Fatigue Induced Effects after Concentric versus Eccentric Exercises on Sense of Force and Senses of Position among Young Normal Adults- A Controlled Single-Blinded Study

Although knee joint proprioception could be affected by muscle contractions, knowledge on muscle fatigue during sports and work activities is limited. This study was aimed to identify the effect of the quadriceps muscle fatigue during concentric and eccentric contractions on knee joint proprioception. Twenty healthy women with mean age of 20.45 ± 1.36 years old performed concentric contractions at first set. One week later, eccentric training was carried out during fatigue protocol. Force Sense, position sense, and knee stability were measured before and after both concentric/eccentric contractions by feedback and non-feedback procedures utilizing Biodex Isokinetic Dynamometer, double-armed goniometer, and centimeter, respectively. There was a significant increase in force sense error and position sense error following eccentric contractions (p = 0.025, p = 0.038). However, concentric contractions only affected position sense (p = 0.028). Position sense improved after concentric contractions, while it was deteriorated following concentric contractions (p = 0.002). There was no evidence of a difference between protocols regarding knee stability. Eccentric contractions addresses lessen in the knee joint proprioception with regard to the sense of force and sense of position. Therefore, eccentric contractions deserve a lot more attention by the athletes because it can be a secret weapon for creating healthier joints.