A recreational runner currently runs 3 × 30 minutes per week at an easy pace. Their goal is to prepare for a 5K in 8 weeks while minimizing injury risk. According to progressive overload, which multi-step plan is best?

• A. Immediately double weekly mileage and introduce daily speed work to accelerate adaptation quickly, since rapid overload produces faster improvements even if brief aches result.
• B. Switch abruptly to cross-country skiing for all sessions because changing type of exercise is the best way to quickly overload multiple systems simultaneously.
• C. Gradually increase one training variable at a time: add one extra 20–30 minute run every 2–3 weeks (increasing frequency), slowly add 5–10 minutes to one run every week for duration, and introduce a single session of light intervals after week 4 to increase intensity, while keeping total weekly increases modest.
• D. Keep frequency the same but hike intensity to near-max HR in every run from week 1 to build cardiovascular capacity fastest, while not changing duration.

Answer: (C)