Lower limb muscle activity during table tennis strokes

Lower limb muscle activity during first and second tennis serves: a comparison of three surface electromyography normalisation methods

We assessed lower limb muscle activity during the execution of first and second tennis serves, exploring whether the extent of these differences is influenced by the chosen method for normalising surface electromyography (EMG) data. Ten male competitive tennis players first completed three rounds of maximal isometric voluntary contractions (MVC) of knee extensors and plantar flexors for the left (front) and right (back) leg separately, and three squat jumps. Afterward, they executed ten first and ten-second serves. Surface EMG activity of four lower limb muscles (vastus lateralis, rectus femoris, gastrocnemius lateralis, and soleus muscles) on each leg was recorded and normalised in three different ways: to MVC; to peak/maximal activity measured during squat jump; and to the actual serve. For the rectus femoris and soleus muscles of the left leg, and the gastrocnemius lateralis and soleus muscles of the right leg, EMG amplitude differed significantly between normalisation techniques (P ≤ 0.012). All muscles showed greater activity during the first serve, although this difference was only statistically significant for the right vastus lateralis muscle (P = 0.014). In conclusion, the EMG normalisation method selected may offer similar information when comparing first and second serve, at least for leg muscles studied here.

Lumbar and pelvis movement comparison between cross-court and long-line topspin forehand in table tennis: based on musculoskeletal model

Introduction: Cross-court and the long-line topspin forehand is the common and basic stroke skill in table tennis. The purpose of this study was to investigate the differences in lumbar and pelvis movements between cross-court and long-line topspin forehand strokes in table tennis based on musculoskeletal demands using OpenSim. Materials and Methods: The eight-camera Vicon system and Kistler force platform were used to measure kinematics and kinetics in the lumbar and pelvis movement of sixteen participants (Weight: 69.89 ± 1.58 kg; Height: 1.73 ± 0.03 m; Age: 22.89 ± 2.03 years; BMI: 23.45 ± 0.69 kg/m²; Experience: 8.33 ± 0.71 years) during cross-court and long-line topspin forehand play. The data was imputed into OpenSim providing the establishment of the Giat2392 musculoskeletal model for simulation. One-dimensional statistical parametric mapping and independent samples t-test was performed in MATLAB and SPSS to analyze the kinematics and kinetics. Results: The results show that the range of motion, peak moment, and maximum angle of the lumbar and pelvis movement in cross-court play were significantly higher than in the long-line stroke play. The moment of long-line in the sagittal and frontal plane was significantly higher than cross-court play in the early stroke phase. Conclusion: The lumbar and pelvis embody greater weight transfer and greater energy production mechanisms when players performed cross-court compared to long-line topspin forehand. Beginners could enhance their motor control strategies in forehand topspin skills and master this skill more easily based on the results of this study.

Lower Limb Biomechanics during the Topspin Forehand in Table Tennis: A Systemic Review

The aim of this study is to review the valuable lower limb biomechanical contribution to table tennis topspin forehand. Databases included Scopus, PubMed, and Web of science. In this case, 19 articles were selected for the systematic review. The mechanics of the plantar, lower limb joints kinematics and kinetics, muscle activity, and racket-joint relationship are described through gender, performance level, and footwork. The study found that the hip movement characteristics and the hip muscle group activity following a proximal-to-distal sequence strategy significantly contributed to the maximum acceleration of the racket. Optimizing the motion strategy of the ankle and plantar as well as the ankle muscle group activity is beneficial for the transmission of energy in the kinetic chain. Muscle groups around the ankle and subtalar joints are heavily activated during landing to maintain foot stability during the landing phase. Lower limb muscle development plays an important role in movement control and stability as well as sports injury prevention in table tennis footwork during the performance of the topspin forehand. Furthermore, physical development levels and anatomical differences (such as hip and lower trunk muscle strength differences), maybe the main reasons for gender differences observed during the topspin forehand. Systematically summarizing this valuable information can contribute to athletes’ and coaches’ knowledge to enhance topspin forehand performance and training regimes. We suggest that future research could consider the joint contact forces, ball movement, and ball-racket impact during a performance of topspin forehand.

Lower limb kinetic comparisons between the chasse step and one step footwork during stroke play in table tennis

Background

Biomechanical footwork research during table tennis performance has been the subject of much interest players and exercise scientists. The purpose of this study was to investigate the lower limb kinetic characteristics of the chasse step and one step footwork during stroke play using traditional discrete analysis and one-dimensional statistical parameter mapping.

Methods

Twelve national level 1 table tennis players (Height: 172 ± 3.80 cm, Weight: 69 ± 6.22 kg, Age: 22 ± 1.66 years, Experience: 11 ± 1.71 year) from Ningbo University volunteered to participate in the study. The kinetic data of the dominant leg during the chasse step and one step backward phase (BP) and forward phase (FP) was recorded by instrumented insole systems and a force platform. Paired sample T tests were used to analyze maximum plantar force, peak pressure of each plantar region, the force time integral and the pressure time integral. For SPM analysis, the plantar force time series curves were marked as a 100% process. A paired-samples T-test in MATLAB was used to analyze differences in plantar force.

Results

One step produced a greater plantar force than the chasse step during 6.92–11.22% BP (P = 0.039). The chasse step produced a greater plantar force than one step during 53.47–99.01% BP (P < 0.001). During the FP, the chasse step showed a greater plantar force than the one step in 21.06–84.06% (P < 0.001). The one step produced a higher maximum plantar force in the BP (P = 0.032) and a lower maximum plantar force in the FP (P = 0) compared with the chasse step. The one step produced greater peak pressure in the medial rearfoot (P = 0) , lateral rearfoot (P = 0) and lateral forefoot (P = 0.042) regions than the chasse step during BP. In FP, the chasse step showed a greater peak pressure in the Toe (P = 0) than the one step. The one step had a lower force time integral (P = 0) and greater pressure time integral (P = 0) than the chasse step in BP, and the chasse step produced a greater force time integral (P = 0) and pressure time integral (P = 0.001) than the one step in the FP.

Conclusion

The findings indicate that athletes can enhance plantarflexion function resulting in greater weight transfer, facilitating a greater momentum during the 21.06–84.06% of FP. This is in addition to reducing the load on the dominant leg during landing by utilizing a buffering strategy. Further to this, consideration is needed to enhance the cushioning capacity of the sole heel and the stiffness of the toe area.

Effects of Power and Ballistic Training on Table Tennis Players' Electromyography Changes

The aim of the present study was to analyze the effects of ballistic and power training on table tennis players' electromyography (EMG) changes. Thirty male table tennis players, who were able to perform top spin strikes properly, were randomly assigned to three groups: power training (PT; n = 10); ballistic training (BT; n = 10); and no training (CON = control group; n = 10). PT and BT were performed 3 times weekly for 8 weeks. Before and after training programs, a one-repetition maximum test (1RM) and the EMG activity of all the subjects' upper/lower body muscles while performing top spin strokes were analyzed. After training, significant interactions (group × time) were observed in increasing 1RM strength in upper/lower muscles (p < 0.05). However, neither training type had any significant effect on muscle EMG activity. These findings suggest that there should not necessarily be any significant change in the EMG signal after BT and PT despite the increase in muscle strength.

Creating a Scoring System with an Armband Wearable Device for Table Tennis Forehand Loop Training: Combined Use of the Principal Component Analysis and Artificial Neural Network

BACKGROUND

This study presents an intelligent table tennis e-training system based on a neural network (NN) model that recognizes data from sensors built into an armband device, with the component values (performances scores) estimated through principal component analysis (PCA).

METHODS

Six expert male table tennis players on the National Youth Team (mean age 17.8 ± 1.2 years) and seven novice male players (mean age 20.5 ± 1.5 years) with less than 1 year of experience were recruited into the study. Three-axis peak forearm angular velocity, acceleration, and eight-channel integrated electromyographic data were used to classify both player level and stroke phase. Data were preprocessed through PCA extraction from forehand loop signals. The model was trained using 160 datasets from five experts and five novices and validated using 48 new datasets from one expert and two novices.

RESULTS

The overall model's recognition accuracy was 89.84%, and its prediction accuracies for testing and new data were 93.75% and 85.42%, respectively. Principal components corresponding to the skills "explosive force of the forearm" and "wrist muscle control" were extracted, and their factor scores were standardized (0-100) to score the skills of the players. Assessment results indicated that expert scores generally fell between 60 and 100, whereas novice scores were less than 70.

CONCLUSION

The developed system can provide useful information to quantify expert-novice differences in fore-hand loop skills.

Benefits of Regular Table Tennis Practice in Body Composition and Physical Fitness Compared to Physically Active Children Aged 10-11 Years

The aim of this study was to identify the differences in body composition and physical fitness between children who played table tennis regularly during a two-year period compared to physically active children who were not engaged in a regular activity. Three hundred seventy-four children aged 10 to 11 years were divided into two groups: table tennis players (n = 109 boys and 73 girls) and physically active group (n = 88 boys and 104 girls). Anthropometric analysis included body mass index, skinfolds, perimeters and bone diameters. Somatotype and body composition were determined according to age-specific equations. Physical fitness assessment included hand grip dynamometry (strength), sit-and-reach test (range of movement) and maximal multistage 20 m shuttle run test (cardiovascular fitness). The result show that children who regularly played table tennis had greater bone development and superior physical fitness compared to those who were physically active but not engaged in a regular physical activity. This is the largest study to date presenting data about the potential of table tennis to benefit health in children. These results constitute an important first step in clarifying the effectiveness of table tennis as a health-promotion strategy to encourage children to undertake regular physical activity and limit sedentary behavior.

Biomechanics of Table Tennis: A Systematic Scoping Review of Playing Levels and Maneuvers

This present study aims to review the available evidence on the biomechanics of table-tennis strokes. Specifically, it summarized current trends, categorized research foci, and biomechanical outcomes regarding various movement maneuvers and playing levels. Databases included were Web of Science, Cochrane Library, Scopus, and PubMed. Twenty-nine articles were identified meeting the inclusion criteria. Most of these articles revealed how executing different maneuvers changed the parameters related to body postures and lines of movement, which included racket face angle, trunk rotation, knee, and elbow joints. It was found that there was a lack of studies that investigated backspin maneuvers, longline maneuvers, strikes against sidespin, and pen-hold players. Meanwhile, higher-level players were found to be able to better utilize the joint power of the shoulder and wrist joints through the full-body kinetic chain. They also increased plantar pressure excursion in the medial-lateral direction, but reduced in anterior-posterior direction to compromise between agility and dynamic stability. This review identified that most published articles investigating the biomechanics of table tennis reported findings comparing the differences among various playing levels and movement tasks (handwork or footwork), using ball/racket speed, joint kinematics/kinetics, electromyography, and plantar pressure distribution. Systematically summarizing these findings can help to improve training regimes in order to attain better table tennis performance.

Joint and plantar loading in table tennis topspin forehand with different footwork

Table tennis players often execute one-step, side-step or cross-step to move to an appropriate position for topspin forehand. However, to our knowledge, no studies have investigated the footwork effects on lower-limb kinetics and kinematics, which are related to playing performance and injury prevention. This study examined the ground reaction forces, joint kinetics and in-shoe plantar pressure distribution during topspin forehand with three typical footwork patterns. Fifteen male table tennis players performed cross-court topspin forehands in one-step, side-step and cross-step. Force plate, motion capturing, and instrumented insole systems were used to measure ground reaction force, joint moments and plantar pressure variables. One-way ANONA with repeated measures was performed to determine any significant differences between footwork. Results indicated that participants exhibited significantly higher ground reaction force loadings, knee flexion angle, knee moment, ankle inversion and moment during side-step and cross-step compared with one-step footwork condition (p < .01). Plantar pressure data indicated that the significantly higher peak pressure were observed in the total foot, toe, 1st, 2nd and 5th metatarsal regions during side-step and cross-step (p < .01). Additionally, cross-step had induced higher peak pressure in medial midfoot and heel regions than one-step and higher peak pressure in total and 1st metatarsal regions than side-step (p < .01). These results suggest that foot orthotic designs should consider the stronger emphasis on those high-pressured areas and that the differential joint and plantar loadings in side-step and cross-step may provide useful insights to injury mechanism and training protocol development.