A 21-year-old student comes to the university health clinic due to left knee pain. For the last 3 weeks, she has had aching, poorly localized anterior knee pain that is worse when standing up from a low chair or when sitting in class for extended periods. The patient plays on a club softball team but is unable to play through a complete game due to the pain. Her medical history is unremarkable, and her only medication is an oral contraceptive. She does not use tobacco, alcohol, or illicit drugs. Temperature is 36.9 C (98.4 F), blood pressure is 118/70 mm Hg, and pulse is 68/min. BMI is 17 kg/m2. Inspection of the knee and leg is normal with no erythema, swelling, or obvious deformity. Active and passive range of motion is normal. Quadriceps strength is normal and symmetric, but squatting reproduces the pain. No focal tenderness is noted on palpation of the knee. Which of the following should be recommended to the patient at this time?