Gender and Leg-dominance Differences in Shoe Properties and Foot Injuries in Badminton

Background: While the roles of injury prevention and performance enhancement have increasingly been investigated for badminton footwear, there is a lack of research on gender-specific badminton footwear. The purpose of this study was to examine the gender differences in footwear demands and foot injuries in badminton. Methods: A supervised questionnaire survey of 326 recreational badminton players was collected. The questionnaire was divided into four sections enquiring about the characteristics of (1) participant profiles, (2) importance of shoe properties (3) shoe complaints. (4) and pain or discomfort in different foot regions. The Mann-Whitney U test and Wilcoxon Signed Ranks test were performed to determine the differences between genders and the differences between leg dominance, respectively. The significance level was set at 0.05.Results: Both males and females rated shoe fit as the most important features, followed by overall comfort, and injury protection. Females considered forefoot cushioning, comfort, breathability and color as the more important compared with other properties, which showed distinct pattern differences from males. The shoe problem results indicated that plantar pain of the non-dominant foot was considered the most commonly reported footwear problem by both males and females. The problem of excessive arch-support on the dominant and non-dominant sides of male participants was significantly higher than females (p < 0.05). Occasional pain or frequent pain were mainly distributed in the forefoot, followed by the rearfoot and midfoot regions.Conclusion: There were small differences in footwear demand between the dominant and non-dominant sides, but several differences existed between females and males. The results from gender differences suggested that female specific shoes prefer a specific better fit, rather than a modified version of male shoes. In the future, the design of badminton shoes should consider footwear demands and foot discomfort profiles in respective male and female badminton players.

Leg Dominance and OSB12 Kick Start Performance in Young Competitive Swimmers

The purpose of this study was to examine differences in starting and kick-plate positions, pointing to an effect on kick-start performance with the dominant and non-dominant feet placed on the front edge of the OSB12 starting block. The sample included 20 female competitive swimmers whose average age was 16.1 ± 0.6 years. To assess swimmers’ lower body explosive strength and determine leg dominance, a triple hop distance test was administered. We determined the swimmers’ preferred starting position on a starting block in terms of the kick-plate setting and body position on the starting block. The results of our study demonstrate the importance of leg dominance and positioning on the OSB12 starting block. After the preferred starting position was determined, the optimal position for the kick start was selected. When the dominant leg was placed on the front edge of the starting block (p < 0.05; Cohen’s d—large effect), swimmers produced shorter block times and times to 2 and 5 m. For most of the tested swimmers, the optimal basic position on the starting block included neutral- and rear-weighted positions with the kick plate set to positions 3–4 and the right leg placed on the front edge of the OSB12 starting block.

The effects of leg preference and leg dominance on static and dynamic balance performance in highly-trained tennis players

In this study, 90 (51 males, 39 females) tennis players performed single-leg quiet stance and single-leg landing tasks. For the static standing task, center-of pressure (CoP) velocities, amplitudes, frequency and area were calculated. For the landing tasks, time to stabilization as well as dynamic postural stability index were considered. The analysis of differences between the legs was done based on two methods for a priori determination of leg preference, one based on the preference of kicking a ball and one based on the preference for single-leg jumping. An additional analysis was done based on the leg dominance (determined post hoc), based on the observed performance of the tasks. In case of the classification based on kicking a ball, there was a statistically significantly lower CoP anterior-posterior velocity and anterior-posterior amplitude in static balance task (p ≤ 0.017; 0.17 ≤ d ≤ 0.28) for the preferred leg. The CoP frequency was higher in the preferred leg for both directions (p ≤ 0.002; 0.10 ≤ d ≤ 0.22). For the landing task, CoP medial-lateral time to stabilization was statistically significantly shorter for the preferred leg (0.28 ± 0.38 s) compared to the non-preferred leg (0.47 ± 0.60 s) (p = 0.012; d = 0.38). There were no differences between the legs for the landing task. Moreover, there were no differences between the legs when we used the preference based on jumping for either of the tasks (d ≤ 0.14). The differences between legs in terms of observed dominance were larger than the differences based on the preference, which stresses the need for clear distinction of limb preference and limb dominance in research and practice. Regarding the effect of leg preference, small differences in static balance may exist between the legs (when the preference is based on kicking a ball).

Influence of Weight Bearing Dorsiflexion (WBDF) on Ankle Injury History Among Semi-professional Recreational Basketball Players

Ankle injuries are one of the most common occurrences in the field of sports. Weight bearing dorsiflexion range can be an effecting factor in ankle injuries. Weight bearing lunge test is used to assess weight bearing dorsiflexion. By using this test as a standard testing protocol, it is possible to minimize development of further sport related ankle injuries. But this test for basketball players with ankle injuries has not been studied yet. The current study will aim to examine the weight bearing dorsiflexion of basketball players related to their gender, ankle injury history and leg dominance. A quasi-experimental design study was conducted. Thirty-four (34) participants were recruited and initially and two (2) were excluded. 18 participants were male and 14 were female basketball players in Colombo Blues and Kotelawala Defence University basketball teams. The average of age of the sample was 21.8 years. Demographic data, information about training time, injury history of the participants was obtained using an interview administered assessment form. The Weight Bearing Dorsiflexion was measured using digital inclinometer. Findings indicated that the weight bearing dorsiflexion range is smaller than that of males (p>0.05). There was a significant difference in weight bearing dorsiflexion and ankle injury history (p<0.01) among players. Significant differences were seen in influence in leg dominance to weight bearing dorsiflexion (p<0.05). This is the first study that is investigated weight bearing dorsiflexion among basketball players in Sri Lanka. No significant difference was found between gender and weight bearing dorsiflexion. A significant difference was determined between ankle injury history and weight bearing dorsiflexion. Furthermore, a significant difference was found in leg dominance and weight bearing dorsiflexion.

Investigation of Inter-Limb Symmetry in Knee Extensors Using Different Strength Outcome Measures

Muscle performance between contra-lateral knee extensors is most often assessed using maximal test for isometric/isokinetic torque evaluation. Recently, the rate of force development scaling factor (RFD-SF) has been used to evaluate neuromuscular capacity with a range of submaximal target peak torques, which could highlight other aspects of inter-limb (a)symmetry. The aim of our study was to investigate the differences, associations, and agreement between inter-limb symmetries of knee extensors using maximal torque (Tmax) rate of torque development (RTD), slope of the RFD-SF regression line (k), and theoretical peak of RTD (TPRTD). A total of 236 young, healthy athletes participated in the cross-sectional study. All participants performed unilateral knee extension (maximal voluntary contraction protocol and RFD-SF protocol) with both legs in the isometric knee dynamometer. Inter-limb symmetries were calculated for each outcome measure. Our results showed significant differences between all symmetry values (Tmax (91.7%), RTD (85.2%), k (94.2%), TPRTD (95.9%)). Significant strong correlations were found between symmetry values calculated from k and TPRTD (r = 0.88, p < 0.001), while weak correlation was found between Tmax and RTD (r = 0.17, p < 0.01. Fair agreement regarding leg dominance was found between Tmax and RTD values. Our results suggest that inter-limb (a)symmetries are metric- and task-specific.

Effects of shoe weight on landing impact and side-to-side asymmetry

Shoes of different weights affect proprioception. Drop jump (DJ) tasks are often used to explore the risks and mechanisms of lower limb injuries. Leg dominance mainly refers to differences between the dominant and nondominant legs. Eight males and eight females participated in this study. The weights of the shoes in this investigation were 255 g, 335 g, and 415 g, and the heights of the DJ were 30 cm, 40 cm, and 50 cm. The side-to-side asymmetry of the time of contact initiation for the 30DJ was greater than that of the 40DJ and 50DJ, and the asymmetry for shoes weighing 415 g and 355 g was greater than that for shoes weighing 255 g. When the drop height increased, the side-to-side asymmetry of the peak ground reaction force (PGRF). also increased. The ground contact time increased as the drop height increased to 50DJ. Higher drop heights caused greater side-to-side asymmetry of the PGRF. Heavier shoes caused the peak ground reaction force time (PGRFT) in the nondominant leg to appear earlier, reduced the jump height and affected the performance. Heavier shoes caused greater side-to-side asymmetry at the initial ground contact and at the ground contact time, affecting training effectiveness.

DEFINING LIMB DOMINANCE: A COMPARISON OF PERFORMANCE-BASED AND SELF-SELECTED MEASURES

Background: Limb dominance implies asymmetrical performance due to preferential strength or motor control within a single limb. While dominance may be easy to define and quantify within the upper extremity, there is currently no consensus as to whether limb dominance exists within the lower limbs, and if it does, how to best define it. While objective differences in limb performance would be the gold-standard for the identification of limb dominance, these methods may not be feasible within injured athletes. Several methods of identifying perceived limb dominance utilizing subjective reporting have been described; however, limb dominance may be task dependent and reports analyzing the correlation between objective and subjective performance are limited, particularly among adolescent athletes. Purpose: The purpose of this study was to test the agreement between performance-based and self-reported measures of limb dominance in three different single leg hopping tasks. Methods: These data were prospectively collected as part of a large cross-sectional study of healthy youth athletes aged 8-16 years-old. Self-selected limb dominance was determined by asking the following question: “Which leg would you use to kick a ball as far as you could?”. Each subject performed a series of single leg hops and 3-trial means of the single hop for distance (SH), timed hop (TH), and vertical hop (VH) were used for analysis. Paired samples t-test or Wilcoxon-Signed Rank test were utilized to identify differences in limb performance for each of the hop tests. Associations between self-selected and performance-based measures of limb dominance were analyzed using Chi-square. Results: A total of 352 subjects (55% male(n=191), mean age=11.1) were included. There was a small but statistically significant difference in side-to-side performance for all hop tests with a mean difference of 2.58cm(p<0.001) for SH, 0.13s(p<0.001) for TH and 0.29cm(p=0.03) for VH. There was limited agreement between self-selected and performance-based limb dominance across all hop tests (55%SH, 54%VH, and 66%TH). Similarly, Chi-square analysis revealed no associations (p>0.05) between self-selected and performance-based limb dominance across all hop test constructs. Conclusions: Although a single limb did perform better on all hop tests, the mean differences were small, and likely not clinically relevant. Perceived limb dominance did not predict performance regardless of hopping task. These findings illustrate that equality of performance can be considered normal for young athletes recovering from lower extremity injury. This information also brings into question the appropriateness of holding the perceived dominant limb to higher standards or accepting lower standards for the non-dominant limb. Tables and Figures: [Table: see text][Figure: see text] References: Goekeler A, Welling W, Benjaminse A. A critical analysis of limb symmetry indices of hop tests in athletes after anterior cruciate ligament reconstruction: a case control study. Orthop Traumatol Surg Res. 2017;103(6):947-951. doi: 10.1016/j.otsr.2017.02.015 Losciale JM, Zdeb RM, Ledbetter L, Reiman MP, Sell TC. The Association Between Passing Return-to-Sport Criteria and Second Anterior Cruciate Ligament Injury Risk: A Systematic Review With Meta-analysis. Journal of Orthopaedic & Sports Physical Therapy. 2019;49(2):43-54. doi:10.2519/jospt.2019.8190 Mulrey CR, Shultz SJ, Ford KR, Nguyen A-D, Taylor JB. Methods of Identifying Limb Dominance in Adolescent Female Basketball Players. Clinical Journal of Sport Medicine. 2018;Publish Ahead of Print. doi:10.1097/jsm.0000000000000589 van Melick N, Meddeler BM, Hoogeboom TJ, Maria W. G. Nijhuis-Van Der Sanden, Cingel REHV. How to determine leg dominance: The agreement between self-reported and observed performance in healthy adults. Plos One. 2017;12(12). doi:10.1371/journal.pone.0189876 Velotta, J. & Weyer, J. & Ramirez, A. & Winstead, J. & Bahamonde, Rafael. Relationship between leg dominance tests and type of task. Portugese J Sport Sci. 2011;11(1035-1038). Wellsandt E, Failla MJ, Snyder-Mackler L. Limb symmetry indexes can overestimate knee function after anterior cruciate ligament injury. J Orthop Sports Phys Ther. 2017;47(5):334-338.

AI with Robotics for leg support to skiers and snowboarders

In general, Robotics is the area concerned with the linking of perception to action, and AI must have a central role in Robotics if the association is to be intelligent. Skiing and Snowboarding are famous winter games worldwide, enjoyed by participants of all ages and skill levels. Leg dominance has been recounted as a probable risk factor in downhill skiers for lower-limb injuries. Furthermore, snowboarders are more likely to injure their ankles than alpine skiers. To overcome these issues, in this paper, the Artificial Intelligence assisted Statistical model (AIASM) has been proposed to the smart robotic supporting leg for skiers and snowboarders. This paper introduces the concept and study of a robotic modular leg (RML) system with a reduced degree of freedom (DOF). The RML gives a perspective on physics that uses dynamic skiing methods and strategies to produce functional ski movements. Kinematic and dynamic models for the leg system are developed and used for modeling tendency, angle, and measurement, unweighting technique to create balanced and realistic curvature turns and peaks. The experimental results show that the suggested system has a performance rate of 95.31% with different ski movements at various intervals, curves, diameters, and peak shapes for tracking the desired footpath.

Effect of Leg Dominance on Medium- to Long-Term Functional Outcomes, Quality of Life, and Revision Rates After Isolated ACL Reconstruction

Background: The effect of leg dominance on short-term functional outcomes and return to sports after arthroscopic anterior cruciate ligament reconstruction (ACLR) has been evaluated. However, postoperative medium- to long-term recovery and revision rates are not well known. Purpose: To investigate whether leg dominance affects medium- to long-term clinical and functional scores and revision rates after ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: Included in this study were 235 patients (205 male and 30 female) who underwent isolated arthroscopic ACLR. Patients were divided according to the leg dominance status of their injured limb into 2 groups: dominant leg injured (120 patients) and nondominant leg injured (115 patients). Preoperative and postoperative functional outcomes and health-related quality of life (HRQoL) were evaluated using the visual analog scale for pain, Tegner activity scale, Lysholm knee score, International Knee Documentation Committee (IKDC) subjective knee evaluation form, 36-Item Short Form Health Survey (SF-36), and overall patient satisfaction. Moreover, the revision rates of the 2 groups were compared according to leg dominance, patient characteristics, and operative features. Results: The mean follow-up period was 8.0 ± 2.3 years (range, 5-13 years). A significant preoperative to postoperative improvement in range of motion and functional scores was noticed in both groups ( P < .001 for all). However, the improvement was significantly higher in the dominant leg group for the Tegner ( P = .001), Lysholm ( P = .006), and IKDC ( P < .001) scores as well as for the SF-36 domain scores for general health ( P = .009), social role ( P = .048), and emotional role ( P = .032). Also, patient satisfaction was significantly higher in the dominant leg group ( P = .007). The dominant leg group was associated with a lower revision rate compared with the nondominant leg group (5.8% vs 15.7%, respectively; P = .015). Conclusion: High recovery rates were seen after arthroscopic ACLR, regardless of leg dominance. However, leg dominance had a significant effect on postoperative medium- to long-term functional outcomes, HRQoL, and revision rates.