## 4 Discussion  
This study aimed to characterize the presence of work-related acute and chronic musculoskeletal pain and the physical demands measured as the physical activity levels at work among a group of precast concrete construction workers. According to our knowledge, this is the first study addressing these topics in this working population. Our long-term goal is to design and implement an integrated intervention to improve workers' health in this group of workers. Our study's findings indicate that the precast concrete workers had a high prevalence of musculoskeletal pain (e.g., \(\sim\)60% with acute pain and \(\sim\)30% with chronic pain over the last 12 months). The most common body areas affected by acute pain were their lower back, knee, and shoulder. The areas most commonly affected by chronic pain were their lower back, knee, and shoulder. A number of participants (26%) received health assistance from medical professionals or took medications to manage their musculoskeletal pain in the last 12 months. Our study revealed that almost half of the participants had musculoskeletal pain during the previous seven days. Workers who experienced musculoskeletal pain in the last seven days reported mild functional limitations, such as standing for one hour or more, reaching for an object on an overhead shelf, getting in/out of a car, stooping/bending over, kneeling/squatting, and using a handheld tool/equipment. Precast concrete workers reported moderate limitations when performing recreational activities involving force or impact through their arm, shoulder, or hand and while putting on their shoes or socks. These findings are similar to the results from a previous study on a group of commercial construction workers who suffered acute and chronic pain at work that impaired them to perform their work and activities of daily living (ADLs) [20]. However, the prevalence of acute pain (86%) and the presence of pain in the last seven days (62%) were higher compared to this study. Previous studies reported a high prevalence of musculoskeletal disorders associated with pain and highly physically demanding tasks in the construction industry [39; 40]. It is noted that, in the current study, the participants overreported minutes at work of moderate physical activity (600 min) compared to directly measured minutes of moderate physical activity (415 min). A previous study identified that the increased physical demands of a task could result in an increased overreporting of its duration. Furthermore, self-reported physical activity at work may incorporate the effect of psychosocial and other cognitive characteristics of the job [41]. Our direct measures of OPA indicated that the precast construction workers achieved a significant amount of moderate minutes per week (415 min). This result was higher than the findings reported among a group of commercial construction workers in Massachusetts (243 min) [18]. As expected, the data collected in this study indicated that this group of precast concrete workers was getting plenty of moderate OPA. The median amount of minutes accrued of moderate OPA was above the recommended leisure time physical activity guidelines of 150 min per week [42]. High OPA levels have been related to an elevated risk of cardiovascular disease (CVD) and all-cause mortality [43]. However, physical fitness seems to work as a modifier of this association. The workers with high physical fitness conditions and physical work demands did not experience an increased risk for CVD mortality [43; 44]. The multiple linear regression model indicated that BMI, smoking, and years of work were negatively associated with directly measured moderate minutes of OPA. The smoking condition had the highest impact on the number of minutes of moderate OPA. Workers who smoke had a median reduction of 395 min in the number of minutes of moderate OPA. Smoking has been identified as a cause of lung cancer and cardiovascular and respiratory diseases [45].