The acceptable load while marching at a speed of 5 km h-1 for young Chinese males

Ninety-three young Chinese men selected at random were involved in the load carrying experiments. They marched at 5 km h-1 carrying loads of 0, 15, 20, 25 and 31 kg for 7 h per day. At this speed the acceptable load to be carried was 20 kg. Under this load 95% of the men had heart rates below 120 bt min-1 while marching and energy metabolism was in balance. Nevertheless, 10-15% of the men were fatigued and felt tired.