That Ronda Rousey vid is cool. I've long warmed up with a bit of PVC pipe, although if I attempted that I'd be face down on the floor in short order.
I think it's possible to 'do a lot of things at once' but it's something that needs to be eased into at a very gradual rate.
With karate and volleyball on hiatus for a while, this may actually be a good opportunity for you...
First of all, if we consider what we do as training, everything should be planned, and dare I say, periodized. I remember Ed Coan saying how he planned his bicep curls for the 12 week cycle beforehand. Or close to it. Every exercise in the program was expected to progress. I guess the case in point is that if an exercise is worth doing, it's worth doing up to the standard.
However, I do agree that it's worthwhile to concentrate on different things in different times. How to exactly go at it is the question.
The conventional wisdom has typically been that athletes who see the weightroom as accessory to a sport typically focus on it in the off season and then maintain through the season. However, from what I've read lately it seems that the most successful strength coaches go at it differently. The weights go heavier and heavier as the season gets tougher and tougher, only the volume of the lifting is cut down. One could almost consider it a very long linear powerlifting cycle.
Continuing on that track, I have also always felt that volume is the factor that drives me down, not intensity. That's also typically against the popular thought.
Very good point - periodization works, that's what the guys who are real students of this stuff do. And this is something that I'm not very good at planning.
Lately I've just been relying on randomization to do the periodization for me - a lot of what I do is determined by coin flips and dice rolls. Which I think works well enough if you're not peaking for something, but it's seems that it's largely about accumulating volume - it doesn't have the same aspect of progressive overload and deload as a more traditional lifting cycle. Perhaps I need to think more about adding those aspects in some form.
That's definitely what we did when I was throwing the discus back in college. A lot of volume during the off season, and the volume would drop off when the season started, but we'd still push intensity. We had two scheduled 1RM testing times; once at the end of off-season training and once maybe a month or so before the end of the season - after which we'd be tapering ahead of the final meets. The in-season test was consistently higher than the off-season test. And we didn't feel "beat up" - always felt pretty fresh for the final meets.
That seems consistent with your observation - volume might be more taxing than intensity.
Your discus experience sounds great. I hope it becomes common knowledge in every sport.