Trunk muscle activation in prone plank exercises with different body tilts

BACKGROUND

Body tilt changes could affect the intensity/difficulty of core stability exercises, but there is still a lack of knowledge about its impact.

OBJECTIVE

To analyse the trunk muscles activation during prone plank exercises at different body tilts.

METHODS

Twenty-four young adults who performed recreational gymnastic activities participated in this study. Electromyography activity of the rectus abdominis (RA), external oblique (EO), internal oblique (IO) and erector spinae (ES) was recorded during the performance of six variations of the prone plank exercise (planking with feet supported on the ground [conventional horizontal position] and planking with feet supported on wall bars at five different heights increasing the angle tilt) and an inverted position exercise.

RESULTS

The RA, EO and IO activation in all prone plank variations were higher than those observed in the conventional prone plank. In addition, the coefficient of variation of the muscle activation increased with the declination angle, reaching the highest values in the inverted position for the RA and ES muscles.

CONCLUSION

The results seem to indicate that the body tilt variation could be used as an easy and inexpensive strategy for modulating the neuromuscular demands and the motor control challenge during planking exercises.

Neutral posture education during cough can reduce urine leakage in women with cough-related stress urinary incontinence

BACKGROUND

Current literature highlights the difficulty in identifying an optimal educational technique for maintaining continence during cough.

OBJECTIVE

To characterize the effects of an educational intervention focusing on neutral posture during cough in women with cough-induced urinary incontinence (UI).

METHODS

This interventional study design included women with cough-induced UI. We recorded PFMs surface electromyographic (sEMG) peak activity, and assessed symptoms and quality of life (QoL) 6 weeks after the intervention. The effect of the experimental situation was estimated using a linear mixed model, sEMG measurements during coughing were indexed to each situation and adjusted to the resting value at, and a moderation analysis was used.

RESULTS/FINDINGS

Eighteen participants were included. The measurement situations (control versus experimental) did not have a statistically significant impact on sEMG peak activity during coughing: mean effect [95% CI] 3.42 [-1.28; 7.66]. Six weeks post-intervention, participants reported statistically significant decrease in urinary symptoms (P=0.0246) and significant improvement in QoL (P=0.00776). This was also particularly marked on the dimension related to effort activities (P=0.00162).

CONCLUSION

This study suggests that a brief educational intervention focusing on neutral posture during cough, without voluntary pre-contraction of the PFMs, has no clinically significant influence on sEMG peak activity of the PFMs in women with cough-induced UI. However, this intervention can lead to a significant improvement in urinary symptoms and QoL at 6 weeks. These improvements seem to be independent of electromyographic PFMs peak activity recorded during cough. As such, our preliminary results pave the way for future research.

LEVEL OF EVIDENCE

NP4.

Scapula winging secondary to prone plank exercise: a case report

Background: Scapular winging occurs when the muscles responsible for the stabilization of the scapula (serratus anterior, trapezius, rhomboid major and minor) are paralyzed due to any reason. The most frequently observed neurological aetiology is serratus anterior muscle dysfunction due to long thoracic nerve palsy. The cause of long thoracic nerve palsy may be traumatic or atraumatic. It has been previously reported that a wide variety of sports can cause long thoracic nerve palsy.Clinical presentation: In this article, we report a case of unilateral winging of the scapula due to injury to the long thoracic nerve which occurred secondary to performing prone plank exercises; the likes of which has not previously been described in the literature and which may have occurred due to the exercise being performed incorrectly. In this patient, nerve recovery became evident one month following conservative treatment and cessation of plank exercises.Conclusion: Long thoracic nerve injury may have occurred due to increased and incorrect scapula loading during plank exercises. In order to prevent compression neuropathies caused by load transfer imbalance, attention should be paid to correct positioning whilst performing core stabilization exercises such as the prone plank.

Optimizing normalization methods of the external oblique: A cross-sectional study

BACKGROUND

Adequate normalization methodology to establish maximum voluntary isometric contraction (MVIC) is needed to compare %MVIC values for core exercise completed until discontinuation. Clinicians can use %MVIC classifications to guide their preventative and rehabilitative exercise interventions.

OBJECTIVE

The aim of this study was to compare %MVIC of the external oblique (EO) between normalization techniques of side-lying lateral trunk flexion and Roman chair lateral trunk flexion.

METHODS

Twenty-two participants completed two MVIC techniques followed by one repetition of the prone bridge plank (PBP), torso elevated side plank (TESP), foot elevated side plank (FESP), dead bug and bird dog. The average %MVIC during the first 5-seconds, last 5-seconds and overall duration of exercise were included for analysis. ANOVA was used to compare normalized %MVIC from each of the 5 exercises between MVIC techniques. Alpha set a priori p= 0.05.

RESULTS

The side-lying table technique yielded no %MVIC values above 100%, while the Roman chair technique produced 7 values above 100%. The largest mean difference between techniques was during the last 5-seconds of the torso elevated side plank (57.87 ± 38.51%MVIC, p< 0.001).

CONCLUSION

The side-lying table technique likely provides the optimal methodology of %MVIC determination.

Effects of a 6 week core strengthening training on measures of physical and athletic performance in adolescent male sub-elite handball players

The objective was to investigate the effects of a 6-week core strengthening training within the regular handball training sessions compared to regular handball training only. Male sub-elite handball players were randomly assigned to an intervention (INT: n = 13; age: 16.9 ± 0.6 years) or a control (CON: n = 13; age: 17.2 ± 0.8 years) group. The INT group performed the "big 3" core exercises cross curls-up, side bridge (both sides), and the quadrupedal stance ("birddog exercise") triweekly for 20-30 min while the CON group conducted regular handball training only. Pre- and post-training assessments included measures of muscular endurance (Closed Kinetic Chain Upper Extremity Stability Test [CKCUEST] and the Bourban test), shoulder mobility/stability (Upper Quarter Y Balance [YBT-UQ] test), and throwing velocity. The ANCOVA revealed significant differences between means in favour of the INT group for the dorsal chain (p < 0.001,η p 2 = 0.46) and the lateral chain (left side: p = 0.015,η p 2 = 0.22; right side: p = 0.039,η p 2 = 0.17) of the Bourban test, the composite score (p = 0.024,η p 2 = 0.20) of the throwing arm reach and the inferolateral reach direction (p = 0.038,η p 2 = 0.17), and the composite score (p = 0.027,η p 2 = 0.19) of the non-throwing arm reach of the YBT-UQ. However, performance in the CKCUEST and throwing velocity did not show any group-specific changes. Therefore, 6 weeks of core strengthening training were effective in improving some components of physical but no handball-specific athletic (i.e., throwing velocity) performance in adolescent male sub-elite handball players. Practitioners may still opt for this training regimen when stimulus variability is sought or when a low load/low movement approach (e.g., during rehabilitation) is favoured.

The deer play in Wuqinxi and four-point hand−knee kneeling positions for training core muscle function and spinal mobility

The four-point kneeling exercise is a core stabilization exercise that provides the spine with dynamic stability and neuromuscular control. In the traditional Chinese exercise Wuqinxi, deer play is performed in a hand−foot kneeling (HFK) position, which is remarkably similar to the four-point hand−knee kneeling (HKK) position. However, the differences in spinal function promotion between these two positions are poorly understood. The aim of this study was to investigate muscle activation patterns and spinal kinematics during specific core stabilization training to provide evidence for selecting specific exercises. A total of 19 healthy adults were recruited to perform HFK and HKK. The rotation angle of the C7–T4 vertebra and the surface EMG signals of abdominal and lumbar muscles on both sides were collected. The paired t-test showed that the vertebral rotation angles were significantly higher during HKK than HFK, and the intra-group differences mainly occurred at the level of the thoracic vertebra. The muscle activation of both sides of the rectus abdominis and external oblique in HFK was significantly higher than in HKK when the upper limb was lifted (p < 0.05). The activation of the ipsilateral lumbar multifidus and erector spinae muscles was significantly higher during the HKK position than during HFK when the lower limb was lifted (p < 0.05). HFK provided more training for strengthening abdominal muscles, while HKK could be recommended for strengthening lumbar muscles and increasing spine mobility. These findings can be used to help physiotherapists, fitness coaches, and others to select specific core exercises and develop individualized training programs.

Classification of Plank Techniques Using Wearable Sensors

The plank is a common core-stability exercise. Developing a wearable inertial sensor system for distinguishing between acceptable and aberrant plank techniques and detecting specific deviations from acceptable plank techniques can enhance performance and prevent injury. The purpose of this study was to develop an inertial measurement unit (IMU)-based plank technique quantification system. Nineteen healthy volunteers (age: 20.5 ± 0.8 years, BMI: 22.9 ± 1.4 kg/m²) performed the standard plank technique and six deviations with five IMUs positioned on the occiput, cervical spine, thoracic spine, sacrum, and right radius to record movements. The random forest method was employed to perform the classification. The proposed binary tree classification model achieved an accuracy of more than 86%. The average sensitivities were higher than 90%, and the specificities were higher than 91%, except for one deviation (83%). These results suggest that the five IMU-based systems can classify the plank technique as acceptable or aberrant with good accuracy, high sensitivity, and acceptable specificity, which has significant implications in monitoring plank biomechanics and enabling coaching practice.

Influence of Abdominal Hollowing Maneuver on the Core Musculature Activation during the Prone Plank Exercise

This cross-sectional study of repeated measures investigated whether integrating the abdominal hollowing maneuver (AHM) into the prone plank performance is an effective strategy for increasing both the activation of the deep and superficial core musculature. Electromyographical (EMG) responses of rectus abdominis (RA), external oblique (EO), internal oblique (IO), and lumbar erector spinae (LES), and ratings of perceived exertion (RPE) of 20 participants (13 male, 7 female; mean ± standard deviation (SD) age: 24.25 ± 3.54 years; body mass: 66.42 ± 8.40 kg; height: 1.70 ± 9.51 m) were compared across two experimental conditions: the traditional prone plank (STANDARD); and a variation including the AHM (HOLLOWING). Regarding Total Intensity, HOLLOWING resulted in significantly greater EMG response than STANDARD (p < 0.001; Effect size (ES) = 3.01). Specifically, RA showed no significant differences between STANDARD and HOLLOWING (p = 0.056; ES = 0.285). However, for the remaining analyzed muscles, HOLLOWING significantly provided higher EMG activation compared to STANDARD (LES: p = 0.004; ES = 0.619; left EO: p < 0.001; ES = 1.031; right EO: p < 0.001; ES = 1.419; left IO: p < 0.001; ES = 2.021; right IO: p < 0.001; ES = 2.269). Regarding RPE, HOLLOWING reported values significantly greater than STANDARD (p < 0.001; ES = 2.94). In conclusion, integrating the AHM into the prone plank exercise enhances overall abdominal activity, particularly in both obliques. These findings provide updated guidelines for lumbar stabilization and core strengthening in health-related physical fitness programs.

Core Muscle Activity During Physical Fitness Exercises: A Systematic Review

The aim of this study was to systematically review the current literature on the electromyographic (EMG) activity of six core muscles (the rectus abdominis, the internal and external oblique, the transversus abdominis, the lumbar multifidus, and the erector spinae) during core physical fitness exercises in healthy adults. A systematic review of the literature was conducted on the Cochrane, EBSCO, PubMed, Scopus, and Web of Science electronic databases for studies from January 2012 to March 2020. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used. The inclusion criteria were as follows: a) the full text available in English; b) a cross-sectional or longitudinal (experimental or cohorts) study design; c) the reporting of electromyographic activity as a percentage of maximum voluntary contraction (% MVIC), millivolts or microvolts; d) an analysis of the rectus abdominis (RA), transversus abdominis (TA), lumbar multifidus (MUL), erector spinae (ES), and the internal (IO) or external oblique (EO); e) an analysis of physical fitness exercises for core training; and f) healthy adult participants. The main findings indicate that the greatest activity of the RA, EO, and ES muscles was found in free-weight exercises. The greatest IO activity was observed in core stability exercises, while traditional exercises showed the greatest MUL activation. However, a lack of research regarding TA activation during core physical fitness exercises was revealed, in addition to a lack of consistency between the studies when applying methods to measure EMG activity.

Effect of the body mass index and sexual difference on the muscle activity during trunk exercise: a preliminary study

There was lack of study which evaluated the effects of characteristics of subjects such as the body mass index (BMI) or waist circumference (WC), as well as sexual differences on trunk muscle activities. The purpose of the present study was to compare the abdominal muscle activities among the groups dividing criterion as the BMI, WC, and the gender. As a criterion of BMI and WC, subjects were arranged to three groups. Female subjects who were less than 25 kg/m² BMI, and less than 90 WC were arranged as female with underweight group (FU), male subjects who were greater than 25 kg/m² BMI and greater than 85 WC were arranged as male with overweight group (MO), male subjects who were less than 25 kg/m² BMI and less than 85 WC were arranged in male with underweight group (MU). Surface electromyography responses of the rectus abdominis, internal oblique, external oblique muscles and lumbar level of erector spinae were obtained during the plank and maximal voluntary isometric contraction (MVIC). The MO group showed significantly higher %MVIC value of the internal oblique and lumbar level of erector spinae, compared to the MU group (P<0.05). The %MVIC of the rectus abdominis was significantly greater with the FU group (P<0.05). There were significant differences in the root mean squared (RMS) values from MVIC among the three groups (P<0.05). Regardless of muscles differences, the MO group showed significantly lower RMS activity values than the FU and the MU groups (P<0.05). Present study indicates some considerations of interpreting surface electromyography (sEMG) signal from region overlapping large fat tissue especially for trunk muscles. Individual characteristics such as gender, BMI, and WC could affect the sEMG signals. The female and male with overweight represent relatively high %MVICs during exercise, but it might be due to relatively low RMS values from procedure of MVICs.