Which of the following is a method for monitoring training load?

Heart rate monitoring is a recognized method for monitoring training load, as it provides real-time feedback on the intensity of exercise. By measuring heart rate during training sessions, athletes can gauge how hard their body is working, which can be crucial for ensuring they are training at optimal levels to improve performance. This data helps in adjusting training intensity, volume, and recovery periods to prevent overtraining and injuries.

In contrast, weight tracking can reflect changes in body composition over time but does not directly indicate the training load on the cardiovascular or muscular systems. Diet logs are useful for understanding nutritional intake and its impact on performance but do not measure training intensity or volume. Activity calendars might help in tracking physical activity frequency but lack specificity in monitoring the physiological response to training. Thus, heart rate monitoring stands as the most effective method among the choices for accurately measuring training load.