Poor correlations between isometric tests and dynamic performance: relationship to muscle activation

  • Aron J. Murphy
  • Greg J. Wilson
Original Article


The purpose of this research was to perform isometric tests at two joint angles and examine their relationship to dynamic performance. In addition, electromyograph data were collected from the triceps brachii and pectoralis major muscles to compare underlying neural characteristics between the isometric tests and dynamic movement. A group of 24 healthy male subjects performed two isometric tests in a bench press position, at elbow angles of 90 and 120°. From these data, the maximal force and rate of force development were determined. In addition, each subject performed a seated medicine ball throw as a measure of dynamic upper body performance. Correlations showed that isometric measurements of force (r = 0.47–0.55) and rate of force development (r = 0.08–0.31) were poor predictors of dynamic performance. The angle of isometric assessment had little effect on the relationship between the tests and measurements of performance. The myo-electric data was processed in terms of the integrated electromyogram and the Fourier transformed frequency spectrum. These data demonstrated differences in the neural activation patterns of the musculature, between the isometric 90° test and the medicine ball throw. The poor relationship between isometric tests and medicine ball performance was consequently, at least partially, attributed to differing motor unit activation patterns between isometric and dynamic movement. The results of this research strongly suggest that isometric tests have limited value when assessing dynamic upper body performance.

Key words

Upper body Muscle function Median frequency 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bemben MG, Clasey JL, Massey BH (1990) The effect of the rate of muscle contraction on the force-time curve parameters of male and female subjects. Res. Q 61:96–99Google Scholar
  2. Bigland Ritchie B, Johansson R, Lippold J, Wood JJ (1982) Changes of single motor unit firing rates during sustained maximal voluntary contractions. J Appl Physiol 328:27–28Google Scholar
  3. Delagi G, Perotto B (1974) Anatomic guide for the electromyographer. Thomas, Springfield, Ill, pp 74–89Google Scholar
  4. Fugslang-Frederiksen A. Reneger J (1988) The motor unit firing rate and the power spectrum of EMG in humans. Electroencephalogr Clin Neurophysiol 70:68–72CrossRefGoogle Scholar
  5. Gillespie J, Keenum S (1987) A validity and reliability analysis of the seated shotput as a test of power. J Hum Mov Stud 13:97–105Google Scholar
  6. Hakkinen K (1993) Neuromuscular fatigue and recovery in male and female athletes during heavy resistence exercise. Int J Sports Med 14:53–59PubMedGoogle Scholar
  7. Hakkinen K, Komi PV, Kauhanen H (1986) Electromyographic and force production characteristics of leg extensor muscles of elite weight lifters during isometric, concentric, and various stretchshortening cycle exercises. Int J Sports Med 7:144–151PubMedGoogle Scholar
  8. Hakkinen K, Pakarinen A, Alen M, Kauhanen H, Komi PV (1987) Relationships between training volume, physical performance capacity, and serum hormone concentrations during prolonged training in elite weight lifters. Int J Sports Med 8:61–65PubMedGoogle Scholar
  9. Jaric S, Ristanovic D, Corcoss DM (1989) The relationship between muscle kinetic parameters and kinematic variables in a complex movement. Eur J Appl Physiol 59:370–376CrossRefGoogle Scholar
  10. Lago P, Jones N (1977) Effect of motor unit firing time statistics on EMG spectra. Med Biol Eng Comput 15:648–655PubMedGoogle Scholar
  11. Lindstrom L, Magnusson R. Petersen I (1970) Muscular fatigue and action potential changes studied with frequency analysis of EMG signals. Electromyogr Clin Neurophysiol 57:341–356Google Scholar
  12. Mero A, Luhtanen P, Viitasalo JT, Komi PV (1981) Relationship between the maximal running velocity, muscle fiber characteristics, force production and force relaxation of sprinters. Scand J Sports Sci 3:16–22Google Scholar
  13. Murphy AJ, Wilson GJ, Pryor JF (1994) The use of the iso-inertial force mass relationship in the prediction of dynamic human performance. Eur J Appl Physiol 69:250–257CrossRefGoogle Scholar
  14. Murphy AJ, Wilson GJ, Pryor JF, Newton RU (1995) Isometric assessment of muscular function: the effect of joint angle. J Appl. Biomech 11:205–215Google Scholar
  15. Nakazawa K, Kawakami Y, Fukunaga T, Yano H, Miyashita M (1993) Differences in activation patterns in elbow flexor muscles during isometric, concentric and eccentric contractions. Eur J Appl Physiol 66:214–220CrossRefGoogle Scholar
  16. Okada M (1987) Effects of muscle length on surface EMG wave forms in isometric contractions. Eur J Appl Physiol 56:482–486CrossRefGoogle Scholar
  17. Otnes RK, Enochson L (1972) Digital time series analysis. Wiley and Sons, New York, pp 200–206.Google Scholar
  18. Person R (1974) Rhythmic activity of a group of human motoneurons during voluntary contraction of muscle. Electroencephalogr Clin Neurophysiol 36:585–595PubMedCrossRefGoogle Scholar
  19. Pryor JF, Wilson GJ, Murphy AJ (1994) The effectiveness of eccentric, concentric and isometric rate of force development tests. J Hum Mov Stud 27:153–172Google Scholar
  20. Ryushi T, Hakkinen K, Kauhanen H, Komi PV (1988) Muscle fibre characteristics, muscle cross-sectional area and force production in strength athletes, physically active males and females. Scand J Sports Sci 10:7–15Google Scholar
  21. Sale DG (1991) Testing strength and power. In: MacDougall J, Wenger H, Green H (eds) Physiological testing of the high performance athlete, 2nd edn. Human Kineics, Champaign, Ill, pp 21–106.Google Scholar
  22. Sale DG, Martin JE, Moroz DE (1992) Hypertrophy without increased isometric strength after weight training. Eur J Appl Physiol 64:51–55CrossRefGoogle Scholar
  23. Tidow G (1990) Aspects of strength training in athletics. New Stud Athletics 1:93–110Google Scholar
  24. Viitasalo JT (1982) Effects of pretension on isometric force production. Int J Sports Med 3:149–152PubMedCrossRefGoogle Scholar
  25. Viitasalo JT, Aura O (1984) Seasonal fluctuation of force production in high jumpers. Can J Appl Sports Sci 9:209–213Google Scholar
  26. Viitasalo JT, Saukkonen S, Komi PV (1980) Reproducibility of measurements of selected neuromuscular performance variables in man. Electromyogr Clin Neurophysiol 20:487–501PubMedGoogle Scholar
  27. Viitasalo JT, Hakkinen K, Komi PV (1981) Isometric and dynamic force production and muscle fibre composition in man. J Hum Mov Stud 7:199–209Google Scholar
  28. Wilson GJ, Wood GA, Elliot BC (1991) The performance augmentation achieved from the use of the stretch shorten cycle: the neuromuscular contribution. Aust J Sci Med Sport 23:96–100Google Scholar
  29. Wilson GJ, Newton RU, Murphy AJ, Humphries B (1993) The optimal training load for the development of dynamic athletic performance. Med Sci Sports Exerc 25:1279–1286PubMedGoogle Scholar
  30. Young WB, Bilby GE (1993) The effect of voluntary effort to influence speed of contraction on strength, muscular power and hypertrophy development. J Strength Cond Res 7:172–178CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 1996

Authors and Affiliations

  • Aron J. Murphy
    • 1
  • Greg J. Wilson
    • 1
  1. 1.The Centre for Exercise Science and Sport ManagementSouthern Cross UniversityLismoreAustralia

Personalised recommendations