Hormonal

Prior endurance or strength training history attenuates the acute phosphorylation of AMPK and Akt signaling pathways in response to divergent exercise stimuli, indicating that chronic adaptation blunts specific early signaling responses to non-habitual training modes.

If you are already well-trained in one type of exercise (e.g., running or weightlifting), switching to a different type (e.g., lifting or running) will not trigger the same intense initial signaling response as a beginner would experience. This does not mean the new exercise is ineffective; your body is simply more efficient. Focus on consistency and progressive overload rather than chasing acute 'burn' or signaling markers, as your adapted muscle handles stress differently.