Older adults often experience cognitive and functional decline, which can be mitigated by innovative interventions like immersive virtual reality (iVR). Self-adaptive serious games, which dynamically adjust task difficulty, may provide additional benefits by tailoring challenges to individual performance. However, the comparative effectiveness of self-adaptive versus progressive non-adaptive iVR interventions on motor learning in older adults remains underexplored. This randomized controlled trial primarily aimed to compare the effects of self-adaptive and progressive non-adaptive iVR interventions on motor learning in older adults. A total of 33 older adults were randomly assigned to either a self-adaptive (n = 17) or progressive non-adaptive (n = 16) iVR group. Both interventions involved an iVR serious game requiring unimanual reaching, target selection, and distractor inhibition under increasing difficulty over three days. Performance was evaluated pre- and post-intervention using a standardized iVR task, consisting of hitting a virtual target while ignoring distractors. This task features five levels of difficulty (level 0: no distractors
level 4: 17 low-saliency distractors). Primary outcomes, assessed during the standardized task, included changes in speed-accuracy trade-offs (SAT) and relative response time (RT, compared to level 0). Both participants and assessors were blinded to the intervention. After the intervention, both groups exhibited significant SAT improvements at level 1, 3 and 4 (P <
0.05) and RT gains at level 3 and 4 (P <
0.05). The self-adaptive group demonstrated significantly greater SAT (P = 0.049) and relative RT (P = 0.004) improvements at level 4. Findings suggest that older adults can achieve motor learning in iVR, particularly with self-adaptive serious games, highlighting potential for self-rehabilitation. Clinical trial NCT06141642 approved the 21th November 2023.