Influence of Posture-Cuing Shirt on Tennis Serve Kinematics in Division III Tennis Players

Kinematics characteristics of key point of interest during tennis serve among tennis players: a systematic review and meta-analysis

The objective of this systematic review and meta-analysis was to provide an overview of kinematic parameters associated with key points of interest in the tennis serve. The research was conducted according to the PRISMA guideline without date restriction. Google scholar, Science Direct, PubMed/Medline, Mendeley, and Science.gov databases were scanned to find relevant studies. Only English peer-review original article focused on joint body angles at trophy position, racket low point and ball impact were retained. The review, quality appraisal, and data extraction from selected studies were performed independently by two reviewers. A meta-analysis was carried out on the most studied joint parameters. Among the 2,844 records identified, 27 articles were included. The wide variety of methods used required data homogenization for comparison purposes. Trunk inclination (25.0 ± 7.1°) and front knee flexion (64.5 ± 9.7°) were the most studied parameters for trophy position. Shoulder lateral rotation (130.1 ± 26.5°) was systematically evaluated for racket low point. At ball impact, shoulder elevation (110.7 ± 16.9°) and elbow flexion (30.1 ± 15.9°) were the most considered joint angles. The systematic review revealed that many kinematic parameters were not quantified at the various key points of interest. Knowledge of the kinematics is essential for understanding the gesture, implementing training methods, and improving the performance.

Kinematics of the Tennis Serve Using an Optoelectronic Motion Capture System: Are There Correlations between Joint Angles and Racket Velocity?

The serve is the most important stroke in tennis. It is a complex gesture consisting of numerous rotations with a wide amplitude, which are important to manage for performance. The aim of this study was to investigate whether correlations exist between joint kinematic parameters and racket velocity. A quantitative kinematics analysis of four ranked players (two boys and two girls) was carried out using an optoelectronic system composed of 10 cameras (150 Hz). Five flat serves per player were analyzed. Eighty-two markers were located across the 15 body segments and on the racket. A descriptive statistical analysis including a correlation analysis was carried out between joint angles and racket kinematic parameters (vertical position, velocity, and acceleration) during the cocking and acceleration phases. Ten very high (0.7 < r < 0.9) and three almost perfect (r > 0.9) correlations were found. Shoulder and hip axial rotations, knee flexion, and trunk extension were correlated linearly with racket vertical position and velocity during the cocking phase. For the acceleration phase, elbow flexion, trunk flexion/extension, and trunk axial rotation were linked to racket kinematics. Some of these parameters showed differences between slow and fast serves. These parameters, which are involved in transmitting ball velocity, are important to consider for tennis players and coaches in training programs, education, and performance enhancement.

Biophysical characterization of the tennis serve: A systematic scoping review with evidence gap map

OBJECTIVES

We aimed to assess the available evidence on the biophysics of the tennis serve, mapping the populations, interventions, contexts and other relevant information to highlight what is already known and to identify gaps in the literature.

DESIGN

Systematic scoping review with evidence gap map.

METHODS

The protocol was designed according to PRISMA 2020, Prisma-ScR guidelines and the Cochrane Handbook. The searches were conducted on July 20, 2022 and updated on April 1, 2023, in PubMed, Scopus and Web of Science (core collection). The risk of bias assessment was performed using the Cochranes method for nonrandomized studies (RoBANS) and a narrative synthesis of the main findings was performed and supplemented with an evidence gap map.

RESULTS

Most trials were found on serve kinematics and kinetics (95 %), analyzing only flat serves (84 and 72 %, respectively). Few trials focused on physiology (20 %; e.g. biomarkers), under-19, left or both-handed, female and intermediate beginner or starter players (29, 17, 8 and 7 %, respectively). We found a preponderance of low and unclear risk of bias (63 and 31 %, respectively) and only 7 % high, particularly, on the assessment of confounding variables.

CONCLUSIONS

The current scoping review reveals a few trials on physiological rather than biomechanical variables, as well as the absence of the kick and slice serve, foot-back and foot-up serve, and left-handed, female, and young player analyses. We did not find systematic mistakes or limitations in the design, conduct, or analysis that would distort the results, since only 7 % presented a high risk of bias.

Effect of a Posture-Cueing Shirt on Sitting Posture During a Functional Task in Healthy Participants: A Randomized Cross-Over Study

OBJECTIVES

The purpose of this study was to investigate the effect of a posture-cueing shirt on sitting posture during a functional task.

METHODS

Thirty healthy male participants were seated at a standardized workstation while completing 3 laptop writing tasks of 15-minute duration wearing either a posture-cueing shirt, a compression shirt, or no shirt. Posture was assessed based on photos taken at minutes 1 and 15 into the writing task from which the head and shoulder angles were measured and extracted for analysis. After each task, participants rated any potential pain they felt during the task on an 11-point numeric rating scale (NRS).

RESULTS

The results showed that none of the shirts significantly affected the head or shoulder angles at any time point. Participants reported lower pain levels after using the posture-cueing shirt (NRS 0 [0-1]) compared with no shirt (NRS 1 [0-2]; P = .012). No significant difference in pain levels was observed between shirts.

CONCLUSION

Although posture did not change in any conditions for these healthy male subjects, the posture-cueing shirt resulted in a lower pain intensity compared with no shirt but not with a compression shirt. Although a significant difference was found for pain intensity favoring the posture-cueing shirt, this difference was negligible, and thus its value to reduce pain or improve posture in healthy subjects remains in question.

Technical analysis of adaptive neuron fuzzy intelligent system in tennis serve

Serving is the most important hitting technique in tennis, and a good service receiving can instantly reverse the active and passive relationship between serve and receive on the tennis court, and control the rhythm of the court. The purpose of this study is to use an adaptive neuron fuzzy intelligent system to analyze some techniques of tennis serve. In this study, eight male players from the school tennis team were selected as the experimental subjects, whose sports level was above the national tennis level II. Ten weeks before the simulation test, the training time and frequency of 8 subjects were the same. In other words, 5 times a week, 2.5 hours±0.5 hours. The work engineering of adaptive fuzzy system firstly, in the off-line modeling stage, the adaptive fuzzy system uses the rule self splitting technology to generate the initial fuzzy rules, and uses the improved adaptive neural network algorithm to optimize the calculation; then according to the error between the system input and the predicted output, the independent variable is adjusted and replaced; at the same time, the adaptive fuzzy system is further used for calculation In the process of tennis serving, the nonlinear control variables are obtained online and applied to the fuzzy system for control. Next, in the experiment, the system was used to record the body’s movement and service scores during service. The experimental results show that during the service process, the maximum trunk torsion amplitude can reach 48.26 ° and the minimum is only 5.41 ° and the service score accounts for 81.41% and 80.47% of the total scores of the two sections respectively. This shows that the fuzzy system in this study can effectively analyze the service posture and score of athletes. It is concluded that the accurate calculation and analysis of tennis serve by adaptive neuron intelligent fuzzy system in this study is conducive to improve the tennis serviceability and competition performance of players. This research has made a certain contribution to the intellectualization of sports.

The use of posture-correcting shirts for managing musculoskeletal pain is not supported by current evidence - a scoping review of the literature

BACKGROUND AND AIMS

The concept of bad posture being a dominant driver of pain is commonly held belief in the society. This may explain the significant attention supportive clothing such as posture-correcting shirts has recently gained in Scandinavia and the USA. The aim of this scoping review was to present an overview and synthesis of the available evidence for the use of posture-correcting shirts aimed at reducing pain or postural discomfort and optimising function/posture.

METHODS

A systematic search was conducted for literature investigating the effect of posture-correcting shirts on musculoskeletal pain or function. PubMed, Embase, CINAHL, PEDro and the Cochrane Library were searched for relevant literature. Results of the searches were evaluated by two independent reviewers in three separate steps based on title, abstract and full text. For data synthesis, the population, intervention, comparator and outcome were extracted. The quality of the literature was evaluated using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies and the risk of bias was assessed using the Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I) assessment tool or the RoB 2.0 tool for individually randomized, parallel group trials. The overall confidence in the literature was determined using the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

A total of 136 articles were identified and six of these were included in the review. These studies were heterogeneous with regards to aims, outcomes and methods, presenting contrasting results. The overall findings were that posture-correcting shirts change posture and subjectively have a positive effect on discomfort, energy levels and productivity. The quality of the included literature was poor to fair with only one study being of good quality. The risk of bias was serious or critical for the included studies. Overall, this resulted in very low confidence in available evidence. An important limitation of all studies was that they were conducted in pain-free individuals.

CONCLUSIONS

The contrasting findings and the low quality of current literature, questions the intended effect of posture-correcting shirts and whether the changes it creates are in fact useful for clinical practice. Moreover, the findings are contrasted by the available evidence regarding posture and pain with a particular focus on whether this management strategy may have a detrimental effect on people living with musculoskeletal pain. A major limitation to the existing literature on the effect of posture-correcting shirts is that no studies have investigated their effect in clinical populations.

IMPLICATIONS

Based on the available literature and the major limitation of no studies investigating clinical populations, there is no good quality evidence to support recommendation of posture-correcting shirts as a management strategy for musculoskeletal pain. Promotion of this product may reinforce the inaccurate and unhelpful message that poor posture leads to pain. The efficacy of such garments should be tested in clinical populations and not only in pain-free individuals, to assess whether there is any meaningful benefit of this management approach. Until then, the use of posture-correcting shirts for musculoskeletal pain is not supported by current evidence.