Contemporary perspectives of core stability training for dynamic athletic performance: a survey of athletes, coaches, sports science and sports medicine practitioners

Diaphragm and core stabilization exercises in low back pain: A narrative review

INTRODUCTION

Core stabilization is a vital concept in clinical rehabilitation (including low back pain rehabilitation) and competitive athletic training. The core comprises of a complex network of hip, trunk and neck muscles including the diaphragm.

AIMS

The paper aims to discuss the role of the diaphragm in core stability, summarize current evidence and put forth ideal core training strategies involving the diaphragm.

METHOD

Narrative review RESULTS: The diaphragm has a dual role of respiration and postural control. Evidence suggests that current core stability exercises for low back pain are superior than minimal or no treatment, however, no more beneficial than general exercises and/or manual therapy. There appears to be a higher focus on the transversus abdominis and multifidi muscles and minimal attention to the diaphragm. We propose that any form of core stabilization exercises for low back pain rehabilitation should consider the diaphragm. Core stabilization program could commence with facilitation of normal breathing patterns and progressive systematic restoration of the postural control role of the diaphragm muscle.

CONCLUSION

The role of the diaphragm is often overlooked in both research and practice. Attention to the diaphragm may improve the effectiveness of core stability exercise in low back pain rehabilitation.

How safe are partial squats after the anterior cruciate ligament reconstruction? A finite element analysis

BACKGROUND

Partial squats are a part of many rehabilitation programs. Progress to deeper squats can only be performed through the partial squat position. However, squats safety, onset time, and rational depth are still controversial. Most previous studies have not considered the influence of posterior tibial slope (PTS) and anterolateral ligament (ALL) on the stress on the knee anatomical elements in partial squats.

METHODS

We have created the new comprehensive knee computer models, which considered muscle exertions while weight bearing 75, 100, 125, and 150 kg in partial squats, included the ALL, two variants of PTS (5° and 13.9°), and two variants of anterior cruciate ligament (ACL) (a native 6 mm double-bundle ACL and an 8 mm single-bundle ACL graft). Using the finite element analysis, we have analyzed stresses in 14 anatomical elements in each model in partial squats (55° knee flexion and 10° anterior tibia tilt).

RESULTS

PTS change from 5° to 13.9° in a partial squat increases stress 1.2-1.3 times on the native ACL and 1.3-1.4 times on the ALL. In the case of single-bundle ACL reconstruction, PTS growth from 5° to 13.9° results in stress increasing 1.2-1.3 times on the graft and 1.3-1.4 times on the ALL. Thus, increased PTS is a significant risk factor, especially in the early postoperative period. Weight-bearing predictably increases stress on the ACL, ALL, and other joint elements proportional to the weight growth. Patients with thinner grafts after the ACL reconstruction may already reach the risk level for graft rupture in a single load in partial squatting if they weigh 125 kg or more. The risk rises with increasing PTS angle or the patient's weight. Because of the reduction of the graft strength by six weeks after surgery by 27%, partial squats in six weeks are associated with forces that may exceed the maximal ACL load even in patients with 75 kg of weight without additional load.

CONCLUSION

In the early postoperative period, partial squats can put the ACL graft at risk of failure. This risk is proportional to the patient's weight and PTS angle, and inversely proportional to the graft thickness. The choice of physical therapy strategies after ACL reconstruction, exercises, and their initiation timing is complex and cannot be standardized for all patients. Factors like the thickness of the graft, the method of fixation, the patient's weight, the ALL insufficiency, the PTS angle, and the patient's goals in the short and long term should be considered when planning the rehabilitation program.

Abdominal wall tension increases using Dynamic Neuromuscular Stabilization principles in different postural positions

BACKGROUND

Intra-abdominal pressure (IAP) is an important mechanism stabilizing the spine and trunk. IAP regulation depends on the coordination of abdominal muscles, diaphragm and pelvic floor muscles.

OBJECTIVE

To determine the differences in abdominal wall tension (AWT) of various postural positions, first without any correction, then after verbal and manual instructions according to Dynamic Neuromuscular Stabilization (DNS) principles.

METHODS

In a cross-sectional observational study, thirty healthy individuals (mean age = 22.73 ± 1.91 years) were fitted with two Ohmbelt sensors contralaterally above the inguinal ligament and in the upper lumbar triangle. AWT was measured during five postural positions: sitting, supine with legs raised, squat, bear and hang position. First, spontaneous AWT was measured, then again after manual and verbal instructions following DNS principles.

RESULTS

AWT increased significantly with DNS instructions compared to spontaneous activation. Both sensors recorded significant increases (p < .01; Cohen's d = -1.13 to -2.06) in all observed postural situations. The increase in activity occurred simultaneously on both sensors, with no significant differences noted in pressure increases between the sensors. The greatest activation for both sensors occurred in the bear position. Significant increases in activity were identified for both sensors in the supine leg raise position and in the bear position compared to spontaneous activation in sitting (p < .001). There were no statistically significant differences (for both sensors) between women and men in any position.

CONCLUSION

The amount of AWT significantly increases after verbal and manual instructions according to DNS. The greatest abdominal wall activation was achieved in the bear position.

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

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

Effect of Core Balance Training on Muscle Tone and Balance Ability in Adult Men and Women

(1) Background: The amount of physical activity most adults perform is less than the recommended amount, and the resulting decrease in physical strength makes them vulnerable to various diseases. A decrease in muscle size and strength due to damage caused by disease or aging negatively affects functional strength. Muscle evaluation in adults can yield results that are predictive indicators of aging and unexpected disability. In addition, balance ability is essential to prevent falls and injuries in daily life and maintain functional activities. It is important to develop and strengthen balance in the lower extremities and core muscles to maintain and enhance overall body balance. This study aimed to analyze the effects of core balance training on muscle tone and balance ability in adults. (2) Methods: The participants of this study were 32 adult male and female university students (male: mean age = 21.3 ± 1.9 years, weight = 74.2 ± 12.6 kg, BMI = 23.4 + 2.5, n = 14; female: mean age = 21.0 ± 1.4 years, weight = 64.6 + 1.2 kg, BMI = 22.4 ± 2.4, n =18). Thirty-two adults (training group: 16, control group: 16; male: 16, female: 16) participated in the Myoton PRO (gastrocnemius lateral/medial, tibialis anterior), Pedalo balance system, and Y-balance test. (3) Results: The following results were obtained for muscle elasticity, stiffness, and dynamic/static balance ability after 10 weeks of core balance training. 1. There was no significant difference in muscle elasticity (gastrocnemius lateral/medial, tibialis anterior) (p < 0.05). 2. Muscle stiffness (gastrocnemius lateral/medial, tibialis anterior) significantly increased (p < 0.05). 3. Dynamic/static balance ability significantly increased (p < 0.05). (4) Conclusions: In future, data for the age and sex of various participants, should be accumulated by recruiting participants to study muscle characteristics, such as muscle elasticity and stiffness. Estimating the appropriate injury range and optimal exercise capacity is possible through follow-up studies. The findings can then be used as a basis for predicting injuries or determining and confirming the best time to resume exercise.

Short-term effects of lumbopelvic complex stability training in elite female road cyclists

OBJECTIVES

The purpose of this study was to determine the effects of short-term lumbopelvic stability training on muscular endurance and stability in elite female cyclists.

METHODS

Twenty-four female road cyclists were randomly allocated to a core training group (CTG, n=12) or control group (CG, n=12). In addition to their scheduled training the CTG performed a core training program, that consisted of 6 core exercises performed in a session every other day until a total of 8 training sessions were completed. The CG did not receive the core training program and completed their scheduled training. The lumbopelvic-hip complex was assessed pre- and post-core program included the following exercises: single leg deadlift (SLD), bird-dog (BD), plank test (PT), and side-bridge plank test (SPT).

RESULTS

In comparison to CG, CTG significantly improved the time to failure in PT, SPT-Left, and SPT-Right (p<0.05). Further, CTG resulted in a significant decrease in SLD (p<0.05) compared to CG for the three accelerometry measures.

CONCLUSION

The present results indicate that following 8 sessions of lumbopelvic stability training muscular endurance and core stability were enhanced.

Effects of a Specific Core Stability Program on the Sprint and Change-of-Direction Maneuverability Performance in Youth, Male Soccer Players

Although it is recommended to use sport-specific training programs to optimize performance, studies analyzing the effects of the core stability training with high levels of sport-specificity on athletic performance are insufficient and unclear. The objective of this study was to analyze the effects of the level of specificity of a CORE stability program on specific soccer actions. Fourteen youth players were randomly assigned to the specific core stability group (SCS; n = 7) or the general core stability group (GCS; n = 7). The eight-week intervention consisted of two weekly training sessions added to the usual soccer training. Both groups performed four CORE stability tasks. The SCS group followed the principle of sports specificity, while the GCS group performed CORE stability commons. Ten-meter linear sprinting (Sprint) and change-of-direction maneuverability (V-cut) were evaluated before and after the intervention programs. A statistically significant improvement was obtained in Sprint (d = 0.84 95% CI (0.22, 1.45), p = 0.008) and V-cut (d = 1.24 95% CI (0.52, 1.93), p < 0.001). At posttest, statistically nonsignificant differences were obtained between groups in Sprint (d = 1.03 95% CI (−0.25, 2.30), p = 0.082) and V-cut (d = −0.56 95% CI (−1.89, 0.78), p = 0.370). In conclusion, sprint and change-of-direction maneuverability were improved, but there was no superiority of any type of training.

Design and Validation of Multichannel Wireless Wearable SEMG System for Real-Time Training Performance Monitoring

Monitoring of training performance and physical activity has become indispensable these days for athletes. Wireless technologies have started to be widely used in the monitoring of muscle activation, in the sport performance of athletes, and in the examination of training efficiency. The monitorability of performance simultaneously in the process of training is especially a necessity for athletes at the beginner level to carry out healthy training in sports like weightlifting and bodybuilding. For this purpose, a new system consisting of 4 channel wireless wearable SEMG circuit and analysis software has been proposed to detect dynamic muscle contractions and to be used in real-time training performance monitoring and analysis. The analysis software, the Haar wavelet filter with threshold cutting, can provide performance analysis by using the methods of moving RMS and %MVC. The validity of the data obtained from the system was investigated and compared with a biomedical system. In this comparison, 90.95% ± 3.35 for left biceps brachii (BB) and 90.75% ± 3.75 for right BB were obtained. The output of the power and %MVC analysis of the system was tested during the training of the participants at the gym, and the training efficiency was measured as 96.87% ± 2.74.