A Closed Kinetic Chain Task Utilizing an Immersive Virtual Reality-Based Platform Acutely Improves Shoulder Joint Position Sense in Collegiate Baseball Athletes

High-velocity baseball pitches place demands on the shoulder, requiring precise sensorimotor control to maintain joint stability and consistent throwing mechanics. Immersive virtual reality (IVR) has emerged as a platform for sensorimotor training, offering controlled, interactive environments, although its immediate effects on shoulder joint position sense remain unknown in overhead athletes. This preliminary within-subject pilot study evaluated whether a brief IVR-based closed kinetic chain (CKC) task using the ICAROS Lightning device could acutely improve active joint position sense (AJPS) in the dominant arm of collegiate baseball players. Nine male collegiate baseball athletes completed baseline AJPS testing during shoulder internal and external rotation before a 2-min immersive flight simulation task, then repeated AJPS assessment. Absolute angular error was the primary outcome. Following the intervention, AJPS error was significantly reduced in both rotational directions. Mean internal rotation error decreased by 4.22° (95% CI: 3.02° to 5.42°; p < 0.001; Cohen’s dz = 2.70), while mean external rotation error decreased by 4.73° (95% CI: 3.10° to 6.37°; p < 0.001; Cohen’s dz = 2.23). These preliminary findings suggest IVR-based CKC exercise acutely improves shoulder joint position sense, which may have implications for restoring proprioception following throwing-induced fatigue. Further validation is warranted in randomized controlled studies with larger, heterogeneous samples in order to determine whether these findings have meaningful effects on throwing performance or recovery.