Theor. Appl. Ergon., Volume 2, Issue 1 (March 2026) – 2 articles

Exoskeletons are increasingly used in industrial settings, yet most are designed for structured, repetitive tasks, limiting adaptability to dynamic movements. In construction, frequent locomotion tasks demand continuous lower-limb engagement, and ladder climbing places substantial loads on coordination and flexibility. This study aimed to identify key muscles involved in climbing to support the development of adaptive exoskeletons. Ten healthy male participants (33.8 ± 3.4 years; 178.7 ± 5.0 cm; 87.4 ± 16.1 kg) performed vertical and A-frame ladder ascents in a controlled laboratory setting. Surface electromyography was recorded from eight right-leg muscles and processed using band-pass filtering, rectification, and root mean square smoothing. Two normalization strategies were applied: walking normalization, expressing climbing activity relative to level walking, and maximum voluntary contraction normalization, with amplitudes expressed as a percentage of maximum voluntary contraction. Our results showed that all muscles were more active in climbing than walking, with quadriceps (vastus medialis, vastus lateralis, rectus femoris) exhibiting the greatest increases. Gastrocnemius also approached or exceeded 100%MVC, tibialis anterior averaged 70–80%MVC, and hamstrings contributed 20–40%MVC mainly for stabilization. Vertical and A-frame ladders followed similar patterns with subtle posture-related variations. These findings highlight knee extensors as primary targets for adaptive exoskeleton assistance during ladder climbing tasks commonly performed on construction sites. Full article

Maximum aerobic capacity (MAC) helps in physical work capacity evaluation. In practice, the construction jobs are designed using the standard treadmill or ergometer MAC value, which is inappropriate and leads to injuries. According to NIOSH, the average oxygen consumption during an 8 h day is recommended to be no more than 33% of the exercise-specific MAC. Therefore, there is a necessity for construction activity-specific MAC exercise protocols and estimation models. The aim of the study is to develop MAC estimation models for common construction activities such as walking, carrying, lifting, and combined (carrying, dragging, hammering, lifting, and wrenching) using the submaximal exercise test mode. Ten male participants performed all four activities at three different intensities for five minutes each. The oxygen uptake and heart rate were recorded for each trial. This study shows that the average MAC value for walking, carrying, lifting, and combined activities is 0.779 gpm (2.95 L/m), 0.674 gpm (2.55 L/m), 0.745 gpm (2.82 L/m), and 0.608 gpm (2.30 L/m), respectively. The MAC value of combined construction activities is significantly lower than walking (28%), carrying (11%), and lifting (22%). The study recommends using a construction activity-specific exercise protocol for evaluating jobs or workers to prevent a mismatch between job demands and worker capabilities. Full article