During physical activity, hemoglobin-bound oxygen is supplied to the exercising muscles through arteries, arterioles and capillaries, whereas venous return carries deoxygenated hemoglobin to the lungs for re-oxygenation. Oxygen metabolism in muscles (supply, consumption and release of metabolism byproducts) occurs at cellular level. However, muscle oxygenation is also observable at organ (muscle) level by investigating the quantity of oxyhemoglobin and deoxyhemoglobin in the capillary network available as a new source of oxygen and as a result metabolic processes, respectively. Oxygen metabolism is affected by physical activity both in the short-term (at the level of individual muscle contraction) and long-term (duration and strength of exercise). In the short-term, the mechanical contraction of muscular fibers causes the occlusion of arterial vessels and capillaries, therefore the blood (and oxygen) supply decreases, and normal blood flow is re-established during muscle relaxation. In the long-term, exercise activity consisting of continuous muscle contractions-relaxations at a steady-state or increasing workload causes a decrease of oxygenation which is greater that the decrease observable in a single muscle contraction. In our previous invention, we disclosed a method that allows to establish a training threshold of an exercising individual derived from muscle oxygenation measured by near-infrared spectroscopy (NIRS). In this disclosure, we disclose a method that measures physiological parameters related to physical activity, such as exercise cadence (e.g., jogging/running pace, pedaling cadence, weightlifting cadence, etc.) and estimates energy expenditure. Such measures can be extracted by raw or processed NIRS readings.