Jumper’s knee mechanical consequences in professional basketball players: the “Camel’s Back curve”
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.
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.
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.
“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.
KeywordsPatellar tendon Jump Quadriceps Basketball Isokinetic
Analysis of variance
Limb symmetry index
Physical medicine and rehabilitation
Range of motion
All authors conceived and designed the research protocol, read and approved the final manuscript. MD conducted experiments and analyzed the data. MD and AFC wrote the manuscript.
Compliance with ethical standards
Applicable institutional and governmental regulations concerning ethics were followed during this research. The data report form was declared to the French data protection authority (Commission Nationale de l’Informatique et des Libertés) and to the Research Department of the University Hospital under the registration number RC18_0025. Since data were collected retrospectively and that patients’ management had not been modified, according to the French law, this study did not need to be approved by a research ethics committee (articles L.1121-1 paragraph 1 and R1121-2, Public Health code).
Conflict of interest
The authors have no conflict of interest to declare.
- Ayalon M, Barak Y, Rubinstein M (2002) Qualitative analysis of the isokinetic moment curve of the knee extensors. Isokinet Exerc Sci 10:145–151Google Scholar
- Balčiūnas M, Stonkus S, Abrantes C, Sampaio J (2006) Long term effects of different training modalities on power, speed, skill and anaerobic capacity in young male basketball players. J Sports Sci Med 5:163–170Google Scholar
- Blazina ME, Kerlan RK, Jobe FW et al (1973) Jumper’s knee. Orthop Clin North Am 4:665–678Google Scholar
- Clarsen B, Myklebust G, Bahr R (2013) Development and validation of a new method for the registration of overuse injuries in sports injury epidemiology: the Oslo Sports Trauma Research Centre (OSTRC) overuse injury questionnaire. Br J Sports Med 47:495–502. https://doi.org/10.1136/bjsports-2012-091524 CrossRefGoogle Scholar
- Hadzić V, Erculj F, Bracic M, Dervisević E (2013) Bilateral concentric and eccentric isokinetic strength evaluation of quadriceps and hamstrings in basketball players. Coll Antropol 37:859–865Google Scholar
- Zakas A, Mandroukas K, Vamvakoudis E et al (1995) Peak torque of quadriceps and hamstring muscles in basketball and soccer players of different divisions. J Sports Med Phys Fitness 35:199–205Google Scholar