"... am I expending more, less, or the same amount of energy each time ..."
First of all, reading a little more into your question -
If you are asking about Work-
it's Mass over Distance - and Work stays the same. Same mass, same distance.
If you really are asking about Energy it gets a lot more complex. Your physiology comes into play, and the answer is "More".
People aren't efficient and straightforward about converting energy into work. A large amount of calories expended go into heat (just like an incandescent light bulb). As effort goes up utilization, and efficiency, may go down.
Depending on output level, our energy source may change from one metabolic source to another, which may affect your overall efficiency. Some people (elite athletes) maintain their efficiency during very high levels of output. Others, not so much.
And as Greg G. mentions, we may become less efficient mechanically just due to the difference in the mechanics of our stride, arm swing, posture, etc., which means more energy is needed.
p.s. Not an expert in Any field.