## 3 Results
### Directly Measured Physical Activity  
The heart rate data were collected from 21 participants--177,266 s of OPA and 162,694 s of physical activity outside work were considered for the analysis. Each participant's directly measured heart rate data corresponding to OPA were adjusted to five working days of eight hours shifts per week. The heart rate data corresponding to physical activity outside of work was adjusted to seven days per week and eight hours per day. The median number of moderate and vigorous OPA minutes per week corresponded to 415 and 21 min, respectively. The median moderate and vigorous physical activity outside work was 257 and 10 min per week, respectively (Table 5). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Activity**} & \multicolumn{8}{c}{**Difficulty Level**} \\ \cline{2-10}  & \multicolumn{2}{c}{**None**} & \multicolumn{2}{c}{**Mild**} & \multicolumn{2}{c}{**Moderate**} & \multicolumn{2}{c}{**Severe**} & \multicolumn{2}{c}{**Unable to Do**} \\ \cline{2-10}  & \(n\) & \% & \(n\) & \% & \(n\) & \% & \(n\) & \% & \(n\) & \% \\ \hline Perform hefty household chores (for example, washing walls or washing floors) & 6 & 60 & 2 & 20 & 1 & 10 & - & - & - & - \\ Carry a shopping sack or basket/briefcase & 8 & 80 & 2 & 20 & - & - & - & - & - & - \\ Recreational activities that comprise some force or impact through your hands, arms, or shoulders & 5 & 50 & 3 & 30 & 2 & 20 & - & - & - & - \\ (for example, golf, hammering, or tennis) & 6 & 60 & 4 & 40 & - & - & - & - & - & - \\ Stand for one hour or more & 6 & 60 & 4 & 40 & - & - & - & - & - & - \\ Reach for an object on an overhead shelf & 6 & 60 & 4 & 40 & - & - & - & - & - & - \\ Put on your shoes or socks & 5 & 50 & 3 & 30 & 2 & 20 & - & - & - & - \\ Get in or out of a car & 5 & 50 & 4 & 40 & 1 & 10 & - & - & - & - \\ Stoop or bend towards the floor & 5 & 50 & 4 & 40 & 1 & 10 & - & - & - & - \\ Kneel or squat & 5 & 50 & 4 & 40 & 1 & 10 & - & - & - & - \\ Use any handheld tool or equipment (some examples include a telephone, pen, keyboard, computer mouse, drill, hairdryer, or sander) & 6 & 60 & 4 & 40 & - & - & - & - & - & - \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Functional limitations to perform activities of daily living (ADLs) among construction workers who reported musculoskeletal pain in the last 7 days (\(n=10\)). \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{1}{c}{**Physical Activity**} & \multicolumn{1}{c}{**Median**} & \multicolumn{1}{c}{**Range**} \\ \hline Occupational physical activity (OPA) & & & \\ Heart rate/min & 94 & 48–192 \\ Sedentary, min/week & 357 & 1–930 \\ Light, min/week & 1429 & 303–1839 \\ Moderate, min/week & 415 & 37–1280 \\ Vigorous, min/week & 21 & 0–897 \\ High, min/week & 0 & 0–7 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Median heart rate and minutes of directly measured occupational physical activity and physical activity outside of work during a week (\(n=21\)). The Spearman correlation between moderate levels of OPA and BMI, Borg (RPE), self-reported minutes of moderate OPA, smoking status, and years of work showed a negative correlation for BMI (\(r_{s}=-0.4\)), smoking (\(r_{s}=-0.5\)), and years of work (\(r_{s}=-0.2\)). A positive correlation was found with Borg ratings of perceived exertion (\(r_{s}=0.1\)) and self-reported minutes of moderate OPA (\(r_{s}=0.2\)). No statistically significant associations were found (Table 6). A multiple regression model was run to assess the relationship between directly measured minutes of moderate OPA per week and the variables BMI, Borg's ratings of perceived exertion (RPE), self-reported minutes of moderate OPA per week, smoking status, and years of work in the construction industry (Table 7). The model indicated a direct relationship between minutes of moderate OPA per week and the Borg RPE. For one unit increase in the score, there was expected an increase of 55 min in the total number of minutes of moderate OPA per week.