Presentation part 3 of 4 from Dr. Ernie Maglischo as part of the SwimISCA.org workshop with the Eastern States Clinic in King of Prussia, PA.

1. HIT and USRPT
Training

2. The order of contraction for fast and slow
twitch muscle fibers.
Figure 1.26. The order of contraction for the three basic muscle fiber types. The first type of muscle fibers to be recruited are the slow
twitch because they have the lowest threshold for stimulation. The Fta motor units have a higher threshold for excitation Therefore, they
require a stronger stimulus before they will contract. FTx motor units require the strongest stimulation before they will contract. Thus,
when the intensity of exercise is low, nervous stimulation will also be low, and only the motor units containing ST muscle fibers will
contract. When exercise intensity increases, so will the nervous stimulation. Therefore, the FTa motor units will also contract. The Ftx
motor units will not contract until exercise intensity is high. Therefore they will not be recruited until the exercise intensity is very high.
This drawing was reprinted from: D.W. Edgerton, and V.R. Edgerton. (1976). The Biology of Physical Activity. p. 53.
Boston, MA.: Hughton-Mifflin.

3. The “ramp” effect of muscle fiber recruitment
during exercise
Aer Th
ST
VO2 max
ST = 50%
FTa = 30%
FTx = 20%
FTa
FTx
Lactate
Th
The “ramp” effect of muscle fiber recruitment during exercise. Muscle fiber types are recruited according to the intensity of work. At low intensities,
ST muscle fibers will be recruited. At higher intensities that includes a significant amount of anaerobic metabolism, the Fta muscle fibers will also
be brought into the activity. And, at very high levels of work intensity, the FTx fibers will be brought into the mix. Adapted with permission from:
J.H. Wilmore and D.L Costill. (2004). Physiology of Sport and Exercise. p. 50. Champaign, IL: Human Kinetics,
%
of
maximum
speed

4. HIT Training
Training groups Training
Programs
VO2max Anaerobic
Capacity
Traditional
Group
Cycling at 70%
VO2max for 60 mins.
daily, 5 days/week
for 6 weeks
Increased 10% No Change
Hi-Intensity
Group
8 x 20 sec. sprints
With 10 secs. rest
between at 170%
VO2max., 5 days/wk
for 6 weeks.
Increased 14% Increased 28%
Data from: “Effect of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and
VO2max.. “I. Tabata, K. Nishimura, M. Kouzaki, Y. Hirai, F. Ogita, M. Miyachi, and K. Yamamoto, (1996), Medicine &
Science in Sports & Exercise, 28(10): 1327-1330.

5. All muscle fibers must be recruited to improve
VO2max as much as possible
This graph represents my attempt to demonstrate that aerobic capacity, expressed as VO2max ,cannot be improved
unless the aerobic capacity of all three fiber types of muscle fibers are increased maximally. Improving the aerobic capacity of fast twitch muscle fibers
requires that athletes train at speeds that are faster than anaerobic threshold and VO2max velocities for long periods of time.
Fast Twitch x
= 15%
Fast Twitch a
= 30% Slow Twitch
= 55%

6. Why USRPT and HIT training
work.
1. Both allow athletes to swim at race speed or
faster without producing excessive fatigue.
2. USRPT training, in particular, allows athletes to
swim more yardage at race speed without creating
significant acidosis, or whatever it is that causes
muscle fatigue.
3. It is a very specific way to improve the aerobic
capacity of fast twitch muscle fibers, perhaps with
less damage to those fibers.

7. Metabolism during 3 x 30 sec cycling sprints with 4 mins
rest between
0
20
40
60
80
100
Aerobic Met
Anaerobic Glyc.
PCr
Figure 6.4. The energy contribution of aerobic metabolism, anaerobic glycolysis, and creatine phosphate (PCr) after 3,
30 second sprints on a bicycle ergometer with 4 minutes of rest between them. Adapted with permission from:
Parolin, et al., (1999). Regulation of skeletal muscle glycogen phosphorylase and PDH ( pyruvate dehydrogenase) during
maximal intermittent exercise. American J. of Physiol. 277: E890-E900.
1 3

8. Contributions from various energy sources
during 16 x 6 sec sprints on 1:30
Sprint #1 Sprint #16
ATP
PCr
Anaerobic
glycolysis
Aerobic
metabolism
6%
40%
46%
2%
40%
49%
9%
Figure 7.4. The contributions from ATP, creatine phosphate, anaerobic glycolysis and aerobic metabolism to the energy required to
perform 16, 6 second sprints on a send-off of 1:30. You can see here, how much the energy contribution from aerobic metabolism
increased and the contribution from anaerobic metabolism decreased between the 1st. And 16th. repeats. Adapted with permission
from: D. Bishop, ( 2009). Ergogenic aids and fatigue during multiple sprint exercise. In: C. Williams and S. Ratel, (Eds.) Human
Muscle Fatigue, p. 212. New York, N.Y.: Routledge,
8%

9. Contributions from various energy sources during 2
all out 30 sec maximal cycling efforts with 4 mins.
rest between.
Sprint #2
ATP
PCr
Anaerobic
metabolism
Aerobic
metabolism
Sprint #1
25% slower
20%
36%
43%
1%
29% 19%
48%
4%
Figure 7.6. The contribution for ATP, CP, anaerobic glycolysis and aerobic metabolism to the energy for 2, 30 second maximal
repeats on a bicycle ergometer. Adapted with permission from: Bogdanis, et al., 1996. Contributions of phosphocreatine
and aerobic metabolism to energy supply during repeated sprint exercise. J. of Appl. Physiol., 80: 876-884

10. HIT and USRPT training will improve endurance
(Aerobic Capacity)
A large amount of mileage can be done without acidosis
occurring. Very good for increasing the mitochondria
of fast twitch muscle fibers.
Perhaps, most importantly for sprinters and
middle distance swimmers, the repeats can be done
at race pace and faster. This is excellent for training
swimmers to stroke properly at race speed and to
hold their strokes together when tired. Also, excellent
for improving the lactate shuttle mechanism for middle
distance and distance swimmers.

11. The Lactate Shuttle
Fast twitch fiber
Slow twitch fiber
Mitochondrion
Lactate + H+ + MCT-1
Glycogen
Lactate + H+ + MCT-1 Pyruvate
Vein
Capillary
Liver Heart
Lactate + H+ + MCT-4
Pathways for removing lactate and H+ from working muscle fibers during exercise. 1. Lactate and H+ can
enter the mitochondria of muscle fibers where they were produced and be metabolized aerobically. 2. They can be transported to
adjacent fibers, enter the mitochondria of those fibers, and be metabolized aerobically. They can enter the capillaries and be carried
to other muscle fibers , the liver, and the heart, where they can be metabolized or, in the case of the cardiac fibers, used for energy.

12. The effect of training on lactate removal from
working muscles during exercise.
Figure 4.18. The effect of training on lactate removal from working muscles during exercise. The graph was drawn
from data in: C.M, Donovan & M.J. Pagliassotti. 1990. Enhanced efficiency of lactate removal after endurance
training. J. Appl. Physiol. 68(3):1053-1058.
Blood lactate in mmols/l
0 2 4 6 8 10 12
150
100
50
0
Control Group
Trained Group
200
Lactate
Removal
rate

13. A reason why USRPT and HIT training may not work as well
as traditional endurance training for improving the aerobic
capacity of middle distance and distance swimmers
Davies, Packer, and Brooks, (1981). Davies, K.J., Packer, A.L., and Brooks, G.A. (1981). Biochemical adaptation of mitochondria, , muscle,
and whole-animal respiration to endurance training. Archives of Biochemistry and Biophysiology, 209: 539-554.
Trained 20 rats on a rat-treadmill for 10 weeks at 80% of VO2max .
VO2max increased, on average 14%,
Mitochondria increased by 100% (range 63% to 138%).
Increased running time to exhaustion by 403%
(183 mins post-training versus 36 min. pre-training.)
Relationship between VO2 max and performance was 0.72 while
It was 0.92 for mitochondrial density and performance, suggesting
that an increase of mitochondria had a greater influence on time to exhaustion than
an increase of VO2max.
Therefore, according to these researchers, “It is appropriate to propose mitochondria
metabolism as a determining factor for endurance and not VO2max.”
(paraphrased from the original).

14. Why USRPT and HIT training may not
work as well as traditional endurance
training
Neither USRPT nor HIT training provides an
adequate stimulus for increasing the aerobic
capacity of slow twitch muscle fibers.
The aerobic capacity of slow twitch muscle fibers
can probably be improved best by increasing
training volume at moderate speeds.
Neither USRPT and HIT Training may improve the
aerobic capacity of Fta fibers to the same extent as
training near Anaerobic Threshold speeds once
those fibers become well-trained.

15. Abstract-ID: 2876: D. Bishop, (2015) Can we optimize the exercise training
prescription to maximize improvements in mitochondria function and content?
First conference on Endurance in Sports, Univ. of Kent, UK.
Purpose: Determining the optimal training stimulus to
maximize improvements in mitochondrial biogenesis. . .”
A survey of the literature concerning results with humans
and rats shows:
Findings:
1. Training intensity is an important factor in
mitochondrial respiration but not mitochondrial density.
2. On the other hand, there are indications that
training volume rather than intensity may be more
important for increasing mitochondrial density.

16. Distance Training Models
Low Volume/High Intensity. (HIT) (USRPT)
High Volume/Low intensity
Anaerobic Threshold training
Polarized. (No middle, Low intensity or high
intensity)
Pyramid. (Descending sets)

18. Table 6.2. The effect of training at various intensities on increases in
the activity of enzyme markers for aerobic capacity in rats.
Training
speeds in
m/min
10/11 20/22 30 40/44 50 60
VO2max
equivalent 62-63% 73-75% 80-85% 100% 105% 116%
Slow twitch
fibers +17-30% +23-30% +39% +39-42% +15% +7%
FOG
fibers +21-33% +36-40% +47% +47-52% +42% +47%
FG
fibers +0-13% +0-29% +47% +48-80% +90% +180%
Running time
To
exhaustion
127 mins 314 mins 569 mins
1. Influence of exercise intensity and duration on biochemical adaptation in
rat skeletal muscle. Dudley, Abraham and Terjung, (1982)
J. of Appl Physiology 53(4): 840-850.
2. Harms and Hickson, (1983) Skeletal muscle mitochondria, endurance and
Intensity of training. J of Appl Physiology. 54(3): 798-802.

19. Peripheral and Central Training
adaptations that can be produced by
training at moderate intensity
Peripheral training adaptations:
Increased capillarization around slow twitch muscle fibers.
Increased myoglobin in slow twitch muscle fibers.
Increased mitochondria in slow twitch muscle fibers
Increased glycogen storage in slow twitch muscle fibers.
Increased creatine phosphate and ATP storage in slow twitch muscle fibers.
Increased fat metabolism in both muscle fiber types if volume is great enough
.
Central training adaptations:
Increased pulmonary diffusing capacity
Increased stroke volume and cardiac output.
Increased capillarization in the lungs.
Increased vital capacity and other lung volumes.
Improved blood shunting
Increased blood volume and hemoglobin
Improved lactate shuttle if intensity is great enough to also stimulate FT muscle fibers (but not so intense as
to cause early fatigue).
Figure 7.22. Peripheral and central training adaptations that can be produced by training in the
Slow-twitch fiber zone (En-1) E.W. Maglischo 2015. A primer for swimming coaches, Vol. 1

20. Table 8.1. Test Results for Traditional compared to Reverse Periodization.
Tests T1 T2 T3 T4 T5 %Change
T1 to T5
100 tt 61.6 61.3 61.2 61.2 61.3 -0.4%
Stroke Rate 45 47 46 46 46 +2.9%
Stroke
Length
1.37m 1.31m 1.32m 1.32m 1.33m -3.0%
Power 43.2w 39.2w 44.8w 45.4w 45.7w +5.7%
100tt 62.7 60.9 59.1 58.6 58.6 -6/9%
Stroke Rate 49 48 48 50 47 -3.9%
Stroke
Length
1.28m 1.28m 1.23m 1.18m 1.25m -2.4%
Power 41w 40.6w 46w 47.6w 49.6w +20.9%
Data were taken from: J.J. Arroyo-Toledo, et al., (2013). Comparison between
Traditional and Reverse Periodization: Swimming Performance and Specific Strength
Values. International Journal of Swimming Kinetics, 2(1): 87-96.
Training
Group
Traditional
Perodization
Reverse
Perodization

21. The “ramp” effect of muscle fiber recruitment
during exercise
Aer Th
ST
VO2 max
ST = 50%
FTa = 30%
FTx = 20%
FTa
FTx
Lactate
Th
The “ramp” effect of muscle fiber recruitment during exercise. Muscle fiber types are recruited according to the intensity of work. At low intensities,
ST muscle fibers will be recruited. At higher intensities that includes a significant amount of anaerobic metabolism, the Fta muscle fibers will also
be brought into the activity. And, at very high levels of work intensity, the FTx fibers will be brought into the mix. Adapted with permission from:
J.H. Wilmore and D.L Costill. (2004). Physiology of Sport and Exercise. p. 50. Champaign, IL: Human Kinetics,
%
of
maximum
speed