After weeks one and two, I'd say so far, so eh. Going into week three, I thought that Jen Selter could do better and push her work-out challenge even further. The end of week two was definitely a step up from week one, though, so I went into week three with high hopes.

Day 15

I started with Selter's week three warm-up, which is a slightly more advanced version of the set for weeks one and two. The new warm-up consists of 30 jumping jacks, 15 squats, 10 lunge jumps, high knees for one minute, then repeat.

After the warm-up, the day's workout is split into four parts. Jen asks that you set a timer for five minutes, complete as many rounds as possible, take a two minute break, and then move onto the next set. I really liked this workout because its variety kept me interested, and the whole thing, including warm-up and stretching, took about 45 minutes.

Part A: 10 push-ups, 20 squats.

Part B: 10 burpees, 20 sit-ups.

Part C: 30-second plank (w/ hip rotations), 20 jumping lunges. 

Part D: 10 tuck jumps, 20 squat jumps, 5 push-ups.

Do whatever you can in the time allotted, and don't be afraid to push yourself. This is a pretty customizable workout in terms of effort, but that doesn't mean you should slack off either if you're looking for results.

Day 16

This seemed like one of the more daunting workouts at first, but it ended up being pretty manageable. Selter provides you with a large number of reps for a few different exercises. The purpose of this is to allow you to break it up any way you'd like, so that the workout is whatever works best for you.

Selter's list for Day 16 goes like this: 50 Burpees, 100 step-ups (both legs), 150 sit-ups, 200 air squats and 250 jump ropes (real or imaginary). Once you split it up into shorter sets, this doesn't feel so overwhelming. Jen asks you to set a timer for 20 minutes and get through as much as you can, but you can also just take as much time as you need to finish it all.

I split the reps into five sets and got through four of them in the 20-minute timeframe. My sets included 10 burpees, 20 step-ups (each leg), 30 sit-ups, 40 air squats, and 50 jump ropes. If I had more time, I would've liked to make it through the entire workout, but I only had about half an hour to spare, so I stuck with the 20 minutes plus warm-up and stretching.

Day 17

Cardio day—aka back to the ArcTrainer once more.

Day 18

Today, I was low on motivation, but I'm not a quitter. The exercise was called the "Dirty 30 for 300," which consists of 10 exercises—30 reps of each. The ten exercises include jumping lunges, jumping jacks, push-ups, mountain climbers, alternating bicep curls (I used 15 pounds), tricep dips, step-ups, jumping air squats, burpees and sit-ups.

Selter wants you to complete the week three warm-up, set a 25-minute timer, and go through as many sets of the dirty 30 as you can in that timeframe. Her timing for this one is spot on because it pretty much took me the full 25 minutes to complete one set.

Day 19

Day 19's workout seemed pretty odd to me. The exercises themselves weren't super easy, but they weren't that challenging either. This, combined with a short timeframe meant that I didn't really feel like I had pushed myself, and at this point in the challenge, I wanted to feel like I was working pretty hard.

As usual, you complete the week three warm-up first. Next, Jen has you complete Part A and then finish your work out with Part B, which is just a one minute step-up, step-down plank. Part A consisted of setting a 15-minute timer and completing as many sets as possible. I was able to finish 3 sets of 25 crunches, 15 donkey kicks (each leg), 25 walking lunges, 15 squat jumps, 30-second plank and a 30-second side plank on each side.

Day 20

I left Saturday to be my rest day. My body was feeling pretty good—a little sore considering I had worked out for six days straight, but not so sore that I was uncomfortable during the day. I'm still not sure how I feel about that because I enjoy feeling worn out on a rest day. Even on a day meant for recuperating, I want to feel like I deserve the day off.

Day 21

I finished off the week with a second cardio day. Cardio is always a comforting workout plan for me to fall back on when Jen doesn't have a specific set of exercises for the day. The sweat and full body exertion that it demands gives me a little taste of how I used to feel playing varsity sports in high school—something that I miss in the midst of injuries and a crazy college schedule.

After all of week three, I'm still not the biggest fan of the Jen Selter challenge. There are definitely some workouts in the past two weeks that I enjoyed and felt the benefits of, and I don't want to discount that. Unfortunately, however, of the 12 of Selter's strength workouts that I've completed so far, I'd probably only carry 4-5 of them into my usual workout routine after this challenge—and I'd also want to extend the timeframe on most of them.

That said, there's still one week of Selter's challenge to go—so, here goes nothing.