The factors that limit human endurance have received extensive scientific scrutiny. Traditionally these limiting factors have been attributed to physiological processes occurring within the muscles, the cardiovascular system, or spinal and supraspinal sites. Consequently, interventions designed to provoke alterations in endurance performance are generally tailored towards targeting these physiological processes. Recent research suggests that endurance performance is also limited by psychobiological influences: specifically perception of effort (RPE). On this basis the psychobiological model of endurance performance predicts that any physiological or psychological factor affecting RPE will alter endurance performance. As such, this thesis sought to elicit alterations in RPE, and consequently physical endurance, using psychobiological strategies that were implemented to directly target RPE. In Chapter 2 it was established that a two week motivational self-talk intervention significantly reduced RPE at 50% iso-time while enhancing cycling time to exhaustion (TTE) by 18%. This equated to a very likely beneficial practical effect on TTE (beneficial/trivial/harmful%; 99/1/0%). In Chapter 3, a six week cognitive training protocol was designed to repeatedly target the anterior cingulate cortex due to its neuro-cognitive connections with cognitive and physical effort. This approach did not significantly alter RPE or TTE at exercise intensities of 80% or 65% peak power output (PPO). A likely beneficial practical effect on TTE was nonetheless evident at 65% PPO (83/15/2%). Using subliminal affective priming in Chapter 4, RPE was significantly lower and TTE significantly greater when participants were subliminally primed with happy faces while cycling compared to an alternative visit when they were subliminally primed with sad faces. This difference in TTE was of possible practical value (70/30/0%). Following on from this, Chapter 5 implemented a single subject approach using a randomization tests design and illustrated that subliminally primed action words significantly reduced RPE and enhanced TTE compared to subliminally primed inaction words.