Abstract

We investigated whether ingesting a supplement containing GOPO^® has an effect on the passive forces during flexion/extension of the knee and self-reported pain in active non-arthritic participants. Thirty physically active male participants between the ages of 35–60 were randomly allocated to either placebo or active supplement groups. Measurements of body composition, hydration, physical activity, subjective aches/pains and passive lower leg forces were recorded at baseline and 2, 6 and 12 weeks, using a Biodex System 3 isokinetic dynamometer at 5, 60, 90, and 120 degrees per second. Both groups reported a drop in mean perceived aches and pains between baseline and 12 weeks, the decrease was greater for the active group 14% compared to 8% in the placebo group. At the slower speed (5° per second) there was a mean decrease in passive total work during knee flexion and extension of 8.4% and 13.7% respectively in the active group after 12 weeks when compared to baseline. The placebo group showed no such reduction (0.5% decrease in flexion and 0.7% decrease in extension). The decrease in passive torque observed at the slower speeds following 12 weeks of supplement ingestion showed promising trends that warrant further investigation. A general reduction in passive torque might indicate a change in the compliancy of the series and parallel elastic components or a change in cartilage compliance which might in the long term reduce joint degeneration.