Arm-cycling is a versatile exercise modality with applications in both athletic enhancement and rehabilitation, yet the influence of forearm orientation remains understudied. Thus, this study aimed to investigate the impact of forearm position on upper-body arm-cycling Wingate tests. Fourteen adult males (27.3 ± 5.8 years) underwent bilateral assessments of handgrip strength in standing and seated positions, followed by pronated and supinated forward arm-cycling Wingate tests. Electromyography (EMG) was recorded from five upper-extremity muscles, including anterior deltoid, triceps brachii lateral head, biceps brachii, latissimus dorsi, and brachioradialis. Simultaneously, bilateral normal and propulsion forces were measured at the pedal-crank interface. Rate of perceived exertion (RPE), power output, and fatigue index were recorded post-test. The results showed that a pronated forearm position provided significantly (p < 0.05) higher normal and propulsion forces and triceps brachii muscle activation patterns during arm-cycling. No significant difference in RPE was observed between forearm positions (p = 0.17). A positive correlation was found between seated handgrip strength and peak power output during the Wingate test while pronated (dominant: p = 0.01, r = 0.55; non-dominant: p = 0.03, r = 0.49) and supinated (dominant: p = 0.03, r = 0.51; don-dominant: p = 0.04, r = 0.47). Fatigue changed the force and EMG profile during the Wingate test. In conclusion, this study enhances our understanding of forearm position's impact on upper-body Wingate tests. These findings have implications for optimizing training and performance strategies in individuals using arm-cycling for athletic enhancement and rehabilitation.

• While the supinated forearm position demonstrated superior neuromechanical efficiency in terms of propulsion force during the pulling phase, the pronated forearm position exhibited greater upward force during the pushing stages.

• The potential advantages of customizing these techniques to enhance performance with upper-body cycling could be specifically valuable for individuals managing spinal lesions, allowing for targeted muscle engagement. Hence, it allows for accommodation to navigate functional limitations.

• Additionally, the study emphasizes the significance of handgrip strength as a potential predictor of upper-body anaerobic power, particularly in the seated position, highlighting its relevance as an indicator of overall physical performance.

• The observed reductions in EMG activity as the Wingate test progressed may reflect alterations in supraspinal and spinal excitability.