Skeletal Muscle Hypertrophy: Skeletal Muscle Hypertrophy: an overview an overview Michael H. Stone Michael H. Stone Center for Excellence for Sport Science Center for Excellence for Sport Science and Coach Education and Coach Education KLSS KLSS East Tennessee State University East Tennessee State University Definitions: Definitions: Hypertrophy – increased cross‐sectional area and mass of the skeletal muscle Hyperplasia – increase in skeletal muscle mass as a result of creating additional (new) muscle fibers or by satellite cell incorporation
Repeated stimuli of damaging fibers through regular Repeated stimuli of damaging fibers through regular resistance exercise followed by adequate recovery results in a resistance exercise followed by adequate recovery results in a net anabolic effect and protein accretion net anabolic effect and protein accretion
Carlson, B.M. the regeneration of skeletal muscle Am J Anat Carlson, B.M. the regeneration of skeletal muscle Am J Anat 137: 119137: 119‐‐150, 1973150, 1973
Muscle Tissue RemodelingMuscle Tissue Remodeling: The reorganization or renovation of existing muscle tissue. This process can either change the characteristics of the tissue or result in a dynamic equilibrium dynamic equilibrium of tissue hypertrophy/atrophy. Mechanistically, remodeling results largely from – protein turnover involving the summation of protein synthesis and protein catabolic effects.
Anabolic effects – protein synthesis
Catabolic effects – protein breakdown
Anabolic effects = Catabolic effects: dynamic equilibrium – no hypertrophy or atrophy
Type I: synthesis and degradationsynthesis and degradation
Type II synthesis and degradation
Type II fibers tend to respond at a faster rate than Type I
MUSCLE STRUCTURAL ADAPTATIONS TO RTMUSCLE STRUCTURAL ADAPTATIONS TO RT
Hakkinen et al. Hakkinen et al. J Gerontol A Biol Sci Med Sci J Gerontol A Biol Sci Med Sci 53(6): B41553(6): B415‐‐23, 199823, 1998
Deschenes, M.R. et al. Endurance and resistance exercise inducesDeschenes, M.R. et al. Endurance and resistance exercise induces muscle fibre type muscle fibre type specific respsonses in androgen binding capacity. J. Steroid Biospecific respsonses in androgen binding capacity. J. Steroid Biochem Mol. Bio chem Mol. Bio 50:17550:175‐‐179, 1994179, 1994
TASK SPECIFIC HYPERTROPHYTASK SPECIFIC HYPERTROPHY
Regional Hypertrophy: Regional Hypertrophy:
Abe, T. et al. Abe, T. et al. Br J Sports Med Br J Sports Med 3737‐‐543543‐‐545, 2003.545, 2003.
Contraction Type Advantages Contraction Type Advantages
Eccentric or CON/ECC can produce greater hypertrophy than concenEccentric or CON/ECC can produce greater hypertrophy than concentric tric alone. alone.
Walker et al. Walker et al. Arch Phys Med Rehabil Arch Phys Med Rehabil 79: 139179: 1391‐‐1398, 19981398, 1998
Eccentric Accentuated training Eccentric Accentuated training maymay produced greater hypertrophy and produced greater hypertrophy and a faster stronger muscle than traditional training a faster stronger muscle than traditional training
Friedman B. et al. Friedman B. et al. Acta Physiol Scand Acta Physiol Scand 182: 77182: 77‐‐88, 200488, 2004Ojasto T. and Hakkinen K. Ojasto T. and Hakkinen K. JSCRJSCR 23:94623:946‐‐953, 2009953, 2009
Repeated Contractions Repeated Contractions –– increased increased metabolism metabolism –– decreased ATP decreased ATP availabilityavailability
Mechanical StressMechanical Stress
Initial damage Initial damage –– Z disk Z disk streaming and myofibrillar streaming and myofibrillar disruption disruption –– plasma membrane plasma membrane disruptiondisruption
Modified from Laplante and Sabatini, 2008; Nadar, 2006
Strong relation between Strong relation between mTORC1 activation, increased mTORC1 activation, increased FFM and strength:FFM and strength:
Terzis G. et al. resistance exercise‐induced increase in muscle mass correlates with p70S6 kinase phosphoylation in human subjects. Eu J Appl Physiol 102:145‐152, 2007.
After 14 wks of resistance After 14 wks of resistance training in young males (n = 6) training in young males (n = 6) the phosphorylation the phosphorylation activation) of p70activation) of p70S6k S6k was was strongly correlated with strongly correlated with increased FFMincreased FFMwbwb (r = 0.89), (r = 0.89), FFMFFMleg leg (r = 0.81), 1RM squat (r = 0.81), 1RM squat (r = 0.84) and Type II X(r = 0.84) and Type II X‐‐sec sec area ( r = 0.82). area ( r = 0.82).
Exercise = simultaneous activation of different ICS pathwaysExercise = simultaneous activation of different ICS pathways
Increased Protein Synthesis Increased Protein Synthesis –– muscle muscle and connective tissue remodelingand connective tissue remodeling
Inhibits Phosphorylation (activation) of mTORC1
TSC1/2TSC1/2
Nader, G. Concurrent strength and Nader, G. Concurrent strength and endurance training From molecules to man endurance training From molecules to man Med Sci Sports Exerc Med Sci Sports Exerc 38: 196538: 1965‐‐1970, 20061970, 2006
volume increase volume increase (independent of (independent of exercise type) exercise type) ––calcineurin calcineurin –– low low [glycogen][glycogen]
myostatin(‐)
Mitochondrial Mitochondrial biogenesis, shift in biogenesis, shift in MHC toward MHC toward MHC1, etc. MHC1, etc.
Myostatin (growth differentiation factor 8: GDF‐8): secreted as a TGF beta protein family member that inhibits muscle differentiation and growth.
Myostatin : produced primarily in skeletal muscle cells, circulates in the blood and acts on muscle tissue by binding a cell‐bound receptor (activin type II receptor) and inhibiting the action of specific growth factors and mitogens mitogens such as IGF1
Animals lacking myostatin (or animals treated with substances such as follistatin that block the binding of myostatin to its receptor) have substantially larger muscles.
Significant relationship in whippets between a myostatin mutation and racing performance. Whippets that are heterozygous for a 2 base pair deletion in myostatin are significantly over‐represented in the top racing classes.
The mutation resulted in a truncated myostatin mRNA, apparently resulting in an inactive form of myostatin.
Mosher DS, Quignon P, Bustamante CD, Sutter NB, Mellersh CS, Parker HG, Ostrander EA . "A mutation in the myostatin gene increases muscle mass and enhances racing performance in heterozygote dogs". PLoS Genet. 3(5): e79, 2007.
Photographs of child at 7 months, 6 days
a. Photo
b. Ultrasonagrams
c. Morphometric analysis
d. Hereditary tree
Muscle DevelopmentMuscle Development
growthgrowth
(-)
Myostatin
(-)Androgens
+
Most studies (not all): Resistance Exercise/Training Most studies (not all): Resistance Exercise/Training appearsappears to to downdown‐‐regulate myostatin expressionregulate myostatin expression
Exercise Exercise
Kvorning, T. et al. Suppression of testosterone does not blunt mKvorning, T. et al. Suppression of testosterone does not blunt mRNA expression of myoD, RNA expression of myoD, myogenin, IGF, myostatin or androgen receptor post strength traimyogenin, IGF, myostatin or androgen receptor post strength training in humans. J Physiol 578(pt ning in humans. J Physiol 578(pt 2): 5792): 579‐‐593, 2006 593, 2006
Training Training JeongJeong‐‐su, K. et al. su, K. et al. Endocrinology and MetabolismEndocrinology and Metabolism 288: E1110288: E1110‐‐E1119, 2005E1119, 2005
Walker et al. Walker et al. Medicine and Science in Sports and Exercise 36: 787Medicine and Science in Sports and Exercise 36: 787‐‐793, 2004793, 2004
Roth et al. Roth et al. Experimental Biology and MedicineExperimental Biology and Medicine 228: 706228: 706‐‐709, 2003709, 2003
Saremi A. et al. Saremi A. et al. Molecular Cell EndocrinologyMolecular Cell Endocrinology. 2010 Apr 12;317(1. 2010 Apr 12;317(1‐‐2):252):25‐‐30, 2009 (may interact with creatine)30, 2009 (may interact with creatine)
Hulmii, J.J. Hulmii, J.J. Resistance exercise with whey protein ingestion affects mTOR sigResistance exercise with whey protein ingestion affects mTOR signaling pathway and myostatin in naling pathway and myostatin in men.men. J Appl PhysiolJ Appl Physiol. 106(5):1720. 106(5):1720‐‐9, 2009. 9, 2009.
Review: Wackerhage H. and Ratkevicius A. Signal transduction pathways that regulate muscle growth. Essays Biochem. 44:99‐108, 2008.
ThereforeTherefore‐‐ one aspect of resistance training induced hypertrophy is a one aspect of resistance training induced hypertrophy is a reduction in the limits placed on muscle growthreduction in the limits placed on muscle growth
Endocrine InfluencesEndocrine Influences
Acute vs ChronicAcute vs Chronic
Direct Effects of HormonesDirect Effects of Hormones: :
Androgens Androgens & Estrogens& Estrogensreceptors for both in skeletal myofibers receptors for both in skeletal myofibers possiblepossible direct effects to increase muscle protein synthesis direct effects to increase muscle protein synthesis Androgens have been associated with increased satellite cell numAndrogens have been associated with increased satellite cell number and incorporationber and incorporation
InsulinInsulinMyofibersMyofibers have more insulin receptors than IGFhave more insulin receptors than IGF1 1 receptors thus insulin is necessary for myofiber hypertrophy receptors thus insulin is necessary for myofiber hypertrophy this hypertrophy is necessary to store protein in muscle this hypertrophy is necessary to store protein in muscle
Resting muscleResting muscle needs insulin to increase in size (i.e. increase nutrient uptakneeds insulin to increase in size (i.e. increase nutrient uptake for storage and production of e for storage and production of contractile protein secretion); thus following a meal, when insucontractile protein secretion); thus following a meal, when insulin is secreted, excess nutrients can be stored in lin is secreted, excess nutrients can be stored in muscle. If insulin is low, muscles atrophy and protein stores armuscle. If insulin is low, muscles atrophy and protein stores are mobilized. e mobilized. Contracting muscleContracting muscle does not need insulin for glucose uptake; thus nutrients in thedoes not need insulin for glucose uptake; thus nutrients in the circulation can enter muscle to circulation can enter muscle to supply energy for contraction without eating a meal and getting supply energy for contraction without eating a meal and getting the subsequent rise in circulating insulin the subsequent rise in circulating insulin
Growth Hormone (GH, somatotropin)Growth Hormone (GH, somatotropin)No direct effects. There is no evidence of GH receptors on skeleNo direct effects. There is no evidence of GH receptors on skeletal muscle. tal muscle.
Thyroid HormonesThyroid Hormonesthyroid hormones required for control of myofiber thyroid hormones required for control of myofiber maturationmaturation : during development they increase myofiber size : during development they increase myofiber size and affect anaerobic metabolism and affect anaerobic metabolism
GlucocorticoidsGlucocorticoidsexcess is catabolic in muscle (myofibers) excess is catabolic in muscle (myofibers) excess decreases protein synthesis excess decreases protein synthesis excess increases protein degradation excess increases protein degradation
Acute Endocrine influences:Hypothesis: postHypothesis: post‐‐exercise (lasting 10 exercise (lasting 10 –– 40 min) endocrine responses 40 min) endocrine responses influence hypertrophy (recurrent mechanical stimuli + increased influence hypertrophy (recurrent mechanical stimuli + increased hormone hormone concentrations such as hGH and T result in accentuated hypertropconcentrations such as hGH and T result in accentuated hypertrophy hy response that summates over time) response that summates over time) ––large muscle mass exercise elevates hormones to a greater extentlarge muscle mass exercise elevates hormones to a greater extent than than small muscle mass exercisesmall muscle mass exercise
Evidence: only four studies found :Evidence: only four studies found :
Hansen S., Kvorning T., Kjaer M., Sjogaard G. The effect of short‐term strength training on human skeletal muscle: the importance of physiologically elevated hormone levels. Scand J Med Sci Sports 11: 347–354, 2001 – incorporation of leg work (HH) prior to arm work (LH) enhanced arm strength gains (hypertrophy not directly measured)
Ahtiainen J.P et al. Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength‐trained and untrained men. Eur J Appl Physiol 89:555‐63, 2003. Mean acute responses across 21 weeks of training correlated with isometric strength and CSA (however, basal and mean acute were strongly correlated)
Beaven CM. et al. Significant strength gains observed in Rugby players after specific resistance exercise protocols based on individual salivary testosterone responses, JSCR 22: 419‐425, 2008. Long‐term effect – assumption was that responses made difference – no direct evidence – no measure of LBM/CSA alterations – changes in strength were not large – problems?problems?
Spiering, B.A. Kraemer, , W.J., Vingren, J.L., Ratamess, N.A., Anderson, J.M., Armstrong, L.E., Nindl, B.C., Volek, J.S., Häkkinen H. and Maresh, C.M.. Elevated endogenous testosterone concentrations potentiate muscle androgen receptor responses to resistance exercise . J Steroid Biochemi Mol Biol 114: 195‐199, 2009 . ‐ incorporation of leg work prior to arm work enhanced androgen receptor content (hypertrophy not directly measured)
Acute Endocrine influences:
Hypothesis: postHypothesis: post‐‐exercise endocrine responses influence hypertrophy (recurrent exercise endocrine responses influence hypertrophy (recurrent mechanical stimuli + increased hormone concentrations such as hGmechanical stimuli + increased hormone concentrations such as hGH and T result in H and T result in accentuated hypertrophy response that summates over time) accentuated hypertrophy response that summates over time)
Evidence against:Evidence against:
1.1.Hypophysectimized, castrated animals can still show considerableHypophysectimized, castrated animals can still show considerable hypertrophy when trained hypertrophy when trained –– however however –– adding T or T +GH adding T or T +GH chronically does increase effect. chronically does increase effect.
2.2.ShortShort‐‐term higher intensity aerobic exercise can result in marked incrterm higher intensity aerobic exercise can result in marked increases in anabolic hormones eases in anabolic hormones ––however, aerobic exercise however, aerobic exercise results in little or no hypertrophy results in little or no hypertrophy
3.3.Increased hormone (especially T) concentrations can be higher asIncreased hormone (especially T) concentrations can be higher as a result of circadian rhythms than posta result of circadian rhythms than post‐‐exercise values. (Training exercise values. (Training time may influence this)time may influence this)
McMillan, J. et al. 20McMillan, J. et al. 20‐‐hour physiological responses to a single weighthour physiological responses to a single weight‐‐training session training session J Strength Cond ResJ Strength Cond Res 7:97:9‐‐21, 199321, 1993
Bird, S.P. and Tarpening K.M. Influence of circadian time structBird, S.P. and Tarpening K.M. Influence of circadian time structure on acute responses to a single bout of heavy ure on acute responses to a single bout of heavy resistance exercise in weightresistance exercise in weight‐‐trained men. Chronobiology International 21:131trained men. Chronobiology International 21:131‐‐146, 2004146, 2004
4. 4. Women have approximately 10 % of the testosterone concentrationWomen have approximately 10 % of the testosterone concentration of men but show the same of men but show the same ““relativerelative””hypertrophy compared with men.hypertrophy compared with men.
Cureton, K. J., Collins M.A. HILL D.W. and McElhannon F. M. . Muscle hypertrophy in men and women. Med. Sci. Sports. Exerc, Vol. 20, No. 4, pp. 338‐344, 1988.
O'Hagan F.T., Sale D.G., MacDougall .JD., Garner S.H. Response to resistance training in young women and men. Int J Sports Med. 16:314‐21, 1995.
Acute Endocrine influences:
Hypothesis: postHypothesis: post‐‐exercise endocrine responses influence hypertrophy (recurrent meexercise endocrine responses influence hypertrophy (recurrent mechanical chanical stimuli + increased hormone concentrations such as hGH and T resstimuli + increased hormone concentrations such as hGH and T result in accentuated ult in accentuated hypertrophy response that summates over time) hypertrophy response that summates over time)
Evidence against:Evidence against:
3.3.No correlation or evidence of hypertrophy (or strength) enhancemNo correlation or evidence of hypertrophy (or strength) enhancement as a result of acute ent as a result of acute hormone responses:hormone responses:
Wilkinson, S.B. Hypertrophy with unilateral resistance exercise Wilkinson, S.B. Hypertrophy with unilateral resistance exercise occurs without increases in endogenous anabolic hormone occurs without increases in endogenous anabolic hormone concentration concentration Eur J Appl Physiol Eur J Appl Physiol 98:54698:546‐‐555, 2006. 555, 2006. Hypertrophy occurred only in the trained leg and occurred indepeHypertrophy occurred only in the trained leg and occurred independently of hormone ndently of hormone elevationelevation
Kvorning, T. et al. Suppression of testosterone does not blunt mKvorning, T. et al. Suppression of testosterone does not blunt mRNA expression of myoD, myogenin, IGF, myostatin or RNA expression of myoD, myogenin, IGF, myostatin or androgen receptor post strength training in humans. androgen receptor post strength training in humans. J Physiol J Physiol 578(pt 2): 579578(pt 2): 579‐‐593, 2006 . 593, 2006 . ‐‐ treatment with goserelin causes lower T treatment with goserelin causes lower T ‐‐placebo showed increased postplacebo showed increased post‐‐ex T, goserelin group showed decreased T responses; no differenex T, goserelin group showed decreased T responses; no differences between groups in mRNA expression, ces between groups in mRNA expression, myoD, myogenin, IGF, myostatin or androgen receptor post strengtmyoD, myogenin, IGF, myostatin or androgen receptor post strength training in humansh training in humans
West, D.W., et al. Resistance exerciseWest, D.W., et al. Resistance exercise‐‐induced increases in putative anabolic hormones do not enhance minduced increases in putative anabolic hormones do not enhance muscle protein uscle protein synthesis or intracellular signaling in young men. synthesis or intracellular signaling in young men. J Physiol. J Physiol. 587(pt2): 5239587(pt2): 5239‐‐5247, 2009. 5247, 2009. markers of protein synthesis and markers of mTOR markers of protein synthesis and markers of mTOR were not different between arm only (LH) and arm + leg (HH) resiwere not different between arm only (LH) and arm + leg (HH) resistance exercise. stance exercise.
West, D.W., et al. Elevations in ostensibly anabolic hormones wWest, D.W., et al. Elevations in ostensibly anabolic hormones with resistance exercise enhance neither training ith resistance exercise enhance neither training ––induces induces muscle hypertrophy nor strength of the elbow flexors muscle hypertrophy nor strength of the elbow flexors J Appl Physol J Appl Physol 108: 60108: 60‐‐67, 2009. 67, 2009. XX‐‐sectional area was not different between arm only sectional area was not different between arm only and arm + leg resistance exercise. and arm + leg resistance exercise.
Acute Endocrine influences:
Hypothesis: postHypothesis: post‐‐exercise endocrine responses influence hypertrophy exercise endocrine responses influence hypertrophy (recurrent mechanical stimuli + increased hormone concentrations(recurrent mechanical stimuli + increased hormone concentrations such as such as hGH and T result in accentuated hypertrophy response that summathGH and T result in accentuated hypertrophy response that summates over es over time) time)
Evidence against:Evidence against:
4. Disconnect between post4. Disconnect between post‐‐exercise hormone concentrations and exercise hormone concentrations and hypertrophy response hypertrophy response –– hormone responses to absolute (and likely hormone responses to absolute (and likely relative) loads tend to decrease after trainingrelative) loads tend to decrease after training
[ Hormon
e]Hormon
e]
Time
Hypertrophy
Hypertrophy
Buresh R., Berg K. and French J. The effect of resistive exercise rest intervals on hormonal response, strength and hypertrophy with training JSCR 23:62‐71, 2009
MUSCLE REMODELINGMUSCLE REMODELING
EXERCISE STIMULUSEXERCISE STIMULUS
DAMAGE??/TENSION??/ METABOLISM
IMMUNE SYSTEM IMMUNE SYSTEM RESPONSERESPONSE AUTOCRINE/PARACRINEAUTOCRINE/PARACRINE
RESPONSERESPONSE
ENDOCRINEENDOCRINERESPONSERESPONSE
HYPERTROPHYHYPERTROPHY
++ MINOR MINOR EFFECTEFFECT
Acute Effects of Post Exercise Hormone ResponsesAcute Effects of Post Exercise Hormone Responses
Metabolism Metabolism
Chronic Endocrine Influences
1.No contest – anabolic steroid research2.Genetics and resting LH, FSH and testosterone concentrations
Harris J.A. et al. The heritability of testosterone: a study of Harris J.A. et al. The heritability of testosterone: a study of Dutch Dutch adolescent twins and their parents. adolescent twins and their parents. Behav GenetBehav Genet 28:16528:165‐‐171 , 1998171 , 1998
Hoekstra R.A. et al. Hoekstra R.A. et al. Heritability of testosterone levels in 12Heritability of testosterone levels in 12‐‐yearyear‐‐old twins old twins and its relation to pubertal development. and its relation to pubertal development. Twin Res Hum GenetTwin Res Hum Genet. 9(4):558. 9(4):558‐‐65, 200665, 2006
Kuijpers E.A. et al. Kuijpers E.A. et al. Heritability of reproductive hormones in adult male Heritability of reproductive hormones in adult male twins. twins. Hum Reprod.Hum Reprod.:2153:2153‐‐9, 20079, 2007
Bogart, G. et al. Heritability of blood concentrations of sexBogart, G. et al. Heritability of blood concentrations of sex‐‐steroids in steroids in relation to body composition in young adult male siblings. relation to body composition in young adult male siblings. Clin Endocrinol Clin Endocrinol (Oxf). (Oxf). 69:12969:129‐‐35. 200835. 2008
3. Testosterone 3. Testosterone –– Heritability + TrainingHeritability + Training
TESTOSTERONE: PRIMARY ANDROGENTESTOSTERONE: PRIMARY ANDROGENPRIMARY AND SECONDARY SEX CHARACTERISTICS
METABOLIC EFFECTSMETABOLIC EFFECTS
• PROMOTES PROTEIN SYNTHESIS
• ANTI‐CATABOLIC EFFECTS
ANTAGONISES GLUCOCORTICOIDS (DISPLACES CORTISOL FROM RECEPTOR)
INHIBITION OF MUSCLE GLYCOGEN CATABOLISM
• CAN DECREASE FAT MASS
EFFECTS ON NERVE TISSUEEFFECTS ON NERVE TISSUE
• INCREASED CNS NEURON EXCITABILITY (?)
• INCREASED ACH RECEPTOR DENSITY AND SIZE OF MEP IN PERIPHERAL MUSCLES
• MAINTANANCE OF DOPAMINERGIC CNS NEURONS
ENHANCES MAXIMUM STRENGTH AND EXPLOSIVNESSENHANCES MAXIMUM STRENGTH AND EXPLOSIVNESS
COMPENSATES FOR MUSCULAR FATIGUECOMPENSATES FOR MUSCULAR FATIGUE
• ENHANCED EFFICIENCY OF Ca++ DISPOSITION (primarily Type II fibers)
Bhasin, S. et al. The Effects of Supraphysiologic Doses of Testosterone on Muscle Size and Strength in Normal Men, N Eng J Med, 335: 1‐7, 1996
Herbst K.L. and Bhasin, S. Testosterone action on skeletal muscle. Current Opin Clin Nutr Meteb Care
7(3): 271‐277, 2004
Bialek,M. et al. Neuroprotective role of testosterone in the nervous system. Pol J Pharmacol 56: 509—518, 2004
Barkley, M.S. and Goldman, B.D. Horm Behav 9:32‐48, 1977 (animals)
Olweus, D. et al. Psychosom Med 50:261‐272, 1988 (humans)
It may be possible that T promotes aggressiveness or some type of centrally mediated drive promoting strength, power and explosiveness in power events (Wright and Stone 1993, Viru and Viru 2005).
Training + higher resting testosterone (chronically elevated) Training + higher resting testosterone (chronically elevated) = less fat, = less fat, greater hypertrophygreater hypertrophy, strength, explosiveness, , strength, explosiveness, power power
Cardinale, M. and Stone, M.H. Is testosterone influencing explosive performance? Journal of Strength and Conditioning Research 20: 103‐107, 2006.
Arslanian S. and Suprasongsin C. Testosterone treatment in adolescents with delayed puberty: changes in body composition, protein, fat, and glucose metabolism. J Clin Endocrinol Metab. 82:3213‐20, 1997
Reviews: Reviews:
Tipton K.D. and Wolfe R.R. Exercise, Protein metabolism and muscTipton K.D. and Wolfe R.R. Exercise, Protein metabolism and muscle growth. le growth. Int J Sport Int J Sport Nutr Exerc Metab Nutr Exerc Metab 11: 10911: 109‐‐132, 2001132, 2001
BBhasin, S. et al. Proof of the effect of testosterone on skeletal muscle. J EndocrinolJ Endocrinol 170: 27‐38, 2001.
Matlock, A.G. et al. Androgens and skeletal muscle. Cellscience Reviews 2: 9‐16, 2005
Hakkinen K. et al. Hakkinen K. et al. J Appl PhysiolJ Appl Physiol 65:240665:2406‐‐2412, 19882412, 1988
Kraemer W. et al. Kraemer W. et al. Med Sci Sports ExercMed Sci Sports Exerc 20: S15220: S152‐‐S157, 1988.S157, 1988.
Niklas B..J. et al. Niklas B..J. et al. Int J Sports MedInt J Sports Med 16:44516:445‐‐450, 1995 (mid age men)450, 1995 (mid age men)
Warren, B. et. al. Warren, B. et. al. Int J Sports MedInt J Sports Med 13: 37213: 372‐‐376, 1992 (1 K 376, 1992 (1 K ‐‐ Junior WL)Junior WL)
INCREASEDINCREASED
Staron et al. J Appl Physiol 76:1247Staron et al. J Appl Physiol 76:1247‐‐1255, 1994 (4 weeks)1255, 1994 (4 weeks)
Johnson, C. et al. Johnson, C. et al. J Sports Med Phys FitJ Sports Med Phys Fit, , 2323: 39: 39‐‐41, 1983. (mid age men)41, 1983. (mid age men)
Hakkinen K. et al. Hakkinen K. et al. J Appl PhysiolJ Appl Physiol 65:240665:2406‐‐2412, 1988 (weightlifters > 2 y )2412, 1988 (weightlifters > 2 y )
Stone, M. H. and Fry, A.C. Stone, M. H. and Fry, A.C. Overtraining in SportOvertraining in Sport, pp 87, pp 87‐‐105, 1998 (junior WL pre105, 1998 (junior WL pre‐‐ex)ex)
Tsolakis, C. et al. J Appl Sports Sci Res 14:399Tsolakis, C. et al. J Appl Sports Sci Res 14:399‐‐404, 2000 (boys)404, 2000 (boys)
Marx, J. et al. Marx, J. et al. Med Sci Sports ExercMed Sci Sports Exerc 33:63533:635‐‐643, 2001 (women)643, 2001 (women)
TRAINING INDUCED RESPONSES TO EXERCISETRAINING INDUCED RESPONSES TO EXERCISE
NO CHANGENO CHANGE
Niklas B..J. et al. Niklas B..J. et al. Int J Sports MedInt J Sports Med 16:44516:445‐‐450, 1995 (mid age men)450, 1995 (mid age men)
Tsolakis C.K et al. JSCR 18:625Tsolakis C.K et al. JSCR 18:625‐‐629, 2004 (pre629, 2004 (pre‐‐adolescent boys)adolescent boys)
INCREASEDINCREASED
Kraemer W. et al. Kraemer W. et al. Int J. Sports MedInt J. Sports Med 20:10320:103‐‐109, 1992 (junior WL > 2y)109, 1992 (junior WL > 2y)
Stone, M. H. and Fry, A.C. Stone, M. H. and Fry, A.C. Overtraining in SportOvertraining in Sport, pp 87, pp 87‐‐105, 1998 (junior WL)105, 1998 (junior WL)
Ratamess, N.A. et al. J. Steroid biochem Molec Biol 93:35Ratamess, N.A. et al. J. Steroid biochem Molec Biol 93:35‐‐42, 200542, 2005
Training induced Training induced alterations in T is alterations in T is likely to be a likely to be a function of function of fatigue/stress fatigue/stress management management ––
Free versus Bound Free versus Bound –– not all studies not all studies agree agree –– however, however, generally ratio is generally ratio is unchanged unchanged ‐‐ if if total T increase total T increase ––FT increases.FT increases.
InsulinInsulin
In mammals, insulin is a protein synthesized in the the islets of Langerhans of the pancreas (β‐cells) and is released when any of several stimuli are detected, including food (carbohydrate > protein, >>>fat) and CNS input. Insulin initiates a signal transduction, which has the effect of increasing glucose, amino acid uptake and storage. Insulin is a Insulin is a strong anabolic hormonestrong anabolic hormone.
Insulin can decrease as a result of a training session
McMillan, J. et al. 20-hour physiological responses to a single weight-training session J Strength Cond Res 7:9-21, 1993
Supplementation (carboSupplementation (carbo--protein timed) or a meal protein timed) or a meal increases/maintains insulin concentrations and increases/maintains insulin concentrations and promotes muscle growth (hypertrophy) promotes muscle growth (hypertrophy)
Mitogens
A mitogen is usually some form of a polypeptide or protein.that can trigger signal transduction pathways in which a mitogen‐activated protein kinase is involved, leading to mitosis and increased growth in muscle tissue.
Examples:
Insulin‐like Growth factor‐1 (IGF‐1)
Mechano‐growth factor (MGF)
Fibroblast Growth factor (FGF) – directly responds to injury of muscle tissue
Hepatocyte Growth factor (HGF)
Adams, G.R., and F. Haddad. The relationships among IGF‐1, DNA content, and protein accumulation during skeletal muscle hypertrophy. Journal of Applied Physiology 81(6): 2509‐2516, 1996.
Fiatarone Singh, M. A., W. Ding, T. J. Manfredi, et al. Insulin‐like growth factor I in skeletal muscle after weight‐lifting exercise in frail elders. American Journal of Physiology 277 (Endocrinology Metabolism 40): E135‐E143, 1999.
Yamada, S., N. Buffinger, J. Dimario, et al. Fibroblast Growth Factor is stored in fiber extracellular matrix and plays a role in regulating muscle hypertrophy. Medicine and Science in Sports and Exercise 21(5): S173‐180, 1989.
Example:
••IGFIGF‐‐11: 70 amino acids in a single chain with three intramolecular disulfide bridges(7649 daltons)..
••Produced primarily by the liver as an Produced primarily by the liver as an endocrine hormone as well as in target endocrine hormone as well as in target tissues as part of the paracrine/autocrine tissues as part of the paracrine/autocrine functionfunction.
•Production is stimulated by growth hormone (and testosterone) and can be impeded by undernutrition, low glycogen concentrations, receptor insensitivity, lack of growth hormone receptors, or failures of the downstream signaling pathway
•In rat experiments the amount of IGF‐1 mRNA in the liver was positively associated with dietary casein and negatively associated with a protein free diet.
Muscle Catabolism and Atrophy Muscle Catabolism and Atrophy
Glucocorticoids (cortisol) Glucocorticoids (cortisol) block the phosphorylation block the phosphorylation (activation) of Akt thus (activation) of Akt thus mTOR is less activated and mTOR is less activated and the FOXO proteins stimulate the FOXO proteins stimulate protein catabolism. protein catabolism.
Cortisol response tends to Cortisol response tends to decrease at the same loading decrease at the same loading postpost‐‐training training –– smaller smaller influence? influence?
Cortisol release and Cortisol release and accumulation is blunted by accumulation is blunted by carbohydrate intake.carbohydrate intake.
Testosterone:Cortisol Ratio Testosterone:Cortisol Ratio
TESTOSTERONE:CORTISOL RATIO (T : C)TESTOSTERONE:CORTISOL RATIO (T : C)
••INDEX OF: INDEX OF: ““ANABOLIC STATUSANABOLIC STATUS”” –– T:C related to: T:C related to:
••LBM, FAT MASS, MAXIMUM STRENGTHLBM, FAT MASS, MAXIMUM STRENGTH, RFD, POWER , RFD, POWER Hakkinen, K. et al. Hakkinen, K. et al. Eur J Appl PhysiolEur J Appl Physiol 53:28753:287‐‐293, 1985293, 1985
Hakkinen, K. et al. Hakkinen, K. et al. Int J Sports MedInt J Sports Med 11:9111:91‐‐98, 199098, 1990
Hakkinen K. et al. Hakkinen K. et al. Electromyogr Clin NeuorphysiolElectromyogr Clin Neuorphysiol 31:3531:35‐‐42, 199042, 1990
Fry, A.C. et Fry, A.C. et al. al. J Strength Cond ResJ Strength Cond Res 14:33814:338‐‐343, 2000343, 2000
••INDEX OF OVERREACHING VERSUS OVERTRAININGINDEX OF OVERREACHING VERSUS OVERTRAINING
Adlercreutz, H. et al. Adlercreutz, H. et al. Int J Sports MedInt J Sports Med 7:27S7:27S‐‐28S, 108628S, 1086
Differential effect work post exercise for T:C?
High exercise intensity low volume:‐ no effect or slight increase
Fry et al. Pituitary‐adrenal‐gonadal responses to high‐intensity resistance exercise overtraining. J Apply Physiol 85: 2352‐2359, 1998
Higher exercise volume produces greater effects on individual hormone concentrations ‐ but T:C usually no effect
Stone, M. H. and Fry, A.C. Overtraining in Sport, pp 87Stone, M. H. and Fry, A.C. Overtraining in Sport, pp 87‐‐105, 1998105, 1998
Migiano M.J. et al. Endocrine response patterns to acute unilateMigiano M.J. et al. Endocrine response patterns to acute unilateral and bilateral resistance exercise in men. JSCR ral and bilateral resistance exercise in men. JSCR 24: 12824: 128‐‐134, 2010. 134, 2010.
Higher reps/set: Effect may be independent of total mechanical work performed
McCaulley G.O. et al. Acute hormonal and neuromuscular responses to hypertrophy, strength or power type resistance exercise. Eur J Appl Pjysiol 105: 695‐704, 2009.
Training Effects on the T:CTraining Effects on the T:C
Chronic [Resting]alterations: more influenced by volume compared to intensity:
Stone, M. H. and Fry, A.C. Stone, M. H. and Fry, A.C. Overtraining in SportOvertraining in Sport, pp 87, pp 87‐‐105, 1998105, 1998
Fry et al. Pituitary‐adrenal‐gonadal responses to high‐intensity resistance exercise overtraining. J Apply Physiol 85: 2352‐2359, 1998
Haff G.G. et al. ForceHaff G.G. et al. Force‐‐time curve characteristics and hormonal alterations time curve characteristics and hormonal alterations during and elevenduring and eleven‐‐week training period in elite women weightlifters. week training period in elite women weightlifters. JSCR JSCR 22: 43322: 433‐‐436, 2008436, 2008
Men
R2 = 0.8857
R2 = 1
05000
1000015000200002500030000350004000045000
23-S
ep7-O
ct
21-O
ct4-N
ov
18-N
ov2-D
ec
0.00
10.00
20.00
30.00
40.00
50.00
60.00
VLT:CPoly. (VL)Poly. (T:C)
Hormones: T:C Ratio – T and C alterations
Men
0
500010000
1500020000
2500030000
3500040000
45000
23-Sep
7-Oct
21-Oct
4-Nov
18-Nov
2-Dec
0.00
10.00
20.00
30.00
40.00
50.00
60.00
VLT:C
MEN: TI V T:C
R2 = 1
R2 = 0.7689
0
20
40
60
1 2 3 4 5 6 7 8 9 10 11859095100105110
T:CTIPoly. (T:C)Poly. (TI)
MEN: TI V T:C
0
20
40
60
1 2 3 4 5 6 7 8 9 10 11859095100105110
T:CTI
Resting Hormones: T:C ratio – Primarily C alterations
Women
R2 = 0.9427
R2 = 0.9195
05000
10000150002000025000300003500040000
23-Sep
7-Oct
21-O
ct4-N
ov
18-Nov
2-Dec
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
VLT:CPoly. (VL)Poly. (T:C)
Women
05000
10000150002000025000300003500040000
23-Sep
7-Oct
21-O
ct4-N
ov
18-Nov
2-Dec
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
VLT:C
WOMEN: TI V T:C
R2 = 1
R2 = 0.32310
0.5
1
1.5
1 2 3 4 5 6 7 8 9 10 116570758085
T:CTIPoly. (T:C)Poly. (TI)
WOMEN: TI V T:C
0
0.5
1
1.5
1 2 3 4 5 6 7 8 9 10 116570758085
T:CTI
Primary mediating aspect of hypertrophy appears to be autocrine Primary mediating aspect of hypertrophy appears to be autocrine and and paracrine mechanisms resulting in the production of growth promoparacrine mechanisms resulting in the production of growth promoting ting ““mitogensmitogens”” which trigger intrawhich trigger intra‐‐cellular signaling:cellular signaling:
The influence of the endocrine system is likely secondary to The influence of the endocrine system is likely secondary to that of the immune response and the paracrine and autocrine that of the immune response and the paracrine and autocrine systemssystems
Bickel, C.S et al. 1998 Bickel, C.S et al. 1998 Journal of Applied PhysiologyJournal of Applied Physiology 94: 225594: 2255‐‐2262.2262.Goldspink, G. 1999. Goldspink, G. 1999. Journal of AnatomyJournal of Anatomy 194(Pt 3): 323194(Pt 3): 323‐‐334. 334. Goldspink, G. 2002. Goldspink, G. 2002. Biochemical Society Transactions Biochemical Society Transactions 30: 28530: 285‐‐290. 290.
MUSCLE REMODELINGMUSCLE REMODELING
TRAINING STIMULUSTRAINING STIMULUS
DAMAGE??/TENSION??/ METABOLISM
IMMUNE SYSTEM IMMUNE SYSTEM REPEATED REPEATED RESPONSERESPONSE
Hoffman E.P. and Nader G.A. Balancing muscle and atrophy. Hoffman E.P. and Nader G.A. Balancing muscle and atrophy. Nature Nature MedicineMedicine 10: 58410: 584‐‐585, 2004585, 2004
Moore,M.S. and Urban R.J. An overview of the endocrinology of skMoore,M.S. and Urban R.J. An overview of the endocrinology of skeletal eletal muscle muscle Trends Endocrinol and Metab Trends Endocrinol and Metab 15: 11015: 110‐‐115, 2004115, 2004
Drummond M.J. et al. Nutritional and contractile Drummond M.J. et al. Nutritional and contractile regulation of human skeletal muscle protein regulation of human skeletal muscle protein synthesis and mTORC1 signaling. synthesis and mTORC1 signaling. JAP JAP 106:1374106:1374‐‐1384, 20091384, 2009
Protein + Carbohydrate Supplementation
Primary effects appear to be: Primary effects appear to be: •increased substrate availability•Increased insulin•carbohydrate blunting of cortisol release
MUSCLE REMODELINGMUSCLE REMODELING
TRAINING STIMULUSTRAINING STIMULUS
DAMAGE??/TENSION??/ METABOLISM
IMMUNE SYSTEM IMMUNE SYSTEM REPEATED REPEATED RESPONSERESPONSE
Hyperplasia and Satellite Cell Hyperplasia and Satellite Cell IncorporationIncorporation
Satellite cells (SC)Satellite cells (SC) are found in the mature muscle around the muscle fibers, are found in the mature muscle around the muscle fibers,
These cells are involved in the normal growth of muscle, as wellThese cells are involved in the normal growth of muscle, as well as regeneration following injury or as regeneration following injury or diseasedisease
Satellite cells are adult stem cells specific to skeletal muscleSatellite cells are adult stem cells specific to skeletal muscle fibers, and are also known as skeletal fibers, and are also known as skeletal muscle myoblasts.muscle myoblasts.
When muscle cells undergo trauma or injury, SC cells are releaseWhen muscle cells undergo trauma or injury, SC cells are released from beneath the basal lamina. d from beneath the basal lamina.
While normally in a postWhile normally in a post‐‐mitotic state, after muscle injury SC can remitotic state, after muscle injury SC can re‐‐enter the cell cycle and clone enter the cell cycle and clone themselves. These clones aggregate (fuse), again become postthemselves. These clones aggregate (fuse), again become post‐‐mitotic, and form a myotube. This mitotic, and form a myotube. This myotube differentiates into normal, complex muscle tissue, thus myotube differentiates into normal, complex muscle tissue, thus repairing the injured site repairing the injured site –– or the SC or the SC will donate its nuclear material to the damage cell to effect rewill donate its nuclear material to the damage cell to effect repair. This satellite cell activation and pair. This satellite cell activation and proliferation period lasts up to 48 hours after the trauma or shproliferation period lasts up to 48 hours after the trauma or shock from the resistance training session ock from the resistance training session stimulus stimulus
Hawke, T.J., and D. J. Garry. Myogenic satellite cells: physioloHawke, T.J., and D. J. Garry. Myogenic satellite cells: physiology to molecular biology. Journal of Applied Physiology. gy to molecular biology. Journal of Applied Physiology. 91: 53491: 534‐‐551, 2001. 551, 2001.
Research is currently underway to investigate whether satellite Research is currently underway to investigate whether satellite cells can differentiate into viable cells can differentiate into viable cardiac muscle cells. Normal cardiac cells are unable to regenercardiac muscle cells. Normal cardiac cells are unable to regenerate, which makes the cardiac muscle ate, which makes the cardiac muscle death of myocardial infarctions irreversible.death of myocardial infarctions irreversible.
Embryonic development: myoblasts fuse to Embryonic development: myoblasts fuse to form skeletal fibers. At the end of the form skeletal fibers. At the end of the developmental phase, some undifferentiated developmental phase, some undifferentiated myoblasts remain within the external lamina, myoblasts remain within the external lamina, at the periphery of mature, skeletal muscle at the periphery of mature, skeletal muscle fibers. These undifferentiated cells are fibers. These undifferentiated cells are satellite cells. Satellite cells are closely satellite cells. Satellite cells are closely associated with the sarcolemma of a muscle associated with the sarcolemma of a muscle fiber. They are typically present in the ratio of fiber. They are typically present in the ratio of approximately one, approximately one, mononucleatedmononucleated satellite satellite cell for every 100 muscle fiber nuclei with cell for every 100 muscle fiber nuclei with some fiber type differences.some fiber type differences.
Satellite Cell number appears to be fiber type dependent . Satellite Cell number appears to be fiber type dependent .
Type I : tend to have more Satellite cells Type I : tend to have more Satellite cells –– with aging Type I tend to have a five to six with aging Type I tend to have a five to six times greater satellite cell content than Type II fibers (satelltimes greater satellite cell content than Type II fibers (satellite cells disappear from type ite cells disappear from type II at a faster rate)?II at a faster rate)?
‐‐ may be due to an increased capillary (and nutrient) supply. may be due to an increased capillary (and nutrient) supply.
‐‐may be due to the fiber type use: Type 1 muscle fibers are used may be due to the fiber type use: Type 1 muscle fibers are used with greater frequency with greater frequency (low intensity activity, posture etc.), therefore, more satellit(low intensity activity, posture etc.), therefore, more satellite cells may be required for e cells may be required for ongoing minor injuries to muscleongoing minor injuries to muscle.
Feldman F. and Stockdale F.E. Skeletal muscle satellite cell diversity: Satellite cells form fibers of different types in cell culture. Dev Biol 143: 320‐334, 1991.
Verdijik L.B. et al. Satellite cell content is specifically reduced in type II skeletal muscle fibers in the elderly . Am J Physiol Endocrinol Metab 292: E151‐E157, 2007.
Exercise StimuliExercise Stimuli Connective and muscle tissue Connective and muscle tissue damage (ultrastructure) damage (ultrastructure) ––production of mitogens (MGF, production of mitogens (MGF, HGF etc. etc.)HGF etc. etc.)
Activation of Satellite Cells
Hyperplasia?Hyperplasia?
Fusion of Fusion of myoblast myoblast ‐‐ new new fiberfiber Donation of nuclear material to
existing muscle fiber
Evidence for HyperplasiaEvidence for Hyperplasia
Potential Mechanisms for Hyperplasia:Potential Mechanisms for Hyperplasia:
•• Fiber splitting Fiber splitting –– cells enlarge (by hypertrophy) to the point that cells enlarge (by hypertrophy) to the point that their nuclei and other organelles cannot control all the normal their nuclei and other organelles cannot control all the normal cellular functionscellular functions
Ho et al. Skeletal muscle fiber splitting with weightHo et al. Skeletal muscle fiber splitting with weight‐‐lifting exercise in rats. lifting exercise in rats. Am J AnatAm J Anat157: 433157: 433‐‐440, 1980440, 1980
Animal models for hypertrophy/hyperplasiaAnimal models for hypertrophy/hyperplasia
Stretch Stretch
Stretch Induced hypertrophy Stretch Induced hypertrophy ‐‐ chronic stretch (e.g. chronic stretch (e.g. –– hang an weight on a birds wing for weekshang an weight on a birds wing for weeks–– 10% of body mass) 10% of body mass)
••Weight pulls chronically on the back muscles of the bird. Weight pulls chronically on the back muscles of the bird.
••Causes hypertrophy Causes hypertrophy
••Causes some hyperplasiaCauses some hyperplasia
••Mechanism Mechanism –– stretch stretch –– myototic reflex myototic reflex –– pulling back pulling back
Sola O. et al. Sola O. et al. Exp NeuolExp Neuol 41: 7641: 76‐‐100, 1973100, 1973
Always S. et al. J Always S. et al. J Appl PhysiolAppl Physiol 66: 77166: 771‐‐781, 1989781, 1989
Antonio, J. et al. Antonio, J. et al. J. Appl PhysiolJ. Appl Physiol 75: 126375: 1263‐‐1271, 19931271, 1993
Siu P. and Alway S. J. Appl Physiol 99: 1897Siu P. and Alway S. J. Appl Physiol 99: 1897‐‐1904, 20051904, 2005
Review: Folland J.P. and Williams A.G. The adaptations to strengReview: Folland J.P. and Williams A.G. The adaptations to strength training: morphological and neurological th training: morphological and neurological contributions to increased strength. contributions to increased strength. Sports Medicine Sports Medicine 37: 14537: 145‐‐168, 2007168, 2007
Ablation/tenotomy a synergistic muscle (cut away gastrocnemius aAblation/tenotomy a synergistic muscle (cut away gastrocnemius and soleus nd soleus –– leaving leaving plantaris)plantaris)
••Walking on isolated muscle causes hypertrophy to occur as a resuWalking on isolated muscle causes hypertrophy to occur as a result of chronic dynamic lt of chronic dynamic overload. overload.
••Some studies show a small degree of hyperplasiaSome studies show a small degree of hyperplasia
••However However ‐‐ adaptations are a combination of endurance and resistance trainadaptations are a combination of endurance and resistance traininging
••Adaptations can be altered be training programsAdaptations can be altered be training programs
Goldberg A. Med Sci Sports 7: 185Goldberg A. Med Sci Sports 7: 185‐‐198, 1975198, 1975
Roy, R. et al. J Appl Physiol 83: 280Roy, R. et al. J Appl Physiol 83: 280‐‐290, 1997290, 1997
Animals lift weights for food Animals lift weights for food ‐‐ Gonyea et alGonyea et al’’s. Catss. Cats
Animals lifts weights (electric shock avoidance) Animals lifts weights (electric shock avoidance) –– HoHo’’s et als et al’’s ratss rats
•• Can cause considerable hypertrophy Can cause considerable hypertrophy
•• Volume effect Volume effect –– to a point the more work the greater the hypertrophy and to a point the more work the greater the hypertrophy and hyperplasiahyperplasia
Ho et al. (1980) Ho et al. (1980)
Following table Following table –– studies showing hyperplasia (early studies)studies showing hyperplasia (early studies)
Kelley G. J Appl PhysiolKelley G. J Appl Physiol 81: 158481: 1584‐‐1588, 19961588, 1996
Alway (1991) Alway (1991) Chronic stretch Quail ALD NAD Alway (1993) Alway (1993) Chronic stretch Quail ALD Histo Alway (1994) Alway (1994) Chronic stretch Quail ALD Histo Alway et al. (1990) Alway et al. (1990) Chronic stretch Quail ALD NAD Alway et al. (1989) Alway et al. (1989) Chronic stretch Quail ALD NAD and Hist Antonio and Gonyea (1993) Antonio and Gonyea (1993) Intermittent stretch Quail ALD Histo Antonio and Gonyea (1993) Antonio and Gonyea (1993) Intermittent stretch Quail ALD Histo Antonio and Goynea (1994) Antonio and Goynea (1994) Intermittent stretch Quail ALD Histo Gollnick et al. (1983) Gollnick et al. (1983) Chronic stretch Chicken ALD NAD Gollnick et al. (1981) Gollnick et al. (1981) Ablation Rat Soleus, plantaris, and EDL NAD Gonyea (1980) Gonyea (1980) Weights Cat FCR Histo Gonyea (1977) Gonyea (1977) Weights Cat FCR Histo Gonyea et al. (1986) Gonyea et al. (1986) Weights Cat FCR NAD Ho et al. (1980) Ho et al. (1980) Weights Rat AL Histo Tamaki et al. (1992) Tamaki et al. (1992) Sprints/weights Rat Plantaris NAD Timson et al. (1985) Timson et al. (1985) Ablation Mice Soleus NAD Vaughan and Goldspink (1979) Vaughan and Goldspink (1979) Tenotomy Mice Soleus Histo
Little doubt that at least in some in animal species, hyperplasiLittle doubt that at least in some in animal species, hyperplasia a can occurcan occur
What about humans? What about humans? –– typically cannot cut them up.typically cannot cut them up.
Human Methodology is indirect and difficultHuman Methodology is indirect and difficult
Human CrossHuman Cross‐‐sectional Studies:sectional Studies:
••Elite body male builders Elite body male builders –– larger total muscle Xlarger total muscle X‐‐sectional area sectional area –– however, fiber Xhowever, fiber X‐‐section was only slightly larger than section was only slightly larger than untrained control untrained control –– hyperplasia?hyperplasia?
MacDougall et al. MacDougall et al. J Appl PhysiolJ Appl Physiol 57: 139957: 1399‐‐14031403Larson and Tesch Larson and Tesch Eur J Appl PhysiolEur J Appl Physiol 55: 13055: 130‐‐136, 1986136, 1986
••Swimmers had larger deltoid total muscle area than control Swimmers had larger deltoid total muscle area than control ––fiber xfiber x‐‐sectional areas no different than untrained sectional areas no different than untrained control control –– hyperplasia?hyperplasia?
Nygaard and Nielson Nygaard and Nielson Swimming Medicine IVSwimming Medicine IV (6): 282(6): 282‐‐293, 1978. 293, 1978.
Elite male and female BB Elite male and female BB –– Total muscle crossTotal muscle cross‐‐sectional area correlated with both fiber Xsectional area correlated with both fiber X‐‐section and Numbersection and Number
Alway et al. Alway et al. J Appl PhysiolJ Appl Physiol 19891989
However, Most studies indicate no hyperplasia in BB However, Most studies indicate no hyperplasia in BB –– the increased total muscle crossthe increased total muscle cross‐‐section is due to hypertrophy section is due to hypertrophy (i.e. fibers have greater X(i.e. fibers have greater X‐‐section) section)
Haggemerk et al. Haggemerk et al. Scand J Clin Lab Invest Scand J Clin Lab Invest 38: 35538: 355‐‐360, 1978360, 1978MacDougall et al. J Appl Physiol 57: 1399MacDougall et al. J Appl Physiol 57: 1399‐‐1403, 19841403, 1984Schantz et al. Acta Physiol Scand 113: 5370539, 1981Schantz et al. Acta Physiol Scand 113: 5370539, 1981
Humans and Hyperplasia: longitudinal studiesHumans and Hyperplasia: longitudinal studies
Not much evidence of hyperplasia Not much evidence of hyperplasia –– increased cross sectional increased cross sectional area in response to resistance training is caused by area in response to resistance training is caused by hypertrophyhypertrophy
However, no longHowever, no long‐‐term studiesterm studies
McCall et al. J Appl Physiol 81: 2004‐2012, 1996
Abernethy et al. Sports Medicine 17:22‐38, 1996
•• Satellite cell incorporation Satellite cell incorporation –– SCSC’’s proliferate form new myoblast s proliferate form new myoblast (immature Muscle cells) (immature Muscle cells) –– myoblasts either fuse with an existing myoblasts either fuse with an existing cell or fuse with each other to form a new muscle fiber. cell or fuse with each other to form a new muscle fiber.
Winchester P.K. et al. Satellite cell activation of the stretchWinchester P.K. et al. Satellite cell activation of the stretch‐‐enlarged anterior latissimus dorsi of the adult quail. enlarged anterior latissimus dorsi of the adult quail. Am J Am J PhysiolPhysiol 260:C206260:C206‐‐C212, 1991C212, 1991
Kadi F. et al. Concomitant increases in myonuclear and satellitKadi F. et al. Concomitant increases in myonuclear and satellite cell content in female trapezius muscle following e cell content in female trapezius muscle following strength training. strength training. Histochem and Cell BiolHistochem and Cell Biol 113: 99113: 99‐‐103, 2000103, 2000
Review: Folland J.P. and Williams A.G. The adaptations to strengReview: Folland J.P. and Williams A.G. The adaptations to strength training: morphological and neurological th training: morphological and neurological contributions to increased strength. contributions to increased strength. Sports Med Sports Med 37: 14537: 145‐‐168, 2007168, 2007
Heredity
Recovery /Adaptation
HEREDITYHEREDITYWORKWORK
SCHOOLSCHOOL
SOCIAL LIFESOCIAL LIFEGirl /boy friend Girl /boy friend ‐‐ AlcoholAlcohol
Wife/mistress Other bad habitsWife/mistress Other bad habits
Sheep, Dogs and Cats etc. etc. Sheep, Dogs and Cats etc. etc. TRAININGTRAINING
DAILY DAILY IRRITANTS: CELL IRRITANTS: CELL PHONE, BANKS, PHONE, BANKS, INSURANCE, IRS INSURANCE, IRS ETC. ETC.
Individual differences:Individual differences:
Genetics versus EnvironmentGenetics versus EnvironmentHeredity - the most important factor influencing performance because:
1. Genetically linked physiological characteristics are associated with specific performance abilities
2. Genetic makeup establishes the boundary for adaptation
Some athletes boundary’s are more narrow than others (less adaptability)
Klissouras, V. Adaptability of genetic variation. Klissouras, V. Adaptability of genetic variation. J Appl PhysiolJ Appl Physiol 31: 33831: 338--344, 1971.344, 1971.
Bouchard, C. et al. Genetics of aerobic and anaerobic performanBouchard, C. et al. Genetics of aerobic and anaerobic performance. ce. Med Sci Sports ExercMed Sci Sports Exerc20:2720:27--58, 199258, 1992
STRENGTH/POWER ATHLETES: HERITABILITYSTRENGTH/POWER ATHLETES: HERITABILITY1.1. HIGH TESTOSTERONE CONCENTRATIONSHIGH TESTOSTERONE CONCENTRATIONS
Harris J.A. et al. The heritability of testosterone: a study of Dutch adolescent twins and their parents. Behav Genet 28:165‐171.
Hoekstra R.A. et al. Heritability of testosterone levels in 12‐year‐old twins and its relation to pubertal development. Twin Res Hum Genet. 9(4):558‐65, 2006
Kuijpers E.A. et al. Heritability of reproductive hormones in adult male twins. Hum Reprod.:2153‐9, 2007
Bogart, G. et al. Heritability of blood concentrations of sex‐steroids in relation to body composition in young adult male siblings. Clin Endocrinol (Oxf). 69:129‐35. 2008
2.2. ACTN3 GENOTYPE (SKELETAL MUSCLE ACTINACTN3 GENOTYPE (SKELETAL MUSCLE ACTIN‐‐BINDING PROTEIN ALPHABINDING PROTEIN ALPHA‐‐ACTININACTININ‐‐3 3 ––TYPE II FIBRES)TYPE II FIBRES)
Yang, N. et al. ACTN3 genotype is associated with elite athletic performance. Am J Hum Genet73:627‐631, 2003.
3.3. ENHANCED MOTOR CONTROL AT FAST SPEEDSENHANCED MOTOR CONTROL AT FAST SPEEDS
Missitzi, J. and V. Klissouras. Heritability of neuromuscular coordination: Implications for control strategies. Med Sci Sport Exerc 36:233‐240, 2004.
Genetics: Hard GainersGenetics: Hard Gainers
REGARDLESS OF THE PROGRAM SOME INDIVIDUAL ATHLETES REGARDLESS OF THE PROGRAM SOME INDIVIDUAL ATHLETES WILL NOT GAIN MUCH SIZE AND RELATIVELY LESS STRENGTH WILL NOT GAIN MUCH SIZE AND RELATIVELY LESS STRENGTH AND POWERAND POWER
Van Etten L.M. et al. Effect of body build on weight-training-induced adaptations in body composition and muscular strength. Med Sci Sports Exerc 26:515-521, 1994. (somatotype)
Training Methods: factors effecting Hypertrophy, strength and power.
A Brief (very) Discussion)
Considerable data on mechanism of hypertrophy – Very little on methods
3. Sex3. Sex 3. Training Intensity3. Training Intensity
4. Age4. Age 4. 4. Rest/RecoveryRest/Recovery PeriodsPeriods
5. 5. Length of Training Sessions/Length of Training Sessions/
number of sessionsnumber of sessions
6. Time of day6. Time of day
7. Warm7. Warm‐‐up up –– catecholamine release, etc.catecholamine release, etc.
Volume (Work) EffectsVolume (Work) Effects
Volume Effects:
Krieger J.W. Single versus multiple sets for muscle hypertrophy: a meta‐analysis JSCR 24: 1150‐1159, 2010
Volume effects: Volume effects:
Frobose et al. Frobose et al. Z Orthop Ihre Grenzgeb Z Orthop Ihre Grenzgeb 131(2):164131(2):164‐‐167, 1993167, 1993
Found that hypertrophy is better stimulated by higher volume‐loads
Stone et al. Stone et al. Strength and Cond. Strength and Cond. 18(3):4418(3):44‐‐51, 199651, 1996
Noted that elite bodybuilders, weightlifters and powerlifters have similar hypertrophy (x‐sec) levels in commonly used muscles even though these athletes train very differently – suggested that over a long‐term that volume effects play major role ‐ total work may be more important than number of reps per set among (except maybe for beginners)
Manipulation of intensity (within volume) effects on strength in well‐trained athletes:
Using higher volumes of moderateUsing higher volumes of moderate‐‐ heavy loading produces greater heavy loading produces greater strength gains then high volumes or low volumes.strength gains then high volumes or low volumes.
GonzalezGonzalez‐‐Badillo J.J Moderate volume of high relative training intensity Badillo J.J Moderate volume of high relative training intensity produces greater strength produces greater strength gains compared with low and high volumes in competitive weightligains compared with low and high volumes in competitive weightlifters. JCSR fters. JCSR 20:73‐81, 2006
Relative Intensity: Training to FailureRelative Intensity: Training to Failure
Training to Failure Training to Failure
Stone et al. Stone et al. Strength and Cond. Strength and Cond. 18(3):4418(3):44‐‐51, 199651, 1996
First suggested that training to failure was not needed to induce significant hypertrophy, strength or power
• Bodybuilders often train to failure – based on biopsy of same muscle group hypertrophy is not statistically greater than other strength trained athletes (i.e. powerlifters and weightlifters) – type I versus type II• Bodybuilders are not stronger (usually not as strong) as other strength‐power athletes • Short‐term (muscular) endurance might be enhanced
Frobose et al. Frobose et al. Z Orthop Ihre Grenzgeb Z Orthop Ihre Grenzgeb 131(2):164131(2):164‐‐167, 1993167, 1993
•Found that hypertrophy is better stimulated by higher volume‐loads
•Training to failure was not necessary to activate higher threshold motor units•Ballistic exercise also ⇑ recruitment of higher threshold motor units
Training to Failure
• Peterson M. et al. JSCR, 19(4):950‐958, 2005.– Meta‐analysis: Training to
failure does not result in significantly greater strength gains than not training to failure.
Training to Failure
• Izquierdo M. et al. JAP, 100:1647‐1656, 2006.– Subjects:
• 42 recreationally trained men
– Methods:• 16 weeks periodized training • Two treatment groups
– Sets to Failure (SF)– No sets to Failure (NSF)
– Results:
•• SF produced > (marginally) performance gains in HIE enduranceSF produced > (marginally) performance gains in HIE endurance•• NSF produced > performance gains in power NSF produced > performance gains in power •• NSF stimulated > resting IGF, Testosterone and < CortisolNSF stimulated > resting IGF, Testosterone and < Cortisol
Single versus Multiple SessionsSingle versus Multiple Sessions
General Consensus Among Coaches and Sport Scientists General Consensus Among Coaches and Sport Scientists ––
Theoretical paradigm – interval training – higher intensity can be maintained when work is broken up
1.Multiple training sessions produce superior results2.Volume of training must not be excessive3.Subsequent training can be effected by previous training (i.e. fatigue management) – at least 4 hrs recovery between sessions?
Not much research availableNot much research available
Hakkinen K. and Pakarinen A. Serum hormones in male strength atlHakkinen K. and Pakarinen A. Serum hormones in male strength atletes during etes during intensive short term strength training. Eur J Appl Physiol 63: intensive short term strength training. Eur J Appl Physiol 63: 194194‐‐199. 199.
HHääkkinen K. and Kallinen M.(1994) Distribution of strength volume kkinen K. and Kallinen M.(1994) Distribution of strength volume into one or two into one or two daily sessions and neuromuscular adaptations in female athletes.daily sessions and neuromuscular adaptations in female athletes. Electromyogr. Clin. Electromyogr. Clin. Neurophysiol., Neurophysiol., 34:11734:117‐‐124.124.
Hartman, M. et al. (2007) Comparisons between twiceHartman, M. et al. (2007) Comparisons between twice‐‐daily and once daily training daily and once daily training sessions in male weightlifters sessions in male weightlifters IJSP & P IJSP & P 2:2: 159159‐‐169.169.
Methods:Compared equal training volume that were either encountered in one or two training sessions in one day
10 competitive female strength athletes3 week training blocks of either 1 or 2 sessions a day
The total daily volume encountered was identicalResults:
2 sessions a day produced greater⇑ in muscular strength (p < 0.05)⇑⇑ in muscle cross sectional area in muscle cross sectional area (p <0.05)⇑ in IEMG of trained muscles (not statistically significant)
Conclusion: Multiple Training Sessions in One Day likely Conclusion: Multiple Training Sessions in One Day likely Enhance the Adaptive Response to Training in Advanced Enhance the Adaptive Response to Training in Advanced AthletesAthletes
HHääkkinen and Kallinen kkinen and Kallinen Electromyogr. Clin. Neurophysiol., Electromyogr. Clin. Neurophysiol., 34:11734:117‐‐124, 124, 19941994
InterInter‐‐Set Rest PeriodsSet Rest Periods
Descriptive: ‐ greater volume loads with longer rest/set – assumed to stimulate greater gains:
•Willardson and Burnett A comparison of 3 Different Rest Intervals on the Exercise Volume Completed During A Workout. JSCR 19: 23‐26, 2005
•Rahimi R. Effect Of Different Rest Intervals On The Exercise Volume Completed During Squat Bouts. J Sports Sci & Med 4: 361‐366, 2005
Training studies (greater strength gains with > rest):
•Robinson, J.M., et al. Effects of different weight training exercise-rest intervals on strength, power and high intensity endurance. JSCR , 9: 216‐221, 1995.
•Willardson and Burnett The Effect Of Different Rest Intervals Between Sets On Volume Components And Strength Gains JSCR 22: 146‐152, 2008
Training studies (greater CSA gains with > rest: 1 vs 2.5 min):
•Buresh R., Berg K. and French J. The effect of resistive exercise rest intervals on hormonal response, strength and hypertrophy with training JSCR 23:62‐71, 2009
Training studies (equal results: 2 vs 5 min rest):
•Ahtiainen J.P. Short vs. long rest period between the sets in hypertrophic resistance training: influence on muscle strength, size, and hormonal adaptations in trained men. JSCR. 19(3):572‐82, 2005
Rest periods do appear to make a marked difference in Rest periods do appear to make a marked difference in the training intensity and volume load accomplished the training intensity and volume load accomplished ‐‐the greater loading and total work will likely result in the greater loading and total work will likely result in superior improvements in strength and power. superior improvements in strength and power. ‐‐ rest rest periods should be greater than 1 min: 3periods should be greater than 1 min: 3‐‐ 5 min 5 min appearappear to to be optimal for simultaneous strength, power be optimal for simultaneous strength, power and CSA and CSA gainsgains
de Salles B.F. et al. Rest interval between sets in strength training. Sports Med. 2009;39(9):765‐77
There is little evidence that short rest periods enhance There is little evidence that short rest periods enhance HIE endurance:HIE endurance:
García‐López D. et al. Effects of short vs. long rest period between sets on elbow‐flexor muscular endurance during resistance training to failure. JSCR:1320‐4, 2007.
Robinson, J.M., et al. Effects of different weight training exercise-rest intervals on strength, power and high intensity endurance. JSCR , 9: 216‐221, 1995.
Final thoughts:
Relationship between hypertrophy and performance is complex at best:
To an extent there are some individual variations –but in general using these ideas may increase hypertrophy adaptation:
