Trunk and Lower Extremity Muscle Activation in Children in Various Seated Positions on Horseback

Research Objectives To investigate muscle activation of trunk and lower extremity muscles in children in six positions on horseback commonly used by therapists during hippotherapy sessions. Design Comparison of muscle activation levels within and between six different riding positions. Setting Data collection took place in the general community at a local equestrian facility. Participants Convenience sample of fifteen healthy children aged between 4 and 12 years old with no previous horseback riding experience. Interventions Surface EMG readings were collected for eight trunk and lower extremity muscles while children were seated in six positions on horseback. Positions were: facing forward, backwards, and sitting sideways on the horse. Upper extremity positions were also manipulated for each seated position and included: hands resting in laps vs. arms abducted to 90°. Main Outcome Measures Mean amplitudes of the EMG data for each muscle in each position were normalized by converting to a percentage of average activity of the same muscles during a walking trial of each subject. The resulting percent muscle activity was compared across subjects and positions. Results Higher levels of activation for the erector spinae were found for forward arms abducted (FAA) compared to forward hands in lap (FHL) (p= 0.001), sideways arms abducted (SAA) compared to FHL (p= 0.006), and SAA compared to sideways hands in lap (SHL) (p= 0.005). Rectus abdominis demonstrated higher activation with SHL as compared to FHL (p= 0.005), SAA (p= 0.001), and FAA (p= 0.005). Significant differences for gluteus medius activity were found in comparing SHL and SAA to FHL (p= .023 and .027). Conclusions Different positions on horseback result in changes in muscle activation of the rider. For therapists wanting to encourage activation of the erector spinae in clients during hippotherapy sessions, all positions with arms abducted resulted in higher activation levels. If activation of the rectus abdominis or gluteus medius is desired, clients may benefit most from a sideways position vs. sitting forwards or backwards. Author(s) Disclosures I declare no conflicts of interest.