6 Industrial Road
Pequannock NJ 



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About Thunder Fitness



Thunder Fitness is more than a gym, we like to think of it more as a unique fitness experience. We are about getting better in all areas of your life.  We're also big on building relationships with our clients so that we understand the needs of each and every client.  We do not have contracts and yet we have clients we've been training since 2007. 

All of our programs from private to group training are all customizable to each person's needs and limitations.  We accomplish this with the relationships we build and "knowing" all of our clients. We know when to push, we know when they need to slow down... 

Your goals become TF's goals.  We all work together, even clients help each other out... We all give our advice on what's working, what's not working and are constantly looking to improve.   


We also want you to know that there is no quick fix - I want to make sure that you understand this so that we don't come off misleading.  The illusion of there being a final destination doesn't exist.  You don't just hit your goals and get to stop doing what you did to get there.  You have to continue putting the effort in and becoming the person it takes to achieve the goals you want.  


​So if you're ready to make a change and LIVE THE LIFE of focusing on becoming a better version of yourself and understand that there is no quick fix, this is your place.

We do deliver real results.

We have all types of programs that meet your needs & budget:  

- Large Group Training for light strength, conditioning and fat loss

- Small Group Training for Strength Training 

- Semi-Private Training for custom workouts in a group of 2-4 people

- Private PersonalTraining to work on specific needs



Jeremie Guarderas

TF Coach & Owner


My name is Jeremie Guarderas, Owner of Thunder Fitness

I am an ISSA Certified Personal Trainer, Certified USA Boxing Olympic Coach, Certified MMA Conditioning Coach, and a TFW Certified Coach and I have been taking clients/friends bodies to new levels since 2007.  

More importantly, I find the most interest in building relationships with our clients so that everyone actually enjoys the process on their road to results.

My approach is different from others in the fitness industry...


I think it's important to know that I do not have that "ALL BUSINESS" approach... So You should never feel intimidated to walk through our doors... 


I'm more about creating a positive environment and since our gym is far more than just a business relationship, it's important to me that you understand and contribute to the positivity.

Hope to meet you soon!

Jeremie Guarderas ISSA CPT

Austin Crist


My name is Austin Crist and I am a National Personal Training Institute certified personal trainer. I have been training clients of all ages for a number of years now getting them in the best shape of their lives. 


I discovered my love for personal training while I was playing sports such as football and baseball in high school. Being in the gym, helping my fellow teammates out, really gave me an enjoyment to help people out with their overall health. 


I don’t believe anyone should ever feel discouraged about training regardless of what physical traits they have because in the end, the journey is well worth it and you’ll feel like a new person. That’s what I try to bring to the table, not just bettering ones physical health, but their mental health too because that’s where it all starts. 


Hope to meet you all soon! 

Austin Crist NPTI CPT

Kristine Casali 



My name is Kristine Casali and I am an ISSA CPT.  I am self-employed in a family business and a mother of two.  So I know how hard it is to balance a healthy lifestyle and make time for yourself.  I had always led an active lifestyle growing up as a competitive figure skater.  However, with college, then starting a career and family,  taking time for myself took to the back burner.

In 2009 after moving around to a few gyms I met Jeremie and began group training and personal training.  After 8 years of hands on learning I decided it was time to share my passion for fitness with others.  In December of 2017 I became a Certified Personal Trainer.

Some of my proudest accomplishments since I began training at Thunder Fitness has been completing two NYC marathons and more than a dozen half marathons.  My love of running has motivated me to start and unofficial TF running group that meets several times a week for a few miles before class. 

My lifestyle change since joining TF is also one of my proudest accomplishments as well. 

My desire in becoming a CPT was to be able to use the knowledge and the years of experience to change the lives of others the way my life was changed.  I would love to add working with clients and achieving your goals as one of my accomplishments.

Hope to meet you soon!​

Kristine Casali ISSA CPT


Getting Here:

Newark Pompton Turnpike to Industrial Road

Our Address:

6 Industrial Road 

Pequannock, NJ 07440



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What was life like before starting with us at Thunder Fitness?

Before Thunder Fitness I always had a gym membership, but never would go.  I would start off strong, then quickly become bored with my routine, or just didn't see results.  So it wasn't long until I went back to old habits.


What obstacles did you overcome to join Thunder Fitness?

One of the obstacles I had to overcome was dedicating time to workout. I work 12 hour shifts, so setting an alarm on my days off to get up to train was torture. Now I'm up and ready to go! There is no better way to start my day!!     If I don't start my day at TF, it's just not a good day!


How has being a TF member affected your life?

Being @ TF is being surrounded by the most positive group of people I know! Jeremie, Aaron and Ilana are so supportive and encouraging it's makes me want to be a better version of my fitness self!! The group of members follow suit, the best cheerleaders you could ask for! Everyone is so happy for everyone else's success, and supportive and encouraging when you slip.


What specific results have you achieved from Thunder Fitness?

I joined TF in early summer... I was hooked immediately on the training sessions, but didn't really get serious about the nutrition aspect until Oct. Once I put the two together, I lost 12lbs in 8 weeks!! Maintained the loss throughout the holidays, and now 16 weeks in, I've lost 19 lbs!!!! Not sure about the inches, but since none of my clothes fit, I'm guessing theyre down alot, too!


If someone was on the fence for joining Thunder Fitness, what would you tell them?

When I first joined, I asked one of the members (Later found out it was Pam DeNardis) how long she had been coming, and that she was my inspiration! Everyone is getting better every day @ their own pace! You will not find a more supportive, positive, encouraging group of people anywhere!!! 24/7 emails, fb group, texts....someone is always there to keep you on track!


What is your favorite part of Thunder Fitness?

My favorite part of TF is the camaraderie! We are all busy with job and family obligations, but we all come together to work out, support and encourage each other! 


~ Carol ~

My fitness life before Thunder Fitness was non existent.  I did not have a fitness routine until the day in 2007 that I passed an advertisement for a Bootcamp.  Intrigued as to what this class would be all about I picked up the phone and called the number on the flyer. That one phone call changed my life forever, for the better.  I started off by telling Jeremie I could only come once a week on Friday’s (my day off).  That lasted about 2 weeks, and from then on I have been training group, semi private, and 1:1 with Jeremie, 5 days a week for the last 8 years.


There were many obstacles that I had to overcome in order to achieve this.  Having a family with 2 small kids, running a business and a household, finding the time for myself was not easy.  That is why Thunder Fitness was the perfect fit.  The 5:30 am class was the perfect time.  It was a challenge at first  to get into the new routine of going to sleep earlier and waking up earlier, but after a few weeks it became my new lifestyle. 


Being a member of TF has effected my life in the most positive way.  It has effected me both physically and mentally.  Physically I have lost inches, have become more defined and toned in my muscles and have changed my eating habits for the better.  Mentally I approach my day with a much more positive attitude and overall happier self.


There is a sense of community, friendships, support and motivation at TF.  This support system starts with Jeremie.  He greets us each morning with a smile, and a new exciting workout each day. He challenges you when you don’t feel like being challenged.  He pushes you when you don’t feel like being pushed.  He modifies the exercises if he sees you are struggling or can handle more.


If you are considering joining  TF, or you are already part of the TF family and are struggling to continue with the program, I highly recommend Jeremie and Thunder Fitness.  After training with Jeremie for 8 years, I still continue to learn and improve each day.   I promise if you put your trust in him and follow his program you will see results and will be so glad that you did.  That one phone call changed my life, it can change yours too.


~ Kristine  

I have met Jeremie when he started the outdoor bootcamp at Kinnelon High School.  I am so glad I did!  I have never felt stronger or healthier! Jeremie is passionate about fitness and it shows through the energy and enthusiasm he brings to every session.  His easy going, always smiling, friendly personality creates a relaxed, comfortable atmosphere.  He makes each workout challenging, creative and most importantly fun, which sets the perfect foundation for success and a new healthier lifestyle for his clients.  Jeremie is a gem whom I very much appreciate having in my life as my amazing trainer, coach and friend.

In addition, I started doing private 1:1 sessions with Andre in the summer 2016. I wanted to take my fitness to the next level and work primarily on my upper body. Andre's approach is individualized, thorough, consistent, and challenging but all while having a good time. Andre is a great motivator, always pushes me and encourages me to test my own limits. I see a progress with every single work out. I have never been athletic and never really worked out prior to TF and yet I am amazed at what I have accomplished and now I feel better and stronger and can do things I never imagined. My pull ups are getting better and better, my push ups feel stronger every time. I am love the results and keep moving forward! 

~ Larissa 

Client since 2007

I'm Fitter & Stronger at 42 than I was at 24!

I have worked out on and off for over 20 years trying different workouts and gyms and just couldn’t get the results or motivation I wanted. When I came across an ad on facebook for Thunder Fitness I thought I would try something different. I'll be honest when I first walked in the gym and didn’t see the traditional gym equipment/machines I thought how good can this be but figured i'll give it a try. Let me tell you it was the best thing I ever did! In 6 months of being there I am fitter and feeling stronger at 42 then I was at 24. The trainers not only put together kick ass workouts that target different muscles everyday but they also take pride in making sure your posture and workouts are done the right way to avoid injury. I’ve never gone to a gym religiously and truly enjoyed working out until now. Thanks to Jeremie and Austin for making it fun and giving that extra push just when you want to give up because that has given me the results and motivation I've always wanted!