High-intensity treadmill training improves gait ability, VO2peak and cost of walking in stroke survivors: preliminary results of a pilot randomized controlled trial

BACKGROUND: Stroke is a major cause of death and long-term disability across the globe. Previous studies have demonstrated the trainability of stroke survivors and documented beneficial effects of aerobic exercises on cardiovascular fitness and gait ability. AIM: The main aim of this study was to compare the effects of a high-intensity treadmill training (HITT) against low-intensity treadmill training (LITT) on gait ability, quality of life, cardiorespiratory fitness and cost of walking in chronic stroke subjects. DESIGN: Randomized, controlled pilot study. SETTING: Patients were recruited among Neurorehabilitation Unit outpatient. POPULATION: The sample was composed of 16 subjects suffering from chronic stroke. METHODS: Subjects were enrolled and randomly allocated either in the HITT (n=8) or in the LITT (n=8). Both groups performed 3-month training, 3 times per week. Subjects were evaluated before starting the training and after the end of the training by mean of clinical scales (Six Minute Walk Test, Ten Meter Walk Test, Health Survey Questionnaire SF-36, Stroke Impact Scale) and instrumental tests (Gait analysis, V02peak and Walking Energy Cost). RESULTS: Fifteen subjects completed the study and no dropouts were observed. One patient in the LITT refused to initiate the training. The HITT group produced greater improvements than LITT group on the Six Minute Walk Test (HITT: 644 meters, LITT: 6 meters; p=0.005) and Ten Meter Walk Test performances (HITT: -1,7 seconds, LITT: 0,6 seconds; p=0.007), stride length (HITT: 3,3 centimetres, LITT: 0,4 centimetres, p=0.003), step length non-paretic side (HITT: 0,5 centimetres, LITT: 2,4 centimetres, p=0.008), step length paretic side (HITT: 1,8 centimetres, LITT: 0,7 centimetres, p=0.004), cadence (HITT: 1,6 step/minute, LITT: 0,6 step/minute, p=0.021) and symmetry ratio (HITT: 0,04, LITT: 0,01, p=0.004), V02peak (HITT: 4,6 ml/kg/min, LITT: 0,87 ml/kg/min; p=0.015) and Walking Energy Cost at 100% of self-selected speed (HITT: -30,8 ml/kg*km, LITT: -20,5 ml/kg*km; p=0.021). Significant changes were found on Six Minute Walk Test (p=0.012) and Ten Meter Walk Test (p=0.042) performances, spatio-temporal gait parameters (stride length p=0.011, step length paretic side p=0.012, cadence p=0.037 and symmetry ratio p=0.012), VO2peak (p=0.025) and cost of walking at 100% of self-selected speed (p=0.018) in the HITT group. In the LITT no significant results were observed. CONCLUSION: HITT could be considered a feasible training and led to improvement in gait ability and enhanced VO2peak and reduction in cost of walking compared to LITT. CLINICAL REHABILITATION IMPACT: Chronic stroke survivors should be encouraged to engage regular aerobic treadmill training at medium/high intensity. HITT is safe and feasible and has positive effects on gait ability, cardiovascular fitness and cost of walking in subjects with stroke in chronic phase.