Effect of verbal instructions on trunk muscle activity during volitional preemptive abdominal contraction.

OBJECTIVE: This study investigated the effect of Verbal Instruction (VI) strategies on trunk muscle contraction among healthy subjects. The effect of three VI Abdominal Drawing-In Maneuver (ADIM) and two VI Abdominal Bracing Maneuver (ABM) strategies on left Internal (LIO) and External Oblique (LEO) and bilateral superficial Multifidi (sMf) activation was examined. DESIGN: Within-subjects, repeated measure design. METHODS: Surface EMG (sEMG) measured LIO, LEO, and sMf activity in 28 subjects (mean age 23.5 ± 5.5 years). Testing included five supine hook-lying and five quiet standing conditions. RESULTS: One-way ANOVAs demonstrated no significant main effect for ADIM or ABM in supine or standing (p > .05). Muscle activation amplitudes during VPAC conditions demonstrated higher mean values for standing versus supine (p < .05) except for two conditions involving LEO. Friedman Tests for dominant strategy demonstrated a significant main effect for ADIM-VI and ABM-VI strategies. Post-hoc testing generally showed the dominant strategy to be significantly higher versus others. CONCLUSION: No single preferred VI cue for ADIM or ABM was observed. Each subject's dominant strategy dictated the most suitable VI. Standing was preferred for LIO and sMf activation, whereas position did not change LEO activation. Non-significant correlations between all muscle pairings during all ADIM and ABM strategies were observed. These findings may suggest the need for healthcare providers who understand the intricacies of trunk stability to teach and monitor VPAC with either ADIM or ABM options.

Effects of mouthpiece shape and expiratory threshold loading on contraction of the lateral abdominal muscles: A cross-sectional study.

BACKGROUND: Expiratory tasks may facilitate transversus abdominis (TrA) activity for spinal stabilization. The purpose of this study was to verify whether a combination of pursed-lip breathing (PLB) and use of an expiratory threshold loading (ETL) device to increase expiratory resistance would promote TrA contraction comparable to that for a stabilization exercise. METHODS: Twenty healthy men performed expiratory tasks or an abdominal drawing-in maneuver (ADIM). Expiratory tasks comprised combinations of ETL settings with 0%, 5%, or 15% of maximum expiratory pressure, and mouthpieces with a normal shape or pursed-lip shape. B-mode ultrasound imaging of the TrA, internal oblique, and external oblique muscles was performed to determine percentage changes in muscle thickness. Percentage changes among tasks were statistically compared for each muscle. FINDINGS: TrA thickness increased with normal lips at 15% ETL, with PLB with 5% ETL, and with ADIM (p < 0.01 each). Internal oblique thickness increased under all PLB conditions (p < 0.01 each). No significant differences in external oblique thickness were seen for any tasks. The total thickness of the lateral abdominal muscles was significantly increased not only for 15% ETL tasks and ADIM, but also for PLB with 5% ETL (p < 0.02 each). INTERPRETATION: These results indicated that PLB with 5% ETL could facilitate the same level of TrA activity as the ADIM. PLB with 5% ETL was the only task that simultaneously increased overall lateral abdominal muscles, including the internal obliques, and might be readily applicable in clinical situations.

Comparison of linea alba length and core-muscles engagement during core and lower back orientated exercises.

BACKGROUND: A comparison of Linea Alba (LA) length and engagement of the Transverse Abdominis (TrA), External Oblique (EO) and Internal Oblique (IO) between core-orientated and lower back orientated exercises (e.g. glute bridge and hip extension) is lacking. Therefore, the aim of this study was to compare the length of the LA and the engagement of TrA, EO and IO when performing the prone plank, bird dog, dead bug, lateral plank, glute bridge and hip extension. METHODS: Thirteen apparently healthy participants volunteered to this study. Ultrasound scanning of the anterior and antero-lateral abdominal walls at baseline and whilst performing prone plank, bird dog, dead bug, lateral plank, glute bridge and hip extension exercises was performed. LA length and thickness of the TrA, EO and IO were measured from ultrasound images. RESULTS: LA length (p = 0.77) and TrA thickness (p = 0.23) were not different between exercises. EO thickness was larger for the lateral plank compared to the bird dog (p = 0.01, d = 1.73), glute bridge (p < 0.01, d = 2.64), and hip extension (p < 0.01, d = 1.89). The dead bug was also larger in comparison to the glute bridge (p < 0.01, d = 2.05) and to the hip extension (p = 0.01, d = 1.45). For the IO thickness, the lateral plank was larger than the bird dog (p = 0.03, d = 1.21) and the dead bug (p = 0.04, d = 1.12). CONCLUSION: No difference was observed between exercises for the length of the LA or for the thickness of the TrA, which suggests that this muscle is similarly engaged in the assessed exercises, leading to a consistent stretch for the LA.

Repeatability and reproducibility of the pressure biofeedback unit.

INTRODUCTION: Although the pressure biofeedback unit (PBU) is used for muscular assessment and training, there is little evidence of its reproducibility and repeatability. OBJECTIVE: This study aims to assess intra- and inter-rater reproducibility and repeatability of the PBU in the assessment of the transverse abdominal (TrA), internal oblique (IO), low back multifidi, and deep neck flexors (DNF). METHODS: Fifty individuals had three muscular groups tested: TrA/IO, lower back multifidi, and DNF. For repeatability, one rater did three consecutive measures; for intra-rater reproducibility the same rater did two measures with seven-day intervals, and for inter-rater reproducibility, three raters, on the same day, did the measures. Data were analyzed with: Intraclass Correlation Coefficient (ICC), Standard Error of Measurement (SEM), and Minimal Detectable Change (MDC). (α = 0,05). RESULTS: Repeatability: TrA/IO (ICC = 0.847), Multifidi (ICC = 0.860), DNF (ICC = 0.831). Inter-rater reproducibility: TrA/IO (ICC = 0.876), Multifidi (ICC = 0.508), DNF (ICC = 0.442). Intra-rater reproducibility: TrA/IO (ICC = 0.747), Multifidi (ICC = 0.293), DNF (ICC = 0.685). Except for Multifidi, all the SEM values were less than 10 mmHg and the MDC values were less than 15 mmHg. CONCLUSIONS: The PBU can be used with reliability by different evaluators, although the evaluation of multifidi is not indicated.

Effect of whole body vibration on the electromyographic activity of core stabilizer muscles: WBV ON CORE STABILIZER MUSCLES.

OBJECTIVE: To analyze the effects of whole body vibration on electromyographic activity of the core muscles. METHODS: This is an observational cross-sectional study composed of 30 males who practice physical activity. The amplitude of the electromyographic activation (Root Mean Square - RMS) of the rectus abdominis, external oblique, longissimus thoracis, multifidus muscles were evaluated during supine bridge, side plank and frontal plank exercises, performed with and without vibration (frequency: 50 Hz and amplitude: 4 mm). A significance level of 5% was assigned for all analyzes. RESULTS: Whole body vibration did not alter the amplitude of electromyographic activity for any of the evaluated muscle groups, showing no difference between the conditions with and without vibration during the performance of the proposed exercises. CONCLUSION: Under the conditions analyzed in this study, the vibrating platform does not change the activation amplitude of core muscles, suggesting that the use of whole body vibration is not necessary as an additional method to increase muscle activity during stabilization exercises in healthy men.

Core muscle activation during Pilates exercises on the Wunda chair.

OBJETIVES: The Pilates method, developed by Joseph Pilates (1886-1967), has been widely used to improve trunk stability, muscle flexibility and strength, physical fitness, and body awareness. To measure the electromyography of four trunk muscles during three Pilates exercises carried out of the wunda chair. DESING: cross-section study. METHODS: Sixteen women participated in this study with a height and body weight of 1.64 ± 0.04 m and 58.7 ± 7.4 kg, respectively, and a mean age of 27.6 ± 3.7 years. Rectus abdominis (RA), internal oblique (IO), longissimus (LO), and multifidus (MU) muscles was evaluated by electromyographic (EMG) tests activity during three Pilates exercises: going up front (GF), mountain climb (MC), and swan (SW). EMG was normalized and expressed in the time domain, by the RMS. RESULTS: The highest EMG values concerning the four muscles were observed for the MC exercise, followed by GF and SW (ANOVA: p = 0.0001, p = 0.04, p = 0.0002, and p = 0.0013, respectively). Our results show that the three Pilates exercises could recruit all the muscles, with a moderate activity intensity. The ANOVA; p < 0.05 showed significant difference between the muscles, concerning SW (p = 0.0002). CONCLUSION: Our results show that the three Pilates exercises could recruit all the muscles, with a moderate activity intensity.

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

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.

Electromyographic evaluation of trunk core muscles during Pilates exercise on different supporting bases.

OBJECTIVE: To evaluate the electromyographic (EMG) activity of the rectus abdominis (RA) and internal oblique (IO) muscles during Pilates exercise on different trunk supporting bases. METHODS: Sixteen female Pilates practitioners participated in the study. EMG of the RA and OI muscles was evaluated during the double leg stretch (DLS) exercise on three different supporting bases - mat, long box, and short box. Trunk stability varies according to the size and type of the base. To normalize the data, the RMS value (EMG) obtained during the DLS exercise was divided by the RMS value from the torque test - the maximal voluntary isometric contraction (MVIC) - and multiplied by 100 (%MVIC). One-way repeated-measured analysis of variance (ANOVA) and Bonferroni tests were used to compare data concerning the supporting bases and Student t-test regarding the muscles (p < 0.05). RESULTS: The comparison among the bases involving each muscle - RA or IO (p < 0.05) - showed significant difference (%MVIC) between the mat and the short box. No significant difference was observed between the muscles concerning the exercise on the mat (p = 0.9266), on the long box (p = 0.5113) and on the short box (p = 0.2972). CONCLUSION: The short box increased the activity of the rectus abdominis and internal oblique muscles during exercise. The DLS exercise was able to challenge the stability of the trunk and thus recruit its stabilizer and mobilizer muscles at the same intensity.

Overflow using proprioceptive neuromuscular facilitation in post-stroke hemiplegics: A preliminary study.

Hemiplegia is the classic condition resulting from a stroke. To assist in recovery, the overflow method can be employed to stimulate the affected limb, using the healthy contralateral lower limb (LL) to activate the plegic upper limb (UL) musculature. The aim of this study was to evaluate the immediate effect of overflow using the PNF method on the plegic upper limb muscles of post-stroke individuals in the acute and chronic stages, as well as on the muscles of healthy individuals. A total of 22 individuals participated in the work, comprising 8 healthy individuals (control group), 6 post-stroke acute stage individuals (acute group), and 8 post-stroke chronic stage individuals (chronic group). The participants were assessed using a questionnaire with sections for personal and disease data and application of the ICF scale and the Fugl-Meyer index. The three groups were submitted to electromyographic evaluation, using the posterior deltoid (PD), anterior deltoid (AD), pectoralis major (PM), and external oblique (EO) muscles in four different positions: P1 (resting the UL, with the LL contralateral to the affected limb positioned in diagonal); P2 (resting the UL, with manual resistance in the contralateral LL); P3 (affected UL positioned in diagonal, with manual resistance in the contralateral LL) e P4 (affected UL positioned in diagonal, with fixed point and manual resistance in the contralateral LL). The electromyography results revealed no significant differences between most of the positions for the four muscles evaluated (p > 0.05). However, high clinical relevance (d > 0.8) was found for muscle activation in positions 2 and 4. It could be concluded that for post-stroke individuals in the acute and chronic stages, overflow using PNF effectively increased activation of the PD, AD, PM, and EO muscles in the P2, as well as position 4.

Dry needling in chronic abdominal wall pain of uncertain origin.

BACKGROUND: Abdominal wall pain is considered as pain that arises from the abdominal muscles rather than the underlying viscera or the spine. It is frequently overlooked and is often misdiagnosed, as these patients continue to suffer with pain. Many such patients would have even been subjected to a psychiatric evaluation in view of the absence of any ostensible clinical cause for the pain. In this study, we describe the role of myofascial trigger points in the abdominal wall pain that could be a cause of chronic pain and present our findings of pain relief by dry needling technique. OBJECTIVES: To report the effect of dry needling treatment for patients who suffer from chronic abdominal wall pain of uncertain etiology and in whom specific myofascial trigger points were identified. METHODS: Twelve patients diagnosed with chronic abdominal wall pain were included in the study. All patients were clinically evaluated and subjected to a combination of imaging techniques. Once categorized as patients suffering from chronic abdominal wall pain, they were subjected to a thorough palpation of the abdominal wall to identify the presence of myofascial trigger points (MTrPs) over the abdominal muscles. All had MTrPs over one or more abdominal muscles either unilaterally or bilaterally. Dry Needling using a standard technique was done based on the side and localization of the myofascial trigger points. Numerical pain rating scale (NPRS) was used to measure pain before and after treatment and at the end of four months. All patients were then seen by the primary clinician and re-evaluated. RESULTS: Eleven out of twelve patients had significant reduction with a mean difference 5.95 in NPRS in their pain levels at four months follow up. Seven patients had complete resolution of the pain. Some patients had improvement in complaints such as Dysmenorrhea, Urinary Frequency and constipation. CONCLUSION: Dry Needling can be a useful adjunct in treating chronic abdominal wall pain especially in those patients in whom Myofascial Trigger Points in the muscles of abdomen are identified by palpation. LEVEL OF EVIDENCE: Level 4.

Comparison between the Ki-hap technique and verbal encouragement on activation of abdominal muscles in healthy participants.

The aim of this study was to investigate the comparison between a Ki-hap, defined as a psyching-up technique, and verbal encouragement, defined as a verbal command by a third party, on abdominal muscle activation during performance of the crunch exercise in healthy participants. Ninety participants were randomly allocated to the following three groups: crunch only exercise group (CG, n1 = 30), crunch exercise with Ki-hap group (CKG, n2 = 30), and crunch exercise with Ki-hap and verbal encouragement group (CKVG, n3 = 30). The interventions were conducted over three trials with each group, and measurements involving each participant, were performed by a single examiner. The activation of the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles were evaluated using electromyography (EMG) during performance of the crunch exercise by the CG, CKG, and CKVG. Our results showed a significantly greater increase in the EMG patterns of all muscles during performance of the crunch exercise in the CKG (p < 0.05) compared to those in the CG and CKVG. The results also showed that there was a significantly greater increase in the activation of the EO and IO muscles in the CKVG (p < 0.05) compared with that in the CG. These findings demonstrated that the addition of the Ki-hap technique and verbal encouragement, during performance of the crunch exercise, improves activation of the abdominal muscles.

Pilates instruction affects stability and muscle recruitment during the long stretch exercise.

PURPOSE: To examine pelvic stability with and without instruction regarding the voluntary recruitment of the 'powerhouse' muscles during a long stretch exercise on the Pilates Reformer. SCOPE: Evaluation of the muscle activity and pelvic stability during a Pilates exercise of 12 physically active volunteers. Volunteers performed five repetitions of the long stretch in sets of two, one with and one without instruction regarding the voluntary recruitment of the powerhouse muscles. Electromyography of the external oblique (EO), multifidus (MU), gluteus maximus (GM) and adductor longus (AL) muscles and pelvic angle stability were recorded. CONCLUSION: When asked to perform the exercise with instruction regarding the voluntary recruitment of the powerhouse muscles, all muscles were more activated, with the exception of the EO. In the voluntary recruitment situation, lumbopelvic stability, as measured by the coefficient of variation of the pelvic angle, was higher than in instances without instruction. Lumbopelvic stability undergoes changes with and without instruction regarding the voluntary recruitment of the powerhouse muscles when the long stretch exercise is performed on a Reformer.

Electromyographic activities of the abdominal muscles during 30% and 75% of maximum expiratory pressure.

The aim of this study was to quantify the activities of the rectus abdominis (RA), external oblique (EO), and internal oblique (IO) muscles during 30% and 75% of maximum expiratory pressure (PE max). Fifteen healthy male university students participated in this study. Electromyographic (EMG) activities of the RA, EO, and IO muscles were measured during 30% and 75% of PE max and then normalized relative to maximum voluntary contractions (%MVC). All muscles during 75% of PE max showed significantly higher %MVC compared to that during 30% of PE max (P < 0.01). The EO and IO muscles showed significantly higher %MVC compared to the RA muscle during 30% and 75% of PE max (P < 0.05). Muscle endurance and strength induced by expiratory muscle strength training might be different in each abdominal muscle.

Abdominal muscle activity during breathing in different postural sets in healthy subjects.

OBJECTIVE: This study aims to evaluate the effect of different postural sets on abdominal muscle activity during breathing in healthy subjects. METHODS: Twenty-nine higher education students (20.86 ± 1.48 years; 9 males) breathed at the same rhythm (inspiration: 2 s; expiration: 4 s) in supine, standing, tripod and 4-point-kneeling positions. Surface electromyography was performed to assess the activation intensity of rectus abdominis, external oblique and transversus abdominis/internal oblique muscles during inspiration and expiration. RESULTS: During both breathing phases, the activation intensity of external oblique and transversus abdominis/internal oblique was significantly higher in standing when compared to supine (p ≤ 0.001). No significant differences were found between tripod position and 4-point-kneeling positions. Transversus abdominis/internal oblique activation intensity in these positions was higher than in supine and lower than in standing. CONCLUSIONS: Postural load and gravitational stretch are factors that should be considered in relation to the specific recruitment of abdominal muscles for breathing mechanics.

Effects of Weight-shifting Exercise Combined with Transcutaneous Electrical Nerve Stimulation on Muscle Activity and Trunk Control in Patients with Stroke.

This study investigated the effects of weight-shifting exercise (WSE) combined with transcutaneous electrical nerve stimulation (TENS), applied to the erector spinae and external oblique (EO) muscles, on muscle activity and trunk control in patients with hemiparetic stroke. Sixty patients with stroke were recruited to this study and randomly distributed into three treatment groups: (1) WSE + TENS, (2) WSE + placebo TENS, and (3) control. All participants underwent 30 sessions of training (30 minutes five times per week for 6 weeks) and received 1 hour of conventional physical therapy five times per week for 6 weeks. Muscle activity, maximum reaching distance and trunk impairment scale scores were assessed in all patients before and after the training. After training, the WSE + TENS group showed significant increase in the EO activity, maximum reaching distance and trunk impairment scale scores compared with the WSE + placebo TENS and control groups. These findings suggest that WSE with TENS applied to the erector spinae and EO muscles increased the trunk muscle activity and improved trunk control. Therefore, WSE with TENS could be a beneficial intervention in clinical settings for individuals with hemiparetic stroke. Copyright © 2016 John Wiley & Sons, Ltd.