Abstract des Autors

Many backbone pathologies, and above all lower back and sacral ones, are strictly affected by a biomechanical change due to an unbalanced relationship between backbone flexors and extensors. This can cause acute joint injuries during violent muscle strain or cyclical repetitions of functional overloads. The isokinetic mode plays an important role either in functional evaluation of various muscle groups, or in the development of rehabilitation programmes, or for muscle performance improvement. The purpose of this study is to evaluate trunk flexors and extensors of young athletes from an isokinetic point of view in order to find out some references values to be used either in athletes' functional evaluation, or to predict premature biomechanical changes which can eventually develop pathologies, and also as the objective of muscle strengthening or rehabilitation programmes. In this study, the subjects tested were 25 male and 25 female ISEF students aged between 19 and 25 years. All the subjects performed a flexion-extension. The countergravitational calibration was performed at 750 flexion. Angular velocities were of 30, 60, 120, 180 deg/sec. The tests were performed from a standing and from a sitting position. Data shows that extensors are stronger than flexors, and male subjects are stronger than female ones also when comparing strength to weight. Peak torques compared to subject weight were higher from a standing position than those obtained from a sitting position due to complementary muscles. The tests performed from a sitting position allow to reduce the action of complementary muscles and therefore to evaluate only the muscles acting on the backbone as well as to protect lower back. Finally we believe angular velocity for muscle rehabilitation or strengthening should be carefully evaluated in order not to overload intensity and duration of exercise without any consequent proportional effect, and in order not to submit the subject to strain and to a high load in a movement unlikely to be performed in usual daily activity. Verf.-Referat