I have this situps bench that can be flat, or at an incline. My question is, am i losing anything by only doing inclined situps? they seem more difficult/ strenuous as my abs are more sore after working them so im guessing they are better? also anybody have any tips on how to not make my head tilt forward, i can keep it straight on the flat regular situps but the incline makes it areal hassle. thanks for the help.