A repeated theme in the book is that you don't necessarily have to be the smartest/strongest/whateverest but you do have to be smart enough, strong enough or whatever enough, and then you have to have the right environment in order to succeed. You don't have to be seven feet tall to play in the NBA, but you do have to likely be at least six-two. Six two is the threshold (I just made that number up, don't have the book anymore, but I imagine you get the idea). So, for different mountain sports, what are the thresholds that mean "good enough?"
To start with, I believe that performance is the acid test of any training program. We all choose to train three main performance components (our skill, muscles, and head); how we perform is the test. An athlete's performance will generally depend not on which one of these three are the strongest, but which one is the weakest. The absolute strongest athlete often doesn't win a climbing competition; the guy or girl with adequate strength and excellent skill combined with a strong competition head usually wins. We all know climbing gym monsters who can't lead 5.10 on real rock. They don't have the skill or head part. But, and this is the almost funny part, the easiest things to train are muscles, so that's where most people focus most of their time while trying to get "better" at a mountain sport. I really believe this physical-centered approach is wrong for most athletes in the mountain sports I know.
In my experience the fastest performance gains for athletes are usually made when they train their sport-specific weaknesses, specifically skills. I try to get the athletes I work with to attack what they are worst at first; many times that means reading sports psych books, or changing their training to reflect competition stress, or some other aspect beyond just moving things around physically. But, and it's a big butt, if they don't have Gladwell's "Threshold" strength then they will also need that. Any athlete can also use a fully functional body, and a general physical prep program is good for that. A GPP approach is also great for athletes who switch sports around a lot, as I tend to do.
So what are threshold strength levels for a few different mountain sports?
With zero scientific methodology I'd offer the following threshold strength levels for what I would call a "solid" level in each sport:
-Hike up 3,000 feet in under one hour, 5,000 feet in under three (Messner could reportedly do 1,000M/3,200 feet in under 30 minutes or something...).
-Do 10 pullups (not because pullups are necessary, but because anyone who can do 10 real pullups is sorta trained up)
-Do "Angie" in under 20 minutes if you think you're "elite."
-Climb grade IV ice all day on minimal gear and be relaxed about it, lead 5.6 with a pack.
Technical rock climbing at a solid 5.13 level
-Do 10 pullups on a half-inch ledge.
-Hang a 1 inch ledge for 5-10 seconds one-handed.
-Campus up the smallest rungs in your climbing gym.
-Climb ten 30M pitches of modern mid-5.12 a in a day (all different pitches, no laps).
Trad Rock climbing 5.10:
-Do one pullup on a one-inch rung.
-Do three pullups on a bar.
-Hike 1,000 feet vertical in 30 minutes.
-Climb all day on 5.7 and still think it's fun.
Kayak class V and up with physical reserves:
-Mountain bike for an hour straight without having to stop and gasp.
-Row 2K in under 10 minutes.
-Bench their own weight.
-Play anywhere in a class IV run.
Mixed climbing M12 (without trickery):
-Ten pullups with tools staggered lower head to upper spike.
-Front lever for two seconds, 20 knees to elbows straight.
-One-handed hang 20 seconds, 20 seconds other hand, repeat for ten cycles.
-Onsight M10 sometimes, always do it second try.
-Gain 3,000 feet in under one hour even after smoking up.
There are definitely people who will be able to meet the technical standard without having the threshold strength, but by and large these are the physical standards I think are required if an athlete is to be at a roughly equal personal level (strength, skill, head). Chances are that if you have these strengths then you can get the day's job done at that standard. If a kayaker can't bench his or her own weight then they are paddling without a physical reserve and are relying instead on reserves of skill and headspace. I see physically strong paddlers get bit off because they lack skill and headspace more than I see skilled but relatively weak paddlers get into trouble, but I see both regularly. Often the paddler doesn't know he or she is weak or has lost skill... A paddler who is strong in all ways is better than one who lacks in one area, and one day that raw strength is going to really, really count.
But I also put a sort of "skill and head check" in each list; many people claim to want to climb 5.13, but can't climb ten pitches of mid-5.12 in a day. They can likely siege a 5.13 into submission if they have the threshold strength, but they won't be doing a new 5.13b in a day with regularity (and that's what climbing at that grade means to me for the purposes of this discussion). I know a few "alpinists" who can hike up hill like mad, but can't lead basic water ice smoothly... They will not succeed on major winter alpine objectives without a basic skill set.
So, are you strong enough, skilled enough, and mentally together enough to actually perform at the level you want to? And if not, why not? This is where it gets interesting, and self-examination becomes more important than another set of squats. Which may also help, but if you're at double or triple the threshold strength for what you want to do and still not getting it done then perhaps it's time to try something different. Immediately. And if you're not at threshold strength then you're very late for a training session.
This stuff is really fun to think about, especially as I work through my own goals, limitations and successes with my own sports and training.