Purpose: In the present study, five FES profiles were compared in order to find the best combination of activeperiod and burst frequency that might artificially sustain muscle contraction for the longest time with the lowest knee joint variation. Methods: Spinal cord injured volunteers (N=10) participated in this study. The frequency of each FES profile was 1 kHz with variable pulse active period (100 μs or 200 μs) and pulse inactive period (900 μs or 800 μs). The setup burst frequencies had either 50 Hz (3 ms active time and 17 ms rest time) or 70 Hz (3 ms active time and 11 ms rest time). Results: The best results were obtained to FES profiles P2 (burst frequency of 70 Hz and pulse active period of 100 μs), P3 (burst frequency of 50 Hz and pulse active period of 200 μs) and P4 (burst frequency of 70 Hz and pulse active period of 200 μs). 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