A Basic Scientific Look at 100m Running

| |

After my basic scientific look at 400m running, I wanted to create a similar piece to look at another event, this time the 100m.  Whilst there is a lot more research surrounding 100m sprinting in relation to things such as specific genetic factors that may play a big role in determining an athlete’s potential capabilities, I am going to take a similar approach to this article as I did for the 400m piece and look at the basic fundamentals of running the 100m.  

The 100m sprint is often thought of as the showpiece, blue riband event within the world of track and field, drawing the biggest audiences and providing us with some of the world’s biggest sporting celebrities. Whilst some might view the event as nothing more than a simple all out sprint from point a to point b, the physiological, biomechanical, biochemical and psychological components that make up an elite level 100m performance are in fact incredibly complex and need to work in perfect synchronicity at their highest capacity to produce the perfect 100m sprint.

Tactics

Whilst some could potentially take the view that tactics don’t play a role in 100m sprinting, per se, there is definitely a large body of evidence that suggests the need for a well executed race strategy in order to produce optimal performance in the event. Similar to point that I made in my previous article, athletes nowadays are (usually) made aware from a young age that you cannot simply stand up and try to run as fast as possible if you’re looking to run quick times in the 100m.

There are a series of sections to the race that need to be pieced together effectively in order to produce the optimal 100m sprint. A theory of having multiple phases to a race was introduced, implemented and  popularised by John Smith in the late 90’s which was designed to delay athletes acceleration phases until further on in the race in comparison to what people had done previously. Smith’s proposed there should be 7 phases to a 100m race, which are: reaction time, block clearance, drive, transition, acceleration, maintenance and deceleration. Whilst often now condensed down by coaches in to 3 or 4 phases (e.g. drive, pick up and flight phases), this approach still provides the template around which sprinters are taught to execute the best possible race.

Comparing data from the 1992 Olympic men’s final, in the ‘pre-drive phase’ era, against more modern data from the 2009 World Championship final it can been seen that this approach does seem to be more favourable. Athletes today do indeed they do reach their highest velocities later on in the race compared to their counterparts from 20years ago, however they are able to maintain a higher percentage of this top speed for longer which allows for a faster time overall. Typically athletes have their fastest 20m section between 60-80m now, during which time their average stride frequency is at its peak and average stride length is nearing its peak (typically athletes show a slightly longer stride length in the final 20m).

Biochemistry

Because sprinters need to achieve and maintain very high power outputs during 100m sprinting, the body’s energy systems have to work extremely hard to try to provide enough energy, in the form of ATP, to cope with the highly taxing requirements of the event.

Whilst typically thought of as purely an anaerobic event, it has been shown that around 10% of the energy contribution for 100m sprinting does actually come from aerobic metabolism, with the remainder being supplied by anaerobic glycolysis and phosphocreatine (Pcr) breakdown.

Whilst Pcr is probably the most important means of ATP resynthesis during sprinting, as it has the highest potential power output of all three energy systems, it also has the lowest capacity and therefore will not last for very long.

A practical example which highlights the invaluable contribution of this energy system and where it breaks down is to look at 60m running. Up until this distance, elite sprinters will typically show no form of deceleration or signs of fatiguing, however, beyond this distance if they were to run a full 100m, noticeable signs of fatigue and deceleration will begin appear towards the end of the race. Data shows that whilst the 60-80m section of an athlete’s race is typically the fastest, the speed over the next 20m will be similar to that of the 40-60m section if not slightly slower. This can potentially be attributed to the bodies Pcr stores beginning to deplete rapidly as the sprint progresses and thus ATP resynthesis requiring a greater contribution from anaerobic glycolysis (and a small amount from aerobic metabolism) to maintain performance as best as possible.  

Physiology

Generally, in elite sprinters you will find a very high proportion of type II muscle fibres, these fibres possess the potential to produce the high forces and speeds of contraction needed for sprinting. It has been shown the ATP concentrations in type IIx fibres (the fastest contractile fibres that human skeletal muscles possess) decrease rapidly at the onset of maximal sprinting, much more so than type IIa and type I fibres, which highlights the intense activity that it going on within these fibres during sprinting. The greater the content of type IIx fibres one possesses would, therefore, appear to be a key predictor of potential sprint performance. Whilst some evidence exists suggesting that some people are born with genetic predispositions for expressing a very high proportion of fast twitch fibres, particularly type IIx fibres, which account for their natural raw speed, many believe that (and have shown evidence for) the possibility of one dramatically changing the fibre type composition of their muscles through training.

 

References:

The Biochemical Basis of Sports Performance – Maughan and Gleeson (2004)

IAAF New Studies in Athletics: Sprints. – NSA (2011)

https://brianmac.co.uk/sprints/index.htm

https://www.adriansprints.com/2010/10/maurice-greene-100m-race-strategy-john.html