This study aimed to evaluate the effects of ultrasound and adenosine 5'-monophosphate (AMP) treatments on the quality characteristics and tenderness of chicken wooden breast (CWB). Compared to normal breast, CWB exhibits distinct quality characteristics, including increased weight, higher pH, pale color, and a firmer texture. It was found that ultrasound, AMP, and their combined application significantly reduced the shear force of CWB (p <
0.05), effectively improving its tenderness. The combined treatment of ultrasound and AMP significantly decreased the filtering residues of myofibrillar proteins (MPs) and increased myofibrillar fragmentation index (p <
0.05). MPs structure analysis showed that the combined ultrasound and AMP treatment facilitated the degradation of tropomyosin, the transformation of α-helix into β-sheet, and decreased intensity of tryptophan fluorescence, promoting MPs degradation and improving CWB tenderness. Pathological analysis and scanning electron microscopy also observed muscle fiber damage and the loss of myofibrillar membrane integrity following the combined treatment. These findings highlight the potential of AMP and ultrasound treatments in the tenderization process of CWB.