Table 1

Outcomes for MSTEP Study
Construct Measure Clinically relevant change
Primary Outcome
Exercise capacity V02peak 10% change[32,55,56]
Components of Global Outcome
Exercise efficiency: Gross, net and work efficiency Gross efficiency = work performed / energy expended × 100%, Net efficiency = work performed / energy expended above rest × 100%, and Work efficiency = work performed / energy expended above that in cycling at 0 W × 100% [57]. 10% change [58].
Sub-maximal exercise capacity The Modified Canadian Aerobic Fitness Test (mCAFT) is a multi-stage step-test, simple to use and inexpensive, that assesses sub-maximal aerobic capacity [59]. 1 stage [59]
Functional ambulation Modified 6 Minute Walk Test (M-6MWT) [60]; distance and fatigability index calculated by [the distance walked in the last minute ÷ distance walked in the first minute], with ratio ≥ 1.0 indicating less fatigability; Reliability high (ICC across 3 walks, 0.95). 50 m. [32,60-64].
Strength Grip, vertical jump, push-ups, curl-ups [65] ½ SD: jump 5cm; curl ups 5; push ups 3; grip strength 12 [46].
Fatigue symptoms Unidimensional Fatigue Impact Scale [66]; which is a Rasch validated measure of fatigue modeled from the original and modified versions [60,67] Minimum clinically important difference(MCID) 5; ½ SD = 6 [66].
Mood* Rand-36 MHI subscale [68,69]; Meaningful change: 10
Global physical function* Rand-36 PF subscale [68,69] Meaningful change = 10
Health perception* EQ-5D [70-73] Meaningful change = 10
Quality of life* Patient Generated Index* [74,75] Meaningful change ½ SD = 12.5
Explanatory Variables
Current disability level PDDS (patient version of EDSS) for all persons [76]
Relapses Defined as “patient-reported or objectively observed events typical of an acute inflammatory demyelinating event in the CNS, current or historical, with duration of at least 24 hours, in the absence of fever or infection.” [47]; annualized rate over study period
Exercise adherence Exercise diary (paper, computer version) daily for 3 months, 1 week every 3 months subsequently; accelerometers worn for 1 week every 3 months (see response to reviewers on feasibility of this) ActivPal [77]
Exercise self-efficacy 3 item questionnaire with demonstrated validity and test-retest reliability (>0.85) [78]
Exercise barriers and benefits The benefits subscale of the Exercise Benefits/Barriers Scale will be used [79] along with 4 indicators for barriers shown to be independent predictors of exercise engagement [21,44]

* Data from ½ SD from PGI and SF-36 subscales from recently completed CIHR pilot grant on Gender differences in Life Impact of MS which is described in the first publication from this data set [46].

Mayo et al.

Mayo et al. BMC Neurology 2013 13:69   doi:10.1186/1471-2377-13-69

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