The age-old debate over whether high-repetition, low-weight workouts or low-repetition, high-weight sessions are best for building muscle has taken center stage once again, thanks to recent scientific findings. A new study published in the Scandinavian Journal of Medicine & Science in Sports sheds fresh light on how different resistance training strategies uniquely influence muscle growth, particularly within the hamstrings—a muscle group critical not just for athletes, but for anyone wanting strong, functional legs. With gym culture on the rise across Thailand and Asia, these insights are especially timely for local fitness enthusiasts, trainers, and the expanding community of health-focused individuals.
Understanding the importance of optimizing one’s workouts goes beyond mere aesthetics, touching on long-term health, injury prevention, and athletic performance. Thai readers, who are increasingly active—whether through Muay Thai, running, or weight training—can benefit from tailored advice rooted in scientific evidence. This latest study is particularly significant because it doesn’t just look at how much muscle is gained, but where in the muscle those gains occur, offering a more detailed picture than the usual “more reps vs. more weight” argument that often circulates in Thai gyms (ฟิตเนส).
In the nine-week study, researchers worked with 45 physically active participants who had not recently trained their hamstrings specifically. The participants were separated into three groups: one performed high-load, low-repetition exercises (HL), one did low-load, high-repetition workouts with added blood flow restriction (LL-BFR), and a control group (CON) continued with their regular activity routines without new resistance training. Exercises included staples like stiff-leg deadlifts, front squats, leg extensions, and leg curls—movements familiar to anyone who’s ever stepped into a ฟิตเนสหรือยิม (gym).
The HL group trained at their 12-rep maximum (using weights heavy enough to make 12 reps a challenge), incrementally increasing intensity. The LL-BFR group, conversely, used much lighter weights for a grueling 30 repetitions—while also utilizing arterial occlusion (compression bands) to restrict blood flow to the thighs, simulating the muscle fatigue typically seen with heavier loads. This technique, while less common in Thailand, is gaining interest for its supposed ability to trigger muscle growth with minimal risk of injury. Muscle and tendon growth were measured using advanced 3D ultrasound techniques, offering precise insight into which parts of the hamstring responded to different training styles.
The results were striking and nuanced. The high-load, low-rep group saw significant growth in the semitendinosus (ST, หนึ่งในกล้ามเนื้อหลังขา), coupled with improved knee flexor strength. The low-load, high-rep BFR group, however, had significant increases in the semimembranosus (SM) without notable strength gains. No substantial changes were seen in the biceps femoris long head (BF) or tendon size in any group. For context, the control group—those who didn’t add any new training—didn’t experience any meaningful muscle or strength changes, underscoring the necessity of targeted workouts for muscle development.
Experts highlight that proximity to muscle failure—the point where you cannot complete another rep with good form—is a crucial factor behind these results. Dr. Layne Norton, a renowned powerlifter and PhD cited by GQ magazine, explained that training near failure is what matters most, whether using high weights or lighter ones: “It’s clear from the research that there’s no statistical difference in low reps and high weight compared to its inverse, when controlling for ‘proximity to failure’” (GQ). This insight is supported by Stuart Phillips, a leading researcher, whose studies show both methods can stimulate similar muscle growth if you push yourself close to exhaustion.
This concept resonates with Thailand’s approach to fitness—which emphasizes perseverance and discipline (ความพยายามและความมีวินัย). However, it also points to the risk of misunderstanding: prioritizing either heavy weights or endless repetitions, without true intensity, may be less effective than focusing on effort and progression. Dr. Norton warns about “junk volume,” or sets that are too easy to cause meaningful adaptation—a common pitfall for gym-goers of all levels, from Bangkok to Chiang Mai.
Other recent research complements these findings. A study in the Journal of Applied Physiology, summarized by Men’s Health UK, tracked experienced lifters over eight weeks with varying training volumes (Men’s Health). The key takeaway: muscle size and strength improved across all approaches, but doing more sets didn’t produce greater hypertrophy or strength. In fact, maintaining moderate weekly volume (about 12 sets) was just as effective for muscle growth and even better for maximum strength, provided the workouts were performed with sufficient intensity (i.e., close to failure).
This research confirms that the law of diminishing returns applies to both volume and intensity: more isn’t always better, and individualized, focused training yields the best results. For Thais, especially beginners and intermediate lifters, it means progress can be made without overcomplicating routines or risking overtraining—a concern for today’s busy urban lifestyles (ชีวิตในเมืองที่เร่งรีบ).
Culturally, Thais have long valued gradual improvement through steady, mindful practice, whether in sports or arts like Muay Thai or classical dance. This aligns with the findings: slow, consistent effort—applied with focus—trumps attempts to rush progress through sheer volume or bravado. Traditional beliefs about muscle building, often centered on specific rep ranges or signature workouts, may need updating. Modern science emphasizes flexibility: both heavy and light weights can work, so long as the sets are taken close to failure and progressive overload is respected. “Progressive overload” simply means making your workouts more challenging over time, by increasing weight, reps, or intensity—a concept echoed in ancient Thai proverbs about perseverance.
For Thailand’s rapidly growing fitness community, including those in smaller provinces with access to only basic gym equipment, this is empowering news. Those who cannot lift heavy due to injury, age, or resource constraints can still build significant muscle using lighter weights—if they push to near exhaustion. Blood flow restriction (BFR) training, already gaining popularity among sports science professionals in Bangkok and Khon Kaen, may soon become a staple for rehabilitation and elderly exercisers. However, BFR isn’t for everyone, and should be performed under expert supervision, especially for those with cardiovascular risk factors.
Looking ahead, the field of resistance training science is ripe for continued exploration. The Scandinavian study’s authors made clear that more, larger and longer-term research is needed—especially examining how these principles apply to other muscle groups and in different populations, including older adults and those with chronic disease. For Thailand, this could mean collaborations between sports science faculty at universities like Chulalongkorn and local gyms to develop training protocols tuned to local goals and needs.
What practical steps should Thai readers take starting today?
- Train with Intent: Focus less on whether you’re using heavy or light weights, and more on taking each set close to muscular failure while maintaining good form.
- Personalize Your Plan: Tailor your workouts to your goals and current fitness level. Beginners may benefit from moderate reps and sets, while advanced lifters can consider strategic periodization.
- Avoid Overtraining: More isn’t always better. Too many sets and reps can cause fatigue, reduce strength gains, and undermine interest—leading to burnout, a common problem in modern gym culture.
- Rest and Recovery: Prioritize rest, hydration, and nutrition, which are as important as your in-gym training.
- Seek Professional Guidance: Especially with advanced techniques like blood flow restriction, consult certified trainers or physiotherapists, ideally those familiar with Thai health conditions and training traditions.
While the finer points of muscle science continue to evolve, Thai readers can take comfort from the Buddhist adage “ความพอดี” (the middle way): moderate, sustained effort—delivered with mindfulness and consistency—remains the best route to long-term strength and health.
References: