Serum Cartilage Oligomeric Matrix Protein: is There a Repeated Bout Effect?

The primary aim of the present study was to investigate if there is a repeated bout effect for cartilage tissue, evident in the marker serum cartilage oligomeric matrix protein (sCOMP). Ten healthy male subjects (26.4±3.14 years) performed two high impact interventions (100 drop jumps with a 30 second interval) carried out at a 3 week interval. After each intervention, sCOMP and muscle soreness were assessed on 8 and 6 occasions respectively. Muscle soreness was determined via a visual analog scale with a maximum pain score of 10. sComp levels did not show a blunted response after the second bout (Bout 1: 12.2±3.3 U/L(-1); Bout 2: 13.1±4.0 U/L(-1); P>0.05). Remarkably, sCOMP increased from baseline levels by 16% after bout 1 and 15% after bout 2. Muscle soreness was blunted following the second intervention (Bout 1: 5.0±1.8; Bout 2: 1.6±0.8). Unlike the known repeated bout effect for muscle damage markers, sCOMP levels do not show a blunted response after two similar loading interventions. This information on biomarker behavior is essential to clinicians attempting to use this marker as an indicator of cartilage damage associated with the development or progression of osteoarthritis.