Core training and performance: a systematic review with meta-analysis

Effect of unilateral and bilateral plyometric training on jumping, sprinting, and change of direction abilities: a meta-analysis

BACKGROUND

Plyometric training is a commonly employed method to enhance explosive strength in athletes. However, to date, no study has provided a comprehensive and systematic evaluation of the effects of unilateral (UNI) versus bilateral (BI) plyometric training.

OBJECTIVES

This meta-analysis investigates the impact of UNI and BI plyometric training on jumping, sprinting, and Change of Direction (COD) abilities.

STUDY ELIGIBILITY CRITERIA

To be eligible for inclusion in the meta-analysis, the study had to be:(1)healthy individuals; (2)UNI and BI plyometric training ; (3)conducted on rigid surfaces; (4)the outcome indicators were jumping ability, sprinting, and change of direction ability; (5)randomized controlled trials (RCTs).

STUDY APPRAISAL AND SYNTHESIS METHODS

We used the random-effects model for meta-analyses. Effect sizes (standardized mean difference), calculated from measures of horizontally oriented performance, were represented by the standardized mean difference and presented alongside 95% confidence intervals (CI).

DATA SOURCES

PubMed, Web of Science, Scopus, ProQuest, CNKI and Google Scholar.

RESULTS

A total of 11 papers met the inclusion criteria. The meta-analysis revealed that UNI contrast training was more effective than BI contrast training in improving single-leg jump performance (ES = 0.53, 95% CI: 0.02-1.04; Z = 2.05, p = 0.04), double-legs jump performance (ES = -0.07, 95% CI: -0.23-0.09; Z = 0.88, p = 0.38),sprint performance (ES = -0.04, 95% CI: -0.07--0.01; Z = 2.32, p = 0.02), as well as COD (ES = - 0.08, 95% CI: - 0.12 to - 0.03; Z = 3.29, p = 0.001 < 0.01). Conversely, BI contrast training showed a greater effect on bilateral jump performance (ES = -0.07, 95% CI: -0.12--0.03; Z = 3.39, p = 0.0007). Training with low-ground-contact frequencies (LGCF, fewer than 900 contacts) was found to significantly enhance vertical jump performance (ES = 0.64, 95% CI: 0.01-1.27; Z = 2.00, p = 0.05).

CONCLUSIONS

UNI and BI plyometric training offer modality-specific benefits for enhancing single-leg jumping, sprinting, and COD performance, whereas BI is more effective for optimizing bilateral jump performance. The LGCF protocol significantly enhances vertical jump performance.

The Effect of the Addition of Core Exercises to Supervised Physiotherapy in Patients With Subacromial Impingement Syndrome

Background

Weakness of the rotator cuff has been reported in patients with subacromial impingement syndrome (SIS). A novel therapeutic approach proposes adding exercises for the core musculature to aid in functional recovery in these patients.

Purpose

The aim of this study was to assess the short-term effects of adding a core exercise program to supervised physiotherapy on improve lateral rotator strength and functional outcomes in patients with SIS.

Study Design

A pre-post single-group study.

Methods

A total of 47 participants with SIS were recruited. All patients were treated with five weeks of supervised physiotherapy plus a core exercise program. The primary outcomes were isometric lateral rotator strength and grip strength, measured with a dynamometer. Secondary outcomes included muscular endurance assessed with the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST), shoulder function with the Constant-Murley (CM) questionnaire, and pain intensity reported using the Visual Analog Scale (VAS). Need a brief statement of statistical approach.

Results

At end of the five week intervention, isometric lateral rotator strength showed an increase of 9.2 kg (d = 2.1; p < 0.001) and grip strength an increase of 10.6 kg (d = 2.4; p < 0.001). The CKCUEST showed an increase of 5.6 repetitions (d = 3.7; p < 0.001), the CM questionnaire showed an increase of 30.3 points (d = 4.9; p < 0.001) and the VAS showed a decrease of 3.9 cm (d = 6.0; p < 0.001). All outcomes showed large effect sizes and statistically significant differences.

Conclusion

In the short term, adding a core exercise program to supervised physiotherapy showed statistically and clinically significant differences in lateral rotator strength and functional outcomes in patients with SIS.

Level of Evidence

Level 3.

The effects of strength and conditioning interventions on serve speed in tennis players: a systematic review and meta-analysis

Background

Tennis performance is highly influenced by serve speed. This review aimed to evaluate and quantitatively compare the efficacy of popular strength and conditioning (S&C) training methods in enhancing the speed of the ball in the serves of tennis players.

Methods

Following PRISMA guidelines, a systematic search was conducted in the Scopus, Web of Science, SportsDiscuss, and PubMed databases without date constraints, up to July 2024. Studies included in this meta-analysis met PICOS criteria: a) randomized controlled trials with healthy tennis players, b) isolated or combined S&C training programs, c) evaluation of tennis serve speed, and d) adequate data to compute effect sizes (ESs). The PEDro scale was used to assess methodological quality.

Results

Out of 271 identified papers, 16 studies of moderate to high quality were included in the meta-analysis. Resistance training demonstrated a small but significant effect on serve speed (ES = 0.53; p < 0.001), while multimodal training exhibited a moderate and significant effect (ES = 0.79; p = 0.001). However, core training did not have a significant effect on serve speed (ES = 0.32, p = 0.231).

Conclusion

The findings suggested that S&C interventions, including resistance and multimodal training, were beneficial for increasing serve speed in tennis players. Further high-quality research is recommended to confirm this conclusion.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_ record.php?RecordID=519790, identifier CRD42024519790.

Effects of a Specific Trunk and Shoulder Strength Training Program on Throwing Velocity and Accuracy: A Study Among Hungarian First-League Female Handball Players

The aim of the study was to record shoulder and trunk stability of elite female handball players and to investigate their effect on throwing velocity and accuracy. 151 female handball players (9 teams in total) from the Hungarian first league participated in a mid-season conditional survey. The study included tests of trunk and shoulder stability, and measurements of factors affecting shoulder stability, as well as throwing speed and throwing accuracy. After the conditional survey, 18 players were selected for the intervention group (IG) and 18 players for the control group (CG). Significant relationships were found between the medial stability of the shoulder joint (Y-balance) and throwing accuracy (upper right corner) (r = 0.766; p < 0.001), throwing accuracy (upper left corner) (r = 0.729; p < 0.001), total throwing accuracy (r = 0.907; p < 0.001). The IG showed significant improvement in trunk stability (p < 0.001), shoulder joint stability (p < 0.001), throwing velocity (p < 0.001), and throwing accuracy (p = 0.002), compared to the CG. These findings support the idea that trunk and shoulder stability are related to throwing performance of female handball players. Measuring and training these aforementioned factors, particularly medial shoulder stability, may be a valuable adjunct to improving throwing accuracy and throwing velocity.

The effects of aerobic gymnastics training on performance-related variables in an elite athlete: a 2-year follow-up study

This study investigates individual performance adaptations on 2 years of training between European Aerobics Championships. An elite, 22-year-old aerobic gymnast performed postural coordination test, Y-Balance test, squat and countermovement jumps, 60 s test of repeated jumps, an isokinetic leg muscle strength test, and the Wingate test. Postural stability and flexibility improved in terms of increased distance achieved in the Y-Balance test in the anterior (by 6.3%), posteromedial (by 2%), and posterolateral (by 4.8%) directions. Lower limb muscular endurance also increased, which can be corroborated by a reduced fatigue index in the 60 s test of repeated jumps (from 42% to 27% after the 1st and to 22% after the 2nd year of training). In addition, mean power increased during dominant (by 23.2% at 60°/s and by 18.5% at 180°/s) and non-dominant leg extension (by 4.9% at 180°/s and by 15.5% at 300°/s), plus dominant leg flexion (by 2.0% at 60°/s and by 6.9% at 300°/s). Similarly, peak torque/body weight ratio increased during dominant (by 24.9% at 60°/s, by 11.5% at 180°/s, and by 2.1% at 300°/s) and non-dominant leg extension (by 0.5% at 60°/s and by 6.4% at 300°/s), plus dominant leg flexion (by 1.7% at 60°/s and by 5.4% at 300°/s). However, 2 years of training failed to show any significant improvements in the explosive power of lower limbs and anaerobic performance. These findings indicate that general aerobic gymnastics training without any specific inputs leads to performance adaptation, namely, in abilities closely related to competition routine (dynamic balance and strength endurance of lower limbs).

Effect of core strength training on the badminton player's performance: A systematic review & meta-analysis

BACKGROUND

Core strength training (CST) has been shown to improve performance in several sports disciplines. CST is recognized as one of the crucial elements that enhance athletic performance, particularly impacting badminton skills. Despite its popularity as a strength training method among badminton players, there is a lack of comprehensive studies examining the effectiveness of CST on the performance of these athletes.

OBJECTIVE

This study aims to ascertain CST's effects on badminton players' performance.

METHOD

This study followed PRISMA principles and conducted comprehensive searches in well-known academic databases (SCOPUS, Pubmed, CNKI, Web of Science, Core Collection, and EBSCOhost) up to August 2023. The inclusive criteria were established using the PICOS framework. Following their inclusion based on PICOS criteria, the selected studies underwent literature review and meta-analysis. The methodological quality of the assessments was evaluated using Cochrane Collaboration's risk of bias tools bias risk tools and recommendations for a graded assessment, development, and evaluation.

RESULTS

The analysis included participants aged 10-19 years from 13 studies of moderate quality, totaling 208 individuals. The CST intervention s lasted between 4 to 16 weeks, with a frequency of 1 to 4 sessions per week and each session lasting 20 to 120 minutes. Sample sizes across these studies ranged from 8 to 34 participants. According to the meta-analysis, CST significantly influenced badminton performance, particularly in areas of explosive power (ES = 0.03 P = 0.04), front-court skill (ES = 2.53, P = 0.003), and back-court skill (ES = 2.33, P = 0.002).

CONCLUSION

CST enhances badminton players' fitness (strength, power, balance, and stability), in situ (front/back-court) skills, and movement position hitting. However, its effects on speed, endurance, agility, flexibility, and coordination are unclear, revealing a research gap. The precise benefits of CST, especially on flexibility and specific hitting skills (smashes, clears, drives, net shots, crosscourt, push, and lift shots), need more investigation. Additionally, research on CST's impact on female athletes is significantly lacking.

The reliability, variability and minimal detectable change of multiplanar isometric trunk strength testing using a fixed digital dynamometer

Trunk strength plays a vital role in athletic performance, rehabilitation and general health, however, current assessment methods are expensive, non-portable or unreliable. This study aimed to investigate the within- and between-session reliability, variability, standard error of measurement and minimal detectable change (MDC) of trunk strength in the sagittal (flexion and extension) and frontal planes (left and right lateral flexion) using a fixed digital dynamometer. Eighteen participants (ten men and eight women) attended two sessions separated by 7 days. Participants were fitted with a trunk harness which was secured to an immovable base via a digital dynamometer. Three maximal voluntary isometric contractions were completed across four positions (prone, supine, left-side recumbent and right-side recumbent, respectively) on a glute-hamstring raise machine. All positions demonstrated excellent reliability and low variability within session (ICC: 0.95-0.98; CV: 5-7%) and between sessions (ICC: 0.98-0.99; CV: 4-6%), across all positions. The between-session MDC ranged from 8% (prone) to 13% (right-side recumbent), translating to absolute values between 2.9 and 3.2 kg across all positions. Maximal isometric force testing using a fixed digital dynamometer provides reliable measurements of multiplanar trunk strength, providing a practical method for use in clinical practice.

The effect of 12-week core strength training on dynamic balance, agility, and dribbling skill in adolescent basketball players

Purpose

The purpose of the study was to examine the impact of core strength training on the dynamic balance, agility, and dribbling ability of adolescent basketball players.

Methods

A randomized controlled between-subjects design was employed. Forty-four male adolescent basketball players (aged 14.41 ± 3.22 years) were randomly divided into two groups: the core strength training (CST) group and the conventional training (CT) group. The CST program included 1-h sessions, three times/week for 12 weeks. In contrast, the CT group provided a thorough physical training program that targeted general conditioning rather than focusing solely on core strength. Three measurements were used to evaluate performance in players: the Star Excursion Balance Test, the Illinois Agility Test, and the Dribbling Test conducted at T0 (week 0), T1 (week 6), and T2 (week 12), respectively.

Results

Compared to the CT group, the CST group showed a greater improvement (p < 0.05) in dynamic balance, particularly in the anterior, posteromedial, and posterolateral directions, with significant interaction effects (p < 0.05) observed in these measures. Additionally, Bonferroni post-hoc revealed that the CST group demonstrated notably better agility (p < 0.05) at T2; whereas, improvements in dribbling skills were significant (p < 0.05) within the CST group from T1 to T2, but not when compared to the CT group (p > 0.05).

Conclusion

The 12-week CST program significantly improved dynamic balance, agility, and dribbling skills in adolescent basketball players, demonstrating its potential as a valuable training component. Future research should explore CST's impact on other sport-specific elements and its applicability to female players.

Influence of trunk rotator strength on rotational medicine ball throwing performance

BACKGROUND

The strength of the trunk musculature plays an essential role in performance. The aims of this study were to analyze the relationship between the strength of the trunk rotation muscles with rotational medicine ball throwing velocity and distance, to study differences between sex in rotational medicine ball throwing and to compare the asymmetries of trunk rotational strength and rotational medicine ball throwing.

METHODS

Thirty physically active college students participated on the study. Horizontal and low cable woodchop exercises were assessed with a functional electromechanical dynamometer and throwing was measured with a radar and a measuring tape. A Pearson's correlation coefficient was calculated for the relation between trunk rotational strength and rotational medicine ball throwing. Independent samples t-test was performed to determine the differences between sex in rotational medicine ball throwing and a paired samples t-test was performed to study the asymmetries.

RESULTS

Large and very large correlations were obtained between trunk rotational strength and rotational medicine ball throwing (r=0.68-0.79). Significant differences and a large effect size were found between males and females for all throwing velocity and throwing distance variables (P<0.05; ES>0.90) and asymmetries in performance of mean velocity throwing (P=0.003; ES=-0.60) and peak velocity throwing (P=0.025; ES=-0.43). No significant differences were found between dominant and non-dominant side in any of the trunk rotator strength assessment conditions (P>0.05).

CONCLUSIONS

There is a large or very large correlation between the STRM and the RMBT in all its modalities. Differences in strength were found between sexes, with no significant differences between dominant and non-dominant sides.

Resistance Training Practices of Brazilian Olympic Sprint and Jump Coaches: Toward a Deeper Understanding of Their Choices and Insights (Part III)

In the final part of this three-article collection on the training strategies of Brazilian Olympic sprint and jump coaches, we provide a detailed description of the resistance training methods and exercises most commonly employed by these speed experts. Always with the objective of maximizing the sprint and jump capabilities of their athletes, these experienced coaches primarily utilize variable, eccentric, concentric, machine-based, isometric, complex, and isoinertial resistance training methods in their daily practices. Squats (in their different forms), Olympic weightlifting, ballistics, hip thrusts, lunges, calf raises, core exercises, leg curls, stiff-leg deadlifts, and leg extension are the most commonly prescribed exercises in their training programs, during both the preparatory and competitive periods. Therefore, the current manuscript comprehensively describes and examines these methods, with the additional aim of extrapolating their application to other sports, especially those where sprint speed is a key performance factor.

Strength Assessment of Trunk Rotator Muscles: A Multicenter Reliability Study

BACKGROUND

Trunk rotator strength plays an important role in sports performance and health. A reliable method to assess these muscles with functional electromechanical dynamometer has not been described. Therefore, the objectives of this paper were (I) to explore the reliability of different strength variables collected in isokinetic and isometric conditions during two trunk rotator exercises, and (II) to determine the relationship of isometric and dynamic strength variables collected in the same exercise.

METHODS

A repeated measures design was performed to evaluate the reliability of the horizontal cable woodchop (HCW) and low cable woodchop (LCW) exercises. Reliability was assessed using t-tests of paired samples for the effect size, the standard error of measurement, the coefficient of variation (CV) and the intraclass correlation coefficient (ICC). The Pearson's (r) correlation coefficient was used to explore the association between isometric and isokinetic tests.

RESULTS

HCW exercise is more reliable than LCW exercise in assessing trunk rotator muscles. The strength manifestation that should be used is the average strength, and the most reliable evaluation was the HCW at 0.40 m·s-1 concentric (ICC = 0.89; CV = 10.21%) and eccentric (ICC = 0.85; CV = 9.33%) contraction and the dynamic condition that most correlated with the isometric was LWC at 0.50 m·s-1 (r = 0.83; p < 0.01).

CONCLUSION

HCW is a reliable exercise to measure trunk rotator muscles.