Semi-recumbent ergometer cycling is a common rehabilitation modality after spinal cord injury (SCI). Cycling engages central pattern generators in the spinal cord, which have been identified as a therapeutic target to improve sensorimotor function after paralysis. Functional electrical stimulation (FES) enables stimulating muscles to achieve cycling movement. However, stimulation patterns are not personalised to the individual or task demand. Understanding how muscle activation patterns change across semi-recumbent cycling cadence and power will allow to devise improved, physiologically plausible, control algorithms for FES cycling. Muscle synergies have been deeply investigated in recent years and are the most commonly used method to investigate muscle activation patterns.