Abstract:
Two experiments were undertaken to develop a high intensity intermittent training (HIIT) program for varsity football players. The aim of study 1 was to establish an optimal HIIT program based on measured physiological responses. Twelve male university soccer players age ranged 18-22 yrs with maximum oxygen consumption (VO2max) greater than 51 ml/min/kg were recruited to participate in the study. Participants completed 3 different HIIT protocols in a randomized crossover order. Heart rate (HR) was continuously measured before and after each HIIT training protocol. Gas exchange and fingertip blood lactate (BLa) were also collected before each HIIT program and at 0, 3, 6, 9, 12 and 15 minutes post exercise. A one-way repeated measures ANOVA was applied to examine significant differences between each measured variable and a Tukeys post hoc test was employed. The results showed that both BLa concentrations and rate of BLa clearance were significantly greater in program I compared with program II and III, respectively (p<0.05). It was concluded that the HIIT program I induced similar physiological demands to varsity football competition. In study 2, the addition of a HIIT program (established in study 1) to routine training on anaerobic performance and specific fitness in varsity football players was investigated. Thirty-two males from Mahidol University football team aged 18-22 yrs with VO2max greater than 51 ml/min/kg were recruited to participate in the study were recruited to participate in the study. Participants were randomly allocated into 2 groups; HIIT (n=16) and control group (n=16). In the HIIT group, participants performed a routine training program with the addition of 25-min of HIIT, 3 days per week for 6 weeks (total 18 sessions). In the control group, participants performed only their regular training program. Anaerobic power, anaerobic capacity, repeated sprint ability, strength, speed, agility, rate of force development and BLa were measured before and after 6 weeks of training. The data were analyzed using an one-way multivariate analysis of variance to determine the interaction of different intervention groups and time courses at significant level of p<0.05. It was found that anaerobic power, anaerobic capacity and repeated sprint ability were greater in the HIIT group compared with the control group after six weeks of training. However, there were no significant differences in strength, speed, agility, rate of force development and BLa accumulation levels between the two groups. Moreover, there was no significant difference in VO2max between two groups. These results suggest that the addition of a HIIT program to regular training enhances anaerobic performance due to neuromuscular adaptation; especially in fast-twitch muscle fibers (type II). Therefore, the addition of HIIT to a regular training program is able to improve anaerobic performance and optimize performance in varsity football players after 6 weeks of training.