Exercise-induced muscle injury augments forearm vascular resistance during leg exercise

1998 ◽  
Vol 275 (2) ◽  
pp. H443-H447 ◽  
Author(s):  
Chester A. Ray ◽  
Edward T. Mahoney ◽  
Keith M. Hume
Keyword(s):  
Vascular Resistance ◽  
Muscle Injury ◽  
Forearm Blood Flow ◽  
Maximum Voluntary Contraction ◽  
Knee Extensor ◽  
Voluntary Contraction ◽  
Extensor Muscles ◽  
Exercise Induced ◽  
Knee Extensor Muscles ◽  
Forearm Vascular Resistance

The purpose of the present investigation was to examine the effect of exercise-induced muscle injury on hemodynamic responses during exercise. Ten subjects performed unilateral isometric knee extensions (IKE) at 30% of preinjury maximum voluntary contraction to fatigue and for 3 min before and 48 h after muscle injury. Muscle injury was elicited by performing 8 sets of 10 repetitions of eccentric muscle actions of the knee extensor muscles (i.e., quadriceps muscles) by lowering a weight equivalent to 75% of eccentric maximum load. Exercise time to fatigue for IKE at 30% of maximum voluntary contraction in the injured leg was significantly decreased from preinjury to postinjury IKE (257 ± 21 to 203 ± 23 s; n = 10), but was unchanged in the control leg (244 ± 16 to 254 ± 20 s; n = 7). With the use of a 10-cm visual analog scale, ratings of muscle soreness in the injured leg increased from 0 to 5.1 ± 0.7 cm ( P < 0.001) but were not changed in the control leg (0 both times). Both heart rate and mean arterial pressure responses to exercise were unchanged following muscle injury. Forearm blood flow and forearm vascular resistance were not different at rest and during the first minute of exercise before and after muscle injury. However, after muscle injury, forearm blood flow was significantly lower and forearm vascular resistance was significantly higher ( P < 0.03) during the second and third minutes of exercise. There were no significant changes in any variables with the contralateral control leg. In four subjects, resting magnetic resonance images demonstrated a 23% greater relative cross-sectional area of the knee extensor muscles with an elevated transverse relaxation time in the injured versus control leg. The results indicate that forearm vascular resistance is augmented during isometric knee extension following muscle injury of the knee extensor muscles. The data suggest that muscle injury alters vascular control to non-exercising skeletal muscle during exercise.

Activation varies among the knee extensor muscles during a submaximal fatiguing contraction in the seated and supine postures

2003 ◽  
Vol 95 (4) ◽  
pp. 1515-1522 ◽  
Author(s):  
L Rochette ◽  
S. K. Hunter ◽  
N Place ◽  
R Lepers
Keyword(s):  
Vastus Lateralis ◽  
Maximum Voluntary Contraction ◽  
Knee Extensor ◽  
Voluntary Contraction ◽  
Emg Activity ◽  
Task Failure ◽  
Rate Of Increase ◽  
Extensor Muscles ◽  
Seated Posture ◽  
Knee Extensor Muscles

Ten young men sustained an isometric contraction of the knee extensor muscles at 20% of the maximum voluntary contraction (MVC) torque on three separate occasions in a seated posture. Subjects performed an isometric knee extension contraction on a fourth occasion in a supine posture. The time to task failure for the seated posture was similar across sessions (291 ± 84 s; P > 0.05), and the MVC torque was similarly reduced across sessions after the fatiguing contraction (42 ± 12%). The rate of increase in electromyograph (EMG) activity (%MVC) and torque fluctuations during the fatiguing contractions were similar across sessions. However, the rate of increase in EMG differed among the knee extensor muscles: the rectus femoris began at a greater amplitude (31.5 ± 11.0%) compared with the vastus lateralis and vastus medialis muscles (18.8 ± 5.3%), but it ended at a similar value (45.4 ± 3.1%). The time to task failure and increase in EMG activity were similar for the seated and supine tasks; however, the reduction in MVC torque was greater for the seated posture. These findings indicate that the time to task failure for the knee extensor muscles that have a common tendon insertion did not alter over repeat sessions as had been observed for the elbow flexor muscles (Hunter SK and Enoka RM. J Appl Physiol 94: 108-118, 2003).

Older adults are less steady during submaximal isometric contractions with the knee extensor muscles

2002 ◽  
Vol 92 (3) ◽  
pp. 1004-1012 ◽  
Author(s):  
Brian L. Tracy ◽  
Roger M. Enoka
Keyword(s):  
Maximum Voluntary Contraction ◽  
Knee Extensor ◽  
Voluntary Contraction ◽  
Eccentric Contractions ◽  
Isometric Contractions ◽  
Antagonist Muscle ◽  
Old Adults ◽  
Extensor Muscles ◽  
Young Subjects ◽  
Knee Extensor Muscles

This study compared the steadiness of submaximal contractions with the knee extensor muscles in young and old adults. Twenty young and twenty old subjects underwent assessment of isometric maximum voluntary contraction (MVC), one-repetition maximum (1-RM) strength, and steadiness during isometric, concentric, and eccentric contractions with the knee extensor muscles. The old adults displayed 33% lower MVC force and a 41% lower 1-RM load. The coefficient of variation for force was significantly greater for the old adults during isometric contractions at 2, 5, and 10% of MVC but not at 50% MVC. The decline in steadiness at low forces experienced by the men was marginally greater than that experienced by the women. The steadiness of concentric and eccentric contractions was similar in young and old adults at 5, 10, and 50% of 1-RM load. Old subjects exhibited greater coactivation of an antagonist muscle compared with young subjects during the submaximal isometric and anisometric contractions. These results indicate that, whereas the ability to exert steady submaximal forces with the knee extensor muscles was reduced in old adults, fluctuations in knee joint angle during slow movements were similar for young and old adults.

An Experimental Model of Exercise-Induced Muscle Damage (EIMD) to the Knee Extensor Muscles

1999 ◽  
Vol 9 (2) ◽  
pp. 109
Author(s):  
P. Frémont ◽  
M. Duchesne ◽  
F. Desmeules ◽  
B. Lapointe ◽  
C. H. Côté
Keyword(s):  
Muscle Damage ◽  
Experimental Model ◽  
Knee Extensor ◽  
Extensor Muscles ◽  
Exercise Induced ◽  
Knee Extensor Muscles

Effects of chronic low-frequency electrical stimulation of human knee extensor muscles exposed to static passive stretching

2006 ◽  
Vol 32 (1) ◽  
pp. 74-80 ◽  
Author(s):  
B. S. Shenkman ◽  
E. V. Lyubaeva ◽  
D. V. Popov ◽  
A. I. Netreba ◽  
O. S. Tarasova ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Low Frequency ◽  
Knee Extensor ◽  
Human Knee ◽  
Passive Stretching ◽  
Extensor Muscles ◽  
Knee Extensor Muscles ◽  
Stimulation Of

Intrinsic Properties of the Knee Extensor Muscles After Subacute Stroke

2010 ◽  
Vol 91 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Astrid M. Horstman ◽  
Karin H. Gerrits ◽  
Marijke J. Beltman ◽  
Peter A. Koppe ◽  
Thomas W. Janssen ◽  
...  
Keyword(s):  
Knee Extensor ◽  
Intrinsic Properties ◽  
Subacute Stroke ◽  
Extensor Muscles ◽  
Knee Extensor Muscles

Forearm and finger blood flow responses to passive body tilts

1979 ◽  
Vol 46 (2) ◽  
pp. 288-292 ◽  
Author(s):  
Y. A. Mengesha ◽  
G. H. Bell
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Pulse Rate ◽  
Forearm Blood Flow ◽  
Body Tilt ◽  
Finger Blood Flow ◽  
Arterial Blood ◽  
Forearm Vascular Resistance

Ten to fifteen healthy subjects, ages 18--30 yr, were used to assess the correlation of forearm blood flow with graded passive body tilts and vascular resistance and also to discern the relative effects of body tilts on finger blood flow. In the head-up tilts forearm blood flow and arterial blood pressure fell progressively, whereas forearm vascular resistance and pulse rate increased. In the head-down tilts the forearm blood flow and the arterial blood pressure increased, whereas the forearm vascular resistance and pulse rate decreased. These changes were found to be significantly correlated with the different tilt angles and with one another. In a preliminary study it was found that infrared heating of the carpometacarpal region produced finger vasodilatation similar to the forearm vasodilatation observed by Crockford and Hellon (6). However, unlike forearm blood flow, finger blood flow showed no appreciable response to either the head-up or head-down tilts. This indicates that the sympathetic tone and the volume of blood in the finger are not appreciably altered by this test procedure at least 1 min after the body tilt is assumed.

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