GB international Alex Teuten explains how ordinary athletes can gain an edge by undergoing performance testing
This article was written and first published in AW magazine before the coronavirus pandemic.
With the notable exception of the well-documented new midsole technology that now features in many performance shoes, the improvement in times across all running disciplines from 100m to marathon has been almost solely down to knowledge. This is ironic considering one wouldn’t think you need your brain to run!
However, it is our understanding of the body in terms of nutrition, equipment, conditioning and how best to extract every ounce of performance that I believe has led to such drastic advances worldwide. One only needs to look at marathon performances such as Eliud Kipchoge’s sub-two-hour run in Vienna and Brigid Kosgei’s world record in Chicago, to highlight this.
Sports performance testing is very prominent now. For elite athletes it is something akin to commonplace and there are many cut-price options for the brainy runner looking to gain an edge through statistics and knowledge.
The most frequently used laboratory tests for athletes assess the physiological responses to a series of submaximal exercise stages, as well as quantifying the upper limits of an individual’s physiological responses, as assessed during maximal exercise. For runners this test is typically carried out on a treadmill and can be undertaken as two separate tests. That is, a sub maximal test and a maximal test, or as a single, combined test, where after a series of sub maximal exercise stages the runner immediately progresses into the maximal test (without recovery). The advantage of the second approach is that it is more time efficient (for the athlete and the scientist) and has little effect on the data obtained.
A typical submaximal test consists of a series of three to five-minute exercise stages, each separated by a short (30-60sec) recovery period. The speed of the exercise stages is increased after each stage and a 1% gradient is often used to more closely resemble the energy demands of outdoor running. During the last portion of each stage the average heart rate, oxygen uptake, and carbon dioxide production is measured and at the end of the stage a finger-prick blood sample is collected for assessment of blood lactate concentration. The test is normally conducted until the blood lactate concentration exceeds ~4 mmol/L.
At this point the test may be stopped (if undertaking the two tests separately), or immediately progressed into the maximal portion of the test (if undertaking a combined test). Either way during the maximal test the work rate is rapidly increased in a progressive manner until the athlete can no longer maintain pace with the treadmill.
The submaximal test can be used to determine running economy and the speed, heart rate and percentage of VO2 max at which lactate threshold and onset of blood lactate accumulation (OBLA) occur. Lactate threshold is the point at which blood lactate concentration increases beyond the baseline figure and represents the transition from ‘easy’ to ‘steady’ running, or first to second HR zone, if three zones are used. OBLA is defined as the point where blood lactate concentration exceeds 4mmol/L during the test. OBLA is often used as a marker of the transition from ‘steady’ to ‘hard’ exercise, or second to third HR zones.
The VO2 max is determined from the maximal portion of the test and represents the highest rate of oxygen utilisation possible for an individual, or the highest rate of aerobic respiration. It is measured as an absolute value (mL/min), or relative to body mass, mL/min/kg, which takes into account that bigger people are capable of a higher absolute oxygen utilisation and is most relevant for load bearing sports such as running.
One can draw crude comparisons between the data from these tests and the performance of a car. An athlete with a high VO2 max is akin to a powerful car with a large engine. Conversely an economical athlete is analogous to a car that has a good fuel efficiency (or high miles per gallon). An exceptional athlete is one that is both efficient and powerful – in other words they have a good economy and a high VO2 max and lactate threshold. A weakness in any of these areas is always going to present a barrier to achieving top-class performances, although to some extent it is possible to compensate for weakness in one area by excelling in another.
Harnessing the information from these tests can be lucrative for training and racing alike. This type of information can be useful for a variety of reasons ranging from talent identification, benchmarking (relative to own previous data or data from elite athletes), performance prediction, characterising an athlete’s strengths and weaknesses, evaluating the effectiveness of different training interventions and guiding and prescribing training.
From a personal perspective, the most useful data from these tests is the heart rate (HR) zones established in submaximal testing, which can be used to monitor performance during training. Completing appropriate training volumes within the zones can be used to improve performance in a discipline where one would operate at that HR.
In addition, HR gives an indication of health and fitness, as on a particular day an athlete’s HR may be raised due to fatigue or illness, and there is often a systematic decrease in HR over time, both resting and during workouts as the season progresses and
the athlete’s fitness improves.
It is important to undergo the submaximal test regularly, as both running speed and HR will likely correspond to different blood lactate concentrations on subsequent tests and so the training zones will change.
Race results can also be predicted from submaximal tests (and to a lesser extent VO2 max). Various sources suggest a marathon runner will commonly operate around 2mmol blood lactate over a significant part of the race, and so speed at that concentration will correlate to a race time. In addition, the speed at OBLA roughly correlates to 10km race pace.
Another useful analysis from submaximal testing is the relative proportion of energy that the athlete derives from different fuel sources (primarily fats and carbohydrates). These can be calculated from the rate of oxygen uptake and the ratio of carbon dioxide produced to oxygen consumed (respiratory exchange ratio). Put simply, fat metabolism is the main energy source at lower work rates, with a progressive increase in carbohydrate utilisation as the intensity of exercise increases.
This is especially useful for long distance sports such as marathon and ultra-marathon running where the ability to get large amounts of energy from fat efficiently (thereby preventing too quick depletion of carbs) can be beneficial. In addition, a key part of endurance racing is refuelling, and rate of carbohydrate utilisation can be calculated so that fuel strategies can be tailored to the athlete’s energy requirements.
A number of other tests are available such as anthropometry and heat acclimation. The former is an estimation of percentage fat composition through skin-fold measurements, systematically located a fixed distance from a bony landmark. According to
ISAK (International Society for the Advancement of Kinanthropometry) guidelines, it is a better method for estimating body composition than body mass or body mass index, since hydration and muscle mass also contribute to mass. A comparison to athletes of the same ethnicity, age, gender, performance level etc. can be made.
The latter is a useful tool that can assist preparation for a competition in hot conditions such as those frequently encountered in major international events. Similar conditions can be replicated under the safety of a lab environment and through repeated exposure the athlete will adapt to the point where they are better able to tolerate those conditions. It is a key part of optimising performance for these events, where training conditions for British athletes are often dissimilar to those on race day.
Indeed, it is puzzling that athletes often spend so much time training to gain fractional improvements only to neglect to adequately prepare for the environmental conditions that can reduce performance significantly, or worse still result in failure to finish, heat illnesses and in extremely unlikely cases, death. Much of this performance loss and the associated risks to health can be mitigated with appropriate heat acclimation.
» With thanks to staff at the Human Performance Unit at the University of Portsmouth (Danny White and Dr Jo Corbett), who offer various packages for the tests described. See port.ac.uk/about-us/our-facilities/lab-and-testing-facilities/sports-and-human-performance-testing
» This article was written and first published in AW magazine before the coronavirus pandemic