The effect of high intensity running training on work capacity in football (soccer)

Rationale: High Intensity Interval Training (HIIT) has been used by elite athletes for decades however, it is a relatively under researched training methodology in a team sport setting. Aim: The purpose of this study was to evaluate the effect of a high intensity interval training protocol on aerobic power and physical performance in competitive matches. Intervention: Twenty-five (25) players were recruited from a national Under 20 men's football (soccer) program. Players were randomly assigned to one of two intervention groups; - A high intensity interval training intervention group - A control group The intervention group completed a 10 minute interval training session, three times a week comprised of two sets of eight bouts of 15 second shuttles at approximately 120% of maximum aerobic speed, for a four week period. The control group performed a juggling exercise that was matched for time with the intervention group. Participants were not blinded to the intervention. Pre and post intervention testing involved physiological field testing including the Multi-stage Shuttle Test (MSST), vertical jump and 20 m sprint time. In addition, pre and post intervention match analysis data were derived from GPS devices. Three games were analysed pre and post intervention. Changes between the intervention and control groups, across the entire group from pre to post were analysed. Results: Results showed a significant improvement in the intervention group over the control group for aerobic power (p=0.0089), but no significant changes in vertical jump (p=0.3823) and 20 metre sprint time (p=0.0682). Match analyses from GPS data showed no differences between the groups for total distance, average distance covered per minute (meterage) and high intensity running variables. However, match analysis data when grouped for the all participants showed significant improvements in 1st III half meterage (p=0.0001), 2nd half meterage (p=0.001), 1st half versus 2nd half differences (p=0.001), 1st 15 minutes versus last 15 minutes meterage (p=0.026), high intensity running distance (p=0.001) and total high intensity running efforts (p=0.026) following comparisons of pre to post intervention data. Conclusion: Overall the study showed high intensity interval training based on a percentage of maximum aerobic speed during the season provided an effective means of improving aerobic power without negatively impacting on anaerobic performance. However, the absence of a significant transfer to match performance when compared with a control group may be due to multiple factors in elite junior development squads. The match data may also indicate that playing at a higher level than previously experienced may have had a positive effect on match performance for all participants. Transferring quantifiable training outcomes into match performances remains a challenge in team sports.