A presentation on CJ cummings fro 2014 youth nationals

1. Anthropometrics and Bar Kinematics
of the Snatch Technique in an
Elite Youth Weightlifter:
C.J. Cummings
Bob LeFavi, PhD, CSCS, USAW
Armstrong State University (Savannah, GA)
Team Savannah

2. C.J. Cummings

3. Weightlifting Accomplishments
• At 11 years old, double bodyweight clean and jerk; first in history.
• In December 2012, C.J. was the youngest lifter ever to compete in (qualify for)
the American Open in Palm Springs, CA. He placed second as a 12 year-old!
• From 2013 to present, C.J. has been the #1 ranked 17 & under male lifter in U.S.
• In April 2013, as a 12 year-old, C.J. was the youngest competitor in history to
represent the U.S. at an international weightlifting championship.
• In 2013, C.J. lifted for Team USA at the International Weightlifting Federation’s
15 & Under Pan American Championships, where he won, was awarded the
best overall lifter, and set new Pan American records. This was the first time in
over a decade that a U.S. male has broken an International record.
• After the Pan Americans, USA Weightlifting designated C.J. the strongest 13 &
Under lifter in the Western Hemisphere. USAW later designated him as the
strongest 13 & Under lifter in the world!
• In 2014, at 13, C.J. won the 62 KG class at 17 & Under Pan American
Championships in May in Peru.

4. Purpose
• Identify anthropometric and performance
variables of this elite Youth weightlifter.
• Compare data against current
recommendations and thought.
• Initiate a database of anthropometric and
performance variables so that weightlifting
talent may be mot easily identified in the
future.

5. Literature on Athropometrics
• Anthropometrics
– Identified certain variables as advantageous to
weightlifting, yet scant amount of actual research
– National Coach Zygmunt Smalcerz (previously
identified talent in Poland) has published
anthropometric preferences.
– Studies on powerlifters show similarities (longer arms
than normal) and differences (shorter torso relative to
leg length in powerlifters; shorter leg length relative
to torso in weightlifters) in optimal anthropometrics.

6. Anthropometric Measurements
• Bodyweight and height
• Body Segments:
– Total arm length (acromion process to dactylion)
– Torso length (acromion process to greater trochanter)
– Femur length (greater trochanter to lateral femoral
condyle)
– Tibia length (lateral femoral condyle to lateral
malleolus)
– Forearm length (olecranon process to styloid process)
– Hand length (interstylon midpoint to dactylion)

7. Literature on Barbell Kinematics
• Barbell kinematics
– Early work done by Dr. John Garhammer and Dr.
Michael Stone. Identification of technique
variables in world-class weightlifters. Looked at:
• Optimal bar displacement (total distance bar travels).
• Vertical velocity pattern throughout lift (speed of bar
upward; max velocity reached towards end of 2nd pull).
• Barbell trajectory patterns (path of bar relative to
vertical reference line, focused on minimizing distance
away from that line)

8. Does Optimal Technique Exist?
• Or if the question is, “What is optimal for a certain
individual?”, then what data do we have to assist coaches in
identifying a lifter’s optimal technique?

9. Barbell Kinematics
• 3D motion analysis
• 10 cameras
• Two marker sets of three reflective markers
• Trials of single repetitions were completed at
40 kg, 50 kg, 60 kg, 70 kg, 80 kg, and 90 kg
• The trials ranged from 35% - 80% of the
subjects one repetition maximum

10. RESULTS: Anthropometrics
Height – 160 cm Weight – 64 kg
Absolute Variables (cm)
Left Right
Total Arm 54 53.5
Forearm 27 27
Hand 18.5 18.5
Torso 47.5 48
Femur 34.5 35
Tibia 45 44.5
• Smalcerz’s Suggestions:
– Long arms compared to torso
• Easy to lift bar off platform
• Harder to raise bar higher in
jerk
– Shorter femur length
compared to tibia
– Legs should not be more than
50 percent of total height
– Hand length should be at
least 16-16.5 cm

11. RESULTS: Barbell
Displacement
• As the weight increases,
the lifter is not able to
pull the bar as high
• Peak displacement in
successful lifts has been
shown to be lifted up to
70 percent of the lifters
height
• The bar was lifted as
low as 59 percent of the
lifters height for the
heaviest lift
(m) 40 kg 50 kg 60 kg 70 kg 80 kg 90 kg
2nd pull 1.15 1.15 1.09 1.06 1.05 0.95
Recovery 1.55 1.49 1.40 1.37 1.53 1.38

12. RESULTS:
Barbell Velocity
• Velocity should be
continuous throughout
the lift, although a dip in
velocity between the 1st
pull and 2nd pull is
common.
• Maximum velocity
expected to be seen
during the 2nd pull phase.
• Most research done on
heavy, competitive lifts
which reach a range of
1.68 to 1.98 m/s
3
2
1
0
-1
40 kg
1.7 1.9 2.1 2.3 2.5 2.7 2.9
Vertical Velocity (m/s)
Time (s)
3
2
1
0
-1
50 kg
1.7 1.9 2.1 2.3 2.5 2.7 2.9
Vertical Velocity (m/s)
Time (s)
3
2
1
0
-1
60 kg
1.7 1.9 2.1 2.3 2.5 2.7 2.9
Vertical Velocity (m/s)
Time (s)
3
2
1
0
-1
70 kg
1.7 1.9 2.1 2.3 2.5 2.7 2.9
Vertical Velocity (m/s)
Time (s)
3
2
1
0
-1
80 kg
1.7 1.9 2.1 2.3 2.5 2.7 2.9
Vertical Velocity (m/s)
Time (s)
3.0
2.0
1.0
0.0
-1.0
90 kg
1.6 1.8 2 2.2 2.4 2.6 2.8 3
Vertical Velocity (m/s)
Time (s)
Vmax
(m/s)
40 kg 50 kg 60 kg 70 kg 80 kg 90 kg
2nd pull 2.71 2.76 2.68 2.31 2.20 2.19

13. RESULTS:
Barbell Trajectory
• Lighter lifts, bar
extends further away
from body than usual
• Heavier lifts keep close
to vertical reference
line
• Second pull has unique
hitch
• Backward jump creates
increase in backward
horizontal
displacement

14. 90 KG snatch

15. Bar Trajectory Classifications
More type B? More type C? Three basic types of bar trajectories
that are widely used in research
Figure from Vorobyev, A.N. A Textbook
on Weightlifting, 1978
Similar to 70 kg lift Similar to 60 kg lift

16. Conclusion
• The results from this study are specific to this one
individual, and other lifters should not necessarily
adopt these patterns.
• C.J. Cummings has anthropometric and technique
characteristics that are somewhat unique.
• This data can be used to continue a database of
variables on characteristics of elite lifters in the
hope that such findings can assist coaches in the
identification of weightlifting talent or to
optimize a lifter’s potential.