Sports Medicine

, Volume 34, Issue 4, pp 253–267 | Cite as

Assessing Voluntary Muscle Activation with the Twitch Interpolation Technique

  • Anthony ShieldEmail author
  • Shi Zhou
Review Article


The twitch interpolation technique is commonly employed to assess the completeness of skeletal muscle activation during voluntary contractions. Early applications of twitch interpolation suggested that healthy human subjects could fully activate most of the skeletal muscles to which the technique had been applied. More recently, however, highly sensitive twitch interpolation has revealed that even healthy adults routinely fail to fully activate a number of skeletal muscles despite apparently maximal effort. Unfortunately, some disagreement exists as to how the results of twitch interpolation should be employed to quantify voluntary activation. The negative linear relationship between evoked twitch force and voluntary force that has been observed by some researchers implies that voluntary activation can be quantified by scaling a single interpolated twitch to a control twitch evoked in relaxed muscle.

Observations of non-linear evoked-voluntary force relationships have lead to the suggestion that the single interpolated twitch ratio can not accurately estimate voluntary activation. Instead, it has been proposed that muscle activation is better determined by extrapolating the relationship between evoked and voluntary force to provide an estimate of true maximum force. However, criticism of the single interpolated twitch ratio typically fails to take into account the reasons for the non-linearity of the evoked-voluntary force relationship. When these reasons are examined, it appears that most are even more challenging to the validity of extrapolation than they are to the linear equation. Furthermore, several factors that contribute to the observed non-linearity can be minimised or even eliminated with appropriate experimental technique. The detection of small activation deficits requires high resolution measurement of force and careful consideration of numerous experimental details such as the site of stimulation, stimulation intensity and the number of interpolated stimuli. Sensitive twitch interpolation techniques have revealed small to moderate deficits in voluntary activation during brief maximal efforts and progressively increasing activation deficits (central fatigue) during exhausting exercise. A small number of recent studies suggest that resistance training may result in improved voluntary activation of the quadriceps femoris and ankle plantarflexor muscles but not the biceps brachii. A significantly larger body of evidence indicates that voluntary activation declines as a consequence of bed-rest, joint injury and joint degeneration. Twitch interpolation has also been employed to study the mechanisms by which caffeine and pseudoephedrine enhance exercise performance.


Resistance Training Voluntary Activation Biceps Brachii Elbow Flexor Adductor Pollicis 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported by the Internal Research Grants of Southern Cross University. The authors have no conflicts of interest that are directly relevant to the content of this review.


  1. 1.
    Belanger AY, McComas AJ. Extent of motor unit activation during effort. J Appl Physiol 1981; 51(5): 1131–5PubMedGoogle Scholar
  2. 2.
    Denny-Brown D. On inhibition as a reflex accompaniment of the tendon jerk and of other forms of active muscular response. Proc R Soc Lond B Biol Sci 1928; 103: 321–36Google Scholar
  3. 3.
    Merton PA. Voluntary strength and muscle fatigue. J Physiol 1954; 123: 553–64PubMedGoogle Scholar
  4. 4.
    Belanger AY, McComas AJ. Contractile properties of human skeletal muscle in childhood and adolescence. Eur J Appl Physiol Occup Physiol 1989; 58(6): 563–7PubMedGoogle Scholar
  5. 5.
    Bigland-Ritchie B, Furbush F, Woods JJ. Fatigue of intermittent submaximal voluntary contractions: central and peripheral factors. J Appl Physiol 1986; 61(2): 421–9PubMedGoogle Scholar
  6. 6.
    Chapman SJ, Edwards RHT, Greig C, et al. Practical application of the twitch interpolation technique for the study of voluntary contraction of the quadriceps muscle in man [abstract]. J Physiol 1984; 353: 3PGoogle Scholar
  7. 7.
    Davies J, Parker DF, Rutherford OM, et al. Changes in strength and cross sectional area of the elbow flexors as a result of isometric strength training. Eur J Appl Physiol Occup Physiol 1988; 57: 667–70PubMedGoogle Scholar
  8. 8.
    Garfinkel S, Cafarelli E. Relative changes in maximal force, EMG, and muscle cross-sectional area after isometric training. Med Sci Sports Exerc 1992; 24(11): 1220–7PubMedGoogle Scholar
  9. 9.
    Rutherford OM, Jones DA, Newham DJ. Clinical and experimental application of the percutaneous twitch superimposition technique for the study of human muscle activation. J Neurol Neurosurg Psychiatry 1986; 49: 1288–91PubMedGoogle Scholar
  10. 10.
    Rutherford OM, Greg CA, Sargeant AJ, et al. Strength training and power output: transference effects in the human quadriceps muscle. J Sports Sci 1986; 4: 101–7PubMedGoogle Scholar
  11. 11.
    Rutherford OM, Jones DA. The role of learning and coordination in strength training. Eur J Appl Physiol Occup Physiol 1986; 55(1): 100–5PubMedGoogle Scholar
  12. 12.
    Vandervoort AA, McComas AJ. Contractile changes in opposing muscles of the human ankle joint with aging. J Appl Physiol 1986; 61(1): 361–7PubMedGoogle Scholar
  13. 13.
    Hales JP, Gandevia SC. Assessment of maximal voluntary contraction with twitch interpolation: an instrument to measure twitch responses. J Neurosci Methods 1988; 25(2): 97–102PubMedGoogle Scholar
  14. 14.
    Dowling JJ, Konert E, Ljucovic P, et al. Are humans able to voluntarily elicit maximum muscle force? Neurosci Lett 1994; 179(1–2): 25–8PubMedGoogle Scholar
  15. 15.
    Allen GM, Gandevia SC, McKenzie DK. Reliability of measurements of muscle strength and voluntary activation using twitch interpolation. Muscle Nerve 1995; 18(6): 593–600PubMedGoogle Scholar
  16. 16.
    Allen GM, McKenzie DK, Gandevia SC. Twitch interpolation of the elbow flexor muscles at high forces. Muscle Nerve 1998; 21(3): 318–28PubMedGoogle Scholar
  17. 17.
    Babault N, Pousson M, Michaut A, et al. EMG activity and voluntary activation during knee-extensor concentric torque generation. Eur J Appl Physiol 2002; 86(6): 541–7PubMedGoogle Scholar
  18. 18.
    Behm D, Whittle J, Button D, et al. Intermuscle differences in activation. Muscle Nerve 2002; 25(2): 236–43PubMedGoogle Scholar
  19. 19.
    Gandevia SC, Allen GM, Butler JE, et al. Supraspinal factors in human muscle fatigue: evidence for suboptimal output from the motor cortex. J Physiol 1996; 490 (Pt 2): 529–36PubMedGoogle Scholar
  20. 20.
    Herbert RD, Gandevia SC. Muscle activation in unilateral and bilateral efforts assessed by motor nerve and cortical stimulation. J Appl Physiol 1996; 80(4): 1351–6PubMedGoogle Scholar
  21. 21.
    Jakobi JM, Cafarelli E. Neuromuscular drive and force production are not altered during bilateral contractions. J Appl Physiol 1998; 84(1): 200–6PubMedGoogle Scholar
  22. 22.
    McKenzie DK, Bigland-Ritchie B, Gorman RB, et al. Central and peripheral fatigue of human diaphragm and limb muscles assessed by twitch interpolation. J Physiol 1992; 454: 643–56PubMedGoogle Scholar
  23. 23.
    Roos MR, Rice CL, Connelly DM, et al. Quadriceps muscle strength, contractile properties, and motor unit firing rates in young and old men. Muscle Nerve 1999; 22(8): 1094–103PubMedGoogle Scholar
  24. 24.
    Gandevia SC. Spinal and supraspinal factors in human muscle fatigue. Physiol Rev 2001; 81: 1725–89PubMedGoogle Scholar
  25. 25.
    Gandevia SC, McKenzie DK. Activation of human muscles at short muscle lengths during maximal static efforts. J Physiol 1988; 407: 599–613PubMedGoogle Scholar
  26. 26.
    Lyons MF, Cadden SW, Baxendale RH, et al. Twitch interpolation in the assessment of the maximum force-generating capacity of the jaw-closing muscles in man. Arch Oral Biol 1996; 41(12): 1161–8PubMedGoogle Scholar
  27. 27.
    Behm D, Power K, Drinkwater E. Comparison of interpolation and central activation ratios as measures of muscle inactivation. Muscle Nerve 2001; 24(7): 925–34PubMedGoogle Scholar
  28. 28.
    Behm DG, St-Pierre DM, Perez D. Muscle inactivation: assessment of interpolated twitch technique. J Appl Physiol 1996; 81(5): 2267–73PubMedGoogle Scholar
  29. 29.
    Suter E, Herzog W, Huber A. Extent of motor unit activation in the quadriceps muscles of healthy subjects. Muscle Nerve 1996; 19: 1046–8PubMedGoogle Scholar
  30. 30.
    Bulow PM, Norregaard J, Danneskiold-Samsøe B, et al. Twitch interpolation technique in testing of maximal muscle strength: influence of potentiation, force level, stimulus intensity and preload. Eur J Appl Physiol Occup Physiol 1993; 67(5): 462–6PubMedGoogle Scholar
  31. 31.
    Scaglioni G, Ferri A, Minetti AE, et al. Plantar flexor activation capacity and H reflex in older adults: adaptations to strength training. J Appl Physiol 2002; 92(6): 2292–302PubMedGoogle Scholar
  32. 32.
    De Serres SJ, Enoka RM. Older adults can maximally activate the biceps brachii muscle by voluntary command. J Appl Physiol 1998; 84(1): 284–91PubMedGoogle Scholar
  33. 33.
    Herbert RD, Gandevia SC. Twitch interpolation in human muscles: mechanisms and implications for measurement of voluntary activation. J Neurophysiol 1999; 82(5): 2271–83PubMedGoogle Scholar
  34. 34.
    Kawakami Y, Amemiya K, Kanehisa H, et al. Fatigue responses of human triceps surae muscles during repetitive maximal isometric contractions. J Appl Physiol 2000; 88(6): 1969–75PubMedGoogle Scholar
  35. 35.
    Loscher WN, Cresswell AG, Thorstensson A. Central fatigue during a long-lasting submaximal contraction of the triceps surae. Exp Brain Res 1996; 108(2): 305–14PubMedGoogle Scholar
  36. 36.
    James C, Sacco P, Hurley MV, et al. An evaluation of different protocols for measuring the force-velocity relationship of the human quadriceps muscle. Eur J Appl Physiol Occup Physiol 1994; 68: 41–7PubMedGoogle Scholar
  37. 37.
    Loring SH, Hershenson MB. Effects of series compliance on twitches superimposed on voluntary contractions. J Appl Physiol 1992; 73(2): 516–21PubMedGoogle Scholar
  38. 38.
    Kawakami Y, Akima H, Kubo K, et al. Changes in muscle size, architecture, and neural activation after 20 days of bed rest with and without resistance exercise. Eur J Appl Physiol 2001; 84(1–2): 7–12PubMedGoogle Scholar
  39. 39.
    Hurley MV, Jones DW, Newham DJ. Arthrogenic quadriceps inhibition and rehabilitation of patients with extensive traumatic knee injuries [published erratum appears in Clin Sci 1994 Jun; 86 (6): xxii.]. Clin Sci 1994; 86(3): 305–10PubMedGoogle Scholar
  40. 40.
    Norregaard J, Bülow PM, Danneskiold-Samsøe B. Muscle strength, voluntary activation, twitch properties, and endurance in patients with fibromyalgia. J Neurol Neurosurg Psychiatry 1994; 57(9): 1106–11PubMedGoogle Scholar
  41. 41.
    Norregaard J, Bülow PM, Vestergaard-Poulsen P, et al. Muscle strength, voluntary activation and cross-sectional muscle area in patients with fibromyalgia. Br J Rheumatol 1995; 34(10): 925–31PubMedGoogle Scholar
  42. 42.
    Maffiuletti NA, Pensini M, Martin A. Activation of human plantar flexor muscles increases after electromyostimulation training. J Appl Physiol 2002; 92(4): 1383–92PubMedGoogle Scholar
  43. 43.
    Miller M, Downham D, Lexell J. Superimposed single impulse and pulse train electrical stimulation: a quantitative assessment during submaximal isometric knee extension in young, healthy men. Muscle Nerve 1999; 22(8): 1038–46PubMedGoogle Scholar
  44. 44.
    Burke RE, Rudomin P, Zajac FE. Catch property in single mammalian motor units. Science 1970; 168(927): 122–4PubMedGoogle Scholar
  45. 45.
    Suter E, Herzog W. Effect of number of stimuli and timing of twitch application on variability in interpolated twitch torque. J Appl Physiol 2001; 90(3): 1036–40PubMedGoogle Scholar
  46. 46.
    Kukulka CG, Clamann HP. Comparison of the recruitment and discharge properties of motor units in human brachial biceps and adductor pollicis during isometric contractions. Brain Res 1981; 219(1): 45–55PubMedGoogle Scholar
  47. 47.
    Hultman E, Sjöholm H, Jäderholm-Ek I, et al. Evaluation of methods for electrical stimulation of human skeletal muscle in situ. Pflugers Arch 1983; 398(2): 139–41PubMedGoogle Scholar
  48. 48.
    Connelly DM, Rice CL, Roos MR, et al. Motor unit firing rates and contractile properties in tibialis anterior of young and old men. J Appl Physiol 1999; 7(2): 843–52Google Scholar
  49. 49.
    Awiszus F, Wahl B, Meinecke I. Influence of stimulus cross talk on results of the twitch-interpolation technique at the biceps brachii muscle. Muscle Nerve 1997; 20: 1187–90PubMedGoogle Scholar
  50. 50.
    Burke D, Gandevia SC. Influence of stimulus cross talk on results of the twitch-interpolation technique at the biceps brachii muscle. [letter]. Muscle Nerve 1998; 21(7): 970–1PubMedGoogle Scholar
  51. 51.
    Yue GH, Ranganathan VK, Siemionow V, et al. Evidence of inability to fully activate human limb muscle. Muscle Nerve 2000; 23(3): 376–84PubMedGoogle Scholar
  52. 52.
    Vagg R, Mogyoros I, Kiernan MC, et al. Activity-dependent hyperpolarization of human motor axons produced by natural activity. J Physiol 1998; 507 (Pt 3): 919–25PubMedGoogle Scholar
  53. 53.
    Galganski ME, Fuglevand AJ, Enoka RM. Reduced control of motor output in a human hand muscle of elderly subjects during submaximal contractions. J Neurophysiol 1993; 69(6): 2108–15PubMedGoogle Scholar
  54. 54.
    Gandevia SC, McKenzie DK. Activation of the human diaphragm during maximal static efforts. J Physiol 1985; 367: 45–56PubMedGoogle Scholar
  55. 55.
    Kent-Braun JA, Le Blanc R. Quantitation of central activation failure during maximal voluntary contractions in humans. Muscle Nerve 1996; 19(7): 861–9PubMedGoogle Scholar
  56. 56.
    Newham DJ, McCarthy T, Turner J. Voluntary activation of human quadriceps during and after isokinetic exercise. J Appl Physiol 1991; 71(6): 2122–6PubMedGoogle Scholar
  57. 57.
    Stackhouse SK, Dean JC, Lee SC, et al. Measurement of central activation failure of the quadriceps femoris in healthy adults. Muscle Nerve 2000; 23: 1706–12PubMedGoogle Scholar
  58. 58.
    Strojnik V. Muscle activation level during maximal voluntary effort. Eur J Appl Physiol Occup Physiol 1995; 72(1–2): 144–9PubMedGoogle Scholar
  59. 59.
    Westing SH, Seger JY, Thorstensson A, et al. Effects of electrical stimulation on eccentric and concentric torque-velocity relationships during knee extension in man. Acta Physiol Scand 1990; 140(1): 17–22PubMedGoogle Scholar
  60. 60.
    Herbert RD, Gandevia SC, Allen GM. Sensitivity of twitch interpolation [letter]. Muscle Nerve 1997; 20(4): S21–3Google Scholar
  61. 61.
    Newham DJ, Hsiao SF. Detection and estimation of voluntary activation with percutaneous electrical stimulation of the human quadriceps at 1 and 100 Hz [abstract]. J Physiol 1996; 491: 71PGoogle Scholar
  62. 62.
    Binder-MacLeod SA, Halden EE, Jungles KA. Effects of stimulation intensity on the physiological responses of human motor units. Med Sci Sports Exerc 1995; 27(4): 536–65Google Scholar
  63. 63.
    Andreacci JL, LeMura LM, Cohen SL, et al. The effects of frequency of encouragement on performance during maximal exercise testing. J Sports Sci 2002; 20(4): 345–52PubMedGoogle Scholar
  64. 64.
    McNair PJ, Depledge J, Brettkelly M, et al. Verbal encouragement: effects on maximum effort voluntary muscle action. Br J Sports Med 1996; 30(3): 243–5PubMedGoogle Scholar
  65. 65.
    Moffatt RJ, Chitwood LF, Biggerstaff KD. The influence of verbal encouragement during assessment of maximal oxygen uptake. J Sports Med Phys Fitness 1994; 34(1): 45–9PubMedGoogle Scholar
  66. 66.
    Herbert RD, Dean C, Gandevia SC. Effects of real and imagined training on voluntary muscle activation during maximal isometric contractions. Acta Physiol Scand 1998; 163(4): 361–8PubMedGoogle Scholar
  67. 67.
    Sheean GL, Murray NM, Rothwell JC, et al. An electrophysiological study of the mechanism of fatigue in multiple sclerosis. Brain 1997; 120 (Pt 2): 299–315PubMedGoogle Scholar
  68. 68.
    Shima N, Ishida K, Katayama K, et al. Cross education of muscular strength during unilateral resistance training and detraining. Eur J Appl Physiol 2002; 86(4): 287–94PubMedGoogle Scholar
  69. 69.
    Blimkie CJR, Sale DG, Bar-Or O. Voluntary strength, evoked twitch contractile properties and motor unit activation of knee extensors in obese and non-obese adolescent males. Eur J Appl Physiol 1990; 61: 313–8Google Scholar
  70. 70.
    Bulow PM, Norregaard J, Mehlsen J, et al. The twitch interpolation technique for study of fatigue of human quadriceps muscle. J Neurosci Methods 1995; 62(1–2): 103–9PubMedGoogle Scholar
  71. 71.
    Harridge SD, Kryger A, Stensgaard A. Knee extensor strength, activation, and size in very elderly people following strength training. Muscle Nerve 1999; 22(7): 831–9PubMedGoogle Scholar
  72. 72.
    Huber A, Suter E, Herzog W. Inhibition of the quadriceps muscles in elite male volleyball players. J Sports Sci 1998; 16(3): 281–9PubMedGoogle Scholar
  73. 73.
    Kalmar JM, Cafarelli E. Effects of caffeine on neuromuscular function. J Appl Physiol 1999; 87(2): 801–8PubMedGoogle Scholar
  74. 74.
    Ramsay JA, Blimkie CJ, Smith K, et al. Strength training effects in prepubescent boys. Med Sci Sports Exerc 1990; 22(5): 605–14PubMedGoogle Scholar
  75. 75.
    Suter E, Herzog W. Extent of muscle inhibition as a function of knee angle. J Electromyogr Kinesiol 1997; 7(2): 123–30PubMedGoogle Scholar
  76. 76.
    Babault N, Pousson M, Ballay Y, et al. Activation of human quadriceps femoris during isometric, concentric, and eccentric contractions. J Appl Physiol 2001; 91(6): 2628–34PubMedGoogle Scholar
  77. 77.
    Gandevia SC, Herbert RD, Leeper JB. Voluntary activation of human elbow flexor muscles during maximal concentric contractions. J Physiol 1998; 512(2): 595–602PubMedGoogle Scholar
  78. 78.
    Häkkinen K, Komi PV. Training-induced changes in neuromuscular performance under voluntary and reflex conditions. Eur J Appl Physiol Occup Physiol 1986; 55(2): 147–55PubMedGoogle Scholar
  79. 79.
    Higbie EJ, Cureton KJ, Warren GL, et al. Effects of concentric and eccentric training on muscle strength, cross-sectional area, and neural activation. J Appl Physiol 1996; 81(5): 2173–81PubMedGoogle Scholar
  80. 80.
    Komi PV, Viitasalo JT, Rauramaa R, et al. Effect of isometric strength training of mechanical, electrical, and metabolic aspects of muscle function. Eur J Appl Physiol Occup Physiol 1978; 40(1): 45–55PubMedGoogle Scholar
  81. 81.
    Moritani T, deVries HA. Neural factors versus hypertrophy in the time course of muscle strength gain. Am J Phys Med 1979; 58(3): 115–30PubMedGoogle Scholar
  82. 82.
    Narici MV, Roi GS, Landoni L, et al. Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps. Eur J Appl Physiol Occup Physiol 1989; 59(4): 310–9PubMedGoogle Scholar
  83. 83.
    Ozmun JC, Mikesky AE, Surburg PR. Neuromuscular adaptations following prepubescent strength training. Med Sci Sports Exerc 1994; 26(4): 510–4PubMedGoogle Scholar
  84. 84.
    Grimby L, Hannerz J, Hedman B. The fatigue and voluntary discharge properties of single motor units in man. J Physiol 1981; 316: 545–54PubMedGoogle Scholar
  85. 85.
    Kamen G, Knight CA, Laroche DP, et al. Resistance training increases vastus lateralis motor unit firing rates in young and old adults [abstract]. Med Sci Sports Exerc 1998; 30: S337Google Scholar
  86. 86.
    Cannon B, Cafarelli E. Neuromuscular adaptations to training. J Appl Physiol 1987; 63(6): 2396–402PubMedGoogle Scholar
  87. 87.
    Hortobágyi T, Lambert NJ, Hill JP. Greater cross education following training with muscle lengthening than shortening. Med Sci Sports Exerc 1997; 29(1): 107–12PubMedGoogle Scholar
  88. 88.
    Housh TJ, Housh DJ, Weir JP, et al. Effects of unilateral concentric-only dynamic constant external resistance training. Int J Sports Med 1996; 17(5): 338–43PubMedGoogle Scholar
  89. 89.
    Ploutz LL, Tesch PA, Biro RL, et al. Effect of resistance training on muscle use during exercise. J Appl Physiol 1994; 76(4): 1675–81PubMedGoogle Scholar
  90. 90.
    Zhou S. Chronic neural adaptations to unilateral exercise: mechanisms of cross education. Exerc Sport Sci Rev 2000; 28(4): 177–84PubMedGoogle Scholar
  91. 91.
    Aagaard P, Simonsen EB, Andersen JL, et al. Neural adaptation to resistance training: changes in evoked V-wave and H-reflex responses. J Appl Physiol 2002; 92(6): 2309–18PubMedGoogle Scholar
  92. 92.
    Milner-Brown HS, Stein RB, Lee RG. Synchronization of human motor units: possible roles of exercise and supraspinal reflexes. Electroencephalogr Clin Neurophysiol 1975; 38(3): 245–54PubMedGoogle Scholar
  93. 93.
    Sale DG, MacDougall JD, Upton AR, et al. Effect of strength training upon motoneuron excitability in man. Med Sci Sports Exerc 1983; 15(1): 57–62PubMedGoogle Scholar
  94. 94.
    Brown AB, McCartney N, Sale DG. Positive adaptations to weight-lifting training in the elderly. J Appl Physiol 1990; 69(5): 1725–33PubMedGoogle Scholar
  95. 95.
    Carolan B, Cafarelli E. Adaptations in coactivation after isometric resistance training. J Appl Physiol 1992; 73(3): 911–7PubMedGoogle Scholar
  96. 96.
    Jones DA, Rutherford OM. Human muscle strength training: the effects of three different regimes and the nature of the resultant changes. J Physiol 1987; 391: 1–11PubMedGoogle Scholar
  97. 97.
    Sale DG, Martin JE, Moroz DE. Hypertrophy without increased isometric strength after weight training. Eur J Appl Physiol Occup Physiol 1992; 64(1): 51–5PubMedGoogle Scholar
  98. 98.
    Knight CA, Kamen G. Adaptations in muscular activation of the knee extensor muscles with strength training in young and older adults. J Electromyogr Kinesiol 2001; 11(6): 405–12PubMedGoogle Scholar
  99. 99.
    Coyle EF, Feiring DC, Rotkis TC, et al. Specificity of power improvements through slow and fast isokinetic training. J Appl Physiol 1981; 51(6): 1437–42PubMedGoogle Scholar
  100. 100.
    Kitai TA, Sale DG. Specificity of joint angle in isometric training. Eur J Appl Physiol Occup Physiol 1989; 58(7): 744–8PubMedGoogle Scholar
  101. 101.
    Lindh M. Increase of muscle strength from isometric quadriceps exercises at different knee angles. Scand J Rehabil Med 1979; 11(1): 33–6PubMedGoogle Scholar
  102. 102.
    Pousson M, Amiridis IG, Cometti G, et al. Velocity-specific training in elbow flexors. Eur J Appl Physiol Occup Physiol 1999; 80(4): 367–72PubMedGoogle Scholar
  103. 103.
    Wilson GJ, Murphy AJ, Walshe A. The specificity of strength training: the effect of posture. Eur J Appl Physiol Occup Physiol 1996; 73(3–4): 346–52PubMedGoogle Scholar
  104. 104.
    Murphy AJ, Wilson GJ. Poor correlations between isometric tests and dynamic performance: relationship to muscle activation. Eur J Appl Physiol Occup Physiol 1996; 73(3–4): 353–7PubMedGoogle Scholar
  105. 105.
    Behm DG, St-Pierre DM. Fatigue characteristics following ankle fractures. Med Sci Sports Exerc 1997; 29(9): 1115–23PubMedGoogle Scholar
  106. 106.
    Urbach D, Awiszus F. Impaired ability of voluntary quadriceps activation bilaterally interferes with function testing after knee injuries: a twitch interpolation study. Int J Sports Med 2002; 23(4): 231–6PubMedGoogle Scholar
  107. 107.
    Urbach D, Nebelung W, Weiler HT, et al. Bilateral deficit of voluntary quadriceps muscle activation after unilateral ACL tear. Med Sci Sports Exerc 1999; 31(12): 1691–6PubMedGoogle Scholar
  108. 108.
    Hurley MV, Newham DJ. The influence of arthrogenous muscle inhibition on quadriceps rehabilitation of patients with early, unilateral osteoarthritic knees. Br J Rheumatol 1993; 32(2): 127–31PubMedGoogle Scholar
  109. 109.
    Hurley MV, Scott DL, Rees J, et al. Sensorimotor changes and functional performance in patients with knee osteoarthritis. Ann Rheum Dis 1997; 56(11): 641–8PubMedGoogle Scholar
  110. 110.
    Urbach D, Nebelung W, Becker R, et al. Effects of reconstruction of the anterior cruciate ligament on voluntary activation of quadriceps femoris a prospective twitch interpolation study. J Bone Joint Surg Br 2001; 83(8): 1104–10PubMedGoogle Scholar
  111. 111.
    Machner A, Pap G, Awiszus F. Evaluation of quadriceps strength and voluntary activation after unicompartmental arthroplasty for medial osteoarthritis of the knee. J Orthop Res 2002; 20(1): 108–11PubMedGoogle Scholar
  112. 112.
    Gill ND, Shield A, Blazevich AJ, et al. Muscular and cardiorespiratory effects of pseudoephedrine in human athletes. Br J Clin Pharmacol 2000; 50(3): 205–13PubMedGoogle Scholar

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Authors and Affiliations

  1. 1.School of Exercise Science and Sport ManagementSouthern Cross UniversityLismoreAustralia

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