239 ‒ The science of strength, muscle, and training for longevity | Andy Galpin, Ph.D. (PART I)

Intro (00:00:00)

• Welcome to the Drive podcast hosted by Peter Attia.

Andy’s path to expertise in exercise (00:00:08)

• Andy Galpin expressed excitement for the discussion, despite not being in person.
• He has a long-standing interest in exercise, which is central to longevity and quality of life, alongside nutrition, sleep, and pharmacotherapy.
• Peter Attia focuses on exercise in his podcast, particularly on strength, stability, and cardiorespiratory fitness and its impact on metabolic states.
• The conversation is expected to cover strength training, hypertrophy, and related topics of interest.
• Andy shared his athletic and educational background; growing up in a small town, playing sports in high school, college football, and pursuing a degree in exercise science.
• After managing a facility for professional athletes, he earned his master's in Human Movement Sciences and Ph.D. in Human Bioenergetics by 2011.
• Currently, he is the director for the Center for Sport Performance and runs a lab at Cal State Fullerton.
• His professional experience includes training athletes across various sports, except for racing.
• Andy's research and interests stem from his athletic experiences, the significance of effective training and recovery, and a deep-seated passion for helping athletes with goals such as the Olympics in less financially-supported sports.
• He emphasizes the importance of preparation, hard work, learning, and personal commitment in both sports and academia.

Contrasting strength, power, and force production and how they inform us about training for longevity (00:07:09)

• Powerlifting is focused on maximum force production in one repetition and includes three lifts: deadlift, bench, and squat.
• Olympic weightlifting includes two lifts, the snatch and the clean and jerk, requiring both strength and speed, indicating a powerful activity.
• Strongman competitions involve high strength activities repeated several times, but not one-rep max scenarios like powerlifting or weightlifting.
• Training like a powerlifter optimizes pure strength development, while training like an Olympic weightlifter enhances power, involving coordination and proprioception.
• Strongman training encourages very strong and functional movements that are relevant to everyday life tasks.
• The importance of hypertrophy, or muscle growth, found in bodybuilding and focused on muscle mass and leanness without function, is contrasted with powerlifting and weightlifting.
• Sports like CrossFit showcase a mix of strength, muscle endurance, and the ability to recover quickly through multiple workouts and movements in a short period.
• Track and field exemplify velocity-focused training, aiming for peak speed.
• The different sports provide models for training various aspects of physical fitness, such as strength, power, muscle size, muscular endurance, and cardiovascular endurance.
• Each sport reflects a different emphasis on training adaptations that contribute to overall fitness and longevity.

Training Adaptations and Functional Human Longevity

• Understanding the differences in training adaptations across sports like powerlifting, Olympic weightlifting, bodybuilding, strongman, CrossFit, and track and field helps to determine how to train for specific fitness goals.
• These sports exemplify different elements of physical fitness, including speed, power, strength, muscle size, muscular endurance, and cardiovascular endurance.
• Each type of training corresponds to different attributes on a spectrum of physical capabilities necessary for overall health and longevity.

Muscle energetics: Fuels that provide energy to muscles, and the importance of protein (00:16:03)

• Skeletal muscle is a crucial tissue that supports locomotion, serves as an amino acid reserve, and plays a role in regulating metabolism.
• There's a continuous turnover of amino acids with proteins constantly being broken down and synthesized for various bodily functions.
• Muscle tissue functions energetically using different systems, including ATP and phosphocreatine for immediate energy, carbohydrates for short-term energy, and fats for long-term energy.
• Protein in the muscle acts more as a building material for cells and bodily functions rather than as a primary energy source, though it can be used for energy in survival scenarios.
• Insufficient protein intake can lead to muscle loss and a redistribution of proteins within the body, reinforcing the importance of adequate protein consumption.
• There's clear evidence that more muscle mass correlates with longevity, as does strength, with strength being the more impactful factor when normalized for muscle mass.
• Muscle not only contributes to physical performance but also to aging and longevity, forming a strong argument against skimping on protein in the diet.

The structure and microanatomy of muscle, muscle fibers, and more (00:29:34)

• Human movement is driven by the nervous system, which provides direction or signal.

• Movement involves a three-step process: neural signaling, muscle fiber contraction, and connective tissue pulling on bones.

• Muscle fibers are surrounded by connective tissue, bundled together, which then forms a tendon attached to the bone.

• Muscles adapt quickly and are plastic, while connective tissue is less plastic and has minimal blood flow and metabolic demand.

• Skeletal muscle fibers are the largest cells in biology by diameter and have multiple nuclei.

• Multiple nuclei in muscle cells decentralize cellular functions and are more adaptive but harder to control.

• Professional athletes might have more nuclei per volume, which could contribute to their ability to adapt and handle training volumes.

• Nuclei are not all the same; their count, shape, and location affect their function, influencing repair and response to injury.

• Recent understandings show subtypes of nuclei with specific functions, such as those that surround mitochondria or regulate injury.

• The nature versus nurture debate regarding the increase in nuclei due to genetics or adaptation to training persists, with ongoing research.

• Skeletal muscle cells vary in size from millimeters to inches in length, structurally different than cardiac cells.

• Skeletal muscles are uniquely multiply nucleated, meaning they have several thousand nuclei per cell, which allows for larger cell size and adaptability.

• Nuclei within the muscle cells may act independently, with no clear central command; this decentralization is advantageous for the cell's adaptability.

• Studies on the role of nuclei in muscle cell growth (hypertrophy) explore the concept of "myonuclear domain limitations," suggesting a cell's growth is limited by its nuclei control.

• There's a concept of "muscle memory" where it's easier to regain muscle than to gain new muscle, potentially explained by preservation of nuclei after training and detraining.

• The understanding of myonuclei and their role in muscle plasticity is still evolving, with new research frequently updating previous beliefs and leading to the identification of different subtypes of myonuclei.

Energy demands of skeletal muscle compared to other tissues in the body (00:41:40)

• Muscle cells have high energy needs relative to other cells in the body.
• The liver, though not as energetically demanding, plays a crucial role in glucose homeostasis and has remarkable regenerative ability.
• The brain is an incredibly metabolically greedy organ that relies on the liver for glucose homeostasis.
• Muscle tissue is responsive and does increase basal metabolic rate when mass is added, but the increase is not as substantial as some believe.
• Skeletal muscle is efficient and often awaits activation to conserve energy, except when immediate energy demands arise.
• Non-exercise activity thermogenesis (NEAT) plays a significant role in energy expenditure and weight maintenance outside of formal exercise.

How a muscle contraction works and why it requires ATP (00:51:37)

• Motor units include a nerve and the muscle fibers it innervates; fine control requires more motor units.
• In the eye, motor units can be nearly one-to-one for precise control.
• Larger muscles like the glutes have fewer nerves controlling many fibers, resulting in powerful but less precise contractions.
• Henneman's size principle states that some motor units are easily activated (low threshold), while others require more stimulation (high threshold).
• Muscle contraction is an interplay of chemical and electrical signals involving sodium, potassium, and chloride ions.
• Patient-assisted suicide using potassium demonstrates the importance of ion gradients for heart function.
• Action potentials occur when there's a sufficient voltage change caused by ion movement; skeletal muscle fibers contract fully once activated.
• Muscles can feel continuously contracted if fibers activate repeatedly without complete recovery.
• ATP is required for the sodium-potassium pumps to reset ion gradients for subsequent contractions.

Muscle fibers: modulation between fiber types with movement and changes in fibers with training and aging (00:57:18)

• Motor units are composed of muscle fibers of the same type, either slow-twitch or fast-twitch.
• Force production is varied by activating different numbers of motor units, starting with low threshold (slow-twitch) units.
• Fast-twitch fibers are metabolically demanding and primarily activate under high force demands.
• With aging, there is little reduction in slow-twitch fibers, but fast-twitch fibers decline without high force activities, leading to a process called fiber type grouping.
• Unused fast-twitch fibers can be taken over by neighboring slow-twitch motor units.
• Muscles display a mixture of fast and slow-twitch fibers, which can affect the smoothness of muscle contractions.
• Specific muscles, like the Soleus in the calf, are predominantly composed of slow-twitch fibers to support posture and continuous use, while muscles like the gastrocnemius can be more fast-twitch dominant.
• Variation in fiber composition is significant between muscles, and there can be substantial person-to-person differences.
• The VL (vastus lateralis) of the quadriceps can vary widely in fiber type composition, ranging from mostly slow-twitch in endurance athletes to predominantly fast-twitch in sprinters.

Andy's study of twins demonstrating the difference in muscle fibers between a trained and untrained individual (01:07:56)

• Andy Galpin conducted a study on monozygous twins with a 35-year difference in exercise habits to understand the impact of training on muscle fibers.
• One of the twins was an endurance athlete with documented training, while the other never exercised.
• Despite the difference in exercise habits, the twins were nearly identical in appearance, with minor differences in body fat.
• The study involved comprehensive testing, including DEXA scans, VO2 max, muscle biopsies, psychological evaluations, and more.
• Results indicated that muscle mass was nearly identical in both twins.
• The untrained twin had slightly more body fat but similar or superior muscle quality, leg extension strength, and vertical jump capabilities compared to the athlete twin.
• The exercising twin had expected endurance adaptations such as higher VO2 max and better blood lipid panels.
• The non-exerciser had stronger metrics in aspects not associated with endurance training, such as muscle power.
• Muscle biopsies revealed the non-exerciser's fiber type distribution was typical, with about 20% hybrid fibers expressing both fast and slow-twitch characteristics within single cells.

Microanatomy of fast-twitch and slow-twitch muscle fibers (01:18:36)

• Fast-twitch fibers contract rapidly and are larger, more glycolytic, containing enzymes for anaerobic glycolysis, more glucose, less intramuscular triglycerides, and are typically less abundant with aging or in endurance athletes.
• Slow-twitch fibers are fatigue-resistant, use fats and glucose as fuel, and have more and larger mitochondria, but contract with lower velocity.
• Force production in muscle fibers is primarily determined by cross-sectional area, while power also considers velocity.
• Specific tension is used to measure relative strength in muscle fibers, showing fast-twitch fibers have greater power when size is normalized.
• The contraction mechanism involves myosin and actin filaments overlapping, not touching, where myosin heads grab and pull actin filaments closer, causing the muscle to contract.
• Cross-bridges between myosin heads and actin determine the forcefulness and speed of contraction; more cross-bridges result in more effective contractions.
• The myosin heavy chain on the myosin head is what determines muscle fiber type and contractile speed.
• ATP provides the energy for muscle contractions, powering the myosin heads to prepare for and execute a strong connection with actin.
• Muscle fiber contractile speed is driven by how quickly the myosin ATPase can hydrolyze ATP.
• Gel electrophoresis is used to differentiate between fast-twitch and slow-twitch fibers, with molecular weight indicating the speed of the myosin heavy chain and classifying muscle fiber types.
• Muscle fiber type is associated with twitch velocity, rather than size, and is influenced by metabolic capabilities or twitch velocity.

Factors that determine one’s makeup of muscle fibers and how adaptable they are with training (01:31:15)

• Untrained identical twins typically have muscle fiber profiles close to textbook distributions: approximately 50% slow-twitch, 30% fast-twitch 2A, and 20% 2X.
• Pure 2X muscle fibers are extremely rare, often seen in muscles that have been de-innervated for decades or in people with spinal cord injuries.
• Most analyzed fibers are hybrids, with pure 2X fibers constituting about 0.1% of fibers.
• Pure 2X fibers are often incorrectly reported in literature due to inadequate methodologies that cannot distinguish between hybrids and pure types.
• Nutrition can influence muscle fiber composition, with certain substances inducing changes in fiber type.
• Physical training can cause significant changes in fiber types, with such adaptations seen clearly in studies.

Case study on muscle fiber types and training adaptations (01:31:15)

• A research case study showed that an untrained twin had the expected fiber composition, while the twin trained in exclusively cardiovascular exercise had 95% slow-twitch fibers.
• Activity and certain conditions, like space flights, are linked with increased concentrations of 2A2X fibers, which are generally associated with poor health.
• Physical training tends to convert 2A2X hybrids into pure 2A fibers.
• It is hypothesized that a triplet brother who was a powerlifter might have 70% fast-twitch 2A fibers and 30% type one, with very few hybrids.
• Fiber type plasticity seems to have no limits within normal human conditions.

Muscle fiber adaptation across ages (01:31:15)

• Muscle fiber type is highly malleable and adaptable to training regardless of age.
• Dramatic changes in muscle fiber types can occur within weeks of training, even in older individuals.
• The less trained an individual is, the faster the initial adaptation to training.
• There appears to be no maximum age for muscle fiber adaptability.

Hypertrophy and what happens at the cellular level when a muscle grows (01:40:49)

• Hypertrophy refers to an increase in muscle fiber diameter or cross-sectional area.
• During hypertrophy, muscle fibers' width expands similar to how adipocytes store more triglycerides when they enlarge.
• Sarcoplasmic hypertrophy (increase in muscle size due to fluid retention) versus myofibrillar hypertrophy (where actin and myosin contractile proteins increase) has been debated.
• Recent studies have begun to explore whether both fluid retention and contractile tissue enhancement occur during different training phases.
• Technological limitations previously made it difficult to distinguish if increases in muscle size were from sarcoplasmic or myofibrillar hypertrophy.
• New assay methods are now allowing researchers to more accurately measure changes in muscle tissue without damaging it through incorrect freezing and thawing methods.
• Understanding these differences is key to explaining why bodybuilders might have larger muscles but may not be as strong as weightlifters, with neurological adaptations and intracellular changes playing a role.
• Optimal lattice spacing between actin and myosin is crucial for muscle contraction, and hypertrophy could theoretically compromise this spacing and affect strength.
• Muscle hypertrophy that doesn't correspond with an equal increase in contractile units could lead to larger yet not stronger muscles.
• Two-thirds to seventy percent of body weight is water, with it being present in all cells, including muscles, affecting energy storage and the need for glucose in muscles.
• Bodybuilders, like Jay Cutler, might restrict salt intake to manage sodium-related fluid retention, as excess sodium can lead to various adverse effects.

How athletes quickly cut water weight and the rehydration process (01:49:59)

• Athletes may reduce water weight by over 15 pounds in 48 hours and must rehydrate carefully to avoid health issues.
• Proper understanding of electrolyte balance is crucial to avoid complications such as kidney issues, bloating, or dehydration.
• Rehydrating strategies should take into account osmolarity to ensure intracellular fluid replenishment, particularly for organ functionality.
• A gradual approach to rehydration is advised, with approximately 110-125% of lost fluid weight being replaced.
• Athletes must monitor sodium intake and may have to reduce sodium to zero during the final days of cutting to facilitate water loss.
• Fight week preparation involves coming in hydrated, healthy, and not overtrained. Sodium, carbohydrates, and low-residue diets help manage water weight leading up to competition.
• Athletes can cut up to 15 pounds of water in a week, with the last portion actively removed using techniques like sauna or cardio.
• Replenishing muscle glycogen is achievable within 36 hours post-weigh-in, but restoring brain fluid may take longer.
• There is debate over the trade-offs between cutting weight and showing up closer to fight weight for physiological advantage.

Different types of athletes (02:01:48)

• Athletes exemplify excellence in various muscle-dependent sports: powerlifters excel in maximal strength, weightlifters combine strength with coordination and explosiveness, strongmen blend strength with endurance, CrossFitters balance strength with agility and cardiovascular endurance, and bodybuilders focus on aesthetics without performance requirements.
• Sprinters represent an optimized ratio of power to weight for locomotion.
• While most people will not reach the peak performance of these athletes, incorporating aspects of each discipline can be beneficial.

Training advice for a hypothetical client who’s untrained and wants to add muscle and functional strength for longevity (02:04:21)

• The client is untrained, willing to commit three hours a week to gym sessions, and aims to increase muscle and strength for practical, everyday tasks.
• A DEXA scan has revealed that their appendicular lean mass index (ALMI) is in the 40th percentile, but they aspire to be in the 75th percentile for lean mass for health benefits.
• The client is not a beginner to exercise but hasn't been active in a gym for a decade, being occupied with a job and family life instead.
• The training program should focus on hypertrophy, which will also improve strength at this stage due to the client’s low starting point.
• Even activities like steady-state cycling can enhance muscle growth in the initial six to eight weeks of training.
• Beginning with general physical fitness before targeting muscle mass is highly recommended for effectiveness.

Changes in muscle and muscular function that occur with aging (02:09:10)

• With aging, there's a loss of physical function, especially in muscular power, which declines more rapidly than muscle mass or strength.
• Loss of speed contributes significantly to the decrease in power.
• Maintaining and preserving muscle power and speed is critical for long-term physical function.
• Research shows a pronounced loss of fast-twitch fiber size and power with aging, while slow-twitch fibers remain comparatively stable regardless of exercise.
• It's essential to counteract fast-twitch fiber atrophy through targeted training as it's the primary concern for muscle deterioration with age.
• Specific training protocols are necessary to maintain fast-twitch fibers, which aren't as readily impacted by regular day-to-day activities or non-specific training as slow-twitch fibers.
• Focus on preventing atrophy in fast-twitch muscle fibers should be a priority over aspects that will improve simultaneously without targeted intervention.
• Long-term well-being requires attention to both muscle preservation, particularly fast-twitch fibers, and cardiovascular aspects such as VO2 max.

Training plan for the hypothetical client (02:15:51)

• Start with a low volume to prevent excessive soreness which can discourage further training.
• Avoid eccentric movements initially to reduce soreness.
• Focus on building essential movement patterns to prevent injuries in the long term.
• Begin with 1-3 working sets of 4 exercises, emphasizing compound movements such as goblet squats and basic overhead presses.
• Spend 30 minutes ensuring proper form, spine alignment, and breathing, without tracking progression.
• Goal is to optimize movement patterns and learn skills of exercise without causing injury.

Progressing the training plan after six months [N/A]

• Introduce power and speed exercises at the beginning of each workout.
• Include box jumps focusing on landing on the box to minimize eccentric loading.
• Address tissue tolerance, i.e., ability to land and absorb impact, for fall prevention.
• Training for speed and eccentric strength is crucial to prevent falls and injuries in later life.
• Incorporate medicine ball throws, bounds, skips, and plyometrics while controlling volume.
• Include sprints at 70% effort but with controlled progression and full recovery between sets.
• Vary workouts with enjoyable activities like basketball, racquetball, or badminton, targeting multiple movement planes.
• Ensure full-body workouts each session to maintain consistency despite potential schedule disruptions.
• Alternate among different rep ranges (heavy loads with fewer reps, higher reps with lighter weights, isometrics) across the workout days.
• All approaches aim to ensure hypertrophy and functional strength necessary for daily activities and prevention of age-related decline.

What drives muscle hypertrophy? (02:30:51)

• Isometric exercises, where muscles contract without movement, can elicit the same hypertrophy response as movement-based isotonic exercises.
• The stimuli that drive muscle hypertrophy are varied and can result from different types of training and progressions (more volume, reps, weight, or range of motion).
• Muscles typically respond best to being put under the most significant stretch, which sends a strong growth signal and should be considered when choosing the range of motion for isometric exercises.
• The optimal position for training a muscle is variable. It can depend on whether the muscle crosses a single joint or multiple joints, and each case requires different positioning.
• Training in specific ranges of motion can be sport-specific or tailored to avoid injury. For powerlifters, training in a particular range that matches competition lifts may be beneficial.
• Isometrics require precision to ensure they target the desired muscle and range without causing injury or compromising recovery.
• Overall, muscle growth is multidimensional, and while there is no one-size-fits-all answer to the best type of hypertrophy training, as long as sufficient overload is provided, muscles will generally adapt and grow.

How to properly incorporate isometric exercises into a workout (02:38:27)

• Isometric exercises, like an isometric squat, are performed by pushing against an immovable object, such as a loaded barbell fixed below safety pins in a rack.
• These exercises have the advantage of stability, as there are fewer moving parts, reducing the risk of getting out of position.
• Isometrics can provide intensive stimuli with low risk and focus on specific positions within the strength curve.
• Using bands or chains can challenge stronger areas without being limited by weaker positions.
• One can also do isometric exercises in these weak positions to improve without needing to move heavy loads.
• For exercises like the Romanian Deadlift (RDL), the bar is set in a rack at a comfortable height and lifted against without actual movement, which can activate muscles like the glutes without worrying about balance or back safety.
• The isometric hold duration can vary from three seconds to extended periods, like a five-minute squat hold, offering a neurological challenge.
• Isometrics can be part of a workout routine and can include various exercises like planks and hip extensions.
• It's also possible to train in a full squat position, aiming to maintain good form rather than simply holding the position until fatigue sets in.
• The goal is not to hold the position as long as possible, but to hold it correctly, with failure determined by form breaking down rather than giving up due to fatigue.

Additional training tips: movement patterns, how to finish a workout, and more (02:46:38)

• Incorporate multiple planes of movement in workouts, including frontal, sagittal, and transverse, to ensure diverse and functional physical development.
• Utilize a mix of unilateral and bilateral exercises, such as single-leg presses, step-ups, and split squats, to avoid overreliance on dual-legged or barbell-centric moves.
• Mix up equipment usage, selecting from barbells, dumbbells, kettlebells, and machines, to provide variety and prevent technical difficulties, particularly for less experienced individuals.
• A suggested training approach is to allocate 60% of workout time to current abilities, 20% to long-term development, and 20% to exercises that are enjoyable.
• Finish each session with exercises that target personal challenges or goals, like a tricep blast for someone who wants to improve their triceps.
• Listen to clients' goals and incorporate their personal pain points into the routine, ensuring they feel heard and their objectives are being worked on.
• Engage clients with sessions they look forward to, such as a 'gun show' day focusing on biceps and triceps, to maintain their motivation and attendance.