The hypotheses of this research are that individually tailored worksite-based intelligent physical exercise training , IPET , among workers with inactive job categories will : 1 ) Improve cardiorespiratory fitness and/or individual health risk indicators , 2 ) Improve muscle strength and decrease musculoskeletal disorders , 3 ) Succeed in regular adherence to worksite and leisure physical activity training , and 3 ) Reduce sickness absence and productivity losses ( presenteeism ) in office workers .