Research Study Abstract

A longitudinal observational study of back pain incidence, risk factors and occupational physical activity in Swedish marine trainees

  • Published on May 14, 2019

To evaluate the occurrence of low back pain (LBP) and LBP that limits work ability, to identify their potential early risks and to quantify occupational physical activity in Swedish Armed Forces (SwAF) marines during their basic 4 month marine training course.

Prospective observational cohort study with weekly follow-ups.

Fifty-three SwAF marines entering the training course.

Incident of LBP and its related effect on work-ability and associated early risks. Occupational physical activity, as monitored using accelerometers and self-reports.

During the training course, 68% of the marines experienced at least one episode of LBP. This yielded a LBP and LBP limiting work ability incidence rate of 13.5 (95% CI 10.4 to 17.8) and 6.3 (95% CI 4.2 to 10.0) episodes per 1000 person-days, respectively. Previous back pain and shorter body height (≤1.80 m) emerged as independent risks for LBP (HR 2.5, 95% CI 1.4 to 4.3; HR 2.0, 95% CI 1.2 to 3.3, respectively), as well as for LBP that limited work ability (HR 3.6, 95% CI 1.4 to 8.9; HR 4.5, 95% CI 2.0 to 10.0, respectively). Furthermore, managing fewer than four pull-ups emerged as a risk for LBP (HR 1.9, 95% CI 1.2 to 3.0), while physical training of fewer than three sessions per week emerged as a risk for LBP that limited work ability (HR 3.0, 95% CI 1.2 to 7.4). More than 80% of the work time measured was spent performing low levels of ambulation, however, combat equipment (≥17.5 kg) was carried for more than half of the work time.

Incidents of LBP are common in SwAF marines’ early careers. The link between LBP and previous pain as well as low levels of exercise highlights the need for preventive actions early on in a marine’s career. The role of body height on LBP needs further investigation, including its relationship with body-worn equipment, before it can effectively contribute to LBP prevention.


  • Andreas Monnier 1,2,3
  • Helena Larsson 1,4
  • Håkan Nero 5
  • Mats Djupsjöbacka 6
  • Björn O Äng 1,2,7


  • 1

    Division of Physiotherapy, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Huddinge, Sweden

  • 2

    School of Education, Health and Social Studies, Dalarna University, Falun, Sweden

  • 3

    Swedish Armed Forces, Military Academy Karlberg, Stockholm, Sweden

  • 4

    Swedish Armed Forces, Headquarters, Medical Services, Stockholm, Sweden

  • 5

    Department of Orthopedics, Faculty of Medicine, Lund University, Lund, Sweden

  • 6

    Centre for Musculoskeletal Research, Department of Occupational Health Science and Psychology, University of Gävle, Gävle, Sweden

  • 7

    Center for Clinical Research, Uppsala University, Falun, Sweden


BMJ Open

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