The influence of rice plow handle design and whole-body posture on grip force and upper-extremity muscle activation

A previous job screening study revealed ergonomics risk factors in rice field plowing. This work motivated the present experimental investigation of the influence of plow handle design and farmer whole-body posture on grip force and arm muscle activity. A total of 24 experienced farmers performed a simulated plowing task, including walking on even and uneven ground while rolling a tiller equipped with conventional horizontal and proposed vertical handles. Results revealed the proposed handles, designed to promote neutral wrist posture, to increase upper-arm muscle use between 47% and 70% across ground types, as compared with conventional handles. The ratio of grip force to forearm muscle activity (or efficiency in muscle use) increased from 1.85 when using conventional handles on uneven ground to 2.16 when using the proposed handles with symmetrical body posture on even ground. However, participants perceived higher discomfort when using the proposed handles, as they were accustomed to the conventional design.     

Service robot feature design effects on user perceptions and emotional responses

Service robots have been developed to assist nurses in routine patient services. Prior research has recognized that patient emotional experiences with robots may be as important as robot task performance in terms of user acceptance and assessments of effectiveness. The objective of this study was to understand the effect of different service robot interface features on elderly perceptions and emotional responses in a simulated medicine delivery task. Twenty-four participants sat in a simulated patient room and a service robot delivered a bag of “medicine” to them. Repeated trials were used to present variations on three robot features, including facial configuration, voice messaging and interactivity. Participant heart rate (HR) and galvanic skin response (GSR) were collected. Participant ratings of robot humanness [perceived anthropomorphism (PA)] were collected post-trial along with subjective ratings of arousal (bored–excited) and valence (unhappy–happy) using the self-assessment manikin (SAM) questionnaire. Results indicated the presence of all three types of robot features promoted higher PA, arousal and valence, compared to a control condition (a robot without any of the features). Participant physiological responses varied with events in their interaction with the robot. The three types of features also had different utility for stimulating participant arousal and valence, as well as physiological responses. In general, results indicated that adding anthropomorphic and interactive features to service robots promoted positive emotional responses [increased excitement (GSR) and happiness (HR)] in elderly users. It is expected that results from this study could be used as a basis for developing affective robot interface design guidelines to promote user emotional experiences.     

Effects of seated lumbar extension postures on spinal height and lumbar range of motion during prolonged sitting

Prolonged sitting during sedentary work has been reported as a potential risk factor for low back pain. Furthermore, prolonged sitting can result in both reduced spinal height (SH) and lumbar range of motion (LROM). This study compared the effects of no intervention (control) with two recovery postures on SH and LROM (flexion and extension) during prolonged sitting. Twenty-four participants were randomly assigned to three interventions for three consecutive days. The interventions comprised two seated lumbar extension recovery postures (unsupported sustained and supported dynamic lumbar extension postures) and a control. Both interventions facilitated a relatively short recovery period for both SH and LROM. Supported dynamic lumbar extension conditions significantly helped SH recovery, as compared with control condition, after the first recovery posture intervention, and both postures have potential to maintain LROM. However, both postures failed to induce SH recovery over an extended time.     

The immediate effect of the abdominal drawing-in maneuver technique on stature change in seated sedentary workers with chronic low back pain

Abstract

Many studies have measured stature change arising from loads imposed on the spine during sitting. To improve stature recovery, it is important to stabilise the lumbar spine and compensate forces from the upper body. The abdominal drawing-in maneuver (ADIM) technique has been found to mainly activate deep trunk muscles. The purpose of this study was to determine whether activation of deep trunk muscles by the ADIM technique could immediately improve stature recovery during prolonged sitting. Twenty-four patients with chronic low back pain (CLBP) were randomly allocated into different orders of experimental conditions: control (sitting without ADIM technique) and intervention conditions (sitting with ADIM technique). The latter condition required participants to complete ADIM technique for 1?min and repeat it three times throughout 41?min prolonged sitting time. Stature recovery was improved by 3.292?mm in the intervention condition compared with control condition (p-value = 0.001). Our finding demonstrated that ADIM technique improved stature recovery.

Practitioner Summary: Prolonged sitting seemingly harms sedentary workers’ health, particularly affecting the lower back. Activation of deep trunk muscles using abdominal drawing-in maneuver technique can promote spinal recovery. Clinicians can teach abdominal drawing-in maneuver technique to activate deep trunk muscles in chronic low back pain, thereby promoting self-management of seated stature recovery.

Abbrevations: ADIM: abdominal drawing-in maneuver; RA: rectus abdominis; ICLT: iliocostalis lumborum pars thoracis; LM: lumbar multifidus; TrA: transversus abdominis; IO: internal oblique; CLBP: chronic low back pain; LBP: low back pain; RMDQ: Roland Morris disability questionnaire; NRS: numerical rating scale.     

Effects of restrictive clothing on lumbar range of motion and trunk muscle activity in young adult worker manual material handling

The objective of this study was to examine the effect of wearing restrictive trousers on lumbar spine movement, trunk muscle activity and low back discomfort (LBD) in simulations of manual material handling (MMH) tasks. Twenty-eight young adults participated in the study performing box lifting, liquid container handling while squatting, and forward reaching while sitting on a task chair when wearing tight pants (sizes too small for the wearer) vs. fit pants (correct size according to anthropometry). Each task was repeated three times and video recordings were used as a basis for measuring lumbar range of motion (LRoM). The response was normalized in terms on baseline hip mobility. Trunk muscle activity of rectus abdominis (RA) and erector spinae (ES) muscles were also measured in each trial and normalized. At the close of each trial, participants rated LBD using a visual analog scale. Results revealed significant effects of both pants and task types on the normalized LRoM, trunk muscle activity and subjective ratings of LBD. The LRoM was higher and trunk muscle (ES) activity was lower for participants when wearing tight pants, as compared to fit pants. Discomfort ratings were significantly higher for tight pants than fit. These results provide guidance for recommendations on work clothing fit in specific types of MMH activities in order to reduce the potential of low-back pain among younger workers in industrial companies.