Muscle Blood Supply During Prolonged Static Voluntary Contractions

It is known that metabolic activity of muscle cells even in one separate muscle differs. If VO 2 rate differs between muscle’s motor units, then blood flow through capillaries supplying muscle cells must be regulated according to their metabolic activity. The aim of this study was to evaluate muscle blood flow and compare it with active muscle cell metabolic activity during muscle prolonged static voluntary contraction with different contraction forces. In this study participated 37 healthy untrained people in age 24 – 36. Investigations were performed on the forearm muscles using hand grip exercises with 10% and 15% of maximal voluntary contraction (MVC) Volume blood flow in the forearm segment (I) and capillary filtration coefficient (CFC) were measured using venous occlusion plethysmographic device “KPOBOTOK-4”. VO 2 and lactate delivery (La) were calculated from pO 2 and lactate concentration arterio-venous differences and I in every controlled moment. pH and pO 2 was measured using bioanaliser ABC-1”RADIOMETER”. Lactate concentration was measured using BIOSEN C-line “EKF diagnostic” device. During 10% MVC it was shown that I, VO 2 , La and CFC till the cessation of exercise caused by exhaustion which takes 42±1,1min stabilize on appropriate level not reaching maximal possible values. Increasing contraction force only for 5% it is to 15% MVC all examined parameters during exercise till exhaustion which takes 12±0,8 min, increases and at moment of cessation of exercise reaches their maximal values. Increasing of blood supply and VO 2 during 15% MVC did not provide prolonged forearm contraction and exhaustion occurs more than 3 times quicker neither during 10% MVC.