running economy is a complicated topic and hard to measure, but a common measure of economy is done through vo2 (volume of oxygen) measures as a proxy. according to wikipedia, “Those who are able to consume less oxygen while running at a given velocity are said to have a better running economy”.
i put together a few visuals to illustrate this concept better.
here’s a graph showing
- oxygen consumption or vo2 on the y axis
- velocity in meters per second on the x axis
- as velocity increases, so does oxygen consumption. they increase together up to a point (vo2 max)
- oxygen consumption plateaus / steady states at the vo2max at and beyond a specific velocity
now, if the athletes is able to train their aerobic system to run at the same velocity with lower oxygen consumption, you get this graph
- the dotted black vo2 consumption at given pace is the original line. the new solid line is as a result of training
- same pace, but lower o2 consumption. this athlete has improved their running economy!
- similarly, if you graph the relationship between vo2 and velocity for different athletes, the one with the lower vo2 consumption at any given pace is more economical
i also find this relationship interesting because it also tells you why increasing vo2 max is valuable. vo2 max sort of represents near maximum / max effort and running at vo2 max typically can’t really be sustained for longer than 11 minutes. right now, the athlete can only run at their max for 11 minutes. if you shift the max up, here’s what happens
- the previous velocity is now a fraction of max, so less effort is required to sustain the same pace. they can now race at that same pace for longer! better endurance
- the new max is associated with higher velocity. their previous 11 minute high effort pace is even faster
precise vo2 max testing is typically done in a lab hooked up to an mask that measures oxygen consumption while running on treadmill at increasing intensity. one of my favorite running youtubers / olympic athlete is luis orta (venezuelan runner). he does a vo2 max test here and gets an 80 mL/kg/min.
that is a ridiculous number because the average vo2 max for untrained individuals are around 30 – 40!
vo2 max at the end of the day is just a metric / one indicator. i used to see vo2 max videos everywhere on youtube when i first started running and it made me feel like i somehow needed to track it as part of my training. completely untrue.