When you focus on strength training you get strong. When you focus on conditioning you have endurance. It's hard to do both.
Soon after I was pressing the 28kg kettlebell, I switched my focus to conditioning type workouts. Not to say that I had become weak by any means, but I started having difficulty with pressing the 20-24kg kettlebell, boo! This was (and sometimes still is) a struggle for me. It seemed simple enough that I should be able to spread my focus in two directions.
Focus, however needs focus. It's similar to completing a task. If you get in your car to go to the grocery store and end up stopping off for a cup of coffee on the way, which is right next door to the car wash, which reminds you that you need an oil change, two hours later you have no time left to go to the grocery store.
Although I am still strong, it's been a struggle for me to be my strongest and still have what I consider to be decent conditioning. We're about ready to see if I can do it. The next 15 weeks of my training is already planned out. I'll be reporting back on it's progress often, I'm sure with successes and frustrations.