# Lower- Limb Exosuits for Rehabilitation or Assistance of Human Movement: A Systematic Review
## 3 Review
### Clinical Studies
Activity-specific tasks included \"get up and go\" (GUG) [33], \"timed get up and go\" (TUG) [42], \"sit-to-stand\" test [34], perturbed walk [33], the functional independence measure [23], \"Fugl-Meyer assessment of Motor Recovery after Stroke\" [37] and the Barthel index [23]. Energy expenditure by the user was assessed by indirect calorimetry [8; 28; 31], oxygen consumption, heart rate and respiratory rate [23]. The movement of the users was captured in eight studies with optical motion capture systems using reflective markers [8; 26; 27; 30; 31; 37; 40; 42]. Ground reaction forces, plantar pressure and balance were measured using a plantar foot pressure system [36] (one study), force plates [26; 27; 37; 39] (four studies) and instrumented treadmills [31; 40; 42] (three studies) to analyze the physical interaction between the exosuit user and the ground. Balance was measured with the Berg Balance Scale [23] and Biodex Balance System [36]. Commercial systems for gait measurement, Gaitrite [53] and Optogatit [54], were used to measure gait spatio-temporal parameters such as gait speed, cadence, step length, stride length and swing time [23; 34; 35; 38]. Muscle activity in the lower extremities was measured in four studies, using surface electromyography (EMG) [31; 32; 41; 42]. Questionnaires were used in three studies to gather data about subjective parameters via an 11-point numerical rating scale (NRS) [33; 39] or a custom questionnaire with rating from 0-5 [29]. Even though symptoms such as pain are difficult to measure due to their multifaceted and subjective nature [55], self-reported measures can be a reliant input in this kind of study [56]. Hence, subjective user feedback is of crucial importance for exosuit development. For soft lower-limb exosuits, a design evaluation tool (Exoscore) has been developed recently [57]. No evaluation was conducted concerning the intended environment for the exosuit. It is foreseen that exosuits can be used in different settings, such as hospitals, rehabilitation facilities, at home or outdoors. Every environment has its own set of requirements for the exosuit, which the design and development must address. Therefore, studies should include an evaluation of design requirements for the intended environments in the future. Additionally, to analyze the results of exosuit use, a study protocol should be established that not only includes gait analysis, but also balance tests and everyday tasks to reflect use in everyday conditions. The reviewed clinical studies did not address the ergonomics of use in detail, while ergonomic factors have been treated in other studies, for example, to evaluate the fixation of an exosuit by compression [58; 59]. Concerning ergonomics, studies mention that exosuits are better matched to the user's capabilities when compared to rigid exoskeletons [60], but no actual comparison between exosuits and rigid exoskeletons was found. A direct comparison of different systems by the same sample of subjects would provide a better picture of technical and ergonomic advantages and disadvantages, which might lead to the development of better exoskeletons and exosuits. The outcomes of clinical evaluations of lower-limb exosuits with users suffering from mobility impairment were overall positive. Outcomes from the reviewed studies with passive exosuits included the use of braces, elastic orthoses and elastic elements. Elastic ankle-foot orthoses (AFOs) had positive effects on controlling anterior-posterior body sway [36] and improved gait in hemiplegic users with spastic foot equinus [32]. Additionally, elastic AFOs were shown to improve velocity, cadence, step length, stride length and single-limb support in stroke patients [34], while varying the stiffness of ankle-foot orthoses had only a minimal effect on walking performance [27]. When using an elastic knee sleeve (or soft brace), knee adduction angles, moments and impulse in users with knee arthrosis were reduced [39].