Incremental shuttle walk test: Reference values and predictive equation for healthy Indian adults

Abstract

Purpose:Physical inactivity in Indians is leading to an increase in noncommunicable disorders at an early age in life. Early identification and quantification of the lack of physical activity using simple and reliable exercise testing is the need of the hour. The incremental shuttle walk test (ISWT) is an externally paced walk test widely used for the evaluation of exercise capacity. Currently the normative values available for clinical reference are generated from Western populations. Hence, the study was conducted to find normative values for the ISWT in healthy Indian adults (17-75 years).Materials and Methods:A convenience sample of 862 subjects was recruited after ethical approval was obtained. All subjects were divided into groups as per age and gender. For age, the grouping was as follows: Group 1: Young adulthood (17-40 years), group 2: Middle adulthood (40-65 years), and group 3: Old adulthood (>65 years). The ISWT was performed as per standard protocol by Sally Singh.Results:The average distance walked were 709.2m,556.4m and 441.3m in females and 807.9 m, 639.6 m and 478.2 m in males in the three respective age groups. Stepwise regression analysis revealed age and gender as key variables correlating with incremental shuttle walk distance (ISWD). The derived predictive equations for males and females may be given as follows: 740.351 - (5.676 × age) + (99.007 × gender).Conclusion:Reference values were generated for healthy Indian adults. Physiological response to the ISWT was shown to be affected by gender and increasing age. Easily measurable variables explained 68% of the variance seen in the test, making the reference equation a relevant part of the evaluation of the ISWT.

The influence of South Asian ethnicity on the incremental shuttle walk test in UK adults

“…It is unknown how %HR max values compared against UK participants from the study by Harrson et al 6 as this was not reported. However, %HR max levels of the present study were similar to those observed in South American 7 and Indian 8 populations. Additionally, with 84% of South Asians achieving a greater distance on the second test (66% for Caucasian British), further improvement may have occurred with a third ISWT, a notion also highlighted by Probst et al 25 Given not all participants had English as their first language, the additional challenges of instructing and motivating participants may have contributed to the lower %HR max values.…”

“…Despite this, only 50% (South Asian) and 58% (Caucasian British) of the variance was explained by these variables in the reference equation models. The prediction equations of Probst et al 25 and Agarwal et al 8 accounted for a greater proportion of the variance (71% and 68%, respectively) than those of the present study and Harrison et al 6 (50.4%) despite only incorporating age and gender 8 and BMI 25 into the multivariate models. The use of the modified ISWT by Probst et al, 25 which adds three more levels (420 m) to the original ISWT, 3 may have eliminated the ceiling effect observed for participants who completed the test.…”

“…Distances covered during the ISWT in the present UK sample were lower than that of other findings. 6 , 8 For both ethnic groups, greater coaching may have facilitated better performances, particularly for apparently healthy individuals who may not perceive a walking-based test to be maximal. Currently, the ISWT pre-recorded instructions are only available in English, so translators may be required to adequately explain the test to individuals who do not have English as their first language.…”

“…To date, normative values for the ISWT have been provided on three continents: South America 7 ; Europe 6 and Asia. 8 Normative values are of great importance because they describe the natural history of clinical outcomes or conditions and help develop standards of care. 9 With societies around the world becoming increasingly ethnically diverse, a need to investigate differing populations has been advocated.…”

Reliability and validity of an audio signal modified shuttle walk test

“…It is an inexpensive tool and has been used to assess exercise capacity in the pulmonary rehabilitation setting for patients with COPD[ 3 4 5 6 7 ] as well as for patients with other diseases. [ 8 ]…”