Struggling to build muscle despite hitting the gym regularly?
New research suggests the problem isn’t your genetics—it’s likely your approach.
A groundbreaking study challenges everything fitness enthusiasts believe about “hard gainers” and non-responders, while seven additional studies reveal what actually works for muscle growth, fat loss, and performance.
The findings might completely change how you train.
Jump to:
- Hard Gainers Don’t Actually Exist
- Lengthened Bias Training: Overhyped?
- Eccentric Exercise: Less Damaging Than Believed
- MyFitnessPal Accuracy Problem
- AI Can’t Count Your Calories Yet
- Workout Priming Boosts Performance Hours Later
- Post-Workout Stretching: Basically Useless
- Supersets Save Time Without Sacrificing Gains
Hard Gainers Don’t Actually Exist
Many lifters believe they’re genetically doomed when muscle growth comes slowly. Research has even defined “non-responders” as individuals who don’t respond to exercise training.
A new study demolishes this narrative entirely.
Researchers put participants through a ten-week strength training program and identified the so-called “hard gainers” based on poor results. Then came the twist: they repeated the identical ten-week program after a recovery phase.
If genetics truly determined muscle-building capacity, poor responders in phase one should also perform poorly in phase two.
That’s not what happened.
Nobody Failed Twice
While some lifters didn’t gain measurable muscle mass in one phase, not a single participant failed to build muscle in both phases. This held true for both measured muscle groups—biceps and quadriceps.
Something other than genetics caused the poor results.
Training intensity could have been insufficient. Mental focus might have wavered. Training volume may not have matched individual needs—previous research shows some people don’t respond to certain volumes but thrive with different approaches.
According to fitness expert Menno Henselmans, who has over 15 years of coaching experience: “I have coached numerous individuals who had tried everything and couldn’t gain muscle or lose fat, and in every single case it was not true.”
Success Requires Personalization
Some individuals gain muscle effortlessly—protein intake, hard training, done. Others need meticulous attention to details:
- Nutrient timing optimization
- Micronutrient intake management
- Training program fine-tuning
- Lifestyle factors adjustment
- Dietary precision
These individuals aren’t genetically inferior. They simply need to discover their optimal approach.
In the ten or so years I have run the Henselmans PT Course, not a single student has managed not to make gains if they successfully implemented all of the recommendations of the course.
The bottom line: Everyone can get lean, gain strength, and build muscle mass. Genetic variation affects the ceiling, not whether transformation is possible.
Lengthened Bias Training: Overhyped?
The fitness world currently obsesses over lengthened bias training—emphasizing exercises when muscles are stretched. New research suggests the hype exceeds the reality.
Scientists compared lengthened bias versus shortened bias training using specialized machines with cam systems. Participants performed unilateral exercises to failure:
- Reverse flys
- Chest flys
- Lateral raises
- Multi-hip glute kickbacks
After ten weeks, gold-standard MRI measurements revealed no significant differences in strength gains or muscle growth between limbs trained with lengthened versus shortened bias.
Full Range of Motion Matters Most
These results align with previous studies on lateral raises and biceps curls. When exercises utilize full range of motion, emphasizing one portion makes minimal difference—especially with machines providing resistance throughout movement.
Increasing range of motion to greater muscle lengths reliably enhances muscle growth. Simply adding tension at one movement phase doesn’t.
Current trends of maximizing tension exclusively at long muscle lengths probably aren’t necessary for most muscle groups.
Glutes, deltoids, and pectorals may not benefit as much from lengthened bias training due to their length-tension curves. Glutes especially appear to produce maximum tension at relatively short muscle lengths.
Lengthened bias training works best when it increases total tension area under the curve—combining active and passive tension. Research supports this for quadriceps and calves, but even deep squats show diminishing returns. Squatting to parallel may be as effective as ass-to-grass depth for quad development.
Eccentric Exercise: Less Damaging Than Believed
Conventional wisdom holds that eccentric exercise—when muscles lengthen under tension—causes more muscle damage than concentric contractions. A new study challenges this assumption.
Researchers had untrained women perform 75 maximal contractions per biceps—one arm eccentric, one concentric. Both groups were equally unfamiliar with each contraction type.
Despite substantial soreness, no significant differences emerged over four days in muscle damage markers, soreness levels, or strength recovery between groups.
Familiarity Changes Everything
The findings suggest previous studies showing greater eccentric muscle damage actually measured unfamiliarity effects. Nobody trains exclusively eccentrically, so people lack adaptation to that stimulus.
When researchers control for unfamiliarity, differences between concentric and eccentric exercise shrink dramatically.
MyFitnessPal Accuracy Problem
The world’s most popular calorie tracking app has serious reliability issues, according to new research.
Scientists compared MyFitnessPal, Cronometer, and the Canadian Nutrient File (official Canadian food database) by having users input identical food logs.
Problem one: Different users selecting different database entries for identical foods created an average discrepancy of 226 daily calories, with a 95% confidence interval spanning -326 to +776 calories.
Problem two: Even “verified” MyFitnessPal entries don’t correspond well with official databases, averaging 94 calories off daily.
MyFitnessPal provides low reliability and validity.
Cronometer performed significantly better in both reliability and validity. Better alternatives include Cronometer, MyNetDiary, or specialized apps using official databases.
If using MyFitnessPal, manually input actual food labels rather than relying on crowdsourced database entries.
AI Can’t Count Your Calories Yet
ChatGPT and similar AI models can’t accurately track macros from food photos, despite growing interest in this approach.
Researchers tested ChatGPT-4o, Claude 3.5 Sonnet, and Gemini 1.5 Pro on meal photos. The result: 36% mean error percentage for daily calorie intake.
Planning a 20% caloric deficit? You might actually be bulking.
Hidden calories explain the consistent under-reporting—two extra tablespoons of restaurant oil add 200 invisible calories. Butter, sugar, and sauces compound the problem.
While AI models advance rapidly, accurately estimating calories from photos remains unreliable. Weighing portions and using official databases remains the gold standard for macro tracking accuracy.
Workout Priming Boosts Performance Hours Later
Heavy training doesn’t just fatigue muscles—it can enhance performance hours afterward through priming effects.
Trained men performed better athletically—faster sprints, higher jumps—six hours after a heavy squat workout (4 sets of 5 at 85% 1RM).
Multiple studies now demonstrate potentiating effects that overshadow fatigue during specific time windows:
- Post-activation potentiation: Up to one minute post-exercise
- Post-activation performance enhancement: 3-5 minutes afterward
- Extended priming: Around six hours later
These effects involve biorhythm changes, nervous system adaptations, and neuromuscular tissue modifications—particularly temperature and cross-bridge formation processes.
Strategic workout timing could leverage these windows for enhanced performance.
Post-Workout Stretching: Basically Useless
A meta-analysis of 15 studies reached a blunt conclusion: post-workout stretching has no significant effects on muscle soreness, strength, or performance.
Other research confirms stretching doesn’t reduce injury risk either.
Stretching primarily improves stretching ability through neural adaptations—relaxing the nervous system and decreasing pain sensitivity—not by increasing actual muscle length. These adaptations are extremely specific to practiced stretches.
Stretch for specific goals like achieving splits, but general post-workout stretching for recovery or injury prevention doesn’t work.
Supersets Save Time Without Sacrificing Gains
A comprehensive review confirms supersets deserve a place in training programs. They save substantial time without compromising effectiveness.
Researchers examined agonist-antagonist supersets (bench press and rows) and upper-lower supersets (squats and chin-ups). On average, these approaches don’t impair muscle activity, long-term strength development, or muscle growth.
Time savings allow many people to increase training volume, potentially enhancing gains.
If you’re genuinely too fatigued for subsequent exercises, use combo sets with slightly longer rest periods between paired movements. This approach provides time-saving advantages while maintaining performance quality.
The bottom line across all these studies: genetics matter far less than consistent, intelligent application of training principles. Personalization, accurate tracking, strategic exercise selection, and efficient programming outweigh genetic factors for the vast majority of lifters.
