High-intensity Interval Training Shock Microcycle Improves Running Performance but not Economy in Female Soccer Players

This study aimed to evaluate the effect of high-intensity interval training shock microcycles (HIIT (SM) ) on endurance, running economy and change of direction economy in female soccer players. Nineteen sub-elite female soccer players were randomised to two groups: HIIT (SM) (10 HIIT sessions over 13 days) or HIIT (TRAD) (4 HIIT sessions over 13 days) interventions. Endurance performance was evaluated through the 30-15 intermittent fitness test (30-15 (IFT) ); running economy over a 5-min treadmill run; and change of direction economy over two conditions: (1) 5-min 20m shuttle run, and (2) 5-min 10m shuttle run. HIIT (SM) significantly improved 30-15 (IFT) scores compared to baseline (+4.4%, p=0.009; d =0.96) and 30-15 (IFT) scores relative to HIIT (TRAD) (p=0.002; d =2.01). There was no significant interaction (groupxtime) for running economy and change of direction economy. Pre- to post- intervention there was a significant main time effect for blood lactate over 20m and 10m shuttle runs (p<0.001 and p=0.037, respectively), with large ( d =0.93) an d moderate ( d =0.53) changes observed for the HIIT (SM) over the two distances, respectively. HIIT (SM) may be more effective than HIIT (TRAD) to improve 30-15 (IFT) over shorter training periods but may not affect running economy and change of direction economy.

Automated summary

This study found that high-intensity interval training shock microcycles (HIIT (SM)) significantly improved endurance and 30-15 intermittent fitness test (30-15 (IFT)) scores in female soccer players. However, HIIT (SM) may have a smaller impact on running economy and change of direction economy compared to traditional high-intensity interval training (HIIT (TRAD)).