From: Doug Skrecky (oberon@vcn.bc.ca)
Date: Tue Sep 05 2000 - 21:34:51 MDT
Citation 1 of 2:
Effects of Resistance Exercise Combined With Moderate
Vascular Occlusion on Muscular Function in Humans
Journal of Applied Physiology 88(6): 2097-106 June 2000
Abstract: Acute and long-term effects of resistance exercise
combined with vascular occlusion on muscular function were
investigated. Changes in integrated electromyogram with
respect to time (iEMG), vascular resistive index, and plasma
lactate concentration were measured in five men either during
or after elbow flexion exercises with the proximal end of the
arm occluded at 0-100 mmHg. The mean iEMG, postexercise
hyperemia, and plasma lactate concentration were all elevated
with the increase in occlusion pressure at a low-intensity exercise,
whereas they were unchanged with the increase in occlusion
pressure at high-intensity exercise. To investigate the long-term
effects of low-intensity exercise with occlusion, older women
(n = 24) were subjected to a 16-wk exercise training for elbow
flexor muscles, in which low-intensity [approximately 50-30%
one repetition maximum (1 RM) exercise with occlusion at
approximately 110 mmHg (LIO), low-intensity exercise without
occlusion (LI), and high- to medium-intensity (approximately
80-50% 1 RM) exercise without occlusion (HI) were performed.
Percent increases in both cross-sectional area and isokinetic
strength of elbow flexor muscles after LIO were larger than those
after LI (P<0.05) and similar to those after HI. The results suggest
that resistance exercise at an intensity even lower than 50% 1 RM
is effective in inducing muscular hypertropy and concomitant
increase in strength when combined with vascular occlusion.
Citation 2 of 2:
Rapid Increase in Plasma Growth Hormone After
Low-Intensity Resistance Exercise With Vascular Occlusion.
Journal of Applied Physiology 88(1): 61-5 January 2000
Abstract: Hormonal and inflammatory responses to low-intensity
resistance exercise with vascular occlusion were studied. Subjects
(n=6) performed bilateral leg extension exercise in the seated
position, with the proximal end of their thigh compressed at 214
+/- 7.7 (SE) mmHg throughout the session of exercise by means
of a pressure tourniquet. Mean intensity and quantity of the exercise
were 20% of 1 repetition maximum and 14 repetitions x 5 sets,
respectively. In each set, the subjects repeated the movement
until exhaustion. Plasma concentrations of growth hormone (GH),
norepinephrine (NE), lactate (La), lipid peroxide (LP), interleukin-6
(IL-6), and activity of creatine phosphokinase (CPK) were measured
before and after the exercise was finished and the tourniquet was
released. Concentrations of GH, NE, and La consistently showed
marked, transient increases after the exercise with occlusion,
whereas they did not change a great deal after the exercise without
occlusion (control) done at the same intensity and quantity. Notably,
concentration of GH reached a level approximately 290 times as
high as that of the resting level 15 min after the exercise. IL-6
concentration showed a much more gradual increase and was
maintained at a slightly higher level than in the control even 24 h
after exercise. Concentrations of LP and CPK showed no significant
change. The results suggest that extremely light resistance exercise
combined with occlusion greatly stimulates the secretion of GH
though regional acculation of metabolites without considerable
tissue damage.
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