28. Nov, 2020
VO2MAX – SIT vs HIIT
There is a lot of discussion in endurance circles around the benefits of SIT vs HIIT training for increasing VO2MAX and thus improving your POWER DURATION CURVE. Increasing VO2MAX increases your oxygen uptake capability and utilisation by the muscles which basically means that you can go harder for longer.
VO2MAX
The maximum amount of oxygen a person can utilise during (intense) exercise.
POWER DURATION CURVE
Maximum power that can be held for given periods of time. For short periods of time individuals can hold high intensity, but that intensity will drop as exercise time increases. The aim of the game is to both lift the maximum intensity level and prolong the time spent at that intensity (flatten the curve drop-off). With an increase in VO2MAX comes an increase in the sustainable intensity for both longer and shorter periods-you can go harder for longer.
TIME@VO2MAX (T@VO2MAX)
Measure of the accrued time @VO2MAX during a workout usually expressed as a percentage of the entire workout or in minutes.
VELOCITY@VO2MAX (v@VO2MAX)
The pace individual can sustain at VO2MAX (average km pace or km/hr). A good way to estimate your v@VO2MAX for running is to complete a 5min distance trial (after a warm-up) on a flat course-your average speed is your v@VO2MAX. A good field test for estimating riding v@VO2MAX is a 20min distance trial (flat course and after warm-up).
The question then becomes which form of exercise will best increase the VO2MAX for an individual which in turn will allow them to go harder for longer.
VO2MAX has been shown to improve by training at or around (75%-100% (90% seen as ‘optimal’)) your VO2MAX for 10-20min, 2-3 times a week. It is here that the distinction between T@VO2MAX and v@VO2MAX comes in to play.
It is important to note that it usually takes 3min in the first interval and 1-2min in subsequent intervals to reach optimal training % of VO2MAX. As a result of this T@(or around)VO2MAX is less than the time spent at v@(or around)VO2MAX.
SIT-Sprint Interval Training
Performed at maximum power an individual can hold for 30sec-1min 30sec
E.g. All out 200m sprints with 200m walk recovery
HIIT-High Intensity Interval Training
Performed at or around VO2MAX for 1:30-4min
E.g. 4 x 4min at 90% of VO2MAX velocity pace with 4min recovery between each effort.
It takes many more SIT intervals to accrue T@(or around)VO2MAX than with HIIT sessions as distinct from reaching v@(or around)VO2MAX. As a result of this it would appear that HIIT sessions are better suited at increasing individual’s VO2MAX and thus being able to go harder for longer.
Happy training,
Peter