Physical activities are associated with increased production of reactive oxygen species. The production of reactive oxygen species is dependent of the intensity, duration and type of activity. Although the physiological amounts of reactive oxygen species are necessary to regulate cell reactions, their excessive production can cause numerous damages to the structure and function of cells and weaken physical function and endanger health. Although physical activity itself is a stimulus to increase the capacity of antioxidant defense, but in the case of intense and long exercises, the production of reactive oxygen species exceeds the capacity of antioxidant defense. In this situation, the use of exogenous antioxidant substances can be a good solution for the development of performance and physical health. Plants are abundant sources of antioxidant substances that can neutralize most active oxygen species caused by physical exercises, and then reduce inflammation and muscle damage induced by repeated muscle contractions, especially extrinsic contractions. Despite controversial findings due to differences in the methodologies of studies, their results generally confirm the effects of phytochemicals on reducing oxidative stress, inflammation, pain, muscle damage and improving physical performance. Based on these findings, it is recommended that people who undertake intense and long physical exercises should use plants containing phytochemicals in order to maintain and improve physical performance and develop health.