The purpose of this investigation was to examine the effect of supplementing specific practice with variable practice and subjective estimation on movement bias, consistency, and error-detection capabilities in a coincident anticipation task. Forty-eight students volunteered to participate. Two practice conditions were examined. The Specific condition practiced a total of 270 acquisition trials at 3.1 m/s. The Specific + Variable condition practiced a total of 270 acquisition trials with 90 trials performed at 2.2 m/s, 3.1 m/s, and 4.0 m/s. Two estimation conditions were also examined. The 100% estimation condition verbally estimated subjective error 5 s after each movement in the acquisition phase, whereas the 0% estimation condition did not estimate subjective error. At the beginning of the investigation, participants were instructed to depress a hand-held thumb control button at the same time the final light of the runway illuminated. There were three phases: the acquisition phase of 90 trials for three consecutive days; a 24-hr no-KR retention test of 10 trials at 3.1 m/s; and a 24-hr no-KR transfer test of 20 trials with 10 trials at 1.3 m/s and 4.9 m/s. Absolute constant error (|CE|), mean absolute difference between objective and subjective (|O-S|) error, and variable error (VE) for trials in acquisition phase, retention phase, and transfer phase were calculated into trial blocks of 10 trials. Trials in the retention phase were analyzed in a 2 x 2 (Practice Condition x Estimation Condition) factorial ANOVA and revealed no significant differences between practice conditions or estimation conditions for |CE| and VE. For mean |O-S| error, there were no significant differences between practice conditions in the 100% estimation condition. The Specific + Variable condition performed with significantly smaller error than the Specific condition in the 0% estimation condition. Transfer trials were analyzed in a 2 x 2 x 2 (Practice Condition x Estimation Condition x Velocity) factorial ANOVA with repeated measures on the third factor and revealed the Specific + Variable condition performed with significantly smaller |CE| and VE than the Specific condition. For mean |O-S| error, there were no significant differences between practice conditions in the 100% estimation condition. The Specific + Variable condition performed with significantly smaller error than the Specific condition in the 0% estimation condition. Retention and transfer results support the finding that supplementing specific practice with variable practice in acquisition strengthens error-detection capabilities and may explain the benefit of supplementing specific practice with variable practice.