Background: 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.
Methods: 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.
Results: 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.
Conclusions: 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.