Team Soul.Train.

Jonathan Medeiros

Soul.train. Owner; Certified Personal Trainer ACSM, NASM, Kettlebell, Crossfit level 1

As owner and founder of soul.train. A Mind & Body Fitness Studio, Jonathan Medeiros’ mission is to bring excitement surrounding fitness/wellness to the community. A lifelong resident of the Cambridge/Somerville area, it is important that the communities closest to him are able to benefit from his passion and knowledge of fitness.

First certified as a Personal Trainer in 2001, Jonathan has worked in both private training studios and large corporate gym structures. Right before opening soul.train., Jonathan worked as a Master Trainer and Fitness Service Manager for TSI. His current certifications include but are not limited to: ACSM (American College of Sports Medicine), ACSM Advanced Trainer, NASM (National Academy of Sports Medicine), NASM Corrective Exercise Specialist, Kettlebell Concept Instructor, and most recently Crossfit Level 1 Instructor. He has also coached wrestling and football and still competes in football today.

His primary source of motivation has been watching is only sibling, Kristina, overcome every physical obstacle that she has been presented with. Kristina has Down syndrome but has been able to compete in sports, particularly gymnastics, at a high level. She not only has won over 100 medals competing in the Special Olympics, but also competed at the high school level for Cambridge. Proof that anything is possible when it comes to overcoming physical obstacles.

When building and designing soul.train. himself, he wanted to be able to deliver a wide variety of opportunity for functional movement training. His philosophy behind functional training (functioning outside of the gym) is improving overall quality of life while also reaching personal goals at the same time. Realizing that there are so many of genres of people and genres of training, Jonathan wanted to be able to reach everyone with soul.train. This is why the facility is designed the way it is called “soul.train.” There are two levels at soul.train., the top level is where the group exercise classes are held and is the “soul”, inspired by our yoga program. The downstairs or “train” is where most of the personal training takes place and is inspired by olympic lifts and kettlebells. Although a certain philosophy is kept, he is not limited by it when it comes to delivering specific training to whomever. His clientele ranges from teenage athletes to senior citizens who may be rehabilitating from injury and everything in between.

Erica Bornstein

Yoga and Dance Instructor

Erica Bornstein is a yoga and dance teacher, choreographer, and lover of all movement. She fell in love with yoga at a very young age when she was introduced to it as a way to stay in top dancer shape, but later in life discovered it was so much more than that. As an adult, she developed a regular yoga practice, and noticed that it brought her to feel this sense of balance in her body and her mind. Other physical activity became easier, and she approached difficult situations in life with a much more open attitude. Erica found herself constantly talking to people about yoga, thinking about yoga, reading about yoga, so she decided to see what would happen if she registered for a teacher training in 2010.

Erica now is a full-time yoga teacher and could not be more thrilled to be a part of the incredible yoga community in Boston. Erica teaches an athletic vinyasa flow, with focus on basics and alignment, with some advanced options sprinkled in, and she encourages students to personalize their practice for their own needs. She teaches yoga with a sense of fun and creativity, always has a killer playlist, and her humor and playful spirit is ever present in her classes. Overall, Erica believes that yoga is an accommodating practice, accessible to all people, that requires only loving care for the body and the willingness to keep an open mind and heart. Her number one mission in life is to encourage everyone to love yoga, or at least to try it. Among her many teachers, Erica is indebted to Chanel Luck, Bonnie Argo, and Lynne Begier and is continually inspired by so many of the teachers in the local Boston yoga community who are truly amazing.

In addition to yoga, Erica wanted to find some way of keeping her foot in the door of the dance world, so she started teaching Zumba Fitness. Her Zumba classes are unique because of her extensive dance training which makes the choreography interesting and extremely high energy, so come prepared to WORK, smile and sweat during all of her classes!

Kristin Khederian

Yoga Instructor & Marketing Director

Kristin started practicing yoga several years ago because she was bored and uninspired with her current gym routine and wanted something that challenged her physically but also offered a mental release from the stresses of everyday life. After just one class, Kristin knew that Yoga was what she was looking for. Hooked ever since, Kristin believes that her days are not complete until she has been on her mat. She feels that Yoga is truly so much more than just a physical practice, but rather a sacred time to work her body and mind in ways that she never thought possible.

Kristin’s teachings are influenced by many styles of Yoga including Vinyasa, Smart Sequence (Kula) Flow and Prana Flow. Her classes are fun and energetic and encourage freedom and expression through movement, while still emphasizing safe alignment. You will sweat, laugh, flow to some great tunes and will certainly leave with a sense of renewed energy and clarity that will radiate throughout the rest of your day. Kristin believes that Yoga is for every body and if you commit to your practice, the results can be life changing.

Kristin is a RYT 200 and pursued her certification from the Radiant Yoga School in 2010 under the instruction of Chanel Luck and Bonnie Argo. She also completed a Mentorship with Georgia Reath in the Winter of 2013. Always a student first, Kristin continues her studies today with Ame Wren, David Vendetti, Todd Skoglund, Georgia Reath, Joanne Flaherty and many other amazing and influential Boston area teachers.


Pilates and Barre Instructor
After dancing for twelve years, I started taking barre and yoga classes and developed a great love for barre and found a much deeper mind-body connection than dance alone. I received my barre certification in Summer 2015. Currently, I am studying Holistic Psychology at Lesley University and hope to go on to teach barre and yoga as alternative therapies in the future. I always enjoy taking and teaching barre classes and I love sharing all the physical and mental benefits of barre with my students whenever I can!

Lauren Hefez

Group Exercise Instructor – “Sweat with Lauren”

Lauren grew up dancing and has taken her passion for dance and wellness and turned it into a successful career in group fitness. She teaches her popular signature class “Sweat with Lauren” that focuses on creating the long lean lines of a dancer. Her classes are filled with crazy high energy and she is known for her no weighted arm series and killer butt work. Lauren is pre and post natal certified.

Aside from teaching Lauren is a fitness model and has a successful YouTube channel!

Kourtney Petty

Personal Trainer
Hi, I’m Kourtney! I have always led a very active lifestyle and had a passion for fitness, but after my two years of college basketball I let my fitness slip and was not liking the way I felt. While finishing up college I started working at the front desk of a sports club and had a regained passion for fitness. I loved the healthy and positive environment, and learning fun new tricks of the trade from the trainers there. It was then I decided that this was the path I wanted to follow.
I became a NASM certified trainer a year and a half ago and certified in TRX last January. My favorite part about training is seeing progress and new found confidence in clients.
In my Nasty 9′s class you can expect a fun yet challenging workout environment with a balance of cardio and weight training. This class is tailored for all levels, you do as much as you can for each of the 20 seconds! My teaching style is to positively encourage you to continue to push yourself to get the best out of each workout. I want you to leave having had a great time and a great workout!

Maeve Byrne

Zumba and Pilates Instructor

Maeve has has been dancing her whole life… growing up in jazz classes, cheerleading…and joining the Kickline team in college – dance has always been a major part of her life. Years later, fitness and dance are even more important to her. After a long and stressful day at work she knows there’s nothing like dancing it all away and getting in shape! She discovered Zumba and fell in love! By learning fun, sexy dance moves and burning calories, she soon forgot it’s a workout and began to think of it as a dance party!

Maeve has been listed as one of the Top 3 Zumba Instructors in Boston 2 years in a row and hopes everyone will fall in love with Zumba as much as she has! Every class is a party and all you have to do follow her lead – it’s that simple!
For more info on Maeve, visit her Facebook Fan Page.


Scott Costello

Certified Master Personal Trainer NCSF, Kettle Bell Instructor KBC, Weightlifting Sports Performance Coach USAW, Certified in Pre/Post Natal Training

Scott has been involved in sports and athletics since the age of eight and began weight lifting at the age of 17. Scott’s passion for sports and weight training continued after high school and he has embraced all aspects of fitness as a lifestyle. Scott’s workouts are intense and diverse with a variety of techniques and styles. He feels it is important to teach his clients proper technique and form, when it comes to exercise, so they have fun and feel safe at the same time. Scott works with all ages and fitness levels, and gears workouts towards his clients’ particular goals and interests. Through a combination of strength training, conditioning, mobility and nutritional guidelines, his goal is to educate his clients to become the best versions of themselves that they can be. He constantly strives to learn more about fitness and how he can apply these new concepts into his clients’ workouts.
Fern Bent-Mullings
Personal Trainer

I have been a personal trainer since 2007 and am certified by the International Sports Sciences Association (ISSA).
I love working with all types of people, including those recovering from injuries, senior citizens, and especially brides to be! I feel that having the ability to push someone to limits they would not do themselves is extremely rewarding. I love what I do and would not have it any other way!




Chris Belloste

Boxing, Crazy 8′s, and Personal Training
Chris has always had a passion for sport and fitness and found his niche with boxing 4 years ago. He has trained, competed, and coached at local boxing gyms and has now brought his interpretation of a Boot Camp style Boxing class to Soul.Train.! Being born and raised only minutes from Soul.Train., he has a true commitment to the community and those who live in it and can’t wait to share his fitness style with us. His two sons keep him on his toes and competitive, but also teach him patience and compassion, which enables him to be successful with any client type. So whether you have boxing experience or not, Chris will teach you and make it fun at the same time. Although Chris loves Boxing, he is not limited to that single style of training. He is an experienced all around trainer and is available for Personal Training no matter what your goals may be. He’s looking forward to seeing you soon!



Yoga Instructor
Olga teaches a slow, mindful Vinyasa class that’s deeply grounded in balancing between breathe work, alignment, spirit and a good flow. She values life’s little joys, laughter, and not taking one’s self too seriously. She believes that yoga should a space that’s serious about alignment and joyful in practice. Her classes allow the mind to restore from the everyday chaos and leaves the body balanced.  Her classes are achievable for practitioners at every level. She has studied with Sue Jones, Pat Iyer, Jacqui Bonwell, and David Vendetti.
When she’s not teaching yoga she keeps her soul smilin’ with her dedicated yoga practice, running away to the wilderness in her free time, and practicing gratitude. She loves finding things to climb, people to hug, and harnessing her inner domesticated side.