Determinants of the daily rhythm of blood fluidity.

Background: Numerous processes in the living body exhibit daily rhythmicity. In this study, we characterized a daily rhythm of blood fluidity and identified its determinants.

Methods: The subjects were nine young males.

Control of heart rate variability by cardiac parasympathetic nerve activity during voluntary static exercise in humans with tetraplegia.

Heart rate (HR) is controlled solely by via cardiac parasympathetic outflow in tetraplegic individuals, who lack supraspinal control of sympathetic outflows and circulating catecholamines but have intact vagal pathways. A high-frequency component (HF; at 0.15-0.

Vastus lateralis oxygenation during prolonged cycling in healthy males.

This study examined the relationship between acute cardiorespiratory and muscle oxygenation and blood volume changes during prolonged exercise. Eight healthy male volunteers (mean maximum oxygen uptake VO(2max) = 41.6 +/- 2.

Cardiovascular control during voluntary static exercise in humans with tetraplegia.

The purpose of the present study was 1) to investigate whether an increase in heart rate (HR) at the onset of voluntary static arm exercise in tetraplegic subjects was similar to that of normal subjects and 2) to identify how the cardiovascular adaptation during static exercise was disturbed by sympathetic decentralization. Mean arterial blood pressure (MAP) and HR were noninvasively recorded during static arm exercise at 35% of maximal voluntary contraction in six tetraplegic subjects who had complete cervical spinal cord injury (C(6)-C(7)). Stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) were estimated by using a Modelflow method simulating aortic input impedance from arterial blood pressure waveform.

Decreased cortical excitability during motor imagery after disuse of an upper limb in humans.

Objective: The present study investigated the effect of joint immobilization on corticomotoneuronal excitability to only intracortical input from a hierarchical level above the primary motor cortex.

Methods: Motor evoked potentials (MEPs) and H-reflexes in the flexor carpi radialis muscle were elicited from 8 orthopedic patients with splints and 8 healthy volunteers. Each patient was examined on the day of splint removal (disuse stage) and 2 months after that day (recovery stage).

Electromechanical delay after ACL reconstruction: an innovative method for investigating central and peripheral contributions.

Objectives: The purpose of this study was to investigate the electromechanical properties of atrophied muscle in patients with anterior cruciate ligament (ACL) reconstruction and to examine the relationship of changes in these properties for a voluntarily elicited maximal isometric contraction and peripherally stimulated twitch contraction.

Background: It is not known if, following ACL reconstruction, a prolonged reaction time to a sudden stimulus is due to impaired proprioception in the knee joint, a prolonged processing interval in the central nervous system, or a greater elasticity in the series elastic component of the quadriceps femoris.

Methods: Seventeen patients were recruited 2 to 3 months following a unilateral ACL reconstruction.

Anterior cruciate ligament injury in recreational alpine skiers: analysis of mechanisms and strategy for prevention.

Between 1995 and 1997, a retrospective survey was conducted in Japan to classify the types of injuries sustained by recreational alpine skiers. The purpose of this study was to investigate the causes and mechanisms of lower-extremity equipment-related (LEER) anterior cruciate ligament (ACL) injury in this population. Seventy-seven (96%) of the 80 respondents reported that their ski bindings did not release their ski boots at the time of their accident, and 30 respondents (38%) reported functional failure of their ski bindings, or that the ski boots came off.