"Muscle atrophy training"??

[Yelsel]

Yes -- fast twitch muscle fibers are better able to grow in size (hypertrophy). That is one aspect of strength.

Strength also includes:
Increased muscle cell recruitment; nerves recruiting more muscle cell bundles and more nerves firing.

Increasing tendon strength -- this is one of the most important -- your tendons have built-in strain sensors (golgi apparatus). Your brain will limit muscle movement to match tendon strength. In times of dire need, such as a car crushing your spouse, you can override this limit -- even a tiny out-of-shape person has the potential strength to lift a car or telephone pole. The price is really messing up your tendons and muscles, though.

Increased lactate threshold; more blood vessels, more mitochondria.

Increased storage of glycogen, creatine (creatine phosphate is the energy system used for sprints at 90%+ heart rate).

More into endurance, but the body gets more efficient at using fatty acids for fuel (higher fat / glycogen percentage) - to preserve glycogen stores.

Strength Training
for strength: 3 sets of 4-6 reps to failure (increases fast and slow twitch without a lot of muscle mass increase)
for hypertrophy: 5-6 sets of 8-12 reps to failure (muscle mass increase, fast twitch strength increased)
for endurance: 4 sets of 12-15 reps to failure (slow twitch strength increased, no muscle increase)
rest muscles for 24 hours before training again - muscles heal.
rest week (1/2 intensity) every 4-6 weeks - nerves, tendons, bones heal.
Cycling weight training usually recommends endurance lifting, I prefer strength lifting. But I love lifting as much as biking -- and it fits well together seasonally -- so I am willing to increase muscle mass too.

Plus with the new research on calcium loss in cyclists leading to osteoperosis greater than in sedentary people... doing strength sets to build up bone seems like an even better idea. (Eating more calcium is tricky - too much and you start calcifying your arteries.)