Acta Kinesiologica

Tennis performance priorities for all-court player using the Analytic Hierarchy Process method

Mladen Hraste — 2024-07-05

Purpose: Above all, a wealth of research into the game of tennis has failed to provide an answer to the question of how to
measure the overall performance of a top tennis player under competitive conditions. The aim of this study was to investigate
the priorities for all-court tennis players on offence and defence.
Methods: The relative importance coefficients related to the style of all-court tennis players were determined for eighteen
criteria for evaluating overall performance based on the expertise conducted by seven tennis experts. In this study, the
priorities for “all-court” style were analysed using the Analytic Hierarchy Process method. From each given matrix, the
vectors of importance coefficients defined by each of the experts were calculated using the geometric mean method and
used to form a matrix of importance coefficients for an all-court player. The vectors of the arithmetic mean and standard
deviations were calculated.
Results: The top of the defensive hierarchical structure indicates that the quality of movement/defensive tasks and the
quality of the first serve-return have a high importance; the quality of performance in long rallies has a medium to high
importance. The top of the offensive hierarchy structure indicates that playing with multiple styles and the quality of the
first serve have a high importance; the quality of taking the initiative in rallies and the quality of the offensive forehand have
a medium to high importance.
Conclusions: The results of this study can be used by coaches to select the optimal technical and tactical solutions.

IMU- and TENS-based work and power calculation methods in hip flexion resistance training

Dobrochna Fryc — 2024-07-05

Purpose: The study is the first part of a series presenting the primary results of multijoint hip flexion resistance training
biomechanical investigation. The series evaluates the exercise in the context of possible implementation in hip flexors
shortening and hypertension. The described exercise was designed to use muscle hypertrophy as a solution for pelvis
stabilizing muscles’ imbalance. This study aims to evaluate the work performed and power generated during hip flexion
resistance training using two established methods and investigate the potential of IMU sensors as a cost-effective tool for
measuring individual performance and progress in non-laboratory settings.
Methods: The study was conducted with the use of training equipment constructed according to patent P.435615 allowing
for the application of downward directed force to feet while performing hip flexion. Thirteen healthy students (7 females
and 6 males, body-height 176.00 ± 12.54 cm, body-mass 73.69 ± 18.08 kg, age: 21.77 ± 1.09 years) took part in the training
session using three different additional loads (0, 2.5, and 5 kg). Techniques applied in the study included optical kinematics
capture, strain gauges, and inertial sensors.
Results: The average work of (TENS/IMU) were 56.57 ± 12.00 / 58.13 ± 13.07 - 76.54 ± 13.88 / 74.40 ± 13.93 J and an
average power of 23.22 ± 6.43 / 23.65 ± 7.12 - 31.51 ± 9.42 / 31.62 ± 10.60 W were calculated for the additional load of 0 kg
and 5 kg respectively. The correlation between values calculated with two tested methods was high both for power (R= .85
P< .001) and work (R= .86 P< .001).
Conclusions: Referenced data indicate a good correlation between the two methods but prove the need for further
improvement of IMU-based method precision. It also allowed to determine a potential baseline of 15kg additional load for
1RM tests maximal value.

A six-month Kinesiological intervention following a patellar tendon reconstruction in a soccer player: A focus on exercise prescription and assessment for a safe return to sport participation

Stefano Marinelli — 2024-07-22

Purpose: This study aimed to analyze a 6-month Kinesiological intervention after patellar tendon reconstruction. The kinetics, kinematics, and neuromuscular differences between operated limb (OL) and non-operated limb (N-OL) were assessed over time in a soccer player.

Methods:The assessment was performed at three (T0) and nine months after the reconstruction (T1) and included: the range of motion (ROM), gait analysis through angle-angle diagrams, postural control, neuromuscular assessment during whole-body vibration (WBV), and unilateral-bilateral maximal voluntary isometric contractions (MVICs) synchronized with surface electromyography (sEMG).

Results: The angle-angle diagrams at T1 showed an increase in the area and perimeter in the N-OL and OL, particularly for the area and perimeter of knee-ankle diagram in OL. Also, the postural control at T1, showed an increase in the different conditions. The sEMG_RMS recorded during WBV revealed a significant changed in the neuromuscular patterns in the OL at T1; the sEMG increase in the vastus lateralis (VL) and lateral gastrocnemius (LG) activities with a concomitant decrease in the biceps femoris (BF) and tibialis anterior (TA). The peak of force and the rate of force development during MVICs showed a slight difference between OL and N-OL at T1. Also, the sEMG_RMS activities synchronized with MVICs showed a slight difference between the OL and N-OL in the extensors (VL, VM, and RF) and flexors (BF) muscles at T1.

Conclusions: The kinetic, kinematic, and neuromuscular variables have revealed improvements in the measurements performed at T1 compared with T0. A 6-month individualized Kinesiological intervention, following a patellar tendon reconstruction, re-establishes the neuromuscular patterns in the OL. These results provide a guideline to Kinesiologist in the management of the functional recovery following patellar tendon reconstruction.

Sleep, activity, and cognition: An analysis of academic impact on university students.

Monoem Haddad — 2024-06-13

Purpose: This study aimed to construct and assess a theoretical framework to elucidate the interrelationships between
sleep, physical activity, cognitive function, and academic outcomes in Qatari university students.
Methods: A study involving 44 students (age: 23.59 years ± 4.34) was conducted. The variables included “grade” (academic
performance), rapid visual information processing (RVIP), sleeping efficiency (SE), and average weekly steps (WS). Changes
in RVIP, SE, and WS over six weeks (two weeks before, during, and after exams) were analyzed using the Friedman test.
Bivariate Spearman’s correlations and mediation and moderation analyses were performed.
Results: The Friedman test confirmed significant variations in WS over the study period, indicating fluctuating physical
activity levels. A negative correlation was observed between age and physical activity, indicating decreased physical activity
in older students. A positive correlation was observed between academic performance and physical activity, suggesting a
beneficial impact of physical activity on academic outcomes. There was a significant indirect effect of physical activity on
academic performance via cognitive functioning, highlighting cognitive mediation.
Conclusions: These findings underscore the role of physical activity in enhancing academic performance, potentially through
cognitive advantages. This study establishes positive correlations between physical activity, academic performance, among
university students.

The Effects of Long-Term Interval Whole-Body Electrical Muscle Stimulation Physical Training Program on Body Composition and Subjective Pain Experience for Patient after Frozen Shoulder Diagnosis – A Single Case Study.

Julia Ciazynska — 2024-07-17

Purpose: This research aims to present the effects of a long-term interval whole-body electrical muscle stimulation (WB-EMS) training program on body composition and subjective pain experience for the patient after right shoulder adhesive capsulitis, known as a frozen shoulder. A 71-day program was designed for the patient two years after the frozen shoulder diagnosis and 6 months after finishing the postoperative rehabilitation phase.

Methods: A WB-EMS trainer supervised a subject as he worked out, following a detailed interval program displayed on a projector screen. The subject exercised by imitating the movements shown in a previously recorded video, while the trainer carefully observed the subject. All measurements and exercises performed based on programmed training were made in the laboratory with access to appropriate equipment.

Results: Body weight fluctuated during the training program. Comparing day 0 (before training) and day 71, an upward trend was observed for muscle mass and segmental body composition data for lean mass. A downward trend was observed for fat and segmental body composition data for fat mass. Body circumference data decreased for the hip, waist, and thigh. Body circumference data increased for the arm, calf, and chest. Our results indicated that combining WB-EMS with interval training can reduce fat (especially hip and waist area) and obtain gain mass, especially muscle mass.

Conclusions: The WB-EMS interval training program was a joint-shoulder-friendly form of physical exercise during which the patient reported no pain. The subject achieved the training goal: reducing fat mass and gaining muscle mass. Because of the study's controlled environment, this training could likely be adapted for successful home use with careful attention to detail, especially having the trainer’s guidance readily accessible.

The Technical and tactical actions in different styles of play in table tennis

Jerzy Grycan — 2024-07-02

Purpose: The aim of this work was to identify the combinations and strokes that players representing different styles of play
used most often to score, and to identify the differences between them.
Methods: A total of 146 games and 6565 winning actions of 7 champions, table tennis players representing different playing
styles were analyzed. The study used the modified Wu Huanqin game analysis method. It consists of complex observing
the game, counting the winning actions of a given player, sorting and identifying them, depending on the accuracy of the
observation. Three levels are included, with increasing detail in assessing players' actions. For all variables, percentage win
rates were calculated. Comparative analyses were performed. Due to the specificity of the database, chi square tests and
fraction tests were used.
Results: The most important differences between analyzed players were identified, which are the basis for classifying them
into different playing styles. These differences, as shown in the work, relate to tactical actions in different phases of the
game: service actions, returns or in the so-called stalemate phase. They are related to the use of different strokes and their
combinations to score points by players of different styles of play.
Conclusions: The research carried out made it possible to identify the most important strokes and their combinations with
which table tennis players score points and to identify differences between the playing styles. The results obtained in the
work can be valuable information for coaches and players, regarding the possibility of applying effective tactical actions
in the game, the direction of development of a particular style, or even, as a consequence, the possibility of taking specific
actions in the game against specific styles.

Evaluating the Impact of Active and Passive Recovery Strategies and Citrulline-Malate Supplementation in Wrestling: Do the Results Add Up?

Rahmat Ali Jafari — 2024-08-08

Purpose: This research aimed to investigate the impact of active and passive recovery strategies as well as Citrulline-Malate (CM) supplementation, on the performance and biomarkers, i.e., hypoxanthine and hypoxanthine-guanine phosphoribosyl transferase (HGPRT) of young trained wrestlers during the first day of a simulated Free-Style wrestling tournament.

Methods: A total of 12 professional freestyle wrestlers (aged: 19.2 ± 1.0 years) participated in the study. In a counterbalanced crossover design, twelve wrestlers ingested either a placebo or CM (8g) one hour before the initiation of the tournament. They then completed four consecutive simulated wrestling standard performance tests, each consisting of 6-minute wrestling simulations followed by a 30-minute recovery period, alternating between active and passive recovery.

Results: The results showed no significant effects of active versus passive recovery or CM supplementation versus placebo for various performance tests and biomarkers in trained wrestlers across multiple wrestling simulations. However, significant differences were observed in the active vs. passive recovery group for the HGPRT biomarker, burpee agility test, and RPE in the third simulated wrestling session. Other tests, such as hand grip strength, back-leg-chest, and Wrestling-Specific Performance Tests, did not show significant differences among the groups.

Conclusions: The findings revealed that there were no significant differences in performance tests or biomarkers between active and passive recovery strategies. Similarly, CM supplementation and placebo groups have not been equally effective in all events, during the simulated wrestling conducted on trained wrestlers. Individual responses to these strategies may vary among trained wrestlers and the recovery requirements can also differ between different events.

The interplay of normative, descriptive, and prescriptive discourses in shaping student teacher development: an analysis of physical education inspection reports

Chamseddine Guinoubi — 2024-08-08

ABSTRACT

Objectives: This study aimed to analyze physical education inspection discourse for insights into mentoring practices and teaching quality improvement. Examining reports provided perspective into normative, descriptive, and prescriptive evaluation aspects shaping student teacher development. Methods: The study involved 29 Tunisian inspectors of student teachers at the High Institute of Sport and Physical Education during the Fall 2022 academic term. In total, 117 pedagogical reports were obtained confidentially for discourse analysis. The analysis focuses on three types of discourse that may be present in the inspection reports: normative, descriptive, and prescriptive. The objective is to extract the most frequently used words and verbs by inspectors and to quantify the frequency of terms related to these three dimensions. Results: Analysis of verb and word frequencies within different discourse types revealed a significant association (χ² test, P=.0013, Cramer's V=.17, moderate effect size). Pedagogical inspectors predominantly employed normative language, with 78.1% of words and 62.7% of verbs falling into this category. This dominance suggests a focus on guiding, advising, and encouraging teachers through references to specific standards and practices. Notably, verbs like "guide" and "suggest" (14% and 12% frequency, respectively) were prevalent, highlighting a collaborative approach over direct imposition. Conclusion: This study challenges the singular focus on discourse modalities in inspector reports, revealing a multifaceted discourse ecosystem. While normative language sets standards and benchmarks, descriptive language captures classroom realities, and prescriptive language offers targeted guidance. This interplay fosters critical reflection, professional autonomy, and continuous improvement in student teachers. Inspectors, therefore, emerge as more than evaluators; they are facilitators.

The impact of a single “Body technique vitality protocol” treatment on vitality restoration: a randomized trial in urban women

Lovro — 2024-08-08

Purpose: The main purpose of the study was to investigate the efficiency and factorial validity of a newly developed vitality
questionnaire (AMRJ) in women.
Methods: In this randomized trial over six weeks, 161 women were randomly included. Each category of age represents one
period of life as follows: 17.5 years (adolescence), 30 years (menstruation and sexual activity), 45 years (perimenopause)
and 60 years (menopause). Opposed to subjective vitality status questionnaire (SVS), the AMRJ was designed to understand
one's personal perception of posture, body tissue, breathing, self-perception of health, pain and quality of life.
Results: For the AMJR, the two-factor solution explained 64% of variance among items, and all items loaded highly with their
underlying factors (all λ > .55). A large effect size (d= - .89) was observed for 17.5-year-olds, and a medium effect size (d=
- .50) was observed for 60-year-olds. Furthermore, current vitality ratings from the AMJR questionnaire were significantly
larger as well after the intervention, but the interpretation of the significant interaction terms goes in another direction. In
AMJR, the effects of the intervention increased with the participant’s age. The intervention effect had a medium effect size
for 17.5-year-olds (d= .67), and a large effect size (d= - .92) for 60-year-olds.
Conclusions: The AMJR questionnaire brings a new perspective on self-measured vitality and is published for the first time
with the affiliated presentation of validity. It shows current and potential vitality associated with the physical domain. Potential
point as a concrete individual fact brings objective goals and important motivational stimulus for vitality improvements.

Takes Two to Tango: Digital Twins and AI Revolutionize Sports Science and Medicine

Hadi Nobari — 2024-07-11

Purpose: Technological advancements are transforming the field of sports science and medicine, leading to a new era of performance improvement and injury prevention. Digital twins and artificial intelligence (AI) are at the forefront of these innovations, working together to redefine athletic training and monitoring. This editorial offers a comprehensive overview of the integration of digital twins and AI in sports science, with a focus on their potential applications, challenges, and future developments. By utilizing sensor data, AI algorithms, and biometrics, digital twins create virtual replicas of athletes, enabling precise performance monitoring and personalized training programs.

Conclusions: AI analysis of large datasets helps in predicting and preventing injuries, while also improving communication among stakeholders. Despite the promises, challenges such as privacy concerns and data accuracy need to be addressed. Future advancements will concentrate on sensor accuracy, AI algorithm refinement, and broader applications. The editorial highlights exciting research opportunities, including predictive injury models, real-time performance monitoring, and longitudinal health studies. Ultimately, the collaboration between digital twins and AI represents a paradigm shift in sports science, with the potential to revolutionize athlete well-being and performance optimization.