Optimization of fin-swim training for SCUBA divers

Underwater swimming is a unique exercise and its fitness is not accomplished by other types of training. This study compared high intensity intermittent fin-swim training (HIIT) with moderate intensity continuous (MICT). Divers (n = 20; age = 23 ± 4 yrs; weight = 82.57 ± 10.38 kg; height = 180 ± 6 cm) were assigned to MICT (65%-75% heart rate max (HRmax), for 45 min) or HIIT three 10 min swims/rest cycles (77%, 83%, and 92% HRmax, respectively) for 50 min. They trained using snorkel and fins at the surface paced by an underwater light system 3 times per week for 4 weeks. Swim tests were the energy cost of swimming, V _Q2max and timed endurance swim (at 70%V _O2max). The V _O2 was a non-significantly reduced at any velocity with either HIIT or MICT. Maximal swim velocity increased after HUT (10%) (p ≤ 0.05) but not after MICT (p > 0.05). V _O2 max increased 18% after HIIT and 6% after MICT (p ≤ 0.05). The endurance times increased 131%. after HIIT and 78% after MICT (p ≤ 0.05), and in spite of this post-swim lactate was not significantly different and averaged 4.69 ± 1.10mM (p > 0.05). Although both training methods significantly improved fin swimming performance with similar time commitments, the HIIT improved V _O2max and endurance more than MICT (p ≤ 0.05). As no improvements in ventilation were observed, combining HIIT with respiratory muscle training could optimize diver swim fitness.