VERY LOW VOLUME HIGH INTENSITY INTERVAL EXERCISE: ACUTE EFFECTS ON PHYSIOLOGICAL AND PSYCHOLOGICAL STRESS IN YOUNG AND OLD WOMEN
Raulas Krušnauskas, Tomas Venckūnas, Audrius Sniečkus, Nerijus Eimantas, Neringa Baranauskienė, Sigitas Kamandulis – Lithuanian Sports University, Institute of Sports Science and Innovations, Kaunas
Introduction. High intensity interval training (HIIT) has been proposed as effective means to increase aerobic capacity and insulin sensitivity in adults of different age (Gibala et al., 2012). The main aim of this study was to investigate acute physiological and psychological stress in response to three types of very low volume HIIT session in young (19.5 ± 1.3 years) and old (65.7 ± 2.8 years) women.
Methods. Isometric maximal voluntary contraction (MVC) and 20 (P20) and 100 (P100) Hz electrical with stimulation induced knee extension peak torques were measured at baseline, and then immediately, 1 and 24 h after stationary cycling (either 6 × 5 or 3 × 30 all-out, or 3 × 60 sec submaximal efforts, each performed 5 weeks apart in the randomized order). In addition, lactate, IGF-1 and TNFα response was measured, and perceived exertion and preference for exercise type were assessed.
Results. Peak and average power were larger in young compared to old women and were largest during 6 × 5 strategy in both groups (p < 0.05). Both groups ranked 6 × 5 cycling as the most preferable for further training (90 %, p < 0.05). There was significant strategy and time interaction for P20 and P100 (p < 0.05). Strategy 6 × 5 did not change P100 in young, whereas in older group P100 was reduced only by 24 hours after 3 × 60 cycling (p < 0.05). P20/P100 ratio decline representing low frequency fatigue was more evident after 3 × 30 and 3 × 60 compared to 6 × 5 in both groups and was larger in young compared to old women (p < 0.05). Serum TNFα and IGF1 levels remained largely unchanged in both groups in response to any type of the three HIIT sessions.
Conclusions. Very low volume (6 × 5 s) all-out exercise induced long lasting (>24 h) low frequency force depression in young women. For aged women, longer exercise bouts (3 × 60 s) were more physiology stressful but still tolerable psychologically. These age related exercise strategy differences should be taken into account by practitioners when planning training program.
