Short Sprint Interval Training in People With Multiple Sclerosis

Cognitive processing speed will be assessed through the oral version of the Symbol Digit Modalities Test (SDMT). The outcome will be reported as the total number of correct responses. Scores range from 0 to 110, with higher scores indicating better cognitive processing speed. Change from baseline to Week 4 will be evaluated.

Fatigue severity will be assessed through the Fatigue Severity Scale (FSS). The FSS includes 9 items, each scored from 1, indicating strongly disagree, to 7, indicating strongly agree. The total score is calculated as the mean of the 9 items and ranges from 1 to 7, with higher scores indicating greater fatigue severity. Change from baseline to Week 4 will be evaluated.

Walking speed will be assessed through the Timed 25-Foot Walk (T25FW). This test will be performed forwards and backwards, at a comfortable pace and as fast as safely possible, with 2 trials for each condition. Time will be recorded in seconds using a stopwatch. The outcome will be reported as the lowest time recorded for each condition, with lower times indicating a faster walking speed. Change from baseline to Week 4 will be evaluated.

Dynamic walking performance and lower-limb coordination will be assessed through the Six-Spot Step Test (SSST). The SSST will be performed after a familiarization trial as fast as safely possible for two trials with each leg. Time will be recorded in seconds using a stopwatch, with lower times indicating better lower-limb coordination and walking performance. The outcome will be reported as the lowest time recorded for each leg. Change from baseline to Week 4 will be evaluated.

Handgrip strength will be assessed using a hand dynamometer and recorded in kg. The outcome will be the best of 3 trials, with higher scores indicating greater handgrip strength. Change from baseline to Week 4 will be evaluated.

Lower-limb muscle power will be assessed through the 5-repetition Sit-to-Stand test (5-STS) with the time recorded in seconds with a stopwatch. The outcome will be reported as the best of the 2 trials, with lower times indicating greater muscle power. Change from baseline to Week 4 will be evaluated.

Lower-limb endurance and strength will be assessed through the 30-second Sit-to-Stand test (30-STS), with the number of repetitions visually counted. The outcome will be reported as the best of 2 trials, with a higher number of repetitions indicating greater lower-limb endurance and strength. Change from baseline to Week 4 will be evaluated.

Cardiorespiratory fitness will be assessed using the Young Men's Christian Association 3-minute step test (YMCA step test). Heart rate will be assessed with a chest strap heart-rate monitor. The outcome will be recorded as the mean recovery heart rate after 60 s of rest, with lower scores indicating better cardiorespiratory fitness. Change from baseline to Week 4 will be evaluated.

Plantar flexor strength-endurance will be assessed using the standing single-leg heel-rise test. The outcome will be reported as the number of repetitions visually counted from each leg in 1 trial, with a higher number of repetitions indicating greater plantar flexor endurance capacity. Change from baseline to Week 4 will be evaluated.

Data will be recorded during each intervention session and will be used as descriptive data.

Cadence will be recorded using the potentiometer of the recumbent cycle ergometer by a custom software app in revolutions per minute.

Data will be recorded during each intervention session and will be used as descriptive data.

Heart rate will be recorded using the handheld sensors of the recumbent cycle ergometer by a custom software app in beats per minute.

Data will be recorded during each intervention session and will be used as descriptive data.

Power output will be recorded using the potentiometer of the recumbent cycle ergometer by a custom software app in watts.

Rating of perceived exertion (RPE) will be assessed using the Borg Category-Ratio 10 scale (CR10). Scores range from 0 to 10, with 0 indicating rest and 10 indicating maximal effort. The outcome will be reported as the perceived exertion score recorded after each sprint, with lower scores indicating lower perceived exertion.

Global session rating of perceived exertion (sRPE) will be assessed after each exercise session using the Borg Category-Ratio 10 scale (CR10). Scores ranges from 0 to 10, with 0 indicating rest and 10 indicating maximal effort. The outcome will be reported as the session perceived exertion score, with lower scores indicating lower perceived exertion.

Affective valence will be assessed after every sprint in the short sprint interval training intervention using the Feeling Scale. This scale ranges from -5 to +5, with +5 indicating very good, 0 indicating neutral, and -5 indicating very bad. The outcome will be reported as the affective valence score, with higher scores indicating better affective valence.

Height measured in meters.

Body mass measured in kilograms.

Body mass index measured through the combination of weight and height reported in kg/m^2.

Waist circumference and Hip circumference will be measured in centimeters.

Waist circumference and Hip circumference will be combined to report Waist-to-hip ratio as an index.

Smoking status will be reported by the patient with yes or no.

Most affected side will be reported by the patient as left, right, or both.

Limb dominance will be reported by the patient as left, right, or ambidextrous.

Patient-reported walking ability over the previous 2 weeks will be assessed using the 12-Item Multiple Sclerosis Walking Scale (MSWS-12). Items are scored on a Likert scale from 1 to 5, with 1 indicating "Not at all" and 5 indicating "Extremely". Scores range from 12 to 60 and are transformed into a percentage. The outcome will be reported as the percentage, with higher percentages indicating a greater perceived impact of MS on walking.

Fatigue over the previous 4 weeks will be assessed using the Modified Fatigue Impact Scale (MFIS). Items are scored on a Likert scale from 0 to 4, with 0 indicating "Never" and 4 indicating "Almost always". Total scores range from 0 to 84. The outcome will be reported as the total score, with higher scores indicating a greater impact of fatigue.