This study aimed to investigate the effect of double oscillation exercise combined with elastic band exercise on the strength and thickness ratio of the scapular stabilizing muscles in healthy young individuals. A total of 30 subjects (17 male, 13 female) were randomly assigned to an elastic band exercise group (EBG) (n = 15) or an elastic band plus double oscillation exercise group (EB-DOG) (n = 15). A total of 28 subjects completed the experiment and evaluation. Patients in the EBG performed the elastic band exercise for shoulder flexion, extension, abduction, adduction, horizontal abduction/adduction, and internal/external rotation for 30 minutes/session, five times/week, for four weeks. Patients in the EB-DOG performed the elastic band exercise for 15 minutes and the double oscillation exercise in three planes of motion (frontal, sagittal, and transverse), using a Bodyblade® for 15 minutes/session, five times/week, for four weeks. Shoulder muscle strength was assessed using a manual muscle test device during maximal voluntary isometric contraction (MVIC), while the thicknesses of the scapular stabilizing muscles were assessed using rehabilitative ultrasound imaging both at rest and during MVIC. Both groups had significant effects on shoulder muscle strength, however, there was no significant difference between the two groups for change value of shoulder muscle strength (Bonferroni correction p < 0.005). Significant differences were observed in the group × time interactions for horizontal abduction, external rotation, and protraction. There was a statistically significant improvement in thickness ratio of LT and SA in the EB-DOG and no significant difference was founded in EBG (Bonferroni correction p < 0.006). In comparison between the two groups, EB-DOG showed a significant change in the thickness ratio of LT compared to EBG. In addition, significant differences were observed for the group × time interactions for the thickness ratio of the LT (F = 12.177, P = 0.002; Bonferroni correction p < 0.006). The double oscillation exercise combined with elastic band exercise more effectively increased the thickness of the shoulder stabilizing muscles compared with the resistance exercise alone.