Effects of immobilization on electromyogram power spectrum changes during fatigue

  • Jacques Duchateau
  • Karl Hainaut


The maximal force and median frequency (MF) of the electromyogram (EMG) power density spectrum (PDS) have been compared in disused (6 weeks' immobilization) and control (contralateral) human adductor pollicis muscles during fatigue induced by voluntary or electrically-triggered (30 Hz) contractions. The results indicated that after 6 weeks' immobilization, MF was not significantly different in disused and control muscles although the force and integrated EMG were drastically reduced during a maximal voluntary contraction (MVC; by 55% and 45%, respectively,n = 8). During sustained 60 s MVC, the force decreased at the same rate in immobilized and control muscles, but the shift of MF towards lower frequency values was smaller (P< 0.05) in disused muscle as compared to control by (14% vs 28%, respectively). In electrically-induced fatigue, the force decrease and the MF shift were larger after inactivity (41% and 43% in one subject, and 50% and 54% in the other subject, respectively) as compared to control (29% and 34% in one subject, and 37% and 38% in the other subject, respectively). These results emphasize the caution that should be exercised when EMG signals are quantified by computing the power density spectrum. The different effects of fatigue during voluntary and electrically-imposed contractions in disused and control muscles indicated that immobilization induced changes in the neural command for the contraction which compensated, at least in part, for its decreased contractile efficiency and resistance to fatigue.

Key words

Muscle fatigue Immobilization Electromyography Power density spectrum 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Appell HJ (1986) Skeletal muscle atrophy during immobilization. Int J Sports Med 7:1–5Google Scholar
  2. Arendt-Nielsen L, Mills KR (1985) The relationship between mean power frequency of the EMG spectrum and muscle fiber velocity. Electroencephalogr Clin Neurophysiol 60:130–134PubMedGoogle Scholar
  3. Bigland-Ritchie B, Donovan EF, Roussos CS (1981) Conduction velocity and EMG power spectrum changes in fatigue of sustained maximal efforts. J Appl Physiol 51:1300–1305PubMedGoogle Scholar
  4. Bigland-Ritchie B, Jones DA, Woods JJ (1979) Excitation frequency and muscle fatigue: electrical responses during human voluntary and stimulated contractions. Exp Neurol 64:414–427PubMedGoogle Scholar
  5. Booth FW (1982) Effects of limb immobilization on skeletal muscle. J Appl Physiol 52:1113–1118PubMedGoogle Scholar
  6. Booth FW, Seider MJ (1979) Early change in skeletal muscle protein synthesis after limb immobilization of rats. J Appl Physiol 47:974–977Google Scholar
  7. Broman H (1977) An investigation on the influence of a sustained contraction of the succession of action potentials from a single motor unit. Electromyogr Clin Neurophysiol 17:341–358PubMedGoogle Scholar
  8. Davies CTM, Rutherford IC, Thomas DO (1987) Electrically evoked contractions of the triceps surae during and following 21 days of voluntary leg immobilization. Eur J Appl Physiol 56:306–312Google Scholar
  9. De Luca CJ (1984) Myoelectrical manifestations of localized muscular fatigue in humans. CRC Crit Rev Biomed Eng 11:251–279Google Scholar
  10. Duchateau J, Hainaut K (1987) Electrical and mechanical changes in immobilized human muscle. J Appl Physiol 62:2168–2173PubMedGoogle Scholar
  11. Duchateau J, Hainaut K (1990) Effects of immobilization on contractile properties, recruitment and firing rates of human motor units. J Physiol 422:55–65PubMedGoogle Scholar
  12. Fudema JJ, Fizzell JA, Nelson EM (1961) Electromyography of experimentally immobilized skeletal muscles in cats. Am J Physiol 200:963–967PubMedGoogle Scholar
  13. Fuglsang-Frederiksen A, Scheel U (1978) Transient decrease in number of motor units after immobilization in man. J Neurol Neurosurg Psychiatry 41:924–929PubMedGoogle Scholar
  14. Goldspink G (1977) The influence of immobilization and stretch on protein turnover of rat skeletal muscle. J Physiol 264:267–282PubMedGoogle Scholar
  15. Komi PV, Tesch P (1977) EMG frequency spectrum, muscle structure and fatigue during dynamic contractions in man. Eur J Appl Physiol 42:41–50Google Scholar
  16. Lindström L, Petersen I (1981) Power spectra of myoelectric signals: motor unit activity and muscle fatigue. In: Stalberg E, Young R (eds) Clinical neurophysiology. Butterworth, London, pp 66–67Google Scholar
  17. Lindström L, Magnusson R, Petersen I (1970) Muscular fatigue and action potential conduction velocity changes studied with frequency analysis of EMG signals. Electromyogr Clin Neurophysiol 10:341–356Google Scholar
  18. McDougall JD, Ward BR, Sale DG, Sutton JR (1977) Biochemical adaptation of human skeletal muscle to heavy resistance training and immobilization. J Appl Physiol 43:700–703PubMedGoogle Scholar
  19. Maier R, Crockett JL, Simpson DR, Saubert CW, Edgerton VR (1976) Properties of immobilized guinea pig hindlimb muscles. Am J Physiol 231:1520–1526PubMedGoogle Scholar
  20. Mills KR, Edwards RHT (1984) Muscle fatigue in myophosphorylase deficiency: power spectral analysis of the electromyogram. Electroencephalogr Clin Neurophysiol 57:330–335Google Scholar
  21. Naeije M, Zorn H (1982) Relation between EMG power spectrum shifts and muscle fibre action potential conduction velocity changes during local muscular fatigue in man. Eur J Appl Physiol 50:23–33Google Scholar
  22. Sale DG, McComas AJ, McDougall JD, Upton ARM (1982) Neuromuscular adaptation in human thenar muscles following strength training and immobilization. J Appl Physiol 53:419–424PubMedGoogle Scholar
  23. St Pierre D, Gardiner PF (1985) Effect of “disuse” on mammalian fast-twitch muscle: joint fixation compared with neurally applied to tetrodotoxin. Exp Neurol 90:635–651PubMedGoogle Scholar
  24. St Pierre D, Leonard D, Houle R, Gardiner PF (1988) Recovery of muscle from tetrodotoxin-induced disuse and the influence of daily exercise. 2 Muscle enzymes and fatigue characteristics. Exp Neurol 101:327–346PubMedGoogle Scholar
  25. White MJ, Davies CTM (1984) The effects of immobilization, after lower leg fracture, on the contractile properties of human triceps surae. Clin Sci 66:277–282PubMedGoogle Scholar
  26. Zwarts MJ, Arendt-Nielsen (1988) The influence of force and circulation on average muscle fibre conduction velocity during local muscle fatigue. Eur J Appl Physiol 58:278–283Google Scholar
  27. Zwarts MJ, Haeven HTM, Van Weerden TW (1987) The relation between the average muscle fibre conduction velocity and EMG power spectra during isometric contraction, recovery and applied ischemia. Eur J Appl Physiol 56:212–216Google Scholar

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Jacques Duchateau
    • 1
  • Karl Hainaut
    • 1
  1. 1.Laboratory of BiologyUniversité Libre de BruxellesBrusselsBelgium

Personalised recommendations