The purpose of this study was to measure the mean peak mobilization forces to the cervical spine 3-5 with grade III and grade IV of posteroanterior (PA) mobilization. Asymptomatic 25 college subjects were participated in the trial and eligible physical therapists performed cervical mobilization. The mean peak mobilization force was measured during the PA mobilization with grade III and grade IV by attaching a flexible force transducer over the C3-C5 spinous process. Three cycles of PA mobilization were performed in each spine and the therapist took approximately 2.5s to complete mobilization. After applying the grade III mobilization to the C3-C5, 30 minutes later, the grade IV mobilization was applied to the same area again. There were no significant differences between C3, C4 and C5 during grade III as well as grade IV. Upon comparing the mean peak force of grade III with mean peak force of grade IV at the C3, C4 and C5 respectively, an insignificant difference was also observed. The mean peak mobilization force was 4.53±1.79 N at the C3, 5.10±1.91 N at the C4, and 5.17±2.63 N at the C5 during grade III force was applied. The mean peak mobilization force was 4.40±1.56 N at the C3, 5.53±2.01 N at the C4, and 5.38± 2.73 N at the C5 during grade IV force was applied. This study suggested that the mean peak force of the grade III and grade IV mobilization in the C3-C5 was similar each other, also there was no difference between mean peak force of grade III and grade IV on C3, C4 and C5.

INTRODUCTION
 METHODS
 RESULTS
 DISCUSSION
 CONCLUSIONS
 REFERENCES

• Ho Jung An(Dongnam Health University, Suwon)
• Seo Yoon Heo(Kyungbok University, Pochen,)
• Jung Hyun Choi(Namseoul University, Cheonan)
• Wan Suk Choi(International University of Korea, Republic of Korea)