This study investigates the effectiveness of Inverse Ratio Breathing (IRB), a technique that adjusts the inspiration-to-expiration ratio to 2:1, in improving respiratory mechanics and functional capacity in women recovering from a modified radical mastectomy. The goal is to compare IRB combined with standard physical therapy to physical therapy alone to determine its potential as a rehabilitation strategy for post-mastectomy complications. Post-mastectomy complications often impair breathing and functional capacity. Conventional breathing exercises improve chest expansion but may have limitations. The objective of the study is to assess whether IRB enhances chest expansion and functional capacity more effectively than conventional methods. 66 women post-mastectomy divided into two groups:Group A: IRB + physical therapy and Group B: Physical therapy only. Inclusion criteria is post-mastectomy women referred for physiotherapy and patient with the history of cardiovascular/respiratory diseases or psychological issues will be excluded. Pre-assessment Thoracic expansion measurements for chest mobility  and 6-Minute Walk Test (6MWT) for functional capacity will be examine on POD -3 and post assessment  on POD- 8. Specific exercises will be deliver according to group allocation.