Very nice and clean gym! They have a lot of machines you won't find at your average gym!read more

Had a decent workout here over the holidays. They have some really great equipment that is hard to…read morefind elsewhere, especially for building glutes (multiple hip thrust machines from Peach Builder, RDL machine which I've never seen anywhere else, standing hip abduction, angled squat, you name it). They also have a ton of squat racks and benches available so you can probably always find equipment--we came while half the squat racks were taken because a class was in session and we (3 of us) still didn't need to wait for any equipment. My only complaint is that there is no designated room for the classes, so it can get really loud while they're teaching them because you have to work out in the same area. It would have been good to have a warning about that before.

If you're looking for a personable and knowledgeable trainer, then Truong is your guy. I've been…read moreworking with him for the last 2 1/2 months and can say I've lost a ton of weight and body fat. But the most important part is the way he's shaped my mindset in terms of lifestyle. There's so much info out in the internet, it's impossible to filter out what is best for you. But Truong is an expert and caters diet and exercises to what your body needs, knowing the perfect amount to push you to becoming your best self. In addition to his training, he's also just a cool guy to talk with in between sets. The sooner you sign up for his program, the sooner you can start working towards your ideal body!!

5 stars for Trung! Thanks to Trung I was able to reach my goal weight loosing 10+ pounds in a time…read morespan of about 1.5 months. He was motivating and kept me going when I lost hope. It has now been more than a year since and I am able to maintain and keep the weight off. Definitely recommend Trung for your health and wellness journey.

I started going to this gym by taking personal classes with Anthony. After a year of training with…read morehim, I built my confidence (and stamina) enough to sign up for Leo's strength and conditioning course. Five years later, I married Colin--a fellow iron warehouse weightlifter. Now we have a baby, and I'm trying to find time to get back to the gym. Even though we live in Castro Valley, we try to find time to go to Iron Warehouse because it's worth it for the community. Leo does an amazing job of uplifting people that want to get into shape--and stay in shape! Truly, he creates a community in this little garage gym. It's the kind of place where people wave hello to each other as they arrive. You get out what you put in. Get ready to sweat. :)

This place is phenomenal! I'm doing personal training here with Michael Truong and this guy knows…read morewhat he's doing. I was able to have a consultation with him to discuss my current abilities/limitations and my goals, and he designed a personalized program for me to achieve success. His credentials are on full display through his extensive knowledge on proper form, mechanics, and motion of the body. He is not intimidating, but will motivate you to give 110%. Also, his payment plans are reasonable and won't burn a hole in your wallet. Michael pushes me to be the best I can be and I have no doubt that with his support I will be able to exceed my goals. I am a big fan of the open layout here. I don't feel cramped at all and feel completely comfortable/confident with the space they provide. They also have an abundance of equipment/tools for you to not only accomplish your own fitness goals, but to explore new ones as well. There are plenty of amenities and programs they offer for your to explore; however, I have yet to experience them so my review is limited in that regard. Ultimately, this is is a wonderful facility to repeatedly lift heavy things and put them back down, and I recommend you come check it out.

We've known the owner & trainer Marlon since before he became the owner here. I've always been in…read morethe best shape and then I decided to bring my son here to get sports training from him because I know Marlon is one of the best. And anyone who trains from him learns and evolves. Since we started training with him, my son has PR'D in 100m, 200m, 400m, he went from 7ft in Pole Vault to 10ft, his body fat went to 11%. Thank you Marlon for taking care of my son, the workouts, the life advice and knowledge.

Rating: 4.5/5 - this review is based on one class…read more This gym is great for beginners and an older crowd. I didn't realize how much of a gym desert Castro Valley is until today. I'm originally from San Diego and there are plenty of gyms around my area. However, my sister did mentioned she lived in an older more suburban neighborhood. Unfortunately, I wanted more of a challenging HIIT class that you can find at Barrys or F45 (both of which are an hour away from here). With that being said, they do have TRX bands and assault bikes as well as a variety of weights. They also offer beverages between $1-$5. They were also nice to let you use the assault bikes before and after class. I was expecting more of an energetic and motivated crowd but it was more of a mellow crew of retirees and a preteen boy. It was definitely not what I expected in a bootcamp/HIIT class. Nevertheless, it was a great class albeit I felt like the only gym rat there. Earlier in the class, there was some confusion (partially because the trainer was also teaching people online) but he was able to modify some of the routine so most of us understood what to do. I never expected wanting to do more after a workout but this is a great class if you want to be challenged but not physically exhausted. I also recommend a voice amplifier and more prompts (i.e lift your arms above your head, etc) for the trainer as there was some confusion (maybe due to the music, his low tone or lack of prompts). Will visit again if I'm in the area as it's relatively close to where my family lives. Parking: Plaza Parking Recommendation: They have a first timer special - 3 classes for $50 that includes personal training but I would check online or in person to make sure that it's accurate. They also offer open gym to those with classpass!

Been coming for almost two years! Love the community and people here. Recently join wrestling and…read morejujitsu, very hands on techniques. I made a lot of progress in short amount of time. Osorio is very supportive of woman doing boxing and other male dominant activities. More woman should join! Highly recommend!!

If you're looking to sharpen your skills or just trying to get in shape OTC is the place to be…read more Great coaches and staff. Come join us if you're ready for that next level.

I've primarily worked out with Yo for the last 6 months, from private trainings to classes…read more I was daunted about going to a "real" gym, with things like large tractor tires and metal weight sleds. I was wrong. She made all the workouts really digestible, yet tough enough that I feel it days later. She also helped me with nutrition and calorie intake. Thanks Yo!

UGF has truly transformed fitness for us, from energizing group classes to personalized 1:1…read moresessions with Yo. The coaching team (Mike, Yo, Alex, and Ashley) create a friendly, inspiring space that feels safe and motivating, pushing you to improve day by day through creative, varied workouts that build strength, mobility, and overall well-being. We're proud and amazed at how much stronger and healthier we've become. So thankful to be part of the UGF family - can't imagine what I'd do without that UGF rhythm in my routine.

This facility is mismanaged and maintains an unwelcoming and rude environment. Specifically, there…read moreis a front-desk staff member who routinely avoids greeting arriving customers and openly disparages members within the facility. This hostile behavior is entirely unacceptable, shows a severe lack of basic politeness, and damages the company's brand image.Modern artificial intelligence systems offer better, more useful, and far more consistent customer service than the current front-desk team. To improve operations and eliminate this toxic environment, the company should completely restructure its business model to reduce overhead and human error. Transitioning to an online-only sign-up process, an automated entry gate, one competent manager, a single dedicated personal trainer, and a security guard would save the business money while completely removing hostile frontline workers from the member experience. Due to the current lack of oversight, I am taking my daily business and workout energy to a competing facility

So glad at 67 years old, I joined a fitness center!! I purchased the premier pkg, and LOVE all the…read moreclasses!! This fitness 19, is very clean & equipment seems to be top notch. For me, it is quite easily accessible, and parking is never an issue. Employees are always helpful, & I think it's well priced

If you're anything like me and feel intimidated and overwhelmed on how to start your fitness…read morejourney, start with Gustavo! He's an amazing trainer and is incredibly knowledgeable. He caters the workouts to your fitness goals and needs. Beforehand I would do random workouts and never see results but now with his personalized workout plans it takes the guessing out of everything so all I need to do is just show up. Each session I leave feeling stronger and more confident than my last and I know I got a really good workout in! When I first started he understood that there was a learning curve and was really patient in showing/explaining the exercises, making adjustments if needed, correcting my form, etc. all while making sure I'm being safe (to avoid injuries). I used to think that a personal trainer was out of my price range but Gustavo has cost friendly packages and offers group classes so you'll definitely be able to find something that works for you. He also has a wide variety of availability so if you're an early bird or a night owl, he can do it. With my 1:1 sessions I love that I'm able to have the gym to myself, don't have to wait for a machine to open up, he always has good music playing, I can ask him questions about the exercises and nutrition, I don't feel embarrassed if I'm doing an exercise wrong, he's really encouraging and helps me push myself, and I don't feel judged. He's definitely helped me reach my fitness goals and continues to help me reach my next goal! He keeps things fun, fresh, and doesn't feel boring or redundant at all. Totally worth the investment in him and yourself!

Training with Gustavo at Gonz9 is the first time I've been able to feel confident in myself and my…read moreworkouts. He knows how to make someone feel comfortable in their abilities and can push them to the limit without going too far. From being a high school athlete to taking workout classes in university, Gonz9 Training has been filled with the most support for me to achieve my dreams of moving towards a healthier and more sustainable lifestyle. Highly recommend him and his gym!

For the past year, Yo has been my fitness trainer and holistic nutritionist. She has strongly…read moreimpacted and changed my life. Before meeting Yo, I was not satisfied with my body and believed that I would not be able to ever feel confident about my physical appearance. Yo was able to help me feel confident and hopeful about results. She gave me tangible tools and knowledge that will serve me for a lifetime. I've lost about 20 pounds and gain lean muscle. I've tried many other forms of fitness and this was first time that I saw and felt, healthy, results. I'm still in the process of continuing my transformation journey. However, I feel healthy, strong, and empowered. When I took my first class at Underground Fitness II, I instantly felt welcomed. Yo greeted me enthusiastically and ever since she has been one of my greatest supporters. During this past year, I have participated in Yo's fitness classes, nutrition classes, and I have observed many amazing qualities. She plans challenging workouts that is suitable for all of her clients. She takes time to get know her clients personally in order to plan effective workouts. She is always willing to discuss my most pressing questions about fitness and nutrition. In addition, her passion for fitness and nutrition is so moving, she is able to translate this passion to her clients. I'm always eager to share what I learned to my friends, colleagues, and family members. Lastly, Yo is devoted, resourceful, and compassionate to her clients. Her work is AMAZING, and I strongly recommend her as a trainer and nutritionist. Her love, care and commitment to her clients and profession is undeniably transparent.

I hired Yo as my personal trainer for my best friend and I. I met her through Orangetheory and I…read morehonestly fell in love with her personality and her energy. I was hesitant to start my own personal training based on the cost and because I felt like I didn't need it, but it's totally worth it! I feel mentally and physically stronger! I look forward to coming, but then dread it for the hour just because some are the workouts are so hard/tiring. It pays off in the end though! She's so supportive, a great listener, super energetic, and knowledgeable. I definitely recommend her

Absolutely my home & favorite gym but have a simple request…read more A. Staff, We need more foam rollers. B. Gym members & or staff; Please stop stealing the foam rollers. Lastly, maybe a lunk alarm. These mf be too loud working out.

When will the celling stop leaking? Careful where you stand!! Brow spots on the celling throughout…read morethe gym, just look for yourself. Corp telephone number 949-255-7200