I am very confused about weight training and running as I learn physics. When I run at 6 miles/hr (about 3 m/s) on treadmill for a minutes, I spend more than 10 calories. I believe these are food calories (KCal) so it is 10,000 cal or 10,000*4.18 Joules or approx 50,000 J ie 50KJ Ok so far so good. Now I lift 10Kg dumbbell 1 meter. Work Done = PE change = 10*9.8*1 = 98 Joules or say 100J Does it mean I have to lift it 500 times to burn same amount of calories as running for 1 min? I can easily run for a min but it is nearly impossible to lift 10kg 500 times so I know you need significantly more energy to lift weight than running. But the physics does not add up even after I account for all approximation, friction etc. What am I doing wrong?