Stop The Pain: Why Your Neck And Back Hurt After Ab TrainingNeck tension and low-back discomfort after abdominal workouts usually mean the crunch is loading the wrong structures. A practical correction: place one hand on the lower abdomen and the other on the lower ribs. Error 2: Flattening the lower back too hardPressing the lumbar spine forcefully into the floor often tucks the pelvis excessively. Therapeutic exercise instructor Andrey Solovyov notes that the lumbar spine should keep its natural, slight curve and the weight should rest on the center of the sacrum. If neck strain, low-back pain, or abdominal doming appear despite these cues, the exercise has exceeded the current capacity of the deep stabilizers.