Good job, mate! Congratulations!

o1d one is right. WOB does respond to practice, so don't be shy about flinging that thing over a tree branch in the park.

If you're going to spend some gym time, then think about doing hang cleans and dumbell snatches to help with WOB. Dead lifts, quickly, are good, and if dead lifts mess with your lower back then look up "suitcase dead lifts" on YouTube and try those. Try doing exercises that make you stand up quickly with heavy-ish, but moderate weight. Pushing for personal max in the weight room is probably not what you want to be doing at this point in the season, but moving lighter weights FAST is absolutely A-OK.