Significance of the Velocity at &OV0312;O2max and Time to Exhaustion at this Velocity

Abstract

In 1923, Hill and Lupton pointed out that for Hill himself, 'the rate of oxygen intake due to exercise increases as speed increases, reaching a maximum for the speeds beyond about 256 m/min. At this particular speed, for which no further increases in O2 intake can occur, the heart, lungs, circulation, and the diffusion of oxygen to the active muscle-fibres have attained their maximum activity. At higher speeds the requirement of the body for oxygen is far higher but cannot be satisfied, and the oxygen debt continuously increases'. In 1975, this minimal velocity which elicits maximal oxygen uptake (VO2max) was called 'critical speed' and was used to measure the maximal aerobic capacity (max Eox), i.e. the total oxygen consumed at VO2max. This should not be confused with the term 'critical power' which is closes to the power output at the 'lactate threshold'. In 1984, the term 'velocity at VO2max' and the abbreviation 'vVO2max' was introduced. It was reported that vVO2max is a useful variable that combines VO2max and economy into a single factor which can identify aerobic differences between various runners or categories of runners. vVO2max explained individual differences in performance that VO2max or running economy alone did not. Following that, the concept of a maximal aerobic running velocity (Vamax in m/sec) was formulated. This was a running velocity at which VO2max occurred and was calculated as the ratio between VO2max (ml/kg/min) minus oxygen consumption at rest, and the energy cost of running (ml/kg/sec). There are many ways to determine the velocity associated with VO2max making it difficult to compare maintenance times. In fact, the time to exhaustion (tlim) at vVO2max is reproducible in an individual, however, there is a great variability among individuals with a low coefficient of variation for vVO2max. For an average value of about 6 minutes, the coefficient of variation is about 25%. It seems that the lactate threshold which is correlated with the tlim at vVO2max can explain this difference among individuals, the role of the anaerobic contribution being significant. An inverse relationship has been found between tlim at vVO2max and VO2max, and a positive one between vVO2max and the velocity at the lactate threshold expressed as a fraction of vVO2max. These results are similar for different sports (e.g. running, cycling, kayaking, swimming). It seems that the real time spent at VO2max is significantly different from an exhaustive run at a velocity close to vVO2max (105% vVO2max). However, the minimal velocity which elicits VO2max, and the tlim at this velocity appear to convey valuable information when analysing a runner's performance over 1500m to a marathon.

Effects of Resistance Training on Running Economy and Cross-country Performance

“…Peak running speed has been shown to be a good indicator of endurance performance in middle-and longdistance running events (4,34,35,41,47) and Noakes (34,35) has suggested that peak running speed could be used as a measure of the 'muscle power' factor in endurance runners. Muscle power is defined as an ability of the neuromuscular system to produce power during maximal exercise when glycolytic and/or oxidative energy production are high and muscle contractility may be limited (34).…”

Performance Training Guidelines for the 1.5 and 2-Mile Runs

“…The authors later demonstrated the test's reliability with various populations. 53 Because Billat et al 19,49 found that the Tlim usually ranges from 3-12 minutes, we propose that it may be appropriate to initially implement run programming with healthy military populations based on Berthon's 5-minute estimate of vVO2max. 52 Daniels' 10-12 minute method may be more appropriate for testing in well trained runners.…”

“…8 Brandon & Boileau 18 indicated that anaerobic factors appear to have a direct influence on performance at 1,500 m and 3,000 m, so including a moderate training emphasis on anaerobic factors may yield performance benefits, particularly because the training intensity is higher than typical long, slow distance (LSD) running. Billat 19 noted that [sustained] running speed is influenced by a relationship between running economy-steady state VO2 at a given submaximal speed 20 -and LT, which determine the percentage of VO2max used in runs beyond 10 minutes in duration. LT may be altered considerably with appropriate training.…”

“…The training state of runners has been observed to play a role in how long they can sustain vVO2max. Billat et al 19,49 studied maximal time (Tlim) at vVO2max during incremental tests and found that Tlim ranged from 3-12 minutes. Hill & Rowell 50 found that in a group of highly trained middle-distance runners 60% of the Tlim is sufficient to reach VO2max.…”

Time to exhaustion during severe intensity running: response following a single bout of interval training

“…A velocity of 1 km.h -1 below v- VO2 max rather than v- VO2 max, which has been widely used to determine t lim previously (Billat and Koralsztein, 1996), was chosen in light of the expected t lim . To determine a difference in  VO2 between 2 min 30 s and the end of exercise, t lim had to be long enough to make at least two reliable samples of expired gas (i.e., > 210 s) in all three severe intensity tests.…”