Running - Limiting Factors
You want to run faster? Of course you do! So you have to produce more power, which means you have to work harder. In fact you have to be strong enough to produce the pain, and tough enough to withstand it. Basically, you won't go faster without trying harder.

But this line of reasoning very quickly leads people to be concerned with effort, almost to the exclusion of everything else. The danger is that they become slaves to their effort meters (ie their heart rate monitors), and they lose sight of all the other factors that are important components of fitness. The HRM tells them to slow down if they are working too hard; or to increase their effort if their heart rate is below their threshold level. Very quickly the HRM starts to govern their training - and even their racing.

Sure the HRM is an extremely useful tool which can give you invaluable feedback information, and which can help you achieve exactly the level of intensity that you plan for each session. But it is only a tool. And it can become a misleading tool if it leads you to the conclusion that more effort will automatically produce more speed.

Ask the swimmers and the cyclists - they are forever stressing technique and form as the key to speed. What is required is not more effort, but better balance, timing, co-ordination and relaxation. Triathletes often realise that these are the vital 'missing ingredients' in their swimming and cycling, but then completely disregard them when it comes to running. And yet the evidence is always staring us in the face when we see the experts perform - they simply ooze skill, and make everything look so easy.

Again, as with swimming and cycling, running skill is not just about moving well at slow speeds or short distances. The real skill is to be able to maintain good form at speed, and under severe stress. Lack of strength, stamina or speed will quickly start to limit your ability to maintain both form and pace. Your response, almost always, will be to increase your effort, but the result will usually be the opposite of what you intended - ie you will slow down even more.

Hopefully we can now see that running ability is governed by a number of factors, each one of which can prove to be the limiting factor in different circumstances. It is not always the same factor which cuts in and proves to be 'limiting'. You may be strong enough to run a good half marathon, but strength may prove to be a limiting factor in a shorter race eg 5k. Your stamina may be fine for distances up to 10k, but may well let you down in a marathon. You may well be able to run at a fast pace for up to 1 minute, but if you quickly get into oxygen debt (ie have a low anaerobic threshold level), or are unused to operating at fairly high levels of lactic acid (ie anaerobically), your speed will rapidly tail off.

It helps to be even more specific about the factors which come into play to limit our performance. If you suddenly get badly out of breath following a slight increase in pace, or running up a slight incline, this indicates a low anaerobic threshold level. This could be due to a number of reasons - perhaps a small, or even a large but weak, heart; a small lung capacity, or a poor rate of oxygen absorption from lungs to bloodstream and/or from blood to muscles. This symptom of breathlessness might also indicate a poor ability to disperse and/or tolerate lactic acid in the muscles.

With a little imagination you can devise specific training sessions to target each of these 'limiting factors'. By doing so you will extend your ability to cope with a broad range of potential 'limiting factors', instead of training in such a way as to constantly come up against the same limiting factor. There are additional benefits too - your training programme will become much more varied; you will use different energy pathways for different sessions, thereby avoiding deep and damaging muscle fatigue; and you will recruit different muscle fibres over different ranges of movement, thereby improving strength and suppleness, and helping to avoid over-use injuries.

When planning your training programme, you should clearly understand exactly why you are doing each session, and what training effect you are looking to achieve. If you are looking for speed and power, make sure that you give yourself sufficient rest between efforts. If you are looking to improve your speed-endurance and your recovery rate, make sure you run fast efforts, but over manageable distances, and that you keep recovery periods as short as you planned. If you are looking for recovery runs, or long steady runs to improve muscle capillarisation, or even longer runs to develop fat-burning efficiency, choose suitable speeds and distances, and don't let the runs develop into races just because you feel easy. (A HRM is ideal on these runs, to act as a 'governor'.) If you are looking to develop lung capacity, and heart power (ie not just size), make sure you raise your heart rate well above ATL. Even if you use a HRM for these sessions, let it be your breathing rate, rather than your heart rate, that is the limiting factor.

The following is a summary of potential limiting factors, and some suggestions of specific sessions to target specific weaknesses.