Objectves: This study assessed the effects of a four-week upper-body wobbleboard training program on discrimination of forearm-raising movements at the post-dislocation shoulder. Design: Pre- and post-measures on a treatment group and control group. Subjects: Sixty shoulders were tested from 15 subjects with previous anterior dislocations and from 15 uninjured subjects. Methods: During the four-week period, the dislocator group trained lying over a Swiss ball and balancing their upper body on a wobbleboard. The control group, included to check any learning effects on the discrimination test, undertook no training during this period. Movement discrimination tests of a 'policeman's stop' action were conducted in weight-bearing stance, with forward vision available, both pre and post the training period. Five locations between 0.95 and 4.77 cm forward of true vertical were used for the discrimination movements, and each shoulder was tested with a series of 100 forearm-raising movements giving external rotation at the shoulder. Absolute judgements were made, with subjects naming the distance on each trial using the numbers 1-5. Non-parametric signal detection receiver operating characteristic analysis was applied to obtain a discrimination score. Results: Following one month of upper-body wobbleboard training, there was a significant movement discrimination improvement at the shoulders of previous dislocators compared to controls, and a greater improvement for the involved compared to the uninvolved limb. Conclusion: Upper-body wobbleboard training can improve discrimination of shoulder movements in a position near to the dislocation posture for subjects who have had a shoulder dislocation in the previous 12 months.