Table 2. Exercise program for improvements of the deep cervical flexors.

	Items	Intensity & Repetitions
Warm up (10 min)	Stretching (the neck, shoulder and scapular muscles)
Conventional DCF exercise	Supine position & Sidelying position	RPE 11–13
	• Neck curl with chin tucked • Neck lateral bending with chin tucked (right & left)
	Sitting position
	• Chin tuck • Head pushing against the palm with chin tucked (all directions) • Neck bending on the diagonal with chin tucked (right & left)
PBU exercise		20–30 mmHg

• Experimental group: stretching (10 min) + Conventional DCF exercise (15–20 min, 10–16 reps × 1–2 sets) + PBU exercise (5–10 min, 10–16 reps × 1–2 sets). • Control group: stretching (10 min) + conventional DCF exercise (20–30 min, 10–16 reps × 1–4 sets)

DCF: deep cervical flexors, PBU: pressure biofeedback unit