Improving Basic Speed
Your speed is how fast you can run for a short period of time and determines the pace you can attain but not the pace you can maintain.
You can think of speed as your stride frequency multiplied by your stride length. Increase one or both while the other is constant and you run faster.
Running short, fast repetitions will improve not only your basic speed but also your running technique and may improve running economy.
While basic speed training is more important for a 5K than a marathon it has a place whatever your goal distance.
Your stride rate, also known as your cadence, is determined by your muscle’s ratio of fast-twitch to slow-twitch muscle fibers. Distance runners tend to have more slow-twitch (good for endurance) while sprinters have more fast-twitch. Fast-twitch fibers give more power per stride and provide a faster stride frequency.
You cannot increase the proportion of any type of fibers you have (genetics) but you can increase the ability of your muscles and nervous system to work faster and more powerfully.
Your neuromuscular system controls your stride rate. Faster turnover requires practice. Your nervous system activates your muscle fibers and this firing pattern controls how fast you run.
Therefore, by running short, fast repetitions, you provide the stimulus for your nervous system to adapt to running faster.
With more speed work, a faster stride rate feels more natural and takes less effort to maintain. When fast-twitch muscle fibers are regularly activated it allows them to be more readily available during a race, allowing more chance of a fast finish.
Additionally and speaking generally, a higher stride rate means less time spent in the air, the lower you elevate your body mass and the softer you are hitting the ground when landing.
Your stride length is determined by how long your legs are (which you can’t control), the power your legs can generate and flexibility (things you can control).
Short, speed work can improve your:
- Range of motion by dynamically stretching your hamstrings and hip flexors
- Power by improving knee drive and ability to ‘toe-off’
- Co-ordination by getting used to running relaxed at speed
These types of sessions are short and performed with sufficient rest (as they are not designed to improve your cardiovascular performance) and should, therefore, mean lactate levels remain low throughout the workout. This means they shouldn’t interfere with longer, race-specific workouts you have planned.
This is the maximal rate at which you can produce energy aerobically and likely the most important variable in determining performance in the mile to 5K range, as the more energy you can produce in this way, the faster the pace you can maintain.
VO2Max is still important for longer races but takes a backseat to lactate threshold in that regard.
Taking a bit of a closer look, VO2Max is:
The maximal amount of oxygen that your heart can pump to your muscles and that your muscles can then use to make energy.
- Maximal heart rate
- Maximal amount of blood pumped each heartbeat
- Amount of oxygen taken from the blood and used by the muscles
While training obviously impacts how high a VO2Max you have, genetics also plays a role.
Maximal heart rate, for example, is one factor determined by genetics and tends to decrease with age, with cardiovascular training slowing that decrease.
The amount of blood pumped per heartbeat, or the stroke volume, is a variable that can increase with training and believed to be the primary adaptation that improves VO2Max.
The proportion of oxygen in the blood used to produce energy can increase with training as blood flow increases to the working muscles.
This is in addition to:
- Increased in the number of capillaries providing oxygen-rich blood to muscle fibers.
- Increase in the number and size of mitochondria.
- Increased aerobic enzyme activity.
Other general notes about VO2Max
- Expressed relative to body weight
- Women tend to have lower VO2Max values than men
- Training can only improve VO2Max within a genetically determined range.
How to improve VO2Max
As with all fitness training, adaptations occur when the body is provided with a stimulus.
For improving VO2Max, the greatest stimulus is training at intensities at 95 to 100% of current VO2Max.
Intensities faster than VO2Max increasingly use the anaerobic system (which stimulate that to improve).
For a rough guide, VO2Max is an intensity that can be maintained for around 8 – 10 minutes, and 95% of which can be maintained for around 15 minutes.
Therefore, the greatest stimulus to improve VO2Max can be achieved by maintaining your cardiovascular system at 95 – 100% for as long as possible during a workout.
This is done by maximising time in the optimal intensity zone by controlling
- How long your intervals are
Efforts of 2 – 6 minutes typically allow one to accumulate the most time at 95 – 100% of VO2Max.
When starting an interval, oxygen consumption and heart rate take time to increase into the optimal range.
Therefore short intervals, while easier, mean a lower proportion of effective training time.
Intervals that are too long, on the other hand, you will not be able to maintain the optimal intensity for the whole workout.
For example, let’s look at someone doing 10 x 2-minute intervals versus someone doing 5 x 4-minute intervals. Both workouts include 20 minutes of total effort, but both may not be equally effective.
If it takes 1 minute to get into the optimal intensity range, the person doing the 2-minute intervals will only spend 1 minute (50%) of the interval doing effective training, resulting in a total of 10 minutes spent at around VO2Max.
The person doing 4-minute intervals will spend 3 minutes (75%) of the interval doing effective training, however, resulting in a total of 15 minutes spent at around VO2Max, culminating in a much more effective workout.
- How many intervals you do
In other words, the amount of total effort for the session. The optimal training volume depends on one’s training history. The key is providing a strong enough stimulus to incur adaptations but not wearing yourself so much that you cannot maintain the right intensity for the current session and/or that you cannot recover quickly enough for your next session or training period.
- How much recovery there is between efforts
The purpose of a recovery between efforts is to allow completion of the session at the required intensity.
If recoveries are too short, you may have to go slower than required or having to cut the workout short because you are worn out.
If recoveries are too long, your heart rate and O2 consumption will decrease so much that it will take too long for them to back into the optimal range during the next interval.
For V02Max work, recoveries tend to typically be 50 – 90% of the length of the effort. Longer efforts need proportionally less rest. For example, a 2-minute effort may need up to 2 minutes of rest, but a 6-minute effort shouldn’t be followed by a rest of more than 3 – 3.5 minutes.
Active or passive recovery?
Research has shown that for endurance running, active recovery is more beneficial. Recovery is increased when you are moving as lactate is removed more quickly, your muscles stay warm and loose and heart rate and O2 consumption is kept elevated allowing them to reach the optimal zone more quickly in the next interval.
If you are too tired to jog or perform an active recovery, then you are most likely running the intervals too hard. While it is not unusual to need to stand or walk for a few seconds after a several minute long effort, you should go into recovery jog as soon as you can.
Designing the workout
As we have seen, an ideal VO2Max workout is one with intervals of 2 – 6 minutes at 95 – 100% of current VO2Max for a total of up to around 10 – 25 minutes of effort.
Some other notes on VO2Max work:
- As well as on a track, VO2Max sessions can be done on roads and trails and can be effective on flats, uphill or on undulating terrain.
- Intervals can be constant, which make it easy to see if you can maintain the optimal intensity with consistency, or varied, to make the workout a bit more interesting.
- Uphill VO2Max work can be useful earlier in a training period when cardiovascular fitness is more useful than pure racing speed.
- Running uphill and then maintaining intensity on a flat or downhill is useful for simulating race conditions and converting uphill power into speed.
Lactate Threshold Training
Lactate is produced in the muscles when carbohydrate is metabolised and is also used by muscles as fuel.
When you walk or run slowly, lactate levels will remain low as the rate of production is equal to the rate of use.
During easy running, the rate of production and the rate of use increase.
Eventually, however, you will reach an effort where the rate of lactate production is greater than the rate of use, causing the concentration of lactate in the muscles and blood to rise.
This is your lactate threshold pace, the intensity at which lactate clearance cannot keep up with production.
Lactate threshold improvements occur when adaptations in muscle fibers allow for decreased lactate production and increased lactate clearance.
While exercise physiologists debate its physiological significance, lactate threshold (LT) pace is often the single best predictor of race pace for distances of 5 miles through the half marathon.
Producing and using lactate
There are much more scientific explanations out there if you want them, but here is a very short summary.
Lactate is formed in the metabolism of carbohydrate. When carbohydrate is broken down to produce energy, an acid called pyruvate is formed.
This acid is used either to
- produce energy aerobically in the mitochondria or
- converted to produce lactate (the salt of lactic acid)
The rate at which lactic acid is formed is the relative rate of pyruvate production to its use by the mitochondria.
A key limiting factor is whether there are enough aerobic enzymes and enough oxygen in the mitochondria to use the pyruvate as fast as its made. If there is too much then lactic acid is formed.
This results in a process that reduces pH levels. This, in turn, is believed to inactivate enzymes and therefore limit energy production. Calcium intake may also take a hit, reducing the muscles’ ability to contract, thus making it difficult to maintain a faster than LT pace for too long.
During exercise, much of the lactate produced is converted back to pyruvate and oxidised to produce energy aerobically within muscles. Lactate also diffuses out of muscles and into the blood.
Lactate can also move in, out and between cells with the help of specific proteins. The increase in the making of these proteins is believed to be a key adaptation that improves LT.
Your lactate threshold pace
Your LT pace is determined by:
- Your oxygen consumption at lactate threshold
This is your level of oxygen used to produce the energy to run at that pace.
- Your running economy
How fast you can run using this amount of oxygen
Lactate threshold can be improved after gains in VO2Max have been maximised. This means that running performance, especially over longer distances, can be still be improved over the years and with age.
While LT is best measured in a lab while taking blood samples during exercise, a low-tech method is to use an estimate of the best pace you could hold for an hour.
Improving Lactate Threshold
For a long time, it was thought that training at LT pace was the best way to improve LT, but increased understanding of physiology has led to updated approaches on how to best improve LT.
These approaches are; training slightly faster than LT pace; mixing harder efforts with efforts slightly slower than LT pace.
These approaches are thought to provide a greater stimulus than training at LT pace to incur the adaptations in the muscle fibers that lead to improvements in LT pace.
Broadly speaking, LT training can be split into four main types:
- Tempo runs
- Change-of-pace tempo runs
- LT, or cruise, intervals
- LT hills
LT should feel comfortably hard. The more time spent at the proper intensity, the greater the training stimulus. Workouts should be challenging but intensity should be at levels one can sustain.
Feeling sore and stiff the day after an LT workout implies one has run too hard.
Classic tempo runs
A continuous run of 20 to 40 minutes, run at a pace that is between LT and slightly faster than LT pace. If you are not used to these kinds of runs it is a good idea to do them on flat routes so intensity and pace can be more easily gauged and maintained. After a few tempo runs you should have developed a feel for the right intensity and effort.
Additionally, low-significance 5K to 10K races are good substitutes for tempo runs as long as one does not get carried away.
Change-of-pace tempo runs
A slightly newer approach to LT training, these involve mixing harder efforts with running at slightly slower than LT pace.
The rationale is that the faster running increases lactate production but the slightly slower pace improves the body’s ability to use that lactate as fuel.
For these workouts, the first faster interval should be at least four minutes long for that initial increase in lactate levels.
Instead of a continuous tempo run, it is believed similar benefits can be gained by breaking the session into several intervals.
Just like in a tempo run, these intervals are run at slightly faster than LT pace. Recoveries between efforts are kept relatively short.
LT intervals can add variety to training and can allow you to spend more time near LT within one workout. They are also great if you tend to avoid classic tempo runs.
The continuous tempo run does have one advantage however in that it is a tough mental workout as well as a physical one, allowing you to practice the mental fortitude required during races.
Each type of training prepares you specifically for the different types of physical challenges you will face during a race. We all have commitments and priorities outside of running so structuring training to make the most of your limited time requires balancing these types of workout to appropriately prepare for the demands of your goal event.
Generally speaking, all the types of workout described above will provide a benefit to performance across any distance of race.
Optimising performance for a specific distance of race will require more race-specific workouts however, as will performing said workouts closer to the goal event.
5K – 10K races will require more VO2Max training, whereas half and full marathon performance will be better aided with more lactate threshold training.
As described in the section regarding basic speed training, loading faster workouts earlier in the training period will result in improvements that will make performing VO2Max intervals easier in the next phase, which in turn will make lactate threshold workouts easier in the subsequent and often final phase of event training.
To conclude, the most important thing to remember is to vary the types of training one does. Performing one type of training consistently can lead to dramatic benefits initially but these improvements will taper off and eventually lead to a plateau in performance. Varying types of training and the stimuli that the body is exposed to is much more likely to result in gradual, continual improvement and increasing specificity towards a goal event will ensure the body is optimally ready for the demands of the race.