Please choose the correct ending to complete the given sentence: Health: [header] How to avoid sore muscles [title] Vary your exercise routine. [step] If you perform the same action day after day, then your muscles will grow fatigued and overly tired, instead of strengthening. Mix up your physical activities by doing both cardio and weight training.

Ending1: [substeps] If you exercise four times a week, do cardio and do weight training two days each week. If you exercise three days a week, do heavy lifting three days a week, and then walk or swim for 30 minutes outside of your comfort zone five days a week. Ending2: Here's how to do your work out : [substeps] Find an exercise partner who's similar in intensity to yours in terms of strength, endurance, and metabolism. Start slowly, then increase the intensity as you get stronger. Ending3: [substeps] Hiking mountain climbers climb rock piles toss a frisbee high into the air. You can also jog in place on a treadmill, if that's your style. Ending4: Take a yoga class, do some water exercises, or plan a quick bicycle ride. [substeps] Creating an exercise schedule will help you meet your health goals while adding variety.

Answer format: ending1/ending2/ending3/ending4