This paper investigates the effect of muscle contraction on lower extremity injuries for pedestrian walking posture in car-pedestrian lateral impact at 40 kmph. The full body model, PMALE, which was configured in symmetric standing posture, has been repositioned in the walking posture. Finite element simulations have then been performed using the PMALE in the walking posture and front structures of a car. Two impact configurations, i.e. impact on right (trailing) and on left (leading) leg have been simulated. Two pre-impact conditions, that of a symmetrically standing pedestrian, representing a cadaver and an unaware pedestrian have been simulated for both the impact configurations. Stretch based reflexive action was included in the simulations for an unaware pedestrian. It is concluded that (1) with muscle contraction risk of ligament failure decreases (2) in lateral impacts, MCL could be considered as the most vulnerable and LCL as the safest ligament (3) for a walking pedestrian, PCL would be at higher risk in case of impact on trailing leg whereas, ACL would be at higher risk if car strikes the leading leg (4) active muscles may not affect bone fracture in high speed car-pedestrian crashes.