Prisoners should not spend all day locked in a cell or dormitory or sitting in a yard. They should be kept occupied. Providing a full range of constructive activities for prisoners plays an important part in what was described in chapter 15 of this Manual as the "dynamic security" of the prison. This means that, if prisoners are fully and productively engaged in constructive activities, the prison is likely to be safer and more secure. The activities in which prisoners are involved should have a purpose and should equip them with skills which they can use after their release from prison. Prisoners should also be given opportunities for personal development. These opportunities should deal with personal, emotional, religious and cultural needs. All of these taken together are sometimes referred to as "rehabilitation". Prisoners should also be prepared to live a crime-free and useful life after they are released. PRACTICAL RECOMMENDATIONS ■ The European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment suggests that long-term imprisonment can have a number of desocializing effects on inmates. Long-term prisoners become institutionalized, experience a range of psychological problems and have a tendency to become detached from society to which almost all of them will return. The Committee recommends that the prisoners concerned should have access to a wide range of purposeful activities of a varied nature (work, preferably with vocational value; education; sport; etc.) and that prisoners should be able to exercise a degree of choice over the manner in which their time is spent, thus fostering a sense of autonomy and personal responsibility. 98