coughing, shortness of breath after intense exercise

[Sleel]

They didn’t make any claims about increasing VO2-max; they were using those measurements and heart rate as diagnostics, but their focus was on actual performance (power output). As far as I can tell, what they were trying to do with that setup was simply to see which type of recovery was optimal for a common training protocol. The only conclusions you can really draw are related to work-rest intervals.

[DSeid]

Sorry that my comment was so unclear as to not be understood.

Yes, they make no comment about increasing VO2 max. The only outcome they measure is the mean peak power during the seven 5 second sprints with 20 second rests, the repeated sprint test. Which is possibly of some relevance for some athletic endevours as one small part of the fitness portfolio needed, and possibly a proxy for anaerobic capacity in very brief bursts.

It is a very narrow outcome of very little relevance to most of our fitness goals.

Here are the results from your link:

Mean peak power output in the RSS test was significantly (p ≤ 0.05) higher following PR45 than AR45 (12.0 ± 1.4 vs. 11.4 ± 1.4 W·kg−1) and following AR180 than PR180 (12.7 ± 1.2 vs. 12.0 ± 1.2 W·kg−1).

AR = active rest; PR =passive rest

The best result was AR180 by far (12.7). No 45 second rest period was superior to either 180 second rest period. PR180 and PR45 were equal (12.0)The worst for maximizing performance on the repeated sprint test was AR45(11.4).

The only conclusion that can be made is that a 180 second rest is as good or better than any 45 second rest period for improved repeated sprint test result optimization, that the best tactic between those options for that particular outcome is a 180 second rest with active recovery, and the worst is a 45 second rest with active recovery.

Any further generalization than that is speculative (such as my speculating that such might be generalizable to other repetitive short anaerobic bursts with brief recovery times as an outcome) or completely unwarranted (“better” in some broader fitness sense, for example).

Did the fitness article you read express surprise at this result? Did they try to further generalize its meaning?

[Sleel]

@DSeid

Did the fitness article you read express surprise at this result? Did they try to further generalize its meaning?

Actually, the article didn’t do much except present the findings in a more readable format, and give suggestions for designing workout templates using this information. As far as I know, there hasn’t been a whole lot of actual research on rest intervals in sprint training, so it was interesting to see some real tested information instead of guesswork and ad hoc rules of thumb.

[DSeid]

You may be interested in this summary of this article: Billat, L. V. (2001). Interval training for performance: A scientific and empirical practice. Special recommendations for middle- and long-distance running. Part II: Anaerobic interval training. Sports Medicine, 31, 75-90. I don’t have the whole article available but it seems like it would have much of the research you are interested in referenced within.

The bit that the article you cited adds is that with adequate rest interval between work sets (enough rest such that CP is reformed adequately) active rest works better. That actually has already established before too - lower level aerobic work helps clear more lactate during the rest period allowing for a better work set.

The parts that I glom onto are these:

… “It is well know that both anaerobic pathways – lactic (glycolysis) and alactic (CP degradation) – are activated instantaneously at the onset of maximal activity. However, the ability to repeat maximal sprints depends on the duration of recovery, which does not have the same effect on the two anaerobic pathways. The resynthesis of CP depends on the endurance level of the participant” (p. 78). Glycogenolysis is largely elicited in supramaximal sprints, the work intensity being well above that which allows energy to be derived from lipids.

There is a relationship between the length of the supramaximal work bout and rest. The work:rest ratios increase as the duration of work increases. For example, in the sport of swimming, 10 seconds of work can be very easily balanced by rest periods of 10-20 seconds. However, one minute of appropriate work (i.e., near race-pace for the distance covered), would require more than five minutes of rest if a reasonable approximation of the first performance is to be repeated. Not only does the rest interval change with duration of supramaximal work, but also the number of repetitions is inversely proportional to the duration of work. To derive the most appropriate training stimulation, a coach has to determine these factors along with each individual’s receptivity to this form of training. [The tendency seems to be to attempt to do too many repetitions, the latter experiences being largely detrimental to the training objectives and the individual’s welfare.] …

… There is an important relationship between type I (aerobic) and type II (anaerobic) muscle fibers. Type I fibers are more involved in the removal of accumulated lactate than are type II fibers. To increase alactic anaerobic metabolism, supramaximal sprint training acts: (a) by increasing the ability to decrease CP as rapidly as possible if rest intervals are of sufficient length to allow the restoration of the CP reserve (avoiding the involvement of anaerobic glycolysis); and (b) by increasing the ability to replenish the CP reserve as quickly as possible. To accomplish the second effect, it is necessary to have muscle fibers with a high oxidative capacity, that is a trained aerobic base. However, when rest intervals are insufficient, anaerobic lactic metabolism (glycolysis) is increasingly involved. The resulting acidosis could impair CP production (via mitochondrial creatine kinase) during recovery (p. 80).

One valuable contribution of aerobic training to sprinting is the development of the capacity to replenish, most probably in an accelerated manner, CP reserves.

The amount of supramaximal sprint training required to produce desirable physiological changes is not great [in running]. Three to four repetitions of five minutes of effective high intensity interval training per week (~20 minutes) can result in an increase in both glycolytic and oxidative muscle enzyme activity, maximum short-term power output, and VO2max. The challenge for coaches is to NOT OVERDO this form of training. It is particularly debilitating when experienced in excessive amounts. …