Targeted population of Lithuanian National Defence Volunteer Forces personnel

Participants were asked whether they had experienced low back pain during the past 12 months (yes/no). Participants who responded "yes" were classified into the low back pain group.

LBP intensity was assessed using the Visual Analogue Scale (VAS, 0-10) , where 0 - no pain, and 10 - worst imaginable pain.

Participants were asked to indicate LBP duration. LBP pain duration was classified as acute (<3 months) or chronic (≥3 months)

Muscle strength was assessed using the Biodex System 4 isokinetic dynamometer. Participants were instructed to avoid vigorous physical activity 24 hours before testing and refrain from eating for at least 2 hours prior to assessment. A 10-minute warm-up on a cycle ergometer (50-60 W) and light dynamic exercises were performed before testing. Participants were seated with the backrest at 85° and hip flexion at 90°. The dynamometer axis was aligned with the lateral femoral epicondyle, and the lower leg was secured 2-3 cm above the ankle. The range of motion was set from 70° knee flexion to full extension. The trunk and tested limb were stabilized using straps.

Testing included 5 repetitions at 60°/s and 10 repetitions at 120°/s, with a 30-second rest interval between sets. Prior to testing, participants performed 3-5 familiarization repetitions.

Peak torque normalized to body weight (Nm/kg) was recorded.

Was measured in Nm

Participants were asked whether they had lumbar or lower limb injuries during the past 12 months that could influence the results (yes / no).