(Neiman 2010) defined Mental fatigue as psychobiological state caused by prolonged periods of demanding cognitive activity. A lack of energy and tiredness is usually associated with mental fatigue. Mental load is the work we do mentally in order to manage our life. In psychology, cognitive load is often described as the total amount of mental effort being used in the working memory. Some individuals may carry mental load in real life situations for example going to work and personal life. In science research when individuals perform a mental loading exercise prior to an extreme exercise or a difficult test, they exhaust more rapidly than when they did the same exercise when mentally rested. Moreover, mental fatigue does not cause our cardiovascular system to perform differently; instead, our “perceived effort” usually determine when we get tired. In psychology researchers are trying to investigate why people with mental fatigue perceive exercise to be more difficult. Research has shown that mental fatigue effects mental and physical performances in certain situations. (Marcora, Staiano and Manning, 2009) investigated that mental fatigue decreases exercise tolerance in humans through higher perception of effort rather than cardiorespiratory mechanisms. Scientific research has shown that the most important factor responsible for the negative impact of mental fatigue on endurance performance is a higher perceived exertion. Many other contributing factors such as the decrease in physical tasks may affect physical performance. Although the impact of mental fatigue on cognitive and skilled performance is well known, its effect on physical performance has not been thoroughly investigated The aim for this study is to investigate if mental load during training improves mental and physical performance, for this study our null hypothesis is that there will be an effect on mental and physical performance during training and the alternative hypothesis is that there will be no effect on mental and physical performance during training.