Smoking is a major public health concern, significantly affecting lung function and overall respiratory health. Heavy smoking leads to chronic obstructive pulmonary disease (COPD), emphysema, and a decline in lung capacity. Exercise interventions, particularly those targeting the trunk muscles; have demonstrated potential in improving respiratory function. Trunk muscle strength is essential for optimal breathing mechanics, as these muscles support the chest wall and aid in the expansion and contraction of the lungs. There are two primary types of muscle strength training: isometric and isotonic. Isometric exercises involve static contractions where the muscle length does not change, while isotonic exercises involve dynamic movements with muscle lengthening and shortening. Each type of training offers unique benefits and impacts on muscle strength and endurance. This proposal aims to compare the effects of isometric versus isotonic trunk muscle strength training on lung function among heavy smokers, providing insights into their relative efficacy in improving respiratory health. Thus, the objective of this study was to explore the therapeutic effectiveness of Isometric versus Isotonic Trunk Muscle Strength Training on Lung Function in Heavy Smokers.