This study aimed to evaluate the use of Pessoa's rein in training equine, as a support in exercise training, on biometry by ultrasonography of the epaxial (Longíssimus Dorsi, Gluteus Medius e Musculus Multifidus) and pelvic musculature (Biceps Femoris e Semitendinosus). Thereby, eight Quarter Horse mares was used, with eight years on average age, 400kg of body weight, trained with the Pessoa's rein twice a week, for two months. Variables were measured before and after training, consisting of assessment thickness (cm) of the Longíssimus Dorsi and cross-sectional area (cm2) of muscles, Gluteus Medius, Biceps Femoris, Semitendinosus and Musculus Multifidus. It observed a significant effect of training with Pessoa's rein, on the Biceps Femoris (P<0.01) and Musculus Multifidus (P<0.01), which the average cross-sectional area at the final evaluation were of 28.66cm2 and 14.29cm2, respectively. Thus it can be conclude that training with Pessoa's rein modifies muscular function, promoting hypertrophy Musculus Multifidus and Biceps Femoris of horses
aid rein; Biceps Femoris; Gluteus Medius; horse Longíssimus Dorsi; Musculus Multifidus; semitendinousus
