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Relentless MMA & Fitness

5 ★★★★★ 68 Google reviews · Kickboxing gym in Fairfax, Virginia

Kickboxing gym Beginners welcome Kids & teens Cardio kickboxing Private lessons Competition team Affiliated

Affiliated gym — reviews and the gym's own info suggest it belongs to a known kickboxing or boxing-fitness franchise or network (think 9Round, iLoveKickboxing, CKO, TITLE Boxing Club or Jabz). Franchise gyms run a consistent class format and are often a friendly, familiar place to start. If a specific brand matters to you, confirm it on the gym's own site.

Plan your first class

  • Beginner-friendly all fitness levels welcome, including total beginners — no experience needed, and you get in shape by training, not before
  • Cardio kickboxing classes high-energy cardio kickboxing on the bags and pads — a fun, sweaty workout built for fitness and weight loss, at your own pace
  • Kids & teen classes kids and teen kickboxing classes — built around confidence, focus, and fun
  • Private lessons one-on-one coaching available — a focused way to start or to work around a busy schedule; ask about availability and rates
  • Competition team a competition team for members who want to test themselves in the ring — amateur kickboxing, muay thai, or K-1
  • Today see hours ·
  • Website & schedule relentlessmmaandfitness.com — book classes and see the live schedule
  • Phone +1 540-999-8270

Hours

Monday 5:30 am–11 pm
Tuesday 5:30 am–11 pm
Wednesday 9 am–5 pm
Thursday 9 am–5 pm
Friday 5:30 am–11:30 pm
Saturday 5:30 am–10 pm
Sunday 6 am–8 pm

Hours shift for holidays and class-schedule changes — worth a quick check before a special trip.

The classes they run

Kickboxing classes on the schedule at Relentless MMA & Fitness, confirmed in members' own reviews and the gym's own info — not guessed from the sign out front.

🌱 Beginners 2 mentions

“Great teaching style and he can adjust it to all skill levels.”

All gyms that run beginners →

🏆 Competition Team

“If you are looking to learn self defense, compete, or stay fit David Carter will get you there.”

All gyms that run competition team →

🦵 Muay Thai 7 mentions

“Been going here for almost 1 year and I've gone from knowing nothing and out of shape to be in the best shape I've ever been and knowing the secrets of Muay Thai!”

All gyms that run muay thai →

🥊 Boxing 4 mentions

“I attend at least 3 MuayThai, MMA Boxing, Boxing and self defense classes every week.”

All gyms that run boxing →

👤 Private Lessons 3 mentions

“I schedule a personal training session with Coach David Carter weekly in Arlington, VA and drive to Relentless MMA in Chantilly, VA when able.”

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Kickboxing Bootcamp

“I also love the boot camp classes, even at 9AM on Saturdays!”

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🔥 Cardio Kickboxing

“I learn new techniques every class and continue to work on perfecting techniques from previous classes- all while getting a great workout.”

All gyms that run cardio kickboxing →

Other martial arts here

Kickboxing gyms are usually multi-discipline. Here's what else members mention training under the same roof at Relentless MMA & Fitness — mined from their reviews and the gym's own info.

🦵 Muay Thai 7 mentions

“Been going here for almost 1 year and I've gone from knowing nothing and out of shape to be in the best shape I've ever been and knowing the secrets of Muay Thai!”

Other gyms that also teach muay thai →

🥊 Boxing 4 mentions

“I attend at least 3 MuayThai, MMA Boxing, Boxing and self defense classes every week.”

Other gyms that also teach boxing →

🏟️ MMA 19 mentions

“Dave Carter at Relentless MMA is hands down ( I know coach keep my hands up ) the best coach I have had in my 20 year sports career; soccer, lacrosse.”

Other gyms that also teach mma →

🥋 Brazilian Jiu-Jitsu

“He’s deeply passionate about martial arts and highly skilled in multiple disciplines, including Muay Thai, Karate, Kali, and Jiu-Jitsu.”

Other gyms that also teach brazilian jiu-jitsu →

🥋 Karate

“He’s deeply passionate about martial arts and highly skilled in multiple disciplines, including Muay Thai, Karate, Kali, and Jiu-Jitsu.”

Other gyms that also teach karate →

🛡️ Self-Defense 5 mentions

“I am still amazed that after all these years he still has a wealth of new combat sport and self defense knowledge to share.”

Other gyms that also teach self-defense →

Disciplines are mined from reviews and the gym's own info — they show what members have trained, not a formal class guarantee. If you specifically want muay thai, boxing, or MMA alongside your kickboxing, confirm the current schedule with the gym.

What members say

The things reviewers bring up again and again across 68 Google reviews — in their own words.

🧑‍🏫 expert, motivating coaching 12 mentions

“Fantastic gym and fantastic coach. What makes David Carter a great coach is his love of MMA, in-depth knowledge and great coaching/communication skills.”

🌱 welcoming to beginners 4 mentions

“As soon as I walked in the door Dave was kind and welcoming and put my nerves at ease.”

🎉 fun, high-energy classes 2 mentions

“I learn new techniques every class and continue to work on perfecting techniques from previous classes- all while getting a great workout.”

💦 killer cardio workout 4 mentions

“Been going here for almost 1 year and I've gone from knowing nothing and out of shape to be in the best shape I've ever been and knowing the secrets of Muay Thai!”

🏆 active competition / fight team 3 mentions

“No matter what shape you are in, from getting started on your fitness journey to competition-grade martial arts, you need to go where the best training is.”

💵 good value / fair pricing 2 mentions

“There’s always some type of great deal going on for new people to try it out.”

From the reviews

Can't say enough good things about Relentless MMA & Fitness. Coach Dave is the best instructor I've ever had (and I've had A LOT). It took me 40 years to finally find a place and instructor who makes me actually want to come to class and smile while I'm there!

★★★★★ — Ali, Jul 2018

Where do I start. Dave Carter at Relentless MMA is hands down ( I know coach keep my hands up ) the best coach I have had in my 20 year sports career; soccer, lacrosse. I was a bit nervous going into the gym, not knowing what to expect.

★★★★★ — Zack, Sep 2018

I have always hated going to the gym to work out, but training Muay Thai at Relentless has been an wake up experience for me. I have no major intentions of fighting matches, but cutting weight and building some muscle tone ARE my goals. Learning to effectively defend myself form harm is just a big plus.

★★★★★ — Michael, Mar 2017

I find it hard to express in words how great this gym is. Coach Carter is very knowledgeable and explains new techniques in a ways that are easy to understand. His knowledge extends past the violence. He has helped me with diet plans and he has personally helped me rehab my knee after surgery.

★★★★★ — Dustin, Feb 2015

Excerpts from public Google reviews. Read all 68 reviews →

New to kickboxing? Start at Relentless MMA & Fitness

Relentless MMA & Fitness comes up as a beginner-friendly gym, going by their listing and members’ reviews. If you've never thrown a punch or a kick, that's exactly who a good beginners class is for. A few things worth knowing before your first week. First, you don't need to be fit or coordinated to start — you get in shape by training, not before it, and coaches scale every drill to you. Second, you won't be thrown into hard sparring — reputable gyms build the basics (stance, footwork, and punches and kicks on pads and bags) first, and any contact eases in gradually under a coach's control. Third, all fitness levels really are welcome — ask about a dedicated beginners or fundamentals class time so your first session is alongside others who are also starting out. Most gyms are happy to let you watch or try a class first, so reach out before you commit.

Check beginner classes on their site

Your first kickboxing class at Relentless MMA & Fitness

Nervous about walking into a kickboxing gym for the first time? Almost everyone is, and good coaches expect beginners to come through the door. Here's what to know. What to expect: a typical first class is a warm-up, then drilling the basics — stance, footwork, and punches and kicks on pads or a heavy bag — not hard sparring. Go at your own pace and rest whenever you need to; no one will bat an eye. What to wear: comfortable athletic clothes you can move and sweat in, and supportive trainers. What to bring: water, and hand wraps and gloves if you have them — many gyms lend loaner gloves for a first class, so it's worth asking when you call. As you keep training you'll add your own gloves and wraps (and shin guards once you start sparring). Sparring is optional and eases in gradually, once your basics are solid. Arrive 10–15 minutes early to sign a waiver and meet the coach. It gets easier fast — most people feel far more at home by their third class.

Kickboxing is a contact sport. Warm up, pace yourself, listen to your coaches, and if you have any injuries or health concerns, mention them before class and check with a doctor if you're unsure.

Where to find Relentless MMA & Fitness

3950 University Dr 103 103, Fairfax, VA22030

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Listing verified July 2026 from public business records and member reviews. Something out of date? Report a correction. Own this gym? Claim your listing — it's free.