Pilot investigation of the oxygen demands and metabolic cost of incremental shuttle walking and treadmill walking in patients with cardiovascular disease

Abstract

ObjectiveTo determine if the metabolic cost of the incremental shuttle-walking test protocol is the same as treadmill walking or predicted values of walking-speed equations.SettingPrimary care (community-based cardiac rehabilitation).ParticipantsEight Caucasian cardiac rehabilitation patients (7 males) with a mean age of 67±5.2 years.Primary and secondary outcome measuresOxygen consumption, metabolic power and energy cost of walking during treadmill and shuttle walking performed in a balanced order with 1 week between trials.ResultsAverage overall energy cost per metre was higher during treadmill walking (3.22±0.55 J kg/m) than during shuttle walking (3.00±0.41 J kg/m). There were significant post hoc effects at 0.67 m/s (p<0.004) and 0.84 m/s (p<0.001), where the energy cost of treadmill walking was significantly higher than that of shuttle walking. This pattern was reversed at walking speeds 1.52 m/s (p<0.042) and 1.69 m/s (p<0.007) where shuttle walking had a greater energy cost per metre than treadmill walking. At all walking speeds, the energy cost of shuttle walking was higher than that predicted using the American College of Sports Medicine walking equations.ConclusionsThe energetic demands of shuttle walking were fundamentally different from those of treadmill walking and should not be directly compared. We warn against estimating the metabolic cost of the incremental shuttle-walking test using the current walking-speed equations.

Incremental Shuttle Walk Test to Assess and Prescribe Exercise for Subjects With Bronchiectasis: Hallway Versus Treadmill

“…In a previous study, subjects with cardiac disease demonstrated a poorer performance on a treadmill than in a hallway due to the greater energy expenditure required (3.22 Ϯ 0.55 J/kg/m vs 3.00 Ϯ 0.41 J/kg/m). 9 Our findings were different. A plausible explanation for this result is that all participants used the handrail for support, which demonstrates that this resource influences physiological responses, leading to better performance on the ISWT-T.…”

“…Compared to the ISWT-H, a substantial reduction in the walking distance has been demonstrated for the 6-min walk test, 4,5 the 12-min walk test, 6,7 and the ISWT 8 when performed on a treadmill, along with a higher energy cost per meter on the ISWT. 9 Indeed, there are important differences in gait mechanics between walking on a treadmill and walking in a hallway. 5,[9][10][11] A treadmill requires greater effort and energy to maintain lateral balance and is an activity with which many patients are not familiar.…”

“…9 Indeed, there are important differences in gait mechanics between walking on a treadmill and walking in a hallway. 5,[9][10][11] A treadmill requires greater effort and energy to maintain lateral balance and is an activity with which many patients are not familiar. [11][12][13] Therefore, because the 2 methods of performing these tests are not interchangeable, the replacement of the hallway with a treadmill is not recommended.…”

Effects of exercise-based cardiac rehabilitation on cardiorespiratory fitness: A meta-analysis of UK studies

“…Prior to this analysis we undertook a pilot investigation to compare treadmill walking with more commonly used protocols involving shuttle-walking. [27] We found that the metabolic demands of treadmill walking were fundamentally different from shuttle-walking. On this basis, we excluded such data from the remaining eligible study.…”

“…(ml·kg -1 ·min -1 or Metabolic Equivalents [METs]) but consensus is currently lacking regarding the most appropriate method of estimation [25][26][27].…”