Effect of soft lumbar support belt on abdominal oblique muscle activity in nonimpaired adults during squat lifting

The Effect of Volitional Preemptive Abdominal Contraction on Biomechanical Measures During A Front Versus Back Loaded Barbell Squat

Background

Weightlifting is growing in popularity among recreational and competitive athletes. The barbell back squat (BackS) is commonly included in these training programs, while the barbell front squat (FrontS) is commonly performed as a component of other lifts such as the power clean or clean and jerk, it is less commonly practiced in isolation.

Hypothesis/Purpose

The purpose of this study was to examine the effects of VPAC performance on trunk muscle and LE biomechanical responses during loaded BackS versus FrontS in healthy subjects.

Study Design

Controlled Laboratory Study.

Methods

Healthy male subjects with the ability to perform a sub-maximal loaded barbell squat lift were recruited. Subjects completed informed consent, demographic/medical history questionnaires and an instructional video. Subjects practiced VPAC and received feedback. Surface electromyography (sEMG) electrodes and kinematic markers were applied. Muscles included were the internal oblique (IO), external oblique (EO), rectus abdominis, iliocostalis lumborum (ICL), superficial multifidi, rectus femoris, vastus lateralis, biceps femoris, and gluteus maximus. Maximal voluntary isometric contractions established reference sEMG values. A squat one-rep-max (1RM) was predicted by researchers using a three to five repetition maximum (3RM, 5RM) load protocol. Subjects performed BackS trials at 75% 1RM while FrontS trials were performed at 75% BackS weight, both with and without VPAC. Subjects performed three repetitions of each condition with feet positioned on two adjacent force plates. Significant interactions and main effects were tested using a 2(VPAC strategy) x 2(squat variation) and 2(VPAC strategy) x 2(direction) within-subject repeated measures ANOVAs. Tukey's Post-Hoc tests identified the location of significant differences.

Results

Trunk muscle activity was significantly higher during FrontS versus BackS regardless of VPAC condition. (IO: p=0.018, EO: p<0.001, ICL: p<0.001) VPAC increased performance time for both squat variations (p=.0011), which may be associated with decreased detrimental force potential on the lumbar spine and knees. VPAC led to improved ability to maintain a neutral lumbar spine during both squat variations. This finding is associated with decreased detrimental force potential on the lumbar spine.

Conclusions

Findings could help guide practitioners and coaches to choose squat variations and incorporate VPAC strategies during their treatments and/or training programs.

Level of Evidence

Level 3©The Author(s).

Functional Training in Portuguese Firefighters: Impact of Functional Training With or Without Personal Protective Equipment

OBJECTIVE

To investigate the influence of specific functional training (FT) with and without personal protective equipment (PPE) and self-contained breathing apparatus (SCBA), on firefighters (FFs) physical fitness condition.

METHODS

Sixty FFs run a 24 weeks intervention, divided into three groups (EG1 training with PPE+SCBA; EG2 training with regular equipment, and Control Group). FFs anthropometric and physical fitness (PF) were assessed pre- and post-intervention.

RESULTS

Significant differences were found between the training groups and control group. Both training groups interventions were effective in improving PF and lean mass. However, EG1 presented a higher percentage of improvement.

CONCLUSION

This 24-week FT intervention improved participants' muscle strength, endurance, and power, and it led to increases in lean body mass. Regularly FT with PPE+SCBA helps FFs maintain a healthy general physical condition and develop optimum fitness levels related to firefighting specific tasks, specially torso muscular endurance.

Strength training improves the respiratory muscle strength and quality of life of elderly with Parkinson disease

BACKGROUND

The progression of Parkinson disease can lead to respiratory muscle weakness, reduced peak expiratory flow and quality of life (QoL). The aim was to evaluate the effects of strength training on levels of respiratory muscle strength, peak expiratory flow and QoL of elderly with Parkinson disease.

METHODS

A total of 28 patients were randomized into one of two groups: the control group (CG) comprised 16 participants, and the strength training group (STG) comprised 12 participants. All subjects maintained the standard pharmacological treatment for Parkinson disease, and the intervention group participated in a 16-week strength training program. The primary outcome was the measurement of respiratory muscle strength.

RESULTS

The STG showed improved values of maximum inspiratory pressures (36.11±11.82 to 52.94±24.17; P=0.01), maximum expiratory pressures (56.67±22.08 to 71.04±33.71; P=0.03) and QoL (41.75±20.33 to 34±20.92; P=0.0054); there was no significant difference in the peak expiratory flow (336.11±198.04 to 380±229.57; P=0.09). The CG showed significantly decreased values of peak expiratory flow (336.88±183.40 to 279.37±125.12, P=0.02) and non-significant changes in the other variables.

CONCLUSIONS

Sixteen weeks of strength training improves the inspiratory and expiratory muscle strength and QoL of elderly with Parkinson disease. These findings suggest that strength training could be considered an adjunct therapeutic intervention for elderly with Parkinson disease.

Influence of elastic lumbar support belts on trunk muscle function in patients with non-specific acute lumbar back pain

Background

A well-known supportive treatment for acute nonspecific back pain, elastic back support belts, are valued for their ability to accelerate natural self-healing, but there are concerns of a deconditioning effect due to their reliance on passive stabilization.

Methods

To evaluate the systematic effects of elastic abdominal belts on the trunk musculature, a total of 36 persons with acute lumbar back pain (no longer than one week) were divided into two groups: an abdominal belt wearing group (B) and a non-abdominal belt wearing control group (C). All were examined over a period of three weeks at three time points: T1 just after assignment, T2 one week later, and T3 further two weeks later. Surface EMG (sEMG) was used to record trunk muscle activation when walking on a treadmill at walking speeds of 2, 3, 4, 5, and 6 km/h. Similarly, pain intensity (VAS) and functional impairment (ODI) over time were recorded in both groups.

Results

Over the observation period, a slight advantage for decreased pain intensity (C: p<0.05 T2 vs. T1; B: p<0.01 T2 vs. T1, p<0.05 T3 vs. T1) and decreased functional impairment (Cohen's d vs. T1, C: T2 0.45, T3 0.86; B: T2 1.1, T3 1.0) was observed for the belt group. For the belt group both oblique abdominal muscles exhibited significantly lower sEMG throughout the observation period (external abdominal oblique muscle: (T1), T2, (T3), internal abdominal oblique muscle: T1, (T2), (T3)) and the sEMG for the back muscles ranged from unchanged to slightly elevated for this group, but never reached statistical significance.

Discussion

The reduced abdominal amplitude levels in the belt group likely result from the permanent elastic stabilization provided by the belt: the required elevated intra-abdominal pressure to enhance spinal stability is then provided by lessened abdominal muscle activity complemented by the belt’s elastic support. With regard to the back muscles, the belt, due to its movement-restricting effect, tends to activate the paravertebral musculature. In this respect, the effect of elastic abdominal belts on the trunk muscles is not uniform. Therefore, the present results suggest that the effect of elastic abdominal belts appears to be more of a temporary neutral alteration of trunk muscle coordination, with some trunk muscles becoming more active and others less, and not a case of uniform deconditioning as is suspected.

Can lumbosacral orthoses cause trunk muscle weakness? A systematic review of literature

BACKGROUND

Wearing lumbosacral orthosis (LSO) is one of the most common treatments prescribed for conservative management of low back pain. Although the results of randomized controlled trials suggest effectiveness of LSO in reducing pain and disability in these patients, there is a concern that prolonged use of LSO may lead to trunk muscle weakness and atrophy.

PURPOSE

The present review aimed to evaluate available evidence in literature to determine whether LSO results in trunk muscle weakness or atrophy.

STUDY DESIGN

This is a systematic review.

METHODS

A systematic search of electronic databases including PubMed, Scopus, ScienceDirect, and Medline (via Ovid) followed by hand search of journals was performed. Prospective studies published in peer-reviewed journals, with full text available in English, investigating the effect of lumbar orthosis on trunk muscle activity, muscle thickness, strength or endurance, spinal force, and intra-abdominal pressure in healthy subjects or in patients with low back pain, were included. Methodological quality of selected studies was assessed by using the modified version of Downs and Black checklist. This research had no funding source, and the authors declare no conflicts of interest-associated biases.

RESULTS

Thirty-five studies fulfilled the eligibility criteria. The mean and standard deviation of the quality score was 64±9.7%. Most studies investigating the effect of lumbar orthosis on electromyographic activity (EMG) of trunk muscles demonstrated a decrease or no change in the EMG parameters. A few studies reported increased muscle activity. Lumbosacral orthosis was found to have no effect on muscle strength in some studies, whereas other studies demonstrated increased muscle strength. Only one study, which included ultrasound assessment of trunk muscle stabilizers, suggested reduced thickness of the abdominal muscles and reduced cross-sectional area of the multifidus muscles. Out of eight studies that investigated spinal compression load, the load was reduced in four studies and unchanged in three studies. One study showed that only elastic belts reduced compression force compared to leather and fabric belts and ascribed this reduction to the elastic property of the lumbar support.

CONCLUSION

The present review showed that the changes in outcome measures associated with muscle work demands were inconsistent in their relation to the use of lumbar supports. This review did not find conclusive scientific evidence to suggest that orthosis results in trunk muscle weakness.

Effect of wearing a lumbar orthosis on trunk muscles: study of the muscle strength after 21days of use on healthy subjects

INTRODUCTION

Randomized and controlled study of clinical evaluation of medical device in healthy subjects.

OBJECTIVE

To evaluate the effect of wearing an elastic lumbar support, frequently used in low-back pain prevention or treatment, on the trunk flexors and extensors muscle strength on healthy subjects.

SUMMARY OF BACKGROUND DATA

The long-term use of a lumbar orthosis is still suspected of weakening on the trunk muscles. The results in the existing literature are contradictory but don't seem to confirm this.

METHODS

Trunk muscle isokinetic and isometric strength measured before and after the wearing of an elastic orthosis over a period of 21days by healthy subjects with a control group without orthosis.

RESULTS

There were 20 healthy subjects using orthosis and 9 controls. No changes in isokinetic and isometric strength were observed except for the endurance parameter on extensors: it was significantly more important before than after the lumbar support use (p=0.033).

CONCLUSION

These results disprove any negative effects on muscle strength and add to the existing literature which argues for a more customized prescription of lumbar orthosis depending on the potential muscle strength of the subject.

Maximal Strength Training of the Legs in COPD

PURPOSE

A diminished mechanical efficiency (work/O2 consumed) accompanies chronic obstructive pulmonary disease (COPD), and increased mechanical efficiency has been attained by maximal strength training (MST) with an emphasis on the maximal rate of force mobilization in the concentric phase in healthy subjects. This study combined these observations and evaluated the impact of short-term MST on patients with COPD.

METHODS

Twelve patients with COPD (FEV1 = 1.1 +/- 0.1) were pretested and then randomly assigned to either an MST group (N = 6) or a normal activity control group (N = 6). Within each MST training session (three times per week for 8 wk), patients performed four sets of seated leg presses with a focus on the rate of force development at an intensity that only allowed the performance of five repetitions.

RESULTS

Patients who performed MST significantly improved their rate of force development (105 +/- 22.8%), mechanical efficiency (32 +/- 7%), and FEV1 (21.5 +/- 6.8%), whereas these variables were unchanged in the controls. Neither group changed either peak oxygen consumption (VO2peak) or body mass.

CONCLUSION

In combination with the observed improvement in FEV1, these data certainly support the therapeutic role for MST in the treatment of COPD.

The encircling mesh in abdominal wall surgery: rationale and technical details of a dorso-ventral physiological restoration

We describe a new, functional surgical technique, known as 'encircling mesh', designed to address abdominal wall problems. The rationale of the procedure is to connect the anterior and posterior trunk muscle compartments by means of a purpose built polypropylene mesh that encloses a belt shifted posteriorly across the spine subcutaneously, through use of a disposable introducer. The technical details and a case presentation, with specific references to the cosmetic and functional outcomes are described.