Physiology Lessons

Great article on running physiology (no kidding).  It answers all the nitty-gritty questions about VO2-max, Running Economy and Lactate Thresholds.  Very well written and easy to understand.  I especially enjoyed the last part about muscle types and how to focus your training.

Physiology Lessons (Trailrunner mag) (Jason R. Karp, Ph.D.)

Physiology Lessons (Running Times mag) (Jason R. Karp, Ph.D.)

Here's a quick synopsis:

How to Improve LT

• Continuous LT Run: Three to six miles at LT pace (for recreational runners, 10 to 15 seconds per mile slower than 5K race pace or about 10K race pace; for trained runners, 25 to 30 seconds per mile slower than 5K race pace or 15 to 20 seconds per mile slower than 10K race pace.)
• LT Intervals: 4 x 1 mile at LT pace with one-minute rest.
• LT-Plus Intervals: Two sets of 4 x 1000 meters at 10 seconds per mile faster than LT pace, with 45 seconds rest between intervals and two minutes rest between sets.

How to improve RE

• High mileage.
• Heavy strength training: Three to four sets of three to five reps with greater than 85-percent of your one-rep max 
• Plyometrics: Box jumps, squat jumps, leg bounds, bleacher hops, etc.

How to Train the Heart Muscle

• Run intervals close to one-mile race pace for recreational runners and two-mile race pace (10 to 15 seconds per mile faster than 5K race pace) for trained runners. You should be within a few beats of your maximum heart rate by the end of each interval. 
• Work periods should last three to five minutes and recovery periods (jog to keep oxygen consumption elevated) should be equal to or slightly less than the work periods.

How to Efficiently Train Enzyme Function

• Progressively increase your mileage each month. 
• Interval training (see "How to Train the Heart Muscle" above).

How to Efficiently Train According to Muscle-Fiber Type

• More ST fibers: Emphasize mileage and LT runs. 
• More FT fibers: Emphasize interval training

What's Your Fiber Type?

To determine your fiber type, you can either get a muscle biopsy or ask yourself the following questions:

• When you race,

(a) Are you able to hang with your competitors during the middle stages, but get out-kicked in the last quarter to half-mile?

(b) Do you have a hard time maintaining the pace during the middle stages, but can finish fast and out-kick others?

If you answered a, you have more ST fibers. If you answered b, you have more FT fibers.

• Which type of workouts feel easier and more natural?

(a) Long intervals (800-meter to mile repeats), long runs and tempo runs.

(b) Short, fast intervals (200s and 400s).

If you answered a, you have more ST fibers. If you answered b, you have more FT fibers.

• Which workouts do you look forward to more?

(a) Long intervals and tempo runs.

(b) Short, fast intervals.

If you answered a, you have more ST fibers. If you answered b, you have more FT fibers. (People tend to get excited about tasks at which they excel, while being more anxious about tasks that are difficult.)