Effect of Local Fatigue in Quadriceps and Hamstring Muscles on Knee Joint Pro- prioception in Healthy Women

* Corresponding Author: Mehdi Khaleghi Tazeji, PhD. Address: Department of Biomechanics and Sport Injuries, Faculty of Physical Education and Sports Sciences, Kharazmi University, Tehran, Iran. Tel: +98 (935) 5348850 E-Mail: mehdikhaleghi60@yahoo.com 1. Department of Physical Education & Sport Sciences, Faculty of Literature, Humanities and Social Sciences, Science and Research Branch of the Islamic Azad University, Tehran, Iran. 2. Department of Biomechanics and Sport Injuries, Faculty of Physical Education and Sports Sciences, Kharazmi University, Tehran, Iran. Mahya Kamrani1 , *Mehdi Khaleghi Tazeji2


Introduction
ith increased activity and participation in sports, the injury potential has enhanced. Thousands of injuries are reported annually, indicating that fatigue impairs neuromuscular control. In turn, it delays neuromuscular activation, increases shear W and torque forces, and endangers joint stability [1]. Fatigue alters muscle tissues.
Moreover, during progressive periods, the body might be unable to recover from training sessions entirely; this matter results in reduced performance [2]. Studies have reported that fatigue decreases knee joint proprioception and the ability to produce knee joint angles. Proprioception is the sense of recognizing different body part locations in space at any given time [3]. Precise and healthy proprioception is essential for optimal joint function in various daily living, occupational, and sports activities. Previous studies have determined ankle, knee, and leg as the most common sites of sports injuries [1,4]. Among the skeletal muscles, the quadriceps are involved in almost all body activities (e.g. running, walking, hitting), and in reducing the effect of ground reaction forces while walking; therefore, the repeated contraction of this muscle in different activities leads to its fatigue [5,6]. Muscle fatigue increases postural oscillation amplitude, decreases balance maintenance ability, and disturbs proprioception. Postural investigations have reported that decreased proprioception disturbs parameters, such as reaction time, postural control, and balance [7,8]. Fatigue is essential in exercise; consequently, it decreases the ability to maintain balance and proprioception in the athletes' knee joints [14,18]. Thus, this study aimed to evaluate the effect of localized fatigue in quadriceps and hamstring muscles on the knee joint proprioception among healthy women.

Methods
This was a quasi-experimental study with a Pre-test-Posttest design. It was conducted on 20 healthy women aged 25-32 years in the Hese Bartar Fitness Club in Tehran City, Iran (Mean±SD age: 27.86±3.75 y; height: 164.43±4.57 cm; weight: 62.18±3.73 kg). The samples voluntarily participated in this study. The knee joint proprioception was measured by a Biodex Multi-joint System 4 Isokinetic Dynamometer by active and passive joint angle reproduction before and after fatigue in quadriceps muscles as well as before and after fatigue in the hamstring muscle. After data collection, the normality of data distribution was assessed using the Kolmogorov-Smirnov test. Furthermore, the Independent Samples t-test was used for statistical analysis. Table 1 presents the Pre-test-Post-test Mean±SD error of angle reproduction and the knee joint proprioception as well as the Independent Samples t-test results. Based on the obtained results, the fatigue of quadriceps and hamstring muscles significantly affected knee joint proprioception. Moreover, fatigue did not affect the knee joint angle of 45°. Fatigue seems to impact the knee joint proprioception more in the knee joint flexion and extension angles' ranges of motion. Besides, the odds of injury are higher in the flexionextension angles of the range of motion.

Discussion
The achieved results were consistent with those of the studies using the isokinetic, isometric, repetitive, and functional fatigue protocols for fatiguing hamstring and quadriceps muscles [12,14,[24][25][26]. Gear et al. investigated the role of different fatigue levels on knee joint proprioception [27]. Similar to our study, they used a Biodex isokinetic dynamometer to create local fatigue in the hamstring muscle group. The subjects performed knee extension and flexion until the peak torque of hamstring was reduced to 10%, 30%, or 50% for three consecutive repetitions.

Conclusion
The local fatigue of the quadriceps and hamstring muscles reduced knee proprioception in healthy women; however, hamstring muscle fatigue had a higher effect in this respect. Moreover, it affected the proprioception of the knee joint position at the flexion-extension angles of the knee joint range of motion.