To focus on adding anaerobic exercises to her training routine, Karolina should consider adding weightlifting. Anaerobic exercises are typically high-intensity activities that can be performed in short bursts, and weightlifting fits this description well. It primarily relies on energy sources that do not require oxygen, making it a key component of anaerobic training.
While activities like sprinting or certain types of interval training are also anaerobic, weightlifting is the most straightforward option among the choices given.