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OBJECTIVES: Despite the fact that team manual handling is common in different working environments, the previous studies in this regard, particularly those with a physiological approach are quite limited. The present study is an attempt to model the heart rate (HR) of individual and team manual handling with one hand. METHODS: Twenty-five young men (aged 21.24±1.42 year) volunteered for this study. The experiments included individual and two-person handling of the load with three different weights with and without height difference. The participants' HR was registered at the end of the route by a chest-strap pulse monitor and a polar watch according to the manufacturer's recommendation. A multivariate Generalized Additive Mixed Model (MGAMM) was used for modeling heart rate based on explanatory variables of workload, carry method, HRrest, body weight, height, knee height, shoulder height, elbow height, and hand height. The significance level of the tests was considered as <0.05. RESULTS: Based on the MGAMM, the average HR (bpm) of participants increased as the workload increased (P<0.001). Handling the load with a taller person increased the HR compared to shorter partner (P<0.001). Moreover, the nonlinear associations of the resting HR (P<0.001), body weight (P<0.001), height (P<0.001), and the height of elbow, hand and knee (P<0.001) were statistically significant. The adjusted R2 of the model was 0.89 indicating that about 90 percent of the variations observed in HR could be explained by the variables in the model. This was greater than the model considering only linear effects (R2 =0.60). CONCLUSION: The model obtained in this study can predict the heart rate of individual and team one-handed handling with high validity. The MGAMM can be used in modeling heart rate in manual handling.
Assuntos
Carga de Trabalho , Masculino , Humanos , Frequência Cardíaca , Peso CorporalRESUMO
Objectives. Team manual handling, a process still common in many jobs, can affect the safety and health of employees. A systematic review of the literature was conducted to identify the research gaps in this area for future studies. Methods. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was followed. Related papers were searched on PubMed, Web of Science, ProQuest and Scopus electronic databases until September 2020. Results. A total of 300 papers were identified, of which 28 were selected for final review based on the respective criteria. The findings of these studies were classified and evaluated based on biomechanical, physiological and psychophysical approaches. No study was found for the epidemiological approach. Only three papers mentioned the body physiological responses in team manual handling. The focus of the related studies found in this field was team lifting. No study was found on team pulling and pushing. Most studies were performed in a laboratory setting using young students who had no experience of team manual handling. Conclusion. The results of this study emphasize the need for further research, especially using the epidemiological and physiological approaches in different tasks of team manual handling in real work environments using experienced workers.
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BACKGROUND: Ghrelin, a 28 amino acid peptide, is effective in control of appetite and body weight. Acylated ghrelin peptide is the active form of this peptide which plays a major role in the body's energy balance. OBJECTIVES: This study aimed to investigate the possible effect (s) of intensive resistance exercise on acylated ghrelin, growth hormone, glucose, insulin, and cortisol plasma levels. PATIENTS AND METHODS: Forty male students with the mean age of 19.22 ± 0.26 years and BMI 21.02 ± 0.33 (kg/m(2)) were randomly divided into experimental and control groups. Experimental group performed a single session of circuit resistance exercise with 80% 1RM in both fasting and high carbohydrate meal. Blood samples were collected before and immediately after exercise to measure the concentrations of mentioned variables. RESULTS: Two-way ANOVA showed that acylated ghrelin and fasting plasma glucose levels after exercise in both high-carbohydrate and fasting groups were significantly increased compared to the control group (P < 0.05), but the levels of insulin, cortisol, and growth hormones did not have any significant change. CONCLUSIONS: Totally, it seems that the increased plasma acylated ghrelin during exercise is due to the decrease of muscle and liver energy stores which provides conditions for increased energy intake and positive energy balance.
