An investigation of implicit bias about bending and lifting.

OBJECTIVES: Previous studies in a high-income country have demonstrated that people with and without low back pain (LBP) have an implicit bias that bending and lifting with a flexed lumbar spine is dangerous. These studies present two key limitations: use of a single group per study; people who recovered from back pain were not studied. Our aims were to evaluate: implicit biases between back posture and safety related to bending and lifting in people who are pain-free, have a history of LBP or have current LBP in a middle-income country, and to explore correlations between implicit and explicit measures within groups. METHODS: Exploratory cross-sectional study including 174 participants (63 pain-free, 57 with history of LBP and 54 with current LBP). Implicit biases between back posture and safety related to bending and lifting were assessed with the Implicit Association Test (IAT). Participants completed paper-based (Bending Safety Belief [BSB]) and online questionnaires (Tampa Scale of Kinesiophobia; Back Pain Attitudes Questionnaire). RESULTS: Participants displayed significant implicit bias between images of round-back bending and lifting and words representing "danger" (IATD-SCORE: Pain-free group: 0.56 (IQR=0.31-0.91; 95% CI [0.47, 0.68]); history of LBP group: 0.57 (IQR=0.34-0.84; 95% CI [0.47, 0.67]); current LBP group: 0.56 (IQR=0.24-0.80; 95% CI [0.39, 0.64])). Explicit measures revealed participants hold unhelpful beliefs about the back, perceiving round-back bending and lifting as dangerous (BSBthermometer: Pain-free group: 8 (IQR=7-10; 95% CI [7.5, 8.5]); history of LBP group: 8 (IQR=7-10; 95% CI [7.5, 9.0]); current LBP group: 8.5 (IQR=6.75-10; [7.5, 9.0])). There was no correlation between implicit and explicit measures within the groups. CONCLUSIONS: In a middle-income country, people with and without LBP, and those who recovered from LBP have an implicit bias that round-back bending and lifting is dangerous.

Back pain attitudes questionnaire: Cross-cultural adaptation to brazilian-portuguese and measurement properties.

BACKGROUND: The Back Pain Attitudes Questionnaire (Back-PAQ) was developed to evaluate attitudes and beliefs of the general public, people with back pain, and healthcare professionals about the spine. OBJECTIVES: To translate and cross-culturally adapt the Back-PAQ (34-item and 10-item versions) into Brazilian-Portuguese (Back-PAQ-Br) and test its measurement properties in a Brazilian sample. METHODS: The cross-cultural adaptation and testing of the measurement properties followed the recommendations of international guidelines. Members of the general public, people with back pain, and healthcare professionals, for a total of 139 individuals, took part in the assessment of internal consistency, construct validity, and ceiling and floor effects. The Hospital Anxiety and Depression Scale (HADS) and the Brazilian-Portuguese version of the Tampa Scale of Kinesiophobia (TSK) were used to evaluate construct validity. Test-retest reproducibility was determined on 77 participants. Retest was performed a minimum of 1 week and a maximum of 2 weeks from the original test. RESULTS: There was very high agreement between translators (88.2%). The Back-PAQ-Br showed excellent internal consistency (Cronbach's alpha 0.92) and excellent reproducibility (ICC 0.94; SEM 5.14 points on a 136 point scale), with a smallest detectable change (90% confidence level) of 11.93 points. There was strong correlation between Back-PAQ-Br and TSK (r = -0.72) and very weak correlation between Back-PAQ-Br and HADS (r = -0.23 for both depression and anxiety domains). No ceiling/floor effects were observed. CONCLUSION: The translation process and cross-cultural adaptation had very high agreement between translators. The Back-PAQ-Br has excellent measurement properties that are similar to the properties of the original version.

A comparison between two models of shoulder muscle force estimation.

Shoulder injuries are often related to rotator cuff muscles. Although there are various models for muscle force estimation, it is difficult to ensure that the results obtained with such models are reliable. The aim of the current study was to compare two models of muscle force estimation. Eight subjects, seven male and one female (mean age of 24 yr; mean height of 1.83 m), performed five isokinetic maximum concentric contractions of internal and external shoulder rotation. Two models with different algorithms were used. In both, the input data consisted of the measured internal rotation moment. Comparisons were made between the difference and the average results obtained with each model of muscle force estimation. There was reasonable agreement among the results for force between the two models for subscapularis, pectoralis major, and anterior deltoideus muscles results. Conversely, poor correlation was found for the latissimus dorsi, teres major, and middle deltoid. These results suggest that the algorithm structure might have a strong effect on muscle force estimation results.

Torque and force production during shoulder external rotation: differences between transverse and sagittal planes.

In joints with 3 degrees of freedom, such as the shoulder joint, the association of different movements results in changes in the behavior of the moment arm of the muscles. The capacity of torque production for the same movement can be changed when movements take place in a different plane. The objective of this study is to quantify differences between torque production and resultant force estimated during the shoulder external rotation in two movement planes: the transverse and sagittal planes (with 90 degrees of shoulder abduction). Eight individuals were evaluated using an isokinetic dynamometer and an eletrogoniometer for movements in the transverse plane and six individuals for movements in the sagittal plane. The results showed that the execution of the external rotation in the sagittal plane allowed greater torque magnitudes and resultant force compared with those in the transverse plane, probably owing to a prestretching of infraspinatus and teres minor.