Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to exercise to become a better swimmer [title] Plan a swimming routine. [step] You don't need to work out everyday, but try commit to at least three days a week. Decide what time works best for you.

Ending1: It's a good idea to start when you know you're going to be swimming for the first time and schedule your rest between that time and the workout time you've scheduled. [substeps] Avoid starting when you're feeling sore or tired. Ending2: Otherwise, you may find yourself frustrated or bored. Most people should start this routine between the ages of 28 and 57 to moderately improve their swimming skills. Ending3: Whatever your work out schedule is, make sure you commit to it every day. [substeps] To calculate how much time you need to exercise, multiply this number by the number of laps you're able to take. Ending4: Some people find it helpful to swim before work, while others benefit more from swimming after work. It just depends on what your schedule is.

Answer format: ending1/ending2/ending3/ending4