Periodized training programs seem to augment muscle performance (i.e., hypertrophy, strength and muscle endurance), however, optimal repetition ranges to achieve these adaptations are unclear. Thus, the purpose was to compare high and low repetition daily undulating periodization (DUP) models, with equal volume on performance. Eleven trained, college-aged males were counterbalanced into high (DUPHR) or low (DUP-LR) repetition groups. Subjects performed the squat and bench press 3X/wk. for 8wks. Outcome measures included one-repetition maximum (1RM) bench press, squat, and total strength (TS=squat+bench press), and muscle thickness (MT). 1RM strength increased with no difference between groups. Both groups increased total chest and total body MT (p<0.05); but only DUP-HR increased thigh MT (p<0.05). Effect sizes showed meaningful differences in strength favoring DUP-LR for bench press-1.48 and TS-0.89. Our findings indicate with equal volume, there may be meaningful differences in strength that are repetition-dependent, and varying responses to MT across different muscle groups. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection