Exploring Passive Exoskeleton-Induced Changes in Lumbar Muscle Activity

Purpose: The purpose of this study was to evaluate the effect of using a passive exoskeleton on lumbar muscle activity during lifting movements, and to determine whether muscle activity remains altered after exoskeleton removal. This study sought to identify the potential risks and benefits associated with the use of passive exoskeletons for the prevention and treatment of low back pain. Methods: Eighteen healthy adult participants lifted a 10 kg suitcase while wearing a passive exoskeleton. Muscle activity and postures were measured during lifting and before, during, and after exoskeleton use. This study examined whether the reduced muscle activity observed during exoskeleton use persisted after exoskeleton removal. Muscle activity was assessed using electromyography and postures were recorded using reflective markers and a camera. Results: The study found that Lumbar muscle activity decreased significantly (approximately 40%) during exoskeleton use compared to that without exoskeleton use. Importantly, lumbar muscle activity remained low after exoskeleton removal, at levels similar to those observed during exoskeleton use. This suggests that individuals adapted to the exoskeleton support and maintained altered muscle control, even without the exoskeleton. Conclusion: This study demonstrates that passive exoskeletons significantly reduce lumbar muscle activity during lifting tasks, and that this altered muscle control persists after exoskeleton removal. These findings contribute to the understanding of the risks and benefits of passive exoskeletons, potentially aiding their development and informing their use in the prevention and treatment of low back pain.

Possibility of a Novel Warm-Up Strategy Using Capacitive and Resistive Electric Transfer: A Pilot Study

[Purpose] Capacitive and resistive electric transfer (CRET) is becoming prevalent in sports settings. CRET is effective for improving pain and healing injured tissue;however, its influence on muscle function and morphology is still unclear. This study confirmed the immediate effects of CRET on the duration of muscular stiffness and range of motion (ROM). [Method] This study describes the protocol for a single-arm trial with the non-blinding of participants and researchers. Twenty-four healthy men participated in the study. They received CRET therapy for their low back areas. The muscular stiffness of the multifidus muscle (superficial and deep) and the ROM using the active straight leg raise (ASLR) test were measured pre-intervention, post-intervention (immediately), and 15 and 30 min post-intervention. We compared these parameters using a one-way analysis of variance and Dunnett’s test (multiple comparison tests for subtests). [Results] The muscular stiffness of the superficial and deep multifidus muscles was significantly decreased, and the ASLR test showed a significant increase compared with the test performed pre-intervention. In addition, these effects persisted for 30 min. [Conclusion] Warm-up is vital for improving muscular stiffness and increasing the ROM. CRET is a useful device for achieving these aims, particularly as a passive warm-up method in sports settings.

Effect of Verbal Instructions in Pain Assessment during a Passive Straight Leg Raise Test in People with Chronic Low Back Pain

The most prevalent issue in physical therapy is pain. Due to the subjective nature of pain, assessment tools are essential in understanding it as objective data. However, assessment of pain may result in distress for the patient. A physical therapist (PT) should conduct these tests as quickly and accurately as possible. Straightforward instructions are vital in such cases. This study aimed to clarify the effect of verbal instructions for pain assessment during a passive straight leg raise (PSLR) test for participants with chronic low back pain (CLBP). This study included 22 participants who provided informed consent and received three consecutive PSLR tests with measurement of the hip flexion range of motion (HFROM) and were instructed to cease the test at submaximal pain before the first test. Following the second and third tests, participants were given specific verbal instructions to remember pain intensity, quality, and location. After each test, participants were to circle the pain location on the body chart and rate their pain intensity on a numeric rating scale (NRS) and pain quality. All participants were then interviewed about the differences between having and not having specific verbal instructions. The results of HFROM, NRS, and pain extent were not significantly different between the first and second tests or between the second and third tests using a paired t-test. Eleven changes in pain location were found in the second test compared to those in the first test. In the third test, only three participants circled a different area than in the second test. Ten participants showed similar changes with pain location in pain quality in the three PSLR tests. This study revealed the effect of specific verbal instructions prior to PSLR tests. Particularly, participants could notice exact pain location. Our findings may help PT to understand pain cause and reduce patients’ stress during pain assessment in clinical settings.