Running economy and energy cost of running with backpacks.

Abstract

Running is a popular recreational activity and additional weight is often carried in backpacks on longer runs. Our aim was to examine running economy and other physiological parameters while running with a 1-kg and 3-kg backpack at different submaximal running velocities. Ten male recreational runners (age 25±4.2 years, VO2peak 60.5±3.1 mL/kg/min) performed runs on a motorized treadmill of 5 minutes durations at three different submaximal speeds of 70, 80 and 90% of anaerobic lactate threshold (LT) without additional weight, and carrying a 1-kg and 3-kg backpack. Oxygen consumption, heart rate, lactate and RPE were measured and analyzed. Oxygen consumption, energy cost of running and heart rate increased significantly while running with a backpack weighing 3 kg compared to running without additional weight at 80% of speed at lactate threshold (sLT) (P=0.026, P=0.009 and P=0.003) and at 90% sLT (P<0.001, P=0.001, and P=0.001). Running with a 1-kg backpack showed a significant increase in heart rate at 80% sLT (P=0.008) and a significant increase in oxygen consumption and heart rate at 90% sLT (P=0.045 and P=0.007) compared to running without additional weight. Also running at 70% sLT running economy and cardiovascular effort increased with weighted backpack running compared to running without additional weight, however these increases did not reach statistical significance. Running economy deteriorates and cardiovascular effort increases while running with additional backpack weight especially at higher submaximal running speeds. Backpack weight should therefore be kept to a minimum.