My leg strength and cycling endurance have been improving lately, but now I find I'm feeling muscle (?) soreness in the groin and lower back. I think it's time to start core exercising and I have been searching and reading many of the related posts on the T&N Forum. Most of the off site referrals show many exercises for the core and for reasons of time I would like to narrow them down to as few as possible and make them somewhat cycling specific. I'm not trying to get a six pack or become Joe Weider, just something that makes my daily life and cycling an improvement.
Two exercises I've been thinking about are:
1. situps (or crunches or whatever),
2. and the plank.
Would this be enough for adequate core strength improvement or am I leaving out muscle groups that are important? I read the Bicycling.com article on core exercises, but 8 exercises seems like a lot to me.