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Trapezius muscle activity and body movement at the beginning and the end of a workday and during the lunch period in female office employees

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ABSTRACT

The aim of this study was to analyze the activity of the trapezius muscle and the arm acceleration during the course of a workday in office employees. It was examined if there are significant changes in trapezius muscle activity in the afternoon compared to the morning work period and relationships to the level of arm acceleration during lunchtime. Nineteen female office employees were recruited. A one hour period of the work in the morning, afternoon, and lunchtime were compared. The measures of the trapezius muscle activity and muscle rest time (TR) did not significantly differ between working in the morning (TR: median 10%; range 1%–49) or working in the afternoon (TR: median 18%; range 2%–34%). The 90th percentile of arm acceleration during lunch time significantly correlated with less trapezius muscle activity in the afternoon compared to the morning values (RT: Spearman R=0.80; p<0.01). Differences in the duration and level of trapezius muscle activity were bigger between the subjects than between different work periods or between lunchtime and work. Furthermore it seems that higher arm accelerations during lunch may be beneficial in reducing trapezius activity in the afternoon compared to the morning values.

No MeSH data available.


Values from the measures in the morning and in the late afternoon for the single subjects for a) the rest time of trapezius muscle, b) the 10th percentile of trapezius muscle activity, c) the rest time of arm acceleration, and d) the 10th percentile of arm acceleration.
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fig_002: Values from the measures in the morning and in the late afternoon for the single subjects for a) the rest time of trapezius muscle, b) the 10th percentile of trapezius muscle activity, c) the rest time of arm acceleration, and d) the 10th percentile of arm acceleration.

Mentions: EMG, heart rate, and arm acceleration were compared between the morning and the late afternoon. None of these parameters showed a significant difference between the two measurement periods (s. Table 2 and 3). Figure 2 shows selected parameters of the morning and late afternoon periods for the twelve single subjects.Table 2. Median and range during the morning period (MO), the lunch time (Lunch), the late afternoon period (LA), and the quotient late afternoon/morning (Quotient) for the parameters of trapezius muscle activity (EMG), the parameters of arm acceleration (ACC), and the heart rate (HR).ParameterMOLunchLAQuotientEMG, rest time10.0 (1.4/48.5)7.8 (3.0/41.5)18.0 (1.8/33.6)1.1 (0.3/3.8)EMG, 10th percentile4.9 (2.2/17.0)5.5 (2.0/11.3)4.3 (1.8/11.3)0.9 (0.4/3.3)EMG, 50th percentile22.4 (5.1/37.8)26.0 (5.9/47.5)17.5 (6.7/59.0)1.1 (0.4/1.9)EMG, 90th percentile61.6 (11.7/124.6)75.2 (37.4/113.5)72.0 (28.9/129.1)1.1 (0.6/3.1)ACC, rest time33.1 (13.1–48.2)25.0 (14.7/54.0)37.2 (6.3/54.7)1.0 (0.5/1.7)ACC, 10th percentile72.0 (70.0/82.0)73.0 (68.0/82.0)72.0 (70.0/102.0)1.0 (1.0/1.2)ACC, 90th percentile640 (277/1,105)983 (389/2,865)644 (322/1,454)1.0 (0.7/2.3)HR, 50th percentile75.0 (59.0/103.0)80.5 (58.0/96.0)75.0 (60.0/97.0)1.0 (0.9/1.1)Table 3. P values of the Wilcoxon test of the comparison between the measures from morning (MO) and late afternoon (LA), R values of the Spearman correlation (morning with late afternoon), and the amount of the variances explained by the time of the day (morning, lunch or late afternoon), by differences between the individuals and by their interactions (median and 95% confidence intervals determined by bootstrap analysis) for the parameters of trapezius muscle activity (EMG), the parameters of arm acceleration (ACC), and the heart rate (HR).Percentage of variance explained by differencesParameterP(MO-LA)R(MO-LA)between subjects [%]in time [%]Subject x time [%]EMG, rest time0.810.72**78% (54%/91%)1% (0%/10%)20% (9%/42%)EMG, 10th percentile0.160.67*73% (42%/88%)3% (0%/11%)24% (9%/53%)EMG, 50th percentile0.940.86***67% (41%/90%)2% (0%/16%)30% (9%/50%)EMG, 90th percentile0.330.70*82% (50%/94%)2% (0%/12%)15% (6%/41%)ACC, rest time0.720.2561% (25%/79%)4% (0%/25%)33% (19%/60%)ACC, 10th percentile0.330.4374% (54%/78%)2% (0%/17%)25% (17%/36%)ACC, 90th percentile0.750.5025% (16%/37%)23% (5%/43%)51% (32%/71%)HR, 50th percentile0.790.81**92% (82%/96%)1% (0%/6%)7% (4%/14%)Fig. 2.


Trapezius muscle activity and body movement at the beginning and the end of a workday and during the lunch period in female office employees
Values from the measures in the morning and in the late afternoon for the single subjects for a) the rest time of trapezius muscle, b) the 10th percentile of trapezius muscle activity, c) the rest time of arm acceleration, and d) the 10th percentile of arm acceleration.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383413&req=5

fig_002: Values from the measures in the morning and in the late afternoon for the single subjects for a) the rest time of trapezius muscle, b) the 10th percentile of trapezius muscle activity, c) the rest time of arm acceleration, and d) the 10th percentile of arm acceleration.
Mentions: EMG, heart rate, and arm acceleration were compared between the morning and the late afternoon. None of these parameters showed a significant difference between the two measurement periods (s. Table 2 and 3). Figure 2 shows selected parameters of the morning and late afternoon periods for the twelve single subjects.Table 2. Median and range during the morning period (MO), the lunch time (Lunch), the late afternoon period (LA), and the quotient late afternoon/morning (Quotient) for the parameters of trapezius muscle activity (EMG), the parameters of arm acceleration (ACC), and the heart rate (HR).ParameterMOLunchLAQuotientEMG, rest time10.0 (1.4/48.5)7.8 (3.0/41.5)18.0 (1.8/33.6)1.1 (0.3/3.8)EMG, 10th percentile4.9 (2.2/17.0)5.5 (2.0/11.3)4.3 (1.8/11.3)0.9 (0.4/3.3)EMG, 50th percentile22.4 (5.1/37.8)26.0 (5.9/47.5)17.5 (6.7/59.0)1.1 (0.4/1.9)EMG, 90th percentile61.6 (11.7/124.6)75.2 (37.4/113.5)72.0 (28.9/129.1)1.1 (0.6/3.1)ACC, rest time33.1 (13.1–48.2)25.0 (14.7/54.0)37.2 (6.3/54.7)1.0 (0.5/1.7)ACC, 10th percentile72.0 (70.0/82.0)73.0 (68.0/82.0)72.0 (70.0/102.0)1.0 (1.0/1.2)ACC, 90th percentile640 (277/1,105)983 (389/2,865)644 (322/1,454)1.0 (0.7/2.3)HR, 50th percentile75.0 (59.0/103.0)80.5 (58.0/96.0)75.0 (60.0/97.0)1.0 (0.9/1.1)Table 3. P values of the Wilcoxon test of the comparison between the measures from morning (MO) and late afternoon (LA), R values of the Spearman correlation (morning with late afternoon), and the amount of the variances explained by the time of the day (morning, lunch or late afternoon), by differences between the individuals and by their interactions (median and 95% confidence intervals determined by bootstrap analysis) for the parameters of trapezius muscle activity (EMG), the parameters of arm acceleration (ACC), and the heart rate (HR).Percentage of variance explained by differencesParameterP(MO-LA)R(MO-LA)between subjects [%]in time [%]Subject x time [%]EMG, rest time0.810.72**78% (54%/91%)1% (0%/10%)20% (9%/42%)EMG, 10th percentile0.160.67*73% (42%/88%)3% (0%/11%)24% (9%/53%)EMG, 50th percentile0.940.86***67% (41%/90%)2% (0%/16%)30% (9%/50%)EMG, 90th percentile0.330.70*82% (50%/94%)2% (0%/12%)15% (6%/41%)ACC, rest time0.720.2561% (25%/79%)4% (0%/25%)33% (19%/60%)ACC, 10th percentile0.330.4374% (54%/78%)2% (0%/17%)25% (17%/36%)ACC, 90th percentile0.750.5025% (16%/37%)23% (5%/43%)51% (32%/71%)HR, 50th percentile0.790.81**92% (82%/96%)1% (0%/6%)7% (4%/14%)Fig. 2.

View Article: PubMed Central - PubMed

ABSTRACT

The aim of this study was to analyze the activity of the trapezius muscle and the arm acceleration during the course of a workday in office employees. It was examined if there are significant changes in trapezius muscle activity in the afternoon compared to the morning work period and relationships to the level of arm acceleration during lunchtime. Nineteen female office employees were recruited. A one hour period of the work in the morning, afternoon, and lunchtime were compared. The measures of the trapezius muscle activity and muscle rest time (TR) did not significantly differ between working in the morning (TR: median 10%; range 1%–49) or working in the afternoon (TR: median 18%; range 2%–34%). The 90th percentile of arm acceleration during lunch time significantly correlated with less trapezius muscle activity in the afternoon compared to the morning values (RT: Spearman R=0.80; p<0.01). Differences in the duration and level of trapezius muscle activity were bigger between the subjects than between different work periods or between lunchtime and work. Furthermore it seems that higher arm accelerations during lunch may be beneficial in reducing trapezius activity in the afternoon compared to the morning values.

No MeSH data available.