[Specific riding styles are associated with specific effects on bodily posture control].

Abstract: The assessment of body posture control can be time consuming and cumbersome due to the complexity and the multimodal influence of a multiply influenced system. Various types of equine paces, such as stepping, trotting or galloping, result in acceleration and deceleration forces of different magnitude. These forces induce, in the horseman, reflexes that mediate motor activity to sustain posture balance and counterbalance the gravitational pull. However, there is a paucity of real life data regarding the extent of the various postural subsystems that are recruited to control postural balance in specific equine disciplines, such as classical dressage, show jumping, or vaulting. This study was conducted to bridge that gap. Objective: The aim of this explorative study was to identify the types of the postural subsystems involved in balance control and assess the magnitude of their activities during classical dressage, show jumping, vaulting, and versatility riding. Methods: 144 horseback riders (8.1 % males) aged 17.3 +/- 2.9 years and 38 age matched controls (non riders) were investigated. The riders studied were competing in dressage, show jumping, vaulting, and versatility. In each individual, postural control was investigated by means of the "interactive balance system (IBS)" that enabled us to determine the spectral power in the following four standard frequency bands: F 1 (0.03 - 0.1 Hz), F 2 - 4 (0.1 - 0.5 Hz), F 5 - 6 (0.5 - 1.0 Hz), and F 7 - 8 (1.0 - 3.0 Hz). In addition, three motorical output indices were calculated: heel-to-toe-ratio (HTR), synchronization of feet (SYNC), and the global stability index of postural balance (STAB). Furthermore, each individual was interviewed regarding riding time, frequency and discipline and also about other sports activities and disorders of health. Results: The mean training period of the horseback riders was 122 +/- 45.8 months, and mean weekly frequency of training was 5.5 +/- 1.8 days per week. Balance control was most effective in dressage and vaulting riders and least effective in show jumping competitors: HTR was 51 +/- 8 % (dressage), 48 +/- 8 % (show jumping), 47 +/- 8 % (versatility), 51 +/- 7 % (vaulting); SYNC was 523 +/- 124a. i. (dressage), 497 +/- 156a. i. (show jumping), 468 +/- 155a. i. (versatility), 589 +/- 126a. i. (vaulting). Spectral analysis revealed significantly higher power in F 1, F 2 - 4, and F 7 - 8 in dressage competition than in the other equestrian disciplines but not compared with the controls. Significantly differences between riders versus non riders were only found in HTR (p = 0.045) und SYNC (p = 0.009). Conclusions: Balance control was most effective in dressage and vaulting riders and least effective in the show jumping competitors. Thus, except for dressage and vaulting, our results do not suggest a positive effect of traditional riding styles on postural stability and control.