Marathon Mondays: Using Lactate Threshold to Improve Performance
With 15 full weeks to go until the SSE Dublin Marathon kicks off at 9:00am we have decided to try and help you on your way towards that looming goal.
15 weeks is more than enough time to fine-tune preparations, log the miles, buy the unnecessary water belts and sweat bands and get yourself ready for Marathon Madness on the 26th of October.
Firstly we are going to look into the idea of Lactate. We spoke to Emmett Dunleavy of PerfectingPacing.com about what Lactate is and what can be done to master it to improve performance. Emmet Dunleavy (Sligo AC) has won 5 National senior track medals as well as National Novice and National Intermediate cross country titles. He has represented Ireland on a number of occasions and once dead-heated with Mo Farah in a Parkrun but he doesn’t like to talk about it.
What is Lactate / Lactic Acid?
Science hats on for a second. Lactate is an output of the anaerobic system. Essentially as the intensity of an exercise increases, the level of lactate in the blood will rise. When blood lactate readings increase, the duration of the exercise becomes less sustainable.
The point at which the production of lactate is faster than lactate clearance is called the lactate threshold. It is also sometimes referred to as the anaerobic threshold, but not for the purposes of this article.
Contrary to popular opinion, lactate itself is not the enemy of the athlete. Lactate is actually used as a fuel by the body, especially at the lower levels of intensity. The processes that occur in conjunction with lactate production are the real enemy. However they are not measurable, but they do occur at the same rate, therefore blood lactate becomes the barometer for fatigue. It is blood lactate that provides an insight to the sustainability of a given pace or level of heart rate.
The terms lactate and lactic acid are often used interchangeably. This is technically incorrect as lactic acid is very swiftly broken down into lactate and hydrogen ions. The increase in hydrogen ions and other by-products rather than lactate, leads to acidosis of the muscle and as a result has a negative impact on performance.
In a nutshell, the level of lactate is what the athlete or coach is interested in. The higher the lactate reading, the shorter the duration of exercise.
Examples of lactate readings below. (These are very much general guidelines and vary by athlete)
How does it affect performance?
The ability to deal with lactate is a major limiting factor when running.
At rest and at low levels of intensity (jogging pace), athletes have the ability to clear the amount of lactate being produced within the body.
However, as the intensity rises, so does the reading of blood lactate as lactate is being produced faster than the body can clear it. The good news is that an athlete can increase their lactate threshold through adaptations made during proper endurance training. The goal of training is to teach the body to clear the lactate allowing the athlete to sustain a given pace for longer.
By enhancing lactate tolerance (via hard short intervals) and lactate threshold (via tempo’s) the middle distance athlete can improve performance.
For marathon runners, improving the aerobic threshold (in addition to endurance, fat burning etc.) will lead to faster race times.
How can we test our current levels?
A lactate test identifies the training sweet spot and is a powerful tool for endurance athletes. Runners can then train at the most beneficial heart rate or pace – a pace or heart rate that is completely individual to each runner, based on current ability and the target event or fitness goal.
The test results will pinpoint various training paces and heart rates that are specific to the individual. Additionally, the test provides an insight to the athlete’s profile. Suggesting whether the runner has predominantly fast twitch or slow twitch fibres. This has a significant influence of the training volume and intensity.
There are a number of methods available to measure lactate
1) Step Test
The traditional method of lactate testing is a step test where the athletes complete a series of intervals at a gradually increasing pace or heart rate.
The traditional lab test is performed on a treadmill. The athlete starts out at an easy jog and the pace of the treadmill increases every 3 minutes. At each 3 minute interval, a blood lactate reading is taken from the finger or ear lobe. Heart rate is also noted at each stage. The test continues until blood lactate begins to rise exponentially.
Similarly, this test can be conducted outdoors on a running track. Outdoor tests tend to have longer duration (5-6 minute intervals) but a reduced number of intervals. Again after each interval, blood lactate is measured and heartrate recorded.
2) Calf Sleeve Test
A new product to the market is the BSX Insight. This is a sleeve worn on the calf. The sleeve contains technology that can non-invasively measure the level of lactate in the blood as it passes through the calf. It does this in real time and sends the data via ANT to a watch or wrist device.
While this technology is in its early stages, it is most likely only a matter of time before the device becomes widely available. In the same way many athletes currently wear heart rate monitors, lactate analysers may soon become part of your kit for everyday training.
3) Threshold Estimates
For anyone not in a position to test lactate levels, there is a procedure for estimating thresholds.
We know that lactate threshold pace is sustainable for approximately 1 hour in a race situation.
By taking a recent race performance and plugging it into a running calculator (e.g www.McMillanrunning.com) an approximation can be made of what pace is sustainable for 1 hour.
Take someone who has run 20 minutes for 5k. Putting that time into McMillan, this athlete can run 15km in 64 minutes. Therefore the athlete can sustain 6.54 per mile for 1 hour. This is a best guess of lactate threshold pace.
Aerobic pace can be taken as marathon pace. Again using our 20 minute 5k runner as an example, McMillan suggests a marathon pace of 7.26 per mile.
To get corresponding heart rates for these paces, go to a running track and after an easy warmup, complete 5-10 minutes running at each of the above paces. The HR over the final stages at each pace will be the approximate aerobic and lactate threshold heart rates.
It should be noted that these are very much rough estimates and a full test is required for accurate results.
What can we do to improve lactate threshold?
Improving the threshold paces is one of the primary goals of training. The optimum method of improving threshold pace is to work at the pace and /or heart rate just below the lactate threshold. Over time this will have the effect of raising the pace at which the lactate threshold occurs.
Workouts used to improve threshold range from 3-10 minute intervals, to the traditional tempo run of 20-25 minutes. The lactate threshold effort level is one that can be sustained in a race situation for 1 hour. It is a comfortably hard effort and should register a 7-8 out of 10 on a perceived effort scale.
A good rule of thumb for training – tempo runs at the lactate threshold should not exceed 25 minutes and split threshold runs (i.e intervals) should not exceed 35 minutes.
It should be noted that heart rate is a much better guide than pace during training. Heart rate will take into account the recent training load, current fatigue, terrain and weather. Sticking rigidly to a given pace established on test day (under optimum conditions) is not a reliable gauge when training in the field.
How does this tie in with tempo runs?
There are a variety of different types of tempo runs depending on the athlete and the event being prepared for. Marathon runners will do longer steady tempos of up to an hour at approximately the aerobic threshold. 800/1500m athletes may do tempo runs as short as 8-10 minutes, as it is more specific to their event.
The traditional 20-25 minute tempo run for middle distance, road and cross country runners is most popular amongst athletes and coaches. As explained previously, the tempo run should be performed just below the lactate threshold heart rate.
Finally, it’s worth keeping in mind that while lactates and threshold training are a valuable tool for distance athletes, they are by no means a magic bullet providing instant results.A well rounded schedule needs to contain threshold work, speed development, strength development, endurance training and race-specific workouts in order to reap full benefits.
Of vital importance is training each facet of the event requirements, right throughout the season. The emphasis on each of the various components should change as the season progresses, requiring a periodised and well planned training schedule. Rather like baking a cake, all of the training ingredients need to be present. Finding the exact ratio of ingredients for individual athletes may take some trial and error.