The purpose of this study was to investigate the effectiveness of the progressive time delay (PTD) procedure on teaching gross motor skills to adult males with severe mental retardation. A multiple probe design across three skills and replicated across 4 participants was utilized. Results indicated that a PTD procedure with a 0 to 5 s delay was effective in teaching 4 participants three gross motor skills (tee-ball batting, softball pitching, croquet striking) over a period of 13 weeks. Data on effectiveness were analyzed in terms of the number of instructional sessions (M = 9.58), the number of trials (M = 105.41), the number of min (M = 84.66), and the number of performing errors to criterion (M = 4.08%). A maintenance level (M = 96.87%) was also determined across 4 participants and three skills on the 1st, 4th, 14th, and 24th sessions after terminating the PTD instruction.
Shihui Chen is with the Department of Health and Kinesiology at the University of Texas-Pan American, 1201 West University Drive, Edinburg, TX 78539. Email: <firstname.lastname@example.org>. Jiabei Zhang is with the Department of Health and Physical Education at Western Michigan University. Ernest Lange and Paul Miko are with the Division of Physical Performance and Development at the University of New Mexico. Daniel Joseph is with the Department of Health and Physical Education at Coppin State College.