Progressing to the Half Marathon from 10k
The half marathon is one of the most popular race distances for UK runners. For many, it represents the sweet spot of being a significant endurance test while also fitting in to a runner’s wider life more easily than training for a marathon. That said, the step up from 10K to half is still significant and requires focus and training. In this article I want to focus on your achieving your first half marathon and I am assuming you are comfortable with running 10k.
Understanding the Half Marathon
Training for 10k shares many of the same components as half marathon training so you already have a good platform. Both distances rely to a large extent on aerobic capacity (as they are both endurance events) and thus developing a lot of sprint speed capacity (through a refined anaerobic energy system) is a largely a waste of training time.
The general training foundation required is likely to be very similar to what you are used to, and importantly what your body has already adapted to! This would include a significant volume of easy runs between 45 and 75 minutes at a low intensity (this would be at zone heart rate or Easy or Endurance Pace if you use the vDot training system). It might include some short, faster hills over eight to 12 seconds to help build power. Regular strength training can be helpful to ensure that you are creating resilience in your tendons, as well as developing strength with a much lower injury risk than fast outdoor running. You will include a run where you increase your effort to ease yourself into the faster training later and also to provide a different training stimuli to help ensure continued adaption. Despite these similarities, there’s no doubt that, being over twice the distance of the 10K, the half marathon has some specific demands runners need to prepare for too.
How it differs to 10k
Running a 10K and a half marathon impose some slightly different metabolic demands due to the differences of intensity and duration of each. For some experienced runners, a 10K can actually be run at an intensity that pushes beyond the ‘lactate turnpoint’. This means that, during a 10K, you’ll be burning quite a lot more carbohydrate and generating fatigue at a much more rapid rate than during a half marathon. A half, for all but the fastest and elite athletes, is run slightly below this ‘turnpoint’, which means that finding and developing your ‘maximal lactate steady state’ should be one of the priorities in your training. This is an effort faster than your normal running pace, but where you’re still able to stabilise your effort and not find each kilometre feeling harder than the previous one.
Threshold runs can be a very effective tool in half marathon training and help you get more comfortable with running for longer periods around your maximum lactate steady state. Start with 20 minutes of effort where you can speak four words or so at a time, at around a pace you feel you could hold for 60 to 70 minutes in a race. As the weeks go by, build this up to 30 to 40 minutes of work either as a straight run or broken into blocks (eg, 3 x 10 minutes with short recoveries).
Threshold runs are all about intensity regulation. If you’re struggling to stay in control during a 60-minute race effort, back off by 10 to 15 seconds a mile and focus on building up minutes you can spend while still in control. Remember that training is about learning about your capabilities and mental fortitude as much as it is about physical adaption.
Adapting your body to the rigours of the extra distance is obviously a key part of half marathon training. The extended duration means more repetitive strain on your muscles and a greater likelihood of fading in the latter stages of the race if you have not managed your energy systems (though pace and nutrition). As such, the core of your plan to build from 10K to half marathon should be about progressively building volume. You might consider starting to add more time to your long run, including another short 45-minute run to your week or adding 10 to 15 minutes on to some of your existing runs.
The long run plays a much more important role in half marathon training than it does when preparing for the 10K, and for many weeks it will probably be your key critical run of the week. Remember to apply the 10% rule and consider increasing your long run perhaps every two weeks, building to long runs of 120 minutes. In the final build block of your plan, consider adding some race-pace running into the final 45 minutes of your long runs (initially start at the final 15minutes and then add from there). Without a doubt the best way to improve your running is to run! However as you increase volume in half marathon and marathon training, this can start to impose a lot of accumulated stress, with ensuing risk of injury. To help balance this consider cross-training, such as cycling, elliptical training or swimming, can boost your endurance with less impact. The fitness gains you get will be highly transferable as will the muscular strength.
The Need For Speed
For your first half marathon, hitting an aggressive speed is not needed or sensible. However building speed (judiciously) in training will greatly support your ability to comfortably finish the half. Increasing speed is one of the levers we use in progressive overload training. Your training mix should include some running at your current half marathon pace, but also your goal pace, building this up over time.
While the core of your half marathon plan will be made up of easy and steady running, longer runs and tempo runs, some occasional quicker interval efforts will help. This is the principle of 80 / 20 training. Interval work in half marathon training should be about control, running just a little faster than your goal half pace. An appropriate set might look like 10 to 12 x 3 minutes run at 10K pace. As you get closer to race day, focus on building the length of your efforts or number of repetitions rather than worrying too much about running them faster. Always remember that as you get closer to your race, your training should become more race specific, that is each session looks increasingly like the race you plan to run. Therefore sprints and 5k pace are not likely to feature at all. 10k pace maybe but not for any protracted period.
It Is All About Adaption
We train to adapt. As we adapt our bodies become capable of more. We adapt when we REST and RECOVER not when we are stressing our body. Changes to your training plan will only bear fruit if you can adapt to the training. That means not getting injured, making progressions gradual and building in recovery time... For some athletes I coach we don't talk about "recovery time" we reframe this to "adaption time" which you might find helpful too.
Place as much focus on your recovery and nutrition as you do on your active sessions and make them part of the plan. Consider moving beyond a weekly structure with your plan. This can create more opportunity to include a variety of sessions without cutting or impacting on "adaption time". Consider planning your training over a 14 or 28-day cycle.
Tapering is essentially the process of cutting back your training to make sure that you’re recovered enough to perform your best when race day comes. It is also really hard to do and you will often feel physically and mentally "rough"! This happens more if you go into Marathon training or start doing longer multi-sport. You have developed a really strong training habit. Your body is used to not only the load, but also the endorphins and many mental health benefits. So reducing training for a taper can be unsettling! However, come race day you need to be properly rested and your muscles need to be fully loaded with glycogen. Plan a period of taper training and decrease life stress for two weeks before the race. Aim to trim back your long run a week before the race to 40 to 60 minutes maximum, and tick over in race week with 30-minute runs and a handful of SHORT efforts at race pace.
The key to the taper is recovery time to let your muscles be as fresh and fully fuelled as possible at the start line. You have trained for weeks and adapted from that training. The reality is you ARE NOT going to gain anymore fitness in the last 14 days before the race. And vitally (this is the bit you need to keep reminding yourself) you are NOT going to lose fitness in 14 days either. Your mind will tell you other wise ("Have I done enough?") but you are wise enough to be able to manage those worry thoughts.
The Half Marathon is a great distance; it is a challenge but one that is manageable to train for without having to close down the rest of your life. You need a sound platform to build on, but if you are a competent 10k runner (you could go out right now and run 10k and not bat an eyelid - it is your go to distance), then having fabulous fun at the Half Distance is well within your reach. Enjoy it and smile as you sprint for the line!
If you would like any specific advice or guidance, bespoke training plan, or just a bit of direction to get you going; please feel free to contact me via my coaching site.