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Old 02-28-2009, 02:01 PM   #12
Donald Lee
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Join Date: Mar 2008
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Explosive Lifting for Muscle Growth

by

Robbie J.Durand

According to a study published in the European Journal of Applied
Physiology, lowering the weight slowly may not be the best way to
increase muscle mass and strength. In that study, male and female
subjects were assigned to train for 10 weeks to either two types of
training: slow or fast velocity eccentric training. At the end of the
study, the group that trained with fast eccentric contractions had the
greatest increase in muscle hypertrophy. Muscle hypertrophy of the
type IIB fibers (i.e. type IIB fibers are fast twitch fibers)
increased from 6% to 13% in subjects. The slow group did not
experience any gain in muscle mass (1).

Farthing et al. (25) reported similar finding in that fast eccentric
lowering was superior to slow eccentric lowering. Men and women
trained the same number of reps and sets but the only difference was
the speed at which they performed the reps. The fast eccentric
lowering group increased muscle hypertrophy by 13% whereas the slow
eccentric group increased muscle hypertrophy by 7.8%.

In a follow up study by Farthing and colleagues, compared fast and
slow training, a group of 12 untrained men exercised both arms three
days per week for eight weeks (2). The men trained one arm using a
fast velocity, while they did the same number of repetitions for the
other arm at a slow velocity. At the end of the study, Type I muscle
fibers increased in size by an average of 9% with no significant
differences between fast or slow training. The change in fiber area
after training for the type II fibers was greater in the fast-trained
versus the slow-trained arm. In addition to greater increases in type
IIb fibers, the fast eccentric contractions group increased strength
to a greater extent than slow contractions.

However, incorporating plyometrics and other explosive lifts may cause
additional muscle growth of IIb fibers. For example, there have been
numerous studies that have documented increases in type IIb fibers
after explosive weight training (8, 9) and plyometrics (10, 11). For
example, when male subjects performed plyometric training for three
days a week for eight weeks resulted in significant increases in type
IIb fiber hypertrophy and peak power production. The plyometric
training consisted of vertical jumping, bounding, and depth jumping (22)

Hortobagyi et al. (20) had 15 males train either isokinetically CON or
ECC for 12 weeks. Each subject trained with 4-6 sets of 8-12 reps; 3
times a week. At the end of 12 weeks, Type I fibers did not increase
significantly in either group. The most interesting aspect of the
study was that Type II fiber area increased 10 times more in the ECC
group compared to the CON group.

Contrary to CON training, acute ECC training resulted in a
significantly higher protein synthesis rate 58% compared to 38%. Post-
exercise protein synthesis rates from ECC but not CON exercise
resulted in increased protein synthesis rates for 36-41 hours after
exercise. ECC exercise produced muscle hypertrophy, whereas the
similar CON protocol failed to produce muscle hypertrophy. Protein
synthesis increased in the tibialis anterior (TA) after as little as 1
minute of total contraction duration (24 repetitions) by 30% and 8
minutes of total contraction time (192 repetitions) further increased
TA protein synthesis by 45% above controls.

Additionally, it has been reported that type II b fibers are more
susceptible to eccentric exercise induced muscle damage than type I
fibers, which may explain how fast ECC contractions induce muscle
hypertrophy (23). The greater force producing capacity and higher
degree of muscle damage can stimulate hypertrophy thru numerous
mechanisms.

References

1. Paddon-Jones D, Leveritt M, Lonergan A, Abernethy P. Adaptation to
chronic eccentric exercise in humans: the influence of contraction
velocity. Eur J Appl Physiol. 2001 Sep;85(5):466-71.

2. Farthing JP, Chilibeck PD. The effect of eccentric training at
different velocities on cross-education. Eur J Appl Physiol. 2003 Aug;
89(6):570-7.

8. Hakkinen K, Pakarinen A, Kraemer WJ, Hakkinen A, Valkeinen H, Alen
M. Selective muscle hypertrophy, changes in EMG and force, and serum
hormones during strength training in older women. J Appl Physiol. 2001
Aug;91(2):569-80.

9. Hakkinen K, Kraemer WJ, Newton RU, Alen M. Changes in
electromyographic activity, muscle fibre and force production
characteristics during heavy resistance/power strength training in
middle-aged and older men and women. Acta Physiol Scand. 2001 Jan;
171(1):51-62.

10. LaStayo PC, Woolf JM, Lewek MD, Snyder-Mackler L, Reich T,
Lindstedt SL. Eccentric muscle contractions: their contribution to
injury, prevention, rehabilitation, and sport. J Orthop Sports Phys
Ther. 2003 Oct;33(10):557-71.

11. Lindstedt SL, Reich TE, Keim P, LaStayo PC. Do muscles function as
adaptable locomotor springs?J Exp Biol. 2002 Aug;205(Pt 15):2211-6.

14 missing

15. Wong, T.S., and Booth, F.W. Protein metabolism in rat tibialis
anterior muscle after chronic eccentric exercise. J. Appl. Physiol.
69:1718-1724, 1990b.

20. Hortobagyi, T., Dempsey, L., Fraser, D., Zheng, D., Hamilton, G.,
Lambert, J., and Dohm, L. Changes in muscle strength, muscle fibre
size and myofibrillar gene expression after immobilization and
retraining in humans. The Journal of Physiology. 524.1, pp. 293-304,
2000.

22. Potteiger, J.A., Lockwood, R.H., Haub,M.D., Dolezal, B.A.,
Almuzaini,K.S., Schroeder,J.M., Zebas,C.J. Muscle Power and Fiber
Characteristics Following 8 Weeks of Plyometric Training The Journal
of Strength and Conditioning Research. Volume 13, Number 3, 275-279,
1999.

23. Friden J. Changes in human skeletal muscle induced by long-term
eccentric exercise. Cell Tissue Res. 1984;236(2):365-72.

25. Farthing JP, Chilibeck PD. The effects of eccentric and concentric
training at different velocities on muscle hypertrophy. Eur J Appl
Physiol. 2003 Aug;89(6):578-86.
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