i like to do planks, squats, jump squats, bicep curls, mountain climbers, sit ups, bicycle crunches, and rows.
Plank !every morning try to keep the position a Little bit longer. You will See the results very quickly .
Do the plank challenge! Look it up on google images and there will be a calendar. Also, no stirrups!
I did MMA for years and it helped my core, back, and legs enormously- kickboxing and jiujitsu would probably have the same benefits. Yoga is helpful as well (I need to start doing that again...), as is just plain old stretching.
Do pole work on the circle
In all honesty yoga, I never really thought it would help when I started but now everything has just become easier when riding
One set of workouts that allow riders to do total body work outs without using weights (something they can do at home or even at the barn) would be start at 2 reps and 2 sets and increase as your strength does.
Legs - Squat.
Chest - Push up.
Back - Burpees.
Lower Back - Hyperextension.
Tricep - Dips.
Bicep - Chin-Up.
Calves - Calf Press.
Ab - Cable Crunches.
Hope that helps!