RESULTS: After training, the experimental group increased their respiratory muscle endurance capacity by 12%. Performance on a bicycle time trial test designed to last about 40 min improved by 4.7% (9 of 10 subjects showed improvement). There were no test-re-test improvements in either respiratory muscle or bicycle exercise endurance performance in the placebo group, nor in the control group. After training, the experimental group had significantly higher ventilatory output and VO2, and lower PCO2, during constant work-rate exercise; the placebo and control groups did not show these changes. The perceived respiratory effort was unchanged in spite of the higher ventilation rate after training. CONCLUSIONS: The results suggest that respiratory muscle endurance training improves cycling performance in fit, experienced cyclists. The relative hyperventilation with no change in respiratory effort sensations suggest that respiratory muscle training allows subjects to tolerate the higher exercise ventilatory response without more dyspnea. Whether or not this can explain the enhanced performance is unknown.
Thought this was interesting (and a bit weird). Reminiscent of Zapotek, who reportedly did exactly this type of training.
The breath-hold training program did not modify the maximal performances measured during an incremental cycling exercise.
I don't have access to the full article so I'm not sure how to interpret the phrase "maximul performances measured during an incremental cycling exercise" -- not sure what they measured, or for how long.
[the inspiratory muscle training group] completed the simulated 20 and 40 km time-trials faster than the placebo group [66 +/- 30 and 115 +/- 38 s (3.8 +/- 1.7% and 4.6 +/- 1.9%) faster respectively
Almost 2 minutes advantage for a 40k time trial is no small amount!
I understand now the marketers claim the benefits now relate to stronger and conditioned breathing muscles requiring less oxygen rather than increased breathing efficiencies. This saving is diverted to other working muscles.
I read in one physiology textbook that a test in a number of cycling subjects showed that in elite cyclists ventilatory capacity may (at least in this case) be a limiting factor. Ventilatory capacity otherwise didn't limit performance in non-elite cyclists. I know in my case my legs go way before my lungs or heart rate are factors.
