 The sample size calculation is based on the following finding and expectation. The improvement in ISS primary outcome over one year for the standard physical therapy group was 50 Oerlemans, APMR 2000, for the PEPT group it is estimated at minimal 70-80. Given an alpha of 0,05 and a power of 80 for a one sided Chi-square test 31 patients are needed per group. The Student T- test is used to calculate differences between both groups in mean ISS. 