New approaches and more powerful techniques to measure dynamic variability during gait are needed to better assist older people in fall prevention, as well as in the diagnosis and rehabilitation of populations that suffer a neuromuscular impairment or disease. In this thesis a novel approach is presented that combines two existing techniques to measure dynamic variability during walking. This approach uses dynamic variability as a measure to quantify the dynamic stability of walking in two different situations. The first situation is when walking with different type of footwear;​ the second situation is walking in a dual task situation, specifically, walking while performing cognitive tasks of increasing levels of difficulty.

The results showed that the new approach was sensitive enough to detect changes in the dynamic stability of walking among different footwear conditions and to detect changes in the dynamic stability when walking under dual task conditions of different levels of difficulty. In the first case, the special shoe (considered unstable) showed significantly less dynamic during walking compared to regular shoes and barefoot condition. In the second case, dynamic stability increased when performing a secondary cognitive task. Furthermore, this approach also demonstrated differences among old and young groups. The approach introduced in the current work allows a quantitative assessment of the dynamic stability of the whole body main walking patterns and might be useful for clinical and/or sport applications.