AIM: The aims of the current study were, firstly, to quantify the motion characteristics of professional youth soccer players and, secondly, to develop and validate a soccer-specific exercise protocol (SSEP). METHODS: The motion characteristics of 12 first team members and 12 scholars (under 19s), signed to an English Premiership club were determined via motion analysis. Motion profiles from the analysis were then used to develop a SSEP for a non-motorised treadmill. Validity of the protocol was checked with 6, healthy, male soccer players who completed the SSEP and, on a separate occasion, a soccer match. Heart rates were recorded during both trials, in addition, capillary blood and expired air samples were taken, and RPE recorded, during the SSEP. RESULTS: Youth team players covered 10274+/-609 m, compared to 9741+/-882 m by the first team players (t=1.72, p>0.05; 95% CI for the difference = -1174 m to 109 m). The trend for greater mean distance covered by youth players could be attributed to the distances covered while jogging and running. Mean heart rate response was 166+/-9 beatsxmin(-1) during match play and 166+/-12 beatsxmin(-1) during the SSEP (t=0.164, p>0.05). Mean .VO(2) during the SSEP was 70+/-3% of .VO(2max). Blood lactate concentration fell from a mean value of 5.37+/-1.15 mmol x L(-1) during the first half to 4.74+/-1.25 mmol x L(-1) during the 2(nd) half (t=2.52, p