I commute to my work by bicycle everyday except weekend 12.6 km and back (totalling 25.2). I cycle this route in low-intensity between 60%-70% MHR. I would like to add some abs exercises as my belly is a bit bigger than it should be. A friend of mine recommended me some excercises (crunches, leg raises, planking etc.). but I am a bit worried that this might be too much for a body to handle and I might hurt myself or stop losing weight/start gaining weight. I am not even sure if my standard commuting length is not too long and thus counter-productive.
Is it allright to combine cycling (considering the length) and abs exercises in one day?