Science Behind Strength Training Techniques

Strength Training Rewires Your Entire Neuromuscular System New 2025 Review in The Journal of Physiology I just went through this paper, and it’s one of the most integrative models of resistance training physiology to date. Here’s what the science shows: - Motor cortex adapts fast Less intracortical inhibition, more facilitation, stronger voluntary drive. - Reticulospinal drive increases Greater descending input to spinal motoneurons during maximal effort. - Spinal circuitry becomes more efficient Reduced inhibitory tone and lower synaptic noise under load. - Motor units recruit earlier and fire faster Higher discharge rates and improved force steadiness. - Motoneuron intrinsic excitability may increase Evidence supports a greater contribution of persistent inward currents in some conditions. - Neuromuscular junction remodeling Animal data show increased transmitter release and receptor density. - Mechanical tension activates mTORC1 Integrin → FAK → phosphatidic acid signaling drives protein synthesis. - Metabolic stress builds mitochondria and capillaries AMPK and PGC 1 alpha support oxidative remodeling. - Hormone spikes are not the main driver of growth Acute testosterone and GH responses do not predict long term hypertrophy. - Adaptations are load and velocity specific Heavy loads maximize 1RM Ballistic intent improves power and early RFD High rep work improves local endurance Resistance training is not just muscle hypertrophy. It is coordinated plasticity from the cortex to the contractile protein. Train the signal, and the structure adapts. Learn more: https://lnkd.in/gCWKqGDs

Stuart Phillips and colleagues just published a really nice review clearing up many of the mechanisms, myths, and misconceptions around muscle hypertrophy (PMID: 41276164) First, the big takeaway is that mechanical tension is the primary driver of muscle growth. When you lift weights, the mechanical load placed on muscle fibers activates mechanotransductive signaling pathways that stimulate muscle protein synthesis and hypertrophy. This process occurs independent of systemic hormone spikes after training. Which brings us to one of the biggest myths in strength training…the temporary increases in testosterone, growth hormone, and IGF-1 after a workout do NOT drive muscle growth. Multiple lines of evidence show these acute hormonal spikes have little to no relationship with hypertrophy outcomes in either men or women. What actually matters is local mechanical tension within the muscle itself. Another common belief that gets challenged in this paper is the idea that “the pump” builds muscle. Metabolite accumulation and cell swelling may feel dramatic during training, but there is very little causal evidence that these mechanisms directly stimulate hypertrophy. They may contribute indirectly by allowing you to train harder or accumulate more volume, but they are not primary drivers of growth. The authors also tackle the popular idea of “sarcoplasmic hypertrophy”, which is the notion that muscle size increases largely through expansion of non-contractile components. According to the review, the evidence for this being a meaningful or separate adaptation is weak. Instead, the dominant adaptation with resistance training remains myofibrillar hypertrophy. In other words, the accumulation of contractile proteins (actin and myosin) that actually generate force. So the fundamentals remain surprisingly simple: 1) Lift weights. 2) Create meaningful mechanical tension. 3) Progressively overload over time. The physiology of hypertrophy is complex, but the principles that drive it are actually very straightforward.

Should you weight train to failure? Near failure? Neither? A new study was just published looking at the effect of resistance training intensity relative to muscular hypertrophy. Specifically, the study looked at taking working sets either to 1 rep in reserve (RIR) vs 4 RIR. "Gym bro' wisdom" has emphasized the need to take sets to complete or near complete failure in order to maximize gains. However, recent work has challenged this dogma. In the current study (see attached) internationally recognized hypertrophy science researcher, Brad Schoenfled et al, two groups of experienced lifters (3-9 years of training experience) were randomized to 2 groups for 10 weeks of training: One group performed all working sets to 1 RIR (that is, within 1 rep of complete failure). The other group exercised to within 1-4 RIR for the first 5 weeks, then gradually increased intensity to 1 RIR over the next 5 weeks. Barbell back squat and barbell bench press were used. BOTTOM LINE: Both groups showed gains in strength and cross-sectional area of muscle volume, with no statistically significant differences between groups, for all intents and purposes. Note that there DOES need to be sufficient intensity and volume to stimulate muscle growth, but there is no need to go to failure. In fact, regularly going to failure puts tremendous stress on both the MSK and the neurological systems, and requires much longer rest intervals to allow for sufficient recovery. Training to sub failure allows for more frequent training, which has been shown to be better for strength and hypertrophy gains. In addition, there also appears to be a difference between isolation exercises, such as biceps curls and seated leg extensions, vs. compound lifts such as bench press, squat, deadlift, and overhead press. Isolation exercises do seem to benefit more from training closer to failure, whereas there appears to be no significant advantage to doing so with compound lifts. (Furthermore, there is more danger of injury in taking compound lifts such as barbell squats to near failure, where it's more difficult to drop the weight if you get stuck.) For less experienced lifters, the vast majority have no clue what true failure looks like. Most lifters stop when they feel uncomfortable and think that they're near failure. But independent research has shown that in most cases they have MANY more reps left in the tank! For our general population patients, in my opinion people make two mistakes: First, they don't do ANY resistance training! (This has implications for aging and age-related sarcopenia.) Second, if they DO perform resistance training, most don't use enough intensity (and good form) to get the most benefit from the exercise. THey may burn some calories, but the muscle doesn't get stronger or bigger, and their time in the gym is not optimized. \https://lnkd.in/eWqvVwDt

Just because you increase force production does not mean the tissue itself has become more resilient. Take a runner with knee pain. They are told a muscle is weak, so they begin squatting. After six weeks their squat improves by thirty percent. That is a positive change, but it does not mean the tissue has adapted. Those early gains are almost always neural. The nervous system has learned to recruit fibers more efficiently, not necessarily to remodel tendon, bone, or cartilage. Strength and resilience are not interchangeable. Neural efficiency adapts quickly. Connective tissue adapts slowly because collagen turnover and bone mineralization require far longer timelines. A heavy squat may stress tissue, but the type of stress matters. Traditional lifting emphasizes short, high-force contractions. Tissues remodel under different conditions: tendons with sustained isometrics, bone with repetitive impact, and cartilage with controlled joint loading. Some will argue that the system is too integrated to separate neural from tissue change. Integration is real, but the timelines are distinct. Neural gains occur in weeks, muscle hypertrophy in months, and tissue remodeling often in a year or more. Conflating them creates false confidence that a stronger lift equals greater resilience. Others will claim injuries cannot be prevented. True, risk cannot be eliminated, but it can be reduced. Dismissing tissue training on that basis is like refusing to wear a seatbelt because accidents still happen. Improving tissue capacity does not guarantee safety, but it lowers the likelihood of overload. Performance should not be confused with durability. Athletes often increase their barbell numbers yet still break down when mileage or sport demand rises. The lift reflects top down capacity, not bottom up resilience. Strength training is valuable, but only when we understand what it is actually changing. You can improve the lift without improving the tissue, or you can use the lift to remodel the tissue. The difference lies in programming with intent.

THE ROAR RECS FOR MAKING MUSCLE All the cardio in the world won't cut it. Research on active women, especially past age 40, shows that even high levels of aerobic activity doesn't translate into any meaningful changes in lean body mass. The only solution is STRENGTH TRAINING. I mean high-intensity power training - heavy lifting for pure strength. This kind of training stimulates your neuromuscular system, activating the maximum amount of muscle fibers. It also keeps those high-energy, powerful type II muscle fibers engaged, which is essential because those are needed for speed, and they're the first to go. I hear from so many perimenopausal women that they feel as if they suddenly lost all strength and power (before any issue with losing lean mass). This is not a misnomer, we see that there is a distinct drop in force generation BEFORE we see any loss in lean mass. This is directly related to estrogen's influence on myosin's binding ability with actin (a weaker bond means a weaker muscle contraction), and the systemic loss of the anti-inflammatory effect of estrogen, reducing the regulation of muscle inflammation and the satellite cell function (meaning, more inflammation reduces the feedback for building new muscle cells) and reduces the quality of the muscle, before overall lean mass loss. The best part is that the benefits of strength training are nearly immediate. Even before your muscles get bigger and stronger, you wake up sleeping muscle fibers and develop neuromuscular connections that result in strength gains after just a few sessions. How to optimize your strength-training results: - LIFT HEAVY Challenge and stimulate your muscles so they break down and repair bigger and stronger. - HOW HEAVY IS TOO HEAVY? Pick up a weight and lift it 8 times. How hard were the last two reps? You have chosen the right weight if you are barely able to eke out that final rep while maintaining good form.(Heavy Resistance Training is a journey, start consistent, with good form, then add load over time; we don't want injuries!!) - LIFT OFTEN Aim for 2-3 days a week. - MIX IT UP Variety is your friend when it comes to making muscle. Anything you'd add? Research links here: https://bit.ly/43hv19v https://bit.ly/4375CxQ https://bit.ly/44twf2A https://bit.ly/3GJHyd8 https://bit.ly/42Z1ykN

“If you don’t lift after 40, you’re not ‘aging gracefully’. You’re slowly training for the nursing home.” Harsh? Yes. But that’s exactly what the data say. ➡️ We lose ~3–8% of muscle mass per decade after 30, with an even steeper drop after 60. What happens to muscle with age if you don’t load it? - Lean mass ↓, strength ↓, power ↓, flexibility ↓, balance ↓ - Fat mass ↑ while basal metabolic rate ↓ → weight gain for the same calories - Bone mineral density ↓ 1–3%/year → fractures, kyphosis, frailty - Intermuscular fat infiltrates → weaker, slower, higher fall risk And this is primary aging amplified by secondary aging: diabetes, obesity, chronic inflammation, physical inactivity. Sarcopenia + obesity = “sarcopenic obesity” – a vicious spiral of less muscle, more fat, less mobility, more disease. Telegraphic science: muscle as a longevity organ 🧬 Muscle mass & strength Hypertrophy + neuromuscular adaptations → force, power, gait, balance. 🔥 Metabolic engine ↑ Basal metabolic rate, ↑ glucose uptake, ↑ fatty-acid oxidation → ↓ metabolic syndrome, ↓ type 2 diabetes risk (≈30% lower T2D in women doing strength training). 🦴 Skeleton protection RT gives ~1–3% gains in bone mineral density and lowers fall risk in older adults. ❤️🧠 Heart, vessels, brain Better endothelial function, lower blood pressure, improved lipid profile, lower CVD risk. Stronger grip and legs = lower all-cause and cardiovascular mortality in large cohorts. 🧠 Cognition & mood Reduced risk of cognitive decline and Alzheimer’s, and moderate effect sizes for reducing depression and anxiety – even in people with chronic pain. Translation: muscle is an endocrine and metabolic organ, not just “meat on your bones”. How to train this week Forget perfection. Aim for minimum effective dose, done consistently. 1️⃣ Resistance training (non-negotiable)  2–3 sessions/week 8–10 exercises covering all major muscle groups 2–3 sets of 8–12 reps at ~60–80% of your max (the last 2 reps should feel challenging but technically clean) Controlled tempo, full range of motion, exhale on effort, no breath-holding Bodyweight + bands + dumbbells are enough to start. Machines are optional. Excuses are not. 2️⃣ Aerobic work (for synergy)  On top of RT: 150–300 min/week  cardio zone 2 (cycling, swimming...) Intervals (short / intense) 2 times a week Add daily walking (8–10k steps) as your base layer. 3️⃣ Balance & mobility (fall-proofing)  5–10 min/day Especially if you’re 60+ or already feel a bit “unstable”. The point is simple: If you don’t give your muscles a regular mechanical signal, biology interprets it as: “We don’t need this tissue anymore.” Muscle is one of the most powerful levers of healthy aging we have. Not optional. A core vital sign. Start this week. Your 70-, 80- and 90-year-old self is watching closely. 🔔 Hit the bell | 👤 Follow me Dr. Guénolé Addor, MD| 📨 Join my newsletter on my website for disruptive, science-based insights you can apply today.

Ground Reaction Forces are the first mechanical signal entering the human movement system. Every squat, deadlift, jump, or sprint begins with the interaction between the body and the ground. This interaction produces ground reaction forces (GRF) — the external forces that define the mechanical loading environment of the entire kinetic chain. Through the relationship: F = m × a τ = r × F ΣM = Iα external forces transmitted through the ground are converted into joint moments and rotational mechanics across the hip, knee, ankle, and spine. What many practitioners overlook is that movement efficiency is not determined only by muscle strength. It depends heavily on how the GRF vector aligns with joint moment arms and how the center of pressure (COP) travels across the base of support. Small deviations in GRF magnitude, vector orientation, or COP trajectory can significantly alter: • joint torque distribution • tissue loading patterns • neuromechanical coordination strategies • long-term injury risk For example, persistent GRF asymmetry greater than 10% between limbs has been associated with increased lower-extremity injury risk, while vector misalignment greater than 5° can systematically elevate joint loading. Understanding these mechanical relationships transforms movement analysis from simple observation into quantitative biomechanical assessment. Biomechanics is not merely the study of movement. It is the study of force architecture within the human body. — MMSx Authority | Applied Biomechanics Lab #Biomechanics #MovementScience #SportsScience #StrengthTraining #Kinesiology #HumanPerformance #MMSxAuthority

I’m not really here to talk about anybody or point fingers, but this is one of the biggest reasons I believe strength and conditioning gets little respect — and why so many people, regardless of background or competency level, claim to be “doing strength and conditioning.” It’s because we, as a field, often allow things like this to go unchecked. I don’t see any scientific or evidence-based rationale for this kind of approach being acceptable. In my opinion, it’s completely unproductive and unsafe. Most importantly, if anyone is working with athletes, how many of them are truly skilled lifters capable of performing something this advanced safely? This type of setup isn’t training — it’s a demonstration or expression, not a form of development. From a scientific standpoint, unstable surface training under maximal or near-maximal loading has no evidence-based justification in strength development. The literature consistently shows that instability decreases force and power output due to reduced neuromuscular efficiency and altered motor unit recruitment. For example, Behm and Sale (1993) demonstrated that strength adaptations are highly velocity- and context-specific — meaning that training stability and load management must reflect the intended performance environment. When instability is added, total force production and rate of force development drop significantly, making it counterproductive for athletes whose performance relies on maximal strength, speed, or power. In essence, the nervous system prioritizes balance over force output, which shifts the adaptation away from strength development and toward unnecessary risk.

The physical quality of explosive strength (power) is essential for success in competitive athletics. Explosive strength qualities may be enhanced via various training methods. One effective method for enhancing explosive strength qualities is the inclusion of the Olympic lifts (OL’s) i.e. the Clean and Jerk, Snatch, as well as their derivatives, i.e. Clean Pull, Snatch Pull in the athlete’s training program design. The OL’s produce high levels of both impulse and rate of force development (RFD). John Garhammer’s classic work demonstrates the 2nd pull of the Clean and the Snatch produce up to 3475 watts (4.7 horsepower) and 3621 watts (5 horsepower) respectively. What is equally impressive is that this force production transpires in 0.140ms to 0.180ms while simultaneously accelerating heavy weight intensities. This is important as most athletic endeavors transpire in .250ms or less while often confronting a considerably sized opponent or implement. Elastic/reactive strength qualities (plyometrics, sprinting) will also improve high impulse and RFD abilities via the neuromuscular enhancement of the stretch shortening cycle (SSC) while also inhibiting of the sensory receptor Golgi Tendon Organs (GTO’s). This allows for a greater contribution of the agonist muscle groups (enhancing the co-activation index) during an athletic task. One of the most stressful plyometric exercises is the depth jump. This exercise requires the athlete to step from a box/platform of a specific height, land upon the ground surface, and immediately reverse direction by jumping vertically. The athlete must be physically prepared with demonstrated appropriate levels of strength, explosive strength, and lead up plyometric activities prior to initiating this exercise in their training regimen. The appropriate box height is also essential to avoid excessive or inferior levels of training stressors. I have presented methods for appropriate box height selection in previous LinkedIn posts. Inappropriate physical preparation and/or box height prescription will increase the athlete’s risk of injury. An additional advantage of the depth jump exercise imparted upon me decades ago by my good friend and national plyometric authority Dr. Donald Chu, is depth jumps may be combined with athletic skills. For example, the depth jump may be combined with a med ball throw, pike jumps and scissors kicks with football punters and jump shots with basketball players. The prescribed athletic task is preferably performed at the peak height of the depth jump. The same principle may be utilized to enhance explosive strength qualities by combining the depth jump with an OL derivative. Once the athlete has demonstrated suitable levels of strength and technical proficiency in the OL’s, a clean shrug and/or snatch shrug may be executed with a depth jump for the sustained enhancement of impulse and RFD in conjunction with the continual training of the OL’s and their derivatives (See video provided).

HEAVY RESISTANCE TRAINING: THE MOST RELIABLE INTERVENTION IN AGING. For years, we’ve heard the phrase: “Some people just don’t respond to resistance training.” This randomized controlled trial in healthy men in their 70s tells a different story. After 16 weeks of supervised heavy resistance training: 💪 +19% maximal strength ⚡ +58% explosive strength 🧬 +14% Type II fiber hypertrophy 📈 82% classified as Robust or Excellent responders Only 5% showed limited benefit. And even those individuals still improved strength. But here’s what makes this study powerful: ✔ Accounted for biological variability ✔ Controlled for measurement error ✔ Integrated strength AND hypertrophy outcomes ✔ Allowed enough time to identify late responders When adaptation is evaluated properly, “non-response” becomes rare. Aging muscle is not resistant. It is responsive — when appropriately loaded. Heavy resistance training remains first-line therapy for preserving muscle, function, and independence. The data continues to make this clear. Soendenbroe C, Andersen JL, Heisterberg MF, Kjaer M, Mackey AL. Heavy resistance exercise training in older men: A responder and inter-individual variability analysis. PLoS One. 2026;21(1):e0338775. Published 2026 Jan 21. doi:10.1371/journal.pone.0338775 https://lnkd.in/eHaKuZVi #StrengthTraining #ResistanceTraining #HeavyResistanceTraining #HealthyAging #ActiveAging #Sarcopenia #MuscleMass #MuscleHealth #ExplosiveStrength #FunctionalStrength #ExerciseScience #ClinicalExercisePhysiology #ExerciseIsMedicine #LongevityScience #AgingResearch #Gerontology #PreventiveMedicine #PerformanceMedicine #MuscleBiology #TypeIIFibers #Hypertrophy #PublicHealth #Rehabilitation #EvidenceBasedPractice #AgingWell #Healthspan #StrengthIsMedicine #LoadTheMuscle