Comparison of Calf Muscle Strength and Endurance among smokers and Non Smokers

This observational, cross-sectional study aims to compare calf muscle strength and endurance between smokers and non-smokers aged 20–50 years using the Single-Leg Heel Raise Test. Conducted at SDM College of Physiotherapy, Dharwad, the study will include 60 participants divided into two groups: smokers (with at least 1 year of daily smoking and a minimum of 5 pack-years) and non-smokers (no history of smoking or passive exposure). Individuals with respiratory, neuromuscular, cardiovascular, metabolic disorders, or recent lower limb injuries will be excluded. The primary outcome is the number of correct heel raises performed until the participant is exhausted. The test will be stopped when participants are unable to (1) raise the stance heel from the incline or repeat a full heel-rise cycle, (2) keep the pace, knee angle, or trunk position constant, or (3) use the wall to help with performance and rely on fingertip support for balance. Secondary analysis will explore correlations between smoking exposure (duration, intensity, pack-years) and muscle function. Data will be analyzed using independent t-tests and correlation statistics, with ethical approval to be obtained prior to the study.