Quality Reps, NOT Quantity Reps!
Rep challenges and other types of high reps workouts are very popular ways of training. In addition, competition style workouts where you have a leader board and try to complete your reps in the fastest time are also very popular.
Unfortunately the fact is that these types of high volume, high reps workouts also have a higher risk of injury. Injuries happen most often when you are either excessively fatigued or you're not focusing. Both of these things things are far more likely when you're doing the last reps of an extremely high rep set of an exercise. You're far better off doing say, sets of 10 reps but doing them multiple times and limiting rest times. That way, you have a solid start for every set you do and are able to "pull in" as we sometimes refer to it. The bottom line is that training in this wasy is much better for maintaining proper form, breathing, and the other elements neccessary for a good rep in whatever exercise it may be.
In one of my old issues of Musclemag Internnational, there was an article written by Brad Steiner titled "Do You Do Will Power Reps?". He was explaining this exact difference between quality and quantity reps. All these years later, I have never forgotten that article and I constantly ask myself "Am I doing half-hearted reps or am I doing Will Power Reps?!
Watch the video to learn more about this.