True!.

Doesn’t mean we shouldn’t bend forward though.

I’m not a massive fan of sit ups and similar exercises at JSPROFITNESS. They can be used as part of a balanced programme, but most people do too much abdominal isolation work and not enough core stability work and functional exercises.

Also, if you have a weak back, rather than avoid bending it, I would recommend that you have these problems addressed as much as possible by seeing a Corrective Exercise Specialist who can give you appropriate exercises, loads, repetitions, etc to improve the situation.