WITHERS, R.T. Physiological responses of international female lacrosse players to pre-season conditioning. Med. Sci. Sports. Vol. 10, No. 4, pp. 238-242, 1978.—This study examined the changes in body composition, maximum aerobic power (V̇o2max) and maximum anaerobic power in seven Australian international women lacrosse players during a 3-month pre-season conditioning program. Monthly tests were conducted and the data were analyzed by an ANOVA repeated measures design and subjected to a polynomial orthogonal test of trend in the event of a significant F-ratio at the .05 level. The trend analysis for relative body fat (JOURNAL/masis/04.02/00005756-197810040-00003/ENTITY_OV0398/v/2017-12-20T204311Z/r/image-png = 24.9 [initial], 22.8, [first month], 23.1 [second month] and 23.1% [third month]) indicated significant linear and quadratic components since the major adjustment had occurred by the end of the first month. The players also experienced an overall average weight loss of 1.55 kg. The mean V̇o2max values were: 44.0, 48.6, 52.3 and 52.9 ml/kg x min. Thus aerobic power had plateaued by the end of the second month and the trend analysis accordingly indicated significant linear and quadratic components. Anaerobic alactacid power was measured by Margaria's stair run. Both the times and power (kgm/kg x sec) exhibited significant linear trends. Post-exercise blood samples taken at the start and end of the 3-month training program indicated a significant increase (P < .05) in lactate (X = 9.0 and 11.8 mmol/l) following a short duration maximum treadmill run.