[Purpose] This study examined the effects of closed chain exercises performed with local
vibration applied to an unstable support surface on the thickness and length of the
transverse abdominis. [Subjects] The subjects were 64 healthy university students who were
randomly assigned to a bridge exercise with sling and vibration group (BESVG, n=30) and a
bridge exercise with sling group (BESG, n=34). [Methods] The bridge exercise was repeated
four times per set and a total of 18 sets were performed: 9 sets in a supine position and
9 sets in a prone position. In both the BESVG and the BESG groups, the thickness and
length of the transverse abdominis (TrA) were measured using ultrasonography with the
abdomen “drawn-in” and the pressure of a biofeedback unit maintained at 40 mmHg, both
before and after the intervention. [Results] In intra-group comparisons, the BESVG showed
significant increases in the thickness of the TrA and significant decreases in the length
of the TrA. The BESG showed significant increases in the thickness of the TrA. The BESVG
showed significant increases in the thickness of the TrA and significant decreases in the
length of the TrA compared to BESG. [Conclusion] Closed chain exercises for the lumbar
region performed with local vibration applied to slings, which are unstable support
surfaces, are an effective intervention for altering the thickness and length of the
TrA.