Heart rate is not a component of skill-related fitness. Option D
The focus of skill-related fitness is on characteristics that improve performance in particular physical activities. Options A, B, and C—balance, speed, and power—are essential elements because they have a direct bearing on a person's capacity to perform well in activities involving strength, agility, and coordination.
Although heart rate is an important component of cardiovascular fitness, it is more closely tied to health-related fitness than skill-related fitness, which focuses on factors that are directly related to athletic ability and motor skills.