Measurement of resistance exercise force expression
Issue Date
2004Author
Chiu, Loren Z. F.
Schilling, Brian K.
Fry, Andrew C.
Weiss, Lawrence W.
Publisher
Human Kinetics
Type
Article
Article Version
Scholarly/refereed, publisher version
Published Version
http://ehis.ebscohost.com/ehost/detail?sid=afef5b5e-42ad-4a92-896e-f02e050a2011%40sessionmgr10&vid=1&hid=17&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=s3h&AN=13021242Metadata
Show full item recordAbstract
Displacement-based measurement systems are becoming increasingly popular
for assessment of force expression variables during resistance exercise.
Typically a linear position transducer (LPT) is attached to the barbell to measure
displacement and a double differentiation technique is used to determine
acceleration. Force is calculated as the product of mass and acceleration. Despite
the apparent utility of these devices, validity data are scarce. To determine
whether LPT can accurately estimate vertical ground reaction forces,
two men and four women with moderate to extensive resistance training experience
performed concentric-only (CJS) and rebound (RJS) jump squats, two
sessions of each type in random order. CJS or RJS were performed with 30%,
50%, and 70% one-repetition maximum parallel back squat 5 minutes following
a warm-up and again after a 10-min rest. Displacement was measured via
LPT and acceleration was calculated using the finite-difference technique. Force
was estimated from the weight of the lifter-barbell system and propulsion force
from the lifter-barbell system. Vertical ground reaction force was directly
measured with a single-component force platform. Two-way random average-
measure intraclass correlations (ICC) were used to assess the reliability
of obtained measures and compare the measurements obtained via each method.
High reliability (ICC > 0.70) was found for all CJS variables across the loadspectrum.
RJS variables also had high ICC except for time parameters for
early force production. All variables were significantly (p < 0.01) related between
LPT and force platform methods with no indication of systematic bias.
The LPT appears to be a valid method of assessing force under these experimental
conditions.
Description
This is the publisher's version, also found at http://ehis.ebscohost.com/ehost/detail?sid=afef5b5e-42ad-4a92-896e-f02e050a2011%40sessionmgr10&vid=1&hid=17&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=s3h&AN=13021242
Collections
Citation
Chiu, Loren Z.F.; Schilling, Brian K.; Fry, Andrew C.; and Weiss, Lawrence W. (2004) Measurement of resistance exercise force expression. Journal of Applied Biomechanics, 20. 204-212.
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