Footwear is postulated to be the key factor affecting running performance and injury risk. The primary objective of this study is to investigate the effect of accumulated running distance and shoe cushioning hardness on the peak muscle activation force for Malaysian amateur runners using the musculoskeletal model. Ten healthy Malaysian male amateur runners were recruited into this study (age: 29.2 ± 3.52 years; height: 1.72 ± 0.05m; weight: 70.05 ± 6.91 kg). The study examined two running shoe cushioning conditions: (i) soft cushioning with a shore hardness of 32A and (ii) hard cushioning with a shore hardness of 42A. Participants were required to accomplish three accumulated running distance milestones (40km, 80km and 120km) with a minimum of 10 km running distance per week. The muscle groups tested for this study are Bicep Femoris, Lateral Gastrocnemius, Rectus Femoris and Tibialis Anterior. Gait models for running were developed using Opensim, with muscle activations being estimated through the static optimization method. Results show that hard cushioned shoe demonstrates greater peak muscle force, which could benefit short distance running. Additionally, this study shows that 80km of cumulative running distance should be used as a threshold guideline for replacing the running shoe for both hard and soft cushioning running shoes as the peak muscle force for RF increases by 34.63% in hard cushioned shoe and 32% for soft cushioned shoe. Future direction of this study should involve female runners and different age groups to conduct a comprehensive investigation into the potential impact of gender and age.