The Ultimate Guide to natural hypertrophy: Building Real Muscle in 2026

The pursuit of natural hypertrophy demands absolute precision. If you are deeply frustrated, feeling as though you have violently struck a genetic wall while your peers seemingly expand at will, you must immediately discard the anachronistic dogmas of the gym floor. For the drug-free athlete, the margin for error is virtually nonexistent. You cannot annihilate your central nervous system with infinite volume and expect exogenous pharmacology to forcibly repair the trauma. You are governed by strict biological strictures.

The Genetic Wall Myth: Are you training like an enhanced athlete and wondering why you aren’t growing? Stop sabotaging your gains with ‘bro-splits’. Discover the exact science of mechanotransduction that forces natural muscle to grow.

The landscape of skeletal muscle adaptation in 2026 represents the ultimate culmination of a rigorous transition from anecdotal “bro-science” to a highly refined, evidence-based discipline. The modern natural bodybuilder must operate not as a mere weightlifter, but as a biological optimiser - relying on a sophisticated and clinical understanding of mechanotransduction, precise nutritional partitioning, and the chronobiology of recovery to force consistent physiological adaptations. This exhaustive analysis deconstructs the mechanisms of muscle growth, proving unequivocally why natural lifters cannot rely on the high-volume, low-frequency routines of enhanced bodybuilders, and provides a scientifically sound roadmap for monumental, drug-free muscle building.

The Mechanistic Foundation: Mechanotransduction and Tension

In the upper echelons of sports science, the community has reached a concrete, immovable consensus: mechanical tension is the primary, essential, and indisputably most potent non-pharmacological driver of resistance-training-induced muscle growth. Historical models incorrectly placed “metabolic stress” (the pump) and “muscle damage” (soreness) as co-equal pillars of adaptation. Contemporary 2026 research has aggressively clarified that these factors are entirely secondary, overlapping, or merely indirect by-products of tension.

The biological process of growth strictly initiates with mechanotransduction. Muscle fibres are embedded with specialized, hyper-sensitive mechanosensors - specifically the $\beta$-integrin complexes and focal adhesion kinase. When you lift a heavy concentric load and control the eccentric stretch, you literally deform the cell. These sensors detect this severe physical tension and transduce the mechanical physical force into a biochemical signal. This triggers a rigid cascade of intracellular signalling events, violently awakening the mammalian target of rapamycin complex 1 (mTORC1), which serves as the central command hub for regulating automated protein translation and heavy ribosomal biogenesis. Without profound mechanical tension, mTORC1 remains dormant, and growth is physiologically impossible.

Defining the Muscle Protein Synthesis Natural Window

Hypertrophy is not an acute event; it is a chronic adaptation resulting entirely from a positive net protein balance over months and years. Growth mathematically occurs only when the rate of muscle protein synthesis (MPS) exceeds the rate of muscle protein breakdown (MPB) over a deeply sustained period.

To understand the muscle protein synthesis natural timeline is to understand your biological limitations. Unlike the pharmacologically enhanced athlete - whose MPS is perpetually elevated around the clock by synthetic, exogenous androgens - the natural athlete possesses a highly fragile, transient MPS window. The drug-free lifter’s MPS is acutely and exclusively sensitive to the immediate training stimulus and strictly timed nutritional intake. Upon the cessation of a high-tension training session, the natural MPS window spikes, typically remaining elevated for only 24 to 48 hours. If the muscle is not stimulated again shortly after this window closes, the tissue returns to a state of baseline homeostasis.

Current structural data highlights that the accretion of protein chains within the fibre leads directly to an increase in cross-sectional area (CSA). This occurs primarily through myofibrillar protein accretion (the actual contractile tissue) rather than mere sarcoplasmic expansion (fluid and glycogen), which is increasingly classified as a functional, but ultimately secondary, cosmetic adaptation.

Challenging the Acute Hormonal Hypothesis in Natural Bodybuilding Training

A monumental paradigm shift defining natural bodybuilding training in 2026 is the near-total rejection of the “acute hormonal hypothesis.” For decades, coaches mandated incredibly short rest periods (30-60 seconds) to induce temporary, post-workout spikes in endogenous testosterone, growth hormone (GH), and insulin-like growth factor 1 (IGF-1), falsely believing this drove long-term tissue accumulation.

Peer-reviewed clinical evidence has dismantled this theory entirely. These transient, 15-minute fluctuations in systemic hormones have zero statistically significant influence on chronic hypertrophic outcomes in legitimate natural athletes. Growth is an intensely localized phenomenon. The specific muscle fibre responds directly to the tension it independently experiences, governed entirely by local autocrine and paracrine intracellular signalling.

Systemic endocrine changes are essentially irrelevant noise compared to the almighty signal of local tension. Consequently, “hormone-maximizing” techniques are not just useless; they are detrimental. Short rest periods drastically compromise force output on subsequent sets, thereby reducing the primary driver of growth: mechanical tension. You must rest long enough (2 to 5 minutes) to ensure your nervous system can generate maximal force on every working set.

Natural vs Enhanced Bodybuilding: The Critical Physiological Differences

The dichotomy of natural vs enhanced bodybuilding must be respected to programme effectively. An enhanced lifter can walk into a gym on Monday, execute 30 sets of chest exercises, induce monumental muscle damage, and continue to grow until Thursday because their baseline endocrine environment forces anabolism regardless of optimal programming.

The natural lifter attempting this “bro-split” will severely spike Muscle Protein Breakdown (MPB), exceeding their natural capacity to recover. Furthermore, by Wednesday, the natural lifter’s MPS window for the chest has slammed shut, leaving them in a stagnant state of recovery for the remainder of the week without any further hypertrophic progression. Natural athletes must stimulate, recover quickly, and stimulate again. High frequency with moderate, highly-focused volume is the biological imperative.

Intensity of Effort: Proximity to Failure and the RIR Framework

The 2026 clinical approach to training intensity is ruthlessly defined by the Repetitions in Reserve (RIR) and Rate of Perceived Exertion (RPE) frameworks. While the archaic mentality demanded “training to failure” (0 RIR) on absolutely every set, modern human performance research has demarcated a precise “Goldilocks zone” for maximizing hypertrophic signalling while clinically managing systemic, central nervous system fatigue.

The 2025 Proximity to Failure Study

A definitive, landmark 2025 study published in the International Journal of Strength and Conditioning systematically investigated the dose-response relationship between proximity to failure and muscular adaptations in trained natural males. The researchers isolated four critical groups: 4–6 RIR, 1–3 RIR, 0–3 RIR (failure occurring only on the final set), and absolute 0 RIR (where every single set was taken to catastrophic muscular failure).

Goal	Optimal RIR Range	Scientific Finding (2025)
Maximal Strength	1–3 RIR	Comparable strictly to 4–6 RIR; decisively superior to 0 RIR.
Muscle Hypertrophy	0–3 RIR	High variability; 1–3 RIR appears universally effective and vastly safer.
Power Output	4–6 RIR	Superior for maintaining dynamic barbell velocity.
Injury Prevention	>1 RIR	0 RIR groups showed catastrophic injury and high study dropout rates.

The empirical findings are incontrovertible: strength adaptations in compound movements like the bench press were practically identical between the 4–6 RIR and 1–3 RIR groups. Astonishingly, the cohorts training to absolute total failure (0 RIR) yielded slightly inferior strength and growth results due to accumulated systemic fatigue.

For hypertrophy, the data explicitly suggests that training consistently 1-3 repetitions shy of failure is the absolute ceiling of necessity for recruiting high-threshold motor units. Crucially, the 0 RIR protocol was forcibly terminated for several subjects due to acute safety concerns. For the natural lifter, the fatigue-to-stimulus ratio of absolute failure is ruinous. It elongates recovery timelines and actively prevents you from executing the necessary weekly volume.

Motor Unit Recruitment and Barbell Velocity

The fundamental rationale for training close to failure is the selective recruitment of high-threshold motor units. Dictated by Henneman’s Size Principle, the central nervous system recruits smaller, endurance-focused motor units first. As force demands rapidly escalate - or as those smaller units suffer fatigue - the CNS is forced to deploy larger, highly hypertrophic (Type II) fast-twitch units.

In elite 2026 programming, velocity loss is strictly measured as a proxy for this internal physiological fatigue. Empirical evidence confirms that a velocity loss of 20–40% within a working set is indicative of total motor unit recruitment required for maximal hypertrophy. Conversely, a 0–10% loss is characteristic of power and speed training. For natural athletes, violently pushing every single set beyond a 40% velocity loss (grinding to a total halt) severely compromises neuromuscular recovery, unnecessarily adding 24 to 48 hours to the healing timeline.

Training Volume: The Quantitative Driver of Natural Muscle Growth

Volume - quantified clinically as the number of “hard sets” (sets taken strictly within the 0–3 RIR threshold) per muscle group per week - remains the most significant quantitative variable dictating natural muscle growth.

Extensive meta-analytical data and longitudinal 2026 studies have validated a harsh dose-response relationship between set volume and tissue cross-sectional area, plateauing abruptly at a point of severe diminishing returns.

The clinical consensus defines the “lower threshold” required for hypertrophy at approximately 10 high-quality sets per muscle group, per week.

• Maintenance/Minimalist (1–4 Sets): Secures ~64% of maximal gains. Highly efficient for preserving tissue during severe life stress.
• Standard Hypertrophy (10–15 Sets): The absolute optimal biological zone for the vast majority of natural intermediate athletes.
• High Volume/Overreach (16–22+ Sets): Exclusively beneficial for advanced, highly-adapted lifters targeting stubborn muscle groups. Demands monastic recovery protocols.
• Ultra-High Volume (30–50 Sets): Physiologically senseless for the natural lifter. Generates excessive “junk volume,” catastrophic systemic inflammation, and invites immediate injury.

Advanced practitioners deploy strict “volume ramping,” initiating a mesocycle at the 10-set baseline and micro-dosing volume sequentially up to 20 sets before executing a mandatory deload, calculating their precise mathematically-derived Maximum Recoverable Volume (MRV).

Frequency and the Volume-Matching Principle

The historical debate regarding optimal training frequency has been clinically terminated. In 2026, the data is stark: when total weekly set volume is perfectly matched, training frequency (e.g., executing all sets on 1 day vs spreading them over 3 days) does not generate a statistically significant divergence in acute tissue growth in a controlled laboratory.

However, in the brutal reality of the gym floor, higher frequencies (stimulating a muscle 2–4 times per week) are drastically superior. Efficacy stems entirely from set quality. Spreading 15 sets of heavy pectoral training across three distinct sessions allows the athlete to deploy heavier loads and maintain flawless, high-tension technique. Attempting a solitary, gruelling 15-set session guarantees that axial fatigue will radically blunt force production and tension generation by the 6th set, rendering the subsequent 9 sets as pure, unadulterated junk volume.

Respiratory Muscle Training (IMT): The 2026 Breakthrough for Strength

A groundbreaking frontier of biomechanical enhancement for the drug-free athlete in 2025–2026 is the deployment of Inspiratory Muscle Training (IMT). Previously sequestered to endurance cycling and alpine sports, its clinical application in heavy natural bodybuilding has been heavily substantiated.

A 2025 controlled trial analysed the hypertrophic and force-production impacts of a 4-week respiratory protocols on natural lifters. The cohort executing daily IMT demonstrated a staggering 6.3% greater improvement in pure 1RM power output compared to the control group. This force escalation was causally linked to a massive morphological increase in diaphragm thickness during both the inspiratory (20.36%) and expiratory (19.46%) phases.

The mechanical physics behind this are bilateral: a hyper-trophied diaphragm drastically amplifies intra-abdominal pressure and lumbar spinal rigidity, permitting zero-loss kinetic force transfer during heavy axial loads (squats and deadlifts). Concurrently, the IMT cohort registered a 25.77% decrease in systemic Rate of Perceived Exertion (RPE). A superhuman respiratory engine chemically reduces the suffocating “feeling of effort,” allowing natural athletes to endure agonizing high-repetition sets without cardiovascular capitulation.

Advanced Biomechanics: Length-Mediated Hypertrophy and ROM

The archaic dogmatism of “full range of motion at all times” has been clinically superseded by a targeted “lengthened bias” architecture. Overwhelming 2026 longitudinal data dictates that mechanical tension fundamentally induces the most severe hypertrophic response explicitly when the muscle fascicles are stretched under heavy load.

The phenomenon of stretch-mediated hypertrophy represents the zenith of modern biomechanics. However, a high-resolution 3D MRI diagnostic study in 2025 categorically proved that this response is not universal across the human anatomy.

• Highly Responsive Musculature: The quadriceps (rectus femoris), hamstrings, and the massive long head of the triceps exhibit extreme hypertrophic sensitivity to stretch. For instance, heavy overhead triceps extensions mathematically provoked 1.4x the diametric growth compared to standard triceps pushdowns when volume and load were perfectly equated.
• Non-Responsive Musculature: The pectorals, lateral deltoids, posterior deltoids, and gluteus maximus demonstrated zero statistically significant divergence in CSA growth between “stretch-biased” and “shortened-biased” protocols.

This anatomical reality birthed the strategic implementation of “lengthened partials” - executing repetitions strictly in the deepest, most agonizing bottom-half of the ROM. For natural lifters seeking maximum efficiency, these partials guarantee that responsive muscles endure the maximum possible tension precisely in the biomechanical region that forces adaptation.

Repetition Tempo and Execution Control

Execution is the mechanism by which tension is delivered. In 2026, clinical biomechanists prescribe a rigid, controlled repetition tempo oscillating between 2 and 8 total seconds. The central dictum is the absolute control of the eccentric (lowering) phase to enforce maximal mechanotransduction while aggressively mitigating connective tissue shearing.

While protracted eccentric phases (3–4 seconds) are exceptionally proficient for generating necessary micro-trauma and supreme motor control, intentionally slow concentric (lifting) phases are strictly forbidden. Artificially slowing the concentric phase instantly reduces the total external load the athlete can move, directly handicapping total motor unit recruitment and annihilating mechanical tension. The mandate is clear: lower with surgical precision, explode upward with maximum intended velocity.

Periodisation Models Designed for the Natural Athlete

Periodisation is the strictly mathematical planning of the athletic calendar to obliterate stagnation and manage cumulative systemic fatigue.

• Linear Periodisation: Demands a rigid, mathematical increase in intensity paired with a decrease in volume over several months. Exceedingly proficient for novices, providing a highly legible trajectory for neurological strength adaptations.
• Non-Linear/Daily Undulating Periodisation (DUP): Implements violent, frequent fluctuations in intensity and volume within a microcycle (e.g., executing a “Hypertrophy Day,” followed 48 hours later by a heavy “Power Day”). This framework is vastly superior for intermediate natural athletes, successfully circumventing the “repeated bout effect” and maintaining intense neurological novelty.
• Autoregulation (The 2026 Gold Standard): Flexible periodisation has conquered the coaching elite. Rather than submitting blindly to a pre-calculated spreadsheet load, the elite natural athlete violently adjusts the daily tonnage based on realtime biometric feedback, velocity loss, and perceived readiness. Autoregulating cohorts mathematically decimate rigid-programming cohorts in longitudinal studies because they possess the analytical freedom to push to the absolute brink on days of high systemic readiness, and critically, retreat on days of high inflammation.

The Nutritional Engine: Partitioning, Leucine, and Mitochondrial Health

For the natural athlete, caloric consumption is entirely distinct from drug-free muscle building. It is an exercise in strict “nutritional partitioning” - forcing ingested energy explicitly into myofibrillar synthesis rather than adipose tissue lipogenesis.

In 2025, a landmark paper published in Nature Cell Biology completely redefined our understanding of the amino acid leucine. Previously hailed merely as the brute-force trigger for mTORC1, clinical researchers identified a profound secondary pathway: the Leucine-GCN2-SEL1L axis.

Leucine violently inhibits the amino acid stress sensor GCN2, which consequentially aggressively reduces the concentrations of the protein SEL1L at the mitochondrial membrane. Because SEL1L is responsible for degrading proteins on the outer mitochondrial membrane (OMM), its suppression by leucine actively stabilizes the cellular power plants.

The biological result is astonishing: Leucine operates as a dual-action super-compound. It simultaneously detonates the biochemical signal to assemble new muscle tissue while structurally supercharging the mitochondrial respiration required to produce the massive ATP demands of heavy lifting.

In terms of caloric surplus management, the archaic “dream bulk” is dead. The Partitioning Ratio (P-ratio) dictates that a precise, microscopic surplus of merely 200–300 strictly tracked calories above maintenance is the biological maximum required for natural lifters to optimize MPS. Any surplus beyond this threshold results in linear adipose tissue gain, plunging insulin sensitivity, and subsequent systemic inflammation that blunts future growth.

Protein Dynamics and the Leucine Threshold

Total daily protein intake and its extreme temporal distribution are the absolute foundational pillars of drug-free hypertrophy.

The strict 2026 clinical recommendation for the natural bodybuilder stands steadfastly between 1.6 and 2.2 grams per kilogram of total body weight daily (g/kg/d). While aggressive deficits demand intakes pushing 2.7 g/kg/d to prevent severe catabolism, 1.6 g/kg/d represents the mathematical ceiling where MPS is forcefully maximized in an isocaloric or surplus environment.

However, total daily intake is subservient to the “Leucine Trigger.” Every solitary meal must cross a hard biological threshold - delivering precisely 2.5 to 3.0 grams of free leucine - to forcefully unlock mTORC1.

• Whey Protein Isolate: Requires precisely 25–30g to hit the threshold.
• Lean Animal Flesh (Chicken/Beef): Requires 100–120g of cooked mass.
• Plant Sources (Soy/Seitan): Suffer from significantly lower fractional leucine content. A soy isolate requires a massive 40g bolus, while complete plant-based athletes must carefully titrate the volume of their meals or deploy free-form leucine powder to force their plant proteins to mimic the aggressive anabolic signalling of animal flesh.

The Evidence-Based Supplement Landscape for Drug-Free Muscle Building

The sports supplement industry is a desolate wasteland of fraudulent claims and aggressive marketing. For the serious natural athlete pursuing drug-free muscle building, the clinical arsenal is incredibly narrow, aggressively verified, and ruthlessly effective.

• creatine monohydrate: The undisputed, heavily replicated apex of sports science. It aggressively expands intracellular phosphocreatine buffering, permitting the athlete to execute heavier loads for higher volumes. This directly forces superior mechanotransduction and pure myofibrillar synthesis. Take 5 grams daily, forever.
• Omega-3 Fatty Acids (EPA/DHA): Dosed at 2-3g daily, these highly bioactive lipids weave into the phospholipid bilayer of the muscle cell, severely sensitizing the tissue to anabolic signalling while suffocating systemic inflammation.
• Citrulline Malate: Required at a precise 6-8g clinical dose, ingested 40 minutes pre-bout. It violently forces vasodilation and clears toxic metabolic waste from the working muscle, delaying acute fatigue.
• Vitamin D3: Central nervous system efficiency, bone mineral density, and testosterone optimization are strictly reliant on high serum 25(OH)D levels.
• Branch Chain Amino Acids (BCAAs): Scientifically categorized in 2026 as an expensive, metabolically useless placebo if total daily protein matches clinical targets.

Recovery: The Chronobiology of Muscle

Attempting to build monumental tissue without mastering the chronobiology of sleep is biological treason. In 2026, sleep is recognized not as a passive state, but as a “Tier 1” active training variable.

The molecular cost of sleep deprivation is catastrophically catabolic. A solitary night of total sleep deprivation immediately obliterates Muscle Protein Synthesis by 18%, detonates cortisol levels by 21%, and severs endogenous testosterone production by 24%. Chronic sleep restriction creates a severe physiological state of “anabolic resistance,” permanently blunting the cellular response to leucine and tension.

During the deep, restorative N3 phase of sleep, the pituitary gland unleashes massive pulses of growth hormone. Concurrently, sleep heavily governs the immune system’s anti-inflammatory cytokines. Clinical biopsies on sleep-restricted lifters revealed a massive elevation in the structural protein NFAT1 - a biochemical red flag for catastrophic inflammatory signalling. For the natural lifter, 8 to 9 hours of uninterrupted, high-quality sleep is the non-negotiable biological tariff required to build tissue.

Debunking Toxic Myths in the Natural Physique Arena

To operate efficiently, you must purge your intellect of debilitating gym myths.

Myth 1: “Toning” vs. “Bulking” Exercises This is a physiological fiction. A barbell does not understand “toning.” Muscle definition is exclusively the product of retaining deep muscle mass while stripping away the lipid layer (body fat). The brutal, heavy compound lifts that built the mass in a caloric surplus are the exact same instruments required to preserve that mass in a deficit. “Toning” is simply bodybuilding while starving.

Myth 2: “Shocking” the Muscle The biological system adapts strictly to aggressively progressive overload - adding millimetric increments of weight or executing superior repetitions on the exact same biomechanical movement over years. Constantly randomizing your exercise selection (“muscle confusion”) actively prevents the central nervous system from achieving the elite motor proficiency required to generate true, tissue-rending mechanical tension.

Myth 3: The “Abs are Made in the Kitchen” Fallacy A caloric deficit is mandatory to reveal the abdominal wall by removing visceral and subcutaneous fat. However, the rectus abdominis is a striated skeletal muscle identical to your bicep. If you do not apply punishing, progressive overload (heavy weighted crunches, strict hanging leg raises), the muscle will remain thin, flat, and entirely un-aesthetic even at single-digit body fat percentages.

Myth 4: Extremely Heavy Weights are the Sole Mandate for Growth While lifting >80% of your 1RM is mathematically mandatory to recruit sheer neurological strength, it is not required for cellular hypertrophy. Clinical consensus has proven that incredibly light loads (as low as 30% 1RM) force mathematically identical hypertrophic adaptations provided the set is taken deeply into the 0-2 RIR threshold. This is a crucial biological loophole for the advanced, battered natural lifter seeking to protect their articular cartilage from heavy axial loads.

Practical Programming: Actionable Frameworks for All Levels

A masterclass programme balancing mechanical tension, clinical recovery, and metabolic health.

The Novice Protocol (0–1 Year Experience) The objective is total skill acquisition and forced neurological adaptation.

• Frequency: 3 strict sessions per week (e.g., Monday, Wednesday, Friday).
• Selection: 1 Heavy Squat, 1 Hinge (Deadlift/RDL), 1 Horizontal Push (Bench), 1 Vertical Pull (Pull-up).
• Execution: 3 working sets of 8–12 repetitions.
• Progression: Ruthless linear progression. Add 1.25kg to the bar every session until failure.

The Intermediate/Advanced Protocol (2+ Years) The objective is mass accumulation via frequency and volume allocation.

• Architecture: Upper/Lower or Push/Pull/Legs strict splits.
• Frequency: 4–5 aggressive sessions per week.
• Volume: 10–20 high-quality sets per target muscle group per week.
• Intensity: Locked strictly into the 1–3 RIR zone. Absolute failure reserved exclusively for isolation, single-joint mechanics.
• Advanced Tech: Implement daily 30-breath IMT protocols.

The Over-40 Natural Bodybuilder The primary constraints shift violently from stimulus delivery to joint preservation and severe recovery management.

• Frequency: 3–4 days per week maximum. Mandatory 48-hour systemic rest periods.
• Selection: Aggressive prioritization of locked-in machine networks and converging cables to eradicate joint shearing forces while isolating pure mechanical tension.
• Nutrition: Extreme focus on elevated protein targets (2.2 g/kg/d) to chemically bypass age-induced anabolic resistance.

Conclusion: The Future of Natural Hypertrophy

The trajectory of natural hypertrophy beyond 2026 relies entirely on the ruthless intersection of human effort and cold, calculated biology. The modern drug-free bodybuilder is not a reckless gym rat addicted to the pump; they are a highly analytical biological optimiser. By entirely respecting the violent requirements of mechanotransduction, maintaining extreme mitochondrial efficiency via precise leucine administration, and defending the sacred regenerative window of deep sleep, you can shatter genetic ceilings. Apply the rigorous, uncompromising power of science to the brutal art of the physique, and force the ancient adaptation of monumental growth.

Frequently Asked Questions

How is natural hypertrophy different from enhanced? Natural requires high frequency and precise volume management without destroying the CNS, as you lack exogenous hormones to force recovery.

Does muscle soreness mean growth? No, mechanotransduction is the primary driver. Extreme soreness simply indicates muscle damage, which can actually impede optimal recovery and subsequent training frequency.

How long does the natural anabolic window last? Muscle protein synthesis is critically elevated for only 24-48 hours post-training, necessitating repeated stimulation.

Can natural bodybuilders still get a ‘pump’? Absolutely. While the pump (metabolic stress) is secondary to mechanical tension for growth, proper hydration, carbohydrates, and non-stimulant boosters like L-Citrulline create massive vasodilation without drugs.

How crucial is the eccentric phase for natural muscle growth? The eccentric, or lowering, phase is critical. Clinical data shows controlling the eccentric under heavy load causes profound microtrauma and maximizes the mechanotransduction signaling necessary for natural hypertrophy.