Don't look forward or up; this strains the neck. Keep your eyes on the floor between your hands.
A clenched jaw and tightened throat restrict nasal breathing and promote shallow, upper-chest breaths. Planks require intra-abdominal pressure and steady oxygen flow — two things that suffer when you look like you’re holding in a scream. plank face
In a good plank, your cervical spine is neutral — ears aligned with shoulders, gaze slightly ahead of your hands. If you’re craning your neck or tucking your chin, your face will follow. Fix the neck, fix the face. Don't look forward or up; this strains the neck