Differences in tendon properties in elite badminton players with or without patellar tendinopathy

The aim of this study was to examine the structural and mechanical properties of the patellar tendon in elite male badminton players with and without patellar tendinopathy. Seven players with unilateral patellar tendinopathy (PT group) on the lead extremity (used for forward lunge) and nine players with no current or previous patellar tendinopathy (CT group) were included. Magnetic resonance imaging was used to assess distal patellar tendon dimensions. Patellar tendon mechanical properties were assessed using simultaneous tendon force and deformation measurements. Distal tendon cross-sectional area (CSA) normalized for body weight (mm2/kg2/3) was lower in the PT group compared with the CT group on both the non-lead extremity (6.1 +/- 0.3 vs 7.4 +/- 0.2, P<0.05) and the lead extremity (6.5 +/- 0.6 vs 8.4 +/- 0.3, P<0.05). Distal tendon stress was higher in the PT group compared with the CT group for both the non-lead extremity (31 +/- 1 vs 27 +/- 1MPa, P<0.05) and the lead extremity (32 +/- 3 vs 21 +/- 3MPa, P<0.01). Conclusively, the PT group had smaller distal patellar tendon CSA on both the injured (lead extremity) and the uninjured side (non-lead extremity) compared with the CT group. Subsequently, the smaller CSA yielded a greater distal patellar tendon stress in the PT group. Therefore, a small tendon CSA may predispose to the development of tendinopathy.