Herrington, L. The effects of 4 weeks of jump training on landing knee valgus and crossover hop performance in female basketball players. J Strength Cond Res 24(12): 3427-3432, 2010-Female basketball players would appear particularly prone to knee injuries. These injuries have been associated with the nature of the sport, but more specifically with the particular movement strategies adopted. A valgus or abducted position of the knee on landing has been reported to be associated with a number of different knee injuries. Jump-training programs have been reported to improve both landing knee valgus and functional performance. The majority of the jump-training programs have been of 6 weeks' duration, 3 sessions per week often lasting up to 1 hour. For most sports coaches, team conditioners, and athletes, this duration and program length is not acceptable. The aim of this study was to assess if an abridged jump-training program could have similar effects to those previously reported. Fifteen female basketball players had their knee valgus angles assessed during 2 landing tasks, drop jump landing, and when undertaking a jump shot and along with crossover hop distance before and after a progressive jump-training program. The jump-training program lasted 4 weeks, 3 times per week, each session lasting 15 minutes. After training, crossover hop distance showed an average percentage improvement on distance jumped of 73.6% (p = 0.001); the drop jump knee valgus angle in the left leg on average was reduced by 9.8° (p = 0.002), right leg reduced by 12.3° (p = 0.0001); during the jump shot, the knee valgus angle in the left leg showed a mean reduction of 4.5° (p = 0.035), and the right leg was reduced by 4.3° (p = 0.01). The study undertaken achieved comparable results to those previously reported with an abridged program over considerably shortened session duration and training period.