Effects of body mechanics training on performance of repetitive lifting.

OBJECTIVE: To measure the efficacy of body mechanics instruction (BMI) in patients with low back pain. METHOD: The effect of BMI was measured in four participants with back injuries using a standardized lifting protocol. Static strength, weight lifted, number of lifts completed, and motion analysis data to describe the body mechanics were measured before and after work hardening to evaluate treatment effects. The participants' performances were compared with 52 controls from an earlier study. RESULTS: Starting postures, characterized by degrees of hip and knee flexion, varied by participant but favored a squat lift in three participants when compared with the controls. Dynamic motion synchrony of the hip and knee joints was similar to controls in three of the four participants. Posttest data revealed significant changes in static strength, dynamic endurance, and lifting speed. CONCLUSION: Intensive instruction in body mechanics provided during the work-hardening treatment produced major changes in lifting styles, in terms of both starting postures and dynamic aspects of repetitive lifting. The computerized measurement procedures used in this study permitted more careful and detailed analyses of body mechanics, particularly dynamic aspects, than is possible with observational methods. This study demonstrated some of the inherent intricacies in isodynamic lifting and suggests additional areas of performance that may be important to address in BMI.

Functional capacity assessment: Influence of behavioral and environmental factors.

The environment surrounding the functional capacity evaluation (FCA) is complex and determined by both external factors as well as those specific to the testing situation. In this paper we (1) briefly review existing models of pain, (2) highlight how current FCAs of pain patients adhere in general to behavioral conceptualizations of chronic pain, (3) review some inadequacies of current conceptualizations of FCA when it applies to chronic pain, (4) review the many internal and external environmental factors that can significantly influence FCAs, and (5) consider some psychosocial factors that play an important role in patients' performances. We conclude that not only should evaluators more carefully consider the central influences of psychosocial factors when interpreting the results of FCAs, but that an alternate conceptual model that emphasizes both environmental and psychological factors is also needed to more adequately describe the physical performances obtained during FCAs.

Body motion patterns during a novel repetitive wheel-rotation task. A comparative study of healthy subjects and patients with low back pain.

STUDY DESIGN: This study evaluated performance differences between patients with chronic low back pain and a control group during their performance of a novel functional capacity task. OBJECTIVE: To 1) evaluated strength and endurance differences between patients and control subjects, 2) test for movement pattern differences between these groups, and 3) evaluate how these patterns changed with repetitive performance of the wheel-turning task. SUMMARY OF BACKGROUND DATA: Despite increased emphasis on quantifying functional capacities, few well-controlled studies comparing the performances of patients with low back pain with those of control subjects have appeared in the literature, particularly for movement patterns. METHODS: Forty patients with low back pain and 40 control subjects performed a sustained isodynamic wheel turning task. This task was selected because it simultaneously combined several common pain-related movements. A set of kinematic measures to characterize the basic movement patterns during this task were developed. RESULTS: Control subjects produced significantly higher levels of static torque and completed significantly more wheel-turning repetitions. Patients with low back pain exhibited significantly less upper torso and pelvic motion, upper torso rotation, and lateral trunk flexion than those in the control group. CONCLUSION: The dissimilar movement strategies found between the patient and control groups suggests that factors beyond more global physical explanations (e.g., deconditioning) may be important in accounting for the large discrepancy between these groups regarding the amount of work performed. These findings, along with the basic kinematic patterns developed in this study, may have important implications for determining the efficacy of instruction in body mechanics and treatment outcome for patients with chronic low back pain.

Measuring treatment effects on repetitive lifting for patients with chronic low back pain: speed, style, and coordination.

The purpose of this study was to determine changes in the amount of work performed and lifting speed, style, and coordination during a repetitive dynamic-lifting task for patients with chronic low back pain (CLBP) after an intensive 3 1/2-week pain rehabilitation program. Subjects included 57 CLBP patients and an age- and gender-matched control group (n = 57). Patients' work indices increased by 71%, but remained significantly less than those observed for controls. Similarly, their lifting speed also increased significantly after treatment, but remained slower than the lifting speed of controls. Patients' posttreatment coordination indices, however, were not significantly different from those of controls. This finding suggests that treatment effectively normalized the dynamic lifting motion used by the patients. These findings, along with the basic kinematic patterns developed in this study, have important implications for determining improvements in functional capacity in the treatment of patients with CLBP.