Effects of exhaustive stretch-shortening cycle exercise on muscle blood flow during exercise.
OBJECTIVE
The influence of exhaustive stretch-shortening cycle exercise (SSC) on skeletal muscle blood flow (BF) during exercise is currently unknown.


METHODS
Quadriceps femoris (QF) BF was measured in eight healthy men using positron emission tomography before and 3 days after exhaustive SSC exercise. The SSC protocol consisted of maximal and submaximal drop jumps with one leg. Needle biopsies of the vastus lateralis muscles were taken immediately and 2 days after SSC for muscle endothelial nitric oxide synthase (eNOS) and interleukin-1-beta (IL-1beta) mRNA level determinations.


RESULTS
All subjects reported subjective muscle soreness after SSC (P < 0.001), which was well in line with a decrease in maximal isometric contraction force (MVC) and increase in serum creatine kinase activity (CK) (P = 0.018). After SSC muscle BF was 25% higher in entire QF (P = 0.043) and in its deep and superficial muscle regions, whereas oxygen uptake remained unchanged (P = 0.893). Muscle biopsies revealed increased IL-1beta (30 min: 152 +/- 75%, P = 0.012 and 2 days: 108 +/- 203%, P = 0.036) but decreased or unchanged eNOS (30 min; -21 +/- 57%, P = 0.050 and 2 days: +101 +/- 204%, P = 0.779) mRNA levels after SSC.


CONCLUSIONS
It was concluded that fatiguing SSC exercise induces increased muscle BF during exercise, which is likely to be associated with pro-inflammatory processes in the exercised muscle.
Laaksonen
M S
MS
Turku PET Centre, University of Turku, Turku, Finland. marko.laaksonen@miun.se
Kivelä
R
R
Kyröläinen
H
H
Sipilä
S
S
Selänne
H
H
Lautamäki
R
R
Nuutila
P
P
Knuuti
J
J
Kalliokoski
K K
KK
Komi
P V
PV
D000328:Adult; D001706:Biopsy; D003402:Creatine Kinase / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics; D007537:Isometric Contraction; D008297:Male; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics; D010100:Oxygen / Q000378:metabolism; D049268:Positron-Emission Tomography; D012333:RNA, Messenger / Q000032:analysis; D012039:Regional Blood Flow / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric
D007375:Interleukin-1; D012333:RNA, Messenger; D052250:Nitric Oxide Synthase Type III; D003402:Creatine Kinase; D010100:Oxygen