Grip training/ Core conditioning

Find a "bipod swingset" at a playground, the taller, the better. They have only 2 supports in the ground that meet at the top- Image.

Sit on the ground and climb up one side of the support poles, once at the top, reach for the other, climb back down the other side. Reverse the process and you've done 1 repetition.

Beginner challenge-

Do 10 repetitions, resting as needed.

Intermediate Challenge-

Do 3 sets of 5 repetitions, resting only after all 5 are complete (don't touch the ground half way through a rep)

Advanced Challenge-

Do 2 sets of 10 repetitions, touching the ground to rest only between sets.