This year, set a goal that can actually help you sustain an exercise habit.. January can be an excellent opportunity to reset, but many fitness resolutions — like sculpting a six-pack or losing a lot of weight — can be unrealistic or unsustainable. When taken to extremes, they can also end up hurting your body image, mental health and metabolism.. This year, consider a fitness resolution that has nothing to do with how you look. Focus on learning a skill, accomplishing a physical feat or simply building a habit. These can all help you develop intrinsic motivation, or the desire to pursue something because it is inherently satisfying or enjoyable.. The key is setting a goal that’s the right size, said Karin Nordin, a mind-set and behavior change expert. “I always recommend setting a goal that challenges you a little bit, feels a little intimidating and even scary,” she said. But it shouldn’t be so challenging that it feels impossible, she said. On a scale of one to 10 for how achievable it feels, she suggested aiming for a goal you would rate an eight or higher.. Dr. Nordin also recommended giving yourself a “prototype period” to help you refine a longer-term goal. You can tell yourself: “In January, these are the resolutions I’m going to try on,” she said, “like putting on a sweater in the store before you buy it.” Maybe that’s a month of a weekly Pilates class, or two weeks of a gentle warm-up before each workout. See how it goes, and then decide if you need to readjust.. Here are five resolution ideas to get you started.. Work toward a pull-up.. Pull-ups help improve upper body, back and grip strength, as well as core stability, and they require mobility through multiple joints. They’re a difficult exercise, but there are good ways to work up to a pull-up or to modify it to be easier.. Start with exercises to strengthen your biceps, triceps, lats, shoulders, hands and core, said Maillard Howell, a personal trainer and gym co-owner in Brooklyn. “There’s a whole cast of supporting characters that has to sync for you to do a pull-up,” he explained. Exercises like bicep curls, lat pull-downs, dead hangs from the bar and core strengthening movements can all help.. We are having trouble retrieving the article content.. Please enable JavaScript in your browser settings.. Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.. Thank you for your patience while we verify access.. Already a subscriber? Log in.. Want all of The Times? Subscribe.