Constructing Speed Sessions
Any speed workout has 6 variables and the manipulation of these variables can change the workout from a VO2 max session to a tempo session. Understanding these variables and their relationship with each other is fundamental to designing speed sessions to suit the athlete and the training phase.
The six variables are
Interval Duration/ Distance
Recovery Duration/ Distance.
Number of reps
Interval Intensity
Recovery Intensity
Total Duration at Intensity
Lets look at a few examples to understand each of these
Example 1
8 x 1km at Threshold with 90 seconds walk jog recovery
Interval Duration/ Distance 1km
Recovery Duration/ Distance 90 seconds
Number of reps 8
Interval Intensity Threshold
Recovery Intensity very easy
Total Duration at Intensity 8km
Example 2
10 x 90 seconds at 110% of Threshold with 60 seconds walk jog recovery
Interval Duration/ Distance 90 seconds
Recovery Duration/ Distance 60 seconds
Number of reps 10
Interval Intensity 110% of Threshold
Recovery Intensity very easy
Total Duration at Intensity 15 minutes
Now lets look at how two very similar looking sessions can be very different workouts just by changing one or two of those variables
The session is
6 x 3 minutes, 3 minutes recovery
So we have Interval Duration ,Recovery Duration , Number of Reps and Duration at Intensity are all the same
BUT if one workout has a interval intensity of VO2 max and the recovery intensity is walking and the other workout is run at Threshold intensity with recovery intensity of Marathon pace you can see they are vastly different workouts
One is extremely hard ( 6 x 3 minutes at VO2 max intensity ) the other is relatively easy – ie 36 minutes alternating between 3 minutes threshold 3 minutes marathon pace.
When prescribing intervals make sure you are specific in all 6 variables to ensure your athlete is running the session at the correct intensity.
We will talk about how to manipulate these variables to elicit different training responses in the next few lessons on speed.
What happens if we get one or two of these variables incorrect?
It is likely the session will either be too easy or impossible to complete.
Eg if you prescribe 6 x 3 minutes at 115% of threshold but with only 1 minutes recovery then it’s extremely unlikely the athlete will be able to perform more than a few reps at the specified intensity.
Constructing a speed session to ensure the athlete can complete the session at the right intensity is a key skill of a coach. We need to have a good understanding of our athletes abilities rather than trying to use a standardised prescription.
Relationship between the variables
Some of the 6 variables have a very direct relationship but others have a more nuanced relationship. Let’s look at how they relate to each other.
Total Duration at Intensity – Interval Intensity – recovery period
These three are the most closely connected. The duration at intensity, how long the recovery period is and the intensity of recovery are the major influences on what intensity the intervals can be run at
Eg if duration at intensity is 30 minutes ( eg 6 x 5 minutes ) and you want to target 5k pace ( and for sake of this example lets say thats 4 min ks ) then its going to be an extremely challenging almost impossible session unless you have long recovery periods.
Eg 6 x 5 minutes with 1 minutes recovery at this athletes 5k pace is not likely possible. We are asking them to run 30 minutes at a pace they can only hold for 20 minutes. Even with it broken up into 5-minute intervals the recovery period is not long enough to allow them to maintain the pace.
However 6 x 5 minutes with 3 minutes recovery might be possible at this athletes 5k pace .The longer recovery period will go a long way to allow the athlete to keep the pace up – wont be easy but possible.
As a general rule – if you start with whatever pace the athlete can maintain in a non stop run on fresh legs then they can do the same duration on training legs with short recovery periods. Once you start increasing duration or intensity ,longer recovery is needed. Here is an example which might help make sense of it.
If an athlete can run 5km in 20 minutes in a race on fresh legs – ie 4 min k pace Then in training on tired legs a session of 5 x 4 minutes @ 4 min k pace with 60 seconds is possible.
If we either increase the pace OR increase the total duration we need to increase recovery period
Eg If we increase the pace to 3:50 min ks then we likely need to increase the ry period to 90 seconds or more to enable the athlete to complete a 5 x 4 mins session or
If we add an extra rep we also probably need to increase the recovery period eg
6 x 4 minutes @ 4 min ks with 90 seconds recovery
Interval Duration vs Interval Intensity
Does the length of our intervals affect the intensity at which they are run ?
For example is there any difference between a session of 5 x 5 minutes with 2 minutes recovery vs 10 x 2:30 with 1 minutes recovery both targeting same intensity ?
The first session takes 33 minutes the second takes 34 minutes ( if you dont include the final recovery period given the session is finished at that point )
Both sessions have same Duration at intensity and same interval intensity and take very close to the same overall time. So is there any difference ?
You might argue no but it really does depend on the athlete . If the athlete had been doing short intervals of 1-3 minutes for a period of time then possibly increasing it to 5 minutes they may find that more physically and or mentally challenging than usual . But this is very athlete dependant – some may even find longer intervals easier than shorter ones.
I have some athletes that struggle with longer reps but can hold intensity for same overall duration if using shorter reps. The question then to ask yourself is what the athlete will benefit most from – sticking with shorter reps and building duration or intensity or changing to longer reps and see if they can adapt.
One method for increasing duration is adjusting the recovery period.
Using the above example we can progress as follows
1. 10 x 2:30 with 60 seconds recovery
2. 2 x 2:30 with 30 seconds recovery then 2 minutes recovery then repeat for 5 sets .
3. 5 x 5 minutes with 3 minutes recovery
4. 5 x 5 minutes with 2 minutes recovery
In this case the first step was breaking the 5 min reps into 2 halves with a 30 second recovery between
The second step we ran the whole 5 minutes but increased the recovery before finally progressing to the 5 x 5 with 2 minutes recovery
Recovery intensity vs interval intensity
Usually the recovery intensity is very easy – ie a walk or slow jog but as we move into threshold intensity there is a case for making recovery periods a little faster. However if recovery period is faster then we have to lower our interval intensity
For example
Using a 20 minutes park runner
5 x 5 minutes at 5k pace with 2 minutes recovery at walk jog pace
Vs
5 x 5 minutes with 2 minutes recovery at marathon pace
The pace the athlete can hold for the 5 minutes will need to be slower , more like 10k pace for this athlete in order to get through the second session.
How to progress intervals
We can progress one or all of the six variables to make a session harder – all depends on what we are trying to target.
We can work on extending duration – in which case intensity would stay the same but recovery periods may reduce , interval duration may increase and total duration at intensity may increase
Eg if we start with 6 x 4 with 90 seconds recovery at 4min k pace
Then some progressions that target increasing intensity duration might be
5 x 5 minutes with 90 second recovery at 4 min k pace
– here we have increased both the interval duration and total duration at intensity duration
6 x 4 minutes with 60 second recovery at 4 min k pace
– decreasing recovery period makes this session harder than the original session
If we are wanting to increase speed then some progressions might be
8 x 3 minutes with 2 minutes recovery at 3:55min k pace
Shorter interval duration and longer recovery will allow a slightly faster speed to be run
4 x 5 with 2 minutes recovery at 3:55 min k pace
In this example even though the interval duration is longer the total duration at intensity
By making small changes each week we give the body time to adapt hence we can build duration or speed over time.
Should intervals get quicker throughout or be consistent ?
It depends on the athlete and the workout . I will typically advise less experienced athletes or athletes in early phase of training to start slower and build throughout the session with the last few reps the fastest.
Later in the training phase consistency would be the goal.
Is it better to prescribe by distance or time ?
Sessions are often given in terms of distance – eg 8 x 1km or 5 x 1 mile but one has to be careful with the idea that a session has the same relative intensity for all athletes.
For example 8 x 1km might mean 24 minutes or less of hard running for an elite and 40 minutes or more for a mid to back pack runner. The intensity will be significantly lower for the slower runner compared to the faster runner.
But if you use 8 x 3 minutes then regardless whether you are elite or back of the pack it will be the same relative intensity.
One could still argue that a very fit elite athlete could hold a higher relative intensity for a specific duration compared to a less fit athlete but the difference is significantly less than if using distance to determine the intervals.
So be very mindful of seeing suggested speed sessions in a program based on distance and applying them uniformly to athletes of different abilities
Should you push to failure ?
There is very little if any research to argue that going to your absolute limit in speed sessions offers any advantages over finishing sessions with a little bit left in the tank. Due to the increased injury risks and extra fatigue I rarely recommend pushing 100%. Maybe once or twice in a training phase for some athletes and more as a mental test than a physical one .
How fast should the recovery interval be ?
The purpose of the recovery interval is to recover so for most sessions a walk or very slow jog is 100% ok . I see too many athletes running the recovery periods too fast which just compromises how fast they are able to run in the work interval.
In some cases the “ recovery “ interval may be at a prescribed pace. For example “under overs” is a session where you go slightly over threshold and then slightly under threshold so the “ recovery “ interval is not really recovery at all. This is more advanced training and for the vast majority of speed sessions a walk or very slow jog in the recovery is an appropriate intensity
Do intervals always have to be at the same intensity. ?
No – some sessions will increase intensity or decrease intensity throughout
Eg as session like 400,800,1200,1600,1200,800,400 with 90 seconds walk recovery you may specify faster speeds for the shorter distances. Keep in mind this will be very challenging for less experienced runners , the slight changes in speed for each distance takes experience to be able to dial in.
Key Take Homes
Interval training sessions are put together using 6 variables
Interval Duration
Recovery Duration
Interval Intensity
Recovery Intensity
Number of Reps
Total duration at intensity
Care needs to be given to all six of these to ensure the appropriate intensity and duration is being targeted.