Logo of nihpaAbout Author manuscriptsSubmit a manuscriptHHS Public Access; Author Manuscript; Accepted for publication in peer reviewed journal;
PMC full text:
J Electromyogr Kinesiol. Author manuscript; available in PMC 2013 Dec 1.
Published in final edited form as:
J Electromyogr Kinesiol. 2012 Dec; 22(6): 814–820.
Published online 2012 Jun 20. doi:  10.1016/j.jelekin.2012.04.006

Table 2

Estimated %MVC required to statically maintain the trunk at 20°, 40° and 60° forward flexion.

Flexion Angle (FA)
20°40°60°Source*

A. Trunk mass (including torso, head, neck, arms but not pelvis)
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Table 3.11 & Appendix B.1
B. Distance from pivot at L5- S1 intervertebral disc to center of trunk mass at T8–9 intervertebral disc
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Table 3.9 & Appendix B.2
C. Calculated moment arm from L5-S1 (B.*sin(FA))8.91cm16.75cm22.57cm
D. Calculated moment required to support 60kg male (A.*C.*9.8kg m/s2)18.34Nm34.47Nm46.82Nm
E. Maximal strength for torso extension for males288Nm232Nm171NmTable 4.5
F. Estimated %MVC required to support trunk mass (D./E.)*100%6.3%14.9%27.4%

bm, body mass; cm, centimeters, Nm, Newton-meters, MVC, maximal voluntary contraction.

*Data obtained from tables or narrative in Chaffin et al (1999) which also provides the original source.
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