Background Hiking activity during sailing involves the hips, trunk, head, and upper extremities held in sustained, unsupported positions over the side of a boat to stabilize it at an optimal angle to the water, preventing velocity loss and overturn. Hiking requires high forces generated by lower extremities and trunk, potentially producing high lumbar spine compression and shear loads linked to acute Low Back Pain.
Objective This study examined if competitive sailors performing hiking were at increased risk of developing low back pain (LBP) compared to non-hikers over the course of an Olympic class regatta.
Design Prospective Cohort.
Setting World Cup Regatta.
Patients (or Participants) 172 Olympic class sailors completed a questionnaire concerning sailing activities, previous history of, and new LBP following a 6-day regatta. 152 subjects without LBP at the beginning of the regatta were classified as exposed (hikers) and unexposed (non-hikers) and new LBP cases were recorded for both groups.
Interventions (or Assessment of Risk Factors) Relative risk ratios (RR) and CI95% were calculated compared risk of new LBP in hikers and non-hikers. A priori hypothesis tested: hiking sailors are at increased risk for incident LBP versus non-hikers.
Main Outcome Measurements Self-report LBP limiting sailing.
Results Twenty-two subjects reported new LBP, 18 from hiking exposure group. Exposed (n=84) and unexposed (n=68) were no different in demographic/anthropometric variables across exposure and disease groups. Boat/equipment unloading time differences persisted across groups (P=0.0016, P=0.0022 respectively). Hikers' raw RR was 3.64 (CI 95% 1.29,10.26) times greater than non-hikers' for developing new LBP. Hikers' risk controlled for unloading time levels yielded an adjusted RR of 2.73 (CI 95% 1.05, 7.08). Hikers exposed to high unloading levels (>2 hours) RR was 8.3 (CI 95% 1.05, 65.76) versus non-hikers.
Conclusions Hiking and unloading forces may be risk factors for LBP prior to and during Olympic class regattas. Further study recommended.