Will Craniocervical Flexion Exercise with Pressure Biofeedback Unit Actually Increase the Strength of the Deep Cervical Flexor?

Background Cranio-cervical flexion test (CCFT) with a pressure biofeedback unit (PBU) can enhance deep cervical flexors (DCF) activity. However, its efficacy in strengthening DCF muscle remains uncertain. Objectives We evaluated the effectiveness of Cranio-cervical flexion exercise (CCFE) with PBU in strengthening DCF in healthy adults. Methods In total, 24 healthy adults without neck pain were included. DCF strength was measured using a load cell during CCFE with PBU. DCF strength was measured using a load cell during CCFE with PBU in supine position. Pressure was progressively increased from 20 to 30 mmHg in 2 mmHg increments; notably, maximum strength was recorded. At each pressure level, isometric DCF strength was measured 3 times for 5 s with 10 s of rest between each measurement. Subsequently, Correlations between the normalized DCF strength and normalized percentage of the pressure during the CCFT were determined by using Pearson's correlation coefficient. Results The primary outcome measure was increased DCF strength with increasing pressure. In addition, the ratio of muscle strength at each pressure to maximum strength demonstrated a significant increase. Conclusions CCFE with PBU is an effective intervention for strengthening DCF muscles in healthy adults. Furthermore, load cells can measure DCF strength and guide exercise programs for targeted strengthening.