Consider an experiment where a subject lands during two conditions from a height of 0.2 m. During the first landing condition, the subject lands 'stiffly' (e.g., very little knee flexion). During the second landing condition, the subject lands 'softly' (e.g., lots of knee flexion). During the soft landing, the peak vertical forces are less than during the stiff landing. Which of the following statements best explains this observation?