Lumbopelvic Kinematics and Trunk Muscle Activity During Sitting on Stable and Unstable Surfaces

Abstract

Study Design: A single-group comparative study. Objectives: To compare lumbopelvic kinematics and muscle activation patterns while sitting on stable and unstable surfaces. Background: Unstable surfaces are commonly used during the rehabilitation of certain low back pain disorders. The benefits postulated are increased muscle activity and facilitation of sustainable midrange positions via neuromuscular control. The use of unstable sitting devices in the workplace is controversial, as the postulated increase in muscle activity is thought to lead to a muscle fatigue/pain response. However, little evidence exists for or against the ability of these devices to alleviate or prevent spinal pain. Methods and Measures:This study included 26 healthy adults (14 male, 12 female). Fastrak 3-dimensional motion analysis detected lumbar curvature, pelvic tilt, and postural sway during sitting on a stable and unstable surface over 5-minute periods. Surface electromyography was used to measure activity in the superficial lumbar multifidus, transverse fibers of internal oblique, and iliocostalis lumborum pars thoracis. Results: Spinal postures were similar for sitting on a stable and unstable surface. Significant increases in postural sway were detected (P = .013) in 3 dimensions of movement during sitting on an unstable surface. Gender differences were noted. No EMG amplitude or variance differences were detected between seating conditions. Conclusions: Preliminary data show that sitting on unstable surfaces induces greater spinal motion, but does not significantly alter the lumbosacral posture nor the amount of activity in the superficial trunk muscles under investigation.

The Short Term Musculoskeletal and Cognitive Effects of Prolonged Sitting During Office Computer Work

“…Skin preparation was undertaken (area shaved, cleaned with ethyl alcohol and lightly abraded with fine sand paper) before self-adhesive disposable Ag/AgCl (6 mm gel diameter) electrodes (Neuroplus, Vermed, New York, NY, USA) were secured with tape over the following muscles: right side upper trapezius (with 20 mm centre to centre distance 20 mm lateral to the midpoint between the acromion process and C7 spinous process [39]), external oblique (just below the rib cage and along a line connecting the most inferior point of the costal margin and the contralateral pubic tubercle [40]), lumbar erector spinae (iliocostalis lumborum pars thoracis at L1 spinous process level midway between the midline and the lateral aspect [41]), rectus femoris (midway along a line between the anterior superior iliac spine and superior border of the patella [42]) and biceps femoris (midway laterally on the posterior part of the thigh [42]). The common earth electrode was placed on the acromium.…”

“…Sensors at T12, L1 and S2 (based on the protocol by Levine and Whittle [48]) were secured over spinous processes. The earlier mentioned Labview program calculated a total low back angle (as the angle between T12 and S2 in the sagittal plane) and pelvis movement (as the distance, in centimetres, of transverse plane displacement of the S2 sensor [41]) for analysis.…”

The Effect of Trunk Stabilization Exercise Using an Unstable Surface on the Abdominal Muscle Structure and Balance of Stroke Patients

“…Trunk stabilization exercises strengthen the muscles associated with maintaining the posture of the limbs and give increased stability4 ) . Previous studies have reported the positive effects of trunk stabilization exercises on unstable surfaces possibly due to stimulation of the proprioceptors of the joint and muscle5, 6 ) . Also, trunk stabilization training on an unstable surfaces activates the postural muscles around the abdomen and pelvis, more than that on a stable surface.…”

Spine kinematics and trunk muscle activity during bipedal standing using unstable footwear

“…Genetic inheritance, psychosocial factors, but most likely deficits within the motor control system that lead to abnormal loads, may cause injuries at the vertebral column – particularly at the lower levels (McGill, ; Reeves et al., ). However, inherently static activities can be classified as provocative factors as well, since the corresponding lack of spinal motion may attenuate disc nutrition (van Deursen et al., ; O'Sullivan et al., ). Subsequently, intervention programs incorporating concepts of functional instability are frequently expected to maintain or regain back health by encouraging both somatosensory feedback mechanisms and active tissue stimuli (Collins et al., ; O'Sullivan et al., ; Behm et al., ).…”