LIFETIME EXERCISE AND DISK DEGENERATION - AN MRI STUDY OF MONOZYGOTICTWINS

Participation in some competitive sports has been shown to increase di sk degeneration; however, the long-term effects of recreational physic al activities are unclear. We investigated the effects of endurance ex ercise and power sports on disk degeneration in monozygotic male twins with contrasting lifetime exercise histories. The effects of enduranc e exercise were studied in 22 discordant twin pairs (mean lifetime fre quencies of 3.9 vs 1.1 times/wk), and the effects of power sports were investigated in 12 discordant pairs (2,300 vs 200 h of weightlifting) . The age range of the twins was from 35 to 69 yr. No differences in M RI findings between co-twins discordant for endurance exercise were fo und at any of the spinal regions. Subjects with more power sport invol vement had greater disk degeneration in the T6-T12 region (P < 0.03), but similar findings were not present in the lumbar spine. Controlling for recalled back injuries, occupational loading, smoking, and drivin g did not significantly affect the results. No signs of beneficial or harmful effects of lifetime endurance exercise on disk degeneration we re seen. Increased power sport participation was associated with sligh tly greater disk degeneration in the lower thoracic spine, but not in the lumbar spine.