Running on a lower-body positive-pressure (LBPP) treadmill allows effects of weight support on leg muscle activation to be assessed systematically, and has the potential to facilitate rehabilitation and prevent overloading. The aim was to study the effect of running with weight support on leg muscle activation and to estimate relative knee and ankle joint forces. Runners performed 6-min running sessions at 2.22 m/s and 3.33 m/s, at 100%, 80%, 60%, 40%, and 20% body weight (BW). Surface electromyography, ground reaction force, and running characteristics were measured. Relative knee and ankle joint forces were estimated. Leg muscles responded differently to unweighting during running, reflecting different relative contribution to propulsion and antigravity forces. At 20% BW, knee extensor EMGpeak decreased to 22% at 2.22 m/s and 28% at 3.33 m/s of 100% BW values. Plantar flexors decreased to 52% and 58% at 20% BW, while activity of biceps femoris muscle remained unchanged. Unweighting with LBPP reduced estimated joint force significantly although less than proportional to the degree of weight support (ankle).It was concluded that leg muscle activation adapted to the new biomechanical environment, and the effect of unweighting on estimated knee force was more pronounced than on ankle force.
Bente R. Jensen, Line Hovgaard-Hansen and Katrine L. Cappelen
Mhairi K. MacLean and Daniel P. Ferris
and complexity in the ambulatory tasks. Walking at a single speed on a treadmill is a good way of collecting data for a steady-state condition, but there are very few steady-state conditions in real-world ambulation. Walking in the real world is often over uneven and varied terrain, interspersed with
Yuko Kuramatsu, Yuji Yamamoto and Shin-Ichi Izumi
). Locomotor adaptation on a split-belt treadmill can improve walking symmetry post-stroke . Brain, 130 , 1861 – 1872 . PubMed ID: 17405765 doi:10.1093/brain/awm035 10.1093/brain/awm035 Roy , G. , Nadeau , S. , Gravel , D. , Malouin , F. , McFadyen , B.J. , & Piotte , F. ( 2006 ). The effect