What strategies do experienced MTB riders employ to maintain their physical and mental well-being when faced with prolonged periods of riding in wet and muddy conditions, and how do these approaches impact their overall performance and recovery? Are there specific techniques or training methods that can help mitigate the negative effects of mud and water on the body, such as reduced muscle function and increased energy expenditure? How do riders balance the need to push themselves in challenging conditions with the risk of injury or burnout, and what role do factors like bike maintenance, gear choice, and course selection play in this equation? Are there any emerging trends or technologies that are helping to make muddy MTB riding more sustainable and enjoyable, and what can riders do to stay ahead of the curve in terms of preparation and adaptation?