Comparative analysis of Hilary Stellingwerff’s physiological testing: VO2max
Test 1: Feb 2005: University of Guelph, Canada
This test was several weeks before Hilary’s participation at the World Cross-Country Champs in France. Thus, she was beginning her taper after a long-period of aerobic development. Furthermore, the period immediately prior to the test featured a fair amount of high-end sessions at or above VO2max intensity. In terms of testing for maximal aerobic capacity, since she was pretty much at peak championship form, this would have been an ideal time to attain maximal 2005 values.
Test particulars: 11 steps, over 20 total minutes: starting at 10.8 km/hr and going to 18km+4% grade (=~21km/hr on the flat).
Test 2: April 2007: LEPHE – Paris, France (V. Billat’s laboratory)
This test was conducted 5-days after her return from a 3-week altitude training stint at St. Moritz. This was probably one of the hardest 3-week training blocks of Hilary’s career, which had a focus on high quality volume, peppered with a few sessions targeted at or above VO2max intensity/speed. At this point in the season, there had not been a lot of lactate tolerance based sessions. Thus, training would suggest she was aerobically strong, but anaerobically intolerant at this point in her seasonal periodization schedule.
Test particulars: 10 steps, over 27 total minutes: starting at 11km/hr and going to 20km/hr. Also conducted a VO2max “on” test (ie. how quickly an athlete can ramp-up their VO2max), which was 110%of VO2max (=20km/hr at 5% grade for as long as the athlete can go).
Hilary’s VO2max in the 2005 test was 64.1 ml/kg/min, while in the 2007 test it was 64.5 ml/kg/min. Although these numbers are remarkably similar, there are many differences in arriving to these points. First, as mentioned above, the time of the season that the tests were taken were much different in terms of periodization towards peak championship form, suggesting that Hilary was probably in a more ideal training state to hit a relatively high VO2max in 2005, than compared to 2007. Secondly, the two tests were conducted on different metabolic collection systems (it is most ideal to use the same metabolic cart, same treadmill, same style of test). And third, the ramp test used in Paris was much longer than the University of Guelph ramp test I had implemented. The prolonged ramp test in Paris allows for a better and more accurate assessment of the training and metabolic fuel zones outlined below. However, it has been shown that prolonged tests (>20min) can cause increasing peripheral fatigue prior to reaching a ‘true’ VO2peak. In other words, currently with more VO2max training sessions, a championship peak/taper and VO2max test of less than 20min, Hilary would most likely be able to increase her current 64.5 ml/kg/min to over 70 ml/kg/min without too much difficultly.
Ventilatory & Lactate Threshold Data (or, some would argue, “onset of blood lactate accumulation-OBLA”)
Although I did not use linear regression analysis modeling to place the two intersection lines, both tests show that Hilary’s ventilatory threshold is about 51 to 52 ml/kg/min. This works on to being 78.8% of VO2max for the test in 2005 and 80.1% of VO2max in the 2007 test. Having the ability to run over a sustained period at a high-percentage of VO2max is a very important requirement for 10,000m and marathon runners; much less so for middle-distance athletes. For example, Olympic marathon runner Frank Shorter was reported to be able to run at 90% of VO2max for up to 2 hrs. Nevertheless, Hilary has improved this parameter by ~1.3% over the 2 year period. The lactate threshold data shows nearly exactly the same, with the OBLA being reached at a slightly higher 53 ml/kg/min.
Fat max is the speed or intensity when the athlete is burning the maximal absolute level (g/min) amount of fat as a fuel. This test can be highly dependant upon the recent feeding pattern of the subject, as overnight fasted athletes show a relatively much higher running speed (or % of VO2max) for fat max than compared to when recently fed. For Hilary, fax max appeared to be coming down from a maximal value at the slowest running speed of 11km/hr. For this test to be more accurate, it would have been advantageous to also collect VO2/VCO2 data at slower running speeds, as it is obvious we ‘missed’ the actual fat max. This is quite slow and at a quite lower % of VO2max compared to some of the scientific literature. However, the scientific literature uses subjects that are overnight fasted, while Hilary did this test in the fed condition. Fat max is very important for longer duration races (ie. marathon runners) and less so for middle-distance athletes. Nevertheless, Hilary’s ability to utilize a high proportion of fat at lower to moderate running speeds appears to be underdeveloped. Therefore, making sure that all easy/long running is done well below threshold, to fully utilize and maximize fat/aerobic enzyme capacities, will slowly develop this ability.
VO2 “ON” Kinetics: only assess in 2007 in Paris
The nature of modern elite middle-distance racing is that it is nearly a sprint for the entire race of ~2 to 4 min. Thus, one of the most important physiological criteria for a middle-distance athlete is the ability to “turn-on” on the aerobic system to maximal values in as short as time as possible. Therefore, assessing VO2 “on” kinetics is a vital test for middle-distance athletes. This was done by having the athlete run at ~110% of VO2max for as long as possible (in this case at 20km/hr up a 5% treadmill grade). Hilary was indeed able to reach VO2max again, and in only about 2min and 30 seconds. My limited understanding of this test (but in communication with Paris Professor V. Billat) was that this was very well developed in Hilary and of a very elite level.
Calculated training targets from the physiological thresholds
Taking the ‘projected’ fat max, lactate/ventilatory thresholds and plotting them against running speed and HR allows one to figure out individualized training target zones.
Hilary’s targeted running speeds to both recovery, but also to develop fat/aerobic enzymes and pathways is ~10 to 12 km/hr (or about 8min/mile, and building from there).
Tempo/threshold runs should be at a HR of ~180 to 185 beats per minute and is about 16km/hr (or 6min/mile). This has been improved, as 2 years ago, threshold pace was ~15.5 km/hr.
Running Economy Comparison