Antonio,
Sorry I am replying to your post so late. I have been very busy.
As for Question 1.
Aerobic power workouts are very stressful workouts, and it can take a long period of time to recover from these workouts. I believe they can increase aerobic capacity by themselves but I do not believe that this is the best way. It can take a very long time to recover from these workouts, and because of this volume of training performed may have to decrease. Intensity has been shown to be a better stimulus than volume in the short run, but you can only do some much intensity before you begin to break down. It can take many easy regeneration days of long slow running to recover enough to be able to do another hard workout. Athletes definitely need to switch to a more intense and less volumous type of program before a peak race. This is very specific training, and is focused on performance more than the overall fitness of any energy system. Less intense and more volumous training, done around or below the AT allows athletes to perform more work over time. This may allow an athlete to maximize the development of their aerobic capacity more effectively than by incorporating much more race specific aerobic power workouts. Hence the need for a base phase. Of course I am guessing that the athlete has time for a base phase, since more time is required to train this way. A periodized program requires patience. We can definitely mix the two a little bit though and achieve good results. Recovery and regeneration are key here though. Athletes require a lot of easy regeneration running in between each hard workout. As long as the athlete is absorbing the workouts and improving, I see no reason not to train along this path. The important thing is to make sure that the athlete is not overdoing the aerobic power running. If they overdo it they may lower their anaerobic capacity to very low levels, and will then be in danger of over training, because more and more of their running will be training their aerobic power than is desired.
As for question 2.
I am not sure what you mean by anaerobic training. I use Olbrecht’s term of anaerobic capacity training only because that is how he describes it. Although it is anaerobic in nature, I do not believe creating oxygen debts is the focus of the training. Anaerobic capacity training is mainly designed to increase the athlete’s ability to utilize sugar as fuel (glycolysis). This provides the athlete with another fuel source other than fat, and provides energy very quickly when needed.
Anaerobic power training on the other hand is designed to purposefully put an athlete in oxygen debt. This training is therefor very anaerobic.
If your test runs are at speeds and distances that test an athletes aerobic capacity to its limits and beyond, then yes I believe it is anaerobic training. I believe the type of workout you describe is what some call speed endurance. I have seen two ways of doing this type of workout. In the first the athlete runs a very fast pace over a relatively short distance (about 200-400m) but utilizes very short recovery periods of about 30-60 seconds. Lactic acid never gets cleared very much because of the short recoveries and the athlete gets more and more into oxygen debt as the workout progresses.
The other way to do this type of workout, and I believe this may be what you are referring to (correct me if I am wrong), is to do much longer repeats with a necessarily much longer recovery period. Athletes find these much harder to do and I don't see many even try them because they require great concentration and they can hurt a lot, especially at 800m race pace. Because of the distance of the repeats the athlete can get deep into oxygen dept, and the recovery period is not very important since the training adaptation is achieved by utilizing longer repeats. The goal is to try and run longer and longer at the desired pace. I believe Seb Coe used to work up to doing repeat 1200m at 1500m race pace with long full recoveries in between. This is one tough workout, and I doubt there are many in the world who can or would want to do this.
Hope this helps clarify my take on these things.
On a side note, the longer the recovery periods are between aerobic power workouts the more anaerobic the workout will be. The aerobic capacity does not initially start to work to its capacity as the athlete starts to increase pace. Oxygen debts can be created early on in a repetition, but can be reduced as the aerobic capacity catches up the energy demands of the chosen activity. So if the athlete is training at a speed within the athletes aerobic capacity but wants to make the workout more anaerobic they could increase the recovery period to allow the aerobic capacity to shut down a bit, before starting the next fast run. Standing still before the next run would aid in this. Short recoveries on the other hand will ensure that the athlete’s aerobic capacity is still being utilized and ready for the activity. This will reduce the likelihood that any oxygen debts are being produced at the beginning of the next fast repetition. Active recovery is recommended for this method of course.