Strength Challenge 20.20 is the challenge to gain as much strength as possible within the time limits of two 20 minute workouts per week. The book does not claim that the best way to reach your maximum potential for strength gains is to work out twice per week for just 20 minutes, but it is certainly possible to gain a substantial amount of strength within the confines of two 20 minute workouts per week. If you only have a small amount of time to work out each week and want to get the most out of your training, the information in Strength Challenge 20/20 is designed with you in mind. Strength Challenge 20/20 can be accessed for free in PDF format; all you need to do is click on the book cover. Best of training to you.