Figure 1From: Exoskeletons and orthoses: classification, design challenges and future directionsShoes and exoskeletons that act in series with the human lower limb. Examples are the Springbuck shoe [10, 11], the PowerSkip exoskeleton http://www.powerskip.de, and the SpringWalker exoskeleton [12] shown in 1a, 1b, and 1c, respectively.Back to article page