Background: Chronic low back pain (CLBP) is a serious problem in Military Police Officers (MPO), which accounts for up to 45% of the sick leave rates. It has been assumed that the strength and the endurance of trunk flexor and extensor muscles are CLPB key factors, but it is not known whether these attributes are related to pain intensity. It was aimed to determine whether the strength and endurance of trunk flexor and extensor muscles differ in MPO with no pain (CON; n = 24), moderate (MOD; n = 42), and severe (SEV; n = 37) nonspecific chronic low back pain (CLBP). Methods: The peak torque and endurance test of trunk flexor (PTF.BM−1) and extensor (PTE.BM−1) muscles were compared. A multiple regression analysis was used to identify pain intensity predictors in all groups (PAIN) and according to pain intensity (MOD and SEV). Results: The PTF.BM−1 was negatively related to pain and was a significant predictor, irrespective of pain intensity (PAIN). Conclusion: When pain intensity was considered the PTF.BM−1 and PTE.BM−1 explained the pain in the MOD, while the PTE.BM−1 and service time explained pain intensity in the SEV. Endurance of the flexor and extensor muscles was not related to pain intensity. These results indicated that training protocols must emphasize specific strengthening routines.

Objective Military personnel has a large prevalence of back pain, especially those involved in patrolling routines, as they wear heavy protective equipment. Patrolling includes long periods of sustaining the protective equipment in a sitting or in a motor vehicle (motorcycle or car). Thus, understanding spinal loading of military police officers after patrolling by car (CAR; n = 14), motorcycle (MOT; n = 14), and administrative (ADM; n = 14) routines is relevant to establish preventive strategies. Methods The torque of the trunk and working and anthropometric characteristics were assessed to explain spinal loading using stature variation measures. Precise stature measures were performed before and after a 6 h journey (LOSS) and 20 min after a resting posture (RECOV). The trunk extensor (PTE BM −1 ) and flexor (PTF BM −1 ) muscles' isometric peak torque were measured before the working journey. Results The LOSS was similar between CAR and MOT (4.8 and 5.8 mm, respectively) after 6 h of patrolling. The ADM presented the lowest LOSS (2.8 mm; P < .05). No changes in RECOV between groups were observed ( P > .05). Vibration may explain the greater spinal loading involved in patrolling in comparison to the ADM. A GLM analysis revealed that BMI was the only explanatory factor for stature loss. No independent variables explained RECOV. The ability of the trunk muscles to produce force did not influence LOSS or RECOV. Conclusions Military police officers involved in patrolling may require greater post‐work periods and strategies designed to reduce the weight of the protective apparatus to dissipate spinal loading. The external load used in patrolling is a relevant spinal loading factor.