Comprehensive Physiology Wiley Online Library

Mechanical and Electrical Properties of Respiratory Muscles

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 Basic Concepts—Review of Muscle Mechanics
1.1 Muscle Fiber Types
1.2 Mechanics of Muscle
1.3 Electrical Properties of Skeletal Muscle
2 Individual Respiratory Muscles and Their Properties
2.1 General Considerations
2.2 Diaphragm
2.3 Intercostal Muscles
2.4 Sternocleidomastoid and Scalenus Muscles
2.5 Abdominal Muscles
2.6 Other Respiratory Muscles
3 Altered Respiratory Muscle Mechanical Properties in Disease
3.1 Obstructive Lung Disease
3.2 Diseases Characterized by Stiff Lungs
3.3 Neuromuscular Diseases
3.4 Severe Obesity
Figure 1. Figure 1.

Load‐extension or stress‐strain curve of rat gracilis anticus muscle. Mean ± se of 5 muscles.

From Bahler et al. 12
Figure 2. Figure 2.

Active (upper) and passive (lower) length‐tension curves of rat gracilis muscle. Resting in situ length, 2.6 cm; muscle wt, 50 mg; maximum force, 25 g; stimulation tetanic at 95 Hz; temperature, 17.6°C.

From Bahler et al. 12
Figure 3. Figure 3.

Active and passive length‐tension curves of dog diaphragmatic strip with intact nerve and blood supply. Both force and length normalized (l0, resting in situ length); stimulation supramaximal via the phrenic nerve at 120 Hz; temperature, 38°C. Average values from 13 dogs.

From Kim et al. 143
Figure 4. Figure 4.

Active length‐tension curve of frog muscles in relation to sarcomere lengths. (Should be considered together with Fig. 5A, B in relating changes in thick and thin filament relationships and their overlap to the length‐tension curve.) Arrows are placed opposite striation spacings at which critical stages of filament overlap occur, numbered as in Fig. 5B.

From Gordon et al. 106
Figure 5. Figure 5.

A: schematic diagram of sarcomere filaments, indicating nomenclature for relevant dimensions. B: critical stages in increase in overlap between thick and thin filaments as sarcomere shortens.

From Gordon et al. 106
Figure 6. Figure 6.

Isometric‐twitch and tetanus responses for the inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles of mouse. Records obtained at optimum length for isometric tetanic contractions at 35°C. Stimulus frequencies for all unfused tetanic contractions (middle panels) were 50 Hz. Stimulus frequencies for fused tetanic contractions (right panels) were IR, 500 Hz; EDL, 500 Hz; DIA, 200 Hz; SOL, 150 Hz.

From Luff 162
Figure 7. Figure 7.

Normalized isotonic force‐velocity curves of rat gracilis muscle at various lengths of the contractile component, l0′, Resting in situ length.

From Bahler et al. 12
Figure 8. Figure 8.

Three‐dimensional plot representing dynamic length‐force‐velocity phase space of contractile component of rat gracilis muscle.

From Bahler et al. 12
Figure 9. Figure 9.

Relationships between force‐velocity curve and the power‐velocity curve, illustrating that there is an optimal velocity at which efficiency of power generation is maximal. Force, velocity, and work are in arbitrary units. Upper panels: dashed curves, situation in which shortening velocities are half those represented by solid curves. Optimum velocity is shifted. Lower panels: dashed curves, situation in which forces but not shortening velocities are halved. Optimal velocity of shortening remains unchanged.

Figure 10. Figure 10.

Length‐tension curves of dog diaphragm, flexor carpi radialis, and sartorius. Whole muscle used with intact nerve and blood supply. Stimulation was supramaximal via nerve at 100 Hz. Temperature, 38°C.

Data from L. M. Klemka, unpublished observations
Figure 11. Figure 11.

Force‐velocity curves for inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles in mouse. Ordinate is speed of sarcomere shortening and abscissa is isotonic load as fraction of maximum isometric tetanic tension.

From Luff 162


Figure 1.

Load‐extension or stress‐strain curve of rat gracilis anticus muscle. Mean ± se of 5 muscles.

From Bahler et al. 12


Figure 2.

Active (upper) and passive (lower) length‐tension curves of rat gracilis muscle. Resting in situ length, 2.6 cm; muscle wt, 50 mg; maximum force, 25 g; stimulation tetanic at 95 Hz; temperature, 17.6°C.

From Bahler et al. 12


Figure 3.

Active and passive length‐tension curves of dog diaphragmatic strip with intact nerve and blood supply. Both force and length normalized (l0, resting in situ length); stimulation supramaximal via the phrenic nerve at 120 Hz; temperature, 38°C. Average values from 13 dogs.

From Kim et al. 143


Figure 4.

Active length‐tension curve of frog muscles in relation to sarcomere lengths. (Should be considered together with Fig. 5A, B in relating changes in thick and thin filament relationships and their overlap to the length‐tension curve.) Arrows are placed opposite striation spacings at which critical stages of filament overlap occur, numbered as in Fig. 5B.

From Gordon et al. 106


Figure 5.

A: schematic diagram of sarcomere filaments, indicating nomenclature for relevant dimensions. B: critical stages in increase in overlap between thick and thin filaments as sarcomere shortens.

From Gordon et al. 106


Figure 6.

Isometric‐twitch and tetanus responses for the inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles of mouse. Records obtained at optimum length for isometric tetanic contractions at 35°C. Stimulus frequencies for all unfused tetanic contractions (middle panels) were 50 Hz. Stimulus frequencies for fused tetanic contractions (right panels) were IR, 500 Hz; EDL, 500 Hz; DIA, 200 Hz; SOL, 150 Hz.

From Luff 162


Figure 7.

Normalized isotonic force‐velocity curves of rat gracilis muscle at various lengths of the contractile component, l0′, Resting in situ length.

From Bahler et al. 12


Figure 8.

Three‐dimensional plot representing dynamic length‐force‐velocity phase space of contractile component of rat gracilis muscle.

From Bahler et al. 12


Figure 9.

Relationships between force‐velocity curve and the power‐velocity curve, illustrating that there is an optimal velocity at which efficiency of power generation is maximal. Force, velocity, and work are in arbitrary units. Upper panels: dashed curves, situation in which shortening velocities are half those represented by solid curves. Optimum velocity is shifted. Lower panels: dashed curves, situation in which forces but not shortening velocities are halved. Optimal velocity of shortening remains unchanged.



Figure 10.

Length‐tension curves of dog diaphragm, flexor carpi radialis, and sartorius. Whole muscle used with intact nerve and blood supply. Stimulation was supramaximal via nerve at 100 Hz. Temperature, 38°C.

Data from L. M. Klemka, unpublished observations


Figure 11.

Force‐velocity curves for inferior rectus (IR), extensor digitorum longus (EDL), diaphragm (DIA), and soleus (SOL) muscles in mouse. Ordinate is speed of sarcomere shortening and abscissa is isotonic load as fraction of maximum isometric tetanic tension.

From Luff 162
References
 1. Adrian, R. H., W. K. Chandler, and A. L. Hodgkin. Voltage clamp experiments in striated muscle fibres. J. Physiol. London 208: 607–644, 1970.
 2. Adrian, R. H., W. K. Chandler, and A. L. Hodgkin. Slow changes in potassium permeability in skeletal muscle. J. Physiol. London 208: 645–668, 1970.
 3. Adrian, R. H., and W. H. Freygang. The potassium and chloride conductance of frog muscle membrane. J. Physiol. London 163: 61–103, 1962.
 4. Agostoni, E., E. J. M. Campbell, and S. Freedman. Energetics. In: The Respiratory Muscles: Mechanics and Neural Control, edited by E. J. M. Campbell, E. Agostoni, and J. Newsom Davis. Philadelphia, PA: Saunders, 1970, p. 123–125.
 5. Agostoni, E., and W. O. Fenn. Velocity of muscle shortening as a limiting factor in respiratory air flow. J. Appl. Physiol. 15: 349–353, 1960.
 6. Agostoni, E., G. Sant'Ambrogio, and H. del Portillo Carrasco. Electromyography of the diaphragm in man and transdiaphragmatic pressure. J. Appl. Physiol. 15: 1093–1097, 1960.
 7. Ahlgren, J. Mechanisms of mastication: a quantitative cinematographic and electromyographic study of masticatory movements in children with special reference to occlusion of the teeth. Acta Odontol. Scand. Suppl. 44: 1–109, 1966.
 8. Ahlgren, J., and D. R. Lipke. Electromyographic activity in digastric muscles and opening force of mandible during static and dynamic conditions. Scand. J. Dent. Res. 85: 152–154, 1977.
 9. Andersen, P., and T. A. Sears. The mechanical properties and innervation of fast and slow motor units in the intercostal muscles of the cat. J. Physiol. London 173: 114–129, 1964.
 10. Arora, N. S., and D. F. Rochester. Effect of body weight and muscularity on human diaphragm muscle mass, thickness, and area. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 52: 64–70, 1982.
 11. Aubert, X., and J. de Loff. Influence des ions sur le fonctionnement musculaire. Arch. Int. Physiol. 55: 307–309, 1948.
 12. Aubier, M., G. Farkas, A. De Troyer, R. Mozes, and C. Roussos. Detection of diaphragmatic fatigue in man by phrenic stimulation. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 50: 538–544, 1981.
 13. Bahler, A. S., J. T. Fales, and K. L. Zierler. The active state of mammalian skeletal muscle. J. Gen. Physiol. 50: 2239–2253, 1967.
 14. Bahler, A. S., J. T. Fales, and K. L. Zierler. The dynamic properties of mammalian skeletal muscle. J. Gen. Physiol. 51: 369–384, 1968.
 15. Banus, M. G., and A. Zetlin. The relation of isometric tension to lengths in skeletal muscle. J. Cell. Comp. Physiol. 12: 403–420, 1938.
 16. Bárány, M. ATPase activity of myosin correlated with speed of muscle shortening. J. Gen. Physiol. 50: 197–216, 1967.
 17. Bárány, M., K. Bárány, T. Reckard, and A. Volpe. Myosin of fast and slow muscles of the rabbit. Arch. Biochem. Biophys. 109: 185–191, 1965.
 18. Bárány, M., T. E. Conover, L. H. Schliselfeld, E. Gaetjens, and M. Goffart. Relation of properties of isolated myosin to those of intact muscles of the cat and sloth. Eur. J. Biochem. 2: 156–164, 1967.
 19. Bárány, M., A. F. Tucci, K. Bárány, A. Volpe, and T. Reckard. Myosin of newborn rabbits. Arch. Biochem. Biophys. 111: 727, 1965.
 20. Barnard, R. J., V. R. Edgerton, T. Furukawa, and J. B. Peter. Histochemical, biochemical, and contractile properties of red, white, and intermediate fibers. Am. J. Physiol. 220: 410–414, 1971.
 21. Barnard, R. J., and J. B. Peter. Effect of training and exhaustion on hexokinase activity of skeletal muscle. J. Appl. Physiol. 27: 691–695, 1969.
 22. Basmajian, J. V. Muscles Alive: Their Functions Revealed by Electromyography (4th ed.). Baltimore, MD: Williams & Wilkins, 1978, p. 23–37.
 23. Bauwens, P. Electromyography. Br. J. Phys. Med. 11: 130–136, 1948.
 24. Bergström, R. M. The relation between the number of impulses and the integrated electric activity in electromyogram. Acta Physiol. Scand. 45: 97–101, 1959.
 25. Bernhard, C. G., U. S. von Euler, and C. R. Skoglund. Post‐tetanic action potentials in mammalian muscle. Acta Physiol. Scand. 2: 284–288, 1941.
 26. Berson, R. S., and L. N. Mishin. Auto‐ and cross‐correlation analysis of the electrical activity of muscles. Med. Electron. Biol. Eng. 2: 155–159, 1964.
 27. Bigland, B., and O. C. J. Lippold. The relation between force‐velocity and integrated electrical activity in human muscles. J. Physiol. London 123: 214–224, 1954.
 28. Bigland‐Ritchie, B., and J. J. Woods. Integrated EMG and oxygen uptake during dynamic contractions of human muscles. J. Appl. Physiol. 36: 475–479, 1974.
 29. Biscoe, T. J. The isometric contraction characteristics of cat intercostal muscle. J. Physiol. London 164: 189–199, 1962.
 30. Brandstater, M. E., and E. H. Lambert. Motor unit anatomy. In: New Developments in Electromyography and Clinical Neurophysiology, edited by J. E. Desmedt. Basel: Karger, 1973, vol. 1, p. 14–22.
 31. Brooke, M. H., and K. K. Kaiser. Some comments on the histochemical characterization of muscle adenosine triphosphatase. J. Histochem. Cytochem. 17: 431–432, 1969.
 32. Brooke, M. H., and K. K. Kaiser. Muscle fiber types: how many and what kind? Arch. Neurol. 23: 369–379, 1970.
 33. Brown, D. E. S. Effect of rapid compression upon events in isometric contraction of skeletal muscle. J. Cell. Comp. Physiol. 8: 141–157, 1936.
 34. Brown, G. L., and U. S. von Euler. The after effects of a tetanus on mammalian muscle. J. Physiol. London 93: 39–60, 1938.
 35. Buchthal, F., F. Erminio, and P. Rosenfalck. Motor unit territory in different human muscles. Acta Physiol. Scand. 45: 72–87, 1959.
 36. Buchthal, F., C. Guld, and P. Rosenfalck. Action potential parameters in normal human muscle and their dependence on physical variables. Acta Physiol. Scand. 32: 200–218, 1954.
 37. Buchthal, F., C. Guld, and P. Rosenfalck. Multielectrode study of the territory of a motor unit. Acta Physiol. Scand. 39: 83–103, 1957.
 38. Buchthal, F., P. Pinelli, and P. Rosenfalck. Action potential parameters in normal human muscle and their physiological determinants. Acta Physiol. Scand. 32: 219–229, 1954.
 39. Bullard, H. H. Histological as related to physiological and chemical differences in certain muscles of the cat. Johns Hopkins Hosp. Rep. 18: 323–328, 1919.
 40. Buller, A. J. The neural control of the contractile mechanism in skeletal muscle. Endeavour 29: 107–111, 1970.
 41. Buller, A. J., J. C. Eccles, and R. M. Eccles. Differentiation of fast and slow muscles in the cat hind limb. J. Physiol. London 150: 399–416, 1960.
 42. Burke, R. E., and P. Tsairis. Anatomy and innervation ratios in motor units of cat gastrocnemius. J. Physiol. London 234: 749–765, 1973.
 43. Butler, C. Diaphragmatic changes in emphysema. Am. Rev. Respir. Dis. 114: 155–160, 1976.
 44. Campbell, E. J. M. The role of scaleni and sternomastoid muscles in breathing in normal subjects. An EMG study. J. Anat. 89: 378–386, 1955.
 45. Carlsen, F., F. Fuchs, and G. G. Knappeis. Contractility and ultrastructure in glycerol‐extracted muscle fibers. I. The relationship of contractility to sarcomere length. J. Cell Biol. 27: 25–34, 1965.
 46. Carlsen, F., F. Fuchs, and G. G. Knappeis. Contractility and ultrastructure in glycerol‐extracted muscle fibers. II. Ultrastructure in resting and shortened fibers. J. Cell Biol. 27: 35–46, 1965.
 47. Cattell, M., and D. J. Edwards. The energy changes of skeletal muscle accompanying contraction under high pressure. Am. J. Physiol. 86: 371–382, 1928.
 48. Chaffin, D. B. Localized muscle fatigue—definition and measurement. J. Occup. Med. 15: 346–354, 1973.
 49. Clamann, H. P. Statistical analysis of motor unit firing patterns in a human skeletal muscle. Biophys. J. 9: 1233–1251, 1969.
 50. Close, J. R., E. D. Nickle, and F. Todd. Motor unit action‐potential counts: their significance in isometric and isotonic contractions. J. Bone Jt. Surg. Am. Vol. 42: 1207–1222, 1960.
 51. Close, R. Dynamic properties of fast and slow skeletal muscles of the rat during development. J. Physiol. London 173: 74–95, 1964.
 52. Close, R. Force: velocity properties of mouse muscle. Nature London 206: 718–719, 1965.
 53. Close, R. Effects of cross union of motor nerves to fast and slow skeletal muscles. Nature London 206: 831–832, 1965.
 54. Close, R. The relation between intrinsic speed of shortening and duration of the active state of muscle. J. Physiol. London 180: 542–559, 1965.
 55. Close, R. Dynamic properties of fast and slow muscles in mammals. In: Exploratory Concepts in Muscular Dystrophy and Related Disorders, edited by A. T. Milhorat. Amsterdam: Excerpta Med., 1967, p. 142–149.
 56. Close, R. Dynamic properties of fast and slow skeletal muscles of the rat after nerve cross union. J. Physiol. London 204: 331–346, 1969.
 57. Close, R. I. Dynamic properties of mammalian skeletal muscles. Physiol. Rev. 52: 129–197, 1972.
 58. Close, R., and J. F. Y. Hoh. Force: velocity properties of kitten muscles. J. Physiol. London 192: 815–822, 1967.
 59. Close, R., and J. F. Y. Hoh. Influence of temperature on isometric contractions of rat skeletal muscles. Nature London 217: 1179–1180, 1968.
 60. Cobb, S., and A. Forbes. Electromyographic studies of muscular fatigue in man. Am. J. Physiol. 65: 234–251, 1923.
 61. Cooper, S., and J. C. Eccles. The isometric responses of mammalian muscles. J. Physiol. London 69: 377–385, 1930.
 62. Creese, R., J. L. D'Silva, and S. E. E. Hashish. Inulin space and fibre size of stimulated rat muscle. J. Physiol. London 127: 525–532, 1955.
 63. Danon, J., W. S. Druz, N. B. Goldberg, and J. T. Sharp. Function of the isolated paced diaphragm and the cervical accessory muscles in C‐1 quadriplegics. Am. Rev. Respir. Dis. 119: 909–919, 1979.
 64. Danon, J., H. C. Fishman, J. Lin, M. Sharif, W. S. Druz, and J. T. Sharp. Measurements of diaphragmatic length in normal individuals and in patients with C.O.P.D. (Abstract). Chest 70: 423, 1976.
 65. Davies, A. S., and H. M. Gunn. Histochemical fibre types in the mammalian diaphragm. J. Anat. 112: 41–60, 1972.
 66. De Luca, C. J., and W. J. Forrest. An electrode for recording single motor unit activity during strong muscle contractions. IEEE Trans. Biomed Eng. 19: 367–372, 1972.
 67. De Troyer, A., and J. C. Yernault. Inspiratory muscle force in normal subjects and patients with interstitial lung disease. Thorax 35: 92–100, 1980.
 68. De Vries, H. A. EMG fatigue curves in postural muscles. A possible etiology for idiopathic low back pain. Am. J. Phys. Med. 17: 175–181, 1968.
 69. Doyle, A. M., and R. F. Mayer. Studies of the motor unit of the cat. Bull. Sch. Med. Univ. Md. 54: 11–17, 1969.
 70. Draper, M. H., P. Ladefoget, and D. Whitteridge. Respiratory muscles in speech. J. Speech Hear. Res. 2: 16–27, 1959.
 71. Druz, W. S., and J. T. Sharp. Activity of respiratory muscles in upright and recumbent humans. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 51: 1552–1561, 1981.
 72. Ebashi, S., M. Endo, and I. Ohtsuki. Control of muscle contraction. Q. Rev. Biophys. 2: 351–384, 1969.
 73. Ebashi, S., K. Maruyama, and M. Endo (editors). Muscle Contraction. Its Regulatory Mechanisms. Berlin: Springer‐Verlag, 1980.
 74. Eberstein, A., and J. Goodgold. Slow and fast twitch fibers in human skeletal muscle. Am. J. Physiol. 215: 535–541, 1968.
 75. Edgerton, V. R., L. Cerchman, and R. Carrow. Histochemical changes in rat skeletal muscle after exercises. Exp. Neurol. 24: 110–123, 1969.
 76. Edgerton, V. R., and D. R. Simpson. The intermediate muscle fiber of rats and guinea pigs. J. Histochem. Cytochem. 17: 828–838, 1969.
 77. Edgerton, V. R., and D. R. Simpson. Dynamic and metabolic relationships in the rat extensor digitorum longus muscle. Exp. Neurol. 30: 374–376, 1971.
 78. Edström, L., and E. Kugelberg. Histological composition, distribution of fibers and fatigability of single motor units. J. Neurol. Neurosurg. Psychiatry 31: 424–433, 1968.
 79. Edwards, R. H. T. Physiological analysis of skeletal muscle weakness and fatigue. Clin. Sci. Mol. Med. 54: 463–470, 1978.
 80. Edwards, R. H. T., D. K. Hill, D. A. Jones, and P. A. Merton. Fatigue of long duration in human skeletal muscle after exercise. J. Physiol. London 272: 769–778, 1977.
 81. Edwards, R. H. T., A. Young, G. P. Hosking, and D. A. Jones. Human skeletal muscle function: description of tests and normal values. Clin. Sci. Mol. Med. 52: 283–290, 1977.
 82. Endo, M. Entry of fluorescent dyes into the sarcotubular system of the frog muscle. J. Physiol. London 185: 224–238, 1966.
 83. Engel, W. K. The essentiality of histo‐ and cytochemical studies of skeletal muscle in the investigation of neuromuscular disease. Neurology 12: 778–784, 1962.
 84. Essén, B., E. Jansson, J. Hendriksson, A. W. Taylor, and B. Saltin. Metabolic characteristics of fiber types in human skeletal muscle. Acta Physiol. Scand. 95: 153–165, 1975.
 85. Fadell, E. J., A. D. Richman, and W. W. Ward. Fatty infiltration of respiratory muscles in the Pickwickian syndrome. N. Engl. J. Med. 266: 861–863, 1962.
 86. Fanburg, B. L., D. B. Drachman, D. Moll, and S. I. Roth. Calcium transport in isolated sarcoplasmic reticulum during muscle maturation. Nature London 218: 962–964, 1968.
 87. Farkas, G. A., and C. Roussos. Adaptability of the hamster diaphragm to exercise and/or emphysema. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 53: 1263–1272, 1982.
 88. Faulkner, J. A., L. C. Maxwell, D. A. Brook, and D. A. Lieberman. Adaptation of guinea pig plantaris muscle fibers to endurance training. Am. J. Physiol. 221: 291–297, 1971.
 89. Faulkner, J. A., L. C. Maxwell, and D. A. Lieberman. Histochemical characteristics of muscle fibers from trained and detrained guinea pigs. Am. J. Physiol. 222: 836–840, 1972.
 90. Faulkner, J. A., L. C. Maxwell, G. L. Ruff, and T. P. White. The diaphragm as muscle. Contractile properties. Am. Rev. Respir. Dis. 119: 89–92, 1979.
 91. Feinstein, B., B. Lindegård, E. Nyman, and G. Wohlfart. Morphological studies of motor units in normal human muscles. Acta Anat. 23: 127–142, 1955.
 92. Fenn, W. O. A comparison of respiratory and skeletal muscles. In: Perspectives in Biology, edited by C. F. Cori, V. G. Foglia, L. F. Leloir, and S. Ochoa. Amsterdam: Elsevier, 1963, p. 293–300.
 93. Fenn, W. O., and B. S. Marsh. Muscular force at different speeds of shortening. J. Physiol. London 85: 277–297, 1935.
 94. Fex, S. “Trophic” influence of implanted fast nerve on innervated slow muscle. Physiol. Bohemoslov. 18: 205–208, 1969.
 95. Fex, S., and B. Sonesson. Histochemical observations after implantation of a “fast” nerve into an innervated mammalian “slow” muscle. Acta Anat. 77: 1–10, 1970.
 96. Flear, C. T. G., R. F. Crampton, and D. M. Matthews. An in vitro method for the determination of the inulin space of skeletal muscle with observations on the composition of human muscle. Clin. Sci. 19: 483–493, 1960.
 97. Franzini‐Armstrong, C., and K. R. Porter. Sarcolemmal invaginations constituting the T system in fish muscle fibers. J. Cell Biol. 22: 675–696, 1964.
 98. Gabel, L. P., C. Carson, and E. Vance. Active state of muscle and the second and third derivatives of twitch tension. Am. J. Physiol. 214: 1025–1030, 1968.
 99. Gath, I., and E. Stålberg. Frequency and time domain characteristics of single muscle fibre action potentials. Electromyogr. Clin. Neurophysiol. 39: 371–376, 1975.
 100. Gauthier, G. F. On the relationship of ultrastructural and cytochemical features to color in mammalian skeletal muscle. Z. Zellforsch. Mikrosk. Anat. 95: 462–482, 1969.
 101. Gauthier, G. F., and H. A. Padykula. Cytological studies of fiber types in skeletal muscle. A comparative study of the mammalian diaphragm. J. Cell Biol. 28: 333–354, 1966.
 102. Geddes, L. A. Electrodes and the Measurement of Bioelectric Events. New York: Wiley‐Interscience, 1972.
 103. Geffen, L. B. Optimum length for contraction of rat circulated limb muscles. Arch. Int. Physiol. 72: 825–834, 1964.
 104. Glebovskii, V. D. The contractile properties of the respiratory muscles in adult and new‐born animals. Sechenov. Physiol. J. USSR 47: 8–15, 1961.
 105. Goffart, M., O. Holmes, and Z. M. Bacq. Some mechanical properties of skeletal muscles in the sloth (Choloepus hoffmanni Peters). Arch. Int. Physiol. 70: 103–106, 1962.
 106. Goffart, M., and J. M. Ritchie. The effect of adrenaline on the contraction of mammalian skeletal muscles. J. Physiol. London 116: 357–371, 1952.
 107. Goldspink, G. An attempt at estimating extrafiber fluid in small skeletal muscles by a simple physical method. Can. J. Physiol. Pharmacol. 44: 765–775, 1966.
 108. Goldspink, G. Sarcomere length during postnatal growth of mammalian muscle fibers. J. Cell Sci. 3: 539–548, 1968.
 109. Gollnick, P. D., and D. W. King. Effect of exercise and training on mitochondria of rat skeletal muscle. Am. J. Physiol. 216: 1502–1509, 1969.
 110. Gordon, A. M., A. F. Huxley, and F. J. Julian. The variation in isometric tension with sarcomere length in vertebrate muscle fibres. J. Physiol. London 184: 170–192, 1966.
 111. Gordon, E. E., K. Kowalski, and M. Fritts. Protein changes in quadriceps muscle of rat with competitive exercise. Arch. Phys. Med. Rehabil. 48: 296–303, 1966.
 112. Green, M., J. Mead, and T. A. Sears. Muscle activity during chest wall restriction and positive pressure breathing in man. Respir. Physiol. 35: 283–300, 1978.
 113. Grimby, G., M. Goldman, and J. Mead. Respiratory muscle action inferred from rib cage and abdominal V‐P partitioning. J. Appl. Physiol. 41: 739–751, 1976.
 114. Gross, D., A. Grassino, W. R. D. Ross, and P. T. Macklem. Electromyogram pattern of diaphragmatic fatigue. J. Appl. Physiol: Respirat. Environ. Exercise Physiol. 46: 1–7, 1979.
 115. Guth, L., and F. J. Samaha. Qualitative differences between actomyosin ATPase of slow and fast mammalian muscle. Exp. Neurol. 25: 138–152, 1969.
 116. Håkansson, C. H. Conduction velocity and amplitude of the action potential as related to circumference in the isolated fiber of frog muscle. Acta Physiol. Scand. 37: 14–34, 1956.
 117. Hall‐Craggs, E. C. B. The contraction times and enzyme activity of two rabbit laryngeal muscles. J. Anat. 102: 241–255, 1968.
 118. Hartree, W., and A. V. Hill. The nature of the isometric twitch. J. Physiol. London 55: 389–411, 1921.
 119. Heistracher, P., and C. C. Hunt. The relation of membrane changes to contraction in twitch muscle fibres. J. Physiol. London 201: 589–611, 1969.
 120. Henneman, E., and C. B. Olson. Relations between structure and function in the design of skeletal muscle. J. Neurophysiol. 28: 581–598, 1965.
 121. Hill, A. V. The heat of shortening and dynamic constants of muscle. Proc. R. Soc. London Ser. B 126: 136–195, 1938.
 122. Hill, A. V. The abrupt transition from rest to activity in muscle. Proc. R. Soc. London Ser. B 136: 399–420, 1949.
 123. Hill, A. V. The dimensions of animals and their muscular dynamics. Sci. Prog. London 38: 209–230, 1950.
 124. Hill, A. V. The series elastic component of muscle. Proc. R. Soc. London Ser. B 137: 273–280, 1950.
 125. Hill, A. V. Thermodynamics of muscle. Nature London 167: 377–380, 1951.
 126. Hill, A. V. The transition from rest to full activity in muscle: the velocity of shortening. Proc. R. Soc. London Ser. B 138: 329–338, 1951.
 127. Hill, A. V. The “plateau” of full activity during a muscle twitch. Proc. R. Soc. London Ser. B 141: 498–503, 1953.
 128. Hill, A. V. The design of muscles. Br. Med. Bull. 12: 165–166, 1956.
 129. Hill, A. V. Production and absorption of work by muscle. Science 131: 897–903, 1960.
 130. Hill, D. K. The space accessible to albumin within the striated muscle fibre of the toad. J. Physiol. London 175: 275–294, 1964.
 131. Hofmann, W. W., W. Alston, and G. Rowe. A study of individual neuromuscular junctions in myotonia. Electroencephalogr. Clin. Neurophysiol. 21: 521–537, 1966.
 132. Holland, D. L., and S. V. Perry. The adenosine triphosphatase and calcium ion‐transporting activities of the sarcoplasmic reticulum of developing muscle. Biochem. J. 114: 161–170, 1969.
 133. Holloszy, J. O. Biochemical adaptations in muscle. J. Biol. Chem. 242: 2278–2282, 1967.
 134. Huidobro, F., and E. Amenabar. Effectiveness of caffeine (1,3,7 trimethylxanthine) against fatigue. J. Pharmacol. Exp. Ther. 84: 82–92, 1945.
 135. Huxley, A. F. Muscular contraction. J. Physiol. London 243: 1–43, 1974.
 136. Huxley, H. E. Evidence for continuity between central elements of the triads and extracellular space in frog sartorius muscle. Nature London 202: 1067–1071, 1964.
 137. Hyatt, R. E., and R. E. Flath. Relationship of air flow to pressure during maximal respiratory effort in man. J. Appl. Physiol. 21: 477–482, 1966.
 138. Jagendorf‐Elfvin, M. Ultrastructure of the contraction‐relaxation cycle of glycerinated rabbit psoas muscle. II. The ulrastructure of glycerinated fibers relaxed in EDTA and ATP following ATP‐induced contraction. J. Ultrastruct. Res. 17: 379–400, 1967.
 139. Jewell, B. R., and D. R. Wilkie. An analysis of the mechanical components in frog's striated muscle. J. Physiol. London 143: 515–540, 1958.
 140. Jewell, B. R., and D. R. Wilkie. The mechanical properties of relaxing muscle. J. Physiol. London 152: 30–47, 1960.
 141. Jöbsis, F. F., and M. J. O'Connor. Calcium release and reabsorption in the sartorius muscle of the toad. Biochem. Biophys. Res. Commun. 25: 246–252, 1966.
 142. Johnson, M. A., J. Polgar, D. Weightman, and D. Appleton. Data on the distribution of fiber types in thirty six human muscles. An autopsy study. J. Neurol. Sci. 18: 111–129, 1973.
 143. Jurna, I., W. Rummel, and H. Schäfer. Die abfallende Phase des aktiven Zustandes des Tibialis anterior, Gastrocnemius und Soleus der Katz und ihre Beeinflussung durch Dehnung und Sympathicomimetica. Pfluegers Arch. Gesamte Physiol. Menschen Tiere 277: 513–522, 1963.
 144. Kadefors, R., E. Kaiser, and I. Petersén. Dynamic spectrum analysis of myopotentials with special reference to muscle fatigue. Electromyogr. Clin. Neurophysiol. 8: 39–74, 1968.
 145. Kaiser, E., and I. Peterśen. Frequency analysis of action potentials during tetanic contraction (Abstract). Electroencephalogr. Clin. Neurophysiol. 14: 955, 1962.
 146. Karpati, G., and W. K. Engel. Neuronal trophic function. Arch. Neurol. 17: 542–545, 1967.
 147. Katz, B. The relation between force and speed in muscular contraction. J. Physiol. London 96: 45–64, 1939.
 148. Keens, T. G., A. C. Bryan, H. Levison, and C. D. Ianuzzo. Developmental pattern of muscle fiber types in human ventilatory muscles. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 44: 909–913, 1978.
 149. Kim, M. J., W. S. Druz, J. Danon, W. Machnach, and J. T. Sharp. Mechanics of the canine diaphragm. J. Appl. Physiol. 41: 369–382, 1976.
 150. Kim, M. J., W. S. Druz, W. Machnach, and J. T. Sharp. Relationship of direct diaphragmatic EMG to muscle length in a canine diaphragm strip preparation (Abstract). Physiologist 23 (4): 2, 1980.
 151. Kim, M. J., W. S. Druz, W. Machnach, and J. T. Sharp. Muscle fatigue in a canine diaphragmatic strip with intact nerve and blood supply (Abstract). Am. Rev. Respir. Dis. 123: 201, 1981.
 152. Kondo, S. Anthropological study on human posture and locomotion. J. Fac. Sci. Univ. Tokyo Sect. 2: 189–260, 1960.
 153. Kowalski, K., E. E. Gordon, A. Martinez, and J. Adamek. Changes in enzyme activities of various muscle fiber types in rat induced by different exercises. J. Histochem. Cytochem. 17: 601–607, 1969.
 154. Kugelberg, E., and L. Edström. Differential histochemical effects of muscle contractions on phosphorylase and glycogen in various types of fibres: relation to fatigue. J. Neurol. Neurosurg. Psychiatry 31: 415–423, 1968.
 155. Leifer, L. J. Characterization of Single Muscle Fiber Discharge During Voluntary Isometric Contraction of the Biceps Brachii in Man. Stanford, CA: Stanford Univ., 1969. PhD thesis.
 156. Lewis, D. M., and J. C. Luck. Effect of initial length on the tension developed by motor units in flexor hallucis longus muscle of the cat (Abstract). J. Physiol. London 197: 42P–43P, 1968.
 157. Lieberman, D. A., J. A. Faulkner, A. B. Craig, Jr., and L. C. Maxwell. Performance and histochemical composition of guinea pig and human diaphragm. J. Appl. Physiol. 34: 233–237, 1973.
 158. Lindström, L. R. On the Frequency Spectrum of EMG Signals. Göteborg, Sweden: Chalmers Univ. of Technology, Res. Lab. Med. Electron., 1970. (Tech. Rep. 7.)
 159. Lindström, L. R. A Model Describing the Power Spectrum of Myoelectric Signals. Part I. Single Fibre Signal. Göteborg, Sweden: Chalmers Univ. of Technology, Res. Lab. Med. Electron., 1974. (Tech. Rep. 5.)
 160. Lindström, L., R. Magnusson, and I. Petersén. Muscle load influence on myoelectric signal characteristics. Scand. J. Rehabil. Med. 3, Suppl.: 127–148, 1974.
 161. Ling, G. N., and M. H. Kromash. The extracellular space of voluntary muscle tissues. J. Gen. Physiol. 50: 677–694, 1967.
 162. Lippold, O. C. J. The relation between integrated action potentials in human muscle and its isometric tension. J. Physiol. London 117: 492–499, 1952.
 163. Lippold, O. C. J., Redfearn, J. W. T., and J. Vuco. The rhythmical activities of groups of motor units in the voluntary contraction of muscle. J. Physiol. London 137: 473–487, 1957.
 164. Lloyd, A. J. Surface electromyography during sustained isometric contractions. J. Appl. Physiol. 30: 713–719, 1971.
 165. Lopata, M., R. A. Freilich, E. Önal, J. Pearle, and R. V. Lourenço. Ventilatory control and the obesity‐hypoventilation syndrome. Am. Rev. Respir. Dis. 119: 165–168, 1979.
 166. Lourenço, R. V., N. S. Cherniack, J. R. Malm, and A. P. Fishman. Nervous output from the respiratory center during obstructed breathing. J. Appl. Physiol. 21: 527–533, 1966.
 167. Lourenço, R. V., C. M. Turino, L. A. D. Davidson, and A. P. Fishman. The regulation of ventilation in diffuse pulmonary fibrosis. Am. J. Med. 38: 199–216, 1965.
 168. Luff, A. R. Dynamic properties of the inferior rectus, extensor digitorum longus, diaphragm and soleus muscles of the mouse. J. Physiol. London 313: 161–171, 1981.
 169. Luff, A. R., and H. L. Atwood. Developmental changes in the sarcoplasmic reticulum and transverse tubular system in skeletal muscles of the mouse. J. Gen. Physiol. 57: 243–244, 1971.
 170. Lynne‐Davies, P., R. Fine, and S. Enjeti. Effects of neuromuscular disease on frequency spectrum of sternocleidomastoid muscle (Abstract). Am. Rev. Respir. Dis. 123: 193, 1981.
 171. MacPherson, L., and D. R. Wilkie. Duration of the active state in a muscle twitch. J. Physiol. London 124: 292–299, 1954.
 172. Marshall, R. Relationships between stimulus and work of breathing at different lung volumes. J. Appl. Physiol. 17: 917–921, 1962.
 173. Maxwell, L. C., J. A. Faulkner, and D. A. Lieberman. Histochemical manifestations of age and endurance training in skeletal muscle fibers. Am. J. Physiol. 224: 356–361, 1973.
 174. McCrorey, H. L., H. H. Gale, and N. R. Alpert. Mechanical properties of cat tenuissimus muscle. Am. J. Physiol. 210: 114–120, 1966.
 175. McCully, K. K., G. Farkas, and J. A. Faulkner. Length‐tension relationship and mammalian diaphragm muscles in vitro (Abstract). Physiologist 23 (4): 96, 1980.
 176. Merton, P. A. Voluntary strength and fatigue. J. Physiol. London 123: 553–564, 1954.
 177. Merton, P. A. Problems of muscular fatigue. Br. Med. Bull. 12: 219–221, 1956.
 178. Mognoni, P., F. Saibene, G. Sant'Ambrogio, and E. Agostoni. Dynamics of the maximal contraction of the respiratory muscles. Respir. Physiol. 4: 193–202, 1968.
 179. Monges, H., J. Salducci, and B. Naudy. Dissociation between the electrical activity of the diaphragmatic dome and crura and muscular fibers during esophageal distension vomiting and eructation. J. Physiol. Paris 74: 541–554, 1978.
 180. Mortimer, J. T., R. Magnusson, and I. Petersén. Conduction velocity in ischemic muscle: effect on EMG frequency spectrum. Am. J. Physiol. 219: 1324–1329, 1970.
 181. Moxham, J., C. M. Wiles, D. Newham, and R. H. T. Edwards. Sternomastoid function and fatigue in man. Clin. Sci. Mol. Med. 59: 463–468, 1980.
 182. Muller, N., A. C. Bryan, and N. Zamel. Tonic inspiratory muscle activity as a cause of hyperinflation in asthma. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 50: 279–282, 1981.
 183. Muller, N., G. Volgyesi, L. Becker, M. H. Bryan, and A. C. Bryan. Diaphragmatic muscle tone. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 47: 279–284, 1979.
 184. Nastuk, W. L., and A. L. Hodgkin. The electrical activity of single muscle fibers. J. Cell. Comp. Physiol. 35: 39–73, 1950.
 185. O'Donnell, R. D., R. Rapp, J. Berkout, and W. R. Adey. Autospectral and coherence patterns from two locations in the contracting biceps. Electromyogr. Clin. Neurophysiol. 13: 259–269, 1973.
 186. Ogata, T., T. Kawashima, and A. Nishiyama. Histochemical demonstration of three types of muscle fibers of the intercostal muscles. A study on oxidative enzymes. Acta Med. Okayama 17: 257–259, 1963.
 187. Ogata, T., and M. Mori. Histochemical study of oxidative enzymes in vertebrate muscles. J. Histochem. Cytochem. 12: 171–182, 1964.
 188. Olson, C. B., and C. P. Swett. A functional and histochemical characterization of motor units in a heterogeneous muscle (flexor digitorum longus) of the cat. J. Comp. Neurol. 128: 475–497, 1966.
 189. Padykula, H. A., and G. F. Gauthier. Morphological and cytochemical characteristics of fiber types in normal mammalian skeletal muscle. In: Exploratory Concepts in Muscular Dystrophy and Related Disorders, edited by A. T. Milhorat. Amsterdam: Excerpta Med., 1967, p. 117–128.
 190. Page, S. G. Structure and some contractile properties of fast and slow muscles of the chicken. J. Physiol. London 205: 131–145, 1969.
 191. Page, S. G., and H. E. Huxley. Filament lengths in striated muscle. J. Cell Biol. 19: 369–390, 1963.
 192. Parmley, W. W., L. A. Yeatman, and E. H. Sonnenblick. Differences between isotonic and isometric force‐velocity relations in cardiac and skeletal muscle. Am. J. Physiol. 219: 546–550, 1970.
 193. Pengelly, L. D., A. M. Alderson, and J. Milic‐Emili. Mechanics of the diaphragm. J. Appl. Physiol. 30: 797–805, 1971.
 194. Perry, S. V., and D. T. Hartshorne. The proteins of developing muscle. In: The Effect of Use and Disuse in Neuromuscular Functions, edited by E. Gutmann and P. Hnik. Prague: Czech. Acad. Sci., 1963, p. 491.
 195. Peter, J. B., R. J. Barnard, V. R. Edgerton, C. A. Gillespie, and K. E. Stempel. Metabolic profiles of three fiber types of skeletal muscle in guinea pigs and rabbits. Biochemistry 11: 2627–2633, 1972.
 196. Petersén, I., and E. Kugelberg. Duration and form of action potential in the normal human muscle. J. Neurol. Neurosurg. Psychiatry 12: 124–128, 1949.
 197. Petit, J. M., G. Milic‐Emili, and L. Delhez. Role of the diaphragm in breathing in conscious normal man: an electromyographic study. J. Appl. Physiol. 15: 1101–1106, 1960.
 198. Rack, P. M. H., and D. R. Westbury. The effects of length and stimulus rate on tension in the isometric cat soleus muscle. J. Physiol. London 204: 443–460, 1969.
 199. Ralston, H. J. Uses and limitations of electromyography in the quantitative study of skeletal muscle function. Am. J. Orthod. 47: 521–530, 1961.
 200. Ralston, H. J., V. T. Inman, L. A. Strait, and M. D. Shaffrath. Mechanics of human isolated voluntary muscle. Am. J. Physiol. 151: 612–620, 1947.
 201. Ralston, H. J., F. N. Todd, and V. T. Inman. Comparison of electrical activity and duration of tension in the human rectus femoris muscle. Electromyogr. Clin. Neurophysiol. 16: 277–286, 1976.
 202. Raper, A. J., W. T. Thompson, Jr., W. Shapiro, and J. L. Patterson, Jr. Scalene and sternomastoid muscle function. J. Appl. Physiol. 21: 497–502, 1966.
 203. Riley, D. A., and A. J. Berger. A regional histochemical and electromyographic analysis of the cat respiratory diaphragm. Exp. Neurol. 66: 636–649, 1979.
 204. Ritchie, J. M. The relation between force and velocity of shortening in rat muscle. J. Physiol. London 123: 633–639, 1954.
 205. Ritchie, J. M. The effect of nitrate on the active state of muscle. J. Physiol. London 126: 155–168, 1954.
 206. Rochester, D. F., and Y. Enson. Current concepts in the pathogenesis of the obesity‐hypoventilation syndrome. Mechanical and circulatory factors. Am. J. Med. 57: 402–420, 1974.
 207. Romanul, F. C. A. Enzymes in muscle. I. Histochemical studies of enzymes in individual muscle fibers. Arch. Neurol. 11: 355–369, 1964.
 208. Rosenfalck, P. Intra‐ and Extracellular Potential Fields of Active Nerve and Muscle Fibers. Copenhagen: Acad. Forlag, 1969.
 209. Rossier, P. M., H. J. Nieporent, H. Pipberger, and Z. Kalin. Electromyographic studies on respiratory muscle function in normal volunteers. Z. Gesamte Exp. Med. 127: 39–52, 1956.
 210. Rowe, R. W. D. The effect of hypertrophy on the properties of skeletal muscle. Comp. Biochem. Physiol. 28: 1449–1453, 1969.
 211. Rüdel, R., and S. R. Taylor. Aequorin luminescence during contraction of amphibian skeletal muscle (Abstract). J. Physiol. London 233: 5P–6P, 1973.
 212. Ruedi, L. Some observations on the histology and function of the larynx. J. Laryngol. Otol. 73: 1–20, 1959.
 213. Saltin, B., J. Henriksson, E. Nygaard, P. Andersen, and E. Jansson. Fiber types and metabolic potentials of skeletal muscles in sedentary men and endurance runners. Ann. NY Acad. Sci. 301: 3–29, 1977.
 214. Samaha, F. J., L. Guth, and R. W. Alhers. Differences between slow and fast muscle myosin. Adenosine triphosphatase activity and release of associated proteins by p‐chloromercuriphenylsulfonate. J. Biol. Chem. 245: 219–224, 1970.
 215. Sandow, A. Excitation‐contraction coupling in skeletal muscle. Pharmacol. Rev. 17: 265–320, 1965.
 216. Sandow, A. Skeletal muscle. Annu. Rev. Physiol. 32: 87–138, 1970.
 217. Sant'Ambrogio, G., and F. Saibene. Contractile properties of the diaphragm in some mammals. Respir. Physiol. 10: 349–357, 1970.
 218. Sato, M. Frequency components of the electromyogram led with the bipolar surface electrodes. J. Anthropol. Soc. Nippon 72: 14–28, 1964.
 219. Scherrer, J., A. Bourguignon, and R. Marty. Évaluation electromyographique du travail statique. J. Physiol. Paris 49: 376–378, 1957.
 220. Scherrer, J., and H. Monod. Le travail musculaire local et la fatigue chez l'homme. J. Physiol. Paris 52: 419–501, 1960.
 221. Schweitzer, T. W., J. W. Fitzgerald, J. A. Bowden, and P. Lynne‐Davies. Spectral analysis of human inspiratory diaphragmatic electromyograms. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 46: 152–165, 1979.
 222. Schwieler, G. H. Respiratory regulation during postnatal development in cats and rabbits and some of its morphologic substrate. Acta Physiol. Scand. Suppl. 304: 1–123, 1968.
 223. Senay, L. C., Jr., and B. A. Schottelius. Effect of ischemia on the length‐tension diagram of mammalian skeletal muscle. Am. J. Physiol. 188: 113–117, 1957.
 224. Sexton, A. W. Isometric tension of glycerinated muscle fibers following adrenalectomy. Am. J. Physiol. 212: 313–316, 1967.
 225. Sexton, A. W., and J. W. Gersten. Isometric tension differences in fibers of red and white muscles. Science 157: 199, 1967.
 226. Sharp, J. T., J. Danon, W. S. Druz, N. B. Goldberg, H. Fishman, and W. Machnach. Respiratory muscle function in patients with chronic obstructive lung disease: its relationship to disability and to respiratory failure. Am. Rev. Respir. Dis. 110, Suppl. 6: 154–167, 1974.
 227. Sharp, J. T., W. S. Druz, T. Moisan, J. Foster, and W. Machnach. Postural relief of dyspnea in severe COPD. Am. Rev. Respir. Dis. 122: 201–211, 1980.
 228. Sharp, J. T., N. B. Goldberg, W. S. Druz, and J. Danon. Relative contributions of rib cage and abdomen to breathing in normal subjects. J. Appl. Physiol. 39: 608–618, 1975.
 229. Sharp, J. T., N. B. Goldberg, W. S. Druz, H. C. Fishman, and J. Danon. Thoracoabdominal motion in chronic obstructive lung disease. Am. Rev. Respir. Dis. 115: 47–56, 1977.
 230. Sjöstrand, F. S., and M. Jagendorf‐Elfvin. Ultrastructural studies of the contraction‐relaxation cycle of glycerinated rabbit psoas muscle. I. The ultrastructure of glycerinated fibers contracted by treatment with ATP. J. Ultrastruct. Res. 17: 348–378, 1967.
 231. Snider, G. L., and C. B. Sherter. A one‐year study of the evolution of elastase‐induced emphysema in hamsters. J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 43: 721–729, 1977.
 232. Sréter, F. A., J. C. Seidel, and J. Gergely. Studies on myosin from red and white skeletal muscle of the rabbit. I. Adenosine triphosphatase activity. J. Biol. Chem. 241: 5772–5776, 1966.
 233. Stålberg, E. Propagation velocity in human muscle fibres in situ. Acta Physiol. Scand. Suppl. 287: 1–12, 1966.
 234. Stålberg, E., and J. Ekstedt. Single fiber EMG and micro‐physiology of the motor unit in normal and diseased muscle. In: New Developments in Electromyography and Clinical Neurophysiology, edited by J. E. Desmedt. Basel: Karger, 1973, p. 113–129.
 235. Stålberg, E., M. S. Schwartz, B. Thiele, and H. H. Schiller. The normal motor unit in man. J. Neurol. Sci. 27: 291–301, 1976.
 236. Stanley, D. W., and G. W. De Villafranca. Isometric contraction in glycerinated skeletal muscle of horseshoe crab and rabbit. I. Relation of tension to muscle fiber dimensions. Comp. Biochem. Physiol. 36: 263–270, 1970.
 237. Steele, R. H., and B. E. Heard. Size of the diaphragm in chronic bronchitis. Thorax 28: 55–60, 1973.
 238. Stein, J. M., and H. A. Padykula. Histochemical classification of individual skeletal muscle fibers of the rat. Am. J. Anal 110: 103–124, 1962.
 239. Stolov, W. C., and T. G. Weilepp. Passive length‐tension relationship of intact muscle, epimysium and tendon in normal and denervated gastrocnemius of the rat. Arch. Phys. Med. Rehabil. 47: 612–620, 1966.
 240. Tabary, J. C., C. Tabary, C. Tardieu, G. Tardieu, and G. goldspink. Physiological and structural changes in the cat's soleus muscle due to immobilization at different lengths by plaster casts. J. Physiol. London 224: 231–244, 1972.
 241. Thompson, W. T., Jr., J. L. Patterson, Jr., and W. Shapiro. Observations on the scalene respiratory muscles. Arch. Intern. Med. 113: 856–865, 1964.
 242. Thurlbeck, W. M. Diaphragm and body weight in emphysema. Thorax 33: 483–487, 1978.
 243. Trayer, I. P., and S. V. Perry. Evidence for differences between foetal and adult myosins (Abstract). Biochem. J. 97: 36P, 1965.
 244. Trayer, I. P., and S. V. Perry. The myosin of developing skeletal muscle. Biochem. Z. 345: 87–100, 1966.
 245. Truong, X. T., B. J. Wall, and S. M. Walker. Effects of temperature on isometric contraction of rat muscle. Am. J. Physiol. 207: 393–396, 1964.
 246. Viljanen, A. A. The relation between the electrical and mechanical activity of human intercostal muscles during voluntary inspiration. Acta Physiol. Scand. Suppl. 296: 1–61, 1967.
 247. Viljanen, A. A., H. Poppins, R. M. Bergströmer, and M. Hakumäki. Electrical and mechanical activity in human respiratory muscles. Acta Neurol. Scand. Suppl. 13: 237–239, 1964.
 248. Walker, S. M. The relation of stretch and of temperature to contraction in skeletal muscle. Am. J. Phys. Med. Rehabil. 39: 234–258, 1960.
 249. Walker, S. M., and G. R. Schrodt. Filament lengths and distribution of staining material in the I bands of rat skeletal muscle. Am. J. Phys. Med. Rehabil. 48: 178–192, 1969.
 250. Walker, S. M., G. R. Schrodt, and M. Bingham. Electron microscope study of the sarcoplasmic reticulum at the Z line level in skeletal muscle fibers of fetal and newborn rats. J. Cell Biol. 39: 469–475, 1968.
 251. Wilkie, D. R. Relation between force and velocity in human muscle. J. Physiol. London 110: 249–280, 1950.
 252. Wilkie, D. R. The mechanical properties of muscle. Br. Med. Bull. 12: 177–182, 1956.
 253. Yellin, H., and L. Guth. The histochemical classification of muscle fibers. Exp. Neurol. 26: 424–432, 1970.

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John T. Sharp, Robert E. Hyatt. Mechanical and Electrical Properties of Respiratory Muscles. Compr Physiol 2011, Supplement 12: Handbook of Physiology, The Respiratory System, Mechanics of Breathing: 389-414. First published in print 1986. doi: 10.1002/cphy.cp030323