Artificial muscles made of nylon fishing strings can be actuated using heating and cooling or induced electrically or thermally. These nylon fishing strings show promise in replacing the bulky and expensive actuators that are typically used in robotic prosthetic, as they are lightweight and relatively low in cost. The lifespan and performance of these artificial muscles need to be identified for further development in the use of prostheses and artificial muscles. In this research, we conducted experiments, where the nylon strings that have been coils into Super-coiled polymer (SCP) were tested after going through four different conditions of annealing process. these strings are then tested in lab-based rig to be checked for durability and performance. From the result, we discover that using Slow heating slow cooling (SHSC) annealing process makes the artificial muscles become more durable and while the string undergoes Fast heating fast cooling (FHFC), it can exert higher force comparing to other approaches. This result proves to be useful in deciding the most suitable process to prepare the string to obtain the best performance for the use in robotic prosthetic.