Passive extensibility of skeletal muscle: review of the literature with clinical implications


      The purpose of this article was to review the literature on passive extensibility of skeletal muscle with reference to its anatomic and physiologic properties, mechanisms of adaptations and clinical implications. Studies with animal muscles have shown that passive extensibility is influenced by the size (mass) and length of muscle fibers, and the amount and arrangement of the connective tissues of the muscle belly. The resistance to passive lengthening is influenced by the readily adaptable amount of muscle tissue, including the contractile proteins and the non-contractile proteins of the sarcomere cytoskeletons. The relationship of adaptable changes in the muscle tissue and in the extracellular connective tissues remains unclear. Muscle length adaptations result from changes in the number of sarcomeres in series, which depend on the imposed length of muscles, not on the level of muscle activation and tension. This mechanism of muscle length adaptations, termed ‘myogenic’, has not been demonstrated in human muscles, but it has been intimated by therapeutic lengthening studies showing that both healthy and neurologically impaired human muscles can undergo increased length adaptations in the presence of muscle activations. Studies have suggested that optimal muscle function is probably achieved by increasing muscle length, length extensibility, passive elastic stiffness, mass and strength, but additional studies are needed to investigate these relationships, particularly for aged muscles and for muscles affected by clinical disorders, disease and injury. Such studies could contribute to the development of new intervention strategies designed to promote the passive muscle extensibility that enhances total muscle function, and ultimately improves the ability to complete functional activities and excel in athletic performances.


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        • Brodie T.G.
        The extensibility of muscle.
        J Anat Physiol. 1895; 29: 367-388
        • Haycraft J.B.
        The elasticity of animal tissues.
        J Physiol. 1904; 31: 392-409
        • Banus M.G.
        • Zetlin A.M.
        The relation of isometric tension to length in skeletal muscle.
        J Cell Comp Physiol. 1938; 12: 403-420
        • Ramsey R.W.
        • Street S.F.
        The isometric length–tension diagram of isolated skeletal muscle fibers of the frog.
        J Cell Comp Physiol. 1940; 15: 11-34
        • Stolov W.C.
        • Weilepp T.G.
        Passive length–tension relationship of intact muscle, epimysium, and tendon in normal and denervated gastrocnemius of the rat.
        Arch Phys Med Rehabil. 1966; 47: 612-620
        • Tabary J.C.
        • Tabary C.
        • Tardieu C.
        • Tardieu G.
        • Goldspink G.
        Physiological and structural changes in the cat’s soleus muscle due to immobilization at different lengths by plaster casts.
        J Physiol. 1972; 224: 231-244
        • Tabary J.C.
        • Tardieu C.
        • Tardieu G.
        • Tabary C.
        • Gagnard L.
        Functional adaptation of sarcomere number of normal cat muscle.
        J Physiol (Paris). 1976; 72: 277-291
        • Williams P.E.
        • Goldspink G.
        Changes in sarcomere length and physiological properties in immobilized muscle.
        J Anat (London). 1978; 127: 459-468
        • Evans C.L.
        • Hill A.V.
        The relation of length to tension development and heat production on contraction in muscle.
        J Physiol. 1914; 49: 10-16
        • Gordon A.M.
        • Huxley A.F.
        • Julian F.J.
        The variation in isometric tension with sarcomere length in vertebrate muscle fibers.
        J Physiol. 1966; 184: 170-192
      1. Astrand P, Rodauhl K. Textbook of work physiology. 3rd ed. New York: McGraw-Hill, 1986. p. 41

        • Halar E.M.
        • Stolov W.C.
        • Venkatesh B.
        • Brozovivh F.V.
        • Harley J.D.
        Gastrocnemius muscle belly and tendon length in stroke patients and able-bodied persons.
        Arch Phys Med Rehabil. 1978; 59: 467-484
        • Tardieu C.
        • Tabary J.C.
        • Tabary C.
        • Tardieu G.
        Adaptation of connective tissue length to immobilization in the lengthened and shortened positions in the cat soleus muscle.
        J de Physiol. 1982; 78: 214-220
        • Garrett W.E.
        • Safran M.R.
        • Seaber A.V.
        • Glisson R.R.
        • Ribbck B.M.
        Biomechanical comparison of stimulated and nonstimulated skeletal muscle pulled to failure.
        Am J Sports Med. 1987; 15: 448-454
        • Garrett W.E.
        • Nilolaou P.K.
        • Ribbeck B.M.
        • Glisson R.R.
        • Seaber A.V.
        The effect of muscle architecture on the biomechanical failure properties of skeletal muscle under passive extension.
        Am J Sports Med. 1988; 16: 7-12
        • Gajdosik R.L.
        Flexibility or muscle length? [letter: commentary].
        Phys Ther. 1995; 75: 238-239
        • Gajdosik R.L.
        • Vander Linden D.W.
        • Williams A.K.
        Influence of age on length and passive elastic stiffness characteristics of the calf muscle–tendon unit of women.
        Phys Ther. 1999; 79: 827-838
        • Magnusson S.P.
        Passive properties of human skeletal muscle during stretch maneuvers: a review.
        Scand J Med Sci Sports. 1998; 8: 65-77
        • Gajdosik R.L.
        • Bohannon R.W.
        Clinical measurement of range of motion: review of goniometry emphasizing reliability and validity.
        Phys Ther. 1987; 67: 1867-1872
      2. LeVeau BF. Williams & Lissner’s biomechanics of human motion. 3rd ed. Philadelphia: W.B. Saunders; 1992. p. 33–37

        • Magnusson S.P.
        • Simonsen E.B.
        • Aagaard P.
        • Gleim G.W.
        • McHugh M.P.
        • Kjaer M.
        Viscoelastic response to repeated static stretching in human hamstring muscle.
        Scand J Med Sci Sports. 1995; 5: 342-347
        • Magnusson S.P.
        • Simonsen E.B.
        • Aagaard P.
        • Kjaer M.
        Biomechanical responses to repeated stretches in human hamstring muscle in vivo.
        Am J Sports Med. 1996; 24: 622-628
        • Magnusson S.P.
        • Simonsen E.B.
        • Aagaard P.
        • Boesen J.
        • Johannsen F.
        • Kjaer M.
        Determinants of musculoskeletal flexibility: viscoelastic properties, cross-sectional area, EMG and stretch tolerance.
        Scand J Med Sci Sports. 1997; 7: 195-202
        • Klinge K.
        • Magnusson S.P.
        • Simonsen E.B.
        • Aagaard P.
        • Klausen K.
        • Kjaer M.
        The effect of strength and flexibility training on skeletal muscle electromyographic activity, stiffness, and viscoelastic stress relaxation response.
        Am J Sports Med. 1997; 25: 710-716
        • Magnusson S.P.
        • Simonsen E.B.
        • Aagaard P.
        • Sorensen H.
        • Kjaer M.
        A mechanism for altered flexibility in human skeletal muscle.
        J Physiol. 1996; 4971: 291-298
        • Taylor D.C.
        • Dayton J.D.
        • Seaber A.V.
        • Garrett W.E.
        Viscoelastic properties of muscle–tendon units. The biomechanical effects of stretching.
        Am J Sports Med. 1990; 18: 300-308
        • Gajdosik R.L.
        Influence of age on calf muscle length and passive stiffness variables at different stretch velocities.
        Isokinetics Exerc Sci. 1997; 6: 163-174
        • McHugh M.P.
        • Kremenic I.J.
        • Fox M.B.
        • Gleim G.W.
        The role of mechanical and neural restraints to joint range of motion during passive stretch.
        Med Sci Sports Exerc. 1998; 30: 928-932
        • Magnusson S.P.
        • Aagaard P.
        • Simonsen E.
        • Bojsen-Moller F.
        A biomechanical evaluation of cyclic and static stretch in human skeletal muscle.
        Int J Sports Med. 1998; 19: 310-316
        • McHugh M.P.
        • Magnusson S.P.
        • Gleim G.W.
        • Nicholas J.A.
        Viscoelastic stress relaxation in human skeletal muscle.
        Med Sci Sports Exerc. 1992; 24: 1375-1382
        • Magnusson S.P.
        • Simonsen E.B.
        • Aagaard P.
        • Moritz U.
        Contraction specific changes in passive torque in human skeletal muscle.
        Acta Physiol Scand. 1995; 155: 377-386
        • Magnusson S.P.
        • Simonsen E.B.
        • Aagaard P.
        • Dyhre-Poulsen P.
        • McHugh M.P.
        • Kjaer M.
        Mechanical and physiological response to stretching with and without preisometric contraction in human skeletal muscle.
        Arch Phys Med Rehabil. 1996; 77: 373-378
        • Magnusson S.P.
        • Simonsen E.B.
        • Dyhre-Poulsen P.
        • Asgaard P.
        • Mohr T.
        • Kjaer M.
        Viscoelastic stress relaxation during static stretch in human skeletal muscle in the absence of EMG activity.
        Scand J Med Sci Sports. 1996; 6: 323-328
        • Hill D.K.
        Tension due to interaction between sliding filaments in resting striated muscle: the effect of stimulation.
        J Physiol. 1968; 199: 637-684
        • Hill D.K.
        The effect of temperature in the range of 0–35°C on the resting tension of frog’s muscle.
        J Physiol. 1970; 208: 725-739
        • Hill D.K.
        The effect of temperature on the resting tension of frog's muscle in hypertonic solutions.
        J Physiol. 1970; 208: 741-756
        • Proske U.
        • Morgan D.L.
        Do cross-bridges contribute to the tension during stretch of passive muscle?.
        J Muscle Res Cell Motil. 1999; 20: 433-442
        • Campbell K.S.
        • Lakie M.
        A cross-bridge mechanism can explain the thixotropic short-range elastic component of relaxed frog skeletal muscle.
        J Physiol. 1998; 510: 941-962
        • Gajdosik R.L.
        • Guiliani C.A.
        • Bohannon R.W.
        Passive compliance and length of the hamstring muscles of healthy men and women.
        Clin Biomech. 1990; 5: 23-29
        • Gajdosik R.L.
        Passive compliance and length of clinically short hamstring muscles of healthy men.
        Clin Biomech. 1991; 6: 239-244
        • Gajdosik R.L.
        Effects of static stretching on the maximal length and resistance to passive stretch of short hamstring muscles.
        J Orthop Sports Phys Ther. 1991; 14: 250-255
        • Gajdosik R.L.
        • Vander D.W.
        • Linden A.K.
        Influence of age on concentric isokinetic torque and passive extensibility variables of the calf muscles of women.
        Eur J Appl Physiol. 1996; 74: 279-286
        • Huxley H.E.
        • Stewart A.
        • Sosa H.
        • Irving T.
        X-ray diffraction measurements of the extensibility of actin and myosin filaments in contracting muscle.
        Biophys J. 1994; 67: 2411-2421
        • Wakabayashi K.
        • Sugimoto Y.
        • Tanaka H.
        • Ueno Y.
        • Takezawa Y.
        • Amemiya Y.
        X-ray diffraction evidence for the extensibility of actin and myosin filaments during muscle contraction.
        Biophys J. 1994; 67: 2422-2435
        • Goldman Y.E.
        • Huxley A.F.
        Actin compliance: Are you pulling my chain?.
        Biophys J. 1994; 67: 2131-2136
      3. Takezawa Y, Sugimoto Y, Wakabayashi K. Extensibility of actin and myosin filaments in various states of skeletal muscle as studied by X-ray diffraction. Adv Exp Biol 1998:309–16 [discussion 317]

        • Magid A.
        • Law D.J.
        Myofibrils bear most of the resting tension in frog skeletal muscle.
        Science. 1985; 230: 1280-1282
        • Granzier H.L.M.
        • Pollack G.H.
        Stepwise shortening in unstimulated frog skeletal muscle fibers.
        J Physiol. 1985; 362: 173-188
        • Waterman-Storer C.M.
        The cytoskeleton of skeletal muscle: Is it affected by exercise? A brief review.
        Med Sci Sports Exer. 1991; 23: 1240-1249
        • Wang K.
        • McCarter R.
        • Wright J.
        • Beverly J.
        • Ramirez-Mitchell R.
        Viscoelasticity of the sarcomere matrix of skeletal muscles: the titin-myosin composite filament is a dual-stage molecular spring.
        Biophys J. 1993; 64: 1161-1177
        • Funatsu T.
        • Higuchi H.
        • Ishiwata S.
        Elastic filaments in skeletal muscle revealed by selective removal of thin filaments with plasma gelsolin.
        J Cell Biol. 1996; 110: 53-62
        • Linke W.A.
        • Ivemeyer M.
        • Olivieri N.
        • Lolmerer B.
        • Ruegg J.C.
        • Labeit S.
        Towards a molecular understanding of the elasticity of titin.
        J Mol Biol. 1996; 261: 62-71
        • Trombitas K.
        • Greaser M.
        • Labeit S.
        • Jin J.-.P.
        • Kellermayer M.
        • Helmes M.
        • Granzier H.
        Titin extensibility in situ: entropic elasticity of permanently folded and permanently unfolded molecular segments.
        J Cell Biol. 1998; 140: 853-859
        • Mutungi G.
        • Ranatunga K.W.
        The viscous, viscoelastic and elastic characteristics of resting fast and slow mammalian (rat) muscle fibers.
        J Physiol (London). 1996; 496: 827-836
        • Tokuyasu K.T.
        • Dutton A.H.
        • Singer S.J.
        Immunoelectron microscopic studies of desmin (skeletin) localization and intermediate filament organization in chicken skeletal muscle.
        J Cell Biol. 1983; 96: 1727-1735
        • Wang K.
        • Ramirez-Mitchell R.
        A network of transverse and longitudinal intermediate filaments is associated with sarcomeres of adult vertebrate skeletal muscle.
        J Cell Biol. 1983; 96: 562-570
        • Weigner A.W.
        • Watts R.L.
        Elastic properties of muscles measured at the elbow in man: I Normal controls.
        J Neurol Neurolsurg Psychiatry. 1986; 49: 1171-1176
        • Gajdosik R.L.
        • Vander D.W.
        • Linden A.K.
        Concentric isokinetic torque characteristics of the calf muscles of active women aged 20–84 years.
        J Orthop Sports Phys Ther. 1999; 29: 181-190
        • Borg T.K.
        • Caulfield J.B.
        Morphology of connective tissue in skeletal muscle.
        Tissue Cell. 1980; 12: 197-207
        • Rowe R.W.D.
        Morphology of perimysial and endomysial connective tissue in skeletal muscle.
        Tissue Cell. 1981; 13: 681-690
        • Rowe R.W.D.
        Collagen fibre arrangement in intramuscular connective tissue. Changes associated with muscle shortening and their possible relevance to raw meat toughness measurements.
        J Food Technol. 1974; 9: 501-508
        • Purslow P.P.
        Strain-induced reorientation of an intramuscular connective tissue network: implications for passive muscle elasticity.
        J Biomech. 1989; 22: 221-312
        • Williams P.E.
        • Goldspink G.
        Connective tissue changes in immobilized muscle.
        J Anat (London). 1984; 138: 342-350
        • Alder A.B.
        • Crawford G.N.C.
        • Edwards G.R.
        The effect of limitation of movement on longitudinal muscle growth.
        Proc Roy Soc London. Series B: Biol Sci. 1959; 150: 554-562
        • Jarvinen M.J.
        • Einola S.A.
        • Virtanen E.O.
        Effect of the position of immobilization upon the tensile properties of the rat gastrocnemius muscle.
        Arch Phys Med Rehabil. 1992; 73: 253-257
        • Stolov W.C.
        • Riddell W.M.
        • Shrier K.P.
        Effect of electrical stimulation on contracture of immobilized, innervated and denervated muscle (Abstract).
        Arch Phys Med Rehabil. 1971; 52: 589
        • Goldspink G.
        • Tabary C.
        • Tabary J.C.
        • Tardieu C.
        • Tardieu G.
        Effect of denervation on the adaptation of sarcomere number and muscle extensibility to the functional length of the muscle.
        J Physiol. 1974; 236: 733-742
        • Williams P.E.
        • Goldspink G.
        The effect of immobilization on the longitudinal growth of striated muscle fibers.
        J Anat (London). 1973; 116: 45-55
        • Williams P.E.
        • Goldspink G.
        Longitudinal growth of striated muscle fibers.
        J Cell Sci. 1971; 9: 751-767
        • Herbert R.D.
        • Balnave R.J.
        The effect of position of immobilisation on resting length, resting stiffness, and weight of the soleus muscle of the rabbit.
        J Orthop Res. 1993; 11: 358-366
        • Cardenas D.D.
        • Stolov W.C.
        • Hardy R.
        Muscle fiber number in immobilization atrophy.
        Arch Phys Med Rehabil. 1977; 58: 423-426
        • Williams P.E.
        Effect of intermittent stretch on immobilised muscle.
        Ann Rheum Dis. 1988; 47: 1014-1016
        • Williams P.E.
        • Catanese T.
        • Lucey E.G.
        • Goldspink G.
        The importance of stretch and contractile activity in the prevention of connective tissue accumulation in muscle.
        J Anat. 1988; 158: 109-114
        • Goldspink D.F.
        The influence of immobilization and stretch on protein turnover of rat skeletal muscle.
        J Physiol. 1977; 64: 267-282
        • Thomson J.D.
        Mechanical characteristics of skeletal muscle undergoing atrophy of degeneration.
        Am J Phys Med. 1955; 34: 606-611
        • Stolov W.C.
        • Weilepp Jr, T.B.
        • Riddell W.M.
        Passive length–tension relationship and hydroxyproline content of chronically denervated skeletal muscle.
        Arch Phys Med Rehabil. 1970; 51: 517-525
        • Huet de la Tour E.
        • Tabary J.C.
        • Tabary C.
        • Tardieu C.
        The respective roles of muscle length and muscle tension in sarcomere number adaptation of guinea-pig soleus muscle.
        J de Physiol. 1979; 75: 589-592
        • Huet de la Tour E.
        • Tardieu C.
        • Tabary J.C.
        • Tardieu C.
        Decreased muscle extensibility and reduction of sarcomere number in soleus muscle following local injection of tetanus toxin.
        J Neurol Sci. 1979; 40: 123-131
        • Tabary J.C.
        • Tardieu C.
        • Tardieu G.
        • Tabary C.
        Experimental rapid sarcomere loss with concomitant hypoextensibility.
        Muscle Nerve. 1981; 4: 198-203
        • Ziv I.
        • Blackburn N.
        • Rang
        • Koreska M.
        Muscle growth in normal and spastic mice.
        Dev Med Child Neurol. 1984; 26: 94-99
        • Gajdosik R.L.
        Contribution of passive resistive torque to total peak concentric isokinetic torque of the calf muscle–tendon unit.
        Isokinetics Exer Sci. 1999; 7: 135-143
        • Halbertsma J.P.K.
        • Goeken L.N.H.
        Stretching exercises: effect on passive extensibility and stiffness in short hamstrings of healthy subjects.
        Arch Phys Med Rehabil. 1994; 75: 976-981
        • Tardieu C.
        • Huet de la Tour E.
        • Bret M.D.
        • Tardieu G.
        Muscle hypoextensibility in children with cerebral palsy: I. Clinical and experimental observations.
        Arch Phys Med Rehabil. 1982; 63: 97-102
        • Tardieu G.
        • Tardieu C.
        • Colbeau-Justin P.
        • Lespargot A.
        Muscle hypoextensibility in children with cerebral palsy: II. Therapeutic implications.
        Arch Phys Med Rehabil. 1982; 63: 103-107
        • Tanigawa M.C.
        Comparison of the hold-relax procedure and passive mobilization on increased muscle length.
        Phys Ther. 1972; 52: 725-735
        • Medeiros J.M.
        • Smidt G.L.
        • Burmeister L.F.
        • Soderberg G.L.
        The influence of isometric exercise and passive stretch on hip joint motion.
        Phys Ther. 1977; 57: 518-523
        • Moore M.A.
        • Hutton R.S.
        Electromyographic investigation of muscle stretching techniques.
        Med Sci Sports Exer. 1980; 12: 322-329
        • Halkovich L.R.
        • Personius W.J.
        • Clamann H.P.
        • Newton R.A.
        Effect of Flouri-Methane® spray on passive hip flexion.
        Phys Ther. 1981; 61: 185-189
        • Sady S.P.
        • Wortman M.
        • Blanke D.
        Flexibility training: ballistic, static or proprioceptive neuromuscular facilitation.
        Arch Phys Med Rehabil. 1982; 63: 261-263
        • Bohannon R.W.
        Effect of repeated eight-minute muscle loading on the angle of straight-leg raising.
        Phys Ther. 1984; 64: 491-497
        • Hubley C.L.
        • Kozey J.W.
        • Stanish W.D.
        The effects of static stretching exercises and stationary cycling on range of motion at the hip joint.
        J Orthop Sports Phys Ther. 1984; 6: 104-109
        • Gajdosik R.L.
        • Le Veau B.F.
        • Bohannon R.W.
        Effects of ankle dorsiflexion on active and passive unilateral straight leg raising.
        Phys Ther. 1985; 65: 1478-1482
        • Wallin D.
        • Ekblom B.
        • Grahn R.
        • Nordenborg T.
        Improvement of muscle flexibility: a comparison between two techniques.
        Am J Sports Med. 1985; 13: 263-268
        • Williford H.N.
        • East J.B.
        • Smith F.H.
        • Burry L.A.
        Valuation of warm-up for improvement in flexibility.
        Am J Sports Med. 1986; 14: 316-319
        • Borms J.
        • Van P.
        • Roy J.-P.
        • Santens A.
        Optimal duration of static stretching exercises for improvement of coxo-femoral flexibility.
        J Sports Sci. 1987; 5: 39-47
        • Godges J.J.
        • MacRae H.
        • Longdon C.
        • Tinberg C.
        • MacRae P.
        The effects of two stretching procedures on hip range of motion and gait economy.
        J Orthop Sports Phys Ther. 1989; 10: 350-357
        • Gajdosik R.L.
        • Rieck M.A.
        • Sullivan D.K.
        • Wightman S.E.
        Comparison and relationship of four clinical tests for hamstring muscle length.
        J Orthop Sports Phys Ther. 1993; 18: 614-618
        • Gajdosik R.
        • Lusin G.
        Hamstring muscle tightness: reliability of an active-knee-extension test.
        Phys Ther. 1983; 4: 154-157
        • Osternig L.R.
        • Robertson R.
        • Troxel R.
        • Hansen P.
        Muscle activation during proprioceptive neuromuscular facilitation (PNF) stretching techniques.
        Am J Phys Med. 1987; 66: 298-307
        • Osternig L.R.
        • Robertson R.
        • Troxel R.
        • Hansen P.
        Differential responses to proprioceptive neuromuscular facilitation (PNF) stretch techniques.
        Med Sci Sports Exer. 1990; 22: 106-111
        • Bandy W.D.
        • Irion J.M.
        • Briggler M.
        The effect of time and frequency of static stretching on flexibility of the hamstring muscles.
        Phys Ther. 1997; 77: 1090-1096
        • Bohannon R.W.
        Cinematographic analysis of the passive straight-leg-raising test for hamstring muscle length.
        Phys Ther. 1982; 62: 1269-1274
        • Bohannon R.
        • Gajdosik R.
        • LeVeau B.F.
        Contribution of pelvic and lower limb motion to increases in the angle of passive straight leg raising.
        Phys Ther. 1984; 65: 474-476
        • Brown A.
        • Salmond S.
        • Maxwell L.
        Assessment of hamstring flexibility. Which Test?.
        N Z J Physiother. 1993; 21: 33-34
        • Gajdosik R.L.
        • Albert C.
        • Mitman J.
        Influence of hamstring length on the standing position and range of motion of the pelvic angle, lumbar angle, and thoracic angle.
        J Orthop Sports Phys Ther. 1994; 20: 213-219
        • Tardieu C.
        • Tardieu G.
        • Colbeau-Justin P.
        • Huet E.
        Trophic muscle regulation in children with congenital cerebral lesions.
        J Neurol Sci. 1979; 42: 357-364
        • McPherson J.J.
        • Arends T.G.
        • Michaels M.J.
        • Trettin K.
        The range of motion of long term knee contractures of four spastic cerebral palsied children: a pilot study.
        Physi Occup Ther Pediatr. 1984; 4: 17-34
        • Bohannon R.W.
        • Larkin P.A.
        Passive ankle dorsiflexion increases in patients after a regimen of tilt table-wedge board standing.
        Phys Ther. 1985; 65: 1676-1678
        • Reimers J.
        Functional changes in the antagonists after lengthening the agonists in cerebral palsy: I. Triceps surae lengthening.
        Clin Orthop. 1990; 253: 30-34
        • Reimers J.
        Functional changes in the antagonists after lengthening the agonists in cerebral palsy: II. Quadriceps strength before and after distal hamstring lengthening.
        Clin Orthop. 1990; 253: 35-37
        • Mills V.M.
        Electromyographic results of inhibitory splinting.
        Phys Ther. 1984; 64: 190-193
        • Brouwer B.
        • Wheeldon R.K.
        • Stradiotto-Parker N.
        Reflex excitability and isometric force production in cerebral palsy: the effect of serial casting.
        Develop Med Child Neurol. 1998; 40: 168-175
        • Cunningham D.A.
        • Morrison D.
        • Rice C.L.
        • Cooke C.
        Ageing and isokinetic plantar flexion.
        Eur J Appl Physiol. 1987; 56: 24-29
        • Fugl-Meyer A.R.
        • Gustafsson L.
        • Burstedt Y.
        Isokinetic and static plantar flexion characteristics.
        Eur J Appl Physiol. 1980; 45: 221-234
        • Vandervoort A.A.
        • Hayes K.C.
        Plantarflexion muscle function in young and elderly women.
        Eur J Appl Physiol. 1989; 58: 389-394
        • Vandervoort A.A.
        • McComas A.J.
        Contractile changes in opposing muscles of the human ankle joint with aging.
        J Appl Physiol. 1986; 61: 361-367
        • Campbell M.J.
        • McComas A.J.
        • Petito F.
        Physiological changes in ageing muscles.
        J Neurol, Neurosurg Psychiatry. 1973; 36: 174-182
        • Doherty T.J.
        • Brown W.F.
        The estimated numbers and relative sizes of thenar motor units as selected by multiple point stimulation in young and older adults.
        Muscle Nerve. 1993; 16: 355-366
        • Doherty T.J.
        • Vandervoort A.A.
        • Taylor A.W.
        • Brown W.F.
        Effects of motor unit losses on strength in older men and women.
        J Appl Physiol. 1993; 74: 868-874
        • Lexell J.
        Human aging, muscle mass, and fiber type composition.
        J Gerontol A. 1995; 50: 11-16
        • Lexell J.
        • Hendriksson-Larsen K.
        • Winblad B.
        • Sjostrom M.
        Distribution of different fiber types in human skeletal muscle: effects of aging studied in whole muscle cross sections.
        Muscle Nerve. 1983; 6: 588-595
        • Lexell J.
        • Taylor C.C.
        • Sjostrom M.
        What is the cause of ageing atrophy? Total number, size and proportion of different fiber types studied in whole vastus lateralis muscle from 15 to 83 yr old men.
        J Neurol Sci. 1988; 84: 275-294
        • Essen-Gustavsson B.
        • Borges O.
        Histochemical and metabolic characteristics of human skeletal muscle in relation to age.
        Acta Physiol Scand. 1986; 126: 107-114
        • Grimby G.
        • Danneskiold-Samsoe B.
        • Hvid K.
        • Saltin B.
        Morphology and enzymatic capacity in arm and leg muscles in 78–81 yr old men and women.
        Acta Physil Scand. 1982; 115: 125-134
        • James B.
        • Parker A.W.
        Active and passive mobility of lower limb joints in elderly men and women.
        Am J Phys Med Rehabil. 1989; 68: 162-167
        • Vandervoort A.A.
        • Chesworth B.M.
        • Cunningham D.A.
        • Paterson D.H.
        • Rechnitzer P.A.
        • Koval J.J.
        Age and sex effects on mobility of the human ankle.
        J Gerontol. 1992; 47: M17-M21
        • Chesworth B.M.
        • Vandervoort A.A.
        Age and passive ankle stiffness in healthy women.
        Phys Ther. 1989; 69: 217-224
        • Overend T.J.
        • Cunningham D.A.
        • Paterson D.H.
        • Lefcoe M.S.
        Thigh composition in young and elderly men determined by computed tomography.
        Clin Physiol. 1992; 12: 629-640
        • Rice C.L.
        • cunningham D.A.
        • Paterson D.H.
        • Lefcoe M.S.
        Arm and leg composition determined by computed tomography in young and elderly men.
        Clin Physiol. 1989; 9: 207-220
        • Sipila S.
        • Suominen H.
        Effects of strength and endurance training on thigh and leg muscle mass and composition in elderly women.
        J Appl Physiol. 1995; 78: 334-340
        • Gosselin L.E.
        • Adams C.
        • Cotter T.A.
        • McCormick R.J.
        • Thomas D.P.
        Effects of exercise training on passive stiffness in locomotor skeletal muscle: role of extracellular matrix.
        J Appl Physiol. 1989; 85: 1011-1016