European Journal of Applied Physiology

, Volume 103, Issue 6, pp 677–686 | Cite as

Age- and sex-related differences in muscle activation for a discrete functional task

Original Article


Electromyography (EMG) recordings for a typical 8-h day have indicated that burst activity is greater in old adults compared with young adults; these age-related adaptations might be due to the tasks undertaken. The purpose of the present study was to determine whether EMG burst activity differs between young and old men and women for a discrete task of daily living, and to assess whether the time of day when the task is performed influences the EMG burst patterns. Subjects completed a discrete functional task of a grocery bag carry prior to and following 8 h of daily activity. Surface EMG was recorded from the biceps brachii, triceps brachii, vastus lateralis, and biceps femoris. Spatial and temporal characteristics of the bursts were quantified as a period of EMG activity being greater than 2% maximum EMG and for a duration longer than 0.1 s. Burst activity did not differ between the morning and evening recordings, which indicate that the time of day does not influence burst activity recorded for a discrete task. Although there were no differences in burst number between young (10.9 ± 1.0) and old (11.4 ± 0.7) adults, burst duration and area were 3–7 times larger in old adults compared with young adults. The number of bursts in women (7.9 ± 1.0) were ~85% less compared with men (14.6 ± 0.7), but burst duration and burst area were approximately three times larger in women compared with men. Thus, older adults demonstrate higher levels of burst activity compared with young adults, and these age-related changes in burst activity are augmented in women.


Electromyography Motor unit activity Aged Sex Muscle 



This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) (Edwards and Jakobi), Canadian Foundation for Innovation (CFI) (Jakobi), and the University of Windsor President’s Excellence Postgraduate Scholarship (Harwood). The authors thank Chris Power and CED for contributing to the Custom Script Design for burst analysis. Dr. R.M. Enoka is thanked for insightful scientific question of earlier work that subsequently resulted in this study.


  1. Aagaard P, Simonsen EB, Andersen JL et al (2000) Antagonist muscle coactivation during isokinetic knee extension. Scand J Med Sci Sports 10:58–67PubMedCrossRefGoogle Scholar
  2. Blangsted AK, Hansen K, Jensen C (2003) Muscle activity during computer-based office work in relation to self-reported job demands and gender. Eur J Appl Physiol 89:352–358PubMedCrossRefGoogle Scholar
  3. Candow DG, Chillibeck PD (2005) Differences in size, strength, and power of upper and lower body muscle groups in young and older men. J Gerontol A Biol Sci Med Sci 60:148–156PubMedGoogle Scholar
  4. Dietz V, Fouad K, Bastiaanse CM (2001) Neuronal coordination of arm and leg movements during human locomotion. Eur J Neurosci 14:1906–1914PubMedCrossRefGoogle Scholar
  5. Dipietro L, Caspersen CJ, Ostfeld AM et al (1993) A survey for assessing physical activity among older adults. Med Sci Sports Exerc 25:628–642PubMedGoogle Scholar
  6. Duysens J, Pearson KG (1980) Inhibition of flexor burst generation by loading ankle extensor muscles in walking cats. Brain Res 187:321–332PubMedCrossRefGoogle Scholar
  7. Edwards DL, Jakobi JM (2006) Comparison of daily muscle activity with electromyography in young and old men. Appl Physiol Nutr Metab 31:S22Google Scholar
  8. Edwards DL, Jakobi JM (2007) Characterization of muscular rest periods (gaps) in long-term EMG of older men and women. Med Sci Sports Exerc 39:S269Google Scholar
  9. Harwood B, Edwards DL, Jakobi JM (2007) Quantifying muscular activation and rest in a discrete functional task of older men and women. Med Sci Sports Exerc 29:S267Google Scholar
  10. Kamen G, Sison SV, Du CC et al (1995) Motor unit discharge behavior in older adults during maximal-effort contractions. J Appl Physiol 79:1908–1913PubMedGoogle Scholar
  11. Kern DS, Semmler JG, Enoka RM (2001) Long-term activity in upper- and lower-limb muscles of humans. J Appl Physiol 91:2224–2232PubMedGoogle Scholar
  12. Kingma I, Aalbersberg S, van Dieen JH (2004) Are hamstrings activated to counteract shear forces during isometric knee extension efforts in healthy subjects? J Electromyogr Kinesiol 14:307–315PubMedCrossRefGoogle Scholar
  13. Klein CS, Rice CL, Marsh GD (2001) Normalized force, activation, and coactivation in the arm muscles of young and old men. J Appl Physiol 91:1341–1349PubMedGoogle Scholar
  14. Laursen B, Jensen BR, Ratkevicius A (2001) Performance and muscle activity during computer mouse tasks in young and elderly adults. Eur J Appl Physiol 84:329–336PubMedCrossRefGoogle Scholar
  15. Merletti R, Roy S (1996) Myoelectric and mechanical manifestations of muscle fatigue voluntary contractions. J Orthop Sports Phys Ther 24:342–353PubMedGoogle Scholar
  16. Mork PJ, Westgaard RH (2005) Long-term electromyographic activity in upper trapezius and low back muscles of women with moderate physical activity. J Appl Physiol 99:570–578PubMedCrossRefGoogle Scholar
  17. Nordander C, Hansson GA, Rylander L et al (2000) Muscular rest and gap frequency as EMG measures of physical exposure: the impact of work tasks and individual related factors. Ergonomics 43:1904–1919PubMedCrossRefGoogle Scholar
  18. Paffenbarger Physical Activity Questionnaire (1997) A collection of physical activity questionnaires for health-related research. Med Sci Sports Exerc. A Collection of Physical Activity Questionnaires for Health-Related Research 29: S83–S88Google Scholar
  19. Pearson KG, Collins DF (1993) Reversal of the influence of group Ib afferents from plantaris on activity in medial gastrocnemius muscle during locomotor activity. J Neurophysiol 70:1009–1017PubMedGoogle Scholar
  20. Rice CL (2000) Muscle function at the motor unit level: consequences of aging. Top Geriatr Rehabil 15:70–82Google Scholar
  21. Seidler-Dobrin RD, He J, Stelmach GE (1998) Coactivation to reduce variability in the elderly. Motor Control 2:314–330PubMedGoogle Scholar
  22. Stephens MJ, Yang JF (1999) Loading during the stance phase of walking in humans increases the extensor EMG amplitude but does not change the duration of the step cycle. Exp Brain Res 124:363–370PubMedCrossRefGoogle Scholar
  23. Thorn S, Sogaard K, Kallenberg LA et al (2007) Trapezius muscle rest time during standardised computer work—a comparison of female computer users with and without self-reported neck/shoulder complaints. J Electromyogr Kinesiol 17:420–427PubMedCrossRefGoogle Scholar
  24. Tracy BL, Enoka RM (2002) Older adults are less steady during submaximal isometric contractions with the knee extensor muscles. J Appl Physiol 92:1004–1012PubMedGoogle Scholar
  25. Tracy BL, Maluf KS, Stephenson JL et al (2005) Variability of motor unit discharge and force fluctuations across a range of muscle forces in older adults. Muscle Nerve 32:533–540PubMedCrossRefGoogle Scholar
  26. Veiersted KB, Westgaard RH, Andersen P (1990) Pattern of muscle activity during stereotyped work and its relation to muscle pain. Int Arch Occup Environ Health 62:31–41PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.School of Kinesiology, Faculty of Health SciencesThe University of Western OntarioLondonCanada
  2. 2.Faculty of Human KineticsUniversity of WindsorWindsorCanada
  3. 3.Faculty of Health and Social DevelopmentUniversity of British Columbia OkanaganKelownaCanada

Personalised recommendations