Hi, a caution to fellow >50 year olds on the hill sprints. I bought Training for the New Alpinism and followed the program to create a big aerobic base. Then I moved to max strength and chose hill sprints as my primary approach. Well, despite a good warm up, I pulled a hamstring — just grade 1 — and struggled the next month to try to ice it, rest it, and move on to weight hill climbs since my trip to Rainier was only 2 months away. I just had to cancel. So if you’re >50 and not very flexible, I would recommend finding some way other than hill sprints to achieve max strength.