Neuromuscular control during gait in people with haemophilic arthropathy.
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 motor control index (Walk-DMC). Impairment of ankle and knee joints was determined by the Haemophilia Joint Health Score (HJHS).


RESULTS
The same number of the muscle synergies was found for each group (P > 0.05). For both walking velocities tested, tVAF1 was higher in PHWA (P < 0.05). The Walk-DMC of PWHA was lower than that of the CG for both walking velocities (P < 0.05). For PWHA, no significant correlation was found between HJHS (sum knee and ankle) and Walk-DMC index (r = -0.32, P = 0.28).


CONCLUSIONS
These results indicate differences between PWHA and CG in the neuromuscular control of gait. The Walk-DMC and tVAF1 may be useful measures to assess changes in neuromuscular control in response to treatment.
['Cruz-Montecinos|Carlos|C|https://orcid.org/0000-0002-3835-3368', 'Pérez-Alenda|Sofía|S|https://orcid.org/0000-0002-0841-5767', 'Cerda|Mauricio|M|https://orcid.org/0000-0003-3447-1815', 'Maas|Huub|H|https://orcid.org/0000-0002-2304-2735']
D000328:Adult D000843:Ankle Joint D016022:Case-Control Studies D016000:Cluster Analysis D004576:Electromyography D005684:Gait D006467:Hemophilia A D002836:Hemophilia B D006801:Humans D007592:Joint Diseases D007719:Knee Joint D008297:Male D018482:Muscle, Skeletal D012720:Severity of Illness Index D016138:Walking D055815:Young Adult
neuromuscular control surface electromyography muscle synergy knee joint haemophilia ankle joint