You want great legs and abs, right? Well, here's a new challenge to try. This does not absolve you of your jumping jacks though! You're still expected to get that 6000 done. I have tried this and boy... that 5 times is a killer.
For full details on the challenge, to check how others are doing, and to view other amazing challenges, check out the challenge on the TribeSports website.
Cheers Eights & Weights!