You have captured the posture well but it doesn't really flow. Maybe you can use longer lines and also look more at the shape of the body parts (for example the legs usually have this little bulge of muscle at one side and a more or less straight line at the front).
Something that helped me a lot with gesture drawings was drawing the most prominent lines and not desperately trying to close a shape. This is good practise to find the flow of a posture. Hope it helps :)
