Mike007
Well-Known Member
It may feel like slow jog (and that is interesting that you found it so easy, as it suggests as I said before that you may be more endurance suited.) However from an anatomical and physiological point of view, 3k is absolutely an endurance event!
Bear in mind that, very simply put, the anaerobic energy system (which fuels fast twitch muscle fibres) runs out at around 3 minutes. The initial creatine system runs out at about 1o seconds! Fast twitch fibres fatigue quickly. So anything up to that point is classed as speed.
Beyond that time, the body switches to aerobic (oxygen and glucose) which fuels the slow twitch fibres. These fibres work at a lower intensity for longer periods but do not produce the same raw power. Hence beyond 3 mins-ish, it all becomes classed as endurance, whether it feels like it or not!
This change is fuel systems is why the human body cannot run (or cycle or swim) at sprinting speed for very long. Of course you train to improve the efficiency of the fuel systems and the removal of lactic acid, but the human body is still limited in what it can physically do.
The point that I think you have missed is that your 3 minutes of sprint ,would take you the last 3rd of the run pretty damn fast,yet over 10 k it would mean little.