I’m having trouble with sit-ups and crunches, instead of isolating my abs they seem to just be hurting my back. Might I be doing something wrong or may I have a back problem I’m not aware of.

There could be a million different things going on, see a PT or doctor or someone qualified to help.

Likely there is some rehab program, and some modifications you can make to abdominal exercises so they are no longer painful.

So yeah, seek the help of a professional.

Maybe You forgot to use a mat or smth...

Here is an article that might be of interest:

http://blog.newsweek.com/blogs/thehumanc...don-t-work.aspx

Hmm, it makes me wonder if sit-ups contributed to Bruce Lee’s nearly crippling back injury; let’s face it the man did a LOT of sit-ups.

But are these new ways of strenghtening abs that effective than sit-ups?

might seem a daft question, but are you bending your knees when you do sit-ups? Some folk still don't!

Is your pain only there when you are doing sit-ups or do you have pain other times. If its only when you do sit-up then you might be doing something wrong but if its other times also then see a doctor and find out the right way. The internet is a poor doctor and you will get a lot of cures some might work but some might make you worse I would not gamble with your back.

One question to ask yourself -- is there any soreness in your abdominals at all? Having muscle pain in the back but not in the abs region points to bad form.

Due to the origin of the primary hip flexors (psoas) on the lumber vertebrae, full sit ups actually place stress in excess of several times body weight on the anterior surfaces, and encourage posterior disc herniation. the best solution is to stop doing full sit ups and replace them with planks & crunches- also learn to identify thoracic spinal flexion during a crunch, as opposed to hip flexion (if the lower back comes off of the floor, your hip flexors are involved, taking the work off of the rectus abdominis and placing compressive loading on the lumbar spine). The first link below is most applicable, with the others being relevant to specific training actions:

http://fightsciencesresearchinstitute.wo...ack-or-hurting/

http://fightsciencesresearchinstitute.wo...ng-deep-stance/

http://fightsciencesresearchinstitute.wo...-combat-sports/

http://fightsciencesresearchinstitute.wo...ion-strageties/