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The need to attend a medically supervised hospital- or clinic-based appointment is a well-recognized barrier to exercise participation. The development of reliable and accurate home-based functional tests has the potential to decrease the burden on the health care system while enabling support, information, and assessment.
This study aims to explore the usability (ie, acceptability, satisfaction, accuracy, and practicality) of the EasyMeasure app to self-administer the 6-minute walk test (6MWT) in young, healthy adults and determine parallel form reliability and construct validity of conducting a self-administered 6MWT using technology.
We used a usability study design. English-speaking, undergraduate university students who had access to an iPhone or iPad device running iOS 10 or later and self-reported ability to walk for 6 minutes were recruited for this study. Consenting participants were randomized to either a standard 6MWT group (ie, supervised without the use of the app) or a technology 6MWT group (ie, unsupervised with the app to mimic independent implementation of the test). All participants performed a maximal treadmill test. Participants in the 6MWT group completed the Unified Theory of Acceptance and Use of Technology (UTAUT) questionnaire and a satisfaction questionnaire after completing the assessment. Parallel form reliability of the 6MWT using technology was analyzed by comparing participant self-administered scores and assessor scores using Pearson correlation coefficients across and between trials. Construct validity was assessed by comparing participant 6MWT scores (both standard and using technology) with maximum treadmill test variables (peak oxygen uptake and ventilatory threshold [VT]).
In total, 20 university students consented to participate in the study. All but 2 participants (8/10, 80%) in the technology 6MWT group had deviations that prevented them from accurately conducting the 6MWT using the app, and none of the participants were able to successfully score the 6MWT. However, a significantly strong correlation was found (
This study demonstrated significant usability concerns regarding the accuracy of a self-administered 6MWT using the EasyMeasure app. However, the strong and significant correlation between the 6MWT and VT values demonstrates the potential of the 6MWT to measure functional capacity for community-based exercise screening and patient monitoring.
Tests of mobility, physical functioning, and aerobic capacity are commonly used in research and clinical practice to evaluate the impact of exercise programs [
In Canada, there is a rapidly growing aging population wherein 1 in 4 adults live with 2 or more chronic conditions, and half of older adults live with three or more chronic conditions [
The 6-minute walk test (6MWT) is an easy to perform, submaximal, and widely used test of functional exercise capacity [
The EasyMeasure app [
The primary objective of this study is to explore the usability (ie, acceptability, satisfaction, accuracy, and practicality) of the EasyMeasure app to self-administer the 6MWT in young, healthy adults. Our secondary objectives are to determine the parallel form reliability and construct validity of conducting a self-administered 6MWT using technology. The results of this trial in a healthy young adult population will help determine the updates and changes necessary for successful implementation before use with other populations.
A usability study design was used to test the app characteristics, parallel form reliability, and construct validity of conducting a self-administered 6MWT using technology in a controlled setting. Participants were asked to perform either a self-administered 6MWT using the EasyMeasure app or a traditional investigator-supervised 6MWT in the laboratory. All participants were also asked to perform a maximal treadmill test for aerobic capacity. The University of Toronto Research Ethics Board approved this study (#37108).
We recruited 20 undergraduate university students via email within the Faculty of Kinesiology and Physical Education and among varsity athletes from the University of Toronto. Eligible participants included (1) English-speaking (2) undergraduate university students (3) younger than 30 years (4) who had access to an iPhone or iPad device running iOS 10 or later, (5) were willing to download the EasyMeasure app on their device, and (7) self-reported being able to walk for 6 minutes. Potential participants were excluded from the study if they (1) self-reported having any physical injury or condition that precluded them from walking safely for 6 minutes or (2) self-reported a cognitive condition that precluded them from understanding instructions or the consent form provided. Interested respondents contacted the study investigators to schedule an assessment session date and time. All participants were required to complete written informed consent before beginning the project.
Eligible consenting participants were randomized to either the standard 6MWT group (ie, supervised without the app) or the technology 6MWT group (ie, unsupervised with the EasyMeasure app to mimic independent implementation of the test). Before the testing session, all participants were asked to download the EasyMeasure app onto their devices. Upon arrival at the testing sessions, participants were informed of which version of the 6MWT they would complete. Participants’ heart rate, blood pressure, rate of perceived exertion (RPE), and oxygen saturation levels were assessed before and after the testing sessions to ensure participant safety.
Participants in the standard group were given the 6MWT instructions by an assessor (physiotherapist [JST] or exercise physiologist [SCA]). Participants were asked to walk as quickly as possible in a comfortable manner for 6 minutes along a previously measured straight pathway. During the test, participants were timed by the assessor and given standard encouragement at each minute interval. The assessor counted the number of laps performed by each participant. At 6 minutes, participants stopped at their location along the path, and the assessor measured the total distance walked for the final lap. The assessor calculated the total distance walked in 6 minutes and interpreted the participants’ test scores.
Compared with the standard 6MWT group, participants in the technology group had to measure the distance between objectives (measure the test path), time the test, and count laps independently. To accomplish this, participants in the technology group were given instructions by the assessor on how to use the EasyMeasure app (including instructions for proper calibration of the app as well as how to measure the distance to an object and how to take a photo of the distance recorded), how to perform the 6MWT, and how to interpret their 6MWT scores. Participants used the app to measure the distance from the starting point to a predefined object. They recorded the distance between the starting point and the object by taking a still image using the app. Participants then walked consistently for 6 minutes around the 2 objects. Independent of the EasyMeasure app, they timed themselves using their cell phones and counted laps (either within their head or with the counter function on their phone). At the completion of the 6 minutes, they used the EasyMeausre app to measure the distance walked along the path during their final lap. They recorded this distance by taking a still image using the app. After performing the test, participants calculated the results of their test (ie, how many meters they walked in 6 minutes) by multiplying the number of laps walked by the distance measured in the app. They then interpreted their test scores by comparing their 6MWT score with provided normative values for age and sex (ie, determine if their scores were within normal limits for their age range and state if they were safe to exercise independently based on results).
This test was performed autonomously but in the laboratory. An assessor was present but did not interfere with or provide encouragement. The assessor knew the distance from the starting line to the object of measurement and counted the laps the participants completed to track accuracy; however, participants were not aware of the assessor’s count. The assessor also made notes on the number of deviations to instructions made by participants, the ability of participants to successfully report and interpret their scores, and if any additional resources were needed by participants.
After completing the test, participants in this group completed the Unified Theory of Acceptance and Use of Technology (UTAUT) questionnaire and a satisfaction questionnaire. The UTAUT is an 18-item self-report measure used to explain individuals’ intentions to use a form of technology. It holds four key constructs, including (1) performance expectancy (the extent to which the individual believes that use of the technology will lead to improved health), (2) effort expectancy (how easy was the use of technology perceived to be), (3) social influence (the extent to which an individual believes that others want them to use this technology system), and (4) facilitating conditions (to what extent did an individual believe there is the organizational and technical infrastructure to support the use of this process) [
Following the 6MWTs, VO2peak was assessed via a CPET on a treadmill under the supervision of a certified exercise physiologist (SCA) using an individualized protocol [
The sample size for this study was determined based on informal guidelines for usability (ie, acceptability, satisfaction, accuracy, and practicality), suggesting a group size of 3-20 participants [
Quantitative data were summarized using descriptive statistics (ie, means and SDs reported for continuous data; frequencies and percentages reported for categorical data). The open-ended survey questions were analyzed using qualitative descriptive analysis, and responses were grouped into meaningful categories that arose from the data. Parallel form reliability of the 6MWT using technology was analyzed by comparing participant self-administered scores with assessor scores using Pearson correlation coefficients across and between trials. A
In total, 20 university students consented to participate in this study; 10 participants were randomized to each group. Most participants (16/20, 80%) were female with a mean age of 20.1 (SD 2.2) years. Participants had a mean height of 165.8 (SD 7.8) cm and a mean weight of 65.0 (SD 10.9) kg. Participant characteristics and VO2peak estimates for each group are shown in
Participant characteristics and 6MWTa results.
Characteristic | Standard 6MWT group (n=10) | 6MWT using technology (n=10) |
Age (years), mean (SD) | 20.6 (2.91) | 19.5 (1.18) |
Sex (female), n (%) | 8 (80) | 8 (80) |
Height (cm), mean (SD) | 168.22 (6.87) | 163.44 (8.22) |
Weight (kg), mean (SD) | 65.55 (11.17) | 65.52 (11.36) |
6MWT distance (m), mean (SD) | 658.74 (62.69) | 495.30 (80.95)b |
VO2peakc estimate 1d, mean (SD) | 23.74 (1.88) | 19.56 (4.75) |
VO2peak estimate 2e, mean (SD) | 24.45 (1.62) | 21.41 (3.78) |
VO2peak estimate 3f, mean (SD) | 20.10 (1.44) | 16.90 (3.64) |
a6MWT: 6-minute walk test.
bAssessor score.
cVO2peak: peak oxygen uptake.
dPeak oxygen uptake = 0.03 × distance (m) + 3.98 [
ePeak oxygen uptake = 0.02 × distance (m) − 0.191 × age (years) − 0.07 × weight (kg) + 0.09 × height (cm) + 0.26 × (rate pressure product × 10−3) + 2.45 [
fPeak oxygen uptake = 4.948 + 0.023 × distance (m) [
A total of 10 participants completed the 6MWT using this technology. All but 2 participants (8/10, 80%) had deviations that prevented them from accurately conducting the test using the EasyMeasure app. This included 60% (6/10) of participants who lost the count of laps, 40% (4/10) who did not walk at their maximum pace, and 10% (1/10) who did not measure the distance of their last lap.
None of the participants were able to successfully score (ie, calculate the actual distance covered in 6 minutes) the 6MWT; 60% (6/10) of participants did not count the number of laps correctly, and 60% (6/10) measured the distance of each lap incorrectly by ≥0.5 m. In total, 30% (3/10) of participants interpreted their scores incorrectly, reporting that they were within normal limits for their age and sex when they were not; 40% (4/10) of participants identified that they required additional resources to conduct the test successfully, with 20% (2/10) of participants suggesting the need for a lap counter and a calculator.
Unified Theory of Acceptance and Use of Technology results.
Question | 1 (strongly disagree), n (%) | 2 (disagree), n (%) | 3 (neither disagree or agree), n (%) | 4 (agree), n (%) | 5 (strongly agree), n (%) | Mean score (SD) | ||
|
10.3 (1.25) | |||||||
|
PE1 | 0 (0) | 1 (10) | 6 (60) | 3 (30) | 0 (0) | 3.2 (0.63) | |
|
PE2 | 0 (0) | 0 (0) | 2 (20) | 7 (70) | 1 (10) | 3.9 (0.57) | |
|
PE3 | 0 (0) | 1 (10) | 6 (60) | 3 (30) | 0 (0) | 3.2 (0.63) | |
|
12.8 (1.75) | |||||||
|
EE1 | 0 (0) | 0 (0) | 1 (10) | 6 (60) | 3 (30) | 4.2 (0.63) | |
|
EE2 | 0 (0) | 0 (0) | 1 (10) | 4 (40) | 5 (50) | 4.4 (0.70) | |
|
EE3 | 0 (0) | 0 (0) | 1 (10) | 6 (60) | 3 (30) | 4.2 (0.63) | |
|
9.60 (2.01) | |||||||
|
SI1 | 1 (10) | 3 (30) | 5 (50) | 1 (10) | 0 (0) | 2.6 (0.84) | |
|
SI2 | 0 (0) | 0 (0) | 4 (40) | 5 (50) | 1 (10) | 3.7 (0.67) | |
|
SI3 | 1 (10) | 2 (20) | 2 (20) | 3 (30) | 2 (20) | 3.3 (1.34) | |
|
18.9 (2.60) | |||||||
|
FC1 | 0 (0) | 0 (0) | 1 (10) | 1 (10) | 8 (80) | 4.7 (0.67) | |
|
FC2 | 0 (0) | 0 (0) | 1 (10) | 1 (10) | 8 (80) | 4.8 (0.79) | |
|
FC3 | 0 (0) | 0 (0) | 1 (10) | 0 (0) | 9 (90) | 4.8 (0.63) | |
|
FC4 | 0 (0) | 1 (10) | 0 (0) | 1 (10) | 8 (80) | 4.6 (0.97) | |
|
4.3 (1.15) | |||||||
|
ANX1 | 7 (70) | 3 (30) | 0 (0) | 0 (0) | 0 (0) | 1.3 (0.48) | |
|
ANX2 | 4 (40) | 5 (50) | 1 (10) | 0 (0) | 0 (0) | 1.56 (0.70) | |
|
ANX3 | 5 (50) | 4 (40) | 1 (10) | 0 (0) | 0 (0) | 1.6 (0.70) | |
|
5.9 (2.33) | |||||||
|
B2 | 2 (20) | 3 (30) | 2 (20) | 2 (20) | 1 (10) | 2.7 (1.33) | |
|
B3 | 1 (10) | 2 (20) | 1 (10) | 6 (60) | 0 (0) | 3.2 (1.14) |
aPE: performance expectancy.
bEE: effort expectancy.
cSI: social influence.
dFC: facilitating conditions.
eANX: technology anxiety.
fPerformance expectancy, effort expectancy, social influence, facilitating conditions, behavioral intention to use scales: a higher score is better (eg, higher performance expectancy); for the technology anxiety scale, a lower score is better (lower anxiety).
gB: behavioral intention to use.
Satisfaction questionnaire results.
Question | Median scorea |
1. How logical does the use of the EasyMeasure app to conduct a self-administered 6MWTb seem to you? | 5.5 |
2. How scientific does this way of testing the 6MWT seem to you? | 5 |
3. How complete does this way of testing the 6MWT seem to you? In other words, do you think this method covers all of the necessary steps of performing this test to get an accurate value? Would you need any other resources? | 5 |
4. To what extent would this form of self-evaluation help an individual assess their performance capacity? | 5 |
5. How likely would you be to use this method to assess your 6MWT score if it was available to you? | 4.5 |
6. How likely would you be to assess your 6MWT score in this capacity at home, compared to having a certified health care professional perform this test for you at another location? | 5.5 |
7. How effective do you think this method to assess a 6MWT score would be for most people? | 4 |
8. If a close friend or relative wanted to assess their walking capacity, would you recommend they use this method to test? | 5 |
aScored from 1 (not at all) to 7 (extremely).
b6MWT: 6-minute walk test.
A significantly strong correlation was found (
Participant versus assessor scores using 6-minute walk test technology.
After reviewing the outcomes on a scatterplot, two participant scores were removed as outliers. The remaining scores demonstrated no significant correlation between maximal treadmill test VO2peak scores and any of the 6MWT prediction equations using the standard 6MWT scores (equation 1:
Owing to inaccuracy in participant scores when performing the self-administered 6MWT using technology, comparisons were only made between assessor scores and maximal treadmill test VO2peak scores. After reviewing the scores on a scatterplot, no outliers were removed. A significant correlation was found between equation 2 and the 6MWT scores (equation 2:
After observing the participants in the 6MWT group, the assessor noted commonalities in participant behavior. First, many young adults in this group were not perceived to be walking at their maximum speed, as instructed by the assessor. It appeared to be difficult for this group to multitask (walk, count laps, and time themselves) and correctly interpret their 6MWT scores. For example, even when scores obtained were below normal age-matched values (most often due to not walking at maximum walking speed), they often said they were
The usability, reliability, and validity of conducting a self-administered 6MWT using a distance measurement app was explored among healthy young adults. The results of this study suggest that participants accepted the EasyMeasure app to perform the 6MWT. However, a primary finding of this study is that participants were unable to accurately self-administer and interpret the results of the 6MWT using this app. This finding suggests that the autonomously implemented 6MWT may not be feasible. Overall, these findings suggest a need to update the app and develop a more accurate process for measuring and interpreting the 6MWT before it can be used for clinical and research purposes. Our findings are particularly concerning given that younger university students are adept at using technology and applying simple standards for interpreting their results compared with older individuals living with or without chronic comorbidities [
Interestingly, our findings of inaccuracy are not consistent with those from a related study that tested an investigator-developed 6MWT app in older patients with chronic heart failure and hypertension [
The parallel form reliability findings revealed a significantly strong correlation between participants’ self-administered 6MWT scores and assessor scores for the group using technology. However, the differences between participant and assessor scores all exceeded the MCID values for the 6MWT (ie, 19-49 m [
Finally, validity results from this project found that 6MWT scores were significantly and strongly correlated with maximal treadmill test VT scores. This finding demonstrates that the 6MWT may be a valid measure of functional capacity and a marker of functional independence for clinicians to use when screening and monitoring patients in community settings. However, the results of this study showed that the 6MWT scores did not correlate with the maximal treadmill test VO2peak scores. In this study, the 6MWT consistently underestimated VO2peak. There is variability in the literature regarding this outcome, with some studies demonstrating the validity of the 6MWT in predicting VO2peak [
On the basis of the findings of this study, it is recommended that the app used to self-administer the 6MWT be redesigned. Future apps should include functions that count laps, measure total distance walked, and time the test for users. This would help to overcome participant errors demonstrated in this study because of difficulty counting test laps and miscalculation of the total distance walked. In addition, several modifications to our tested methods should be considered to help overcome the usability issues identified in this study. The primary recommendation is to provide more detailed information and education to participants regarding the methods needed to accurately perform the test. This should include training videos or written instructions in addition to verbal instructions on how to calibrate the app to accurately measure the distance walked and information on how to perform and score the test. This would allow participants to review instructions before beginning the test, which may be most important if the test is being used with older adults or individuals who report a lack of competence with new technologies [
The results of this study should be viewed with an understanding of their limitations. Testing of the self-administered 6MWT, which was designed to mimic a home-based test, took place in a laboratory setting. Although these tests were implemented in a room that was roughly the size of a large living room, we recognize that this does not reflect the space available to many people and suggest adding a third home-based arm in future studies. Adding a third home-based arm would be ideal because it would allow researchers to differentiate between issues resulting from measurement tools and measurement settings. In addition, the small sample size was determined based on usability study recommendations, and a larger sample with more diverse characteristics should be used for future testing and power considerations. A limitation of the 6MWT is evidence of a ceiling effect [
In conclusion, this study demonstrated significant usability concerns regarding the accuracy of a self-administered 6MWT using the EasyMeasure app. Despite the reported ease of use of this technology, the inaccurate measurements and challenges associated with interpreting the test scores suggest that the app design and tested protocol are of limited use for research and clinical purposes. However, the strong and significant correlation between the 6MWT and VT values demonstrates the potential of the 6MWT to measure functional capacity for community-based exercise screening and patient monitoring. Further research is needed to develop a more accurate means of implementing and interpreting a self-administered 6MWT to facilitate pre-exercise screening and patient assessment for distance-based health care and research purposes.
6-minute walk test
cardiopulmonary exercise test
mean clinically important difference
rate of perceived exertion
Unified Theory of Acceptance and Use of Technology
peak oxygen uptake
ventilatory threshold
The authors would like to thank all participants who agreed to participate in this study. JST was funded by a Canadian Institute of Health Research Fellowship for the duration of this study. Both JST and SCA played a role in the conceptualization, planning, and administering of the study assessments, analysis of data, and manuscript preparation. CMS had a role in the conceptualization and planning of the study, overseeing the study assessments and analysis, and manuscript preparation. All authors have reviewed and approved the final manuscript.
None declared.