Adaptations to sprint interval training and comparisons of gender response

Physical activity helps maintain health, promotes adaptations of the cardiovascular and neuromuscular systems to increase uptake, transport and utilisation of oxygen for aerobic energy production and improve fatty acid metabolism. Emerging evidence suggests sprint interval training (SIT) may be as effective as endurance exercise. The overall aim was to measure physiological effects of SIT in males and females from the general population. The first objective was to recruit males and females from the general population to complete 12 weeks cycling SIT and monitor changes relating to health and physiological function. The primary outcomes were changes in body fat mass, VO2max, FATmax, knee extensor muscle size, strength, power, fatigue resistance, circulating concentrations of lipoproteins and inflammatory markers. The secondary outcome was a comparison of results between males and females. The second objective was to recruit Masters sprint and endurance runners to complete measurements of health and physiological function. The primary outcomes were peak power output and VO2peak in one and two-leg cycling. After 12 weeks SIT, females showed higher increases (18.7%) in VO2max (ml/kg/min) than males (6%) (gender comparison: p=0.009), males exhibited greater body fat (%) reductions (1.5%) than females (0.1%) (gender comparison: p=0.015). Males and females had similar increases in knee extensor fatigue resistance (4.0% and 8.9% respectively, gender comparison: p=0.221) and muscle cross sectional area (CSA) (cm2) (4.1% and 5.8% respectively, gender comparison: p=0.895). Neither gender showed changes in circulating inflammatory proteins, but LDL decreased in males (7.8%) and females (3.7%) (gender comparison: p=0.161) and the ratio of cholesterol:HDL improved in females (13.1%) and males (19.6%) (gender comparison: p=0.523). Master sprint athletes had 22% higher peak power output (W/Kg) than endurance athletes (discipline difference: p=0.045), but endurance master athletes have 17% higher VO2peak (ml/kg/min) (p=0.012) and 30% higher FATmax (mg/kg/min) (discipline difference: p=0.041). The inverse relationship between VO2peak, FATmax and peak power with age was similar (10-12% per decade) for sprint and endurance athletes. It is concluded that males and females adapt positively to SIT, although gender differences in VO2max and changes to body fat were found. Despite differences between masters endurance and sprint athletes in FATmax, VO2peak and peak power, age related decline is similar in both disciplines