I am working on my base miles for 2021 and I notice that my core is weak and my butt wants to slide forward on the saddle prompting my to need a reset every so often to get myself anchored rearward for more of a "power position".

As part of the adaptation phase and base mile building I have a similar situation with my weak arms - they quiver a bit but I find that if I can keep them engaged on the tops, hoods and drops while riding both seated and standing - have have better recovery with my lower body.

Excuse me if I am stating the obvious here, I just was wanting to prompt some conversation about early season adaptations that can make a difference at keeping you fresher on the bike. Consciously pushing myself back further on my butt requires a strong isometric contraction of the abs. This on and off contraction does pay off since I noticed my belly is getting flatter and stronger and my ability to not slide forward on the saddle so much has improved.

The same with the awareness of all the work that the arms are doing. I am trying to get more basic fitness in at the gym with some yoga moves and some basic pushups for strengthening the chest, shoulders and arms. I have found that while climbing out of the saddle my arms will fatigue and start to quiver which prompts me to sit down sooner. But if I can really grip the hoods and keep my arms in a rhythm while standing to climb, it seems that I can actually spin more smoothly and do some pulling up at the bottom of the pedal stroke in order to keep the bottoms of my feet from compressing so much. So again, here is another minor adaptation that "practice makes perfect" and the more it is successfully practiced, the fresher I am able to stay on some of the more challenging (faster, more climbing) solo and group rides.