Literature Review: Incremental Shuttle Walk Test (ISWT) Reliability Incremental Shuttle Walk Test (ISWT) has been in use for the last two decades and it is imperative to determine its reliability. Singh, Morgan, Scott, Walters, & Hardman (1992) noted that the ISWT tool could offer an objective means of assessing disability and allowing straightforward comparisons of patients’ activities. A systematic review of the available literature by many scholars shows that the ISWT was regarded as a reliable test for evaluating maximal exercise capacity in people with chronic respiratory conditions. The ISWT was highly responsive in “pulmonary rehabilitation and bronchodilator use in individuals with chronic obstructive pulmonary disease (COPD), cystic fibrosis and asthma” (Parreira et al., 2014, p. 1357). On the same note, de Camargo et al. (2014) also established that the ISWT was “reliable, represented functional capacity and induced greater desaturation than cycling” (p. 892). A study by Jürgensen et al. (2014), test-retest reliability showed results that ranged from good to excellent for the exercise tests with ICC of.90 with a good correlation with the distance covered. The researchers concluded that the ISWT depicted excellent reliability. As a result, they noted that the ISWT was a possible tool for evaluating clinical conditions and intervention effectiveness, particularly in weight loss and rehabilitative strategies (Jürgensen et al., 2014). According to Parreira et al. (2014), evaluation of test-retest reliability of the ISWT showed a value of 0.75, which indicated a good reliability based on test results. The intraclass correlation coefficient (ICC) was used to determine the ISWT reliability because it shows variance estimates from analysis of variance and therefore, highlights relationship and differences between two measures (Parreira et al., 2014). While coefficient of repeatability showed some inconsistencies when used to determine the reliability of various studies, the variation between studies was lower (Bradley, Howard, Wallace, & Elborn, 2000; Fowler, Singh, & Revill, 2005). In this regard, Portney and Watkins note that it is imperative to consider any potential measurement errors within the population of study (as cited in Parreira et al., 2014, p. 1366). The number of tests conducted also has impacts on the reliability of the ISWT. For instance, several researchers, including Singh et al., Morales et al., Booth and Adams, and Pratt, Fairbank, and Virr noted that there were variations between test 1 and test 2, but such changes were not observed in tests 2 and tests 3 in many of the studies reviewed (as cited in Parreira et al., 2014, p. 1366). It is imperative to note that these tests were performed on individuals with COPD apart from one test that involved a patient with advanced case of cancer. In addition, Green et al., Lewis et al., Bradley et al. and da Cunha-Filho et al. among other researchers who conducted two tests only did not show significant variations among patients with COPD (as cited in Parreira et al., 2014, p. 1366). As a result, Parreira et al. (2014) concluded that learning outcomes could have such effects within a given patient population. In other words, the ISWT may be externally paced, but