Elbow kinematics during sit-to-stand and stand-to-sit movements

Review of arm motion analyses

Interest in arm movements has increased tremendously in recent years. This interest has been motivated by different goals: the desire for a more scientific approach to replacement or support of the joints of the upper limb, the need for input to biomechanical computer models, and the clinical interest in comparing normal movements with pathological movements. The availability of commercial marker-tracking systems has facilitated achieving these goals. However, the complex nature of arm movements and the lack of standardized movements raises many challenges. In comparison with gait analysis, few arm motion analyses have been conducted. The purpose of this review is to aid researchers and clinicians interested in conducting an arm motion study in choosing the appropriate methodology. This is accomplished both by describing the methods used in past investigations and by highlighting important findings. Due to the variety of research goals, there is sometimes more than one appropriate method and the choice is left to the reader. Nevertheless, since it is extremely desirable to record and express the data in a standardized way, standardization proposals are described. This review, which focuses on methodology rather than results, addresses the following topics: motivations and tasks studied, tracking methods, the shoulder complex, joint centres and rotation axes, marker positions, coordinate system definitions, terminology and rotations, accuracy, and presentation methods.

Arm motion and load analysis of sit-to-stand, stand-to-sit, cane walking and lifting

OBJECTIVE

To conduct a pilot study to characterize the hand loads, arm joint angles and external moments corresponding to five activities of daily living demanding of the shoulder, for healthy subjects over 50 years of age.

DESIGN

The tasks were sit-to-stand, stand-to-sit, cane walking, lifting a 5 kg box with both hands, and lifting a 10 kg suitcase.

BACKGROUND

Arm motion and loading have not been previously studied for functional daily-living tasks involving substantial external loads.Methods. Motion was tracked using an optoelectronic system. Loads were measured using an instrumented chair arm, a force plate, and gravitational and acceleration loads. Six healthy volunteers (3 male, 3 female), mean age 55, with no history of shoulder problems participated in the study.

RESULTS

Average peak external moments ranged from 12.3 N m for sitting down into a chair to 27.9 N m for lifting a suitcase. Except for lifting the box, which had much lower loads, average peak hand loads varied from 16% to 19% of body weight (114-134 N). The arcs of motion were larger than for seated activities of daily-living studied previously.

CONCLUSIONS

The five tasks studied are commonly performed, yet involve large external moments. Lifting represents the greatest potential loading at the shoulder as it resulted in the highest external moments; furthermore, loads larger than those used in this study might be commonly lifted.

RELEVANCE

External moments at the shoulder should not be underestimated, even for activities of daily living.

Dynamics of the upper limb during performance of the tasks of everyday living--a review of the current knowledge base

This paper provides a brief review of the published literature on the subject of kinematics and kinetics of the human arm and shoulder mechanism, specifically when performing the tasks of everyday living. Surprisingly, only a small number of papers covering functional analysis of the arm were found, and the majority of these were concerned only with the kinematics of the elbow and lower arm. Differences in experimental method and a lack of consensus as to how to model the joint axes of the human arm make the results difficult to compare. Results are normally only presented in the form of angular excursion of the arm segments, with only one paper providing data on angular velocities and accelerations. The results of the different analyses suggest that the human arm is adaptive (due to its inherent mechanical redundancy), showing the ability to perform the same tasks using differing kinematic strategies. Therefore, the principal interest for the designer of upper limb orthoses should be the work-space defined by the start and end points of the hand, and the maintenance of the desired hand orientation when performing these tasks.

Elbow kinematics during sit-to-stand-to-sit of subjects with rheumatoid arthritis

Independence in mobility is dependent on the ability to rise from a chair. Elbow kinematics of subjects with rheumatoid arthritis were compared to those of subjects with no known elbow pathology. Through a case study approach, four subjects with varying elbow pathology and symptoms, were compared with a control group of 10 subjects on four kinematic variables. Results indicated that whereas the overall movement pattern was similar between the two groups, a trend toward increased deviation occurred with increased elbow involvement (as measured using the Morrey Elbow Evaluation). The total time taken to complete the task increased and the maximum velocity decreased as scores on the Morrey Evaluation decreased. When the minimum flexion angle (maximum extension) used during the activity was compared with the minimum flexion angle available, the angle used was consistently 15 degrees to 20 degrees less than that available. This possible need for a residual range raises questions about the generally accepted belief that activities require between 30 degrees to 130 degrees of flexion and 100 degrees of rotation.