590936 research-article2015
SJP0010.1177/1403494815590936M.D. Jakobsen et al.Physical exercise at the workplace reduces perceived physical exertion during healthcare work
Scandinavian Journal of Public Health, 1–8
Original Article
Physical exercise at the workplace reduces perceived physical exertion during healthcare work: cluster randomized controlled trial
Markus DUE Jakobsen1,2, Emil Sundstrup1,2, Mikkel Brandt1,3, Kenneth Jay1,2,4, Per Aagaard2 & Lars L. Andersen1 1National Research Centre for the Working Environment, Copenhagen, Denmark, 2Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, Denmark, 3Physical Activity and Human Performance group, SMI, Department of Health Science and Technology, Aalborg University, Denmark, and 4Electronics and Computer Science, Faculty of Physical and Applied Sciences, University of Southampton, Southampton, UK
Abstract Background:High physical exertion during work is a risk factor for musculoskeletal pain and long-term sickness absence. Physical exertion (RPE) reflects the balance between physical work demands and physical capacity of the individual. Thus, increasing the physical capacity through physical exercise may decrease physical exertion during work. This study investigates the effect of workplace-based versus home-based physical exercise on physical exertion during work (WRPE) among healthcare workers. Methods: 200 female healthcare workers (age: 42.0, body mass index: 24.1, average pain intensity: 3.1 on a scale of 0 to 10, average WRPE: 3.6 on a scale of 0 to 10) from 18 departments at three participating hospitals. Participants were randomly allocated at the cluster level to 10 weeks of: (1) workplace physical exercise (WORK) performed in groups during working hours for 5×10 minutes per week and up to five group-based coaching sessions on motivation for regular physical exercise, or (2) home-based physical exercise (HOME) performed during leisure time for 5×10 minutes per week. Physical exertion was assessed at baseline and at 10-week follow-up. Results: 2.2 (SD: 1.1) and 1.0 (SD: 1.2) training sessions were performed per week in WORK and HOME, respectively. Physical exertion was reduced more in WORK than HOME (p 160, diastolic BP > 100), (2) a medical history of serious cardiovascular diseases (e.g. chest pain during physical exercise, heart failure, myocardial infarction and stroke), (3) a medical history of life-threatening disease, or (4) current pregnancy. Seven workers were excluded due to contraindications detected during the baseline clinical examination: five due to high blood pressure and two due to blood clot incidence within the last 2 years. The overall flow of participant enrolment is depicted in Figure 1.
Screening quesonnaires sent n = 490 subjects Did not reply n = 176 subjects Replied to quesonnaire n = 314 subjects Declined to parcipate n = 39 subjects Interested in parcipang n = 275 subjects Did not meet eligibility criteria n = 22 subjects Invited for clinical examinaon n = 253 subjects
Randomization and blinding We randomly allocated the 18 departments (200 participants), using a computer-generated random numbers table (performed by a statistician), to receive either physical exercise at the workplace or at home. Participants at each department and their management were subsequently informed by e-mail about group allocation. All examiners were blinded to the group allocation at follow-up (i.e. post intervention) testing (December 2013 to January 2014), and participants carefully instructed not to reveal their particular intervention group. Baseline characteristics, physical exertion scores and exhaustion at the end of the workday of the two intervention groups are presented in Table I. Interventions Each cluster of participants was allocated to a 10-week intervention period of either performing physical exercise at the hospital or performing physical exercise at home. Both exercise groups were encouraged to perform physical exercises for 5 × 10 minutes a week. The specific intervention protocols have been described in detail elsewhere [16] and are briefly summarized below. Workplace physical exercise (WORK) Participants randomized to physical exercise at their workplace (WORK) (n=111 subjects, n=9 clusters) performed group-based and supervised high-intensity strength training using elastic bands (TheraBand®) and kettlebells during working hours at the hospital. All training sessions took place in designated rooms located close to the respective departments. All sessions were supervised by an experienced
Did not show up for clinical examinaon n = 46 subjects Baseline examinaon n = 207 subjects Excluded due to contraindicaons n = 7 subjects Cluster randomizaon n = 200 subjects, n = 18 clusters
Physical exercise at the hospital (WORK) n = 111 subjects, n = 9 clusters
Physical exercise at home (HOME) n = 89 subjects, n = 9 clusters
10 lost to follow-up
6 lost to follow-up
9 clusters with 111 subjects included in analysis 0 excluded in analysis
9 clusters with 89 subjects included in analysis 0 excluded in analysis
Figure 1. Participant recruitment flow chart. Table I. Characteristics of study participants. Values are reported as mean (SD).
N Age (years) Height (cm) Weight (kg) BMI (kg∙m–2) Perceived physical exertion (scale 0–10) Need for recovery (scale 1–5)
HOME
WORK
89 44 (10) 168.0 (7.2) 68.9 (12.2) 24.4 (4.0) 3.49 (1.63)
111 40* (12) 168.4 (6.2) 67.5 (12.1) 23.8 (3.8) 3.73 (1.95)
3.25 (0.70)
3.23 (0.82)
HOME: home-based physical exercise; WORK: Work-based physical exercise. *Difference between groups at baseline, p < 0.05.
Downloaded from sjp.sagepub.com at RMIT UNIVERSITY on July 15, 2015
4 M.D. Jakobsen et al. training instructor, who supervised and instructed the participants in how to perform the exercises, and helped with exercise adjustment when needed. The training program consisted of 10 exercises: kettlebell deadlifts, kettlebell swings, squeeze, lateral raises, golf swings, and woodchoppers using elastic tubing, abdominal crunches, back extensions, and squats using a swissball, and lunges using elastic tubing (Figure 2). For each training session the instructor chose four to six exercises that were performed as circuit training, i.e. with quick transitions from one exercise to the next using no or minimal periods of rest. Progression in training intensity (loads) was ensured by using progressively more resistant elastic bands and heavier kettlebells throughout the 10-week intervention period, as supervised by the instructors. In addition, WORK was offered five group-based motivational coaching sessions (30–45 min with 5–12 participants in each session) during working hours. Home-based physical exercise (HOME) Participants randomized to home-based physical exercise (HOME) (n=89 subjects, n=9 clusters) performed strength training exercises during leisure time at home. At initiation of the study, participants received a bag with (1) training equipment (easy, medium, and hard elastic tubing) and (2) three posters that visually demonstrated the elastic band and body weight exercises that should be performed for the shoulder, abdominal and back muscles, and also contained recommendations for training progression [16]. Ergonomic training and education. During the period of intervention participants in both groups were offered to participate in brief courses (1.5–3 hours each) of ergonomic training and education in patient handling and use of assistive devices. The courses were managed by the hospital’s working environment department. Outcome measures Perceived physical exertion. Participants were asked the following question, based on Borg’s Rate of Perceived Exertion (RPE) scale, at baseline and after the 10-week intervention period: “How would you rate your physical exertion while working with the patients?” Subjects replied on a scale with seven exertion levels taken from the BORG CR10 scale (0–10): f “very, very light” (RPE = 0.5), “very light” (RPE = 1), “light” (RPE = 2), “moderately strenuous” (RPE = 3), “strenuous” (RPE = 5), “very strenuous” (RPE
Figure 2. Exercises used in the physical exercise program at work: (1) deadlifts using kettlebell, (2) kettlebell swings, (3–6) squeeze, lateral raises, golf swings and woodchoppers using elastic tubing, (7–9) abdominal crunches, back extensions and squats using swissball, (10) lunges using elastic tubing.
= 7), and “very, very strenuous” (RPE = 9) [18]. The Borg RPE scale has been validated in many different contexts to measure actual exertion, e.g. perceived exertion during manual handling tasks [12,18]. Need for recovery. Participants were further asked how exhausted they were at the end of the working day. They replied to the following single item question from the Need for Recovery Scale at baseline and after the 10-week intervention period: “By the end of the working day, I feel really worn out” [19]. Subjects replied on a five-point scale of (I) “never”, (II) “rarely”, (III) “once in a while”, (IV) “most of
Downloaded from sjp.sagepub.com at RMIT UNIVERSITY on July 15, 2015
Physical exercise at the workplace reduces perceived physical exertion during healthcare work 5 the time,” and (V) “always”. The Need for Recovery Scale has been validated for multiple job groups [20].
Perceived exeron 3.7
Statistical analysis
3.45
Borg (0-10)
All statistical analyses were performed using the SAS statistical software for Windows (SAS Institute, Cary, NC). The change in physical exertion (0–10 scale) was evaluated using a repeated-measures two-way analysis of variance (ANOVA) with group, time, and group by time as independent variables. Participant nested within department was entered as the random effect to account for clustering. Analyses were adjusted for age and physical exertion at baseline. All statistical analyses were performed in accordance with the intention-to-treat principle, i.e. using the mixed procedure which inherently accounts for missing values. An alpha level of 0.05 was accepted as statistically significant. Outcomes are reported as between-group least mean square differences and 95% confidence intervals at follow-up. During the process of post hoc statistical analysis effect sizes were calculated as Cohen’s d [21] based on the observed within-group changes (within-group changes from baseline to follow-up divided by the pooled standard deviation at baseline) and the standardized mean difference (i.e. between-group differences in the physical exertion scores divided by the pooled standard deviation at baseline). According to Cohen, effect sizes of 0.20 are considered small, 0.50 moderate, and 0.80 large [21]. Based on previous measurements of pain intensity the a priori power analysis revealed that 64 participants in each group were needed to achieve 95% statistical power and SD of 1.5, while a minimal relevant pre-to-post difference of pain intensity of 1 [22] was sufficient to test the null-hypothesis of equality (α=0.05). At an estimated 25% drop-out rate, group sizes were calculated to be at least 80. Because of an estimated inflation factor of 1.2 due to clustering effects, the estimated minimal group size was deemed to be 96. The inflation factor used for the sample size calculations were based on the between- and within-cluster variance from a previous study [23].
3.2
**
2.95
2.7 0-wks
10-wks HOME
WORK
Figure 3. Scores of perceived physical exertion at baseline (0 weeks) and follow-up (10 weeks) in participants allocated to workplace exercise (WORK; full lines) or home-based exercise (HOME; dashed lines). Values are means (SE). ** Greater reduction in RPE with workplace exercise compared to home-based exercise (p < 0.01).
Training adherence differed between the groups (p
SJP0010.1177/1403494815590936M.D. Jakobsen et al.Physical exercise at the workplace reduces perceived physical exertion during healthcare work
Scandinavian Journal of Public Health, 1–8
Original Article
Physical exercise at the workplace reduces perceived physical exertion during healthcare work: cluster randomized controlled trial
Markus DUE Jakobsen1,2, Emil Sundstrup1,2, Mikkel Brandt1,3, Kenneth Jay1,2,4, Per Aagaard2 & Lars L. Andersen1 1National Research Centre for the Working Environment, Copenhagen, Denmark, 2Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, Denmark, 3Physical Activity and Human Performance group, SMI, Department of Health Science and Technology, Aalborg University, Denmark, and 4Electronics and Computer Science, Faculty of Physical and Applied Sciences, University of Southampton, Southampton, UK
Abstract Background:High physical exertion during work is a risk factor for musculoskeletal pain and long-term sickness absence. Physical exertion (RPE) reflects the balance between physical work demands and physical capacity of the individual. Thus, increasing the physical capacity through physical exercise may decrease physical exertion during work. This study investigates the effect of workplace-based versus home-based physical exercise on physical exertion during work (WRPE) among healthcare workers. Methods: 200 female healthcare workers (age: 42.0, body mass index: 24.1, average pain intensity: 3.1 on a scale of 0 to 10, average WRPE: 3.6 on a scale of 0 to 10) from 18 departments at three participating hospitals. Participants were randomly allocated at the cluster level to 10 weeks of: (1) workplace physical exercise (WORK) performed in groups during working hours for 5×10 minutes per week and up to five group-based coaching sessions on motivation for regular physical exercise, or (2) home-based physical exercise (HOME) performed during leisure time for 5×10 minutes per week. Physical exertion was assessed at baseline and at 10-week follow-up. Results: 2.2 (SD: 1.1) and 1.0 (SD: 1.2) training sessions were performed per week in WORK and HOME, respectively. Physical exertion was reduced more in WORK than HOME (p 160, diastolic BP > 100), (2) a medical history of serious cardiovascular diseases (e.g. chest pain during physical exercise, heart failure, myocardial infarction and stroke), (3) a medical history of life-threatening disease, or (4) current pregnancy. Seven workers were excluded due to contraindications detected during the baseline clinical examination: five due to high blood pressure and two due to blood clot incidence within the last 2 years. The overall flow of participant enrolment is depicted in Figure 1.
Screening quesonnaires sent n = 490 subjects Did not reply n = 176 subjects Replied to quesonnaire n = 314 subjects Declined to parcipate n = 39 subjects Interested in parcipang n = 275 subjects Did not meet eligibility criteria n = 22 subjects Invited for clinical examinaon n = 253 subjects
Randomization and blinding We randomly allocated the 18 departments (200 participants), using a computer-generated random numbers table (performed by a statistician), to receive either physical exercise at the workplace or at home. Participants at each department and their management were subsequently informed by e-mail about group allocation. All examiners were blinded to the group allocation at follow-up (i.e. post intervention) testing (December 2013 to January 2014), and participants carefully instructed not to reveal their particular intervention group. Baseline characteristics, physical exertion scores and exhaustion at the end of the workday of the two intervention groups are presented in Table I. Interventions Each cluster of participants was allocated to a 10-week intervention period of either performing physical exercise at the hospital or performing physical exercise at home. Both exercise groups were encouraged to perform physical exercises for 5 × 10 minutes a week. The specific intervention protocols have been described in detail elsewhere [16] and are briefly summarized below. Workplace physical exercise (WORK) Participants randomized to physical exercise at their workplace (WORK) (n=111 subjects, n=9 clusters) performed group-based and supervised high-intensity strength training using elastic bands (TheraBand®) and kettlebells during working hours at the hospital. All training sessions took place in designated rooms located close to the respective departments. All sessions were supervised by an experienced
Did not show up for clinical examinaon n = 46 subjects Baseline examinaon n = 207 subjects Excluded due to contraindicaons n = 7 subjects Cluster randomizaon n = 200 subjects, n = 18 clusters
Physical exercise at the hospital (WORK) n = 111 subjects, n = 9 clusters
Physical exercise at home (HOME) n = 89 subjects, n = 9 clusters
10 lost to follow-up
6 lost to follow-up
9 clusters with 111 subjects included in analysis 0 excluded in analysis
9 clusters with 89 subjects included in analysis 0 excluded in analysis
Figure 1. Participant recruitment flow chart. Table I. Characteristics of study participants. Values are reported as mean (SD).
N Age (years) Height (cm) Weight (kg) BMI (kg∙m–2) Perceived physical exertion (scale 0–10) Need for recovery (scale 1–5)
HOME
WORK
89 44 (10) 168.0 (7.2) 68.9 (12.2) 24.4 (4.0) 3.49 (1.63)
111 40* (12) 168.4 (6.2) 67.5 (12.1) 23.8 (3.8) 3.73 (1.95)
3.25 (0.70)
3.23 (0.82)
HOME: home-based physical exercise; WORK: Work-based physical exercise. *Difference between groups at baseline, p < 0.05.
Downloaded from sjp.sagepub.com at RMIT UNIVERSITY on July 15, 2015
4 M.D. Jakobsen et al. training instructor, who supervised and instructed the participants in how to perform the exercises, and helped with exercise adjustment when needed. The training program consisted of 10 exercises: kettlebell deadlifts, kettlebell swings, squeeze, lateral raises, golf swings, and woodchoppers using elastic tubing, abdominal crunches, back extensions, and squats using a swissball, and lunges using elastic tubing (Figure 2). For each training session the instructor chose four to six exercises that were performed as circuit training, i.e. with quick transitions from one exercise to the next using no or minimal periods of rest. Progression in training intensity (loads) was ensured by using progressively more resistant elastic bands and heavier kettlebells throughout the 10-week intervention period, as supervised by the instructors. In addition, WORK was offered five group-based motivational coaching sessions (30–45 min with 5–12 participants in each session) during working hours. Home-based physical exercise (HOME) Participants randomized to home-based physical exercise (HOME) (n=89 subjects, n=9 clusters) performed strength training exercises during leisure time at home. At initiation of the study, participants received a bag with (1) training equipment (easy, medium, and hard elastic tubing) and (2) three posters that visually demonstrated the elastic band and body weight exercises that should be performed for the shoulder, abdominal and back muscles, and also contained recommendations for training progression [16]. Ergonomic training and education. During the period of intervention participants in both groups were offered to participate in brief courses (1.5–3 hours each) of ergonomic training and education in patient handling and use of assistive devices. The courses were managed by the hospital’s working environment department. Outcome measures Perceived physical exertion. Participants were asked the following question, based on Borg’s Rate of Perceived Exertion (RPE) scale, at baseline and after the 10-week intervention period: “How would you rate your physical exertion while working with the patients?” Subjects replied on a scale with seven exertion levels taken from the BORG CR10 scale (0–10): f “very, very light” (RPE = 0.5), “very light” (RPE = 1), “light” (RPE = 2), “moderately strenuous” (RPE = 3), “strenuous” (RPE = 5), “very strenuous” (RPE
Figure 2. Exercises used in the physical exercise program at work: (1) deadlifts using kettlebell, (2) kettlebell swings, (3–6) squeeze, lateral raises, golf swings and woodchoppers using elastic tubing, (7–9) abdominal crunches, back extensions and squats using swissball, (10) lunges using elastic tubing.
= 7), and “very, very strenuous” (RPE = 9) [18]. The Borg RPE scale has been validated in many different contexts to measure actual exertion, e.g. perceived exertion during manual handling tasks [12,18]. Need for recovery. Participants were further asked how exhausted they were at the end of the working day. They replied to the following single item question from the Need for Recovery Scale at baseline and after the 10-week intervention period: “By the end of the working day, I feel really worn out” [19]. Subjects replied on a five-point scale of (I) “never”, (II) “rarely”, (III) “once in a while”, (IV) “most of
Downloaded from sjp.sagepub.com at RMIT UNIVERSITY on July 15, 2015
Physical exercise at the workplace reduces perceived physical exertion during healthcare work 5 the time,” and (V) “always”. The Need for Recovery Scale has been validated for multiple job groups [20].
Perceived exeron 3.7
Statistical analysis
3.45
Borg (0-10)
All statistical analyses were performed using the SAS statistical software for Windows (SAS Institute, Cary, NC). The change in physical exertion (0–10 scale) was evaluated using a repeated-measures two-way analysis of variance (ANOVA) with group, time, and group by time as independent variables. Participant nested within department was entered as the random effect to account for clustering. Analyses were adjusted for age and physical exertion at baseline. All statistical analyses were performed in accordance with the intention-to-treat principle, i.e. using the mixed procedure which inherently accounts for missing values. An alpha level of 0.05 was accepted as statistically significant. Outcomes are reported as between-group least mean square differences and 95% confidence intervals at follow-up. During the process of post hoc statistical analysis effect sizes were calculated as Cohen’s d [21] based on the observed within-group changes (within-group changes from baseline to follow-up divided by the pooled standard deviation at baseline) and the standardized mean difference (i.e. between-group differences in the physical exertion scores divided by the pooled standard deviation at baseline). According to Cohen, effect sizes of 0.20 are considered small, 0.50 moderate, and 0.80 large [21]. Based on previous measurements of pain intensity the a priori power analysis revealed that 64 participants in each group were needed to achieve 95% statistical power and SD of 1.5, while a minimal relevant pre-to-post difference of pain intensity of 1 [22] was sufficient to test the null-hypothesis of equality (α=0.05). At an estimated 25% drop-out rate, group sizes were calculated to be at least 80. Because of an estimated inflation factor of 1.2 due to clustering effects, the estimated minimal group size was deemed to be 96. The inflation factor used for the sample size calculations were based on the between- and within-cluster variance from a previous study [23].
3.2
**
2.95
2.7 0-wks
10-wks HOME
WORK
Figure 3. Scores of perceived physical exertion at baseline (0 weeks) and follow-up (10 weeks) in participants allocated to workplace exercise (WORK; full lines) or home-based exercise (HOME; dashed lines). Values are means (SE). ** Greater reduction in RPE with workplace exercise compared to home-based exercise (p < 0.01).
Training adherence differed between the groups (p
