Thesis draft Title: High-intensity interval training programmes in female/male team sports athletes Type of the study: longitudinal study; 12-24 weeks experimental programme; randomized controlled study Participants: team sports athletes (football, basketball, handball, etc); 20-40 participants, male or female (better female) Measurements: body composition, fitness, repeated sprint abilities, aerobic and anaerobic capacity, etc (to be negotiated with candidate(s)) Instruments: Tanita BC540; Opto jump, Polar or GPS tracker, Cosmed or similar, Monark ergometer, etc. Procedure: We will create individually based HIIT according to maximal aerobic speed reached by athletes. After that, we will implement HIIT programme during pre-season or in-season period once or two times per week. There is possibility to develop several different HIIT modes including HIIT with multiple turns (most specific to team sports) or HIIT performed with a ball (this will be negotiated with candidate). In some team sports (basketball, handball) we could compare small-sided games with HIIT. This topic is very popular in football but already well documented in literature. Probably we could perform comparison between SSG and HIIT in female football teams.