As a certified personal trainer and intermediate lifter, I’ve always loved strength training. But after a summer of travel and unstructured workouts, my routine needed a reset. By September, I was ready to get serious about building muscle again but wasn’t prepared to jump straight into heavy lifting. That’s when I considered giving blood flow restriction (BFR) training a shot—a technique that involves applying pressure to specific limbs to stimulate bigger gains using lighter weights (or even just your body weight). It’s a method I’d always been curious about, but I wasn’t sure if it was right for me.
Historically, BFR training has been primarily used in clinical and physical therapy settings, allowing professionals to help patients build strength with light weights when heavy lifting wasn’t possible (due to injury or conditions like osteoporosis). But with the recent launch of portable, easy-to-use smart cuffs such as the SmartCuffs 4.0 and SAGA Fitness BFR cuffs, which automatically set the perfect level of blood flow restriction for each wearer, BFR training is more accessible to the everyday exerciser than ever before.
While both brands offer cuffs with automatic pressure calibration for precise, personalized use, the SmartCuffs 4.0 calibrates in just 10 seconds—quicker than SAGA’s 30-second process. SmartCuffs also offer more training modes (continuous, intermittent, and resting BFR—more on this in a sec) and multiple cuff size options for a better fit, compared to SAGA’s one-size-fits-all cuffs. So, I decided to give BFR a try using the SmartCuffs 4.0.
Meet the experts: Alexander Rothstein, CSCS, ACSM-EP, is an exercise physiologist and instructor for the Exercise Science program at New York Institute of Technology. Ed Le Cara PhD, DC, ATC, CSCS, is a strength and conditioning coach, chiropractor, and director of education for Smart Tools.
Blood flow restriction training works by creating metabolic stress in your muscles.
BFR training restricts blood flow to the muscles by using specially designed cuffs that you wear around your limbs; on the upper body, they wrap around the mid biceps/triceps, and on the lower body, they go around the mid-thigh, hugging the quads and hamstrings.
This creates metabolic stress within the muscle, simulating the effects of heavier lifting without requiring heavy weights, says Alexander Rothstein, CSCS, ACSM-EP, an exercise physiologist and exercise science educator.
Smart Tools SmartCuffs 4.0 (One Pair)
Metabolic stress occurs when muscles are deprived of oxygen during exercise, creating an environment that triggers a chain of reactions in the body to build muscle, says Rothstein. It’s one of three ways muscles adapt to training, alongside mechanical loading (lifting heavy) and muscle damage (think: soreness after a workout), he says. “BFR allows you to restrict blood flow and oxygen, promoting metabolic stress without having to lift as heavy, and you still get the same stimulus of muscle growth and endurance benefits.” This is especially valuable for those recovering from injuries, lacking access to heavy equipment, or looking for more efficient training options.
With consistent BFR use (two to three times per week), you can see increases in muscle mass and strength within three weeks with relatively low-intensity resistance training and short rest intervals between sets (about 30 seconds), according to a review published in the Journal of Strength and Conditioning Research—much faster than progressive overload strength training without BFR, which may take eight to 12 weeks to show similar results.
I used the Smart Tools BFR cuffs—and incorporating them into my workouts was easier than I thought.
My previous training involved functional movements and progressive overload—sans gadgets. But the SmartCuffs 4.0 were surprisingly easy to use, even for someone like me who isn’t exactly tech-savvy.
After unboxing the cuffs—which come in a carrying case with a USB-C charger and charging cord that allows you to charge two cuffs at once—I quickly charged them (which took less than 30 minutes) and connected them to the SmartCuffs app via Bluetooth. Positioning the cuffs on my body was simple: I wrapped them securely around my arms (mid-bicep) or legs (mid-thigh) using the Velcro straps.
Talene doing a set of biceps curls using the SmartCuffs 4.0 upper body cuffs and 10-pound dumbbells.
From there, the app guided me through “limb occlusion pressure calibration”—which was a 10-second process that determined the precise amount of pressure needed to optimally restrict blood flow to my muscles based on my unique limb circumference and blood pressure measurements. “Most modern cuffs determine occlusion pressure for you, taking out all the guesswork,” says Rothstein.
Then it was time to get started. I selected continuous BFR mode, which inflates the cuffs during both working sets and rest breaks, fatiguing muscles at a higher rate. Even after a lifting hiatus, I still consider myself a high-level exerciser, so I chose the continuous mode since it offers more of a challenge than the other two modes (intermittent BFR mode inflates the cuffs only during each working set and resting BFR mode inflates the cuffs during only each resting period).
Here’s what it felt like to wear the cuffs during a workout.
For five weeks, I incorporated the cuffs into the workouts from the Women’s Health 30-Day Fitness Challenge. I used the upper- and lower-body cuffs (each pair is purchased separately) twice a week each, slightly adjusting the order of exercises in the full-body workouts to group upper- and lower-body moves together, minimizing the need to switch between cuffs mid-session (since the app only connects to two cuffs at a time).
Each session took about 30 minutes—shorter than my usual training—and included moves like pushups, plank variations, rows, triceps dips, biceps curls, overhead presses, chest presses, squats, deadlifts, hamstring curls, and glute bridges. For upper-body workouts, I started with two eight-pound weights. For lower-body exercises, I started with two 15-pound weights. To maximize results, I followed a progressive overload approach, increasing weights by about 5 percent weekly.
Talene doing a set of squats wearing the upper and lower body SmartCuffs 4.0. (Only the lower body cuffs were inflated during this move.)
Current research on BFR training recommends starting slow, using light weights for the first two weeks to adjust to the cuffs. “It takes about two weeks to get used to the feeling of using BFR cuffs,” says Ed Le Cara, PhD, CSCS, a strength and conditioning coach, athletic trainer, chiropractor, and director of education for Smart Tools. “After that, you can gradually increase the pressure and resistance.” BFR training almost always involves cuffs; while other compression methods exist, manually or automatically inflated cuffs are the most practical and widely used tool for achieving the right level of blood flow restriction.
Even during warm-ups, I noticed my muscles feeling the burn faster, which set the tone for the entire workout. During my first workout, I was humbled by how intense a set of biceps curls felt with lighter weights than I usually use. My arms were burning, my muscles pumped, and my skin was flushed—all signs that something good was happening. The sensation was noticeable, but never crossed into discomfort. The app let me tweak the cuffs’ occlusive pressure if needed, though I mostly stuck to the recommended settings.
This sensation—the muscle burn feeling—is the cornerstone of BFR’s effectiveness. “The goal is to create a challenging metabolic and energy demand—not because the weight is heavy, but because of the systemic stress,” says Rothstein.
In just four weeks, I experienced muscle gains I didn’t expect.
Within one week, I saw improved muscle engagement and slightly more post-workout soreness than I typically would have from using the same load without cuffs. By the end of the program, I noticed modest muscle gains in my biceps, triceps, shoulders, quads, hamstrings, and glutes. It also saved me time—each session was only 20 to 30 minutes compared to my usual hour-long sessions, but left my muscles feeling fully fatigued.
Overall, I felt much stronger and more confident about returning to heavier lifts now that my body and muscles were primed for it. I wasn’t expecting huge results in just a 30-day timeframe, but I was pleasantly surprised.
Another bonus? Despite feeling the burn during workouts, I didn’t experience increased next-day stiffness, which helped me stay consistent and feeling good throughout the program. This is because BFR cuffs simulate systemic stress without causing the muscle damage associated with heavy lifting, says Rothstein.
Beyond muscle strength, BFR training also outperforms light weights alone for boosting bone growth and density, especially in older adults or those with injuries, according to a 2023 study published in Frontiers in Physiology. Walking with BFR cuffs also shows promise for bone health, according to the same study. While I didn’t personally track bone density during my testing of BFR, knowing it promotes a strong skeleton added major brownie points in my book. (Many women in my life have osteoporosis, including my mom, so I’m always looking for ways to be proactive about my own bone health.)
Certain workout moves were easier with the BFR cuffs than others.
Exercises like biceps curls, bent-over rows, pushups, glute bridges, lunges, squats, deadlifts, and triceps extensions worked exceptionally well because they allowed me to maintain slow, controlled movements, which is key to maximizing metabolic stress with BFR. You can also wear cuffs when using weight lifting machines, although I didn’t specifically integrate them in my own trial. (Using machines can make BFR training even simpler and safer, especially for beginners, since they help reduce the risk of improper form while still targeting specific muscles effectively, says La Cara.)
High-impact or explosive exercises like jump squats, jumping jacks, and skaters didn’t work as well with the BFR cuffs; they felt awkward and didn’t align with the slow, controlled approach that makes BFR effective. Overhead presses also felt challenging due to the cuffs limiting my shoulder mobility by pressing tightly against my upper arms.
Talene doing a set of overhead presses using the upper body SmartCuffs 4.0 and 10-pound dumbbells.
Not everyone should try BFR cuffs, but many people can.
While it’s often marketed as an advanced training tool, BFR is accessible and appropriate for a wide range of people, says Rothstein. “It was heavily designed around the rehab community but is also ideal for anyone at home who doesn’t have heavy weights but still wants enough stimulus to promote muscle adaptation,” he says. That includes beginners, older adults, people recovering from injuries or surgeries, or anyone who wants to improve muscle mass and endurance without lifting heavy. It’s especially beneficial for those recovering from injuries, dealing with conditions like osteoporosis or osteopenia, or simply looking for a time-efficient way to build strength.
However, it’s not suitable for everyone. Some reasons you shouldn’t use BFR cuffs include pregnancy, uncontrolled hypertension, clotting disorders, certain vascular conditions, open wounds, cancer, or cardiovascular disease, says Rothstein. If you’re hypertensive, have a history or risk of deep vein thrombosis, or other severe conditions, BFR is not recommended due to its effect on blood flow restriction, which can exacerbate these issues, he says.
BFR will remain a go-to in my fitness toolbox when I want to put on muscle.
While I still love heavy lifting (which remains the gold standard for muscle growth), BFR cuffs are now a staple in my home workouts, where I don’t have access to heavier equipment. They helped me rebuild muscle safely and efficiently—even with limited equipment.
Dr. Le Cara sums it up perfectly: “If your goal is hypertrophy, muscular endurance, or efficient recovery, BFR can be a game changer—especially for those who can’t tolerate heavy lifting.” Start light, stick to simple movements, and let the cuffs do the work—you might be just as impressed as I was with the results.
Talene Appleton is the fitness editor at Women’s Health, where she covers all things fitness, nutrition, and healthy living. She studied nutrition and exercise science at George Washington University and is a NASM-certified personal trainer and nutritional consultant. Passionate about the intersections between fitness, food, and community, she strives to foster inclusive and holistic wellness narratives for underrepresented populations. When not writing, she can be found hosting dinner parties and exploring new wellness and culinary experiences around New York and Los Angeles. Prior to her role at Women’s Health, she was the fitness and commerce editor at Men’s Health and contributed to General Surgery News, The Food Institute, and The Nessie.
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