The researchers of this study investigated the effectiveness of high intensity short interval training on skeletal muscle mass and cardiovascular function in untrained 50- to 68-year-old participants (Allen JR, et al.,2021).
The research lasted for 8 weeks, and each session involved 15-30 sprints on a stationary bike 3 times per week. Each sprint lasted only 4 seconds.
After 8 weeks the thigh muscle volume had increased by 3.7%, Pmax (power output) by 12% and peak oxygen consumption by 9.8%. The cardio-ankle vascular index was significantly decreased by 2.3% indicating reduced arterial stiffness.
The reserchers concluded that these results demonstrate that 8 weeks doing this type of high intensity short interval training at true maximal power was effective at increasing muscle mass and maximal power, as well as maximal cardiovascular capacity and functional tasks in untrained 50 to 68 year old individuals.
Reference
Allen JR, Satiroglu R, Fico B, Tanaka H, Vardarli E, Luci JJ, Coyle EF, Inertial Load Power Cycling Training Increases Muscle Mass and Aerobic Power in Older Adults. Med Sci Sports Exerc. 2021 Jun 1;53(6):1188-1193.