| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
J Neurophysiol (December 1, 2002). 10.1152/jn.00232.2002
Submitted on 29 March 2002
Accepted on 8 August 2002
Department of Kinesiology and Applied Physiology, University of Colorado, Boulder, Colorado 80309-0354
Hunter, Sandra K.,
Daphne
L. Ryan,
Justus D. Ortega, and
Roger M. Enoka.
Task Differences With the Same Load Torque Alter the Endurance
Time of Submaximal Fatiguing Contractions in Humans. J. Neurophysiol. 88: 3087-3096, 2002. Endurance time,
muscle activation, and mean arterial pressure were measured during two
types of submaximal fatiguing contractions that required each subject
to exert the same net muscle torque in the two tasks. Sixteen men and
women performed isometric contractions at 15% of the maximum voluntary
contraction (MVC) force with the elbow flexor muscles, either by
maintaining a constant force while pushing against a force transducer
(force task) or by supporting an equivalent inertial load while
maintaining a constant elbow angle (position task). The endurance time
for the force task (1402 ± 728 s) was twice as long as that
for the position task (702 ± 582 s, P < 0.05), despite a similar reduction in the load torque at exhaustion for
each contraction. The rate of increase in average electromyographic
activity (EMG, % peak MVC value) for the elbow flexor muscles was
similar for the two tasks. However, the average EMG was greater at
exhaustion for the force task (22.4 ± 1.2%) compared with the
position task (14.9 ± 1.0%, P < 0.05). In
contrast, the rates of increase in the mean arterial pressure, the
rating of perceived exertion, anterior deltoid EMG, and fluctuations in
motor output (force or acceleration) were greater for the position task
compared with the force task (P < 0.05). Furthermore,
the rate of bursts in EMG activity, which corresponded to the transient recruitment of motor units, was greater for the brachialis muscle during the position task. These results indicate that the briefer endurance time for the position task was associated with greater levels
of excitatory and inhibitory input to the motor neurons compared with
the force task.
This article has been cited by other articles:
|
|
 |
|
  S. Baudry, T. Rudroff, L. A. Pierpoint, and R. M. Enoka Load Type Influences Motor Unit Recruitment in Biceps Brachii During a Sustained Contraction J Neurophysiol, September 1, 2009; 102(3): 1725 - 1735. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I.-S. Hwang, Z.-R. Yang, C.-T. Huang, and M.-C. Guo Reorganization of multidigit physiological tremors after repetitive contractions of a single finger J Appl Physiol, March 1, 2009; 106(3): 966 - 974. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. A. Riley, S. Baudry, and R. M. Enoka Reflex Inhibition in Human Biceps Brachii Decreases With Practice of a Fatiguing Contraction J Neurophysiol, November 1, 2008; 100(5): 2843 - 2851. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Hunter, T. Yoon, J. Farinella, E. E. Griffith, and A. V. Ng Time to task failure and muscle activation vary with load type for a submaximal fatiguing contraction with the lower leg J Appl Physiol, August 1, 2008; 105(2): 463 - 472. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Rudroff, D. Staudenmann, and R. M. Enoka Electromyographic measures of muscle activation and changes in muscle architecture of human elbow flexors during fatiguing contractions J Appl Physiol, June 1, 2008; 104(6): 1720 - 1726. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Z. A. Riley, A. H. Maerz, J. C. Litsey, and R. M. Enoka Motor unit recruitment in human biceps brachii during sustained voluntary contractions J. Physiol., April 15, 2008; 586(8): 2183 - 2193. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Klass, M. Levenez, R. M. Enoka, and J. Duchateau Spinal Mechanisms Contribute to Differences in the Time to Failure of Submaximal Fatiguing Contractions Performed With Different Loads J Neurophysiol, March 1, 2008; 99(3): 1096 - 1104. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. M. Enoka and J. Duchateau Muscle fatigue: what, why and how it influences muscle function J. Physiol., January 1, 2008; 586(1): 11 - 23. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. K. Barry and R. M. Enoka The neurobiology of muscle fatigue: 15 years later Integr. Comp. Biol., October 1, 2007; 47(4): 465 - 473. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Rudroff, B. K. Barry, A. L. Stone, C. J. Barry, and R. M. Enoka Accessory muscle activity contributes to the variation in time to task failure for different arm postures and loads J Appl Physiol, March 1, 2007; 102(3): 1000 - 1006. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Hunter, J. M. Schletty, K. M. Schlachter, E. E. Griffith, A. J. Polichnowski, and A. V. Ng Active hyperemia and vascular conductance differ between men and women for an isometric fatiguing contraction J Appl Physiol, July 1, 2006; 101(1): 140 - 150. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. Mottram, K. S. Maluf, J. L. Stephenson, M. K. Anderson, and R. M. Enoka Prolonged Vibration of the Biceps Brachii Tendon Reduces Time to Failure When Maintaining Arm Position With a Submaximal Load J Neurophysiol, February 1, 2006; 95(2): 1185 - 1193. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Iridiastadi and M. A. Nussbaum Muscular Fatigue and Endurance During Intermittent Static Efforts: Effects of Contraction Level, Duty Cycle, and Cycle Time Human Factors: The Journal of the Human Factors and Ergonomics Society, January 1, 2006; 48(4): 710 - 720. [Abstract] [PDF]
|
|
|
|
|
|
C. J. Mottram, E. A. Christou, F. G. Meyer, and R. M. Enoka Frequency Modulation of Motor Unit Discharge Has Task-Dependent Effects on Fluctuations in Motor Output J Neurophysiol, October 1, 2005; 94(4): 2878 - 2887. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Hunter, A. Critchlow, and R. M. Enoka Muscle endurance is greater for old men compared with strength-matched young men J Appl Physiol, September 1, 2005; 99(3): 890 - 897. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Nozaki, K. Nakazawa, and M. Akai Uncertainty of knee joint muscle activity during knee joint torque exertion: the significance of controlling adjacent joint torque J Appl Physiol, September 1, 2005; 99(3): 1093 - 1103. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. S. Maluf and R. M. Enoka Task failure during fatiguing contractions performed by humans J Appl Physiol, August 1, 2005; 99(2): 389 - 396. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. J. Mottram, J. M. Jakobi, J. G. Semmler, and R. M. Enoka Motor-Unit Activity Differs With Load Type During a Fatiguing Contraction J Neurophysiol, March 1, 2005; 93(3): 1381 - 1392. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Place, N. A. Maffiuletti, Y. Ballay, and R. Lepers Twitch potentiation is greater after a fatiguing submaximal isometric contraction performed at short vs. long quadriceps muscle length J Appl Physiol, February 1, 2005; 98(2): 429 - 436. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Hunter, A. Critchlow, and R. M. Enoka Influence of aging on sex differences in muscle fatigability J Appl Physiol, November 1, 2004; 97(5): 1723 - 1732. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Hunter, A. Critchlow, I.-S. Shin, and R. M. Enoka Men are more fatigable than strength-matched women when performing intermittent submaximal contractions J Appl Physiol, June 1, 2004; 96(6): 2125 - 2132. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Hunter, A. Critchlow, I.-S. Shin, and R. M. Enoka Fatigability of the elbow flexor muscles for a sustained submaximal contraction is similar in men and women matched for strength J Appl Physiol, January 1, 2004; 96(1): 195 - 202. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Hunter, R. Lepers, C. J. MacGillis, and R. M. Enoka Activation among the elbow flexor muscles differs when maintaining arm position during a fatiguing contraction J Appl Physiol, June 1, 2003; 94(6): 2439 - 2447. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
