Blood circulation of patellar and achilles tendons during contractions and heating.
OBJECTIVE
Recent studies using ultrasonography have demonstrated that training-induced changes in the mechanical properties of tendons in plantar flexors (i.e., Achilles tendon) are lower than those in knee extensors (i.e., patellar tendon). However, the mechanisms for these phenomena are unknown. The purpose of this study was to compare changes in blood circulation of patellar and Achilles tendons by repeated muscle contractions and heating.


METHODS
Eleven healthy males participated in this study. During and after repeated muscle contractions (50 repetitions at 50% of the isometric maximum voluntary contraction for 3 s with 3-s relaxations) and heating (20 min), blood volume (total hemoglobin (THb)) and oxygen saturation (StO2) of the patellar and Achilles tendons were measured using red laser lights.


RESULTS
During repeated muscle contractions, StO2 of the patellar tendon decreased significantly, but that of the Achilles tendon did not. During heating, THb and StO2 increased significantly for both tendons. Increases in THb and StO2 of the patellar tendon were significantly higher than those of the Achilles tendon (both P < 0.001).


CONCLUSIONS
These results demonstrated that changes in blood circulation of the patellar tendon during exercise and heating were higher than those of the Achilles tendon. This result appears to be related to the differences in the plasticity of the mechanical properties of the patellar and Achilles tendons.
Department of Life Science, University of Tokyo, Meguro, Tokyo, Japan. kubo@idaten.c.u-tokyo.ac.jp
Keitaro
K
Kubo
Toshihiro
T
Ikebukuro
D000125:Achilles Tendon / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000502:physiology; D000328:Adult; D006358:Hot Temperature; D006801:Humans; D007259:Infrared Rays; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D010101:Oxygen Consumption; D017847:Patellar Ligament / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000502:physiology; D014463:Ultrasonography