Iris Prismatica 23.6.2017 | 02:24http://www.livestrong.com/article/366815-are-v-ups-a-good-abdominal-exercise/http://www.menshealth.com/fitness/why-crunches-situp-are-bad-for-your-backhttps://www.earlytorise.com/10-ineffective-or-dangerous-exercises-to-stop/