Introduction: Effects of haemophilic arthropathy on neuromuscular control during gait are currently unknown. Aims: (a) To assess how haemophilic arthropathy affects the complexity of neuromuscular control during gait; (b) To investigate the relationship between complexity of neuromuscular control and joint impairment. Methods: Thirteen control subjects (CG) walked overground at their preferred and a slow velocity and thirteen people with haemophilic arthropathy (PWHA) walking at their preferred velocity. Surface electromyography (EMG) was collected from eleven leg muscles. Electromyography variance explained by muscle synergies (sets of co-activated muscles that can be recruited by a single signal) was calculated by the total variance accounted (tVAF). Three measures were used to evaluate complexity of neuromuscular control: (a) the number of synergies required for tVAF > 90%, (b) tVAF as a function of the number of muscle synergies, and (c) the dynamic mot