Shuttle Run Performance
The shuttle run data revealed that subjects from BALANCE-HIIT (PRE: 87 ± 24 shuttles; POST: 96 ± 24 shuttles) and HIIT-BALANCE (PRE: 88 ± 20 shuttles; POST: 97 ± 16 shuttles) clearly improved their endurance capacity, whereas BALANCE showed nearly constant performance (PRE: 83 ± 37 shuttles; POST: 84 ± 35 shuttles). When comparing the training adaptations between the groups, the mixed linear model revealed higher gains with a small effect for HIIT-BALANCE and BALANCE-HIIT when compared with BALANCE (Table Average obtained from shuttle run performances in the PRE and POST assessments. Both groups that trained HIIT during the intervention increased the number of shuttles by approximately 12%, whereas the BALANCE group did not show relevant improvements (+3.6%). HIIT = high-intensity interval training.