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

Abstract

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.

Keywords

Electromyography Motor unit activity Aged Sex Muscle 

Notes

Acknowledgments

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.

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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

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