The Smartest Way to Run a Faster 5K (Science Explained)

If you’re new to my channel, my name is Nicklas Røssner. I’m a performance specialist, physiotherapist, and former national team triathlete. For over 20 years, I’ve dedicated my life to reverse-engineering world-class performance—not just for myself but also for the athletes I’ve coached and mentored along the way. Given this is a YT channel, and anyone can claim anything, I’ll give you some stuff you can google to verify below.

How I got here…

11 yrs old: Started competing in cycling, discovering my love for endurance sports.
15 yrs old: Became a Team Denmark-certified athlete and raced for the youth national team.
19 yrs old: Hit rock bottom. Burned out and quit cycling, thinking I’d never return to elite sports.
20 yrs old: My dad asked me to compete in a 24-hour cycling race with just five days' notice. I accepted, and it reignited my fire. I joined a local triathlon club with a single goal: to become an Olympian.
22 yrs old: Made it onto the national triathlon team, traveling the world and competing at the highest level.
24 yrs old: Won the AG European Championships in Sprint Triathlon (Geneva) while earning my Bachelor’s in Sports Science. Became head coach for my local triathlon youth club and started studying physiotherapy to understand sports injuries better.
25 yrs old: Founded my own company specializing in talent development and running form analysis. I wanted to use my knowledge to help others achieve top performances while funding my career.
26 yrs old: Won my second AG European Championship in Sprint Triathlon (Düsseldorf).
27 yrs old: Finished 5th at the Elite World Championships (Aquathlon) and 9th at the Elite World Championships (Duathlon). Joined the national Olympic training squad for Tokyo 2020 and became a certified physiotherapist.
28 yrs old: Became a sports physiotherapist and worked as a physiotherapist for a professional football club.
30 yrs old: After 5 national championship titles and a decade as a top-level triathlete I became a dad and retired from professional triathlon.
31 yrs old: Quit my job as a physiotherapist and became a full-time elite performance coach for up-and-coming talents and professional athletes. My first athlete I've been training for 5+ yrs became a World Champion.
32 yrs old: Launched this YouTube channel to make world-class performance principles accessible to everyone.
33 yrs old: Celebrated my first athlete qualifying for the Olympics.

Today: I’m working with world-class athletes, sports organizations, and some of the largest entities in Danish elite sports, including Team Denmark. My main job is to quantify and distill world-class performance into principles that create the best talent environments in the world.

To all of you seeking more. Every setback is a lesson, every victory a step forward.

The tougher the enemy, the greater the victory.

You either conquer the fight or become stronger for the next one. Both mean you win.

Keep fighting. May your willpower hit harder than your fears.

Never back down,

Nicklas

Disclaimers: Nicklas Røssner is not a doctor or a medical professional. Always consult a physician before starting any exercise program. Use this information strictly at your own risk. Nicklas Røssner will not assume any liability for direct or indirect losses or damages that may result from the use of information contained in this video included but not limited to economic loss, ilness, injury or death.

[NicklasRossnerPT]

References:

Rodrigo-Carranza V, González-Mohíno F, Santos-Concejero J, González-Ravé JM. Influence of Shoe Mass on Performance and Running Economy in Trained Runners. Front Physiol. 2020

Haugen T, Sandbakk Ø, Seiler S, Tønnessen E. The Training Characteristics of World-Class Distance Runners: An Integration of Scientific Literature and Results-Proven Practice. Sports Med Open. 2022

Rosenblat MA, Watt JA, Arnold JI, Treff G, Sandbakk ØB, Esteve-Lanao J, Festa L, Filipas L, Galloway SD, Muñoz I, Ramos-Campo DJ, Schneeweiss P, Sellés-Pérez S, Stöggl T, Talsnes RK, Zinner C, Seiler S. Which Training Intensity Distribution Intervention will Produce the Greatest Improvements in Maximal Oxygen Uptake and Time-Trial Performance in Endurance Athletes? A Systematic Review and Network Meta-analysis of Individual Participant Data. Sports Med. 2025

Silva Oliveira P, Boppre G, Fonseca H. Comparison of Polarized Versus Other Types of Endurance Training Intensity Distribution on Athletes' Endurance Performance: A Systematic Review with Meta-analysis. Sports Med. 2024

Blondel, Nicolas & Berthoin, Serge & Billat, Veronique & Lensel, Ghislaine. (2001). Relationship Between Run Times to Exhaustion at 90, 100, 120, and 140 % of vV˙O2max and Velocity Expressed Relatively to Critical Velocity and Maximal Velocity. International journal of sports medicine.

Effects of Strength Training on Running Economy in Highly Trained Runners: A Systematic Review with Meta-Analysis of Controlled Trials” by Ardigò et al. (2020)

Pryor, J Luke & Johnson, Evan & Yoder, Hillary & Looney, David. (2019). Keeping Pace: A Practitioner-Focused Review of Pacing Strategies in Running. Strength and Conditioning Journal. 42.

Jiang X, Xu D, Fang Y, Bíró I, Baker JS, Gu Y. PCA of Running Biomechanics after 5 km between Novice and Experienced Runners. Bioengineering. 2023

Casa DJ, Armstrong LE, Hillman SK, Montain SJ, Reiff RV, Rich BS, Roberts WO, Stone JA. National athletic trainers' association position statement: fluid replacement for athletes. J Athl Train. 2000

Goulet ED. Dehydration and endurance performance in competitive athletes. Nutr Rev. 2012

Sawka, M. N., Burke, L. M., Eichner, E. R., Maughan, R. J., Montain, S. J., & Stachenfeld, N. S. (2007). "American College of Sports Medicine position stand: Exercise and fluid replacement." Medicine & Science in Sports & Exercise, 39(2), 377-390.

Burke LM, Hawley JA, Wong SH, Jeukendrup AE. Carbohydrates for training and competition. J Sports Sci. 2011;29

Kanter M. High-Quality Carbohydrates and Physical Performance: Expert Panel Report. Nutr Today. 2018

[calisthenicswBin]

Honestly the best running advice on youtube is on your channel, thanks a lot for the free program! hope you hit 100k soon

[knlok]

HI Nicklas, Regarding the polarized model, you and I are on the same page. A well-known physiologist said "normal athletes should train like elite athletes". Which means 20% anaerobic. However, slower runners will only get anaerobic (perhaps close to their LT)in the final 1-minute sprint. So, spending 20% of their training in the anaerobic zone is way overdone. Even more: it will be at the expense of more effective aerobic sessions. For well-trained slower runners, just a few anaerobic tempos in the final 3 weeks before a peak race could be beneficial. Cheers!

[clifflocklear]

Thanks for this video! You break down a lot of different categories that most videos don’t. It’s much appreciated!

[andrewmatthews]

Absolutely love the tempo of your videos. High quality information compressed well. One of the few channels I watch at normal speed 😆

[goodyeoman]

It's useful to break things up into strength, speed, and endurance. Some people have weak legs so struggle to kick on in the last K, others don't have the cardio to maintain a modest pace, and some lack the leg turnover needed for speed. Whichever one you think you're weak in, prioritise your training around. For me it was speed.

[ross_cruickshank]

As very much a "recreational" runner I have always enjoyed trying to negative split, many of us feel a feeling of a complisment if we can finish strong even if the time is 25+ minutes. However, my local parkrun has a downhill start which means an uphill finish so I have had learn to live with that.

[nicodemusjansson]

Thanks for the very informative video! Would love to see the same take on a 10k race. Especially the pacing would be of interest.

[KhattaRapidus]

Run the speed you're trying to reach and in shorter distance, separately from your main running. Train swimming for heart cardio, don't skip meals, and buy quality proven supplements/vitamins, not cheap garbage. I go by a car speedometer app for incremental improvements in my 5k. So I build into the distance and it seems to work. Just over a year. I have gone from 10-15 minute miles to 7-8 minutes miles. My best 5k so far has been 9mph. I'm working on working up to 10mph 5k.

[weuek]

My problem is that I simply like running. That's why a plan is not for me as there is not enough running in it.

[hardiklavanshi]

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[Me-cass]

Følger dig ! Og fedt at se en dansker på YT der laver god youtube og præcis information!

[AstoriaRunner]

Good video, thank you 😊
Do you have a similar video for running faster marathons?

[broken__rox]

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[Marathon]

I would say for the electrolytes, it’s highly personal what each person needs and they need to experiment. I eat a low sodium diet and don’t add much sodium for my hard/long runs. I never get cramps and my performance is not impacted. My potassium intake is a lot higher, about 8-10k mg vs sodium of under 2k mg.

[SahilKale-zu]

Bro thanks a lot for just giving me what I want!
But I have a request!😅
I can run 18-19 min 5km and I want a daily schedule which can improve my running fast, no matter how hard the running schedule is! Look I am not impatient and I know recovery is also important so I am asking you. So could you please 🥺 make a schedule like that.

[Howwhen_IQof]

I used to always let everyone pass me in the first 800m, the catch them back in the next 2400m, and the last 1600....pure death. And I get near perfect pacing every race

[surajsinghrajput]

I tried everything, preworkouts, youtube gurus, morning routines that nearly killed me. none of it hit. then i saw someone mention Testosterone Rewired by David Brooks in the comments and it literally changed my life. Following everything in that book past couple of weeks made me realize I was running on empty for YEARS. wish I knew about this years ago🔥

[Raucherbeinknacker]

Training with heavy shoes or some small ankle weights can teach you to move your feet in the most economic way also!

[bugfubugfu]

All these are cool and nice if i was able to follow them. There's so many guides for runners on the internet every small detail is mentioned but for most people we are not pro runners, we run as a hobby because we like it and it doesn't make sense to stress over all these because for example i work night shifts, long hours, extra hours... And just one night shift followed by a day where you have other stuff to take care of and then work again... I cannot focus that much on this even if i did one night shift is enough to set me back in my progress so now i just run when i can not having any specific goal cuz it's not realistic for me. I mean all of us have huge potentials to achieve phenomenal results but it's just not something that our path in life leads to. Life gets in the way and running isn't what pays my bills it's a hobby so it doesn't make sense to focus so much on it, over time you even lose interest cuz you feel like you're not progressing, doing the same thing over and over again... Yeah idk