Justin Killeen, M.S.

Early in 2012, I was driving around Amherst, Hadley, and Northampton looking for local gyms that may be hiring. I was a (relatively) experienced trainer, recent UMass graduate, and circumstances led me to stay in the area longer than I originally anticipated.
I came across a small gym called “Energia Studios”, nestled in next to Hillside Pizza on Route 9. To be quite honest, I think it was because I was getting a slice of pizza for lunch that day. I was intrigued by it, but each time I returned (not for pizza!), the lights were out and the door was locked. Finally, frustrated, I left my resume taped to the door.
Several weeks later, I got a call back, interviewed, and was hired as the personal trainer. I began two other jobs as well. Eventually, I decided that none of it seemed right for me. On a whim, I started “Pioneer Valley Fitness”, what was a mobile or on-site personal training business. I began to really grow as a personal trainer, working with dozens of people out of their homes and workplaces, emphasizing functional movement and injury prevention. Concurrently, I trained the other half of my time at Energia, as I began to get to know and truly embrace the clientele. It was the one job I just couldn’t leave.
Finally, the opportunity presented itself for me to become Spin certified.
From there, it seems as if the rest is history! In that time, I’ve completed my Master’s degree, purchased and and worked to re-brand the first studio, while recently opening our second location, “50/50 Fitness/Nutrition”. I can, without a doubt, say that none of it would have been possible without some truly amazing people who have been there to help and support me from day one. This new brand really embodies our shared vision for the future, and I’m extremely excited to be given the opportunity to present it to you.
So, with all that being said, welcome to the community!



Blog Post: Do You Believe in Second Chances?

Justin  Killeen’s Certifications:

  • ASCM Certified Personal Trainer
  • NSCA Certified Strength & Conditioning Specialist
  • TRX Suspension Training
  • Certified Spinning Instructor
  • Functional Movement Screen – Level 2 Certified
  • Exercise is Medicine – Level 1 Certified

Pat Monska

Pat has over 30 years of experience in the fitness industry and currently spends part of her week teaching a variety of classes at in Lenox. She is a group exercise instructor and personal trainer, passionate about teaching anyone and everyone, from those who are just beginning their fitness journey to seasoned athletes. She believes classes should be interesting, fun and challenging. Pat encourages everyone to work to their full potential and to have the confidence to push themselves out of their comfort zone and achieve their fitness goals. She believes cross training plays a very important role in staying healthy and injury free.

Pat has enjoyed participating in several charity rides in the area with her son, and recently completed a 72-mile ride in Northampton. In addition, she has completed several 5k races with her children which benefited local charities, as well.


  •  AFAA Personal Training
  • NETA Group Exercise
  • Certified Spinning®
  • TRX Suspension Training
  • TRX Rip Trainer
  • Kettlebell X
  • Zumba Certified
  • Vipr Personal trainer
  • Athletic and group certified
  • Indoor Row Certified
  • Silver Sneakers Certified
  • CPR/AED 

Jamie Cocco

Locally grown, Jamie is a hardworking, Dream Big person on a mission to help others reach their biggest goals. As a Certified Fitness Professional and Spin Instructor, he aims to bring opportunity, energy, enthusiasm, creativity, and focus together to build a great experience in the community. He has a wonderful girlfriend, two amazing children, and a rock pet his older son made him that sits on his desk at home. In his spare time he coaches kid’s soccer, exercises often, leads teams of young entrepreneurs, and runs workshops on communication, leadership, and team building.

Ryan Ambuter

Ryan has always been athletic and has always had a tough relationship with food. Throughout his life, these two truths have balanced each other, but as an adult, Ryan hit a point where he wasn’t feeling good in his body and wasn’t active anymore. In 2015, Ryan joined 50/50 as a client. Over the course of a year he got into the best shape of his adult life and found himself really invested in the community at 50/50. After meeting a series of health and fitness goals, Ryan got certified as spin instructor. For the first time in Ryan’s life, he actually felt some hope that he could form a positive relationship to exercise, food, and his body…and then Ryan got pregnant in the fall of 2016. That year was rough and after his baby was born in the spring Ryan basically found himself back at square one. Ryan is now back on the bike as a proud parent of an incredible little person, and is learning first hand about how challenging it can be to prioritize health and fitness with a young family. Food and fitness journeys are long and hard, and it’s important to Ryan that folks at 50/50 know he’s right there with them.

As an instructor, Ryan cares that his classes are accessible to all bodies and identities. He knows not everyone feels comfortable in a spin studio, but he believes people at all sizes and levels of fitness can be strong, can motivate, and can inspire. Ryan loves designing creative, butt-kicking workouts set to energizing, throwback playlists. He loves a heavy hill or a killer sprint. It is Ryan’s goal to lead intense, accessible rides that make you sweat, make you smile, and make you feel like all of your identities can have a home at 50/50.


  • Certified Spinning Instructor
  • CPR/First Aid certified

Lindsay Berry

Born in New York City, Lindsay moved to the Pioneer Valley from Seattle, WA, in 2000 with a BA in Art History and a master’s degree in acupuncture. Always an active person, Lindsay has enjoyed running, horseback riding, mountain climbing, hiking, yoga, cross-country skiing, and all kinds of fitness classes. She is also a very avid downhill skier.

She fell in love with Spinning in 2009 and has been at it ever since. She especially loves the way it improves her skiing! Lindsay is committed to making fitness a part of a busy life as a working mother of two young boys. A Licensed Acupuncturist since 1999, she believes sustainable fitness is a critical part of any holistic health goal, as well as to the maintenance of long term balance and illness prevention. And it should be fun, too!


  • Certified Spinning® Instructor

Jay McWilliams

Jay McWilliams has a passion for understanding how the body works on a functional level and helping people move better. Jay finds it incredibly rewarding to help people overcome limitations and meet their goals. As Director of Personal Training and Strength Programs, Jay enjoys working one on one with clients in personal training, leading the Targeted Training Programs and Outdoor Fit Camp, as well as coaching and training other personal trainers, and overseeing the assessment process. Jay uses a well-rounded training approach with an emphasis on proper posture and movement and corrective exercise. Jay truly enjoys being a life-long learner and is continually finding new ways to help meet the diverse needs of his clients.

Jay has a Bachelors Degree from the University of Arkansas and a Master of Science from George Williams College. In his free time he enjoys hiking, camping, and backpacking with his wife Rose, gardening, and playing with his puppy Felix.


  • ACSM Certified Personal Trainer
  • Certified Spinning Instructor
  • First Aid CPR/AED
  • ACSM Exercise Is Medicine Level 1
  • Certified Functional Strength Coach

Sarah Blackmore

Sarah has always lived and worked in the Pioneer Valley, where it is easy to develop a passion for a fit and healthy lifestyle. Her lifelong interest in fitness began with gymnastics and continued through high school where she ran track. As an adult, she continued to run, but explored other fitness programs. She was introduced to spinning and it wasn’t long before she was certified and instructing. To provide a fitness experience for her clients where she can motivate people through life changes and transitions while witnessing the growth and confidence they develop is one of the things she loves about instructing.

She is continually challenging herself and has received many awards for her performance at local races. She loves to push herself in and out of the gym; and loves that moment of accomplishment in what seemed impossible only a short time ago. To Sarah, the 50/50 Community has shown her a ton of support and encouragement through her own personal growth. Sarah passes that on to her clients in her classes providing progressions so that members see their own growth and strength as well. In addition to her 50/50 Instructor role, Sarah has been a hairstylist in Northampton for the past 13 years.



  • Certified Spinning® Instructor, CPR/AED

Brittany McDonald

Brittany is a recent graduate of Mount Holyoke College, an all-women’s college in South Hadley, Massachusetts. She graduated with a Bachelor’s degree in Environmental Studies with a concentration in Conservation and a Psychology minor. Her passion for the great outdoors began when she found a passion for soccer. She started when she was 9 years old and continued until her sophomore year of college when she reluctantly had to stop due to knee problems and finally surgery. She was on the Belchertown High School girls’ varsity soccer team for all four years of her high school career, two of which she was co-captain and a four-year varsity starter. She later was recruited by Mount Holyoke College and spent a year at Springfield College where she was co-captain of the JV team.

Throughout college, she grew a passion for fitness, health, and the importance of taking care of one’s body of which she considered changing her major for. She worked for a local gym in Belchertown during her college career. After graduating and moving to Granby, she found limitless potential and excitement at Energia fitness where she will be working as an Environmental representative to raise awareness of our green energy bike generators, as well as beginning a career path in small group fitness. She has been recently certified as a Spinning instructor and will be starting to teach classes soon!


  • Certified Spinning® Instructor