We learn and grow through challenges, and our bodies are no exception. No challenge means no growth.

If you have been working out consistently but not seeing much change in your physique, then your current program is ineffective — or has lost its effectiveness as your body adapted to the demands.

Many years ago, I hired a personal trainer who was a professional bodybuilder. Having been a cardio queen for too long without seeing results, I was serious about changing my physique and seeing what my body was capable of.

Three times a week, trainer Dan pushed me to my limit and, holy cow, did my body respond. I leg-pressed 360 pounds, chest-pressed my body weight, and dead lifted well over 100 pounds. It was the strongest and most defined my body had ever been.

I was miles out of my comfort zone every time he trained me, but I grew to love the challenge and pressure of our sessions. These workouts motivated me to become a trainer myself. (Dan, if you are reading this, thank you.)

Rising to the challenge and pushing myself with these workouts did not just transform my body. My entire life changed for the better. So can yours.

I ask new clients if they currently work out. The most common answer is, “Yes, I walk regularly.” Wonderful, but it’s not enough. Continue walking, but if you want changes in your body shape and size, you need to build muscle, work up a sweat and push out of your comfort zone.

This is not to say you have to lift bodybuilder weights or run 20 miles a day. Simply push your body to do more than it now does. It can be as small as biking six miles instead of five, or upping your bicep curls from five pounds to eight.

My recommendations for body sculpting:

Prioritize weightlifting. When I reversed my workout routine from 75/25 cardio to 25/75 weights, my body transformed. I lifted four days per week, and finished two of those four sessions with 20 minutes of intense cardio. On day five, I performed 45 minutes of cardio.

Increase the amount of weight you are lifting. If you are swinging the same five-pound dumbbells you were using two months ago, you are not building muscle or changing your physique. You must progress into heavier weights at regular intervals. If you are not sure how, hire a trainer or enlist in a lifting class where correct form and proper progression is highlighted. Added bonus: Heavy lifting gets the heart rate soaring, and you complete your cardio and strength workout in one fell swoop.

This also applies to your abdominals. I used to plank and crunch til I was blue in the face, but did not see the definition I wanted. As with any muscle group, increased resistance is needed to make gains in the midsection. Once I ditched the high-rep, bodyweight ab exercises and went to low-rep, weighted core moves, I achieved the sculpted tummy I envisioned.

Choose cardio that simultaneously builds muscle. While training with Dan, I opted for the stepmill at the gym and climbed at a fast pace, skipping every other step for more muscle activation in the glutes and quads. When that lost its challenge, I wore a weighted vest while stair-stepping. Not to boast, but you could have bounced a quarter off my rear, it was so tight. Pair the stepmill with heavy weight squats and lunges and trust me, you will have buns of steel.

Plyometrics (jump training) is also great for building strength and power while challenging yourself aerobically, but use caution — it’s high-impact and not for beginners. Have a solid strength base before beginning any plyometric work and don’t overdo it. Two sessions per week should be sufficient, and don’t do too many reps at a time.

Break free from your workout comfort zone. Push yourself to do more than you did last week.

Revel in your body’s strength and competency as you advance your workouts.The sculpted bod you see in the mirror will just be icing on the cake.

Catherine Bongiorno, lifttolose@hotmail.com, is a Mukilteo personal trainer and nutritional therapist who owns Lift To LoseFitness &Nutrition, www.lifttolose.com.