Components of the skeletal muscle musclefibrebundle musclefibre Sacromer (area between the Z-discs) with actin & myosin
Atopdown top-down view of skeletal muscle
Organisation of Contractile Proteins in Muscle Muscle Myofiber (Musclefiber) Myofibril Sarcomere Thin Filament (actin) Thick Filament (myosin) Organized arrays of muscle fibers. A single multinucleate muscle cell containing all the usual cell organelles plus many myofibrils. End to end arrays of identical sarcomeres The unit of contractile activity composed mainly of actin and myosin and extending from Z line to Z line in a myofibril. Composed of a linear array of hundreds of globular, actin monomers in a double helical. arrangement Composed of hundreds of long, contractile myosin molecules arranged in a staggered side by side complex.
Components of the Musclefibre 75% water 5% minerals, ATP,Glycogen,Cre subtrates atine-phosphate 20% proteins 80% myofilaments, enzyms, myoglobin (red color)
Important Minerals & Substrates Ca+: triggerfunction (activates actin) no contraction without Ca+ activates enzyme ATP-ase ATP: softenerfunction without ATP muscle becomes stiff contraction only with enough ATP & ATP-ase
Types of Fibres 1 (ST-fibre) or Typ I Red Fibres (slow, fatigue resistant) 2 (FT0-fibre) or Type IIa/b Intermediate Fibres (fast, fatigue resistant) 3 (FT-fibre) or Type IIc 3 (FT fibre) or Type IIc White Fibres (fast, short-term powerfull)
FT vs. ST FT-fibre fast contraction powerful fast fatigue white, less myoglobin more myofibrills bigger crossection less capilaries less mitochondrias anaerobic metabolism predominates speed, maximum power ST-fibre slow contraction less power resistant to fatigue red, many myoglobin less myofibrills less crossection o many capilaries many mitochondrias aerobic metabolism predominates endurance activity
FT-fibre-rates rates in several kinds of sport 90 80 70 60 Marathon runners Long distance swimmers Cyclists Rowers 50 Swimers 40 30 20 10 0 p Walkers Hockey Untrained Sprinters
sportive training: forces the organism to adaptions isometric training Hypertrophy (no Hyperplasy) (short term power, maximum power) Thickening of single m.-fibres glycolytic capacity isotonic training (endurance) moderate Hypertrophy capilartiy - energetic capacity ; - improved O 2 -supply, - transportation of metabolits mitochondria -density - number ATP/CP Glycogen enzyms
sportive training: forces the organism to adaptions training with increasing intensity (weight lifting, bodybuilding) b modifications @ sakromers training with increasing stress modifications @ sakromers & mitochondria (aim: endurance & power (team games (BB))
sportive training: forces the organism to adaptions endurance training (40-60 d) 18 % more mitochondria 37 % more m.-surface Changes are influenced by hormons + 45 % kapilaries (50x better O 2 -supply) speed / short term power (many FT-fibres) selectiv hypertrophy h FTg-fibres less mitochondria / -density better conditions for Glycolysis
Muscle cramps: sportive training: other effects electrolyte disturbance, heat, hydropenia (water lack), intensive competitions medcine orthopedic reasons, leg-length-difference, disturbed feetmuscle-mechanic further reasons: disturbance of blood circulation myalgia: diff. muscle pain, inflamations diabetes, intoxications (nicotine, alc.)
sportive training: other effects Muscular aching (soreness of m.): temporary painful fatigue of muscles (maybe with cramps), apear 1-2d after training mainly after eccentric load (downhill walking, jumps into deep, etc). reason: local overloads causes microtrauma in myofibrils (mainly in Z-discs) pain comes from inflammations and oedema in muscle wear off after 1 or 2 days