It is possible to enhance the effects of regular physical activity by altering the type, duration, frequency, intensity, or progression of exercise. Match the situations to determine whether they are describing increasing duration, frequency, intensity, or progression of exercise: Bill was swimming for 30 minutes, 3 days per week and recently increased that to 45 minutes, 3 days per week: (Click to select) Sonya was participating in one aerobics class per week and recently increased that to two aerobics classes per week: (Click to select) Erin was walking on the treadmill at a rate of 3 miles per hour for 60 minutes and recently was able to increase that to 4 miles per hour: (Click to select) Chris used to do 30 minutes of cardio at 50% of his max heart rate 2 days per week and has gradually increased his performance such that now he is exercising for 60 minutes at 80% of his max heart rate 4 days per week: (Click to select)