Investigating the Relationships Between Body Composition, Peripheral Muscle Strength, and Cough Force in Healthy Young Adults

Introduction: Body mass index (BMI) is a key parameter used for obesity classification and the evaluation and monitoring of individuals' health status. Obesity, described by the World Health Organization as a major global epidemic, remains one of the most significant preventable and manageable conditions contributing to increased risks of cardiovascular and metabolic diseases. In addition to BMI, anthropometric measurements such as the waist-to-hip ratio are crucial indicators for risk assessment. While numerous studies in the literature have addressed the detrimental effects of obesity on respiratory functions, no study has specifically examined the relationship between cough strength-a vital respiratory parameter that reflects expiratory muscle strength- and body composition, waist-to-hip ratio, and peripheral muscle strength. Furthermore, although several studies have investigated the association between grip strength-a recognized indicator of peripheral muscle function in healthy individuals-and cough strength, no research to date has explored the relationship between pinch grip strength and cough strength.

Objective: This study aims to investigate the relationships among body composition, waist-to-hip ratio, peripheral muscle strength, and cough strength in healthy young adults.

Methods: This study was designed as a cross-sectional analysis. After providing detailed information about the study to potential participants, written informed consent will be obtained in duplicate from those who agree to participate. Following the completion of a general assessment form that captures demographic characteristics, each participant's height will be measured using a measuring tape. Body composition parameters-including body weight, BMI, body fat percentage, total body water percentage, muscle mass, basal metabolic rate, and metabolic age-will be assessed using a bioelectrical impedance analysis device (Tanita) available at our faculty.

Waist and hip circumferences will be measured and used to calculate the waist-to-hip ratio for each participant. Peripheral muscle strength will be assessed using a hydraulic hand dynamometer and a pinch meter, while cough strength will be evaluated using a peak cough expiratory flow meter (PEF meter). All measurements will be repeated three times, with the best result recorded for analysis. Results: Statistical analysis will be performed using IBM SPSS Statistics version 30 (SPSS Inc., Chicago, IL, USA). Normality of continuous variables will be assessed through normality tests, coefficient of variation, and graphical representations (e.g., histograms, detrended plots). Descriptive statistics will be presented as mean ± standard deviation for normally distributed variables, and as median and interquartile range for non-normally distributed variables. Categorical variables will be expressed as percentages (%). Pearson correlation analysis will be used for normally distributed variables, and Spearman correlation analysis for non-normally distributed ones. The appropriate correlation coefficients and p-values will be reported. A p-value of \<0.05 will be considered statistically significant.

Discussion: Interpretation will be based on the results of the statistical analyses.