Progressions of core stabilization exercises based on postural control challenge assessment

Exercise Intensity Progressions and Criteria to Prescribe Core Stability Exercises in Young Physically Active Men: A Smartphone Accelerometer-Based Study

ABSTRACT

Heredia-Elvar, JR, Juan-Recio, C, Prat-Luri, A, Barbado, D, Ríos-Calonge, Jdl, and Vera-Garcia, FJ. Exercise intensity progressions and criteria to prescribe core stability exercises in young physically active men: a smartphone accelerometer-based study. J Strength Cond Res 38(2): 266-273, 2024-The establishment of core stability (CS) exercise intensity progressions in sport and clinical settings is normally based on subjective criteria. Therefore, this study aimed to develop exercise intensity progressions for some of the most common CS exercises through smartphone accelerometry and to analyze the effect of the subjects' lumbopelvic postural control on these progressions. Fifty-seven healthy young physically active male students performed 7 isometric variations of front bridge, back bridge, side bridge, and bird-dog exercises with a smartphone accelerometer placed on the pelvis. Mean pelvic accelerations were calculated during each variation to evaluate the lumbopelvic postural control challenge imposed on the subjects as an index of exercise intensity of difficulty. For the bridge exercises, long bridging produced higher pelvic accelerations than short bridging, bridging with single-leg support was more intense than bridging with double-leg support (even with both legs on a hemisphere ball for the back and front bridge), and the most difficult variations were those performed on a Swiss ball, mainly the variations with single-leg support. For the bird-dog exercise, the 2-point positions were more intense than the 3-point positions, the variations performed with a knee on the hemisphere ball produced higher pelvic accelerations than similar variations performed with the forearm on the hemisphere ball, and the variations with limb motions generated higher pelvic accelerations than similar variations performed without limb motions. Although the CS exercise progressions were very similar across subjects, our results showed the need to individualize the prescription of the CS exercise progressions based on the subjects' lumbopelvic postural control level.

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.

Smartphone accelerometry for quantifying core stability and developing exercise training progressions in people with multiple sclerosis

BACKGROUND

Core stability exercise programs have become popular in recent years for preserving balance and functional independence in people with multiple sclerosis (PwMS); however, their real impact is not well-known as the main intervention target (i.e., core stability) theoretically responsible for balance or functional improvements is not measured. The objective of this study was to test the reliability of accelerometers integrated into smartphones for quantifying core stability and developing exercise progressions in PwMS.

METHODS

Twenty participants with MS [age: 47.5±8.0 years; height: 1.62±0.07 m; mass: 63.4±10.9 kg; EDSS: 3.0 (1.5-6)] participated voluntarily in this study. CS was assessed in different variations of the front, side, and back bridges and bird-dog exercises by measuring the mean lumbopelvic acceleration in two testing sessions, separated by one week. Relative and absolute reliability of lumbopelvic acceleration of those exercise variations performed by more than 60% of the participants was analyzed by the intraclass correlation coefficient (ICC_3,1), and the standard error of measurement (SEM) and the minimal detectable change (MDC), respectively. Repeated measures ANOVAs were performed to detect a potential learning effect between test-retest assessments. Statistical significance was set at p < 0.05.

RESULTS

Reliability analyses revealed that good to excellent relative and absolute scores (0.85<ICC<0.96; 7.8%≤SEM≤19.2%; 21.6%≤MDC≤53.2%) for the mean lumbopelvic acceleration obtained during 10 of the 12 CS exercise variations performed by more than 60% of the participants. A non-significant between-session learning effect was detected in all the variables considered (all p values >0.05).

CONCLUSION

Smartphone accelerometry seems a low cost, portable and easy-to-use tool to objectively and reliably track core stability changes in PwMS through. However, in spite of the popularity of bridging and bird-dog exercises, only the short and long bridges and the three-point bird-dog positions proved feasible for most participants. Overall, this study provides useful information to evaluate and guide the prescription of core stability exercise programs in PwMS with mild-to-moderate impairment.

Effect of Progressive Postural Control Exercise Versus Core Stability Exercise in Young Adults with Chronic Low Back Pain: A Randomized Controlled Trial

INTRODUCTION

This study aimed to investigate the effects of progressive postural control exercise (PPCE) vs core stability exercise (CSE) in patients with chronic low back pain (CLBP).

METHODS

A total of 34 young-adult participants with CLBP were randomly assigned to two groups (the PPCE group and the CSE group). They received instructions for two different exercise training regimens persisting over 8 weeks. Before, after, and at 6 months after the intervention, the participants were evaluated on the basis of pain intensity (VAS), degree of dysfunction (ODI and RMDQ), contractility of transversus abdominis (TrA) and lumbar multifidus (MF), as well as the ability to control static posture.

RESULTS

There was no significant difference between the results of the PPCE group and the CSE group. At the 6-month follow-up after the 8-week treatment, the scores of VAS, ODI, and RMDQ in the two groups decreased significantly compared to before (p < 0.05). The percentage change in thickness of bilateral TrA and left MF (p < 0.05) was elevated and the sway area of center of pressure during static stance tasks with eyes opened (p < 0.05) was decreased in both groups.

CONCLUSION

In the short term, PPCE provides positive effects similar to those of core stability exercise in patients with CLBP. The effective mechanism of PPCE might be the consequence of neuromuscular plasticity and adaptation adjustments. PPCE enriches the choices of treatment for CLBP.

CLINICAL TRIAL REGISTRATION

The trial was registered at www.chictr.org.cn , identifier ChiCTR2100043113.

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.

Effects of core training on dynamic balance stability: A systematic review and meta-analysis

Core stability has a strong relationship with dynamic balance stability (DBS). The purpose of this review with meta-analysis was to analyse the effects of core training programmes from different studies on DBS. A literature search was performed using different databases. Subgroups analyses on duration, training frequency, total sessions, chronological age, training status, equipment and movements were performed. A random-effects model for meta-analyses was used. Thirteen studies were selected for the systematic review and 10 for the meta-analysis, comprising 226 participants. A moderate effect was noted for core training on DBS (p < 0.001; ES = 0.634). Greater DBS improvements were found in core training interventions with ≤6 weeks (ES = 0.714), after high volume (ES = 0.787) and more frequent interventions (ES = 0.787), as well as in younger participants (ES = 0.832). In addition, body weight exercises may be better than med ball, swiss ball or band resisted exercises. Core training improves DBS among athletes and a non-trained population, creating a more solid stable base that allows better lower extremity movements. This could be more effective considering different modulators ≤6 weeks intervention, >2 sessions per week, >17 total sessions, body weight core programmes and applied to ≤18.0 years old.

Observational Screening Guidelines and Smartphone Accelerometer Thresholds to Establish the Intensity of Some of the Most Popular Core Stability Exercises

The lack of training load control, mainly exercise intensity, is one of the main limitations of core stability (CS) programs, which makes the training individualization and the analysis of the dose-response relationship difficult. The objectives of this study were to assess the inter-and intra-rater agreement when using new observational screening guidelines to decide if a core stability exercise represents an adequate training intensity level for a given participant. Besides, the relationship between experts' ratings based on these criteria and pelvic accelerations recorded with a smartphone accelerometer was also analyzed. Ten healthy physically active participants with a smartphone accelerometer placed on their pelvis were video-taped while performing a progression of seven variations of the front bridge, back bridge, side bridge and bird-dog exercises. Two expert and four non-expert raters watched the videos and used the observational screening guidelines to decide for each exercise variation if it represented an adequate training intensity level or not. In order to analyze the inter-and intra-rater agreement, several Kappa (κ) statistics were used. Receiver operating characteristic (ROC) curves to explore if the accelerometry allowed to establish pelvic acceleration thresholds representing the minimum level of exercise intensity for CS training. Cut-off acceleration values were calculated balancing sensitivity (Se) and 1-specifity (1-Sp) indexes (i.e., Youden index) or minimizing 1-Sp. The intra-and inter-rater analysis showed a substantial-high level of agreement with a prevalence-adjusted bias-adjusted Kappa > 0.69. The ROC curves showed that the acceleration thresholds for the bridging exercises were very similar, with global cut-off values of 0.35 m/s² (Se = 82%; 1-Sp = 15%) when using the Youden Index and of 0.50 m/s² when minimizing 1-Sp (Se = 31%), whilst the bird-dog exercise showed lower cut-off values (Youden Index: 0.21 m/s², Se = 90%, 1-Sp = 16%; minimizing 1-Sp: 0.32 m/s², Se = 40%). Overall, this study provides observational screening guidelines and smartphone accelerometer thresholds to facilitate the decision-making process when setting the intensity of some of the most popular core stability exercises in young physically active individuals.

A self-oblique exercise that activates the coordinated activity of abdominal and hip muscles-A pilot study

The importance of an interaction between trunk stability muscles and hip muscle function has been suggested. However, reported exercises rarely act on the trunk and hip muscles simultaneously. Here, we devised an abdominal oblique and hip muscle exercise, the Self-oblique exercise (SOE). We examined whether SOE activated abdominal and hip muscles in the supine and half-kneeling positions, compared with abdominal crunch (AC) and plank exercises; and whether participants could modulate the exercise load. Participants were 20 healthy males with some sports experience such as football and baseball on average 10.5 ± 4.0 years. Participants applied self-pressure to their right thighs using the contralateral upper limb with 40% or 70% of the maximum force in Supine SOE and Half- kneeling SOE. The following abdominal and hip muscles were measured using surface electromyography: bilateral external obliques (EO), bilateral internal obliques (IO), right rectus abdominis, right gluteus medius (GMed), and right adductor longus (ADD). All evaluated muscle groups showed significant differences between exercises (p < 0.001). Supine SOE-70% showed 80.4% maximal voluntary contraction (MVC) for left EO (p < 0.017), 61.4% MVC for right IO (p < 0.027), 24.3% MVC for GMed (p < 0.002), and 42.4% MVC for ADD (p < 0.004); these were significantly greatest among all exercises. Muscle activity during Supine SOE-70% was greater than that during Supine SOE-40%. Similarly, Half-kneeling SOE-40% promoted abdominal and hip muscle exertion, and showed more significant activity in GMed (p < 0.006) and ADD (p < 0.001) than AC and plank. SOE could activate abdominal and hip muscles depends on the pressure applied by upper limb. Also, SOE allows participants to modulate the exercise load in a self-controlled step by step manner. Modulation of the exercise load is difficult in AC or plank compared to SOE, and AC or plank cannot obtain simultaneous oblique and hip muscle activity. SOE could be practiced anywhere, in various positions, without any tools.

Different Gymnastic Balls Affect Postural Balance Rather Than Core-Muscle Activation: A Preliminary Study

Background: In proprioceptive training, unstable devices produce multidirectional perturbations that must be counterbalanced by the postural control systems and core-muscle activation. We investigated whether different sizes and shapes of three gymnastic balls could affect core-muscle activation and postural balance when performing the same exercise. Methods: Eleven young healthy subjects were assessed on the balls, assuming two body postures (bipedal seated and unipedal seated) and performing a dynamic exercise. Two balls were spherical with different diameters, and one was ovoid. Postural balance and muscle activation were assessed through center of pressure (CoP)-related parameters and surface electromyography. Results: Statistical analysis showed a significant effect of the gymnastic balls (p < 0.001) and the body postures (p < 0.001) for the CoP-related parameters, with the ovoid shape and the bipedal sitting representing the easiest conditions. Core-muscle activation was affected only by body postures, with a higher activation in the unipedal sitting (p < 0.01). In the dynamic exercise, significant differences were only detected for the CoP-related parameters (p < 0.001). Conclusions: The shapes and sizes of the gymnastic balls produced different degrees of destabilization under the same body posture but left the core-muscle activation unaltered. In the dynamic exercise, the conformation of the balls did not represent the main determinant in producing destabilizing effects.