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Researched and
composed by Eamonn Flanagan, BSc., CSCS
Published August 31, 2006
The annual conference of
the International Society of Biomechanics in Sports (ISBS)
was this year hosted in the beautiful setting of
Salzburg in
Austria. Having attended the conference last year in Beijing, China I was hugely
looking forward to a conference which very successfully combines presentations
of the latest in biomechanics research with very enjoyable social events.
This year,
the conference was comprised of
7 keynote lectures, 22
applied symposia lectures, 140 oral presentations and 105 poster presentations.
This year keynote lectures were delivered by: Darren
Stefanyshyn, Jan Cabri, Alberto Minetti, Felix Eckstein, Vasilios
Baltzopoulos, Bruce Elliot and Joseph Hamill. Joseph
Hamill of the
University
of Massachusetts was honored by the society this year with the prestigious
Jeffrey Dyson award. His detailed presentation outlined the role of complex
biomechanical analyses in understanding the mechanism of injury in overuse
running injuries.
This year
the structure of the conference was a little different to that in Beijing last
year. This year along with the usual keynote lectures, there were also a number
of applied symposia where invited speakers were afforded opportunities to
discuss their specific research interest in a dedicated, specialized symposium.
For example, there were applied symposia on skiing, footwear, tennis, football
(soccer) and strength training.
Obviously
that of strength training warranted specific attention from me. Two
presentations here were of particular interest and these will be discussed
briefly in this article.
The first
was by Dietmar Schmidtbleicher who also chaired the strength training symposium.
Dr. Schmidtbleicher is a world-renowned German researcher who has published a
huge body of work in the area of training and adaptation in strength and power
sports, periodization, the stretch shortening cycle, vibration training and
plyometrics. Here he presented some data from a recent research project he has
conducted and also discussed training for power in the context of this current
research and his entire body of research.
The data he
presented was from a study which examined the effects of strength training and
jump training on jumping performance. The vertical jump is often used a measure
of an individual’s power production capabilities (Carlock, 2004). In
Schmidtbleicher’s study there were three experimental groups and one inactive
control group. Group 1 trained exclusively with jump training, practicing
vertical countermovement jumps a number of times per week. Group 2 strength
trained. They performed heavy squats a number of times per week. Group 3 did a
combined training program which involved both heavy squatting and
countermovement jump training. There was strong control between groups for
training frequency and training volume. Subjects were tested before and after
their training intervention in the squat jump (a purely concentric jumping
action – it utilizes no stretch shortening cycle) and a countermovement jump.
All three
groups significantly increased jumping performance (in both squat and
countermovement jumps) in comparison to the control group. Interestingly, the
strength training group increased jumping performance more than the jump
training group by ~3-4% (although not significantly so). Importantly, the
combined training program increased jumping performance to a significantly
greater extent than the isolated jump training. Schmidtbleicher suggests this
data is strong evidence which demonstrates the key role maximal strength plays
in dynamic power production. This role is graphically represented in figure 1.
Schmidtbleicher suggests that an increase in maximal strength will result in an
increase to power and athletes’ rates of force development.
Figure 1:
Schematic representation of the relationship between strength, power and rate of
force development. (Schmidtbleicher, 2006; ISBS Symposium)
Drawing on
some of his previous research Schmidtbleicher also discussed possible methods of
periodization for athletes involved in training for power sports. He suggested
an undulating method of periodization is most effective. His past research has
suggested that this approach is more effective than traditional training blocks
or “macro-cycles”. More information regarding undulating periodization can be
found
here.
One example of such a training cycle would be to train for maximal strength on a
Monday, to train fast stretch shortening cycle (SSC) activities on a Wednesday
and to train slow SSC activities on a Friday. Training for hypertrophy could
also be included into such a weekly training plan depending on the athlete’s
specific needs. Examples of a slow SSC activity would be countermovement jumps.
Fast SSC activities have much faster transition times between the eccentric and
concentric components. A plyometric drop jump is an example of a fast SSC
action. Schmidtbleicher emphasized that slow and fast SSC activities are very
different movements and involve very different neural activation patterns. From
a standpoint of specificity he even went as far to say that training in slow SSC
activities will not significantly accrue benefit in fast SSC ability, and vice
versa.
Schmidtbleicher regards drop jumps and other fast stretch shortening cycle
activities as essential to the training preparation of the speed/power athlete.
He stressed however that drop jumping activities must be optimized to ensure
their effectiveness. This is done primarily by optimizing the drop height. Too
great a dropping height can increase the eccentric loading beyond the reactive
strength capabilities of the athlete, while too small a drop height may not
encourage a prestretch sufficient enough to maximally augment the concentric
portion of the jumping action. The appropriate drop height to perform drop jumps
from can be optimized through analyzing the height to which athletes jump to and
their ground contact times during drop jumps from varying heights.
Also, to
increase the fast SSC capabilities of the athlete Schmidtbleicher highly
recommends performing these exercises in a completely non-fatigued condition.
For this reason, while strength and jump training can be incorporated into the
same training week, they should not be combined in the same training session. He
recommends that a drop jump training session could include approximately 3-5
sets of 8-12 drop jumps. To ensure fatigue does not develop and the quality of
exercise performance is high he recommends as much as 8 seconds recovery between
jumps and 10 minutes recovery between sets.
Another
interesting presentation during the strength training symposium was that by
Carson Patterson from the University of Innsbruck. He investigated the
possibility of utilizing weighted vertical countermovement and squat jumps as a
replacement exercise for cleans in power athletes. The clean offers a very
effective non-specific method to assist athletes in developing power output
capabilities (Hydock, 2001; Hori, 2005). When performed correctly there is
strong kinematic
similarities in hip and knee extension observed during the clean (or power
cleans) and vertical jumping (Hori, 2005).
Research has shown that performance in the vertical jump is strongly correlated
to performance in power dependent sports (Sawyer 2002). However the
effectiveness of the clean in a power training program can be limited by the
technical proficiency of the lifter (Hydock, 2001; Hori, 2005). Poor technical
efficiency can limit the transfer of power production in the clean to specific
sports events. Examples of poor technical proficiency which would limit
transfer to sports would be poor positioning through the second pull, a lack of
utilization of the “double knee bend” (Hydock, 2001) or a failure to reach full
extension at the knees and hips. Therefore, it is questionable as to whether the
clean should be used in the training programs of athletes who struggle to learn
the appropriate technique.
The research
presented by Patterson demonstrated that the power produced in weighted vertical
jumps can be comparable or even greater than that produced by technically
proficient lifters in the clean. This suggests that the weighted jumps might be
a suitable, technically simpler exercise to replace the clean for those athletes
who have problems learning the clean successfully.
In this
research study the experimenters utilized a rigged safety apparatus which
winched the weighted barbell up off the athletes’ shoulders after the peak of
the vertical jump. This way the athletes did not land with the weight on their
back which eliminated any dangerous impact loadings on the lumbar region or on
the knee joints upon landing. Future research needs to examine the amount of
weight that can be safely utilized in this exercise for athletes who do not have
availability to such an apparatus.
Figure 2:
Shane Hamman
The ISBS’ 24th
annual International Symposium on Biomechanics in Sports was very well organized
and a fantastic success. The conference closed with the announcement that Seoul,
Korea would be the hosts of the 2008 Symposium. It had previously been decided
that the 2007 event would be hosted in Ouro Preto, Brazil. This will be the
first time that the conference will be hosted in Latin America, further
enhancing the internationalization of the society and the symposium.
References:
The
proceedings of the XXIV International Symposium on Biomechanics in Sports.
(2006) Vol. 1 & 2; July 14 – 18, Salzburg, Austria.
Carlock, M.,
Smith, S.L., Hartman, M.J., Morris, R.T., Ciroslan, D.A., Pierce, K.C., Newton,
R.U., Harman, E.A., Sands, W.A. and Stone, M.H. (2004) The relationship between
vertical jump power estimates and weightlifting ability: A field-test approach.
Journal of Strength and Conditioning Research, 18, 534–539.
Hori, N.,
Stone, M.H. (2005) Weightlifting exercises enhance athletic performance that
requires high-load speed strength. Strength and Conditioning Journal. 27: 50-55.
Hydock, D.
(2001) The weightlifting pull in power development. Strength and Conditioning
Journal. 23: 32-37
Sawyer D.T.,
Ostarello J.Z., Suess E.A. and Dempsey, M. (2002) Relationship between football
playing ability and selected performance measures. Journal of Strength and
Conditioning Research, 16, 611-616.
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