en Physical Therapy Physical Therapy Original Research Original Research <p> <strong> Background </strong>:This paper explores the gender-related bilateral differences of extensor and flexor torques of the knee joint at low and high angular velocities in Iranian healthy males and females. </p><p> <strong> Methods </strong>: 70 healthy subjects (29 males (26.61±4.34 yrs and 41 females with average age of 23.07±3.70 yrs)) were participated in this study. Isokinetic peak torque values for knee extensors and flexors in concentric and eccentric contraction modes were measured and flexors and extensors strength ratios (HQR) computed among both dominant and non-dominant legs in lying position at 60 and 180°.s-1angular velocities. </p><p> <strong> Results </strong>: There was significant gender-velocity interactions detected for knee flexor to extensor strength ratios presenting that increasing velocity escaled this, ratios in females more than males(p<0.05). There was no gender-velocity-leg side interaction (p>0.05). Bilateral differences were found for eccentric flexor peak torques (p<0.05). By increasing velocity, peak torque values decreased and HQR was increased (p<0.05). </p><p> <strong> Conclusion </strong>: Measurement procedures including test position is an important factor when interpreting gender- related and bilateral differences of isokinetic knee strength ratios in healthy individuals. </p> Knee, Isokinetic dynamometry, Strength ratio, Gender. 702 707 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1501-4&slc_lang=en&sid=1 Mandana Rezaei mandana.rezae@gmail.com 200319475328460013554 200319475328460013554 No School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran. Ismael Ebrahimi ebrahimi.pt@gmail.com 200319475328460013555 200319475328460013555 No School of Rehabilitation, Iran University of Medical Sciences, & Rehabilitation Research Center, Biomechanics Lab, Iran University of Medical Sciences, Tehran, Iran. Behnoush Vassaghi- Gharamaleki vasaghi.b@iums.ac.ir 200319475328460013556 200319475328460013556 No School of Rehabilitation, Iran University of Medical Sciences, & Rehabilitation Research Center, Biomechanics Lab, Iran University of Medical Sciences, Tehran, Iran. Milad Pirali milad.pirali5@gmail.com 200319475328460013557 200319475328460013557 No Islamic Azad University of Tehran Central branch, Tehran, Iran, Rehabilitation Research Center, Biomechanics Lab, Iran University of Medical Sciences, Tehran, Iran. Niyousha Mortaza niyusha_m@yahoo.com 200319475328460013558 200319475328460013558 No Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia. Kazem Malmir kazemmalmir@gmail.com 200319475328460013559 200319475328460013559 No School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran. Kobra Ghasemi koohestan_3000@yahoo.com 200319475328460013560 200319475328460013560 No School of Rehabilitation, Iran University of Medical Sciences, Tehran, Iran. Ali A. Jamshidi aliajamshidi@yahoo.com 200319475328460013561 200319475328460013561 Yes School of Rehabilitation, Iran University of Medical Sciences, & Rehabilitation Research Center, Biomechanics Lab, Iran University of Medical Sciences, Tehran, Iran.