How does one train for sports when the three metabolic pathways interact?

Question

As I understand it, there are three mechanisms by which ATP is replenished:

1. For intense 10-12 second efforts, ADP is directly converted back to ATP using creatine phosphate

2. For efforts up to a couple minutes, ATP is produced by glycolytic metabolism

3. For longer efforts (several minutes or many hours), ATP is produced by oxidation of fatty acids and glycolytic products

(Source is nearly verbatim from Mark Rippetoe and Lon Kilgore's Practical Programming for Strength Training, 2nd edition, page 57)

If a particular sport engages two different metabolic methods, A) how does that interaction work, and B) how does one condition for it?

For example, many running-centric team sports like soccer are clearly in the third category (running for twenty minutes to maintain positional control of the field). Those same sports occasionally require intense spurts that would clearly fall in the first category (sprinting on a breakaway).

Is sport-specific training (e.g. scrimmaging) best for training this interaction between the two pathways? Is training each pathway individually (e.g. sled drags in one workout, distance running in another) sufficient? Does conditioning have to be combined in the same specific manner that mimics lower-intensity work interspersed with bursts of hard effort (e.g. Indian runs)?

Update: to be clear, I am looking for an explanation of the physical or physiological phenomena going on here. I am not looking for advice on a training regimen, unless it specifically explains why and how it is most effective, using either science or competition.

Answer 1

There are a large number of different catabolic pathways that the body uses, of which the the aerobic/anaerobic dichotomy you present is a useful characterisation.

These processes are not mutually exclusive of each other, but instead occur continuously regulated by enzymes in the various tissues which themselves respond to the concentration of chemicals in the body as indicators of the type of load the body is under. See: http://www2.ufp.pt/~pedros/bq/integration.htm:

Muscles use glucose, fatty acids, ketone bodies and aminoacids as energy source. It also contains a reserve of creatine-phosphate, a compound with a high phosphate-transfer potential that is able to phosphorilate ADP to ATP, thereby producing energy without using glucose. The amount of creatine in the muscle is enough to sustain about 3-4 s of exertion. After this period, the muscle uses glycolysis, first anaerobically (since it is much faster than the citric acid cycle), and later (when the increased acidity slows phosphofrutokinase enough for the citric acid cycle to become non-rate-limiting) in aerobic conditions.

The oxidative pathways run fairly continuously to maintain life and replenish tissues that have made use of anaerobic energy conversion. Some of the intermediate products of cycles will up-regulate other cycles.

On a practical level, there seems to be good evidence that high intensity interval training has strong effect on medium term endurance at the same time as improving short term sprinting abilities and strength, unlike lower intensity 'steady state' activity that relies mostly on oxidative pathways which only really develops the former. See for example Tabata et al: http://www.ncbi.nlm.nih.gov/pubmed/8897392 (often trotted out), and more recent publications that cite it: http://www.ncbi.nlm.nih.gov/pubmed?db=pubmed&cmd=link&linkname=pubmed_pubmed_citedin&uid=8897392.

For hardcore endurance like marathon running and long distance cycling and swimming, my understanding is that you would need to train differently to get the training adaptations that might want to help with fuelling and so on.

Answer 2

JudoFitness asserts that the three pathways smoothly shift gears when training hard for extended periods of time:

Note the significant overlap as one pathway depletes itself and the next takes its place.

The author uses the example of a long stair climb, performed explosively for as long as the phosphagenic pathway can sustain, then less explosively but still hard for as long as the glycolytic pathway can sustain, then relying on the oxidative pathway for the remainder.

Regardless, the author suggests doing pathway-specific training in addition to sport-specific sessions. I suspect that this is because a multi-pathway training session would lend itself heavily towards the glycolytic or oxidative, leaving the phosphogenic pathway undertrained.

Answer 3

I would say do all of what you mentioned!

If your sport is soccer, do sprints AND endurance training. Not on the same day, though.

A sprint workout will tax your muscles' explosive capabilities and especially your nervous system. You want to stay away from fatigue, as the goal is to teach your body and brain how to move at the highest speed possible. Sprint practice on sluggish legs doesn't do this. You want full recovery in between sprints.

On the other hand, a long running workout should be focused on building your endurance at a pace that is sustainable for long enough that you actually do reach your endurance limits. If you're running too fast, you won't reach that limit. I like to think about endurance as running at a pace where you can get "in the zone," where you can go for a loooong time (think a 90 minute soccer match).

Sport specific training, then, would be where it all comes together. Doing all the springs and 5-mile runs in the world won't help if you can't dribble or pass the ball! But, they will help you elevate your game to a new level as your sport-specific skills progress.

Basically, there's no reason you shouldn't be able to do all of the things you talked about. But, make sure that each training session has a goal in mind - if you're doing a sprint workout, the goal is speed! So don't tire out your legs. And if you're going for distance, the goal is endurance - so run at a pace that you can sustain to reach true endurance limits.

Answer 4

Great question. Progressive loading is the best strategy. In other words, start easy and increase load (difficulty, stress) as you gain strength.

In my experience, it is best to train each pathway independently when possible, at least at first. Part of this reason is that lactate (anaerobic conditioning) interferes with the production of the aerobic enzyme. Would recommend aerobic to be the base of everything you do with anaerobic load to gradually increase.

For example, in week 1 of training, perhaps only do 10-15% anaerobic work such as hill sprints or suicides. As you get closer to key competitions, gradually build the anaerobic portion up to maybe 50% of total work. The aerobic conditioning will always be the key though. As the season progresses, mixing the two and game scrimmages will allow for better development. It is crucial that hard days are followed by easy days as well.

The Creatine Phosphate system can be developed at all times of the season. The key to ATP-CP development is the work (7-10 seconds max) and rest periods (3-5 minutes).

3 great ways to develop ATP-CP?
1) 60m accelerations to top speed. Turn around, walk back, wait 3 minutes before doing another.
2) Short hill sprints up a steep incline lasting no more than 7-10 seconds. Jog back, rest 3 minutes.
3) Deadlifts at 85% max with 2-3 reps. KEY TO NOT GAINING MASS is to rest 5 minutes between sets and no more than 2 or 3 sets. This exercise does wonders to also gain speed endurance. EVERY athlete can benefit from this regardless of sport and it can be performed 3 times a week.