Blood Flow Restriction Training in Knee Arthropathy

H-reflex is a validated neurophysiological indicator for evaluating spinal-level AMI after knee surgery which is applied to assess resting spinal reflex excitability of the knee extensor motor pool vastus medialis.

Unit of Measure: Ratio (dimensionless)

Knee proprioceptive acuity was evaluated using a calibrated isokinetic dynamometer. Participants were blindfolded to exclude visual interference and seated with the tested lower limb securely strapped to the dynamometer lever arm. The knee was passively positioned at three target flexion angles (30°, 60°, and 90°). After passive positioning and a 3-second holding phase, participants actively reproduced the perceived target angle independently. Absolute angular error was calculated as the absolute discrepancy between the preset target angle and the actively reproduced angle.

Unit of Measure: Degrees (°)

Cortical somatosensory afferent function was assessed via tibial nerve somatosensory evoked potentials (SEP). The P40 latency was defined as the time interval from stimulus onset to the occurrence of the P40 positive wave, representing the conduction efficiency and temporal characteristics of peripheral proprioceptive signals transmitting to the primary somatosensory cortex.

Unit of Measure: Milliseconds (ms)

Central sensory integration plasticity was assessed via tibial nerve somatosensory evoked potentials (SEP). The N45-P40 peak-to-peak amplitude was calculated to evaluate cortical sensory gain and central inhibitory/excitatory balance.

Unit of Measure: Microvolts (μV)

Quadriceps rapid torque development rate (RTD) was measured to quantify the efficiency of central motor unit recruitment and neuromuscular rapid-driving capability. Quadriceps RTD was calculated as the rate of torque increase within the early contraction phase, reflecting the recruitment efficacy of high-threshold type II muscle fibers and synchronous firing of motor units.

Unit of Measure: Nm/s