OBJECTIVE: Analyse possible differences in muscle activation in different posture and exercises on the horse in a case of a girl with spina bifida (D12-L1) versus a girl with neurotypical development.
METHODOLOGY: Subjects: The study was carried out in two 7-year-ol girls, (1) a girl with a diagnosis of spina bifida (D12-L1) and (2) a girl with neurotypical development.
Procedure: The muscle activity of the multifidus and lower rectus abdominis muscle has been analyzed billaterally by surface electromyography. For this, several postures and exercises have been performed on the horse: (1) Sitting astride the standing horse, (2) arms extended foward, (3) stops and starts, (4) greater amplitude of the horse ́s steps. Subsequently, a qualitative analysis of the results has been carried out. The instrument used was surface EMG equipment (Shimmer®, mDurance Pro®) and the electrodes were placed following the SENIAM protocol.
RESULTS: (1) In the straddle sitting position, the concept of neuromuscular efficency is evidenced, observing that in the case of neutral development, muscle activation to maintain a static posture is less than when there is a neurological injury, which implies the need for greater muscle activation, to maintain posture. (2) The forward arm exercise implies a greater activation of the abdominal muscles, a fact that is observed when there is no neurological alteration, however, in the girl with spina bifida for the maintance of the position it recruits more the posterior muscles. (3) In stops and starts and walking, in both cases muscle activation is manifested, but when there is no neurological injury, the muscle recruitment pattern is more homogeneous versus a more heterogeneous behaivor of the curve in the case of the girl with spina bifida.
(4) The greater amplitude of the horse ́s gait, the greater the muscle activation of the anterior and posterior chains is required, manifested when there is no neurological injury but in the case of spina bifida, greater asymmetry is observed, that is, for posture maintenance. Some muscles are activated more in compensation for those with less activation.
CONCLUSION: Surface electromyography allows determing differences in muscle activation between a case of a girl with spina bifida versus a girl with neurotypical development, which is why it can be a useful resource to assess and guide therapeutic interventions in hippotherapy, being
advisable to complement the valuation with other instruments that allow the analysis of the movement.