Your body produces energy. Running uses this energy. Running faster uses energy faster, and consequently your body has to make it faster.
This should be agonizingly clear so far.
Because there is a maximal pace at which your body can produce energy, the key to making successful improvements in endurance running is maximizing total energy production while using that energy as efficiently as possible. Whether it's 2 miles or 20, all you have to do is produce the highest possible amount of energy over the course of the distance- and not waste it with inefficient running form.
What makes this challenging is that faster ATP production (anaerobic) is the main cause of fatigue, while slower energy production (aerobic) comes to you virtually fatigue-free.
So naturally you could run a pretty long distance really slow, but that's not very impressive. And you can probably run a really short distance super fast, but if you stop running 15 seconds into a 10k, you're going to be ridiculed by everyone in the world. Rather, what you want to do is find a balance between your aerobic and anaerobic energy production. A balance that will allow you to endure the distance while producing energy faster than what your aerobic capability by itself allows.
Knowing that the human body is constantly using both energy cycles, and the amount of anaerobic energy produced is dependent on controllable factors, this is completely feasible.
We'll talk about the training techniques to make improvements now, but in order to do that, we're going to split it up into three components: Aerobic energy production, anaerobic energy production, and running technique.
The only reason we're starting with this one is because there's not much to it. All you have to do is run fast for a while and pay attention. When you start to get tired but you keep on running as fast as you can anyway, you should notice your stride begin to lengthen and you start relaxing all the muscles that aren't involved specifically in your running. The only reason you're doing these things at the time is because it feels better without really slowing you down. The reason it feels better is because you're being more efficient with the energy you're producing, and therefore the painful parts of fatigue are impacting you less. This is your new permanent running form. It should be your exact form from the beginning to the end- right on pace. I feel this sums up everything you need to know about form. If you disagree, ask somebody else for further advice.
This is produced through oxidative phosphorylation. If you run at a steady pace, and breathe while you run, you're using this energy cycle a lot. It relies solely on oxygen consumption and transport. If that steady pace is fast enough to challenge your breathing, you're using oxidative phosphorylation at or near its max rate. This is good. A) This max rate doesn't cause you to fatigue at all, and B) your max rate will improve with training. It's definitely in your best interest to take full advantage of this energy production.
As I mentioned earlier, running at a steady pace is the way to challenge this system of energy production. If you're at a steady pace, your oxygen intake and transport can remain constant with the use of it in your legs. Realize that it takes a period of time for your blood to pick the oxygen up from your lungs and transport it through the blood to the working muscle. If you're constantly increasing and decreasing the amount of oxygen you're using (by changing your pace), it's difficult for your body to perfectly match up oxygen you take in through your lungs with the muscle's use. Every time you increase your pace, the muscle's demand for oxygen goes up beyond what is available, and then your breathing has to increase, and then your blood has to pick it up and transport it, then offload it into the muscle. Even if it only takes 30 or 40 seconds, that's a good chunk of time where your aerobic, fatigue-free energy production isn't working maximally, and your anaerobic energy is picking up the tab, causing fatigue much faster than you want. You shouldn't let this happen. You want the most out of your aerobic energy system as possible. So pace yourself steadily through the whole race.
Energy demands beyond what oxidative phosphorylation can provide are forwarded to glycolysis, your anaerobic energy cycle. And as we just mentioned, glycolysis is also the primary contributor for energy demands resulting from incremental increases in the intensity of your pace. Glycolysis is what produces lactic acid, and lactic acid is a huge cause of fatigue in distance running. It's also a tricky little bastard, and the controllable factor I referred to at the very beginning of this article.
Lactic acid buffering, threshold, and tolerance are the three components of fatigue we need to know about here. Glycolysis yields lactic acid as a byproduct of its ATP production- and places it right into the cytosol of the muscle (the only area directly affected by it). This lowers the muscle's pH. The lower the pH falls, the more that muscle's contractility is hindered. The more the contractility is hindered, the more you fatigue. The more you fatigue, the more your performance is compromised. Yay!
Luckily we have a buffering system, where your body is constantly removing and metabolizing the lactate so that you can continue to perform. But when the lactic acid production exceeds the buffering, you reach your "lactic acid threshold" and the amount in the cytosol begins to rise quasi-exponentially. Let's just say it rises fast. And this fast rise causes the pH to drop further and further, eventually compromising your muscle's ability to contract entirely. But the amount of time one can go in an acidic environment is adaptable, giving rise to lactic acid tolerance.
Lactic acid buffering, threshold, and tolerance are three of the most importance attributes of your fatigue and all of them are adaptable- and knowing this, the pace you will perform best at, is that which fully utilizes maximal aerobic capacity (fatigue free energy) on top of glycolysis yielding the exact amount of ATP by which the affiliated lactate production can just barely be buffered and metabolized and/or endured while performing. Depending on your total distance, it may just be a tiny bit of added glycolysis (huge distance), or tons if it's not too far.
If this makes sense, we can finally get to the training methodology to improve your performance by these measures.
How to train accordingly:
Early in the training season, everyone is out of shape. The whole metabolic apparatus by which you perform won't be able to efficiently meet demands regardless of what they are. And beyond that, the muscles themselves aren't ready to perform. Plus, all the benefits you could achieve from legitimate training at this point, you can achieve just as well by taking it easy. So at the onset of training, pushing yourself accomplishes very little.
Do your first 6 workouts at a fairly easy intensity. Just a nice slow pace over a progressively increasing distance. In doing so, you're preparing the soft tissues for future training as well as increasing mitochondrial mass in your muscle so that more oxygen can actually be used. This will improve your lactic acid metabolism with minimal energy.
The next session do a warm up followed by a timed trial at full effort. Write this time down. You'll need it to create your training pace.
For training day 8, you need a stopwatch that you can carry with you while you run. You are to begin interval training (walk, run, walk, run, walk, run, etc.) for a set time period, covering as much distance as you can given the constraints of the program. Whatever time you got on your time trial, that will be your total running time and it must be completed in 10 segments with diminishing walking time.
Example: If your time trial took you 20 minutes, you are to spend 20 total minutes running, but it must be done in 2 minute intervals. 2 minutes of walking, 2 minutes of running, 2 minutes of walking, 2 running, 2 walking, and so on until 20 total minutes of running is completed (in addition to the walking). If it took you 40 minutes, you are to run for 40 minutes in 4 minute intervals. 4 walk, 4 run, 4 walk, etc until 40 minutes of running is completed. Make sure you always start with a walking interval.
The reason you need to start with walking is because going from nothing to high level activity encourages more use in glycolysis where as spending several minutes at lower level activity before going into higher levels enables the body to use oxidative phosphorylation to a greater degree at that higher intensity. The simple fact that you're doing interval training and experiencing incremental increases in intensity means that you're going to have tons and tons of anaerobic energy being produced. And the lactate byproduct of this is accumulative, so your anaerobic fatigue resistance is being challenged like crazy already. You walking for your first interval helps you involve your aerobic energy system a little more as well.
Every consecutive workout, take 10 seconds off the walking time intervals. So the first workout would be 2 walk, 2 run, 2 walk, etc. The second workout: 1:50 walk, 2 run, 1:50 walk, etc. The third workout: 1:40 walk, 2 run, etc. The fourth: 1:30 walk, 2 run, etc. All the while, do everything in your power to cover the same total distance every practice despite losing walking time. The walking portions challenge your aerobic metabolism to resynthesize your anaerobic energy substrates (produce free ATP, replenish creatine phosphate stores, and convert lactate back into useable carbohydrates). Challenging the time allotted to your aerobic metabolism through progressive segmental decreases in the walking phase slowly shifts your metabolic apparatus to operate according to the specific stresses of your exact event. It basically improves your aerobic capacity to exactly what you need.
When your walking time finally becomes 0 seconds, it's your second time trial. Run it as fast as you can because this time determines your next pacing strategy. After finishing the run and writing down your time, take a few days off. This is mandatory.
After your few days of rest, you start up your new program. Let's say that you got 20 minutes on your first time trial and 18:30 on your second. Because this was a minute and a half faster, you are to take another minute and a half off, making it 17 minutes. Whatever the improvement was, calculate that exact same improvement into your second time trial as a goal pace, using that as your new total practice time.
Ngt a=. Whoops. For as many practices as it takes, your new practice regimen looks like this: Warm up. Run at a very steady pace for that exact amount of time. Stretch. Go home.
While running for that exact amount of time, if you're not completely exhausted the second the time is up, you're not training hard enough. The idea is that you'll be running at a faster pace than you would if you were covering the full distance, and this improves everything that extra long distance training cannot.
However, once every 10 practices, do train at an extra long distance, as it builds respiratory capacity. But don't do it any more frequently than this as that's all it builds. It does very little to increase your lactate metabolism and tolerance, increase your VO2
Max, or improve the skill and form of running at a competitive pace. And your shorter practices are doing exactly those things.
During these short practices, keep tabs on the distances you attain. The idea is that you cover more and more ground every practice until your race distance has finally been covered completely. When this happens, your time trial goal has been achieved and you have my permission to do whatever you want for training, but I say you're competition ready.
If you'd like to go back to the interval training protocol again and go for a new personal record, that's fine. Just do whatever.
And as a general guideline regarding the frequency of your training, 5 days per week max and 3 days minimum. That's all. The end.