You Aren't "De-Conditioned". You're Just Not Fast.

Disclaimer: this article is very basic. I’ve broken down the ASR and its surrounding concepts into the most simple, basic form possible. There are more informative, scientifically cited/supported articles online, such as this one, if you prefer big words and hard-to-swallow concepts. We’re just keeping it realistic here!


Of the likely thousands of conversations I’ve had with head sport coaches in my life, one stands out about the rest.

It usually starts with a statement along the lines of “we need to improve our conditioning. The guys are simply not fit and other teams are always outrunning us” or “we can’t keep up after the 70’.”


Let me introduce you to our dear friend, the Anaerobic Speed Reserve.


First of all, let’s break down our themes.

(AYYY freshman biology throwback!!)

Fitness, speed, and conditioning are not the same things and they cannot be used as such.

Fitness is an umbrella term; it encompasses subcategories like Speed, Strength, Condition, Mobility, and other terms.

Conditioning refers to endurance, aerobic capacity, or the ability to work over a long period of time.

Speed is SAQ - the ability to move with speed, agility, and quickness.

When talking about the Anaerobic Speed Reserve (ASR), we’re differentiating between SPEED and CONDITIONING.

But, first, let’s cover a few more terms.

Anaerobic is, if you remember that science class you probably didn’t want to go to, short-term energy system. It doesn’t require oxygen to produce energy, and it’s used for short, intense, maximal capacity work. It fuels us for a maximum of (about) 90 seconds. This is what we use when sprinting.

The aerobic system, however, is a long-term system. It uses oxygen to produce energy and fuels the body for everything over approximately 2 minutes. This is what we use when distance running or playing 90’.

Thus, we can conclude that the Anaerobic Speed Reserve requires a short-term energy system.

However, we can also begin to conclude that SPRINTING IS NOT CONDITIONING.

Let’s continue.

The Maximal Sprint Speed (MSS) can be thought of as an athlete’s absolute maximum capacity. It’s their 30m sprint PR, their best 100 time. It’s the absolute 100% top speed.

The Max Aerobic Capacity (MAC), also called your “velocity at maximum oxygen consumption” or (v)Vo2Max, is the maximum speed-endurance an athlete can achieve at the top of his or her Vo2Max. It’s him/her essentially maxing out the aerobic energy system’s contribution to speed across time.

So, to make these big words and complicated systems all make sense…

An example.

Athlete 1 and Athlete 2.

The very top of each column is each player’s MSS (100% capacity). Those lines in between represent each player’s MAS, their velocity at their Vo2Max.

Excellent graphic representing two different athletes  from this article.

Excellent graphic representing two different athletes from this article.

Most importantly, the space between the players’ MSS and MAS is their ASR, their speed reserve.

Again, the begging question:

WHY does Speed matter over Conditioning?

Back to the graphic, see where the figure says “HIT Running Speed”?

Which of the two athletes represented here do you think has to work harder to maintain that HIT Running Speed?

Athlete A, right?

Although both athletes have the same MAS, their MSS is different. That means that the athlete with the higher/fast Maximal Sprint Speed, and, thus, the bigger ASR, is going to have less of an issue reaching and maintaining that pace for a longer period of time as athletes with a lower MSS and less ASR.

Let’s put this in a soccer-specific context, huh?

Imagine, instead of Athletes A & B, we’re got Teams A & B.

Team A sprints. A lot! Their average MSS is 30km/hr.

Team B sprints a bit but conditions a lot. Their average MSS is 25km/hr.

If the average game speed is 21km/hr, which team will play a fast 90’? Which team will absolutely dominate and set the tempo? Which team will be wiped after the match?

Team B. Because their average ASR is significantly smaller than Team A’s.


Although we generally (mistakenly) group speed and conditioning together, our athletes often lack speed, not general fitness or condition.

The ability to run distance is great. Important for court and field sports, especially soccer!

However, the ability to run fast is often what we lack!


Because, with a higher Maximal Sprint Speed and a greater Anaerobic Speed Reserve, athletes can run at 60-80% (around their velocity at Vo2Max) faster for longer than athletes with lower MSS and less ASR.

Higher MSS and bigger ASRs save energy and buy tempo.

Again, conditioning is vital.

But the team who can run moderately fast for 90’ will get absolutely annihilated by a team who can keep a submaximal sprint for 90’. Every time.

And that’s where speed science wins.

(For more information on speed and how to realistically implement it into training/concepts, I recommend visiting the works of Charlie Francis, Dan Pfaff, Henk Kraaijenhof, Derek Hansen, & Hunter Charneski. Or just ask!)