Comportamento mecânico da coluna vertebral e a dor lombar durante a jornada de trabalho de policiais militares motociclistas

Abstract

Chronic low back pain (CLBP) affects most of the population, generating medical, social, labor and premature disability. One of the categories of professionals who suffer from it are Military Police Officers. Long working hours in the same posture, motorcycles‟ vibration, overload of equipment and physical and psychological tasks related to work, all contribute to CLBP. The aim of the research was to investigate spinal overload, low back pain, torque of flexor and extensor musclesof the trunk and the recovery of the stature of police motorcyclists during the working day. A cross- sectional, descriptive, exploratory and preexperimental study was carried out. Sample consisted of 20 officers from Paraná, motorcyclists (ROCAM), aged 35.15±4.68 years; working as a police officer 9.25±3.45 years; service time at ROCAM of 4.6±1.85 years; body mass 83.51±9.78kg; equipped body mass 96.83±9.69kg; height 175.5±6.06cm; BMI 27.05±3.26. To determine the biomechanical behavior of the spine, the following evaluations were carried out: a) height variation assessment using stadiometry every two hours during work day and, after 30′ intervention in Fowler position; b) monitoring every two hours to assess the intensity of LBP using the visual pain scale; c) at the beginning and at the end of the working day, the strength of the trunk flexor and extensor muscles was measured by the dynamometer.The data were submitted to a standard descriptive analysis (mean and standard deviation). To verify height variation and the intensity of LBP during workday in PRE conditions; 2; 4 and 6 hours and after recovery the ANOVAoneway to repeated measurements was applied. The t test was used to observe the differences in the muscle torque of the trunk (PRE and POS workday). Simple and multiple linear regression analyzes (Stepwise method) were performed with the study variables. It was using the IBM SPSS Statistics 25.0 software and the variables tested with significance level of p <0.05. Significant variations (p<0.01) in height were found in relation to the beginning of the task and the moments of 2, 4 and 6 hours (with losses of 4.82±1.90mm, 5.53±1.65mm and 6.75±1.72mm, respectively) and after intervention in the recovery position (p <0.01). The recovery period caused a significant change in height in relation to the 6 and 4 hours (p <0.01), recovering 63% of the lost height (4.27±1.72mm). Pain increased significantly after 2, 4 and 6 hours of work when compared to the beginning of the day (p <0.05). Fowler’s position was sufficient to cause a significant reduction in pain in relation to 6 hours (p <0.01). The weight of the uniformed policeman showed an association with the spine shrinkage (p = 0.0444, r² = 0.206) and after 2 hours of work (p = 0.0345 and r² = 0.225). Individuals with greater torque in the trunk extensor muscles had greater height recovery (p = 0.0392, r² = 0.215). Extensor muscles had significant redution of strength at the end of shift (p=0,02). There was negative association between percentage of recovery and LBP (p = 0.003, r² = 0.529). Percentage of recovery was also associated with torque of extensors by body weight (p =0.023) and LPB (p <0.01) reported at the end of the workday. Findings may contribute to prevent and improve the police‟s health, in addition to subsidizing the purchase of lighter and ergonomic equipment, and motorcycles compatible with job.