5 Tips for Including 5Ks in Marathon Training

Q I am training for my first marathon. My longest run to date has been 22 kilometres and I am so excited! My question is this – some of my friends are running a few 5Ks and they want me to join them. Is it ok to do 5Ks when I am training for a marathon? If so, how can I incorporate them into my schedule? I’d like to join my friends but don’t want to sabotage my training. – KAREN


A Thank you for your question and I am excited for you as well. Training for your first marathon is very exciting. Anytime we expand our training and venture into new, unknown territory is scary, exciting, and challenging all at the same time.

Yes, it is absolutely possible and, even advisable, to include some 5Ks in your training schedule. For most runners, a 5K is their first race experience, so it can be a great reminder of where we came from, how far we have come, and where we are now with our training and fitness. It’s also a good fitness baseline measurement.

For obvious reasons, most of our training needs to be race specific. This means we train for the specific physiological demands of our race, which in your case is the marathon. Increasing the distance of your runs builds your endurance so your training will naturally involve many long runs, typically at a slower pace. However, there are benefits to be gained from mixing up our training too. Not every run needs to be a long or slow.

Varying our training offers physiological and mental benefits that can also help us avoid injury and burn out, as well as, improve our fitness. Long runs are both physically and mentally fatiguing. Varying the pace and distance of our runs recruits different muscle fibres, energy systems, running gaits, and reduces wear and tear on joints because our movement patterns are slightly different, so a 5K can give you a break from your usual training. It’s a nice change of pace (literally) to go out the door knowing you don’t need to plan a long route, or carry sports drink and nutrition, because you are “only” running a 5K!

One word of caution though, keep your primary training goal in mind. For now, it’s the marathon, so don’t risk injury or burnout for a 5K. If you feel fatigued from a long mileage week, keep the 5K pace easy or consider skipping it altogether.

Here are five ways you can incorporate 5Ks into your marathon training:

Recovery Run

The 5K can be used simply for fun and recovery. Enjoy a social run with your friends. Keep the pace easy, about 1:15 minutes per kilometre slower than your marathon goal race pace. In this case, do your long run a day or two before the 5K.

Goal Pace Run

Use the 5K as a goal pace run. One training technique is doing a shorter marathon goal pace run the day before your long run. The back-to-back runs provide some extra fatigue on your legs that can help boost your fitness level. Plan your long run for the day after the 5K. Or, you can also practice your pacing skills when testing out your goal marathon race pace and see if you can easily maintain your goal marathon race pace at the 5K distance. Another twist to a goal pace run is to try pacing yourself without the aid of your watch to see how well you can gauge your goal marathon pace. On the other hand, if you are struggling to maintain your goal marathon pace in a 5K, adjust your marathon time goal and your training paces accordingly.

Additional Mileage

When you need more mileage than the 5K, add on kilometres before and/or after the race. Make sure you complete pre-race kilometres just before the start of the 5K so you don’t cool down too much. Run the race, then add on a couple of kilometres post-race. You can use the race as a pace run or push the pace and use the race as a “finish hard” run. For example, if you have 26 kilometres on your schedule, run 20 kilometres before the race and then finish up your mileage with the 5K, either as a pace run or as a race. Finish off the remaining kilometre at an easy pace for a cool down. Or, one of my favourite 5K workouts is this: Arrive early to the race and run the race course easy as a warm up, finishing just before the start. Then, race the 5K. After the 5K, run the course again at an easy pace as a cool down. It’s a tough workout, but you have the race aid stations along the way for water and a crowd cheering you on!

Race it!

Race the 5K. Use it as a barometer to measure your current fitness level. Even if you have not been doing 5K speed work, the additional kilometres of marathon training expand your aerobic capacity, so you may be ready for a 5K PB. Then, you can predict your marathon time from this new 5K time. Also, if you are doing speed work like track intervals or tempo runs, adjust your training times to reflect this current 5K time.

Tempo Run

Use the 5K for some speed work. Tempo pace for marathon training is about 19 seconds per kilometre faster than your goal marathon race pace. If your goal marathon race pace is a 5:37-minute kilometre, then your tempo pace is an 5:18-minute kilometre. Warm up before the race, then hold this pace throughout the race. Another option is to try a progression run. Decrease the pace each kilometre by about 6 to 12 seconds. The key to this workout is picking a realistic start pace, then with each kilometre, drop it down a notch. These type of runs help you practice pacing as well as finishing strong. Getting faster with each kilometre is a great confidence booster. Always do a short cool down when you finish the race.

Most importantly, be sure you listen to your body throughout your training. Knowing when to push and when not to push is essential for success at any distance.


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