Ingebrigtsen, J, Shalfawi, SAI, Tønnessen, E, Krustrup, P, and Holtermann, A. Performance effects of 6 weeks of aerobic production training in junior elite soccer players. J Strength Cond Res 27(7): 1861–1867, 2013—This study investigates the performance effects of a 6-week biweekly anaerobic speed endurance production training among junior elite soccer players. Sixteen junior (age 16.9 ± 0.6 years) elite soccer players were tested in the Yo-Yo Intermittent Recovery test level 2 (IR2), 10-m and 35-m sprints, 7 × 35-m repeated-sprint ability (RSA) tests, countermovement jump and squat jump tests, and randomly assigned to either a control group (CG) performing their normal training schedule, which included 4 weekly soccer training sessions of approximately 90 minutes, or a training group performing anaerobic speed endurance production training twice weekly for 6 weeks in addition to their normal weekly schedule. We found that the intervention group significantly improved (p < 0.05) their performance in the Yo-Yo IR2 (63 ± 74 m) and 10-m sprint time (−0.06 ± 0.06 seconds). No significant performance changes were found in the CG. Between-group pretest to posttest differences were found for 10-m sprint times (p < 0.05). No significant changes were observed in the 35-m sprint times, RSA, or jump performances. These results indicate that short-term anaerobic production training is effective in improving acceleration and intermittent exercise performance among well-trained junior elite players.