jump ropes

Dunno, but the Everlast leather rope without weights is the best one around.

Sorry I couldn't answer YOUR question, but I did answer A question.

http://www.weightloss.com.au/Tools/EnergyCharts.htm

It's metric because it's from my country and we have kilo-everything.

We also call it "skipping" and not "jump rope" so that all might be a bit confusing but it's the best I can do at the moment.

What the heck, goodfielder. I've got a Kettler rowing machine calibrated in kilojoules und schlage/km.