I used the Decathlon app for five months to run a half marathon

Two years ago, I got more serious about running by signing up for different races. First the Paris half-marathon in 2023, then the Paris marathon at the start of the year.

For each preparation, I took the opportunity to test different running training applications, whether it was the Garmin Coach program offered by the American manufacturer or the French Campus Coach platform.

At the end of October, I had the opportunity to participate in the Bois de Vincennes half-marathon, with the aim of improving my previous time. And to do this, I spent five months training with Decathlon’s free running app: Kiprun Pacer.

A free and easy-to-use application

The first impression of Kiprun Pacer is quite positive. After creating a Decathlon account (I have never received the slightest spam in five months), the application will try to evaluate your profile.

To do this, it will ask you the units to use (metric or imperial system), the objective of the training (preparation for a road race, a trail, maintaining shape or simple progress). In my case, I logically opted to prepare for a road race, then I had to give a name, a date and a distance to this race, as well as a time objective: 1h49 and 59 seconds. All you have to do is tell the app when you plan to start the training program and off you go.

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To find out more about your profile, the application may also ask you for some information in order to optimize training, first with your VMA (maximum aerobic speed), expressed in km/h, as well as your track record.

All you have to do is link your Decathlon account to that of your connected watch (Garmin, Polar and Coros) to transmit the sessions to your sports watch.

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Unfortunately, Suunto and Fitbit watches are not supported for scheduling sessions, but Kiprun Pacer can still retrieve training data from your profile for these two brands, as well as from Strava.

Last part of the initialization, Kiprun Pacer will ask you your current state of form to know if you prefer to start strong or gently over the first weeks. It is then that you can program the number of sessions per week as well as the training days.

Overall, getting started with the application is particularly simple and I felt supported from start to finish with this initial configuration. The options were simple to understand, well explained and sometimes necessary.

Kiprun Pacer also has the advantage of being completely free. In fact, Decathlon seems to monetize its application through different tips. In addition to the cooking recipes offered each day, the sessions are accompanied by some tips for recovery, hydration or refueling. Advice which obviously highlights the products of the sports brand.

Workouts based on two paces

Unfortunately, from the first weeks of training, a gap was felt in terms of initialization. Although I was able to indicate my training days – Monday, Tuesday, Thursday and Saturday in this case – I was never able to schedule the day of my long outing.

To prepare for a long 10 km race, but especially a half-marathon or a marathon, you have to get used to running longer and longer, generally with a dedicated session each week. However, at no time did Kiprun Pacer ask me which day I preferred to select for this session, unlike Campus Coach. So I found myself with 20 km sessions in the middle of a Tuesday evening, whereas, by default, I would have tended to schedule this outing for the weekend.

Never mind, fortunately it is possible to reorganize your sessions as we see fit, provided that they all take place in the same week.

For the rest of the training plan, Kiprun Pacer offers a relatively classic program composed of three phases: one month of speed training, to increase my VMA, three months of specific training for the half marathon and a few weeks of sharpening, to maintain my shape while reducing fatigue.

The first weeks, focused on intense sessions of split intervals, actually allowed me to increase my VMA, but with a catch. It must be said that the application requires carrying out a half-Cooper test (six minutes at maximum and constant intensity) and is based, theoretically, on the GPS data from the watch. Except that, in my case, I did the session on the track and measured a VMA of 14.7 km/h. For its part, the GPS of my Garmin Forerunner 255 measured a distance of 1.52 km, therefore a VMA of 15.2 km/h. Let’s admit, GPS errors happen… Where the problem lies is that, based on the same data as those from Garmin, Kiprun Pacer estimated my VMA at… 15.8 km/h.

As a result, a good part of my sessions were distorted, based on poor analysis, or even unachievable, even if it is possible to manually modify your VMA.

Concretely, the Kiprun Pacer program is actually based on two types of paces. First, those around your racing goal, for specific sessions at half-marathon pace. These generally went very well.

The second workouts are based on your VMA estimate and this is where the problem comes in. As my estimate of VMA was distorted, I found myself, over one session, having to run 10 km more and more quickly, starting from a pace of 5:24/km up to a pace of 4:19/ km. Suffice to say that at my level, it was mission impossible.

It also happened to me on several occasions, particularly at the start of the program, to feel some discomfort in my Achilles tendons. This is logical with the intensity and pace requested by the application. Fortunately, it is possible to provide feedback after each session, both on the pleasure felt as well as the difficulty of the session or potential discomfort. If the session is too simple, Kiprun Pacer will then suggest more difficult subsequent sessions. On the contrarya session that is too difficult, having caused some pain, will result in lighter training in the following days, while time to recover.

Overall, the program is well constructed, with varied sessions, mixing long active endurance outings, VMA sessions, progressive sessions, pyramid outings and threshold or half-marathon pace training. It also offers, in each phase, blocks of four weeks with three weeks of gradual increase in load and one week of assimilation.

In short, enough variety not to get bored and make good progress week after week.

Race day, failure

We now arrive at race day, Sunday October 27 in the morning.

As a reminder, my goal was relatively simple: to run this half marathon in less than 1 hour 50 minutes, therefore at a pace of 5 minutes and 12 seconds per kilometer. It must be said that this was already the objective that I had set for myself during my first half-marathon, in March 2023, but I then had a time of 1h52 and 58 seconds. In short, I just had to squeeze in these three minutes.

I was relatively confident at that time, because, a few weeks before the half-marathon, I had run a 20 km session at a progressive pace, in 1 hour 45 minutes and 44 seconds. Concretely, it was playable, especially after two weeks of sharpening and rested legs.

However, the problem quickly arose. From the first kilometers of the race, my heart rate rose too quickly, too high, and my legs quickly became too heavy. It must be said that my two weeks of sharpening were accompanied by two weeks of illness, with coughing fits that woke me up at night. In short, the calendar is bad.

Finally, after the tenth kilometer, I ended up letting go of the ramp and, little by little, my mind failed me. I stopped to walk several times. I finally finished the race in 1h57 and 3 seconds, more than four minutes behind my time at the 2023 Paris half marathon.

Obviously, the criteria for this failure are multiple, and the illness necessarily had a great influence. It may also be that the timetable given by Kiprun Pacer was a little too advanced, with a peak week of training, at 63 km, six weeks before the race. In the meantime, I only traveled more than fifty kilometers for a week. In short, my sharpening may have started a little too early.

Overall, however, I felt real progress over these five months of training. If I’m frustrated at not being able to mark it with a new personal best, I’ll probably try again, this time aiming even a little higher. And, why not, aim directly for 1h45.