Figure 1
Databases utilized and corresponding search terms
| Database | Search query |
|---|---|
| ScienceDirect | “exoskeleton” AND “prolonged standing” AND “industrial workers” AND “lower limb” AND “muscle fatigue” |
| PubMed | (exoskeleton) AND (industrial workers) AND (muscle fatigue) |
| Scopus | “exoskeleton” AND “muscle fatigue” AND “lower limb” AND “standing” |
| Manual searching | lower limb exoskeleton in manufacturing industry for prolonged standing to reduce fatigue and discomfort |
Lower-limb exoskeleton (commercial)
| Name of Exoskeletons | Institute/country/year | Types of exoskeletons | Weight (kg)/Maximum load capacity of the device (N) | Materials | Assessment technique | Main findings | Citations |
|---|---|---|---|---|---|---|---|
| Noonee | Noonee AG./Switzerland/2014 | Passive (hydraulic) | 3.3/120 | Polymers | Electromyography (EMG) (muscle activity) | 64% reduction in lower extremity strain | Luger et al. (2019) |
| LegX | U.S. Bionics dba SuitX/USA/2018 | Passive (spring system) | 6.2/100 | — | EMG (muscle activity) | 56% reduction in muscle activity | Pillai et al. (2020) |
| H-CEX | Hyundai Motor Company/Korea/2018 | Passive (four-bar linkage) | 1.6/150 | — | EMG (muscle activity) and interview | 30.59–84.08% reduction, positive feedback on comfort | Kong et al. (2021) |
| Archelis | Nitto Ltd/Japan/2016 | Passive (mechanical lock) | 5/80 | Polymers | EMG (muscle activity) | Reduces iliopsoas muscle activation | Kawahira et al. (2018) |
| Honda bodyweight support | Honda R&D Co., Ltd/Japan/2016 | Active (Electric motor, 4-bar linkage) | 6.5/100 | — | EMG (muscle activity) and oxygen – energy consumption/11% | 18% reduction in muscle activity | Ikeuchi et al. (2009) |
Lower-limb exoskeleton (research models)
| Name of exoskeletons | Institute/country/year | Types of exoskeletons | Weight (kg)/maximum load capacity of the device (N) | Materials | Assessment technique | Main findings | Citations |
|---|---|---|---|---|---|---|---|
| Semi-active exoskeleton | University of Electronic Science and Technology of China, China/2020 | Semi-active (rigid-support mode, elastic-support mode, follow mode) | 2.6/– | Al alloy, carbon fibre | EMG (muscle activity) | Reduced muscle fatigue across three operating modes | Wang et al. (2021) |
| SIAT-leg | Huazhong University of Science and Technology/China/2020 | Passive | 2/100 | Mild steel, carbon fibre | EMG (muscle activity) and comfort scale | 44.8–71.5% reduction> 70% comfort rating | Yan et al. (2021) |
| Single-stand chairless exoskeleton | Universiti Teknikal Malaysia Melaka/Malaysia/2024 | Passive | 3/1,090 | Al alloy, polyurethane foam, nylon, steel | EMG (muscle activity) | Reduced contact pressure by 71% single-stand – system usability scale (SUS) of 79.5 (P-value < 0.05) | Halim et al. (2024) |
| HUST-EC | Huazhong University of Science and Technology/China/2019 | N/A | –/87 | Al alloy | EMG (muscle activity) | 80% average reduction in muscle activity | Han et al. (2019) |
| Chair X | University of Moratuwa/Sri Lanka/2019 | N/A | 13.4/80 | Al alloy, mild steel, glass fibre | EMG (muscle activity) | 20% reduction in muscle activity | Wijegunawardana et al. (2019) |
| Passive weight-support exoskeleton | Xi’an Jiaotong University/China/2018 | Passive (spring system) | 2/– | — | EMG (muscle activity) | 83% max reduction in muscle activity | Zhu et al. (2018) |
| CCES | Nehru College of Engineering and Research Centre/India/2018 | Passive (Gas strut) | 3.68/140 | Al alloy | — | — | Ramachandran et al. (2018) |
| Chairless chair | K J College of Engineering and Management Research/India/2017 | N/A | — | Mild steel | — | — | Siddha et al. (2018) |
| Knee assist robotic exoskeleton | Kwangwoon University/Korea/2016 | Active (pneumatic power) | 8/80 | — | EMG (muscle activity) | Muscle activity reduction in static postures | Noh et al. (2016) |
| SimpChair | University of Malaysia Pahang/Malaysia/2015 | Passive (gas strut) | 3/100 | Mild steel | — | — | Allias et al. (2015) |
| Passive weight- support LEE | Huazhong University of Science and Technology/China/2015 | Passive | 1.95/63.5 | Al alloy, mild steel | — | — | Lee and Wang, (2015) |
| Soft gait | Korea Advanced Institute of Science and Technology/Korea/2015 | Active (pneumatic power) | 8.25/650 | Metal | Foot reaction force | 83% reduction in reaction force | Hong et al. (2015) |