Anaerobic speed reserve (ASR), also referred to as ‘anaerobic velocity reserve (AVR)’ is the difference between an athlete’s maximum sprint speed and their maximal aerobic speed (Sandford et al., 2021).

Imagine an aerobically fit athlete with a high maximal sprinting speed - they are likely to be able to perform more high-intensity actions and be involved in more game impacting moments. On the flip side, aerobically unfit athletes with a slow top speed will struggle to compete with them.

Relationship to sports performance

A couple of key take homes from existing research on this area are as follows:

• Athletes with a greater ASR show lower neuromuscular impairments and RPE during high intensity interval work (Bucheit and Laursen, 2013). This makes sense, as athletes with a higher ASR will find each interval less physically demanding, and therefore it will be less costly per effort. 
  


• Time to exhaustion is more accurately predicted by % ASR and not % MAS in events up to 8 minutes in duration (88% of the variance explained by ASR workload %) (Blondel et al., 2001). In other words, in sports lasting less than 8 minutes, anaerobic capacity is a bigger contributor to physiological fatigue. In hockey terms, players often complete 8 minute rotations, and therefore it’s important to consider the impact of a larger ASR on running performance in intermittent efforts like this. 
  


• ASR is a bigger determinant of 800m running performance at the elite level, compared with sub-elite runners (Ingham et al., 2008; Sandford et al., 2019). At the sub-elite level, a larger MAS score has a larger impact on performance. At the elite level, ASR is a much bigger determinant of performance. 
  

Impact on hockey running performance

Given that a higher ASR is associated with increased running performance at the elite level, we can infer that increasing it may have an impact on hockey running performance. This would make logical sense, given that hockey is a repeat-sprint based sport with a large anaerobic requirement.

Imagine for a moment that an athlete has a maximal aerobic speed (MAS) score of 4m/s and a maximal sprint speed (MSS) of 8m/s. This would give an ASR of 4m/s (MSS - MAS = ASR).

Running at 5m/s would represent 25% of their ASR.

However, if that hockey player increases their MSS to 9m/s, running at 5m/s now represents just 20% of their ASR. Their running economy has now improved, and each running effort above 5m/s (18kph) is less costly.

By not increasing the athlete’s aerobic fitness, their running capabilities have still improved. It is feasible that they would be able to therefore produce more high-intensity actions and recover faster between efforts. This is of course an inference not based on objective reality but would make a lot of sense based on the research already outlined.

Assessing the anaerobic speed reserve (ASR)

Determining ASR is actually very simple, although not always easy. This is because unless you have timing gates, measuring top sprint speed is a little tricky and unreliable.

You only need to measure two things to establish ASR:

• Maximal aerobic speed (MAS)


• Maximal sprint speed (MSS)

To measure MAS the simplest and most cost-effective means of doing so is to complete a 16 pitch lengths (1462m) test. You can read more about measuring MAS in my article here.

For example, if the athlete runs 1462m in 365 seconds (6:05 minutes), then your MAS score is 4m/s (1462 ÷ 365).

To measure MSS, you will need to set up a flying 30-40m split time sprint. Set up two timing gates, one at 30m, and one at 40m. Athletes sprint as fast as they can from the 0m line through to the 40m line, and their split time from 30-40m is taken as their MSS.

For example, if the athlete runs this distance in 1.25 seconds, then their MSS is 8m/s (10 ÷ 1.25).

To measure ASR, simply minus MAS from MSS to get your score in m/s. In this case, 8m/s - 4m/s = 4m/s.

Why measure and prescribe ASR?

You may be wondering why the need to measure sprint speed as well as aerobic speed - why not just pick one? The simple answer is that there is more precision in prescription when both numbers are included. By taking into consideration an athlete’s anaerobic as well as aerobic capabilities, physiological responses (and therefore adaptations) are more consistent. This means that we are more likely to achieve the intended outcomes that we want from training.

If we only prescribe from MAS, then some athletes may be working much harder than others with all else being equal. Imagine two athletes A and B with the same MAS score of 4m/s, but Athlete A has a MSS of 8m/s and Athlete B has a MSS of 9m/s. Going back to the earlier example, who is working harder at 120% MAS? Athlete A is working at 20% ASR, but Athlete B is only working at 16% ASR.

By only prescribing from MAS alone, although seemingly the same intensity for both, Athlete A would be working harder. This is the value of considering anaerobic capabilities too.

This is supported by research. Julio et al. (2020) found that there was less inter-athlete variability in lactate scores and time to exhaustion in rugby players and long-distance runners when prescribing from ASR compared with MAS. In other words, by taking into consideration anaerobic capabilities, physiological responses were kept consistent across a group of endurance and team sport athletes.

From a hockey perspective, this means that a squad of players will respond in a more uniform manner to conditioning prescription when ASR is used as the reference point and not just MAS.

Determining locomotor profile from ASR

Sandford et al. (2021) made the suggestion that by determining an athlete’s locomotor profile, conditioning sessions can be more individualized. They categorised this into three groups: speed profile, endurance profile and hybrid profile.

• A speed profile is a fast-twitch dominant athlete with a relatively low MAS score and a high maximal sprint speed. This means that they have a large ASR. They are suited to shorter, more intensive conditioning sessions.


• An endurance profile is a slow-twitch dominant athlete with a relatively high MAS score and a low maximal sprint speed. This means that they have a small ASR. They are suited to longer, more extensive conditioning sessions.


• A hybrid profile is a blend of the two profiles above, with a moderate MAS and maximal sprint speed score. 

Prescribing conditioning sessions from ASR

Now that we know how to assess ASR, we can prescribe from it.

For the sake of clarity, let’s imagine that an athlete has a MAS score of 4.5m/s and a MSS of 8.5m/s. Their ASR is therefore 4m/s.

To work out the running prescription based on ASR, you simply need to work out the relevant percentage of the ASR and then add it to MAS. E.g. in this case, 10% of ASR is 4.9m/s for the athlete.

• ASR = 4m/s


• 10% = 0.4m/s


• 0.4m/s + 4.5m/s = 4.9m/s

Below are two simple sessions for prescribing high-intensity intervals:

30 seconds on, 30 seconds off @ 10% ASR

E.g. this athlete would have a target distance of 147m in 30 seconds based on their ASR (30 seconds x 4.9m/s = 147m)

15 seconds on, 15 seconds off @ 20% ASR

E.g. this athlete would have a target distance of 80m in 15 seconds based on their ASR (15 seconds x 5.3m/s = 80m)

You could also prescribe intervals at 25% and 50% ASR, however, the higher you go the closer that you are to maximal sprint speed. At this point, it may be simpler to just focus on maximal sprinting as this will contribute to enhancing ASR anyway!