Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to strength train as an older adult [title] Start slowly with all exercises. [step] When you're first starting or incorporating a strength training routine, it's important to ease into it. Doing too much exercise or using a weight that's not appropriate for you can cause an injury.

Ending1: [substeps] If you're already very active, you may be more likely to be vigorous and need some overall strength up. The first exercises should be challenging, but not dangerous. Ending2: Try all types of strength training to see if any changes are necessary. [substeps] If you think any changes might be a concern, try changing your exercise regimen gradually so you can get used to the idea more slowly. Ending3: Try to only do a couple of ten-minute sets of exercises a day, for example. [substeps] Strength training can be difficult if you're new to hitting and pushing weights. Ending4: [substeps] Although including two to three days of strength training is recommended, start with just one day a week. This will help you ease into a new routine.

Answer format: ending1/ending2/ending3/ending4