The Effects of Lifting Posture on Trunk Muscle Activity

1992 ◽  
Vol 36 (10) ◽  
pp. 742-746
Author(s):  
Christopher A. Hamrick ◽  
Sean Gallagher

Trunk muscle activity of twelve healthy males with coal mining experience was examined while each subject lifted a box under various conditions. The independent variables were four levels of posture (kneeling, stooped under a 1.2 m roof, stooped under a 1.6 m roof, and standing), height to which the box was lifted (35 cm or 70 cm), and weight of the lifting box (15 kg, 20 kg, or 25 kg). The dependent variables were the peak EMG values recorded during a lift for each of eight trunk muscles (left and right erectores spinae, left and right latissimus dorsi, left and right external oblique, and left and right rectus abdominis). Posture and weight of lift significantly affected peak activity of the left and right erectores spinae, the left and right latissimus dorsi muscles, and the right external oblique muscle. The latissimus dorsi muscle activity was highest in the low stooping posture, and was lowest in the kneeling posture, while erectores spinae activity was highest in the kneeling posture and decreased as the trunk became more flexed. Thus, the muscle activity during lifting tasks is affected by restricting a worker's posture. Consequently, many lifting guidelines and recommendations currently in use may not be directly applicable to work being performed in restricted postures.

2018 ◽  
Vol 21 (01) ◽  
pp. 1850004
Author(s):  
Aaron M. Flanagan ◽  
Xue-Cheng Liu ◽  
Steve Cope

Purpose: To determine if there is a difference in trunk muscle activation in children with spastic diplegic cerebral palsy (CP) compared to typically developing (TD) children while being held in different positions on a hippotherapy simulator. Methods: Five children with spastic diplegic CP and five TD children of similar age were recruited through the Children’s Hospital of Wisconsin. The participants were held in static positions sitting on a hippotherapy simulator at 10[Formula: see text], 15[Formula: see text], and 20[Formula: see text] from the midline to front, back, and side positions. Surface electromyography (sEMG) data were collected from the left and right latissimus dorsi, hip adductor, middle trapezius, and rectus abdominis muscles. The pooled mean sEMG amplitude, at each position, served as the main outcome measurement. Results: The forward position at 20[Formula: see text] for the left and right lower rectus abdominis and right middle trapezius muscles had an effect size of [Formula: see text]. This was also evident in the right middle trapezius at 10[Formula: see text] in the forward and left tilted positions, and in the right latissimus dorsi at the 10[Formula: see text] left tilted position. Conclusion: Different sEMG in the abdominal, middle trapezius, and latissimus dorsi muscles in children with spastic diplegic CP suggests that utilizing a trunk position of different angles may improve the current therapeutic methods in the recruitment of trunk muscles.


Author(s):  
Yuki Kurokawa ◽  
Satoshi Kato ◽  
Satoru Demura ◽  
Kazuya Shinmura ◽  
Noriaki Yokogawa ◽  
...  

BACKGROUND: Abdominal bracing is effective in strengthening the trunk muscles; however, assessing performance can be challenging. We created a device for performing abdominal trunk muscle exercises. The effectiveness of this device has not yet been evaluated or compared OBJECTIVE: We aimed to quantify muscle activity levels during exercise using our innovative device and to compare them with muscle activation during abdominal bracing maneuvers. METHODS: This study included 10 men who performed abdominal bracing exercises and exercises using our device. We measured surface electromyogram (EMG) activities of the rectus abdominis (RA), external oblique, internal oblique (IO), and erector spinae (ES) muscles in each of the exercises. The EMG data were normalized to those recorded during maximal voluntary contraction (%EMGmax). RESULTS: During the bracing exercise, the %EMGmax of IO was significantly higher than that of RA and ES (p< 0.05), whereas during the exercises using the device, the %EMGmax of IO was significantly higher than that of ES (p< 0.05). No significant difference was observed in the %EMGmax of any muscle between bracing exercises and the exercises using the device (p= 0.13–0.95). CONCLUSIONS: The use of our innovative device results in comparable activation to that observed during abdominal bracing.


1992 ◽  
Vol 36 (10) ◽  
pp. 752-756
Author(s):  
Steven A. Lavender ◽  
Yang-Hwei Tsuang ◽  
Gunnar B.J. Andersson

The present investigation describes the electromyographic (EMG) response of eight trunk muscles during the application of loads to the torso while subjects maintained a twisted posture. The external moments of 20 and 40 Nm were applied to a harness system as each of the 10 subjects twisted 25 degrees. The applied moment direction was varied in 3 0 degree increments completely around the subjects (0 to 33 0 degrees). Surface EMG was used to monitor the left and right Latissimus Dorsi, Erector Spinae, External Oblique, and Rectus Abdominus. Multivariate and univariate analyses of variance (MANOVA and ANOVA) procedures showed significant main effects for all muscles and a significant moment magnitude by moment direction interaction effect in 6 of the 8 muscles. The greatest muscle activity was observed in the right Erector Spinae and the left External Oblique muscles. The results are also compared with an earlier study in which a similar loading paradigm was used as subject maintained a neutral upright posture.


Author(s):  
Sang-Yeol Lee ◽  
Se-Yeon Park

BACKGROUND: Recent clinical studies have revealed the advantages of using suspension devices. Although the supine, lateral, and forward leaning bridge exercises are low-intensity exercises with suspension devices, there is a lack of studies directly comparing exercise progression by measuring muscular activity and subjective difficulty. OBJECTIVE: To identify how the variations in the bridge exercise affects trunk muscle activity, the present study investigated changes in neuromuscular activation during low-intensity bridge exercises. We furthermore explored whether the height of the suspension point affects muscle activation and subjective difficulty. METHODS: Nineteen asymptomatic male participants were included. Three bridge exercise positions, supine bridge (SB), lateral bridge (LB), forward leaning (FL), and two exercise angles (15 and 30 degrees) were administered, thereby comparing six bridge exercise conditions with suspension devices. Surface electromyography and subjective difficulty data were collected. RESULTS: The rectus abdominis activity was significantly higher with the LB and FL exercises compared with the SB exercise (p< 0.05). The erector spinae muscle activity was significantly higher with the SB and LB exercises, compared with the FL exercise (p< 0.05). The LB exercise significantly increased the internal oblique muscle activity, compared with other exercise variations (p< 0.05). The inclination angle of the exercise only affected the internal oblique muscle and subjective difficulty, which were significantly higher at 30 degrees compared with 15 degrees (p< 0.05). CONCLUSIONS: Relatively higher inclination angle was not effective in overall activation of the trunk muscles; however, different bridge-type exercises could selectively activate the trunk muscles. The LB and SB exercises could be good options for stimulating the internal oblique abdominis, and the erector spinae muscle, while the FL exercise could minimize the erector spinae activity and activate the abdominal muscles.


2006 ◽  
Vol 86 (5) ◽  
pp. 656-671 ◽  
Author(s):  
Rafael F Escamilla ◽  
Eric Babb ◽  
Ryan DeWitt ◽  
Patrick Jew ◽  
Peter Kelleher ◽  
...  

Abstract Background and Purpose. Performing nontraditional abdominal exercises with devices such as abdominal straps, the Power Wheel, and the Ab Revolutionizer has been suggested as a way to activate abdominal and extraneous (nonabdominal) musculature as effectively as more traditional abdominal exercises, such as the crunch and bent-knee sit-up. The purpose of this study was to test the effectiveness of traditional and nontraditional abdominal exercises in activating abdominal and extraneous musculature. Subjects. Twenty-one men and women who were healthy and between 23 and 43 years of age were recruited for this study. Methods. Surface electromyography (EMG) was used to assess muscle activity from the upper and lower rectus abdominis, external and internal oblique, rectus femoris, latissimus dorsi, and lumbar paraspinal muscles while each exercise was performed. The EMG data were normalized to maximum voluntary muscle contractions. Differences in muscle activity were assessed by a 1-way, repeated-measures analysis of variance. Results. Upper and lower rectus abdominis, internal oblique, and latissimus dorsi muscle EMG activity were highest for the Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees. External oblique muscle EMG activity was highest for the Power Wheel (pike, knee-up, and roll-out) and hanging knee-up with straps. Rectus femoris muscle EMG activity was highest for the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up. Lumbar paraspinal muscle EMG activity was low and similar among exercises. Discussion and Conclusion. The Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees not only were the most effective exercises in activating abdominal musculature but also were the most effective in activating extraneous musculature. The relatively high rectus femoris muscle activity obtained with the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up may be problematic for some people with low back problems.


Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6646
Author(s):  
Jacqueline Toner ◽  
Jeremy Rickards ◽  
Kenneth Seaman ◽  
Usha Kuruganti

Previous research identifies that pushing and pulling is responsible for approximately 9–18% of all low back injuries. Additionally, the handle design of a cart being pushed can dramatically alter a worker’s capacity to push (≅9.5%). Surprisingly little research has examined muscle activation of the low back and its role in muscle function. Therefore, the purpose of this study was to examine the effects of handle design combination of pushing a platform truck cart on trunk muscle activity. Twenty participants (10 males and 10 females, mean age = 24.3 ± 4.3 years) pushed 475 lbs using six different handle combinations involving handle orientation (vertical/horizontal/semi-pronated) and handle height (hip/shoulder). Multichannel high-density EMG (HDsEMG) was recorded for left and right rectus abdominis, erector spinae, and external obliques. Pushing at hip height with a horizontal handle orientation design (HH) resulted in significantly less (p < 0.05) muscle activity compared to the majority of other handle designs, as well as a significantly higher entropy than the shoulder handle height involving either the semi-pronated (p = 0.023) or vertical handle orientation (p = 0.028). The current research suggests that the combination of a hip height and horizontal orientation handle design may require increased muscle demand of the trunk and alter the overall muscle heterogeneity and pattern of the muscle activity.


2021 ◽  
Author(s):  
Nika Zolfaghari

The study of seated balance, specifically for the application of wheelchair users, has been an area of interest for quite some time. Unfortunately, most of the available studies to date have focused on upper limb and shoulder muscles, and little has been done analyzing the activity of trunk muscles (abdominal and back). For the purpose of this study, motorized rotational motion in the forward and backward directions at ±45 degrees was simulated, and the corresponding trunk muscle activity of nine healthy subjects was recorded by surface electromyography (EMG) for eight muscles, including an analysis on the effect of holding on to a harness for support, coupled with the presence of a visual input. The collected raw data was filtered, and the produced results illustrated that the muscle activity was greatest in the forward rotational direction, when the subject was holding on to a harness for support, with visuals present.


Author(s):  
Kazuma Uebayashi ◽  
Yu Okubo ◽  
Takuya Nishikawa ◽  
Taro Morikami ◽  
Jindo Hatanaka

BACKGROUND: Given the characteristics of the superficial trunk muscles that cross the chest and pelvis, their excessive contraction might limit chest mobility. OBJECTIVE: To examine the immediate effects of two types of trunk muscle exercises on chest mobility and trunk muscle activities. METHODS: Fourteen healthy men (age: 21.1 ± 1.0 years, height: 172.7 ± 5.6 cm, weight: 61.0 ± 7.1 kg, body mass index: 20.4 ± 1.7 kg/m2; mean ± SD) randomly performed trunk side flexion and draw-in exercises using a cross-over design. The chest kinematic data and trunk muscle activities were measured before and after each intervention during the following tasks: maximum inspiration/expiration and maximum pelvic anterior/posterior tilt while standing. Two-way repeated measures analysis of variance was used for statistical analysis (P< 0.05). RESULTS: After the side flexion, upper and lower chest mobility significantly decreased, and superficial trunk muscle activity significantly increased during the maximum pelvic anterior tilt (P< 0.05). Additionally, after the draw-in, upper chest mobility significantly increased during the maximum pelvic anterior tilt (P< 0.05). CONCLUSIONS: Increased activity of the superficial abdominal muscles might limit chest mobility during maximum pelvic anterior tilt. Conversely, the facilitation of deep trunk muscles might increase upper chest mobility during the maximum pelvic anterior tilt.


2002 ◽  
Vol 205 (13) ◽  
pp. 1953-1967 ◽  
Author(s):  
Stephen M. Deban ◽  
David R. Carrier

SUMMARYThe axial muscles of terrestrial vertebrates serve two potentially conflicting functions, locomotion and lung ventilation. To differentiate the locomotor and ventilatory functions of the hypaxial muscles in mammals, we examined the locomotor and ventilatory activity of the trunk muscles of trotting dogs under two conditions: when the ventilatory cycle and the locomotor cycle were coupled and when they were uncoupled. Patterns of muscle-activity entrainment with locomotor and ventilatory events revealed (i)that the internal and external abdominal oblique muscles performed primarily locomotor functions during running yet their activity was entrained to expiration when the dogs were standing, (ii) that the internal and external intercostal, external oblique thoracic and transversus abdominis muscles performed both locomotor and respiratory functions simultaneously, (iii) that the parasternal internal intercostal muscle performed a primarily respiratory function (inspiration) and (iv) that the deep pectoralis and longissimus dorsi muscles performed only locomotor functions and were not active while the dogs were standing still. We conclude that the dual function of many hypaxial muscles may produce functional conflicts during running. The redundancy and complexity of the respiratory musculature as well as the particular pattern of respiratory—locomotor coupling in quadrupedal mammals may circumvent these conflicts or minimize their impact on respiration.


Author(s):  
Corina Nüesch ◽  
Jan-Niklas Kreppke ◽  
Annegret Mündermann ◽  
Lars Donath

Employing dynamic office chairs might increase the physical (micro-) activity during prolonged office sitting. We investigated whether a dynamic BioSwing® chair increases chair sway and alters trunk muscle activation. Twenty-six healthy young adults performed four office tasks (reading, calling, typing, hand writing) and transitions between these tasks while sitting on a dynamic and on a static office chair. For all task-transitions, chair sway was higher in the dynamic condition (p < 0.05). Muscle activation changes were small with lower mean activity of the left obliquus internus during hand writing (p = 0.07), lower mean activity of the right erector spinae during the task-transition calling to hand writing (p = 0.036), and higher mean activity of the left erector spinae during the task-transition reading to calling (p = 0.07) on the dynamic chair. These results indicate that an increased BioSwing® chair sway only selectively alters trunk muscle activation. Adjustments of chair properties (i.e., swinging elements, foot positioning) are recommended.


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