"Exercise is much harder for me than for others, for example, and I don't know why." genetics can partially account for the lack of improvement after training,

"Exercise is much harder for me than for others, for example, and I don't know why." genetics can partially account for the lack of improvement after training, one specific gene "alpha-actinin 3 (speed gene)". The other component is environment. Why is it that some people respond better to training than others? Are you a sprinter or a marathon runner? http://www.abc.net.au/catalyst/stories/4132778.htm http://www.abc.net.au/catalyst/stories/4132778.htm