Dynamic properties of mammalian skeletal muscles.

Introduction. ............................................................ 129 Fiber Types. ............................................................ 130 Historical introduction. ................................................. 130 Classification and terminology. ........................................... 131 Contractile properties of different types of fiber. ............................ 134 Mechanical Properties. .................................................... 138 Introduction ........................................................... 138 Series-elastic component. ................................................ 138 Length : tension relation of contractile material. ............................. 140 Force: velocity properties of contractile component. ......................... 145 Behavior of series-elastic and contractile components in isotonic and isometric contractions ....................................................... 147 Active state, time course of isometric twitch, and posttetanic potentiation ....... 149 Ontogenetic Differentiation of Fast and Slow Muscles. ......................... 161 Growth ............................................................... 161 Dynamic properties. .................................................... 163 Other developmental changes. .......................................... 166 Kelation Between Size and Speed of Contraction .............................. 166 Speed of contraction of homologous muscles of different species. ............. 166 Speed of contraction of different muscles of same animal. .................... 169 Neural Control of Dynamic Properties. ...................................... 170 Introductiorl ........................................................... 170 Dynamic properties of normal and cross-innervated muscles .................. 172 Effects of nerve cross-union on properties of myosin. ......................... 175 Neural influences on noncontractile structures in muscle cells ................. 176 Correlations Between Dynamic and Chemical Properties of Contractile Material. .. 177 Introduction ........................................................... 177 Structure of myosin. .................................................... 177 Relation between ATPase activity of myosin and intrinsic speed of shortening . 181 Functional differences between fast and slow muscles. ....................... 182 Review of Some Major Problems ........................................... 183