Isometric Versus Isotonic Trunk Muscle Strength Training on Lung Function in Heavy Smokers

Smoking is the practice of inhaling and exhaling smoke from burning plant material, most commonly tobacco, which contains the addictive substance nicotine. It is a major public health concern and the leading preventable cause of death and disease, as it damages nearly every organ and significantly increases the risk for many conditions like various cancers, heart disease, stroke, and respiratory diseases such as COPD. Quitting smoking can reverse many of these effects.

Smoking has long been identified as a major risk factor for a variety of health issues, and its impact on physical fitness and muscle power is an area of growing concern. Trunk muscle power, which is crucial for maintaining posture, stability, and overall functional movement, can be significantly affected by smoking. The primary mechanism through which smoking influences trunk muscle power lies in its detrimental effects on cardiovascular health and respiratory function. Nicotine and other harmful substances in cigarettes reduce oxygen supply to muscles, impairing their ability to generate power efficiently. This reduction in oxygen availability not only affects muscle endurance but also increases fatigue, hindering the muscle's capacity to function effectively during physical activities.

Moreover, smoking contributes to systemic inflammation and oxidative stress, both of which can compromise muscle health. Chronic inflammation can lead to muscle wasting and weaken the structural integrity of muscle fibers, including those of the trunk muscles. Oxidative stress, resulting from an imbalance between the production of free radicals and the body's ability to counteract their harmful effects, accelerates muscle degradation and impairs muscle recovery post-exercise. This is particularly detrimental to trunk muscles, which are constantly engaged in stabilizing and supporting the body. The cumulative effect of these processes results in diminished muscle power and functional capacity, ultimately affecting an individual's quality of life and ability to perform daily activities.

In addition, smoking is often associated with a sedentary lifestyle, which further exacerbates the decline in trunk muscle power. Smokers may experience reduced motivation to engage in physical exercise due to decreased lung capacity and higher perceived exertion during activities. This lack of exercise contributes to muscle atrophy and a loss of muscle strength and power. Thus, the combination of smoking-induced physiological changes and lifestyle factors creates a cycle of declining muscle power. Addressing smoking cessation and promoting physical activity can therefore be vital strategies in preserving trunk muscle power and overall health, highlighting the importance of integrating health education and smoking cessation programs in health curricula.

Inclusion criteria

• Individuals aged 20-45 years
• Self-reported heavy smokers (defined as smoking ≥20 cigarettes per day
• No participation in structured exercise programs in the past 6 months
• Capable of performing physical exercises

Exclusion criteria

• Diagnosed respiratory conditions other than smoking-related diseases (e.g., asthma)
• Cardiovascular diseases prohibiting physical exercise
• Recent surgeries or injuries affecting the trunk muscles
• Pregnant women