Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to get stronger [title] Challenge yourself with every workout. [step] When your aim is to gain strength, working out should never feel easy. In fact, that 30 minute to 1 hour period you spend lifting, pulling and pushing weight every day should be extremely uncomfortable.

Ending1: Therefore, to make the most of the available time remaining for strength training, make sure to work out as much as possible in the 30 minute deadlines and days you choose to work out. Remember that you are raising your strength through individual movement and a bit of resistance. Ending2: There are lots of other ways to get stronger. As a rule, do each exercise for 30 minutes and do some rest breaks afterward. Ending3: If it's not, you aren't putting enough stress on your muscles to help them grow stronger. Challenge yourself to " go all in " with every single workout to see maximum results over time. Ending4: Whenever you feel ready to work out and are just about to quit altogether, do it. Ask your doctor or trainer for some assistance.

Answer format: ending1/ending2/ending3/ending4