Abstract Differences in physiological, physical, and technical demands of small-sided basketball games related to the number of players, court size, and work-to-rest ratios are not well characterised. A controlled trial was conducted to compare the influence of number of players (2v2/4v4), court size (half/full court) and work-to-rest ratios (4x2.5 min/2x5 min) on the demands of small-sided games. Sixteen elite male and female junior players (aged 15-19 years) completed eight variations of a small-sided game in randomised order over a six-week period. Heart rate responses and rating of perceived exertion (RPE) were measured to assess the physiological load. Movement patterns and technical elements were assessed by video analysis. There were *60% more technical elements in 2v2 and *20% more in half court games. Heart rate (86 + 4% & 83 + 5% of maximum; mean + SD) and RPE (8 + 2 & 6+ 2; scale 1-10) were moderately higher in 2v2 than 4v4 small-sided games, respectively. The 2v2 format elicited substantially more sprints (36 +12%; mean +90% confidence limits) and high intensity shuffling (75 +17%) than 4v4. Full court games required substantially more jogging (9 +6%) compared to half court games. Fewer players in small-sided basketball games substantially increases the technical, physiological and physical demands
