Klaske van Kammen1, Heleen A Reinders-Messelink2, Anne L Elsinghorst3, Carlijn F Wesselink4, Berna Meeuwisse-de Vries5, Lucas H V van der Woude6, Anne M Boonstra7, Rob den Otter8. 1. University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, the Netherlands; Rehabilitation Center 'Revalidatie Friesland', Beetsterzwaag, the Netherlands. Electronic address: k.van.kammen@umcg.nl. 2. Rehabilitation Center 'Revalidatie Friesland', Beetsterzwaag, the Netherlands; University of Groningen, University Medical Center Groningen, Center for Rehabilitation, Groningen, the Netherlands. Electronic address: h.reinders-messelink@revalidatie-friesland.nl. 3. University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, the Netherlands; Rehabilitation Center 'Revalidatie Friesland', Beetsterzwaag, the Netherlands. Electronic address: anneliseelsinghorst@hotmail.com. 4. University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, the Netherlands; Rehabilitation Center 'Revalidatie Friesland', Beetsterzwaag, the Netherlands. Electronic address: c.f.wesselink@umcg.nl. 5. Rehabilitation Center 'Revalidatie Friesland', Beetsterzwaag, the Netherlands. Electronic address: b.meeuwisse@Revalidatie-Friesland.nl. 6. University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, the Netherlands; University of Groningen, University Medical Center Groningen, Center for Rehabilitation, Groningen, the Netherlands. Electronic address: l.h.v.van.der.woude@umcg.nl. 7. Rehabilitation Center 'Revalidatie Friesland', Beetsterzwaag, the Netherlands. Electronic address: a.m.boonstra@revalidatie-friesland.nl. 8. University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen, the Netherlands. Electronic address: a.r.den.otter@umcg.nl.
Abstract
BACKGROUND: The Lokomat is a commercially available exoskeleton for gait training in persons with cerebral palsy (CP). Because active contributions and variability over movement repetitions are determinants of training effectiveness, we studied muscle activity in children with CP, and determined (i) differences between treadmill and Lokomat walking, and (ii) the effects of Lokomat training parameters, on the amplitude and the stride-to-stride variability. METHODS: Ten children with CP (age 13.2 ± 2.9, GMFCS level II(n = 6)/III(n = 4)) walked on a treadmill (±1 km/h; 0% bodyweight support(BWS)), and in the Lokomat (50% and 100% guidance; ±1 km/h and ±2 km/h; 0% and 50% BWS). Activity was recorded from Gluteus Medius (GM), Vastus Lateralis (VL), Biceps Femoris (BF), Medial Gastrocnemius (MG) and Tibialis Anterior (TA) of the most affected side. The averaged amplitude per gait phase, and the second order coefficient of variation was used to determine the active contribution and stride-to-stride variability, respectively. RESULTS: Generally, the amplitude of activity was lower in the Lokomat than on the treadmill. During Lokomat walking, providing guidance and BWS resulted in slightly lower amplitudes whereas increased speed was associated with higher amplitudes. No significant differences in stride-to-stride variability were observed between Lokomat and treadmill walking, and in the Lokomat only speed (MG) and guidance (BF) affected variability. CONCLUSIONS: Lokomat walking reduces muscle activity in children with CP, whereas altering guidance or BWS generally does not affect amplitude. This urges additional measures to encourage active patient contributions, e.g. by increasing speed or through instruction.
BACKGROUND: The Lokomat is a commercially available exoskeleton for gait training in persons with cerebral palsy (CP). Because active contributions and variability over movement repetitions are determinants of training effectiveness, we studied muscle activity in children with CP, and determined (i) differences between treadmill and Lokomat walking, and (ii) the effects of Lokomat training parameters, on the amplitude and the stride-to-stride variability. METHODS: Ten children with CP (age 13.2 ± 2.9, GMFCS level II(n = 6)/III(n = 4)) walked on a treadmill (±1 km/h; 0% bodyweight support(BWS)), and in the Lokomat (50% and 100% guidance; ±1 km/h and ±2 km/h; 0% and 50% BWS). Activity was recorded from Gluteus Medius (GM), Vastus Lateralis (VL), Biceps Femoris (BF), Medial Gastrocnemius (MG) and Tibialis Anterior (TA) of the most affected side. The averaged amplitude per gait phase, and the second order coefficient of variation was used to determine the active contribution and stride-to-stride variability, respectively. RESULTS: Generally, the amplitude of activity was lower in the Lokomat than on the treadmill. During Lokomat walking, providing guidance and BWS resulted in slightly lower amplitudes whereas increased speed was associated with higher amplitudes. No significant differences in stride-to-stride variability were observed between Lokomat and treadmill walking, and in the Lokomat only speed (MG) and guidance (BF) affected variability. CONCLUSIONS: Lokomat walking reduces muscle activity in children with CP, whereas altering guidance or BWS generally does not affect amplitude. This urges additional measures to encourage active patient contributions, e.g. by increasing speed or through instruction.