal pace should be. Races used for prediction purposes should be run at a best effort. Also, races closer in distance to the goal race are a more accurate predictor than a much longer or shorter race. For example, the half marathon is a much better indicator of marathon time than a 5k is.
For the half marathon, a recent 5k, 10k, 10 mile or even marathon time can give you an excellent indication of what your half marathon finishing time or goal pace should be. You can use the following conversion factors to determine the corresponding half marathon time and then use a pacing chart to determine the appropriate pace.
10 mile 1.33
For example, if your 10k time is 50 minutes (3000 seconds), your predicted half marathon time would be 6720 seconds (3000 x 2.24) or 1:52 or about an 8:30 min/mile pace. Likewise, if you ran the Crim in 1:30, your corresponding half marathon time would be 7182 seconds (5400 x 1.33) or 1:59 or about a 9:02 mile pace. Recently ran a marathon? A 3:30 marathon, 12,600 seconds, would correspond to 5947 seconds for a half marathon (12,600 x .472) or a 1:39 or about a 7:30 pace.
For the marathon, a recent 10k, 10 mile or half marathon can provide a good indication of what your marathon finishing time and goal pace should be. Again, you would use the conversion factors below, than refer to a pacing chart to determine the appropriate pace for the predicted time.
10 mile 2.82
For example, with a recent 10k time of 50 minutes (3000 seconds), your predicted marathon time would be 14,280 seconds (3000 x 4.76) or a 3:58 marathon. If you look at corresponding pacing charts, this would be about a 9:02 min/mile pace. If you recently ran a half marathon at 1:40 (6000 seconds), your corresponding marathon time would be approximately 12,720 seconds (6000 x 2.12) or 3:32, which corresponds to about an 8:02 pace.
Keep in mind there can be many other factors that can impact your performance. Race time conversions, particularly from a much shorter distance, can be a bit aggressive for the first time marathoner. Training specificity, weather conditions, hydration and fueling are just some of the factors that can heavily impact performances. For example, you can have two people who ran a 40:00 min 10k. One may completed two 20-milers while the other wasn’t able to complete anything over 13 miles. The runner who trained specifically for the marathon will be more likely to run the predicted time, than one who has focused their training specifically on shorter distances.
Reference: Pfitzinger, P., and S. Douglas. 1999. Road Racing for Serious Runners.Champaign,IL: Human Kinetics.