Genetics do play a huge role in our overall health. Do they also play a role in our demeanor? Is optimism or pessimism passed on from one generation to the next or is it strictly learned behavior? We’ve all heard the half-empty and half-joking comments, and probably made our fair share as well. Your body will never be the same after you have kids. Your eyesight will go after you turn 40. Forget about having any hair after 50. Your joints will ache, your belly will thicken, and your energy will disappear. In fact, why even get up in the morning? Is it as simple as nature trumping nurture, or does it just let us off the hook if we paint each other with the same broad brush?

Ironically, these dire predictions are offered even here in the gym, by the healthiest of the population; the 20 percent to whom exercise is an entrenched component in their daily lives. My wife Katie and her close friend, Crystal Moller, both have recently had a baby … each for the second time. Sentiments such as “you’ll never get your body back after your second baby” followed each of them for months. Both are extremely energetic, healthy and strong, and exercised religiously throughout their respective pregnancies. Their baseline going into their pregnancy was their baseline coming out of pregnancy with only a few adaptations. Eat well, get some rest. One to two hours a day of rigorous physical activity, including spinning, step aerobics, weight training and a variety of cardiovascular machines were staples throughout their pregnancies. Adapt and overcome. Both women found that due to the increase in blood cell production, they actually increased their strength and endurance over the first seven months.

Side by side in a spinning class, their legs pumping furiously, they pushed each other as Katie directed her class through a series of hills and sprints, leaving mere mortals red-faced and sweating profusely. Countless times people would seek me out, laugh and say they didn’t know if they could keep up with the pregnant ladies if this trajectory continued. They each added approximately 15 pounds of baby weight during their 40 weeks, perfect for their sizes and shapes, and then returned to pre-pregnancy weight after only a few days. Both sport rock-hard abs, toned legs and arms, and a cardiovascular system that rivals a professional athlete. Then comes the disbelief of total strangers wherever we go who say, “Wait, you just had a baby?” Others’ experiences and predictions don’t have to become your own.

I have a client who I won’t name because of the sensitivity of her fitness request. A physically fit, healthy and happy woman, she just happened to mention that she came from a long line of women with … well, with big butts. There, I said it. She said it was the last remaining piece to her fitness puzzle, but that nothing could be done about it. It’s unsolvable. A genetic curse. “One way to find out,” was my reply, and off we went. Although she had always worked hard in the gym, we began to ratchet up all physical activity and concentrate on high-intensity strength training and plyometric exercise. I’m talking about gut-wrenching, push yourself to fatigue, my legs are actually shaking, I can’t take another step, type of training here. If a class starts at 9:30 in the morning and you’re here at 9:15, make use of those very valuable 15 minutes by lunging down the hall, doing bench jumps and squats, kickbacks and wall sits. After class, join Crystal and Katie for another 15 minutes on the Stepmill. Find somebody who you want to look like, or somebody who you think has great shoulders or back muscles or toned legs, and mimic them. Ask them what works, how much time they put in, and then double it. Double up to catch up. Sixteen weeks, nine pounds, three inches off her behind and two dress sizes later, my client would now say that apparently you can change how you look and feel!

We all, to a certain extent, listen and value the opinions of our friend and neighbors and peers. However, remember that those opinions are just subjective evaluations based on what goes on in that person’s head, and not yours. Fill your head with the thoughts of people who have overcome immense obstacles and gone on to become great champions. Training your mind to relish the chance to make huge physical improvements and override the naysayers can be daunting. Try turning those doubts to fuel. Meet every doubt head-on and fight through it. I only have to look across the dinner table at my wife and her friend to see at least two subscribers to this theory.

Your body will never be the same might just be true, as Crystal and Katie are fitter than ever.