Get Fit With Mel B
51 Achievements
PS3
20 Run
Done 20 good reps in a row
71.2%
How to unlock the 20 Run achievement in Get Fit With Mel B - Definitive Guide
Key here is the word "Good" and not Perfect - you might get the Perfect 10 achievement if you can ten perfects in a row by going for this. I picked this up in my first workout first try so I can't see it being too hard for anyone.