# Backward Locomotion as a Novel Strategy for Enhancing Obesity Management
## 1 Introduction  
Obesity, defined by a body mass index (BMI) \(\geq\) 30 kg/m\({}^{2}\), is a critical global public health concern linked to elevated risks of Type 2 diabetes, cardiovascular diseases, and hypertension [1]. According to the World Health Organization (WHO), obesity accounts for 80% of Type 2 diabetes cases, 35% of ischemic heart disease cases, and 55% of hypertension cases in Europe, contributing to over 1 million deaths annually [2]. In Turkiye, the prevalence of obesity is notably high, with 20.2% of adults classified as obese in 2022, marking the highest rate in Europe [2,3]. The global economic burden of obesity is substantial, with annual costs estimated at USD 2 trillion, equivalent to 2.8% of global economic activity [4]. Effective obesity management, aiming for a 10% weight loss over six months, is essential to mitigate these health and economic impacts. Exercise, combined with energy restriction, is a cornerstone of obesity treatment; however, obese individuals often encounter physical and perceptual barriers to sustained physical activity [5]. Walking is a widely recommended low-impact exercise, but backward locomotion, which requires greater coordination, may provide distinct physiological benefits, such as increased cardiopulmonary demands and reduced joint stress compared to forward locomotion [6,7]. Despite these potential advantages, the acute effects of backward locomotion in obese individuals remain largely unexplored, representing a significant gap in the literature [8].  
This study aims to compare the acute cardiorespiratory, metabolic, and electromyography (EMG) responses of forward and backward locomotion in individuals with a BMI \(\geq\) 30 to inform the design of optimized exercise interventions for obesity management. Our primary hypotheses are: (1) backward locomotion will elicit significantly higher cardiorespiratory (e.g., oxygen consumption [VO\({}_{2}\)] or heart rate) and metabolic (e.g., energy expenditure or lactate levels) responses compared to forward locomotion; (2) backward locomotion will result in greater EMG activity in key lower-limb muscles (quadriceps, hamstrings, soleus, and tibialis anterior) due to increased coordination demands; and (3) backward locomotion will be perceived as more demanding, as measured by the Borg Rating of Perceived Exertion (RPE). Studies on backward locomotion in obese individuals are limited in the literature and have generally focused on long-term effects (e.g., body composition and cardiorespiratory fitness) or biomechanical parameters (e.g., joint loading) [6,8,9]. These studies have not comprehensively examined the acute cardiorespiratory, metabolic, and muscle activation responses of backward locomotion in the obese population. Our study provides a unique contribution by comparing the acute effects of forward and backward locomotion in sedentary male obese individuals with a BMI \(\geq\) 30, measuring VO\({}_{2}\), VCO\({}_{2}\), heart rate, energy expenditure, lactate, Borg RPE, and quadriceps, hamstring, soleus, and tibialis anterior EMG activities. Separating the effects of speed and direction with a Latin Square design and two-way ANOVA fills this gap in the literature. It provides practical recommendations for optimizing exercise programs for obese individuals.