Hiya,
Today I went for the Jeffing ratio 90:30 and I have to admit, apparently Jeffing works! The shorter I make my running ratio, the faster I run and the further I run. It is SO weird! I did go a little out of breath after a while, but it was more doable than with londer run ratios and after the run I still felt fresh and energized! Next time I am going for 60:30. My Runkeeper did bug a bit, making it very hard to hear when to do what. I ordered myself a Gymboss, but it will be 2 to 3 weeks before it is here.
Anyhow, here below are some stats, all for 30 minutes.
Ratio - km - pace
Straight run - 3,29 km - 6,4 km/h
5 min / 30 sec - 3,31 km - 6,6 km/h
2.5 min / 30 sec - 3,38 km - 6,8 km/h
90 sec / 30 sec - 3,47 km - 6,9 km/h
Cheerios, Evy