The aim of the study is to measure the effectiveness of treatment over 7 days with commonly used anti-inflammatory medications namely etoricoxib and diclofenac (Voltaren) on reducing the severity of pain, swelling and loss of function (range of movement, proprioception) arising from a mild to moderate sprain (partial tear) of the lateral (outer) ligaments of the ankle joint. This injury is commonly known as an ankle sprain.