My name is Xavi Juanes and KnowPace is my website. I have been doing athletics since I was 12, I compete for C.E. Universitari Barcelona and I am a computer engineer. This site brings the two together: what I have learned from training and racing, and the urge to turn it into guides and calculators that help you train better.

Xavi Juanes running a middle-distance track race wearing bib 482

My Athletics Background

I Started on the Track

I took up athletics at 12, and the track was where I belonged. As an under-16 athlete I ran the 300 metres: three quarters of a lap on a 400-metre track, a race where you go out fast and the last 50 metres feel endless. In that event I competed for the Catalan team and finished second at the Catalan Indoor Championships.

From the Track to the Road

Later I moved to road races, with 10K events and half marathons. My 10K best is 38:04, at the Nocturna de L’Hospitalet, at about 3:48 per kilometre. At the Granollers Half Marathon I broke an hour and a half with 1:29, at a little over 4:10 per kilometre for 21 kilometres.

An 88-Kilo Distance Runner

I do not have a distance runner’s build. I weigh 88 kilos, and carrying that weight through a half marathon costs a lot more than carrying 60. That is why those times mean so much to me: behind them are many hours of training, a lot of consistency and a real love of running.

Xavi Juanes, wearing bib 482, in the pack of a middle-distance track race

Back to Athletics

I stepped away from athletics for years. Two years ago I went back to the track, and I now compete for C.E. Universitari Barcelona in middle-distance races like the one in the photos.

Since then I have run the 800 in 2:09 and the 1500 in 4:41, with hardly any speed work. I know there is room to improve there, and that is what I am training now.

My Goal: a Masters 35 Podium

In athletics, the masters category starts at 35 and is split into five-year age groups. My goal is a podium at the Catalan Championships in the masters 35 category, both indoors and outdoors.

Why I Created KnowPace

I am a computer engineer and I love technology and video games. I also like understanding the numbers behind training: what pace to run an interval at, what time to expect over a new distance, or which heart rate zone I am in on an easy run.

That is where the calculators on this site come from. The race time predictor uses the Riegel formula and Jack Daniels’ VDOT method, the heart rate zone calculator includes the Karvonen method, and the VO2 max calculator is based on the Daniels and Gilbert model. Each tool explains below how it works out the result, so you know where every number comes from.

How I Prepare the Articles

I want you to be able to trust what you read here, so I follow a few fixed rules:

  • Training, nutrition and health facts come from scientific studies, and every article links to the original publication.
  • Race dates, prices and courses are checked on each event’s official website or its registration platform.
  • If a fact changes or someone points out a mistake, I correct the article.

I am not a doctor or a nutritionist. The articles on injuries and health summarise what the studies say, but they do not replace advice from a professional.

What You Will Find on KnowPace

Get in Touch

If you organise a race and want it in the calendar, run a running brand or have spotted a mistake in an article, write to me from the contact page.