PURPOSE: Instructions are an essential part of skill acquisition. Previous research (Wulf, 2007; Porter, 2010) has established that external focus of attention instruction (EFI) supersedes that of internal focus of attention instruction (IFI) on performance of a specific task. Tenants of dynamics systems theory however, dictate that a resulting performance occurs through the most optimal performance subsystems. Thus, as the constraints placed on a task shift so too does the performance of the system. Previously, Porter (2011) demonstrated that time on task (TT) performance on a novel rotary pursuit tracking task, at 15 rpms, was greatest with EFI compared to IFI. When the constraints on the task are altered, such as movement speed, it was hypothesized that self-organization of the subsystems would reduce the influence of instructions on performance outcomes. METHODS: 18 subjects (mean age=26.4; f=6; m=12) performed 3 x 30 s trials of a rotary tracking task in three experimental conditions at 40 rpm. The three conditions were: control (C), IFI and EFI. Conditions were counterbalanced to prevent an order effect with trials being performed on separate days. Data was analyzed using a 2 way repeated measures ANOVA 3 (instruction) x 3 (trial). RESULTS: Main effects for instruction (F2, 34= 7.19, p=0.002) and trial (F2, 34= 16.58, p=0.001) were observed between conditions. Post hoc analysis with Bonferroni adjustment indicated that both IFI and EFI demonstrated more TT than C, but were not different than each other (C= 18.21 SE= .88; IF = 20.24 SE = 1.08; EF = 21.32 SE = .92). CONCLUSIONS: Previous research would predict that EFI instruction would have more TT than IFI instruction. However, as evidenced by no differences between IFI & EFI conditions suggests performance is more greatly influenced by task constraints than focus of attention instructions. These findings suggest that movement practitioners should consider task constraints as a performance variable in conjunction with instructional considerations.