What can excessive fatigue during training indicate?

Excessive fatigue during training is a significant indicator of potential overtraining. Overtraining occurs when an individual trains at an intensity and/or volume that exceeds their body's ability to recover. This can lead to a variety of physical and psychological symptoms, including prolonged fatigue, decreased performance, and other negative side effects such as mood disturbances or increased risk of injury.

When a trainer or athlete experiences excessive fatigue, it suggests that the body is not adequately recovering between training sessions, which can hinder progress and overall health. Recognizing this sign is critical for adjusting training programs to ensure that athletes can recover effectively and avoid the plateau or decline in performance associated with overtraining.

The other choices relate to positive training outcomes, such as increased efficiency or improved performance, which contradict the implications of excessive fatigue. Likewise, lower energy expenditure does not correlate with the experience of excessive fatigue, as fatigue typically arises from intense and sustained effort rather than a lack of energy output.