Pilates/Core, Strength, and Yoga

Participating in a Group Exercise class is one of the most enjoyable and effective ways to get fit! All fitness levels are welcome. Various intensity levels are shown for every exercise. Class sizes are 3-10 people, so you’ll always receive plenty of personal attention and instruction. There is no hiding in the back of our classes!

Your first class is complimentary, and you will receive a welcome gift bag and a tour of the studios.

Our setting is positive and nurturing, no matter your fitness level. Our goal is to build your confidence and allow you to challenge yourself safely. The small studio setting encourages you to be consistent, and the group atmosphere holds you accountable in a positive way. Yes, we do notice when you miss class!

Click here for more Information on Yoga 

Click here for more information on Pilates Equipment classes


Strength Training 

A 60-min total body strength workout using various dumbbell, body bar, resistance band, medicine ball, TRX, BOSU ball, kettle bell, and body weight exercises to strengthen every muscle group. Circuits and tabatas are also incorporated into this strength class.

This functional class allows you to train all movement patterns, and is a fun and challenging way to improve your fitness level. All ages and fitness levels are welcome; progressions and regressions are shown for each exercise.


Tuesday 7:30am/8:30am

Thursday 7:30am/8:30am/5:30pm                          

WHERE: Studio West-FBD Grand Ave.

Click here to view class schedule & sign up for class via MINDBODY.


Drop-In Strength Classes
Strength Class Packages

 8 Class Package $110

16 Class Package $210

Click to purchase

We encourage you to exercise consistently. It is your responsibility to come to class! To allow you some flexibility, 8-class pkgs expire 3 months from date of purchase and 16-class pkgs expire in 5 months.


Unlimited Class Pass

$155/month (includes Yoga, Strength Training, & Core Conditioning classes)

Click to purchase 

Cancellation Policy


Clients who are signed in for Strength, Yoga, or Core Conditioning classes must cancel their place online in that class at least 24 hours in advance of the class time. Any class cancelled less than 24 hours in advance will be charged in full.

Unlimited Class Pass:
Clients who use an Unlimited Class Pass are allowed 2 late cancels a month. After that, a late cancellation fee of $10/class will be charged to your account.

Core Conditioning

Core includes all major muscle groups from your knees to your shoulders! This class includes core exercises using props such as body wt, fitness circles, DBs, balls, and bands to challenge you.

Class size limited to 4 clients in the studio. We encourage you to exercise consistently. It is your responsibility to come to class and get results!
Contact Barb Mendoza to register or feel free to drop-in.
Saturday 10:15 am - Studio West

Click here to view class schedule & sign up for class via MINDBODY.


Core Conditioning Class Drop-In
Core Conditioning Class Packages
$110 8-class package
To allow you some flexibility but still hold you accountable to attend class regularly, our  class packages have an expiration date. Please check when you purchase your package.
Unlimited Class Pass

$155/month (includes Yoga, Strength Training, & Core Conditioning classes)

Cancellation Policy

FBD-Grand Ave Location

Clients who are signed in for Strength, Yoga, or Core Conditioning classes must cancel their place online in that class at least 24 hours in advance of the class time. Any class cancelled less than 24 hours in advance will be charged in full.

Unlimited Class Pass:
Clients who use an Unlimited Class Pass are allowed 2 late cancels a month. After that, a late cancellation fee of $10/class will be charged to your account.

What our clients are saying...

If I can point out one obvious gift from God, it's having Mary St. Onge as my yoga instructor. She's a perfect fit, like a tailor made suit. She does not merely go through the motions of yoga. She plants seeds of wisdom, she explains the physical/emotional benefits of the yoga poses and is always mixing it up so you are constantly learning. I love how we actually breathe through poses slowly as opposed to sweeping through them like a hectic day. Mary is passionate about what she teaches and with that kind of energy, you get so much more from your practice. She's awesome! – Yoga Student
One of the best decisions of my life was to start personal training at Fitness By Design. I feel so much healthier, more energetic and have a more positive outlook on life. What could be more important? If you are looking for a personal trainer, you have found the very best with Barb Mendoza. She deeply cares for every client and customizes a program that delivers terrific results. – Client of Barb Mendoza
I started practicing yoga at a very vulnerable time in my life and in Mary's classes I have learned how to heal myself from within and that it's ok to take care of me first.Through the practice of yoga under Mary's guidance, I have gained more confidence in myself to handle whatever life sends my way.  I feel such inner peace every time I leave one of her classes that I can't wait for the next one. Mary is very passionate about yoga and brings that passion into every class she teaches. I highly recommend Mary to anyone who is looking for peace and serenity in their life. – Carol
Last year, I decided to take more initiative with my health. I have been working out with Barb once a week and have recently added 2 fitness classes. I've been very adamant about taking this slow and steady- I want to change how fitness occurs as a long-term commitment. I can say that the variety of activities I participate in through FBD and the exercise I do on my own have really made a difference in my daily life. I'm stronger, more fit and have even noticed that my clothing fits better. Fitness By Design has been an all-around great addition to my life. – PT Client
I am really enjoying my yoga classes with Mary. I've never done yoga and I couldn't have asked for a better instructor for my first experience. Mary is fantastic - she has a very calming effect on my mind and body - can't wait for Monday evenings! – Client of Mary
As a mother of 3 young boys, it is difficult to find time to work out. I know that when I work with Barb, I will get maximum results in the minimum time. Barb has learned a lot about me and knows what to focus on so I get the most out of my workout. She is incredibly motivational and I appreciate her dedication to, not only my health, but my family's health as well. – RKM, West Des Moines
Yoga's a great way to exercise & relax both the body and the spirit. – Karen, Client of Mary
I have been working out with Tim O'Neil since the first of May, 2005 and achieved great results!! Overall, I have lost 5% body fat, 10 pounds fat mass, and 8.75 inches in measurement. I have tried many diets and programs from Atkins to Weight Watchers and have never achieved long-term success. Tim provides great leadership, a very positive attitude and raises the bar each month. I am confident he has helped me fundamentally change my behavior and my improved appearance, energy level and overall health is permanent. – Steve L., Client of Tim
My lungs always feel so expansive the next day, my brain is calmer, and I've lost 9 pounds! There's just something about mindfulness, energy, and quiet that is so wonderful. AND I would like to say: You, Mary, are the BEST! I've been to other yoga classes, and they just don't have the same "spiritual" tone. But it's not preachy... just simple and nice. Also, I don't ever feel that I am in danger of injuring anything. You always focus on just doing what you can without hurting anything which is perfect for me!! – Client of Mary
I have been going to strength training classes for over a couple of years now. I enjoy exercising with a nice group of people and have found the class very helpful at both improving my running and preventing injuries. Best of all....I can now see my triceps – Strength Class client
You go above and beyond to give everyone individual attention and your dedication to making your studio great is obvious. I have worked out at many places in the last 30 years and hands down yours is the best I've been to. The classes are never the same and always challenging. I love going!!  – Kathy
My journey to a healthier life has been a slow one, and Barb has supported me all the way, pushing me when I needed it, helping me noticeably increase my balance, agility, functional strength, and confidence. This year I decided to focus on weight loss. Barb held me accountable to that, celebrated small successes with me, and helped me keep the inevitable setbacks in perspective. I've lost 20 pounds, and we're still going! – Client of Barb
You have the best staff ever, Barb! So grateful to have the opportunity to improve my barre practice at FITNESS by Design! – Private Client
I have attended both the strength training and Yoga classes and feel challenged in both!  The routines provided by the instructors are varied and we are engaged at all times...I must also say I enjoy socializing with neighbors and friends when I am there and would highly recommend taking advantage of the first free session.  – Shelley Brody
Just wanted to let you know how much I've been enjoying the mixed-use yoga classes with Mary! It's a highlight of my week and I THINK I may be progressing a bit in my practice -- it's not as foreign to me now, and I've even ventured closer to the mirror and the front of the room. :)   – Yoga Client
Just loved the work with stretch bands, as did others. It was a hard class, harder than usual, which I think we all want. And as older ladies we all have problems with opening up our hip flexors and staying limber. I think we need to all sweat a little bit more too! – Kathy
I liked the Tuesday night mat class a lot. Janice is always appropriately challenging and is great at cueing. She is a real pro! I was concerned that I would be sore doing Pilates the same day as Strength and it hasn't been a problem. – Diane
We're both really happy with how things are going. Amy makes it fun and pushes us, but is also attentive about any pain spots and making sure we don't aggravate anything.   – PT Client
I joined FBD in late June and I have lost around 8 inches with my trainer, Janice. I find the experience very rewarding and believe I have increased my stamina and strength. I will continue on this path and see where it takes me. I can be a fairly impatient person as far as results go , but know Rome wasn't built in a day....so it's full steam ahead! – PT Client
Instructors have been great. They know what they are doing. They help adjust me, and I appreciate that. Like the small/intimate setting and that there is a "sense of community." I like that I just have to bring myself, no equipment, and I am very impressed with all the equipment. People are friendly. I love the variety of options/classes, yoga, pilates, barre etc. Facilities are clean and smell good. – Class Client
Mary does such a good job of making sure I, and everyone, is comfortable. So glad I took the leap and signed up! – Yoga Client
Desiree is so welcoming and encouraging. And the space is so cool - I would never have guessed how big it is from the outside! Looking forward to my sessions! – PT Client
My training sessions have been most important for my health and well-being. My trainer, Desiree, is excellent. She is knowledgeable, organized, safety concious, adaptable, patient, but knows how to push one towards improvement and progress. The studio is private, well equipped, and close to home, a plus for me. The staff has always been kind and fun. The experience has been well worth the money! – Nancy
I am so fond of your teaching staff. – Class Client
Desiree is our trainer. She rocks! Don't have enough good things to say. My husband and I are having the best time together working towards our personal goals. You can tell how passionate she is about what she does helping her clients achieve the results they are shooting for.  – Amanda