Question

If a 70 kg athlete climbs 0.8 metres up a ladder in one second, can I interpret this as:
Potential energy = mgh where m is 70 kg and 0.8 metres represents the height h, thus: Potential energy = 70 x 9.81 x 0.8 = 549 joules.
Can I then substitute this energy into the kinetic energy formula in order to find what speed he can run after one second, thus:

Kinetic energy = 0.5mv^2 = 549 joules.

Whereupon
v^2 = 549/(0.5 x 70) = 15.69.
Making v = 3.96 m/sec
after one second?
Am I correct?