BACKGROUND: An elevated intramuscular pressure during a single forearm isometric muscle contraction may restrict muscle @entity450 . However, during repeated isometric exercise, it is unclear to what extent mechanical compression and muscle vasodilatation contribute to the magnitude and time course of beat-to-beat limb hemodynamics, due to alterations in leg vascular conductance (LVC). METHODS: In eight healthy male subjects, the time course of both beat-to-beat leg blood flow (LBF) and LVC in the femoral artery was determined between repeated 10-s isometric thigh muscle contractions and 10-s @entity121 (a duty cycle of 20  s) for steady-state 120  s at five target workloads (10, 30, 50, 70, and 90  % of maximum @entity2472 (MVC)). The ratio of restricted LBF due to mechanical compression across workloads was determined by the formula (relaxation LBF   -   contraction LBF)/relaxation LBF (%). RESULTS: The exercise protocol was performed completely by all subjects ( <=50  % MVC), seven subjects ( <=70  % MVC), and two subjects ( <=90  % MVC). During a 10-s isometric muscle contraction, the time course in both beat-to-beat LBF and LVC displayed a fitting curve with an exponential increase (P   <   0.001, r (2)   >=    0.956) at each workload but no significant difference in mean LBF across workloads and pre-exercise. During a 10-s @entity121 , the time course in both beat-to-beat LBF and LVC increased as a function of workload, followed by a linear decline (P   <   0.001, r (2)   >=    0.889), that was workload-dependent, resulting in mean LBF increasing linearly across workloads (P   <   0.01, r (2)   =   0.984). The ratio of restricted LBF can be described as a single exponential decay with an increase in workload, which has inflection point distinctions between 30 and 50  % MVC. CONCLUSIONS: In a 20-s duty cycle of steady-state repeated @entity2472 , the post-contraction @entity450 (magnitude of both LBF and LVC) during @entity121 was in proportion to the workload, which is in agreement with previous findings. Furthermore, time-dependent beat-to-beat muscle vasodilatation was seen, but not restricted, during @entity2472 through all target workloads. Additionally, the relative contribution of mechanical obstruction and vasodilatation to the @entity450 observed in the repeated isometric exercise protocol was non-linear with regard to workload. In combination with repeated isometric exercise, the findings could potentially prove to be useful indicators of circulatory adjustment by mechanical compression for muscle-related disease.

Mechanical compression during repeated sustained XXXX and hyperemic recovery in healthy young males.

@entity121 :: ('MESH:D009135', 'Disease') :: ['muscle relaxation'] @entity450 :: ('MESH:D006940', 'Disease') :: ['hyperemia'] @entity2472 :: ('MESH:C536214', 'Disease') :: ['voluntary contraction', 'isometric muscle contractions']
@entity2472 :: (MESH:C536214,Disease) :: ['isometric muscle contractions']
