The side-lying hip abduction exercise is one of the most commonly used exercises in rehabilitation to increase hip abduction strength, and is often performed without external loading. The aim of this study was to compare the effect of 6 weeks of side-lying hip abduction training, with and without external loading, on hip abduction strength in healthy subjects. Thirty-one healthy, physically active men and women were included in a randomised controlled trial and allocated to side-lying hip abduction training, with or without external loading. Training without external loading was performed using only the weight of the leg as resistance, whereas training with external loading was performed with a relative load corresponding to 10 repetition maximum. Hip abduction strength was measured pre- and post-intervention. Isometric and eccentric hip abduction strength of the trained leg increased after hip abduction training with external loading by 12% and 17%, respectively, (P0.05). Six weeks of side-lying hip abduction training, with or without external loading, increases isometric and eccentric hip abduction strength to the same extent.