Identification of feigned ankle plantar and dorsiflexors weakness in normal subjects

The eccentric, concentric strength relationship of the hamstring muscles in chronic low back pain

“…The DEC is based on the rationale that a subject feigning effort will exhibit torque reduction not only concentrically, but also in the low velocity eccentric action. While valid for some joints (Dvir, 1997;Dvir and David, 1996;Dvir and Keating, 2001;Dvir et al, 2002), this does not seem to be the case for muscles about the ankle (Olmo et al, 2008) or, as found in the current study, the hamstrings. There is only one study we know of that used the DEC in a clinical LBP population (Dvir and Keating, 2003).…”

“…The DEC is obtained by subtracting the eccentric/ concentric strength ratio at the lower velocity from the ratio calculated at the higher velocity. The DEC has been shown to be 2-10 times greater in sub-maximal compared to maximal efforts (Dvir and Keating, 2001;Olmo et al, 2008). More recent work in the muscles of the ankle joint suggested that the sum eccentric-concentric (SEC), is a more appropriate measure for discriminating feigned performance than the DEC (Olmo et al, 2008).…”

“…The DEC has been shown to be 2-10 times greater in sub-maximal compared to maximal efforts (Dvir and Keating, 2001;Olmo et al, 2008). More recent work in the muscles of the ankle joint suggested that the sum eccentric-concentric (SEC), is a more appropriate measure for discriminating feigned performance than the DEC (Olmo et al, 2008). The SEC is quantified by adding the ratio of peak eccentric torque at high velocity to concentric torque at low velocity, to the eccentric to concentric ratio at high velocity (Olmo et al, 2008).…”

“…More recent work in the muscles of the ankle joint suggested that the sum eccentric-concentric (SEC), is a more appropriate measure for discriminating feigned performance than the DEC (Olmo et al, 2008). The SEC is quantified by adding the ratio of peak eccentric torque at high velocity to concentric torque at low velocity, to the eccentric to concentric ratio at high velocity (Olmo et al, 2008). This measure was designed to emphasize the contrast between any voluntarily reduced torques in the concentric action at both movement velocities with the less controllable high velocity eccentric action.…”

Association of Jumping Mechanography-Derived Indices of Muscle Function with Tibial Cortical Bone Geometry

“…First, muscle CSA and quadriceps torque are poor surrogate markers of muscle force as they correlate only moderately to peak jump force and power. On the one hand, although isokinetic dynamometry theoretically represents a good method for the evaluation of leg muscle function, as maximum muscle forces are generated during eccentric contractions [8,17], it is a rather impractical technique yielding a large variability in peak torque output due to methodological difficulties [8,35]. On the other hand, the use of muscle size measurements such as muscle CSA as a surrogate of maximum intrinsic muscle force is limited, because the mechanical potential of a muscle depends not only on morphology but also on muscle fibre type and muscle composition [36].…”