Please choose the correct ending to complete the given sentence: Health: [header] How to stay entertained on a treadmill [title] Do interval training. [step] Spend 1-5 minutes doing hard, fast, or steep running on the treadmill followed by 1-5 minutes of slower, less steep, or easier jogging or walking. Continue to alternate between the 2 types for your entire workout.

Ending1: [substeps] Incorporate a cardio workout while jumping up and down as high as you comfortably can in 20 minutes and briefly pause during each lap. Do 10 more repetitions of the same workout in 20 minutes. Ending2: This will allow you to get a more effective cardio workout in less time. [title] Try running a fartlek on the treadmill. Ending3: [substeps] Moderate jogging : 1 1/2 minutes jogging at a rate of about 70 %. Jumping and holding on to hard surfaces will help propel you forward. Ending4: [substeps] Interval training not only helps you burn more calories in the first week, it also increases your oxygen intake. Make sure to avoid exercising for 30 minutes for the rest of the week.

Answer format: ending1/ending2/ending3/ending4