[Scott Johnston]

Great question.  I suspect that during the down-hiking 30-40sec each lap, your HR does not drop more than 5-10 beats, which will still keep you in Z2 even though the down portions are loading the muscles eccentrically and the up bits are loading concentrically.  So there will be some difference in training effect when compared to, say, spending 2 hours going up only on a Stairmaster.   I’d add in one Stairmaster session a week.  All that downhill that the stadium gives you is going to be very useful for going downhill in the mountains.

Keep up this training, and you will be a beast in the mountains.

Scott