Back and abdominal muscle function during stabilization exercises

Effects of unstable load and unstable surface ontrunk muscles activation and postural control in healthy subjects

Exercise with an unstable load is considered a new training method to activate the core muscles. Research has shown consistency regarding an unstable surface but has not provided comprehensive findings about the effect of an unstable load. The study aimed to examine the impact of an unstable load and unstable surfaces on core muscle activation and postural control during lifting. Thirty-eight participants lifted a load equivalent to 10 % of their body weight under three conditions: a stable load on an unstable surface, a stable load on a stable surface, and an unstable load on a stable surface. The center of pressure (COP) displacement and electromyography activity of abdominal and back extensor muscles were measured during lifting. The results indicated that lifting on an unstable surface activated the lumbar erector spinae and multifidus muscles more than in a stable condition (P<0.05). However, there was no significant difference in the level of thoracic erector spinae muscle activity between the unstable load and unstable surface conditions. The stable condition increased activity in the internal oblique muscle (1.37 times) compared to the unstable conditions. The analysis of postural control revealed that lifting the load on an unstable surface significantly decreased COP displacement in the anteroposterior direction (P<0.05), while holding the load on the unstable surface significantly increased COP displacement in the anteroposterior direction compared to the other conditions. These findings could be valuable for future rehabilitation research, learning appropriate lifting techniques, and setting specific training goals in sports.

Gamified delivery of at-home rehabilitation for individuals with nonspecific low back pain: a randomized controlled trial

PURPOSE

To measure the change in pain and disability during and after a 6-week gamified delivery of home exercise compared to a take-home packet.

MATERIALS AND METHODS

A 6-week at-home exercise protocol included participants randomly allocated to a gamified delivery group or packet group. The exercise protocol included the plank, side plank, foot elevated side plank, dead bug, and bird dog completed until discontinuation. The gamified delivery group received on-demand exercise videos and weekly exercise duration leaderboards. The packet group received a take-home packet.

RESULTS

Forty participants were randomized into a packet group and leaderboard group, and 30 participants completed the study. Disability was significantly lower at 6-weeks (11.29 ± 9.81%) compared to baseline (15.93 ± 11.65%) in the packet group (χ2(2) =10.89, Z= -3.163, p=.002, r=.708). Percent disability was significantly lower at 6-weeks (8.00 ± 5.91%) compared to baseline (13.01 ± 7.17%) in the gamified delivery group (χ2(2) =13.235, Z= -3.399, p= <.001, r= -0.760). Worst pain was higher at baseline (7.05 ± 1.61%) than at 6-weeks (5.75 ± 1.68%) in the packet group (χ2(2) =8.067, Z = 2.760, p=.006, r= -0.617). Worst pain was higher at baseline (6.90 ± 1.33%) than at 6-weeks (5.24 ± 2.38%) in the gamified delivery group (χ2(2) =6.250, Z= -2.810, p=.005, r= -0.628). No significant difference in the change of disability from baseline to 6 weeks was found between groups (p=.483).

CONCLUSIONS

Core exercises completed until failure may improve disability and pain at 6-weeks and positively influence perceived patient improvement.Registry: Clinicaltrials.gov; Registration number: NCT05573932.

The Application of Surface Electromyography Technology in Evaluating Paraspinal Muscle Function

Surface electromyography (sEMG) has emerged as a valuable tool for assessing muscle activity in various clinical and research settings. This review focuses on the application of sEMG specifically in the context of paraspinal muscles. The paraspinal muscles play a critical role in providing stability and facilitating movement of the spine. Dysfunctions or alterations in paraspinal muscle activity can lead to various musculoskeletal disorders and spinal pathologies. Therefore, understanding and quantifying paraspinal muscle activity is crucial for accurate diagnosis, treatment planning, and monitoring therapeutic interventions. This review discusses the clinical applications of sEMG in paraspinal muscles, including the assessment of low back pain, spinal disorders, and rehabilitation interventions. It explores how sEMG can aid in diagnosing the potential causes of low back pain and monitoring the effectiveness of physical therapy, spinal manipulative therapy, and exercise protocols. It also discusses emerging technologies and advancements in sEMG techniques that aim to enhance the accuracy and reliability of paraspinal muscle assessment. In summary, the application of sEMG in paraspinal muscles provides valuable insights into muscle function, dysfunction, and therapeutic interventions. By examining the literature on sEMG in paraspinal muscles, this review offers a comprehensive understanding of the current state of research, identifies knowledge gaps, and suggests future directions for optimizing the use of sEMG in assessing paraspinal muscle activity.

Effects of Strengthening Exercises on Human Kinetic Chains Based on a Systematic Review

Kinetic chains (KCs) are primarily affected by the load of different activities that recruit muscles from different regions. We explored the effects of strengthening exercises on KCs through muscle activation. Four databases were searched from 1990 to 2019. The muscles of each KC, their surface electromyography (sEMG), and the exercises conducted were reported. We found 36 studies that presented muscle activation using the percent (%) maximal voluntary isometric contraction (MVIC) or average sEMG for nine KCs in different regions. The % MVIC is presented as the following four categories: low (≤20%), moderate (21~40%), high (41~60%), and very high (>60%). Only four studies mentioned muscle activation in more than three KCs, while the remaining studies reported inconsistent sEMG processing, lacked normalization, and muscle activation in one or two KCs. The roles of stabilizers and the base of support in overhead throwing mobility using balance exercises were examined, and the concentric phase of chin-up and lat pull-down activated the entire KC by recruiting multiple muscles. Also, deep-water running was shown to prevent the risk of falls and enhance balance and stability. In addition, low-load trunk rotations improved the muscles of the back and external oblique activation. Based on this study's findings, closed-chain exercises activate more groups of muscles in a kinetic chain than open-chain exercises. However, no closed or open chain exercise can activate optimal KCs.

The effectiveness of different aerobic exercises to improve pain intensity and disability in chronic low back pain patients: a systematic review

Background: Physical activity, including aerobic exercise, is highly recommended for chronic low back pain (CLBP) patients to improve pain intensity and functional disability. Objectives: To assess the effectiveness of different aerobic exercises to reduce pain intensity and functional disability in patients with CLBP. Methods: A computer-aided search was performed to find Randomised Controlled Trials (RCTs) that evaluated the effectiveness of different aerobic exercises in CLBP. Articles published between January 2007 to December 2020 were included in the review. Quality assessment using the PEDro scale, extraction of relevant information, and evaluation of outcomes were done by two reviewers independently. Results: A total of 17 studies were included that involved 1146 participants. Outcomes suggested that aerobic exercise combined with other interventions was more effective than aerobic exercise alone. Aerobic exercise with higher frequency (≥ 5 days/week) and longer duration (≥ 12 weeks) were effective to gain clinically significant (≥ 30%) improvements. Environment and using pedometer did not seem to influence the outcomes. Conclusions: Pain intensity and functional disability in CLBP patients can be minimized by prescribing aerobic exercise. However, to get better improvements, aerobic exercise should be done in combination with other interventions and at optimum frequency and duration. Further studies should emphasize examining the optimal doses and duration of different aerobic exercises.

Effect of Load Distribution on Trunk Muscle Activity with Lunge Exercises in Amateur Athletes: Cross-Sectional Study

BACKGROUND

The effect of load distribution applied to the trunk musculature with lunge exercises has yet to be determined. The aim of this study was to evaluate the effect of load placement using dumbbells on the activation of the latissimus dorsi, erector spinae, external oblique, and rectus abdominis muscles during the lunge.

METHODS

Forty-two amateur athletes (21 men and 21 women) were recruited. Three lunge exercises were performed with different loading arrangements (ipsilateral, contralateral, and bilateral). The principal variable recorded for muscle activity was mean "root mean square" expressed as the percentage of the maximal voluntary isometric contraction.

RESULTS

There are statistically significant differences in the erector spinae (p < 0.001; p < 0.003) and external oblique muscles (p < 0.009; p < 0.001) compared with the contralateral side. The muscle on the opposite side of the load achieved higher activation for these muscles. The erector spinae and latissimus dorsi muscle did not reach a statistically significant difference with the contralateral side in any exercise (p > 0.05). The higher activation of the latissimus dorsi occurred on the same side on which the load was placed.

CONCLUSIONS

There was higher activation of the erector spinae, external oblique, and rectus abdominis muscles contralateral to the side of load placement during lunge exercise by amateur athletes.

A Comparative Electromyographic Analysis of Flying Squirrel and 3-Point Quadripod Exercise for Lumbar Multifidus Muscle Activations among Healthy Female Subjects

Physical therapists employ several exercises to alleviate low back pain (LBP). Electromyography (EMG) examination of exercises can monitor muscle activation to help clinicians determine the exercise’s effect on stabilisation, endurance, or strength. This study evaluated surface EMG activity comparison for Flying Squirrel Exercise (FSE) and the novel 3-Point Quadripod Exercise (3-PQE) to find the most effective exercise for stimulating the lumbar multifidus (LM) muscle. The study recruited 64 healthy young females (19–24 years). Raw data were normalized and are expressed as the percentage of maximum voluntary isometric contraction (%MVIC). The test–retest reliability of the EMG recordings was estimated using intraclass correlation coefficient (ICC3,1). One-way ANOVA was used to statistically analyse and compare the EMG amplitudes during the two exercises. The ICCs for 3-PQE and FSE were 0.94 (SEM, 21.7% MVIC) and 0.87 (SEM, 19.05% MVIC), respectively. The 3-PQE (69 ± 26% MVIC) demonstrated significantly higher activity than did FSE (30 ± 18% MVIC) (F = 15.573, p = 0.001). Thus, 3-PQE might be a feasible strategy for the prevention and rehabilitation of LBP in females.

Physiotherapeutic assessment and management of overactive bladder syndrome: a case report

INTRODUCTION

Overactive Bladder Syndrome (OAB) has multiple treatment methods including pharmacotherapy, pelvic floor muscle training, electrostimulation, or surgery. One of the nonpharmacological treatment options is physiotherapy including pelvic floor muscle training.

CASE DESCRIPTION

The patient was a 25 year-old woman who attended the urogynecological physiotherapy consulting room due to frequent sensations of bladder pressure. Manual inspection and ultrasound imaging was used by the physiotherapist in order to assess the function of pelvic and abominal structures. The patient reported pain symptoms during examination of several pelvic floor and abdominal muscles. The patient was judged eligible for urogynecological physiotherapeutic treatment. Manual therapy of the lumbopelvic hip complex, manual therapy per vaginum, manual therapy of the musculus piriformis, and therapy of the superficial back line myofascial meridian and the lateral line myofascial meridian were used. During the final session, the patient reported an improvement in relation to the symptoms presented, most notably no frequent feeling of bladder pressure.

CONCLUSIONS

Treatment of OAB is often a multistage process involving application of different therapies by a multidisciplinary team. For this patient, physiotherapy assessment and intervention were an integral part of the conservative management of OAB.

Effects of diaphragmatic and iliopsoas myofascial release in patients with chronic low back pain: A randomized controlled study

BACKGROUND

Myofascial release (MFR) technique is frequently used in musculoskeletal problems. There are many studies of the MFR technique on the diaphragm or iliopsoas muscle. However, no studies in the literature performed both diaphragmatic and iliopsoas MFR techniques in patients with chronic low back pain.

OBJECTIVE

To investigate the effects of diaphragmatic and iliopsoas MFR techniques on pain, lumbar spine range of motion (ROM), chest wall mobility, and flexibility in patients with chronic low back pain.

DESIGN

Randomized controlled clinical study.

PARTICIPANTS

Forty-two participants with chronic low back pain, aged between 20 and 50 years.

INTERVENTION

The sample was randomly allocated into one of two groups; the myofascial group (n = 21) and control group (n = 21) received the MFR technique or the placebo MFR technique as a complementary therapy to traditional physiotherapy treatment.

OUTCOME MEASURES

Primary outcomes were pain, chest wall mobility, lumbar spine range of motion (ROM), and flexibility. Secondary outcomes were depression, kinesiophobia, and functional disability.

RESULTS

The MFR techniques significantly reduced the pain, with a between-group difference of -2.05 (95% CI, -2.93 to -1.15) for rest, -2.62 (95% CI, -3.34 to -1.89) for trunk flexion, and -2.00 (95% CI, -2.84 to -1.16) for trunk extension in favor of the EG. MFR techniques significantly increased the lumbar spine ROM after interventions, with a between-group difference of 16.67° (95% CI, 8.87 to 24.47) for flexion, 7.63° (95% CI, 5.44 to 9.80) for extension and, 9.53° (95% CI, 6.57 to 12.48) for right lateral flexion. There was also a significant difference between the groups in flexibility in favor of the MG of 1.95 cm (95% CI, 1.41 to 2.49) for MST, -13.52 cm (95% CI, -20.18 to -6.86) for trunk flexion and, -4.37 cm (-6.50 to -2.28) for right lateral flexion The MFR techniques also significantly increased the chest wall mobility after interventions, with a between-group difference of 2.52 cm (95% CI, 1.82 to 3.23) for the xiphoid region and 3.48 cm (95% CI, 2.60 to 4.36) for the subcostal region.

CONCLUSION

Diaphragmatic and iliopsoas MFR techniques may be effective in pain, lumbar spine ROM, flexibility, and chest wall mobility in patients with chronic low back pain.

CLINICAL TRIALS IDENTIFIER

NCT04415021.

The facilitation of trunk muscles by abdominal bracing during walking in chronic low back pain patients

Walking is known to be beneficial for chronic low back pain (LBP) patients and fast walking recruits more trunk muscles. Abdominal bracing has also been shown to improve LBP and facilitate several trunk muscles. We aimed to investigate the effects of walking velocity and abdominal bracing on the activation of trunk muscles in chronic LBP patients during walking. Forty-six volunteers with chronic LBP underwent walking exercise on the treadmill without ("non-braced walking") and with abdominal bracing ("braced walking") at speeds of 4, 5, and 6 km/h, with the surface electrodes placed on their trunk muscles to measure muscle activity. The root mean square values of the surface electromyography amplitude data were obtained at the multifidus of lower (ML) and upper lumbar (MU), erector spinae of lower lumbar (EL) and thoracic (ET), rectus abdominis (RA), and external oblique (EO). All muscles activated significantly more at faster walking. The "braced walking" facilitated the ET and RA significantly more than the "non-braced walking". The interaction between the walking speed and abdominal bracing was significant at ML, MU, and RA. The increase in muscle activation observed at lower speed diminished as speed increased. Since "braced walking" seems to additionally facilitate the trunk muscles especially at slower gait speeds, patients who cannot walk fast may still be able to train their muscles by "braced walking."

Effect of direct vibration on the activity of deep trunk muscles of patients with non-specific chronic low back pain

BACKGROUND

Vibration training is an adjuvant to muscle-strengthening exercises.

OBJECTIVE

To investigate the short-term effects of direct vibration on the deep trunk muscles of patients with non-specific chronic low back pain (CLBP).

METHODS

Participants with non-specific CLBP were randomly placed into two groups: the vibration-plus stabilization exercise (VSE) group (n= 31) and the conventional stabilization exercise (CSE) group (n= 31). The groups underwent 12 sessions of an exercise program. The thickness and activity of the trunk muscles were measured using ultrasonography and surface electromyography.

RESULTS

Ultrasonography revealed that the ratio of muscle thickness to contraction and relaxation was statistically increased after exercise in the bilateral transversus abdominis (TrA) and lumbar multifidus (LM) muscles in the CSE group (p= 0.031), and in the bilateral TrA, LM, and internal oblique (IO) muscles in the VSE group (p< 0.001). The LM/lumbar erector spinae (LES) ratio in the CSE group (p= 0.037), and the IO/rectus abdominis (RA), TrA/RA, and LM/LES ratios in the VSE group (p= 0.019) were statistically increased. Multiple regression analysis showed that symptom improvement was related to increased activity of the deep trunk muscles in the VSE group (p< 0.001).

CONCLUSION

Direct vibration can increase the selective activity of contracting deep trunk muscles.

Study on the Effects of Different Seat and Leg Support Conditions of a Trunk Rehabilitation Robot

Performance of trunk rehabilitation exercises while sitting on movable surfaces with feet on the ground can increase trunk and leg muscle activations, and constraining the feet to move with the seat isolates control of the trunk. However, there are no detailed studies on the effects of these different leg supports on the trunk and leg muscle activations under unstable and forcefully perturbed seating conditions. We have recently devised a trunk rehabilitation robot that can generate unstable and forcefully perturbed sitting surfaces, and can be used with ground-mounted or seat-connected footrests. In this study, we have evaluated the differences in balance performance, trunk movement and muscle activation (trunk and legs) of fourteen healthy adults caused by the use of these different footrest configurations under the different seating scenarios. The center of pressure and trunk movement results show that the seat-connected footrest may be a more suitable choice for use in a balance recovery focused rehabilitation protocol, while the ground-mounted footrest may be a more suitable choice for a trunk movement focused rehabilitation protocol. Although it is difficult to make a clear selection between footrests due to the mixed trends observed in the muscle activation results, it appears that the seat-connected footrest may be preferable for use with the unstable seat as it causes greater muscle activations. Furthermore, the results provide limited evidence that targeting of a particular muscle group may be possible through careful selection of the seat and footrest conditions. Therefore, it may be possible to utilize the trunk rehabilitation robot to maximize the training outcomes for a wide range of patients through careful selection of training protocols.

Analysis of muscle activation in children and adolescents with severe cerebral palsy

Abstract Introduction: Children and adolescents with spastic quadriparesis have a worse selective motor control, and studies with this population are still very scarce. The same is true with scientific evidence of one of the methods most used as a physiotherapeutic treatment in this population, the Bobath Concept. Objective: To evaluate spine erector muscles activation, gluteus medius and gluteus maximus, through the handling of the Bobath Concept and the sustained kneeling posture in subjects with a diagnosis of severe cerebral palsy; and to compare muscle activation with a reference group, in order to increase the reliability of this study. Methods: A cross-sectional study was carried out with 38 children and adolescents with cerebral palsy, classified by GMFCS at levels IV and V, and 20 healthy participants, aged between 3 and 18 years. They were submitted to the handling of the Bobath Concept and to the sustained kneeling posture, with muscle activation obtained by electromyography. Results: We observed significant muscle activation during handling in side-sitting, with weight transfer and without the help of another therapist, and in the sustained kneeling posture, for the erector of the spine and gluteus medius. Conclusion: The evidence from this study suggests that both the handling in side-sitting and the sustained kneeling posture cause significant muscle activation in the erector of the spine and gluteus medius for severe quadriparesis subjects, GMFCS IV and V, which can contribute to the improvement of postural control and decision-making in physical therapy practice.

Electromyographic Analysis of Hip and Trunk Muscle Activity During Side Bridge Exercises in Subjects With Gluteus Medius Weakness

CONTEXT

Side bridge exercises strengthen the hip, trunk, and abdominal muscles and challenge the trunk muscles without the high lumbar compression associated with trunk extension or curls. Previous research using electromyography (EMG) reports that performance of the side bridge exercise highly activates the gluteus medius (Gmed). However, to the best of our knowledge, no previous research has investigated EMG amplitude in the hip and trunk muscles during side bridge exercise in subjects with Gmed weakness.

OBJECTIVE

The purpose of this study was to examine the EMG activity of the hip and trunk muscles during 3 variations of the side bridge exercise (side bridge, side bridge with knee flexion, and side bridge with knee flexion and hip abduction of the top leg) in subjects with Gmed weakness.

DESIGN

Repeated-measures experimental design.

SETTING

Research laboratory.

PATIENTS

Thirty subjects (15 females and 15 males) with Gmed weakness participated in this study.

INTERVENTION

Each subject performed 3 variations of the side bridge exercise in random order.

MAIN OUTCOME MEASURES

Surface EMG was used to measure the muscle activities of the rectus abdominis, external oblique, longissimus thoracis, multifidus, Gmed, gluteus maximus, and tensor fasciae latae (TFL), and Gmed/TFL muscle activity ratio during 3 variations of the side bridge exercise.

RESULTS

There were significant differences in Gmed (F2,56 = 110.054, P < .001), gluteus maximus (F2,56 = 36.416, P < .001), and TFL (F2,56 = 108.342, P < .001) muscles among the 3 side bridge exercises. There were significant differences in the Gmed/TFL muscle ratio (F2,56 = 20.738, P < .001).

CONCLUSION

Among 3 side bridge exercises, the side bridge with knee flexion may be effective for the individuals with Gmed weakness among 3 side bridge exercises to strengthen the gluteal muscles, considering the difficulty of the exercise and relative contribution of Gmed and TFL.

Effects of core stability training program on trunk muscle endurance in deaf children: A preliminary study

INTRODUCTION

Sport participation is an important for deaf children as participants experience physical, psychological and social benefits; however, the beneficial effect of core stability training on core muscle endurance is unclear. The present study aimed to examine the effects of an 8-week core stability exercise training program on endurance of trunk muscles in deaf children.

METHODS

Twenty male deaf students (age, 16.5 ± 0.65 y; body mass, 62.08 ± 5.39 kg; BMI, 22.33 ± 2.24 kg/m²) volunteered to participate in this study and were randomly assigned to experimental (EXP, n = 10) and control (CON, n = 10) groups. The subjects in the EXP group performed 3 times a week for 8 weeks period of core stability training program and tested trunk muscle endurance including prone bridge, supine bridge and flexor endurance tests at pre and post 8 weeks intervention.

RESULTS

The CON group did not show any significant change after training period (p > 0.05). The EXP group showed significantly changes in core stability muscle endurance tests following the 8-week core stability training program (p < 0.05). In addition, the EXP group indicated statistically significant changes than the CON group in truck muscle endurance (p < 0.05).

CONCLUSIONS

The results indicated that core stability training program improved trunk muscle endurance. Therefore, this training approach can be recommended in deaf rehabilitation programs to improve trunk muscle endurance.

Muscle Activation in the Shoulder Girdle and Lumbopelvic-Hip Complex During Common Therapeutic Exercises

CONTEXT

Lumbopelvic-hip complex (LPHC) exercises are used to increase stabilization within the human body. Torso-elevated side support (TESS), foot-elevated side support (FESS), prone bridge plank (PBP), and V-sit are common LPHC exercises.

OBJECTIVE

To evaluate muscle activation in the shoulder girdle and LPHC during 4 LPHC exercises and evaluate the reasoning for termination.

STUDY DESIGN

Cross-sectional study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

Seventeen healthy participants (12 males and 5 females; age: 21.47 [3.16] y, height: 179.73 [8.92] cm, mass: 76.89 [11.17] kg).

MAIN OUTCOME MEASURES

Participants completed 2 repetitions of the TESS, FESS, PBP, and V-sit until failure. Surface electromyography of the middle deltoid, latissimus dorsi, middle trapezius, rectus abdominis, erector spinae, external oblique, and gluteus medius were recorded and normalized to maximum voluntary isometric contraction (MVIC). The duration of exercise and subjective reasoning for termination of exercise was completed following the 4 tasks.

RESULTS

The TESS and PBP had significantly greater middle deltoid muscle activation (TESS: 55.66% [24.45%] MVIC and PBP: 42.63% [18.25%] MVIC) compared with the FESS (10.10% [10.04%] MVIC) and V-sit (2.21% [1.94%] MVIC), P < .05. The TESS produced significantly greater external oblique activity (78.13% [32.32%] MVIC) than the PBP (54.99% [19.54%] MVIC), P < .05. Due to shoulder fatigue and pain, 41.1% and 17.0% of participants terminated the TESS, respectively. The PBP was terminated due to abdominal fatigue (41.1%) and upper-extremity fatigue (47.0%).

CONCLUSIONS

The V-sit resulted in isolated activity of the abdominal portion of the LPHC. The FESS had increased global co-contraction of the LPHC compared with the TESS. The PBP and TESS had significant muscle activation in the upper-extremity.

Effect of an inverted seated position with upper arm blood flow restriction on measures of elbow flexors neuromuscular performance

Purpose

The objective of the investigation was to determine the concomitant effects of upper arm blood flow restriction (BFR) and inversion on elbow flexors neuromuscular responses.

Methods

Randomly allocated, 13 volunteers performed four conditions in a within-subject design: rest (control, 1-min upright position without BFR), control (1-min upright with BFR), 1-min inverted (without BFR), and 1-min inverted with BFR. Evoked and voluntary contractile properties, before, during and after a 30-s maximum voluntary contraction (MVC) exercise intervention were examined as well as pain scale.

Results

Inversion induced significant pre-exercise intervention decreases in elbow flexors MVC (21.1%, ηp2 = 0.48, p = 0.02) and resting evoked twitch forces (29.4%, ηp2 = 0.34, p = 0.03). The 30-s MVC induced significantly greater pre- to post-test decreases in potentiated twitch force (ηp2 = 0.61, p = 0.0009) during inversion (↓75%) than upright (↓65.3%) conditions. Overall, BFR decreased MVC force 4.8% (ηp2 = 0.37, p = 0.05). For upright position, BFR induced 21.0% reductions in M-wave amplitude (ηp2 = 0.44, p = 0.04). There were no significant differences for electromyographic activity or voluntary activation as measured with the interpolated twitch technique. For all conditions, there was a significant increase in pain scale between the 40–60 s intervals and post-30-s MVC (upright<inversion, and without BFR<BFR).

Conclusion

The concomitant application of inversion with elbow flexors BFR only amplified neuromuscular performance impairments to a small degree. Individuals who execute forceful contractions when inverted or with BFR should be cognizant that force output may be impaired.

Relationship of Barbell and Dumbbell Repetitions With One Repetition Maximum Bench Press in College Football Players

ABSTRACT

Heinecke, ML, Mauldin, ML, Hunter, ML, Mann, JB, and Mayhew, JL. Relationship of barbell and dumbbell repetitions with one repetition maximum bench press in college football players. J Strength Cond Res 35(2S): S66-S71, 2021-Dumbbell training to augment barbell training is gaining popularity. However, information is lacking that details the compatibility of strength and endurance between dumbbell and barbell performances in the same exercise. Therefore, the purposes of this study were to compare the similarity of muscular endurance performance between dumbbell and barbell exercises and to assess the accuracy of predicting one repetition maximum (1RM) barbell bench press from barbell and dumbbell repetitions to fatigue (RTF). College football players (n = 40) performed 1RM barbell bench press and RTF with a 90.9-kg barbell. On separate days, unilateral (45.5 kg) and bilateral dumbbell (90.9 kg) RTF were performed. Barbell RTF (13.8 ± 9.2) were significantly greater (effect size [ES] = 0.14) than bilateral dumbbell RTF (12.5 ± 9.5) but highly correlated (r = 0.96). Unilateral dumbbell RTF were significantly greater (ES = 0.13) for dominant hand (10.8 ± 10.1) than nondominant hand (9.5 ± 9.7) but highly correlated (r = 0.97). Prediction of 1RM barbell bench press was equally effective using a constant weight barbell (r = 0.90) or equivalent weight bilateral dumbbells (r = 0.87) with total errors of 7.3 and 8.2%, respectively. Barbell and dumbbell repetitions with equivalent weights place a similar demand on the upper-body musculature for training and testing purposes in football athletes.

Evaluating objective measures of impairment to trunk strength and control for cross-country sit skiing

In Paralympic cross-country sit skiing, athlete classification is performed by an expert panel, so it may be affected by subjectivity. An evidence-based classification is required, in which objective measures of impairment must be identified. The purposes of this study were: (i) to evaluate the reliability of 5 trunk strength measures and 18 trunk control measures developed for the purposes of classification; (ii) to rank the objective measures, according to the largest effects on performance. Using a new testing device, 14 elite sit-skiers performed two upright seated press tests and one simulated poling test to evaluate trunk strength. They were also subjected to unpredictable balance perturbations to measure trunk control. Tests were repeated on two separate days and test–retest reliability of trunk strength and trunk control measures was evaluated. A cluster analysis was run and correlation was evaluated, including all strength and control measures, to identify the measures that contributed most to clustering participants. Intraclass correlations coefficients (ICC) were 0.71 < ICC < 0.98 and 0.83 < ICC < 0.99 for upright seated press and perturbations, respectively. Cluster analysis identified three clusters with relevance for strength and balance control measures. For strength, in upright seated press peak anterior pushing force without backrest (effect size = 0.77) and ratio of peak anterior pushing force without and with backrest (effect size = 0.72) were significant. For balance control measures, trunk range of motion in forward (effect size = 0.81) and backward (effect size = 0.75) perturbations also contributed. High correlations (− 0.76 < r < − 0.53) were found between strength and control measures. The new testing device, protocol, and the cluster analysis show promising results in assessing impairment of trunk strength and control to empower an evidence-based classification.

Lumbar Intervertebral Disc Degeneration Does Not Affect Muscle Synergy for Rowing Activities

Rowers with disc degeneration may have motor control dysfunction during rowing. This study is aimed at clarifying the trunk and lower extremity muscle synergy during rowing and at comparing the muscle synergy between elite rowers with and without lumbar intervertebral disc degeneration. Twelve elite collegiate rowers (with disc degeneration, n = 6; without disc degeneration, n = 6) were included in this study. Midline sagittal images obtained by lumbar T2-weighted magnetic resonance imaging were used to evaluate disc degeneration. Participants with one or more degenerated discs were classified into the disc degeneration group. A 2000 m race trial using a rowing ergometer was conducted. Surface electrodes were attached to the right rectus abdominis, external oblique, internal oblique, latissimus dorsi, multifidus, erector spinae, rectus femoris, and biceps femoris. The activity of the muscles was measured during one stroke immediately after 20% and 80% of the rowing trial. Nonnegative matrix factorization was used to extract the muscle synergies from the electromyographic data. To compare the muscle synergies, a scalar product (SP) evaluating synergy coincidence was calculated, and the muscle synergies were considered identical at SP > 75%. Both groups had only one module in the 20% and 80% time points of the trial. At the 20% time point of the 2000 m rowing trial, the SP of the module was 99.8%. At the 80% time point, the SP of the module was 99.9%. The SP results indicate that, at 20% and 80% time points, both groups had the same module. The module showed a high contribution in all muscles. The activation coefficients indicated that the module was always highly activated throughout the rowing stroke in both groups. The trunk and lower extremity muscles are mobilized through the rowing stroke and maintain coordination during rowing. There was no difference in the muscle synergy between the rowers with and without lumbar intervertebral disc degeneration.

Effects of lumbar segmental stabilization exercise and respiratory exercise on the vital capacity in patients with chronic back pain

BACKGROUND

Trunk stabilization contributes to the efficient control of body movements in daily life, and it plays an important role in maintaining the proper alignment of the body and preventing low back pain.

OBJECTIVE

This study aimed to identify the effectiveness of breathing exercises and lumbar segmental exercises on the vital capacity of lumbar instability patients.

METHOD

Fifty-nine patients suffering from chronic low back pain participated in this study. They were randomly divided into three groups: experiment group 1 performed breathing and segmental stabilization exercises (n= 20), experiment group 2 performed segmental stabilization exercises (n= 20), and the control group performed the modality treatment (n= 19). The measurements were assessed on vital capacity.

RESULTS

The difference in the forced vital capacity, maximal expiratory pressure, and maximal inspiratory pressure at pre- and post-intervention was significant in the RE+LSSE and LSSE groups (p< 0.05) and among all groups (p< 0.05). The difference in the forced expiratory volume at one second of each group was significant (p< 0.05) but was not significant among groups (p> 0.05).

CONCLUSION

In conclusion, the lumbar segmental stabilization exercise activates the deep muscle and improves the respiratory function and respiratory pressure, when used for chronic low back pain patients with segmental instability.

Effects of upper-extremity movements on electromyographic activities of selected trunk muscles during leaning forward

BACKGROUND

Leaning forward has been accepted as a foundational approach to facilitate trunk-stabilizing muscles in the abdominal and lumbopelvic regions for patients with back pain during rehabilitation. However, how trunk muscles are activated and recruited during leaning forward performed under dynamic upper-extremity motion conditions is not completely understood.

OBJECTIVE

To determine whether activation of selected trunk muscles changes depending on shoulder movements during leaning forward exercise in healthy young adults.

METHODS

Twenty-four healthy adults (6 men and 18 women) participated in this study. The participants performed 3 types of leaning forward exercises: leaning forward alone (leaning forward 1), leaning forward with horizontal shoulder abduction (leaning forward 2), and leaning forward with shoulder flexion (leaning forward 3). Surface electromyography (EMG) was used to record activation of the erector spinae (ES), multifidus (MF), rectus abdominis (RA), and internal oblique (IO) on the dominant side.

RESULTS

There was a significant main effect of exercise type on the activation of the IO, RA, and MF muscles. Activation of the IO and MF during leaning forward 1 was significantly decreased compared to activation in leaning forward 2 and 3; the activation of IO and RA showed the greatest increase during leaning forward 3. Furthermore, the IO/RA ratio was significantly increased during leaning forward 2 and 3 in comparison to leaning forward 1; the MF/ES ratio was also significantly increased during leaning forward 3, compared with leaning forward 1.

CONCLUSION

The integration of shoulder movements during leaning forward exercises could be effective in the facilitation of EMG activity of IO and MF muscles, especially with shoulder flexion.

The Effect of Traditional and Stabilization-Oriented Exercises on Deep Stabilization System Function in Elite Futsal Players

Background: This study aimed to compare the effect of traditional and stability-oriented strength exercises on trunk stability and deep stabilization system (DSS) activation in elite futsal players. Methods: Twenty elite futsal players (21–34 years, 180 ± 13 cm, 79 ± 15 kg) were randomly divided into a group that performed stability-oriented exercises and a group that performed traditional strength exercises. Both interventions lasted for 10 weeks and included 25 strength training sessions. Main outcome measures: The DSS pretest and posttest included the diaphragm test, trunk flexion test, back extension test, hip flexion test, intraabdominal pressure test, and a side plank test on a 1–5 point scale. Results: Both groups had similar initial test results, where the stability-oriented exercise group had significantly improved intraabdominal pressure test (p = 0.004, by lower quartile rate), trunk flexion (p = 0.036, by 0.5 grade in median), and side plank (p = 0.002, by 1 grade in median) in posttest results. Traditional exercise did not change the results of any of the included DSS function tests. Conclusions: Stabilization-oriented exercises effectively activate the functions of the DSS and should be prioritized over traditional strength exercises in injury prevention training programs. The use of stabilization-oriented exercises might prevent injury and overloading in elite futsal players.

Regional differences between superficial and deep lumbar multifidus in patients with chronic lumbar spine pathology

BACKGROUND

Due to its unique arrangement, the deep and superficial fibers of the multifidus may have differential roles for maintaining spine stabilization and lumbar posture; the superficial multifidus is responsible for lumbar extension and the deep multifidus for intersegmental stability. In patients with chronic lumbar spine pathology, muscle activation patterns have been shown to be attenuated or delayed in the deep, but not superficial, multifidus. This has been interpreted as pain differentially influencing the deep region. However, it is unclear if degenerative changes affecting the composition and function of the multifidus differs between the superficial and deep regions, an alternative explanation for these electrophysiological changes. Therefore, the goal of this study was to investigate macrostructural and microstructural differences between the superficial and deep regions of the multifidus muscle in patients with lumbar spine pathology.

METHODS

In 16 patients undergoing lumbar spinal surgery for degenerative conditions, multifidus biopsies were acquired at two distinct locations: 1) the most superficial portion of muscle adjacent to the spinous process and 2) approximately 1 cm lateral to the spinous process and deeper at the spinolaminar border of the affected vertebral level. Structural features related to muscle function were histologically compared between these superficial and deep regions, including tissue composition, fat fraction, fiber cross sectional area, fiber type, regeneration, degeneration, vascularity and inflammation.

RESULTS

No significant differences in fat signal fraction, muscle area, fiber cross sectional area, muscle regeneration, muscle degeneration, or vascularization were found between the superficial and deep regions of the multifidus. Total collagen content between the two regions was the same. However, the superficial region of the multifidus was found to have less loose and more dense collagen than the deep region.

CONCLUSIONS

The results of our study did not support that the deep region of the multifidus is more degenerated in patients with lumbar spine pathology, as gross degenerative changes in muscle microstructure and macrostructure were the same in the superficial and deep regions of the multifidus. In these patients, the multifidus is not protected in order to maintain mobility and structural stability of the spine.

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.

Abdominal muscle activation: An EMG study of the Sahrmann five-level core stability test

Background

Sahrmann five-level core stability test protocol has been used to evaluate the ability of the core muscles to stabilize the spine. However, validation studies on the Sahrmann protocol are limited.

Objective

The purpose of this study was to compare the different levels of Sahrmann five-level core stability (levels 1-5) on the muscle activity of rectus abdominis (RA), external oblique (EO), and transverse abdominis/internal oblique (TrA/IO).

Methods

Twenty-two asymptomatic male participants aged 21.3 6 ± 1 .59 years were recruited. Participants were instructed to perform maximum voluntary contraction (MVC) and five levels of Sahrmann five-level core stability test guided with a pressure biofeedback unit (PBU). The surface electromyography (EMG) data of each muscle during five levels of Sahrmann five-level core stability test were normalized as a percentage of MVC.

Results

Results showed significant differences in the normalized EMGs of RA [ χ 2 (4) = 64.80, p < 0 .001], EO [ χ 2 (4) = 58.11, p < 0 .001], and TrA/IO [ χ 2 (4) = 56.00, p < 0 .001] between the five levels of Sahrmann five-level core stability test. Post-hoc analysis revealed Sahrmann levels 5 and 3 have significantly higher abdominal EMG signals than levels 4, 2, and 1 ( p < 0 .001).

Conclusion

In conclusion, the Sahrmann five-level core stability test differs according to the level of Sahrmann tests. Significantly higher abdominal muscle activities were observed during levels 3 and 5. Therefore, the classification exchange in levels 3 and 4 of the Sahrmann five-level core stability test should be reconsidered in the future.

The Vojta approach changes thicknesses of abdominal muscles and gait in children with spastic cerebral palsy: A randomized controlled trial, pilot study

BACKGROUND

Children with cerebral palsy (CP) have abnormal postures and gait patterns. Many physiotherapists use the Vojta approach as intervention for children with CP. However, its effects remain unclear.

OBJECTIVE

This study aimed to investigate the effect of the Vojta approach on abdominal muscles and gait in children with spastic CP.

METHODS

Thirteen children with spastic CP were randomly assigned to a general exercise and a Vojta approach group. The interventions were administered in 30 min sessions, 3 times a week for a total of 6 weeks. We used ultrasonography to measure the thicknesses of the abdominal muscles. The gait and foot pressure were measured by GAITRite.

RESULTS

The Vojta approach group showed significant difference in the thicknesses of the rectus abdominis, and external oblique abdominal muscles, which are involved in trunk stability (p< 0.05). There were significant differences in the step width, functional ambulation profile, swing time, stance time, and single support % of cycle as well as foot pressure distribution (p< 0.05).

CONCLUSION

The Vojta approach may be considered as an effective treatment method for improving trunk stability and gait functions of children with spastic CP.

The effect of lumbar stabilization and walking exercises on chronic low back pain: A randomized controlled trial

BACKGROUND

Various exercises have been proposed to mitigate chronic low back pain (LBP). However, to date, no one particular exercise has been shown to be superior. Hence, the aim of this study was to compare the efficiency between 2 exercises: the individualized graded lumbar stabilization exercise (IGLSE) and walking exercise (WE).

METHODS

A randomized controlled trial was conducted in 48 participants with chronic LBP. After screening, participants were randomized to 1 of 4 groups: flexibility exercise, WE, stabilization exercise (SE), and stabilization with WE (SWE) groups. Participants underwent each exercise for 6 weeks. The primary outcome was visual analog scale (VAS) of LBP during rest and physical activity. Secondary outcomes were as follows: VAS of radiating pain measured during rest and physical activity; frequency of medication use (number of times/day); Oswestry disability index; Beck depression inventory; endurances of specific posture; and strength of lumbar extensor muscles.

RESULTS

LBP during physical activity was significantly decreased in all 4 groups. Exercise frequency was significantly increased in the SE and WE groups; exercise time was significantly increased in the SE group. The endurance of supine, side lying, and prone posture were significantly improved in the WE and SWE groups.

CONCLUSIONS

Lumbar SE and WE can be recommended for patients with chronic LBP because they not only relieve back pain but also prevent chronic back pain through improving muscle endurance.

Revisiting the effect of manipulating lumbar stability with load magnitudes and positions: The effect of sex on trunk muscle activation

BACKGROUND

Lumbar spine stability is regularly studied by positioning different loads at different heights and distance and measuring trunk muscle activation changes. Some of these studies have reported sex differences, but this needs to be revisited while controlling for confounding factors.

METHOD

20 males and 20 females sustained three static standing postures, with various loads (0, 5 and 10% of body weight), to evaluate the effect of height and distance. Activation of 12 trunk muscles was recorded with surface electromyography (EMG).

RESULTS

Females activated their external obliques a little more than males, with increases ranging between 1.5 and 2.3% of maximal voluntary activation (MVA), which corresponds to strong effect sizes (Cohen's d ranging between 0.86 and 1.13). However, the significant Sex × Height, Sex × Distance and Sex × Load interactions observed for different trunk muscles led to small differential effects (≤1% MVA). Increasing load height slightly increased and decreased back and abdominal muscle activation, respectively, generally by less than 1% MVA.

CONCLUSION

The higher activation of the external obliques observed in females might be of clinical value, relative to the required overall trunk muscle activation (5%), to preserve lumbar stability. Other effects were negligible.

Does a core stabilization exercise program have a role on shoulder rehabilitation? A comparative study in young females

OBJECTIVES

This study aims to evaluate the effect of core stabilization exercises and to explore the immediate effect of core muscles-activated posture on shoulder maximal voluntary isometric contraction (MVIC) strength.

PATIENTS AND METHODS

Between November 2016 and January 2015, a total of 75 healthy female volunteers (mean age 25.36 years; range, 18 to 30 years) were included. Of these, 42 consecutive volunteers were assigned as the study group, while the remaining 33 volunteers were assigned as the control group. The study group completed a six-week core stabilization home-based exercise program. Two measurements were performed with six-week interval. A set of three repetitions for each shoulder side was performed by an electronic dynamometer under two conditions: core muscles relaxed and activated. Measurements were monitored real-time with a connected computer and recorded in Newton.

RESULTS

The activation of core muscles during the measurement significantly decreased the MVIC values in both groups (p<0.05). The MVIC values significantly increased after home-based exercise program in both conditions (p<0.05).

CONCLUSION

Our study showed that six-week core stabilization exercise program had a significant positive effect on the shoulder MVIC strength. This result may support the use of core stabilization exercises in the early periods of shoulder rehabilitation when the shoulder muscle strengthening exercises are painful.

Water-filled training tubes increase core muscle activation and somatosensory control of balance during squat

This study examined trunk muscle activation, balance and proprioception while squatting with a water-filled training tube (WT) and a traditional barbell (BB), with either closed (CE) or open eyes (OE). Eighteen male elite Gaelic footballers performed an isometric squat under the following conditions: BB-OE, BB-CE, WT-OE and WT-CE. The activity of rectus abdominis (RA), external oblique (EO) and multifidus (MF) was measured using electromyography, along with sway of the centre of pressure (CoP) using a force platform. Only the EO and the MF muscles exhibited an increased activity with WT (p < 0.01). In the medio-lateral direction both the velocity and range of the CoP increased significantly with WT (p < 0.01). Interestingly, the range of the CoP for the WT-CE condition was significantly lower than WT-OE (p < 0.05, d = 0.44), whilst the velocity of the CoP was marginally reduced (d = 0.29). WT elicited a greater level core muscle activation and created a greater challenge to postural stability when compared to a BB. It appears that WT does not benefit from vision but emphasises the somatosensory control of balance. The use of WT may be beneficial in those sports requiring development of somatosensory/proprioceptive contribution to balance control.

Reliability of Electromyographic Assessment of Biceps Brachii and Triceps Brachii in Cricketers

Objective

The purpose of this study is to determine the intraexaminer and interexaminer reliability of electromyographic assessment of biceps brachii (BB) and triceps brachii (TB) muscles in cricketers.

Methods

Sixteen healthy male cricketers (ages 14-35 years) recruited from Jamia Millia Islamia, New Delhi, India were tested on 2 occasions that were held 1 week apart. On the first occasion, only examiner 1 performed the testing; on the second occasion, examiner 1, examiner 2, and examiner 3 all performed testing. While testing for surface electromyography (sEMG) activity of BB and TB muscles, participants were asked to produce maximal voluntary isometric contraction (MVIC), which was to be held for 5 seconds against the resistance provided by an examiner. Participants performed 3 MVICs per muscle per examiner, with a rest interval of 3 minutes between consecutive contractions. Intraclass correlation coefficient, standard error of measurement, and minimum detectable change were calculated to determine the reliability of repeated sEMG measurements.

Results

Nonsignificant differences were observed for the 2 trials completed by examiner 1 (paired t test) and testing done by all 3 examiners (repeated measures analysis of variance) at P < .05 for both BB and TB. Intraclass correlation coefficient values ranged from .84 to .86 for BB and .89 to .98 for TB. Standard error of measurement (minimum detectable change) was .052 (.144) mV and .041 (.114) mV for BB intraexaminer and interexaminer reliability testing, respectively, and .018 (.051) mV and .043 (.119) mV for TB intraexaminer and interexaminer reliability testing. Ninety-five percent of the mean differences between almost all of the repeated measurements were found to lie within the agreement intervals estimated by Bland-Altman plots.

Conclusion

This preliminary study suggests that sEMG is a reliable tool with excellent intraexaminer and interexaminer reliability for assessing the activity of BB and TB muscles in male cricketers. These findings suggest that sEMG can be used to assess MVIC activity of these muscles in clinical settings, as well as in research area.

The effect of the trunk and gluteus maximus muscle activities according to support surface and hip joint rotation during bridge exercise

[Purpose] The purposes of this study were to strengthen gluteus maximus and trunk muscles depending upon the hip joint direction by bridging exercise on an unstable and stable surface, and to suggest an intervention method for efficient and selective exercise. [Participants and Methods] The test measured the muscle activities with the external rotation and internal rotation of 25 degrees and hip joint neutral position of 0 degree on a stable and unstable surface each exercise 3 times for 9 seconds. [Results] External oblique abdominis showed a higher muscle activity on the unstable surface and internal rotation. Erector spinae showed no significant difference on the surfaces and demonstrated the highest muscle activity at the internal rotation. Gluteus maximus showed a higher muscle activity on the stable surface and external rotation and the interaction effect between the surface and the angle indicated a statistical significance as well. [Conclusion] Muscle activities appear different depending upon the change of surface and joint angle, and it can be said that the correct mobilization of muscle fiber relying on the muscle arrangement direction and muscle contraction direction is the most important factor for gluteus maximus.

Scapular muscle balance and spinal stabilizer recruitment during an inverted row

Persons with subacromial impingement syndrome (SIS) have an imbalance in scapular muscle recruitment. To avoid humeral head compression against the coracoacromial arch during the early stages of rehabilitation, physical therapists recommend movements targeting scapular retraction, shoulder depression, and arm extension such as the inverted row (IR) exercise. The purposes of this study were to describe: (1) scapular balance ratios during an IR and (2) the magnitudes of recruitment of spinal stabilizer muscles. Scapular muscle balance ratios from 26 healthy participants were calculated from electromyographic (EMG) activity of the upper trapezius (UTP), lower trapezius (LTP), middle trapezius (MTP), serratus anterior (SA), posterior deltoid (PD), latissimus dorsi (LD), and biceps brachii (BB) during an IR on stable and unstable support surfaces. Balance ratios were obtained by dividing normalized EMG activity of the UTP by the normalized EMG values from each of the other six muscles. Four median scapular balance ratios (UTP/MTP, UTP/PD, UTP/LD, and UTP/BB) ranged from 0.9 to 2.2, whereas the UTP/LTP ratio ranged from 1.6 to 2.2 and the UTP/SA ratio ranged from 1 to 4.7. Activation of seven muscles promoted safe containment of the humeral head within the glenoid fossa during the IR in healthy persons and potentially people with the tendency for development of SIS. Four spinal stabilizer muscles were examined: longissimus thoracis (LT), multifidus (MF), rectus abdominis (RA), and external oblique (EO). Spinal stabilizer EMG activation values ranged from 34% to 40% maximum voluntary isometric contraction (MVIC) for the RA and EO and from 54% to 66% MVIC for the LT and MF.

Relationship between scapular muscle and core endurance in healthy subjects

BACKGROUND

Scapular muscle endurance and core endurance reportedly influence shoulder injury risk. The exact relationship between scapular muscle endurance and core endurance, and how they impact one another in the healthy subjects remain unclear.

OBJECTIVE

To investigate the relationship between scapular muscle endurance and core endurance in healthy subjects.

METHODS

Fifty healthy volunteers (23 males, 27 females; mean age 20.42 ± 1.04 years) were participated in this study. Endurance of the serratus anterior and trapezius muscles was assessed using the scapular muscle endurance test. Sorensen test (endurance of trunk extensor muscles), trunk flexor endurance test, and side bridge test (endurance of lateral core muscles) were conducted to assess the core endurance. Pearson's product moment correlations examined relationships between scapular muscle endurance and each of the core endurance tests scores.

RESULTS

Scapular muscle endurance test scores showed a positive correlation with the side bridge test scores (r = 0.414; p = 0.003). No significant correlation was found between scapular muscle endurance test scores and the other core endurance tests scores (p > 0.05).

CONCLUSIONS

There appears to be a link between the scapular muscle endurance and lateral core muscles in healthy subjects; however, more research is needed to provide a definitive answer on the nature of this relationship. Further studies involving patients with shoulder pathology are warranted.

Do Verbal and Tactile Cueing Selectively Alter Gluteus Maximus and Hamstring Recruitment During a Supine Bridging Exercise in Active Females? A Randomized Controlled Trial

Context: Hip extension with hamstring-dominant rather than gluteus maximus-dominant recruitment may increase anterior femoracetabular forces and contribute to conditions that cause hip pain. Cueing methods during hip extension exercises may facilitate greater gluteus maximus recruitment. Objective: We examined whether specific verbal and tactile cues facilitate gluteus maximus recruitment while inhibiting hamstring recruitment during a bridging exercise. Design: Randomized controlled trial. Setting: Biomechanics laboratory. Participants: 30 young adult women (age 24 [3] y; BMI 22.2 [2.4] kg/m2). Intervention: Participants were tested over 2 sessions, 1 week apart, while performing 5 repetitions of a bridging exercise. At their second visit, participants in the experimental group received verbal and tactile cues intended to facilitate gluteus maximus recruitment and inhibit hamstring recruitment. Control group participants received no additional cues beyond original instructions. Main Outcome Measures: Gluteus maximus and hamstring recruitment were measured with surface electromyography, normalized to maximal voluntary isometric contractions (MVICs). Results: Gluteus maximus recruitment was unchanged in the control group and increased from 16.8 to 33.0% MVIC in the cueing group (F = 33.369, P < .001). Hamstring recruitment was unchanged in the control group but also increased from 16.5 to 29.8% MVIC in the cueing group (F = 6.400, P = .02). The effect size of the change in gluteus maximus recruitment in the cueing group (Cohen’s d = 1.5, 95% CI = 0.9 to 2.2) was not significantly greater than the effect size in hamstring recruitment (Cohen’s d = 0.8, 95% CI = 0.1 to 1.5). Conclusions: Verbal and tactile cues hypothesized to facilitate gluteus maximus recruitment yielded comparable increases in both gluteus maximus and hamstring recruitment. If one intends to promote hip extension by facilitating gluteus maximus recruitment while inhibiting hamstring recruitment during bridging exercises, the cueing methods employed in this study may not produce desired effects.

Trunk Muscle EMG During Intermediate Pilates Mat Exercises in Beginner Healthy and Chronic Low Back Pain Individuals

OBJECTIVE

The purpose of this study was to compare the electromyographic pattern of core muscles during intermediate Pilates mat exercises between healthy people and those with low back pain.

METHODS

We evaluated healthy participants (n = 19; mean ± standard deviation [SD]: age 28 ± 8 years, body mass 65 ± 10 kg, height 160.0 ± 9.1 cm) and a low back pain group (n = 13; mean ± SD: age 30 ± 9 years, body mass 67 ± 12 kg, height 170.0 ± 6.6 cm). Electromyographic analysis assessed the multifidus, external oblique, internal oblique, and rectus abdominis muscles during classical Pilates exercises (single leg stretch, criss-cross, and dead bug). We calculated the root mean square normalized by maximum voluntary contraction, and the time of peak activation was provided by a linear envelope and normalized by the total movement cycle.

RESULTS

The criss-cross exercise presented the highest values of root mean square for trunk flexors (rectus abdominis and oblique) compared with the other exercises, followed by the single leg stretch and the dead bug, which had similar muscle activation. The single leg stretch presented more activation of the rectus abdominis and oblique, whereas the criss-cross and dead bug created more activation of the oblique compared with the multifidus and rectus.

CONCLUSIONS

The Pilates exercises presented different muscle recruitment patterns, and allowed the activation of the lumbopelvic stabilizing muscles even in the first session for healthy individuals and those with chronic low back pain.

Trunk muscle activity during different variations of the supine plank exercise

BACKGROUND

Exercises providing neuromuscular challenges of the spinal muscles are desired for core stability, which is important for workers with heavy manual labour as well as people recovering from back pain.

PURPOSE

This study evaluated whether using a suspended modality increases trunk muscle activity during unilateral or bilateral isometric supine planks.

DESIGN

Cross-sectional.

METHODS

Twenty university students participated in this cross-sectional study. Each subject performed four different conditions: bilateral stable supine plank, unilateral stable supine plank, bilateral suspended supine plank and unilateral suspended supine plank. Surface electromyography (EMG) signals were recorded for the upper rectus abdominis (UP ABS), lower rectus abdominis (LOW ABS), external oblique (OBLIQ) and lumbar erector spinae (LUMB). Peak EMG of the filtered signals were normalized to the maximum voluntary isometric contraction (MVIC).

RESULTS

No differences between exercises were found for UP ABS, LOW ABS and OBLIQ muscle activity. The unilateral suspended supine plank provided the highest LUMB activity (20% of MVIC) whiles the bilateral stable supine plank provided the lowest activity (11% of MVIC).

CONCLUSIONS

The combination of unilateral variations with a suspended support provides the greatest LUMB muscle activity, while using these variations separately only provides advantages when compared with regular planks.

The effects of pelvic diagonal movements and resistance on the lumbar multifidus

[Purpose] The purpose of this study was to compare the effects of pelvic diagonal movements, made with and without resistance, on the thickness of lumbar multifidus muscles. [Subjects and Methods] Participants in this study were healthy subjects who had no musculoskeletal disorders or lumbar-related pain. Participants were positioned on their side and instructed to lie with their hip flexor at 40 degrees. Ultrasonography was used for measurement, and the values of two calculations were averaged. [Results] The thickness of ipsilateral lumbar multifidus muscles showed a significant difference following the exercise of pelvic diagonal movements. The results of anterior elevation movements and posterior depression movements also demonstrated significant difference. There was no significant difference in lumbar multifidus muscles thickness between movements made with and without resistance. [Conclusion] These findings suggest that pelvic diagonal movements can be an effective method to promote muscular activation of the ipsilateral multifidus. Furthermore, researchers have concluded that resistance is not required during pelvic diagonal movements to selectively activate the core muscles.

Relationship between flexion-rotation test and ultrasound thickness measurement of the abdominal muscles

OBJECTIVE

The purpose of this study was to investigate the relationship between flexion-rotation test and ultrasound (US) thickness measurement of the antero-lateral abdominal muscles.

DESIGN

Following ethical approval, a convenience sample of 55 subjects between the ages of 20 and 30 years participated in this study. Endurance of the abdominal muscles was measured using the flexion-rotation test in all subjects. US thickness measurement for the transversus abdominis (TrA), internal oblique (IO) and external oblique (EO) muscles was performed on the right side at rest in a supine position.

RESULTS

Pearson correlation coefficient between the variables of the study showed no significant relationship between the flexion-rotation test and US thickness measurements of the TrA (r = -0.03, P = 0.80), IO (r = -0.13, P = 0.32), and EO (r = -0.14, P = 0.31) muscles. The significance level of 0.05 was chosen.

CONCLUSION

It seems that there is no significant relationship between the flexion-rotation test and US measurement of abdominal muscles thickness.

Comparison of electromyographic activities of lumbar iliocostalis and lumbar multifidus muscles during stabilization exercises in prone, quadruped, and sitting positions

[Purpose] The purposes of this study were: 1) describe a hierarchy of electromyographic activity production, using percentage maximum voluntary contraction of lumbar iliocostalis and lumbar multifidus muscles during prone, quadruped and sitting exercises; and 2) identify optimal recruitment exercises for both lumbar iliocostalis as a global multi-segmental stabilizer and lumbar multifidus as a segmental stabilizer. [Subjects] Twelve healthy volunteers (six male and six female) aged 24 to 45 participated. [Methods] Surface electromyographic activity data were collected bilaterally from lumbar iliocostalis and lumbar multifidus muscles during exercises. [Results] Two-way ANOVA showed that prone extension, and prone alternate arm and leg lifting exercises produce a statistically significant difference in percent maximum voluntary contraction of lumbar iliocostalis and lumbar multifidus bilaterally compared to other exercises. Quadruped alternate arm and leg lifting exercises produce greater activity in lumbar multifidus muscle than sitting exercises [Conclusion] Prone exercises generate the greatest electromyographic activity and may be the most effective exercises for strengthening both lumbar iliocostalis and lumbar multifidus muscles. Quadruped alternate arm and leg lifting produces electromyographic activity at the recommended percent maximum voluntary contraction for training the lumbar multifidus in its role as a segmental stabilizer and is an effective training exercise for this goal.