Positional and mechanical improvement:
Rotational/ lateral movement drills, lifts, and swings
At skill work weights and with the guidance of a qualified trainer, practice several movements listed above and make improvement in the details of each. Start with the basic variations of each and add difficulty as appropriate. Note: Never make the mental mistake of thinking you’re too advanced for skill work in any realm.
Then, 2 rounds of:
As many reps as possible are completed in one minute, switching arms evenly but as desired, and followed by an immediate transition into the plank position.
If we are arm-throwing the ball, as opposed to transferring power from the floor, through the hip, and into the arm last, the plank hold will be worse. Organize your position- both in the interest of power and efficiency.
And then, “Time under tension”:
One max-duration plank hold
Work to “True” failure (loss of physical positioning) not “Relative” failure (loss of mental endurance). If time reaches two minutes, you may stop if desired. If time is under two minutes, do it again, and accumulate at least two total minutes.
Do the work that improves the work; Mobility/ detailed positional improvements/ meticulous warm-ups may not be glamorous, but they are certainly more appealing than under-performing and/ or getting hurt due to ignoring them.