Strength Sensibility of Lumbar Extensor and Flexor Muscles during Static and Dynamic Exercise

Thorwesten L, Poller D, Fromme A, Mooren FCh, Völker K

Zusammenfassung

Recluced kinesthetic perceptions can impair the sensorimotor functions of the lower back and may result in an increased risk of injury. The aim of this study was the evaluation of dynamic and staticstrength sensibility of the lower back muscles. After executing a trial run one week before testing, 29 volunteers (11 elite athletes, 24.8 years; 18 recreational athletes, 25.1 years) performed a maximum isokinetic strength test (30°/s) ofthe thoraco-lumbar muscles, as well as a maximum isometric strength test at 35° flexion. Subjects performed three trials for each test. The maximum static and dynamic strength values were reproduced with a70% [A], as weil as 50% [B], gradation of peak torque. Focusing on dynamic strength gradation, the lower back extensor muscles ( + 5.9% [A], + 4.0% [B]) showed more accurate values than the flexor muscles (+ 14.3% [A], + 17.7% [B]). The elite athletes revealed more accurate values in strength gradation. Regarding staticstrength gradation, the lower back flexion values (-14% [A]; -9.4%(B]) were more precise than the extension values (- 30.2% [A],-23.2% [BI). These findings point to an incremented sensory input during dynamic extension movements of the lower back and can be explained by more accurate proprioceptive adjustments during dynamic exercise compared to static exerise.