September Already??? Plank Challenge

I am going to be brief here, but I can't believe it is already September.  I should have give you guys a little bit more advanced notice here on the plank challenge.  I did it back in June, while recovering from my crash and I must say that I was THRILLED with the results.  It was hard, but doable.  I got very shaky in the last minute or so each time I did it.  Since I had such great results, I haven't started it over, but I have tried to keep up with doing planks 3 or 4 days a week, for anywhere between 3 and 4 minutes at a time.  It is still a challenge, but I need to go back to doing them a bit more often and even longer now since I have built up a good plank base.  Some options that were given to me for starting over and making it harder are using a ball, bosu ball, or weights on my back.  I haven't tried any of those methods consistently with the plank challenge, but I think I will do the plank challenge again WITH my 3-4 minute planks several times a week.  Like do my 4 minute plank, take a rest, and then do the plank that goes with the day.  This challenge is set up for June, but it will work with any month as long as you just follow the date, and not the day of the week.  It is a super simple and quick way to add some strength training to your current regimen.  Really, who can't just take 1-5 minutes on any given day before bed or after work do get it done?  You still have to do the first day even though it is crossed out.  This was just when I saved it off the Team Aquaphor page so that I could have it on my computer and not constantly checking fb to find my workout.