---

Background and Objective: One of the most common malalignments of the knee joint is valgus. This study was done to determine the effect of using graded knee brace at two angles of 60 and 30 degrees on the ground reaction force components in males with genu valgus during landing.
Methods: This clinical trial study was done on twenty males with genu valgus with age range of 21.70±2.12 years. The graded knee brace was used in two flexion angles of 60 and 30 degrees. Landing from a platform with 40 cm height on a force plate was done during three conditions including without brace, with a brace at flexion angles of 30 and 60 degrees.
Results: A significant reduction was observed in the vertical force during contact phase while landing with brace at a 60-degree angle compared with landing without brace by 15.21% (P<0.05). Also, the peak of medio-lateral force during the heel contact phase while landing with knee brace at 30 degree was significantly greater than that landing with knee brace at 60 degree by 27.18 % (P<0.05).
Conclusion: By reducing the knee flexion angle, the forces of the lower extremities increase and this issue could possibly increase the risk of injury in the knee joint. Therefore, the use of this type of brace is recommended for individuals with genu valgum at a 60 degrees limiting angle.

---

Background and Objective: Genu valgum is one of the most common lower limb malformations that affects on walking mechanics. This study was done to evaluate the effect of corrective exercise with Thera-band on the lower limb muscles’ co-contraction in males with genu valgum during walking.
Methods: In this clinical trial study, 24 male students with genu valgus with age range of 20-30 years were randomly divided into two control (n=12) and intervention (n=12) groups. Using the caliper, the intensity of the genu valgum was measured by assessing the distance between the medial malleolus of the subjects. Corrective exercises were performed for 8 weeks using Thera-band in interventional group. The electrical activity of selected muscles was recorded by electromyography system (biometrics ltd, UK).
Results: In the interventional group, the knee joint flexor/extensor directed co-contraction was increased significantly during the heel contact phase in the post-test than that in the pre-test (P<0.05). There was also a significant increase in knee joint general co-contraction during heel off phase (P<0.05). In the interventional group, directed co-contraction of vastus lateralis / vastus medialis muscles during the swing phase was significantly increased during the post-test in compared to the pre-test (P<0.05). During post-test, knee joint flexor/extensor directed co-contraction during the heel, knee joint general
co-contraction during heel off phase and directed co-contraction of vastus lateralis / vastus medialis muscles during the swing phase were more in the interventional group in compared to control group (P<0.05).
Conclusion: The increase of general co-contraction in the knee joint during the heel off phase reflects an improvement in activity of the knee support muscles after corrective exercises and increases balance and stability. There was also an increase in the knee joint flexor / extensor direction co-contraction, which increase the distribution of the load and pressure between the femur and tibia in the knee joint.