Aiming at the importance of the detection of physical activity energy expenditure (PAEE), a new system of detecting PAEE based on tri-axial acceleration transducer was presented.

Using three dimensional linear viscoelasticity finite element model, numerical simulation was performed. The deformation of solid propellant grain under axial acceleration was investigated.

Then, through calculating the running speed, a axial travel acceleration model was established, along with the evaluation criteria.