Pitching mechanics and performance of adult baseball pitchers: A systematic review and meta-analysis for normative data.

OBJECTIVES: The aim of this systematic review was to critically review and synthesise the findings from primary studies on pitching mechanics and performance of healthy adult baseball pitchers. DESIGN: Systematic review with meta-analysis. METHODS: Eight English- and Japanese-language databases were systematically searched from inception to 22nd July 2022. RESULTS: In total, 29 descriptive biomechanical studies were included. Overall study quality was moderate. In subgroup analyses, professional pitchers showed significantly higher stride length, peak shoulder internal rotation velocity, peak shoulder proximal force and ball velocity compared to collegiate pitchers. Conversely, collegiate pitchers were found to have significantly higher peak pelvis rotation velocity. CONCLUSIONS: Available normative data suggested potentially heterogeneous pitching mechanics and performance between professional and collegiate pitchers. However, the findings in this review should be interpreted cautiously. Since statistical heterogeneity was significant within most data sets, more detailed subgroup analyses are required. Additionally, more high-quality studies utilising measurement systems with established reliability are required to obtain accurate data in baseball pitching mechanics and performance.

Risk Factors of Shoulder and Elbow Injuries in Baseball: A Scoping Review of 3 Types of Evidence.

BACKGROUND: Shoulder and elbow overuse injuries are the most common problems in baseball players. No scoping review has compared the findings from different types of evidence. PURPOSE: To map the broad evidence from 3 types of evidence (epidemiological, biomechanical, and narrative) on potential risk factors for shoulder and elbow injuries in baseball and identify gaps in the existing literature to guide future research. STUDY DESIGN: Scoping review. METHODS: Eight electronic databases were searched from inception to May 14, 2020. Any peer-reviewed papers that investigated or discussed potential risk factors for shoulder and elbow injuries in baseball were included. RESULTS: A total of 302 studies (107 epidemiological studies, 85 biomechanical studies, and 110 narrative reviews) were included. Risk factors were categorized into 9 domains: sports profiles, physical characteristics/functions, pitching mechanics, performance, behavioral, psychosocial, biological and developmental, injury/sports profiles, and environmental factors. Studies were consistent in supporting limited shoulder range of motion (ROM) and player positions (pitchers or catchers) as risk factors for shoulder injuries. For elbow injuries, the majority of the included studies suggested that being pitchers or catchers and working with higher ball velocity can be risk factors. CONCLUSION: Findings were consistent in some risk factors, such as limited shoulder ROM and positions. However, findings were inconsistent or limited for most factors, and substantial research gaps were identified. Research assessing those factors with inconsistent or limited evidence in the current literature were recognized to be priorities for future studies.

IS PRE-PERFORMANCE MASSAGE EFFECTIVE TO IMPROVE MAXIMAL MUSCLE STRENGTH AND FUNCTIONAL PERFORMANCE? A SYSTEMATIC REVIEW.

BACKGROUND: Although pre-performance massage is frequently used in sports settings, the evidence regarding its effects on muscle strength and functional performance is equivocal.Purpose: The purpose of this systematic review was to synthesize the findings of randomized controlled trials (RCTs) investigating the effects of pre-performance massage on strength and functional performance.Study Design: Systematic review with qualitative analysis. METHODS: Eight electronic databases were searched from inception until June 2017. Methodological quality of included studies were assessed using Physiotherapy Evidence Database scale. Data was synthesized qualitatively. RESULTS: Nine crossover RCTs with varied methodological qualities met inclusion criteria. Six out of nine studies had low quality, while two were of moderate-quality and one was high-quality. Following the descriptive analysis using within-group effect sizes of interventions used in included studies, no evidence was found to support the use of any kind of massage interventions (passive manual massage or self-massage) to enhance maximal strength, sprint or jump performances of young healthy subjects. In fact, there appears to be limited evidence which implies the negative effects of passive manual massage. In particular, longer-duration (> 9 minutes) of massage interventions tended to result in negative effects on lower-limb maximal strength, sprint performance and jump height. CONCLUSION: In conclusion, the use of longer-duration pre-performance massage cannot be recommended for enhancing young athletes' strength and performance in sprint and vertical jump. More high-quality RCTs are necessary to examine overall effects of pre-performance massage on athletes' performance. LEVEL OF EVIDENCE: 1a.

Effectiveness of Stretching on Posterior Shoulder Tightness and Glenohumeral Internal-Rotation Deficit: A Systematic Review of Randomized Controlled Trials.

CONTEXT: Posterior shoulder tightness (PST) and glenohumeral internal-rotation deficit (GIRD) can contribute to shoulder pain suffered by athletes engaged in overhead sporting activities. Stretching is a common intervention to resolve PST and GIRD, but it has weak evidence of effectiveness to date. OBJECTIVE: This systematic review aimed to collect and synthesize effectiveness data from English- and Japanese-language randomized controlled trials (RCTs) investigating stretching interventions for PST and GIRD. EVIDENCE ACQUISITION: 7 English databases and 3 Japanese databases were searched from inception until December 5, 2015. Only English- and Japanese-language RCTs were considered. Risk of bias in the included studies was assessed using the Physiotherapy Evidence Database scale. Data were synthesized qualitatively. EVIDENCE SYNTHESIS: Eight English-language and 2 Japanese-language papers of low to high quality were included. There was moderate evidence for positive immediate and short-term effects of cross-body stretch on PST and GIRD in asymptomatic young subjects. Moderate evidence was found to suggest that active sleeper stretch might not be more effective than no intervention to improve PST and GIRD in the short term. CONCLUSIONS: Cross-body stretch can be effective to improve PST and GIRD in asymptomatic young subjects immediately or in the short term. Further study with methodological rigor is necessary to investigate the long-term effectiveness of stretching interventions on PST and GIRD in symptomatic patients.

The effectiveness of braces and orthoses for patients with knee osteoarthritis: A systematic review of Japanese-language randomised controlled trials.

BACKGROUND: Knee osteoarthritis is common. The evidence regarding the effectiveness of braces and orthoses for patients with knee osteoarthritis is inconclusive according to English-language literature. English-language reviews to date have not included Japanese-language studies. OBJECTIVES: This study aimed to collect and synthesise Japanese-language randomised controlled trials investigating the effectiveness of braces and orthoses for patients with knee osteoarthritis. STUDY DESIGN: Systematic review. METHODS: Eight databases were systematically searched from inception to 29 July 2015. Only Japanese-language randomised controlled trials were included. Risk of bias was assessed using Physiotherapy Evidence Database scale. A meta-analysis was not appropriate due to the heterogeneity in the included studies. RESULTS: Seven randomised controlled trials with low to high risks of bias were included. Six of seven included studies were conducted by the same author group. Limited evidence supported the positive effects of short-lever elastic knee braces to improve pain and functional disability in specific outcomes. No evidence was found to support the use of foot orthoses, such as laterally wedged insoles, medial arch support and metatarsal arch pad. CONCLUSION: Our systematic review found no conclusive evidence about the effectiveness of any braces and orthoses for patients with medial knee osteoarthritis. Future Japanese-language studies should address methodological flaws exposed in this review and strengthen the international evidence base. Clinical relevance This is the first systematic review of Japanese-language randomised controlled trials investigating orthoses for patients with knee osteoarthritis. Clinicians can consider the use of short-lever elastic knee braces to improve specifically pain on squat or walking. Evidence found in this review does not support the use of foot orthoses.

Acute effects of stretching on maximal muscle strength and functional performance: A systematic review of Japanese-language randomised controlled trials.

BACKGROUND: There is no consensus in the English-language literature regarding the best types or dosages of stretching to maximise muscle strength and functional performance. It is possible that primary research published in non-English languages provides different insights, and could add to the body of international knowledge. PURPOSE: This systematic review aimed to identify and evaluate Japanese-language randomised controlled trials (RCTs) investigating acute effects of stretching on maximal strength and functional performance. METHODS: Three Japanese databases and five English databases were searched from inception to 24 March 2015. Only Japanese-language RCTs examining acute effects of stretching on maximal strength and/or functional performance were included. Risk of bias in included studies was assessed using Physiotherapy Evidence Database scale. GRADE (Grading of Recommendation Assessment, Development and Evaluation) approach was applied to evaluate the quality of evidence. Descriptive synthesis was attempted. RESULTS: Seven RCTs with variable methodological quality were included. No two studies were the same, thus meta-analysis was not possible. Descriptively, because of heterogeneity of interventions and outcome measures, it was not possible to identify consensus on the benefits of stretching. GRADE approach indicated low to very low quality evidence for this topic. CONCLUSION: This review of Japanese-language RCTs provided no additional information to strengthen or challenge the current English-language evidence base on acute effects of stretching on maximal strength and performance. Future Japanese-language studies should address methodological flaws exposed in this review and incorporate functional outcome measures to strengthen the international evidence base.