# Assessment of Musculoskeletalelal Loads among Office Workers Due to Predicted BMI Increase
## 4 Discussion
### Increased Risk of Injury and Musculoskeletal Disorders Due to Elevated Biomechanical Loads  
Given that standing and sit-to-stand maneuvers, with an average of 33 to 71 daily repetitions [12], are key elements of everyday activities for most people, this paper aimed to verify how the increase in body mass affects the functioning of the motor organ during these basic activities. It is expected that individuals with a higher BMI will experience greater loads on the lower segment of the spine during daily activities because excess body mass (fat) acts as an additional load. Numerous scientific studies have quantitatively determined the forces exerted on the lower back and intervertebral disks during the performance of everyday activities [27; 28; 30; 45; 46]. However, there are few studies focusing on the loading exerted on the lower segment of the backbone in individuals with a high BMI [8; 9; 10]. Our research, along with studies by [PERSON] et al. [9] and [PERSON] et al. [8], confirmed the hypothesis that changes in body mass affect the loads exerted on the backbone. [PERSON] et al. [9] investigated the effect of variations in body weight on spinal loads using a detailed biomechanical modeling approach. They found that spinal loads increased by up to 15% in individuals with significant obesity (BMI \(>\) 30 kg/m\({}^{2}\)). The projections presented in this work indicate that from 2015 (when the average global BMI was at the upper limit of the normal range) to 2050, the mean global BMI will increase by approximately 3 kg/m\({}^{2}\). The predicted BMI growth in the simulations performed will result in an 11% increase in loads at L5-S1. [PERSON] et al. [8], using a subject-specific trunk musculoskeletal model, showed that an increase in body weight from 55 to 120 kg nearly doubles the compression forces at the L4-L5 and L5-S1. The degree of increased spinal loads varies for different positions and activities. This work only compared standing and sitting down on a chair. It was observed that the resultant reaction force in the L5-S1 segment is 2.5-fold higher during the activity of sitting down compared to standing. [PERSON] et al. [9] demonstrated that load increases are greater for tasks performed in bent positions compared to upright positions. They found that with an increase in body mass from 51 to 119 kg, the compression at L5-S1 increased by 80-147% with unloaded hands and by 46-52% when holding an object in a bent trunk position. Both in [PERSON] et al. 's [9] research and the presented simulation results, compression forces are dominant compared to shear forces (Figure 3). [PERSON] et al. [8] also investigated the impact of various personal factors, such as age, gender, body height, and body mass, on spinal loading. Fluctuations in body mass had the greatest impact on lower back loading, followed by gender, with females experiencing slightly larger loads (\(\sim\)4.7% in compression and \(\sim\)8.7% in shear) than males. In this work, the simulations only involved BMI changes in males, but the region of residence was taken into consideration. The highest load increase was observed in the average Polish man, associated with the highest predicted BMI growth in the coming years (Figures 1 and 3). In the literature, spinal overloading is considered a risk factor for back pain [47; 48; 49]. In addition, comprehensive studies by [PERSON] et al. [10] confirm that a higher BMI is causally related to the risk of intervertebral disk degeneration, sciatic neuralgia, and low back pain. The tendency of the human body to accumulate and maintain fat tissue is a problematic health issue not only from the perspective of the lower spine. Among serious health issues in the working population, musculoskeletal disorders are one of the most frequent reasons for work absence and disability. [PERSON] et al. [7] point out that BMI is associated with musculoskeletal symptoms, particularly in the lower extremities.