2012 Northern California All-Sports Clinic
6
5 Lessons I Have Learned From
Physiology and How They Can Make
Your Athletes Faster Runners
© Jason Karp, Ph.D.
RunCoachJason.com
Founder/Coach, REVO2LT Running TeamTM
Freelance writer & author
2011 IDEA Personal Trainer of the Year
Lesson #1:
To run fast, distance runners must first
spend a lot of time running slow.
Above all else, it’s the volume of training that induces
the biological signal for adaptation and dictates the
performance capacity. To accomplish a large training
volume, runners must perform most of their running at
a relatively slow pace.
Aerobic running increases number of red blood cells &
hemoglobin, giving blood vessels greater oxygencarrying capability; increases muscle capillary volume,
providing more oxygen to muscles; & increases
mitochondrial volume & number of aerobic enzymes,
allowing for greater use of oxygen.
Lesson #2:
Lactate threshold and running economy
are more important than VO2max.
A high VO2max alone is not enough to attain elite-level
performances; it simply gains one access into the club,
since a runner cannot attain a high level of performance
without a high VO2max. While athletes can improve their
VO2max, it is largely genetically determined. The other
two major physiological players of distance running
performance—lactate threshold (LT) and running economy
(RE)—exert a greater influence on a runner’s performance
and are more responsive to training.
Lactate Threshold
• Slowest speed at which aerobic metabolism (Krebs
cycle & electron transport chain) can’t keep up with
production of pyruvate from glycolysis.
• Fastest speed above which lactate production begins
to exceed its removal, with blood lactate
concentration beginning to increase exponentially.
• Represents transition between running that is
almost purely aerobic & running that includes
significant oxygen-independent (anaerobic)
metabolism.
• Represents fastest speed that can be sustained
aerobically.
• Best physiological predictor of distance running
performance.
LT Pace
Slower, recreational runners:
~ 10-15 sec/mile slower than 5K race
pace (or ~ 10K race pace)
~ 75-80% max HR (~ 65-70% VO2max)
Highly trained/elite:
~ 25-30 sec/mile slower than 5K race
pace (or ~ 15-20 sec/mile slower than
10K race pace)
~ 90% max HR (~ 85-90% VO2max)
Subjectively feel “comfortably hard”
Types of LT Workouts
Continuous LT Runs
3-4 miles up to 7-8 miles for marathoners
LT Intervals
intervals @ LT pace with short rest periods
4 x 1 mile @ LT pace w/ 1 min rest
LT+ Intervals
short intervals @ slightly faster than LT pace with very short
rest periods
2 sets of 4 x 1,000 meters @ 10 sec/mile faster than LT pace
w/ 45 sec rest & 2 min rest between sets
LT/LSD Combo Run (for marathoners)
Long continuous runs with portion @ LT pace
12-16 miles w/ last 2-4 miles @ LT pace
2 miles + 3 miles @ LT pace + 6 miles + 3 miles @ LT pace
Running Economy
In 1930, David Dill & his colleagues at the
Harvard Fatigue Laboratory were among
the first physiologists to suggest that there
are marked differences in the amount of
O2 different people use when running at
the same speeds, and that these
differences in “economy” of O2 use is a
major factor explaining differences in
endurance performance.
Running Economy
If two people have same VO2max, but Jack
uses 70% & Martin uses 80% of that VO2max
while running at 7:00 pace, the run feels
easier for Jack because Jack is more
economical. Therefore, Jack can run at
faster speed before feeling same amount of
fatigue as Martin.
Running economy is the oxygen consumption
(VO2) used to maintain a specific running
speed.
Running Economy
• High mileage (>70 miles per week) seems to improve
running economy.
• optimized biomechanics
• hypertrophy of Type I skeletal muscle fibers
• greater skeletal muscle mitochondrial & capillary
volumes
• greater ability for tendons to store & utilize
elastic energy
• lower body mass
• optimized motor unit recruitment patterns gained
from countless repetitions of running movements
• Heavy strength training & plyometrics improve
economy, possibly by neural mechanism.
Lesson #3:
There are different muscle fiber types, which
reflect a runner’s strengths and weaknesses.
Slow-Twitch
Fast-Twitch A
Fast-Twitch B
Contraction time
Slow
Fast
Very Fast
Size of motor neuron
Small
Large
Very Large
Resistance to fatigue
High
Intermediate
Low
Aerobic
Long-term Anaerobic
Short-term Anaerobic
Force production
Low
High
Very High
Mitochondrial density
High
High
Low
Capillary density
High
Intermediate
Low
Oxidative capacity
High
High
Low
Glycolytic capacity
Low
High
High
Activity
What Are My Strengths/Weaknesses?
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 halfmile?
b) do you have a hard time maintaining the pace during the
middle stages, but can finish fast and out-kick others?
If a, more ST fibers; if b, more FT fibers.
Which type of workouts feel easier and more natural?
a) long intervals (800m-mile repeats), long runs, and tempo
runs
b) short, fast intervals (200-400m repeats)
If a, more ST fibers; if b, more FT fibers.
Which workouts do you look forward to more?
a) long intervals, long runs, and tempo runs
b) short, fast intervals
If a, more ST fibers; if b, more FT fibers.
Train to Your Strengths
• While improving an athlete’s weaknesses will
make him/her more successful, focusing on
his/her strengths will lead to best result.
Athlete’s training should always be skewed in
favor of what he/she is naturally good at.
• If endurance-type runner, best at longer
races; training should focus on aerobic work
(mileage & lactate threshold training).
• If speed-type runner, best at middle-distance
races; training should focus on interval
training.
Train to Your Strengths
If both runners train for same race:
• endurance-type runner should initially do longer
intervals, trying to get faster with training:
• 1,200-meter reps @ 5K race pace, increasing speed to
3K race pace or decreasing recovery as training
progresses
• speed-type runner should do shorter intervals,
trying to hold the pace for longer with training:
• 800-meter reps @ 3K race pace, increasing distance to
1,200 meters or increasing number of reps as training
progresses
• two paths to meet at same point
Lesson #4:
Metabolism is tightly regulated
by enzymes and oxygen.
The amount of an enzyme and the availability
of oxygen control which metabolic pathway
predominates. Enzymes essentially control
metabolism and therefore control the pace at
which you fatigue. Having more aerobic
enzymes steers metabolism toward a greater
reliance on aerobic metabolism at a given
speed. Training increases enzyme activity.
When pyruvate is converted
to lactate, metabolites
accumulate & acidosis
develops, causing muscles to
Lactate fatigue & pace to slow down.
Lesson #5:
A larger, stronger heart can pump more
blood and oxygen to your muscles.
Distance running is primarily limited by delivery & use
of oxygen, the former of which is dictated by the
amount of blood pumped by your heart per minute
(cardiac output).
Specific training can make the heart larger & increase
stroke volume & cardiac output. Work periods run at
speed at which VO2max occurs provide the heaviest
load on cardiovascular system because of repeated
attainment of maximum stroke volume & cardiac
output (and, by definition, VO2max).
VO2max Pace
Slower, recreational runners:
1- to 1½-mile race pace (near max HR)
Highly trained/elite:
~2-mile race pace (10-15 sec/mile faster than 5K
race pace; near max HR)
Examples of Workouts:
• 5-6 x 800 meters (~3 min) @ VO2max pace w/1:≤1
work-to-rest ratio
• 4-5 x 1,000 meters (~4 min) @ VO2max pace w/1:≤1
work-to-rest ratio
• 3 x 1,200 meters (~4½-5 min) @ VO2max pace
w/1:≤1 work-to-rest ratio
Work Periods
VO2max
(HRmax)
VO2
(HR)
Recovery Periods
Reps
Lesson #6:
Refueling immediately maximizes recovery.
Two important fuels to replenish after training are
carbohydrates & protein. Endurance performance is
strongly influenced by amount of muscle glycogen,
with intense endurance exercise decreasing muscle
glycogen content. Recovery is closely linked to
replenishment of carbohydrates, with glycogen
resynthesis most rapid if carbs are consumed
immediately after workout (0.7 gram of simple carbs
(e.g., glucose) per pound within 30 minutes & every 2
hours for 4-6 hours). Protein rebuilds skeletal muscle
fibers that have been damaged from training.