Some enterprising person did a scientific experiment where they divided diabetic volunteers up into two groups. One group hiked uphill 3-5 times a week for a vertical rise of 600 meters. The other group hiked downhill the same distance. Both groups took a cable car the other way. A glucose tolerance test after two months showed a 9% average improvement for the group that hiked uphill and a 25% average improvement for the group that hiked downhill. The conclusion is that eccentric muscle work is more helpful for diabetes than concentric muscle work. I think it is an amusing scientific experiment.