Jumper's Knee Mechanical Consequences in Professional Basketball Players: the "Camel's Back Curve"

Purpose: Jumper's knee is characterized by an anterior knee pain during tendon palpation and can be classified in overuse pathologies, secondary to repetitive jumps. The prevalence is high in professional basketball players. It is responsible for an alteration of the motor control inducing a strength deficit of the quadriceps. We aimed to describe an isokinetic curve anomaly, a double-humped curve called "Camel's Back curve", consequence of a jumper's knee history.

Methods: 170 Professional basketball players were enrolled (24.8 ± 4.6 years; 91.8 ± 12.0 kg, 194 ± 9.0 cm). All players performed isokinetic tests of the knee extensors on a concentric mode at the angular speed of 60°/s and 180°/s.

Results: 43 players had a jumper's knee history and 35 (81%) had a "Camel's Back curve" at 60°/s. The sensitivity and the specificity of this curve were 81.3% and 100%, respectively. The minimum torque of strength was decreased from 12 to 18% compared to the 2 maximal peaks. Yet, the strength measured every 5° of ROM was significantly different between the players with "Camel's Back curve" and those with normal curve.

Conclusions: "Camel's Back curve" had never been described in that context. It may be secondary to a protective inhibitory mechanism which could alter jumping. The presence of a "Camel's Back curve" would enable clinicians to adapt physical preparation, knee rehabilitation, and trainings to improve players performances.