Meet Our Team of Professionals
Certified trainers and instructors who know your name, know your goals, and are here to help you improve the quality of your life through exercise and community.
Personal Trainers
Sergio Muñoz
Fitness DirectorNASM Master Elite Personal Trainer and lifelong martial artist — national karate champion, FMS, TRX and corrective-exercise certified.
Catherine Walsh
Personal TrainerNASM certified with specializations in fitness nutrition and weight loss; TRX, sandbag and Synrgy360 instructor.
Lindsay Hiebert
Personal TrainerB.S. in Kinesiology, NASM CPT and Corrective Exercise Specialist — competitive powerlifter who blends strength training with yoga and pilates.
Andrew Fisher
Personal Trainer30+ years in health and fitness — ACE certified in personal training, medical exercise and health coaching, with a rehab background.
Kevin Kim
Personal TrainerB.S. in Kinesiology with a decade of experience across Olympic weightlifting, powerlifting, injury prevention and rehabilitation.
Kevin Mangini
Personal TrainerNASM certified trainer specializing in pre/post-rehabilitation programs, strength and cardio conditioning, and hypertrophy training.
Erica
Personal TrainerIFPA certified trainer and spin instructor with a Masters in Social Work — proof it's never too late to reinvent yourself.
Aron
HIIT, Cycling & BootcampAron joined the Mactivity team in the Fall of 2024. As a NASM-Certified Personal Trainer and Schwinn Cycling Instructor, Aron is passionate about creating group fitness spaces and 1-on-1 experiences where folks feel welcomed, challenged, and connected. Outside of HIIT, cycling, & Bootcamp, Aron works as a Mental Health therapist in the greater New Haven area specializing in relational work, religious trauma recovery, and LGBTQ+ identity formation.
Group Fitness Instructors
Sarah
Group Fitness & Cycling20+ years of teaching — AFAA certified, Les Mills BodyPump, Keiser/Schwinn cycle, Barre Above and Mat Pilates.
Vanessa
YogaNew Haven native with 20+ years of practice and 800+ training hours — teaches Hatha and Yin with mantra and breath work.
Erin
Strength & StepCertified Les Mills Body Pump and Body Attack instructor and former dancer teaching high-energy strength and step formats.
Heather
Yoga500-hour Yoga Alliance certified with 20+ years of experience — powerful vinyasas taught with breath awareness and mindfulness.
Pauli
Yoga20+ years of coaching and teaching — 500-hour RYT whose classes emphasize kindness, acceptance and compassion.
Liz
Indoor CyclingSpinning enthusiast teaching since 2005 — AFAA certified in BOSU, Pilates and indoor cycling, and a marathon runner.
Latoya
Strength, Barre & ZumbaLatoya Armstrong is the Mactivity Group Fitness Director with 30+ years of group fitness. AFAA- and ACSM-certified. Cardio, HIIT, Barre, Mat Pilates, and Zumba, delivered with energetic enthusiasm.
Andrea
YogaFresh Yoga certified with a strong emphasis on body-healthy practice and correct alignment — creative sequencing, joyful movement.
Mario
Cycling & TurfAAAI/ISMA Master Personal Trainer, wellness coach and Keiser indoor cycling instructor — mentor, motivator, and proud grandfather of 24.
Alexzander
Group FitnessNASM CPT specializing in women's fitness — accomplished marathon runner who once ran the 200-mile Yale-to-Harvard Ragnar.
Laura
Dance FitnessLaura Richling is an ACE-certified instructor with 30+ years of teaching many formats - coaching correct technique for movement that is effective, creative, and fun.
Lisa
Strength & CyclingTeaching since 2000 — step, kickboxing, bootcamp, strength, indoor cycling, Body Pump and Zumba.
Maxine
ZumbaMaxine Minalga is a licensed Zumba instructor who prioritizes high-energy, high-impact workouts in a welcoming and judgment-free space. Every level is encouraged, supported, and celebrated. Come as you are!
Alyssa
YogaAlyssa Materson is a certified yoga therapist and a 500hr registered yoga teacher. Her mission is to guide, share, and inspire others on their path in this life. She leads individuals into a state of self-empowerment, finding glimmers of peace in the chaos, and helps to provide resources to create resilience + regulate their nervous system into a state of balance. She strives to support individuals in experiencing meaningful changes in their lives on and off the mat. Alyssa teaches a wide age range, and she is mindful of making these practices accessible to all beings. Her style is invitational and supportive as she guides students in exploring multiple layers of being, also known as the koshas. Through yogic practices that cultivate embodiment, connection, & expansion, Alyssa strives to empower you on your wellness journey.
Isaac
YogaIsaac Mukwaya has been practicing and teaching yoga for the past 16 years. He is a certified Baptiste teacher as well as a Sivananda teacher and practitioner. Baptiste and power yoga give him the power and courage to show up, and Sivananda shows the calm and peaceful approach, connecting him to his intuition. Isaac believes that yoga shows us the universal truth that we are all one and we are all connected through breath, the life force. "My intention is to leave my students in their greatness, realizing their fullest potential on and off the mat. I welcome you", karibu sana.
Christine
Group FitnessChristine Ko fell in love with group fitness in college. She is currently certified by AFAA and has had certifications with AAAI/ISMA as well as Pilates training. She believes exercise as prevention is underemphasized and is passionate about teaching others effective ways to strengthen their bodies. Outside of fitness, Christine is a physician, host of The Girl Doc Survival Guide podcast, and author of two children’s books, Sound Switch Wonder and Love Language. She lives in New Haven with her husband and two kids.
Jennifer
ZumbaJennifer Thomas is a lifelong dancer and former collegiate dancer at Sacred Heart University with a passion for movement, music, and fitness. With years of experience as a dance teacher and choreographer, Jen discovered Zumba after college and quickly fell in love with its energy, fun, and sense of community. After having children, her love of fitness continued to grow, inspiring her to become a Zumba instructor and share that passion with others. As a licensed Zumba and Zumba Toning instructor, Jen brings her dance background, creativity, and high energy to every class, creating a fun and welcoming environment where everyone can feel confident, get stronger, and enjoy moving!
Melanie
Indoor CyclingMelanie Borsari is passionate about fitness and maintaining an active, balanced lifestyle. She enjoys staying strong, building endurance, and prioritizing movement as a key part of overall well‑being. She is a dedicated fitness enthusiast and endurance athlete who has completed 10 marathons. She has been an avid gym-goer since high school and has her AFAA Spinning certification, combining expertise with a passion for motivating others through movement. Melanie believes consistency, mindfulness, and self‑motivation are the foundations of long‑term health. She lives in Branford with her three rescue dogs — Angel, Blake & Sugar.
Dominique
YogaDominique O'Connell began her yoga and meditation journey 25 years ago, practicing Baptiste yoga in Boston and Brooklyn. After returning to her hometown of New Haven in 2008, she continued practicing Power Yoga while exploring a wider range of vinyasa styles. Over time, her practice evolved toward a deeper appreciation for subtle body awareness, slower and more intentional movement, breathwork, mindfulness, and yoga philosophy. An educator and avid runner and cyclist, Dominique has always been drawn to yoga’s grounding qualities and its ability to cultivate calm and steadiness in an often-busy life. Her vinyasa classes blend creative sequencing with movement and breath to build strength, flexibility, and body awareness while encouraging students to find a practice that works for them. Dominique also teaches candlelit classes that offer a slower, more grounding approach to movement. Through intentional pacing, longer holds, breath, and moments of stillness, these classes create space to turn inward, release tension, and reconnect with the body. Dominique completed her 200-hour yoga teacher training with 108 Monkeys in New Haven under the guidance of Peg Oliveira, Elizabeth Lowe, and Courtney Bauer. She also completed training in Mindfulness-Based Stress Reduction (MBSR) and has led mindfulness workshops in community and school settings. Whether through a strong vinyasa flow or a quieter candlelit practice, Dominique hopes that the steadiness and awareness cultivated on the mat carry into everyday life.
Michelle
Cycling, Pilates & StrengthMichelle Coppola has 20+ years of experience in the fitness industry, she brings a diverse background in Spinning, Pilates, Step, and Strength training. AFAA and Schwinn Cycling certified, she is also a 2nd-degree Black Belt in Tae Kwon Do and a former NPC competitor. Her encouraging, high-energy approach meets clients where they are, creating an empowering environment that safely inspires them to reach their personal goals.
Our Founders
Burch Valldejuli
Co-FounderGreater New Haven native with a 30+ year research career, most recently at the Yale School of Public Health — committed to individual and community health. "Imagine an inviting space to steward and enrich your physical well-being."
Pablo Perez
Co-FounderNew Haven resident, UConn business graduate and All-American rugby player with over a decade in the fitness industry. "My passion is to deliver an exceptional experience for our members."
Come Meet the Team
Your first two days are on us — and a trainer-led Starting Point Session is included with every new membership.
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