Abdominal surgery through a midline incision is performed in most cases of colorectal cancer (CRC).Abdominal wall function in terms of abdominal muscle strength and occurrence of incisional hernia may be affected postoperatively.The objective of this study was to evaluate variations in trunk flexion strength (TFS) following abdominal surgery, and explore the correlation between TFS and the scar length in CRC patients.Significant pre-postopemtive differences in TFS were observed.