Comparison between two dynamic methods to estimate triaxial net reaction moments at the L5/S1 joint during lifting.

OBJECTIVE: The purpose of the study was to evaluate the validity of two biomechanical dynamic tridimensional (3D) multisegment models. DESIGN: An experimental study was conducted for this purpose. BACKGROUND: The models that were compared are commonly used to analyse lifting tasks. The upward model used the measured external forces at the feet, whereas the downward model used an estimation of the forces at the hands. The downward model approach is more practical to study manual materials handling (MMH) tasks but needs improvement to produce valid estimates. METHODS: One male subject participated in the study. Four cameras and two force platforms were used to get the data from 66 static and 108 dynamic trials. The triaxial net moments at L5/S1 of both models were compared. RESULTS: Good agreement was observed between the two models for the moments of the static tasks but great disparity was observed for the moments of the dynamic tasks (up to 78 Nm in extension). Both models were sensitive to different task parameters (movement or load asymmetry, movement rate, load magnitude). CONCLUSIONS: The direct measurement of the external forces at each hand is recommended. The validation should be performed with more subjects for generalization.

[1]  W S Marras,et al.  Trunk Strength during Asymmetric Trunk Motion , 1989, Human factors.

[2]  M Gagnon,et al.  The influence of dynamic factors on triaxial net muscular moments at the L5/S1 joint during asymmetrical lifting and lowering. , 1992, Journal of biomechanics.

[3]  D B Chaffin,et al.  A dynamic biomechanical evaluation of lifting maximum acceptable loads. , 1984, Journal of biomechanics.

[4]  A Plamondon,et al.  Pivoting with the load. An alternative for protecting the back in asymmetrical lifting. , 1993, Spine.

[5]  M. de Looze,et al.  Validation of a dynamic linked segment model to calculate joint moments in lifting. , 1992, Clinical biomechanics.

[6]  G. Street.  Biomechanics IX-B , 1985 .

[7]  A Leardini,et al.  Position and orientation in space of bones during movement: anatomical frame definition and determination. , 1995, Clinical biomechanics.

[8]  D. Warwick,et al.  Trunk Strengths in Attempted Flexion, Extension, and Lateral Bending in Healthy Subjects and Patients with Low‐Back Disorders , 1980, Spine.

[9]  Mary Elizabeth Danz.  Measured and modeled hand forces and resulting forces at the low back during the pull phase of a lifting task , 1991 .

[10]  W. T. Dempster,et al.  SPACE REQUIREMENTS OF THE SEATED OPERATOR, GEOMETRICAL, KINEMATIC, AND MECHANICAL ASPECTS OF THE BODY WITH SPECIAL REFERENCE TO THE LIMBS , 1955 .

[11]  H M Toussaint,et al.  The evaluation of a practical biomechanical model estimating lumbar moments in occupational activities. , 1994, Ergonomics.

[12]  A Plamondon,et al.  Moments at the L(5)/S(1) joint during asymmetrical lifting: effects of different load trajectories and initial load positions. , 1995, Clinical biomechanics.

[13]  A. Plamondon,et al.  Validation of two 3-D segment models to calculate the net reaction forces and moments at the L(5)/S(1) joint in lifting. , 1996, Clinical biomechanics.

[14]  H. Röhrle,et al.  Joint forces in the human pelvis-leg skeleton during walking. , 1984, Journal of biomechanics.

[15]  Vladimir M. Zatsiorsky,et al.  The Mass and Inertia Characteristics of the Main Segments of the Human Body , 1983 .

[16]  Gerald A. Smith,et al.  Padding point extrapolation techniques for the Butterworth digital filter. , 1989, Journal of biomechanics.

[17]  M E Danz,et al.  The effects of speed, frequency, and load on measured hand forces for a floor to knuckle lifting task. , 1992, Ergonomics.

[18]  A. C. Eycleshymer,et al.  A cross-section anatomy , 1970 .

[19]  David A. Winter,et al.  Biomechanics and Motor Control of Human Movement , 1990 .

[20]  P. Devita,et al.  Errors in alignment of center of pressure and foot coordinates affect predicted lower extremity torques. , 1995, Journal of biomechanics.

[21]  A Mital,et al.  Biomechanical analysis of manual lifting tasks. , 1987, Journal of biomechanical engineering.

[22]  S. Plagenhoef,et al.  Patterns of human motion;: A cinematographic analysis , 1971 .

[23]  G. Andersson.  Epidemiologic Aspects on Low-Back Pain in Industry , 1981, Spine.