What are some tips for improving my running speed and endurance, and how can I incorporate these into my training routine? Your response should contain at least 5 sentences. In your response, the word "training" should appear at least 3 times. Highlight at least 2 sections in your answer with markdown, i.e. *highlighted section*. Include keywords *workouts, *rest, *recovery, *pace, *interval, *strength, *flexibility*.

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