The rapid advancement of electromyography (EMG) technology facilitates measurement of muscle activity outside the laboratory during daily life. The purpose of this study was to determine whether bursts in EMG recorded over a typical 8-hour day differed between young and old males and females. Muscle activity was recorded from biceps brachii, triceps brachii, vastus lateralis, and biceps femoris of 16 young and 15 old adults using portable surface EMG. Old muscles were active 16–27% of the time compared to 5–9% in young muscles. The number of bursts was greater in old than young adults and in females compared to males. Burst percentage and mean amplitude were greater in the flexor muscles compared with the extensor muscles. The greater burst activity in old adults coupled with the unique activity patterns across muscles in males and females provides further understanding of how changes in neuromuscular activity effects age-related functional decline between the sexes. 1. Introduction Accelerometers, pedometers, and global position system (GPS) have become familiar tools for assessing age-related changes in mobility and physical activity during daily life [1, 2], but these devices provide no indication of muscle activity governing movement. Laboratory studies using electromyography (EMG) have provided considerable understanding of age-related changes in muscle activity for simple isometric and anisometric contractions [3–5], gait [6], and discrete tasks [7] executed under experimental constraints. With the advancement of technology, portable EMG devices now offer a means to characterize muscle activity (bursts) and quiescence (gaps) over long durations outside the laboratory, enabling discrete measurement of neuromuscular control within the environmental context of daily life [8, 9]. Quantification of gaps in EMG for a discrete task and during daily life activities, in young and old adults, suggests muscle quiescence decreases in old adults and is less in women compared with men [10]. For a discrete task when the EMG is quantified through bursts, muscle activity increases in old adults relative to young adults and is also greater in women [8, 11]. Together, measurement of bursts and gaps for a discrete task, such as carrying a bag of groceries, suggests that muscles are active more often and “rest” less in older adults and women. Age-related remodeling [12, 13], decreased muscle strength [3, 14, 15], and greater declines in performance for fast velocity relative to slow velocity movements [16, 17] likely predispose old adults to increased bursts to
References
[1]
J. S. Frank and A. E. Patla, “Balance and mobility challenges in older adults: implications for preserving community mobility,” The American Journal of Preventive Medicine, vol. 25, no. 3, pp. 157–163, 2003.
[2]
O. Theou, J. M. Jakobi, A. A. Vandervoort, and G. R. Jones, “A comparison of physical activity (PA) assessment tools across levels of frailty,” Archives of Gerontology and Geriatrics, vol. 54, no. 3, pp. e307–e314, 2012.
[3]
B. H. Dalton, J. M. Jakobi, B. L. Allman, and C. L. Rice, “Differential age-related changes in motor unit properties between elbow flexors and extensors,” Acta Physiologica, vol. 200, no. 1, pp. 45–55, 2010.
[4]
R. M. Enoka, E. A. Christou, S. K. Hunter et al., “Mechanisms that contribute to differences in motor performance between young and old adults,” Journal of Electromyography and Kinesiology, vol. 13, no. 1, pp. 1–12, 2003.
[5]
B. Harwood, D. L. Edwards, and J. M. Jakobi, “Age independent and position-dependent alterations in motor unit activity of the biceps brachii,” European Journal of Applied Physiology, vol. 110, no. 1, pp. 27–38, 2010.
[6]
A. Schmitz, A. Silder, B. Heiderscheit, J. Mahoney, and D. G. Thelen, “Differences in lower-extremity muscular activation during walking between healthy older and young adults,” Journal of Electromyography and Kinesiology, vol. 19, no. 6, pp. 1085–1091, 2009.
[7]
S. Morrison and J. Sosnoff, “Age-related changes in the adaptability of neuromuscular output,” Journal of Motor Behavior, vol. 41, no. 3, pp. 274–283, 2009.
[8]
J. M. Jakobi, D. L. Edwards, and D. M. Connelly, “Utility of portable electromyography for quantifying muscle activity during daily use,” Gerontology, vol. 54, no. 5, pp. 324–331, 2008.
[9]
O. Theou, S. H. Bruce, K. Roland, G. R. Jones, and J. M. Jakobi, “Portable electromyography: application for understanding muscle function of daily life in older adults,” Gerontechnology, vol. 10, no. 3, pp. 146–156, 2011.
[10]
B. Harwood, D. L. Edwards, and J. M. Jakobi, “Age- and sex-related differences for electromyography gaps during daily activity and a discrete task,” Gait and Posture, vol. 34, no. 1, pp. 6–12, 2011.
[11]
B. Harwood, D. L. Edwards, and J. M. Jakobi, “Age- and sex-related differences in muscle activation for a discrete functional task,” European Journal of Applied Physiology, vol. 103, no. 6, pp. 677–686, 2008.
[12]
J. G. Ryall, J. D. Schertzer, and G. S. Lynch, “Cellular and molecular mechanisms underlying age-related skeletal muscle wasting and weakness,” Biogerontology, vol. 9, no. 4, pp. 213–228, 2008.
[13]
A. A. Vandervoort, “Aging of the human neuromuscular system,” Muscle and Nerve, vol. 25, no. 1, pp. 17–25, 2002.
[14]
W. R. Frontera, V. A. Hughes, R. A. Fielding, M. A. Fiatarone, W. J. Evans, and R. Roubenoff, “Aging of skeletal muscle: a 12-yr longitudinal study,” Journal of Applied Physiology, vol. 88, no. 4, pp. 1321–1326, 2000.
[15]
V. A. Hughes, W. R. Frontera, M. Wood et al., “Longitudinal muscle strength changes in older adults: influence of muscle mass, physical activity, and health,” Journals of Gerontology, vol. 56, no. 5, pp. B209–B217, 2001.
[16]
D. G. Candow and P. D. Chilibeck, “Differences in size, strength, and power of upper and lower body muscle groups in young and older men,” Journals of Gerontology, vol. 60, no. 2, pp. 148–156, 2005.
[17]
J. K. Petrella, J.-S. Kim, S. C. Tuggle, S. R. Hall, and M. M. Bamman, “Age differences in knee extension power, contractile velocity, and fatigability,” Journal of Applied Physiology, vol. 98, no. 1, pp. 211–220, 2005.
[18]
N. A. Lynch, E. J. Metter, R. S. Lindle et al., “Muscle quality. I. Age-associated differences between arm and leg muscle groups,” Journal of Applied Physiology, vol. 86, no. 1, pp. 188–194, 1999.
[19]
S. Trappe, P. Gallagher, M. Harber, J. Carrithers, J. Fluckey, and T. Trappe, “Single muscle fibre contractile properties in young and old men and women,” Journal of Physiology, vol. 552, no. 1, pp. 47–58, 2003.
[20]
D. S. Kern, J. G. Semmler, and R. M. Enoka, “Long-term activity in upper- and lower-limb muscles of humans,” Journal of Applied Physiology, vol. 91, no. 5, pp. 2224–2232, 2001.
[21]
J. G. Semmler, D. V. Kutzscher, and R. M. Enoka, “Limb immobilization alters muscle activation patterns during a fatiguing isometric contraction,” Muscle and Nerve, vol. 23, no. 9, pp. 1381–1392, 2000.
[22]
R. E. Brown, D. L. Edwards, and J. M. Jakobi, “Sex differences in force steadiness in three positions of the forearm,” European Journal of Applied Physiology, vol. 110, no. 6, pp. 1251–1257, 2010.
[23]
L. Dipietro, C. J. Caspersen, A. M. Ostfeld, and E. R. Nadel, “A survey for assessing physical activity among older adults,” Medicine and Science in Sports and Exercise, vol. 25, no. 5, pp. 628–642, 1993.
[24]
O. Theou, G. R. Jones, A. A. Vandervoort, and J. M. Jakobi, “Daily muscle activity and quiescence in non-frail, pre-frail, and frail older women,” Experimental Gerontology, vol. 45, no. 12, pp. 909–917, 2010.
[25]
O. Theou, Z. Soon, S. Filek et al., “Changing the sheets: a new system to reduce strain during patient repositioning,” Nursing Research, vol. 60, no. 5, pp. 302–308, 2011.
[26]
H. J. Hermens, G. Rau, C. Disselhorst-Klug, and B. Freriks, Surface ElectroMyoGraphy: Application Areas and Parameters, proceedings of the third general SENIAM workshop, Roessingh Research and Development, Aachen, Germany, 1998.
[27]
W. R. Frontera, V. A. Hughes, K. J. Lutz, and W. J. Evans, “A cross-sectional study of muscle strength and mass in 45- to 78-yr-old men and women,” Journal of Applied Physiology, vol. 71, no. 2, pp. 644–650, 1991.
[28]
T. J. Doherty, D. W. Stashuk, and W. F. Brown, “Determinants of mean motor unit size: impact on estimates of motor unit number,” Muscle and Nerve, vol. 16, no. 12, pp. 1326–1331, 1993.
[29]
H. Kinoshita, P. R. Francis, T. Murase, S. Kawai, and T. Ogawa, “The mechanical properties of the heel pad in elderly adults,” European Journal of Applied Physiology and Occupational Physiology, vol. 73, no. 5, pp. 404–409, 1996.
[30]
B. Mierzejewska-Krzyzowska, H. Drzymala-Celichowska, and J. Celichowski, “Gender differences in the morphometric properties of muscle fibres and the innervation ratio of motor units in rat medial gastrocnemius muscle,” Journal of Veterinary Medicine, vol. 40, no. 4, pp. 249–255, 2011.
[31]
D. G. Bell and I. Jacobs, “Electro-mechanical response times and rate of force development in males and females,” Medicine and Science in Sports and Exercise, vol. 18, no. 1, pp. 31–36, 1986.
[32]
H. Valkeinen, J. Ylinen, E. M？lki？, M. Alen, and K. H？kkinen, “Maximal force, force/time and activation/coactivation characteristics of the neck muscles in extension and flexion in healthy men and women at different ages,” European Journal of Applied Physiology, vol. 88, no. 3, pp. 247–254, 2002.
[33]
J. C. Ives, W. P. Kroll, and L. L. Bultman, “Rapid movement kinematic and electromyographic control characteristics in males and females,” Research Quarterly for Exercise and Sport, vol. 64, no. 3, pp. 274–283, 1993.
[34]
R. M. Andela, A. Dijkstra, J. P. J. Slaets, and R. Sanderman, “Prevalence of frailty on clinical wards: description and implications,” International Journal of Nursing Practice, vol. 16, no. 1, pp. 14–19, 2010.
[35]
R. E. Hubbard and K. Rockwood, “Frailty in older women,” Maturitas, vol. 69, no. 3, pp. 203–207, 2011.
