I started training with Jeff because I wanted to become more confident with weightlifting while managing recurring injuries to my lower back, knee, wrists, and neck. As someone who is hypermobile, I needed a trainer who understood how to build strength safely and effectively without increasing my risk of injury. At the time, I was hesitant to lift heavy weights because I had experienced injuries working with other trainers, but I knew I wanted to build functional strength and mobility--including being able to safely lift and carry my 45 pound dog. Over the past five years, Jeff has completely transformed my relationship with strength training. From the beginning, he created a personalized program that helped me build consistency, confidence, and proper lifting skills. What sets Jeff apart is his meticulous attention to detail and commitment to proper form. He took the time to understand my injury history, hypermobility, and individual goals, and adapted my workouts accordingly so I could make steady progress while staying safe. Jeff is incredibly knowledgeable, kind, and optimistic. He listens carefully, meets you where you are, and provides just the right amount of encouragement to help you grow. Throughout my pregnancy and postpartum recovery, he thoughtfully modified my program to support my changing needs while helping me maintain and rebuild strength safely. Today, I am stronger and more confident than I ever thought possible. I can now lift my dog from the ground, and I have developed a level of confidence with strength training that I never thought I would achieve. If you're looking for a highly personalized training program and are willing to show up and put in the work consistently, I highly recommend training with Jeff. His expertise, attention to detail, and thoughtful coaching have made a lasting impact on my health, strength, and confidence. read more

I have been working with Jeff for years now and he has completely transformed the way I approach my fitness and my goals. I had already considered myself reasonably experienced in the gym before working with Jeff, but Jeff was able to show me so, so much more and bring me to the next level. He took the time to pay close attention to and correct my form, emphasized the importance of mobility, and provided structure to my routine. The best part about working with Jeff over the years has been how personally Jeff has worked with me on my changing goals. He always makes sure to work on specialized programming with you and check in to see how it's going. Can't recommend Jeff enough! read more

I've been working with Jeff for the past three years, and he's played a huge role in helping me build a consistent, sustainable fitness routine. What initially stood out to me was Jeff's philosophy around training. Instead of focusing solely on aesthetics or isolated muscle groups, he prioritizes mobility, flexibility, and functional full-body strength. The goal isn't just to get stronger in the gym--it's to move better, feel better, and support long-term health. He is also incredibly approachable and supportive. Whether you're completely new to weight training or have years of experience, he creates an environment where you can learn, ask questions, and build confidence without feeling intimidated. Another major benefit of working with Jeff is the level of personalization and accountability he provides. Every session is tailored to how you're feeling that day, both physically and mentally. He pays attention, communicates well, and adjusts workouts based on your needs rather than forcing you through a one-size-fits-all program. He knows when to encourage you, when to challenge you, and when to scale things back, which has made it easy to stay consistent and keep showing up year after year. If you're looking for a trainer who genuinely cares about your progress and takes a thoughtful, individualized approach to fitness, I highly recommend Jeff. read more

I've worked with Jeff for over a year, and what stands out isn't just his knowledge of strength training and mobility--it's the consistency and care he brings to every session. Plenty of trainers can put together a workout. Jeff takes the time to understand how your body moves, where your limitations are, and what will help you stay strong and healthy for the long term. As someone with a demanding schedule, I've always appreciated how he adapts training to real life rather than expecting life to revolve around the gym. The biggest difference he's made isn't what happens during our sessions. It's how much better I move, feel, and function outside of them. Everyday activities feel easier, nagging aches have improved, and I have far more confidence in what my body can do today than I did when I started. Watching him build Sun Functional Movement has been exciting because it reflects exactly who he is: thoughtful, professional, deeply knowledgeable, and genuinely invested in helping people succeed. If you're looking for someone who cares about your long-term health and not just short-term results, Jeff is exceptional! read more

I've been working with Jeff for over a year, and one of the things that stands out most is how thoughtful and knowledgeable he is as a trainer. He takes the time to understand your goals, explains the purpose behind the exercises, and always makes sure you're training in a way that makes sense for your body and fitness level. What I appreciate most is that Jeff genuinely cares about his clients and their long-term success. He's patient, encouraging, and pays close attention to details that many trainers might overlook. Every session feels personalized rather than following a generic workout plan. He's also professional, reliable, and easy to work with, which makes it much easier to stay consistent. If you're looking for a trainer who is experienced, attentive, and truly invested in helping his clients, I'd highly recommend Jeff. read more

I've been getting workout programming from Jeff for the past two years, and it's been a great experience. What I like most is that every workout is tailored to my needs, body condition, fitness level, and personal preferences. If there's a certain area I want to focus on, he adjusts the program accordingly. When I was dealing with ankle pain and swelling, he quickly modified my workouts so I could keep training without making things worse. When I wanted to improve my balance, he added exercises specifically for that as well. Jeff is very detail-oriented and communicates well. He regularly checks in, makes adjustments when needed, and genuinely pays attention to how things are going. For me, the biggest benefit has been consistency. Having a personalized program takes the guesswork out of working out and keeps me accountable. It feels like having a personal trainer guiding my workouts, but with the flexibility to train on my own schedule. I highly recommend Jeff to anyone looking for a customized workout program that adapts to their goals and needs. read more

I've been training with Jeff for 3 years, and the transformation has been nothing short of incredible. When I first started, I had no idea how to properly lift weights -- now I'm deadlifting over 250 lbs. That progress speaks for itself. What sets Jeff apart isn't just his knowledge -- it's how genuinely passionate he is about what he does. He takes the time to understand your goals and builds a program around YOU, not a generic template. He knows exactly when to push you harder and when to dial it back, which has made all the difference in my strength and mobility journey. Beyond the physical gains, I feel more energetic and confident in ways I didn't expect. He's not just an amazing trainer -- he's an amazing human being. Hands down the best trainer I've ever worked with. If you're serious about your fitness, look no further. read more

I've worked with Jeffrey for almost two years and he's always been reliable, knowledgeable, and easy to work with. I really like that he always demonstrates each step in a clear and hands on way and he also correct my form if I am doing incorrectly! Definitely recommend if you are looking for a professional personal trainer read more

I've been training with Jeff for several years now, and highly recommend working with him for anyone regardless of their fitness level or goals. I've always considered myself an athletic person. Growing up I've played several sports, and have always been pretty active. After having knee surgery for a snowboard injury, I found it hard to get back to the same level of fitness that I had pre-injury. I found Jeff through a mutual friend and reached out. I was optimistic about working with Jeff after our first meeting where he helped me define some goals from our training, and laid out a plan so I could understand how we would work towards those goals. After training with him for several years, I have made huge gains in mobility, strength, and have reached higher levels in my sports prior to my injury. Jeff is super attentive during our sessions and always does a great job at breaking down exercises, explaining why we are doing them, and choosing weights / modifications that are optimal for me. I highly recommend working with Jeff no matter what your fitness goals are--from developing a regular workout routine and cadence, to building a better physique and fitness levels, or improving at your sport. I'm confident that Jeff has the skillset to help you achieve whatever you want if you're willing to put in the work. read more

I recommend Jeff to anyone, 100%! I've worked with him for 2+ years now. During our sessions together, he knows how to challenge me just enough and is incredibly patient and encouraging. He pays close attention to my form during each exercise and corrects when needed, prioritizing proper technique over the amount of weight being lifted. He assigns customized workouts for me to do at home, and has videos (which are short and concise) demonstrating each exercise clearly. Through Jeff's training, I have been able to gain more mobility and lift heavier, and my sciatica is nonexistent these days (even with having a desk job). Jeff is a positive, friendly, and reliable individual who truly cares about his clients -- you won't regret working with him! read more

Ive been training with Jeff for 4 years now and have high praises for the man. Regardless of what your fitness goals are, whether muscle building or functional mobility or athletic peformance, Jeff can support you with customized workouts and weekly plans to help you achieve your goals. He's helped me greatly in living a healthier life and would recommend him to anyone looking to do the same. read more

I can't say enough good things about training with Jeff. He creates such a positive, encouraging space -- no guilt, just a great workout. What really stands out is his deep understanding of body mechanics. I came in with some back pain, and instead of pushing through it, he focused on mobility work that actually helped relieve the discomfort. Every workout blends strength training with movements that feel good and support long-term health. Ive worked with a few different trainers and Jeff by far has been the best one read more

I've been training with Jeff for almost two years now, and it's been a blast! Since my goals are more focused on power lifting and hypertrophy, our weekly sessions typically consist of a few sets of mobility exercises, followed by the workout for the main muscle group (for example, some variation of bench press for chest day, or deadlift for back day), and finally a couple of cool down exercises. Besides that, I also paid to subscribe for him to program my daily workouts. Jeff is an extremely personable and professional trainer. As a matter of fact, going to a session is like working out with a friend who is highly knowledgable about weight lifting, and laser-focused on helping me meet my goals. He also has a strong network of people that he has referred me to, if the need arises. I had been working out for the last 10+ years before I met Jeff, so I was at first hesitant that paying for a professional would make a difference. However, over the course of the first year with him, not only was I introduced to a wide variety of exercises, but Jeff was able to correct my form for my major exercises, and I've been able to set personal records in all three of these exercises since then! Roughly: Bench: 185 - 225 Deadlift: 185 - 335 Squat: 225 - 265 Since I also signed up for Jeff's daily workout plan, it is clear that Jeff's work ethic extends beyond our sessions. Jeff is very responsive when asked any clarification questions about the workouts he assigns on a daily basis, as well as any concerns that are brought up. To boot, Silicon Valley Athletics gym will sometimes host some fun athletic events and barbecues to stay fit and meet new people. Overall, I would highly recommend Jeff as a trainer! I would say the only caveat is that the waiting list may be long! read more

I am a professional badminton player and have been training with Jeff for the past year! He is far and beyond the best trainer I have ever worked with, after going through many different gyms and trainers in the past few years. He is extremely dedicated, designing sport specific workouts every single day to help me improve my physical strength and have it translate to what I do on the court. He also creates custom workouts for days I don't come in to train with him for me to do on my own, as well as workouts when I travel as well and have limited equipment! Jeff also knows the human body extremely well, helping to perfect my form when doing exercises or on the court, improving my mind-muscle connection, and knowing exactly which muscles (that I never ever knew about) that I should train to get the results that I want! This knowledge of the human body also comes in handy for rehabbing injuries as well (that I get too often), as he is always able to adjust the workouts to accommodate and treat all my different injuries. Jeff is the best trainer! read more

I never write reviews, but I've been coming here for a while now (3-4 years or so). It has been worth every penny. Jeff is super knowledgeable and friendly. Any goals you have in mind, he will give you a clear and cut plan on how to get there and provided you follow it, you will see the results you're after. You really can't go wrong working with Jeff. If you're on the fence I would highly encourage you to reach out and get yourself started, you won't regret it. read more

My daughter has been playing badminton for several years, and her coach recommended Jeff to help improve her power and explosiveness. Jeff is very friendly and professional. He started by testing all of my daughter's range of motion and then designed specific training programs tailored to her needs for game improvement. The results have been amazing! I noticed a significant improvement in her power within a couple of months, which directly benefited her performance in badminton tournaments. Her results have continuously improved thanks to Jeff's training. We have been training with Jeff weekly for over two years. It's important to complete his daily training homework to see quick results. Highly recommend! read more

I have worked with Jeffery for about a year now. The corporate gyms seem to have set the standards for industry. As a result the field has been watered down with trainers without proper education, always on their phones, lack of follow through, and no real drive outside of their paycheck. It seems harsh, but it's become the unfortunate reality today. Jefferey stands among the few with the proper education, doesn't carry a cell phone, outstanding follow through, and a drive to help people that shines. The attention to detail and passion he has for what he does is few and far between. I consider Jeffery a complete trainer. He has the passion, the knowledge, the follow through, and the professionalism needed to help others. A true standout among many. I would highly recommend Jeffery to those who are serious about reaching their goals. It's hard to find a good trainer and I can say with confidence he won't disappoint. read more

For a bit of background, I am a software engineer in my mid-20s who considered myself relatively active prior to COVID. I played club sports in college and after graduation, continued to exercise multiple times a week, usually by taking 2 or 3 cross-fit classes offered by my company and also playing my sport on the weekends. However once the pandemic kicked in, I found myself trying a variety of routines hoping to stay in shape (running, following videos, virtual classes offered by my company, and even ringfit adventure on the switch haha!) I found these routines mundane, repetitive, and deficient since they didn't really address my goals. I've been training with Jeff for the last 5 months now and boy can I say I've been impressed. Because of the pandemic, I opted to take remote classes with him (twice a week for an hour each). I'll admit I was a bit skeptical at first, but he was able to craft a routine for me that worked very well. From my time with him, I find the training more engaging than many of the classes I've taken before because it's customized to my specific body needs. For example, because I play a racket sport, my left and right sides are imbalanced in different parts of the body. Or since I work a desk job, I have really tight hip flexors. Jeff does a great job of consolidating these quirks and customizing a plan that tackles them head on. Plus, the steady stream of new variations/exercises keeps things interesting and working with him just keeps you much more accountable. My starting goals: Be more functionally fit for my sport (which I currently can't play due to the pandemic) and get my body more "beach-ready" for the summer months... and when I go somewhere tropical after this pandemic. Hawaii anyone? Results: In 5 short months, I've lost 15 lbs by adhering to his nutrition guidelines, gained muscle, and noticed more flexibility and mobility in my body. My friends and family have made remarks about the difference. Obviously you need to stick to the plan for results, but you're cheating yourself if you don't. I think he provides more than enough guide rails for you to be successful. Jeff is extremely personable and does a great job keeping you engaged during our 1:1 zoom sessions. I usually do them in my living room, but in 1 hour we usually have enough time to do a handful of exercises and I continue to be amazed how many variations he has on some of the exercises. Throughout our sessions, he is very attentive, not distracted, and is very patient while providing tons of informative commentary about the impact of each of the exercises. In addition, he provides nutritional guidelines (basic macro targets + caloric needs, adjusted periodically) and a comprehensive spreadsheet with a plan for daily homework/exercises to do at home. Obviously the frequency/intensity of these workouts are adjusted per person, but I opted for 3 at-home workouts a week (1 hour each) + 2 mobility days (stretches, etc) in addition to our bi-weekly zoom sessions. Each week, he punctually updates the spreadsheets with new adjustments to our at-home workouts in addition to throwing in some of the new exercises we learned for the week. If I have any questions about the workouts, I usually just send him a quick text for a quick response (rejoice, he uses iMessage!) For at-home equipment, I happened to have some old adjustable dumbbells/barbells (not a ton of weight) lying around at home and ended up buying a few hip bands/stackable bands/balance pads per his recommendation. Because he knows so many exercises, I don't think equipment should be a limitation here for the average person. He'll be able to come up with a routine that's effective even if you don't have the weights. Overall I'm giving him an effusive 5/5 and can't recommend him more!! Great guy, great trainer, and working with him made me realize how deficient my previous workouts were in terms of targeting the right muscle groups and achieving my goals. read more

I would like to echo all of the praise of Jeff's previous reviews- it truly is warranted. If you're waiting for a sign- this is it: train with Jeff, and you won't regret it! Still a little skeptical? I respect that. So, what in particular makes him stand out from other fitness trainers? I served in the military for 6 years and got the chance to work out with some very fit people, and I have to say Jeff's approach to physical fitness is the best I've seen. His workouts (which are customized to your specific goals) are not designed to assuage your ego. Instead, they uncover weaknesses and muscle imbalances that you weren't even aware you had, and they fix the way you move your body in workouts and in everyday life. If you spend at least a few hours in a chair per day (don't we all), Jeff's workouts will help undo years of damage caused by poor posture and atrophied stabilizing muscles (i'm looking at you, back and neck pain). After a combat deployment, countless training events, and stubbornly refusing to stretch after hard workouts, there aren't a lot of joints in my body that don't crack when I stand up. After just a couple of months working out with Jeff, I'm more functionally mobile than ever, more so than I was even in high school. I confidently recommend Jeff as a personal trainer because he's humble, incredibly knowledgeable, and very dedicated to your success. read more

Jeffrey is a legit fitness trainer that truly cares about your overall well being and not just looking to make you gain muscle. I've been training under Jeffrey for 7 months and I've learned how important it is for your body to maintain a high level of mobility. I've had a lot of issues with lower back pain, hip pain, and shoulder pain. Jeffrey has taken his time to create a workout plan every week specifically for me to help relieve a lot of these issues that I can never fix through a chiropractor or even a physical therapist. His knowledge about the body and more importantly your body exceeds my expectations. When I had trouble with my hip, I would have issues from simply getting out of a chair. Jeffrey created a video of stretches for me so I could easily follow along and stretch with him....and WALLAH my hip pain went away in a week and it was as if it was never there. Regardless of whatever your fitness goals are, Jeffrey will help you in all sorts of ways. I HIGHLY recommend considering getting a consultation with him to see how he can help you. read more

Sun Functional Movement - Stretching video he made for me - Trainers Near Me - San Jose, California

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For some background: Before working with Jeffrey, I would consider myself a complete beginner when it comes to working out. I always tried to find various ways to stay active, but it was always difficult to narrow down a routine that fit my needs, address my concerns and goals, and one that also kept me interested and motivated without the monotony. I never considered a trainer before, but I felt like some additional help would guide me down the right path, and I am so glad Jeffrey is the one that is supporting me through my fitness journey! I've been training with Jeffrey for close to a year now and from the start, his professionalism and passion completely shined through, even during our initial consultation. Due to the pandemic, I was very nervous about getting back into the gym and working out again, but Jeffrey made me feel completely comfortable and reassured. The initial consultation was extremely thorough, and Jeffrey made sure to ask a lot of questions regarding the types of concerns I have (I have existing hip mobility issues and knee issues) and my eventual fitness goals (overall increasing strength and tone). He assessed me on a series of workouts and found issues that I didn't even know I had! From there, he quickly developed a unique routine, both in the gym with him and at home, that is tailored specifically for my needs. What I enjoy the most about working with Jeffrey is that every workout with him is completely different, which allows me to stay interested and motivated. He also pays attention to my existing discomforts and is flexible and knowledgeable enough to quickly modify a specific workout, without having to remove it from the entire routine itself so I am still able to get through our planned workouts for the day. It's clear to see Jeffrey's dedication to his clients, he is never standing around on his phone (Common complaints I've heard from friends with trainers and things I've noticed in other gyms) and always makes sure to give 100% of his attention to you to ensure you get to where you need to be. Whenever I've ever had questions about work-outs, Jeffrey makes an effort to answer all of them to the fullest, and in the off-chance he isn't sure, he will always follow up with me our next session to give me an explanation. Even when he isn't in the gym with you, he's working for you and taking your needs into total consideration. I feel that my fitness journey has improved so much since starting with Jeffrey and I'm so excited to see where I get with him in the following years! I can't recommend someone more dedicated and passionate enough to see you reach your fitness goals than Jeffrey. read more

Jeff is such an amazing individual to work with and has taken me to great lengths as an athlete. He's always filled with positive spirits and guides you towards achieving your goals. I've had an amazing experience working under his wing and I have improved tremendously in my sport and physically as well. He is definitely someone you want to work with towards your goals. read more

Around the start of summer I had a goal of cutting some body fat and getting more lean, but I wasn't exactly sure where to start. Before I started working out with Jeff I thought my workouts were effective and helpful, but within the first week of my training Jeff showed me how I was using improper form for several exercises and how it could potentially lead to injury. He also had me do new exercises that focus more on mobility and stability rather than pure strength. Also, it's without a doubt that Jeff invests so much time into each client and their fitness goals. During sessions he's constantly focused on you and is always critiquing to help you reach your full potential. He's one of the most reliable and passionate trainers I've met and I highly recommend him to anyone regardless of training experience!! :)) read more

Due to the pandemic I had really struggled with fitness and maintenance which led to a lot of consistent pain in my back/legs. Desperate for help I reached out to Jeff and after an assessment and going over my fitness needs, he had devised a complete workout plan/schedule that was specifically catered to reach my goals. Jeff goes above and beyond to provide a professional and meaningful workout experience and I am so impressed on how much he gives into each session. From letting him know how I my body is feeling or improvements I am making, he will make adjustments to our workout plans and he clearly explains and demos the exercises while giving great feedback to get the most out each set. His feedback has really helped me the most and his ability to explain the why of each exercise and what muscles we are targeting helps me focus more on getting the most from each session. I can say that after a year and a half of being his client it has been such a positive experience for my health and I have learned so much about exercising/stretching that I feel more confident in maintaining my strength. Appreciate his help through my fitness journey and highly recommend to any level for a professional and safe space work out. read more

I started training here after a friend referred me so I had no experience in private trainers, but I can definitely say that compared to other PTs I've seen, Jeff is definitely the most devoted and meticulous trainer there is. He gives you a detailed plan with video explanations for you to follow every day, and during the sessions, Jeff will always seek to improve your form. On top of his exceptional training, Jeff is also a very social guy, me and him often have funny conversations about my friend and his fellow client, often competing with each other to see who is stronger. Additionally, if you are an athlete, Jeff can help guide you and target specific muscle groups to enhance your gameplay. Personally, as a badminton player I've felt this improvement through an increase in my stablity and power. All in all, in the 4 month I've spent with Jeff, each and every training session has felt impactful, and I will be forever grateful for the basics he has taught me. read more

I've been training with Jeff for a few months now (started end of 2020) and I can definitely say he knows what he's doing. While he knows everyone wants to bulk up and gain the flashy muscles, he puts just as much importance if not more in training your endurance and mobility. Since highschool I've had a ton of issues with my shoulders, both having been subluxated (partially dislocated) multiple times over the years, and my left shoulder being fully dislocated in early 2020. Jeff took the time to understand my pain points and develop a training plan that focuses on building mobility and strength in my rotator cuff. I've been to the doctors and to chiropractors, and the best has only ever been some temporary loss of the pain but it would always come back. With Jeff the pain has been going away for significantly longer and he's helping to fix the problem for good while still maintaining a full workout routine. My posture has improved, my shoulders line up straightly with my spine, and genuinely feels stronger. Now when I play spikeball or tennis, I don't need to wear a shoulder brace afterwards. I can be active and play sports without having to suffer later. At the gym or in a session with Jeff, I can lift heavier weights not only because my shoulder strength has improved but because he's helped me perfect even the smallest details of my form. During one session, he was even able to figure out that I have been walking wrong! Whatever your fitness goals are, Jeffrey Sun will know the best way to get you there. read more

I worked with Jeffery for more than half year. I have several years self-training. Instead of directly doing weight trainings he at first learned about my fitness goals, did many measures and designed detailed training schedule for me. He always start with some warm-up exercises to avoid any injuries. During the training, he explains every move clearly and introduces how are the muscles working together. During the training, He found many subtle physical issues that I never noticed. And he also designed useful and effective daily workout routines for me. Other than that, he also recored many demo videos which were also super useful for at-home trainings. I sprained my ankle while playing basketball and he also designed ankle recovery routines for me. After training with him I gained more muscle and core control, and I'm more confident to do weight trainings. I would like to recommend Jeffery if you are looking for personal trainers, he won't let you down! read more