Effectiveness of a progressive resistance exercise program for industrial workers during breaks on perceived fatigue control: a cluster randomized controlled trial

Abstract

Background: There is strong evidence that physical exercise in the workplace is effective for reducing workers' musculoskeletal complaints. Studies with industrial workers and studies on progressive resistance exercises during breaks are scarce. Our aim was to evaluate the effects of a resistance exercise program on perceived fatigue control among industrial workers. Methods: 204 employees from the dairy industry were allocated to two groups, the intervention group (IG) (n = 98) and the control group (CG) (n = 106). The primary outcome measures were perceived fatigue control and maximum muscle strength, measured through the Need for Recovery Scale and one-repetition maximum contraction (1-RM), respectively. Secondary outcome measures were musculoskeletal complaints, physical activity level, perceived risk factors, physical fitness (BMI, vital signs, and body fat percentage), and workers´productivity. All outcomes were assessed at baseline and then again after 4 months. The IG performed resistance exercises using progressively greater loads while the CG performed general exercise using elastic bands. The exercise protocols were performed three times per week for 20 min. An intention-to-treat analysis was performed using the mixed linear model. Results were considered significant when p < 0.05. Results: The IG did not show to be superior to the CG, although both groups improved perceived fatigue control and muscle strength after the resistance physical exercise program in the worplace. There was also no significant difference between the groups for musculoskeletal complaints and other secondary variables analyzed. However, both groups showed significant improvements between baseline and after 4 months of intervention for all evaluated outcomes (p < 0.05).

Reduction of Fatigue and Musculoskeletal Complaints in Garment Sewing Operator through a Combination of Stretching Brain Gym® and Touch for Health

“…Most other studies were carried out over a longer duration [28][29][30]39]; this study showed a decrease in complaints of general musculoskeletal fatigue over the four-week intervention. Previous research, conducted by Lee et al [50], showed a significant decrease in musculoskeletal symptoms in the neck and shoulders after self-stretching exercise for 4 weeks.…”

“…Most studies were interested in strengthening or resistance exercises, including the study of Santos et al [28] and Andersen et al [33,34,37]; they emphasized that strengthening exercises and specific resistance training of the upper extremity can relieve musculoskeletal pain symptoms in office workers. However, this study looked at the effect of combination stretching and BG + TfH movements that can reduce musculoskeletal complaints without using assistive devices, the movements are not a high risk if you experience the wrong movements, the movements are easy and light.…”

“…In a previous study, it was reported that physical exercise can control the risk factors of fatigue [28,29] and MSDs [30][31][32][33][34][35][36][37][38][39][40]. The types of physical exercise used were physical exercise [30], stretching [31,32], resistance training [28,33], strength training [34], and a combination of stretching and games [30]. In addition, a combination of stretching, resistance, and strength training provides the best results [33,41].…”

“…In addition, a combination of stretching, resistance, and strength training provides the best results [33,41]. Physical exercise has various durations and the frequency of intervention times varies: resistance exercises once a day for 20 min, three times a week for 4 months [28]; 1-h low-intensity running sessions three times a week for a period of six consecutive weeks [29]; 36 different stretches once every 6 min, with stretches lasting 10 to 15 s for 15-17 workdays [31]; a worksite-based physical activities program once a day, lasting 10 min, for 12 months [35]; 10 min daily exercise session for 2 months [36]; physical exercise for 20 min, three times a week for 12 months [37]; resistance training lasting 2 and 12 min, five times a week for 10 weeks [33]; three strength training interventions with different frequencies and durations (1 h once a week, 20 min three times a week, and 7 min nine times a week) for 2 weeks [34]; stretching two times/week for 5-15 min, lasting 6 weeks [38]; exercise training for 10-15 min, three times a week for 11 weeks [39]; exercise two times a week for 3 months [30]; and stretching exercises lasting 10-15 min, two times a day for 4 weeks [32].…”

Maximin design of cluster randomized trials with heterogeneous costs and variances

“…Further, a treatment which affects the mean of an outcome variable can also be expected to affect its variance, making the assumption of homogeneity of variance realistic only under the null hypothesis. Published evidence on this assumption is scarce as homogeneity is routinely assumed in data analysis and rarely tested and reported explicitly, but there is some evidence for heterogeneity in CRTs (for some examples, see Roberts & Roberts, 2005; ; Cheyne et al., 2008; Adachi et al., 2013; Santos et al., 2020), and even more so in clinical psychology (Grissom, 2000). Finally, with respect to costs, the study costs for sampling, treating, and measuring clusters and persons in one treatment arm may be different from those in the other arm.…”