In running a half marathon you want to sent your pace correctly to ensure optinum performance, reserve enough energy to complete the run, and avoid injury.
I have been doing research on a number of issues related to running a half marathon and the following is what I found on pacing yourself.
Run a number of 5k runs to get your personal best and your corresponding pace. Go out hard and then adjust your pace when you get into deep oxygen debt until you find the right pace.
Using the numbers from your 5K personal best apply the 20 sec/mile (12 sec/Km) slowdown rule of thumb to get your pace for 10k. Run a number of 10Ks and adjust your starting pace in the same way you did with the 5K until you have a personal best.
Once you have your pace for 10K add the 20 sec/mile (12 sec/km) slow down rule of thumb again to get your pace for a half marathon.
I can run a 5K in 28:30 which is a pace of 5:42/km. According to the above rule of thumb with proper taining my target pace for a half marathon should be 6:06/km which would give me an overall time of 2:08:42 which seems about right.
I am quite sure I couldn’t pull 2:08:00 off at this point but with a proper training program I should be able to do close to that time.
I did my first half marathon (21.32km) on the Springwater trail in 2:53:16 which is a pace of 8:07/km. The main concern I had with my frist half marathon was just to finish so I set myself a pretty slow pace. After you know you can make it through a half marathon, work out an appropriate time goal by using the 12 sec/km slowdown rule of thumb to your 5km and then 10km times.
I came up my own training route of 21.1km on the Springwater trail in Aylmer that works out to three 7.1km laps. Three of these laps will give me very close to the 21.1km half marathon distance. So to get a 2:08:00 time on 21.1km my time per lap need to be 42:40.
On Saturday I did the 7.1km lap in 43.26 for a pace of 5:58/km but I don’t think I would be able to keep that pace up for 3 laps.
Running in a half marathon event is a bit different than laying out your own half marathon and running it by yourself. Typically you are positioned according to your past half marathon times. It will be pretty crowded at the start but just settle in and don’t wear yourself or knock someone over by zig-zagging. Just go with the flow and as space opens up move to the pace you have calculated for yourself.
Check your progress every kilometer mark and adjust your pace accordingly in the following kilometer. The idea is to run the whole race at the same pace or at the same energy expenditure if there are lots of hills.
Some trainers recommend running the first 3km slower as a warm up, running the 4 to 18km at your set pace, and then runninng the last 3km at a slightly faster pace to make up for the slower time in the first 3km.
Knows the course will help you to prepare to pace any hills there is in the run. You need to slowdown uphill and speed up downhill as you want to keep your energy expenditure even throughtout the race.