Special Issue "Symmetry and Biomechanics"

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Biology and Symmetry/Asymmetry".

Deadline for manuscript submissions: closed (30 June 2021) | Viewed by 14520

Special Issue Editor

Prof. Dr. Nejc Šarabon
E-Mail Website
Guest Editor
Faculty of Health Sciences, University of Primorska, 6310 Izola, Slovenija
Interests: human movement; aging; injuies prevention; rehabilitation; ergonomics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The symmetrical structure and function of the human body is essential for performing safe, efficient, and purposeful movements in sport, at the workplace, or during the activities of daily life. Asymmetries in motor abilities and function are especially prevalent among athletes, and are related to decreased performance and movement efficiency. Asymmetries can be local (involving a single joint, muscle, or body part) or global (complex movement patterns involving the whole/majority of the body). Structural and functional asymmetries may lead to overload of the musculoskeletal system during cyclic (e.g., running and cycling) or discrete (e.g., jump) movements; however, the cause–effect relationships between asymmetries and injury risk have not been established.

In this Special Issue, we invite papers exploring and discussing the topic of body (a)symmetry and their importance for athletes or human movement in general. We welcome papers exploring the prevalence of asymmetries in different populations, associations between different asymmetries (e.g., local or global; asymmetries in structure, strength, power, stability, flexibility, movement kinematics or other aspects), relationships between asymmetries and quality of movement, sports performance and injury risk, and methodological as well as interventional studies concerning human body (a)symmetries.

Prof. Dr. Nejc Sarabon
Guest Editor

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Keywords

  • symmetry
  • human movement
  • injury prevalence
  • risk factor
  • athletes
  • movement quality
  • movement efficiency
  • movement safety

Published Papers (16 papers)

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Research

Article
Relationship between Asymmetries Measured on Different Levels in Elite Basketball Players
Symmetry 2021, 13(8), 1436; https://doi.org/10.3390/sym13081436 - 05 Aug 2021
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Abstract
In this study, we investigated the association of magnitude and agreement in direction between asymmetries measured on single-joint (hip and trunk), complex movement (jumping), and skill (change of direction (CoD)) levels. The study sample comprised 43 junior- and senior-level (age = 20.5 ± [...] Read more.
In this study, we investigated the association of magnitude and agreement in direction between asymmetries measured on single-joint (hip and trunk), complex movement (jumping), and skill (change of direction (CoD)) levels. The study sample comprised 43 junior- and senior-level (age = 20.5 ± 6.0 years; height = 194.5 ± 7.2 cm; body mass = 86.8 ± 10.1 kg) elite male basketball players. Both limbs/sides were tested in hip and trunk isometric strength; passive range of motion (RoM); unilateral, horizontal, and vertical jumping; and CoD tests, from which asymmetry indexes were calculated. The associations between asymmetry magnitudes were calculated with Spearman’s ρ correlation coefficient. The agreement between the direction of asymmetries on different levels was calculated with Cohen’’s Kappa (κ) coefficient. The average magnitude of asymmetry varied substantially (2.9–40.3%). Most associations between asymmetry magnitudes measured on different levels were small and statistically non-significant, with a few exceptions of moderate and large associations. Asymmetry in single-leg countermovement jump parameters was strongly associated with hip abduction maximal strength (ρ = 0.58 and 0.50, p < 0.01). Agreement between asymmetry directions was slight to fair, with a few moderate exceptions. Results indicate that multiple tests are needed to obtain a comprehensive picture of athletes’ asymmetries and that universal thresholds and golden standard tests for return to play should be reconsidered and reinvestigated. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Effects of a Targeted Exercise Program on Inter-Leg Asymmetries in Patients with Patellofemoral Pain
Symmetry 2021, 13(6), 1075; https://doi.org/10.3390/sym13061075 - 16 Jun 2021
Viewed by 789
Abstract
Patellofemoral pain (PFP) is often associated with impaired muscle strength, flexibility, and stability. It has been suggested that inter-leg asymmetries have an important role in increasing the risk of musculoskeletal injuries, including PFP. Thus, the aim of this study was to identify significant [...] Read more.
Patellofemoral pain (PFP) is often associated with impaired muscle strength, flexibility, and stability. It has been suggested that inter-leg asymmetries have an important role in increasing the risk of musculoskeletal injuries, including PFP. Thus, the aim of this study was to identify significant asymmetries and determine the effects of a symmetry targeted exercise program in patients with PFP. Eighteen patients aged 13 to 54 years (24.17 ± 12.52 years) with PFP participated in this study. Strength, flexibility and stability outcomes of the trunk, hip, knee and ankle muscles were assessed. A single-group pretest–posttest design was used to assess changes in inter-leg and agonist–antagonist asymmetries resulting from the 8-week period of the supervised exercise program. Results indicated a significant improvement in inter-leg symmetry regarding bilateral stance in a semi-squat position (p = 0.020, d = 0.61, df = 17) and ankle plantarflexion (p = 0.003, d = 0.32, df = 17) and ankle dorsiflexion strength (p < 0.001, d = 0.46, df = 17). In addition, the ratio of ankle dorsiflexion/plantarflexion (p = 0.036, d = 1.14, df = 17) and hip extension/flexion (p = 0.031, d = 0.94, df = 16) changed significantly during the intervention period. To our knowledge, this was the first study to evaluate inter-leg asymmetries resulting from a period of a supervised exercise program. The results indicate that an exercise program focusing on individual asymmetries may influence specific deficits and contribute to better rehabilitation outcomes. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Individuals with Unilateral Mild-to-Moderate Hip Osteoarthritis Exhibit Lower Limb Kinematic Asymmetry during Walking But Not Sit-to-Stand
Symmetry 2021, 13(5), 768; https://doi.org/10.3390/sym13050768 - 28 Apr 2021
Cited by 1 | Viewed by 646
Abstract
Asymmetry during gait is associated with the evolution of secondary osteoarthritis. Kinematic asymmetry has been reported in advanced stages of hip osteoarthritis but has not been evaluated in earlier stages of the disease or has it been directly compared with unilateral and bilateral [...] Read more.
Asymmetry during gait is associated with the evolution of secondary osteoarthritis. Kinematic asymmetry has been reported in advanced stages of hip osteoarthritis but has not been evaluated in earlier stages of the disease or has it been directly compared with unilateral and bilateral hip osteoarthritis. Our objective was to evaluate within-group symmetry and compare between-group asymmetry for three-dimensional pelvis, hip, knee, and ankle kinematics during walking and sit-to-stand in individuals with unilateral mild-to-moderate hip OA, bilateral mild-to-moderate hip osteoarthritis, and healthy controls. Twelve individuals with unilateral mild-to-moderate hip OA, nine individuals with bilateral mild-to-moderate symptomatic and radiographic hip OA, and 21 age-comparable healthy controls underwent three-dimensional motion analysis during walking and sit-to-stand. Pelvis and lower limb joint angles were calculated using inverse kinematics and between-limb symmetry was assessed for each group. Any resulting asymmetries (most affected minus contralateral limb) were compared between groups. Participants with unilateral hip osteoarthritis exhibited significantly less hip extension (7.90°), knee flexion (4.72°), and anterior pelvic tilt (3.38°) on their affected limb compared with the contralateral limb during the stance phase of walking. Those with unilateral hip osteoarthritis were significantly more asymmetrical than controls for sagittal plane hip and pelvis angles. No significant asymmetries were detected within- or between-groups for sit-to-stand. Individuals with unilateral hip osteoarthritis exhibited lower limb asymmetries consistent with those reported in advanced stages of disease during walking, but not sit-to-stand. Consideration of the possible negative effects of gait asymmetry on the health of the affected and other compensating joints appears warranted in the management of hip OA. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Tropism of Sub-Axial Cervical Facet Joints Is Not Related to Segmental Movement during Active Movement or Therapist-Perceived Symptomatic Locations
Symmetry 2021, 13(5), 739; https://doi.org/10.3390/sym13050739 - 22 Apr 2021
Cited by 1 | Viewed by 589
Abstract
Tropism, or asymmetry, of facet joints in the cervical spine has been found to be related to degenerative changes of the joints and discs. Clinicians often assume that differences in segmental mobility are related to tropism. The aims of this study were to [...] Read more.
Tropism, or asymmetry, of facet joints in the cervical spine has been found to be related to degenerative changes of the joints and discs. Clinicians often assume that differences in segmental mobility are related to tropism. The aims of this study were to determine the relationship between asymmetry of facet joints in the sub-axial cervical spine and (1) segmental mobility and (2) spinal levels perceived by therapists to have limited mobility. Eighteen participants with idiopathic neck pain had MRIs of their cervical spine in neutral and at the end of active rotation. Angular movement and translational movement of each motion segment was calculated from 3D segmentations of the vertebrae. A plane was fitted to the facet on each side. Tropism was considered to be the difference in the orientation of the facet planes and ranged from 1 to 30° with a median of 7.7°. No relationships were found between the extent of tropism and either segmental movement or locations deemed to be symptomatic. Tropism in the sub-axial cervical spine does not appear to be related to segmental mobility in rotation or to levels deemed to be symptomatic. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence
Symmetry 2021, 13(4), 705; https://doi.org/10.3390/sym13040705 - 17 Apr 2021
Viewed by 630
Abstract
Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a [...] Read more.
Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
The Relationship between Symmetrical and Asymmetrical Jumps and Their Influence on Speed Abilities: Gender Consideration
Symmetry 2021, 13(4), 694; https://doi.org/10.3390/sym13040694 - 16 Apr 2021
Cited by 1 | Viewed by 622
Abstract
Purpose: Plyometric exercises, in the form of jumping, are extreme physical activities. The aim of the study was to determine how symmetrical-single versus asymmetrical-continued plyometric exercises differ between men and women and affect speed abilities. Methods: Twenty-two healthy females and forty-four males from [...] Read more.
Purpose: Plyometric exercises, in the form of jumping, are extreme physical activities. The aim of the study was to determine how symmetrical-single versus asymmetrical-continued plyometric exercises differ between men and women and affect speed abilities. Methods: Twenty-two healthy females and forty-four males from different sports practices participated in the investigation. The countermovement jump (CMJ) and drop jump (DJ) of 40/60 cm box were performed on two independent and synchronized force platforms (Bilateral Tensiometric Platform S2P, Ljubljana, Slovenia). The measurement of a standing long jump (SLJ) and all continuous jumps: standing five jumps (SFJ), standing bounce triple jump (SBTJ), five double-leg jumps (FD-LJ), and a 10 m horizontal single leg jump (HSLJ-10mL/R) were performed using OptoJump–Next Microgate (OptoJump, Bolzano, Italy). Results: Statistically significant differences were noted in all jump kinematic and somatic parameters, in favor of the men. The correlations between values of height of symmetrical jumps (bilateral) and distance (SLJ) were stronger in women despite the shorter jumps than the men. When an alpha-level of 0.01 was set, this study demonstrated a stronger correlation between symmetrical-single and asymmetrical-continuous plyometrics exercises and sprints, both men and women. This relationship is due to their similar kinematic and dynamic structures with sprinting steps. Conclusions: The results showed a large dispersion of the relationship (p < 0.05) between jumps and sprints divided into 10, 20 and 30 m, both in men and women. Both types of exercises implemented as a plyometric training regime are an extremely important tool for sprint speed development. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
Article
Biomechanical Symmetry during Drop Jump Landing and Takeoff in Adolescent Athletes Following Recent Anterior Cruciate Ligament Reconstruction
Symmetry 2021, 13(4), 639; https://doi.org/10.3390/sym13040639 - 10 Apr 2021
Cited by 1 | Viewed by 789
Abstract
This study investigated asymmetry between lower extremities during the landing and takeoff phases of a vertical drop jump (VDJ) in adolescent athletes following anterior cruciate ligament reconstruction (ACLR) and examined if performance was affected by reducing jump height. Thirty-three athletes who underwent ACLR [...] Read more.
This study investigated asymmetry between lower extremities during the landing and takeoff phases of a vertical drop jump (VDJ) in adolescent athletes following anterior cruciate ligament reconstruction (ACLR) and examined if performance was affected by reducing jump height. Thirty-three athletes who underwent ACLR and were referred for 3D biomechanical assessment before returning to play (mean age 15.9, SD 1.3 years; 16/33 female; mean time since surgery 7.4, SD 1.2 months) completed the VDJ while kinematics and kinetics were collected using motion capture. Lower extremity symmetry was compared between phases using paired t-tests. Jump height was calculated to measure performance. Asymmetries in ankle inversion, ankle adduction, knee adduction, hip adduction, hip adduction moment, and hip rotation moment were observed in both phases. Asymmetry was also observed in both phases for sagittal moments and power integrals at the knee and ankle and total power integral, with the magnitude of asymmetry being smaller during takeoff for power absorption/generation. Jump height was related to power generation integrals during takeoff but not to the asymmetry of power generation. Since asymmetries are translated from landing through takeoff, rehabilitation should address both phases to decrease injury risk and maximize performance after return to play. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Asymmetry in Three-Dimensional Sprinting with and without Running-Specific Prostheses
Symmetry 2021, 13(4), 580; https://doi.org/10.3390/sym13040580 - 01 Apr 2021
Cited by 1 | Viewed by 646
Abstract
As a whole, human sprinting seems to be a completely periodic and symmetrical motion. This view is changed when a person runs with a running-specific prosthesis after a unilateral amputation. The aim of our study is to investigate differences and similarities between unilateral [...] Read more.
As a whole, human sprinting seems to be a completely periodic and symmetrical motion. This view is changed when a person runs with a running-specific prosthesis after a unilateral amputation. The aim of our study is to investigate differences and similarities between unilateral below-knee amputee and non-amputee sprinters—especially with regard to whether asymmetry is a distracting factor for sprint performance. We established three-dimensional rigid multibody models of one unilateral transtibial amputee athlete and for reference purposes of three non-amputee athletes. They consist of 16 bodies (head, ipper, middle and lower trunk, upper and lower arms, hands, thighs, shanks and feet/running specific prosthesis) with 30 or 31 degrees of freedom (DOFs) for the amputee and the non-amputee athletes, respectively. Six DOFs are associated with the floating base, the remaining ones are rotational DOFs. The internal joints are equipped with torque actuators except for the prosthetic ankle joint. To model the spring-like properties of the prosthesis, the actuator is replaced by a linear spring-damper system. We consider a pair of steps which is modeled as a multiphase problem with each step consisting of a flight, touchdown and single-leg contact phase. Each phase is described by its own set of differential equations. By combining motion capture recordings with a least squares optimal control problem formulation including constraints, we reconstructed the dynamics of one sprinting trial for each athlete. The results show that even the non-amputee athletes showed less symmetrical sprinting than expected when examined on an individual level. Nevertheless, the asymmetry is much more pronounced in the amputee athlete. The amputee athlete applies larger torques in the arm and trunk joints to compensate the asymmetry and experiences a destabilizing influence of the trunk movement. Hence, the inter-limb asymmetry of the amputee has a significant effect on the control of the sprint movement and the maintenance of an upright body position. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Walking on a Vertically Oscillating Platform with Simulated Gait Asymmetry
Symmetry 2021, 13(4), 555; https://doi.org/10.3390/sym13040555 - 27 Mar 2021
Viewed by 697
Abstract
Asymmetric gait is associated with pain, injury, and reduced stability in patient populations. Data from side by side walking suggest that unintentional synchronization with an external cue may reduce gait asymmetry. Two types of asymmetric gait were examined here: (1) mass imbalance between [...] Read more.
Asymmetric gait is associated with pain, injury, and reduced stability in patient populations. Data from side by side walking suggest that unintentional synchronization with an external cue may reduce gait asymmetry. Two types of asymmetric gait were examined here: (1) mass imbalance between limbs to simulate single limb amputation and (2) restriction of plantarflexion during toe-off to simulate reduced propulsion from neurological impairment. Twenty-five healthy participants walked normally and with simulated gait asymmetry on a custom-designed treadmill that oscillated in the vertical direction via pneumatic actuation (amplitude: 2 cm, frequency: participant’s preferred step frequency). Swing Time Asymmetry (STA) and Phase Coordination Index (PCI) both increased significantly with the application of unilateral mass and plantarflexion restriction (p < 0.001). However, walking with simulated asymmetry did not alter unintentional synchronization with the treadmill motion. Further, oscillation of the treadmill did not improve STA or PCI while walking with simulated asymmetry. Analysis of synchronized step clusters using the Weibull survival function revealed that synchronization with the platform persisted for longer durations when compared with data from side by side walking. These results suggest that walking on a vertically oscillating surface may not be an effective approach for improving gait asymmetry. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Gait Symmetry Analysis in Patients after Treatment of Pilon Fractures by the Ilizarov Method
Symmetry 2021, 13(2), 349; https://doi.org/10.3390/sym13020349 - 21 Feb 2021
Cited by 2 | Viewed by 732
Abstract
The aim of this study was to comprehensively assess the gait parameters in patients who had undergone treatment of pilon fractures by the Ilizarov method. We analyzed gait parameters in patients who had undergone treatment for pilon fractures by the Ilizarov method; 20 [...] Read more.
The aim of this study was to comprehensively assess the gait parameters in patients who had undergone treatment of pilon fractures by the Ilizarov method. We analyzed gait parameters in patients who had undergone treatment for pilon fractures by the Ilizarov method; 20 patients aged 47.0 years (25.2–78.6) were included in the study. The control group consisted of 32 healthy volunteers. Gait examination was performed using the pedobarographic platform. Statistically significant differences in the following gait parameters: maximum forefoot force (%), step length (cm), and step time (s) were found between the study group and the control group, between the nonoperated leg, and both the operated leg and the dominant limb. Statistically significant differences in the study group between the treated lower limb and the healthy lower limb were only observed in the case of the maximum forefoot force parameter (%). Healthy subjects from the control group obtained significantly higher values during locomotion for stride time, cadence step, and velocity than the patients, with stride time being statistically significantly shorter and the velocity and the cadence step higher. We observed symmetry in the gait parameters after treating pilon fractures by the Ilizarov method. This method of stabilization allows the restoration of gait parameters, with results similar to those obtained after the treatment of other motor organ pathologies described in the literature, although different from those observed in healthy subjects. In particular, the biomechanics of the lower limbs remain disturbed. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Influence of Load and Phase of Contraction on Lateral Symmetries in Flywheel Squats
Symmetry 2021, 13(1), 111; https://doi.org/10.3390/sym13010111 - 11 Jan 2021
Cited by 2 | Viewed by 688
Abstract
Assessment of lateral symmetries (LS) of lower limbs has been widely investigated. However, there are no studies about LS during exposure to high eccentric and concentric loads during flywheel (FW) squats. A total of 422 young, physically active participants performed squats on an [...] Read more.
Assessment of lateral symmetries (LS) of lower limbs has been widely investigated. However, there are no studies about LS during exposure to high eccentric and concentric loads during flywheel (FW) squats. A total of 422 young, physically active participants performed squats on an FW device with different equidistant loads (0.05, 0.125 and 0.2 kg∙m2). The mean and peak force of the left and right leg were assessed for the concentric and eccentric contaction phase. LS values were calculated for each load and phase of squat. Our results showed that the absolute mean and peak force of the concentric and eccentric phase of contraction had excellent reliability, while LS values were more reliable when eccentric force was used for their calculation. Mean and peak forces were increased with the higher FW load. In general, we found a decrease in LS values in the concentric phase of contraction with the higher load. Moreover, values of LS are similar to a wide range of other functional movements. Nevertheless, symmetrical force application during squatting on a FW device should be satisfied regardless of the FW load. Due to the large sample size, our results are valuable as a reference point when athletes are evaluated during training. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
An Evaluation of Symmetries in Ground Reaction Forces during Self-Paced Single- and Dual-Task Treadmill Walking in the Able-Bodied Men
Symmetry 2020, 12(12), 2101; https://doi.org/10.3390/sym12122101 - 17 Dec 2020
Cited by 2 | Viewed by 1194
Abstract
Gait is a complex autonomous activity that has long been viewed as a symmetrical locomotion, even when it adapts to secondary concurrent attention-demanding tasks. This study aimed to evaluate the symmetry of the three ground reaction forces (GRFs) in able-bodied individuals during self-paced [...] Read more.
Gait is a complex autonomous activity that has long been viewed as a symmetrical locomotion, even when it adapts to secondary concurrent attention-demanding tasks. This study aimed to evaluate the symmetry of the three ground reaction forces (GRFs) in able-bodied individuals during self-paced treadmill walking with and without concurrent cognitive demands. Twenty-five male participants (age: 34.00 ± 4.44 years) completed two gait assessment sessions, each of whom were familiarized with the walking trials during their first session. Both sessions involved six-minute self-paced treadmill walking under three conditions: single-task walking and walking while concurrently responding to auditory 1-back and 2-back memory tasks. The symmetry of the GRFs was estimated using a nonlinear approach. Changes in the symmetry and walking speed across conditions in both sessions were assessed using inferential statistics. Results demonstrated that the three GRFs deviated from perfect symmetry by ≥10%. Engaging working memory during walking significantly reduced the symmetry of the vertical GRF (p = 0.003), and its detrimental effects on walking speed were significantly reduced in the second session with respect to the first session (p < 0.05). The findings indicate imperfect gait symmetry in able-bodied individuals, suggesting that common perceptions of gait symmetry should be reconsidered to reflect its objective importance in clinical settings. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Relationship between Inter-Limb Asymmetries and Physical Performance in Rink Hockey Players
Symmetry 2020, 12(12), 2035; https://doi.org/10.3390/sym12122035 - 09 Dec 2020
Cited by 4 | Viewed by 855
Abstract
The magnitude of inter-limb asymmetries has been reported in several studies in different team sports but only some of them have analysed their effects on sports performance. The main purpose of this cross-sectional study was to determine inter-limb asymmetries and examine their relationship [...] Read more.
The magnitude of inter-limb asymmetries has been reported in several studies in different team sports but only some of them have analysed their effects on sports performance. The main purpose of this cross-sectional study was to determine inter-limb asymmetries and examine their relationship with different physical performance tests in rink hockey players. Nineteen rink hockey players (age: 23.37 ± 4.82 years; body height: 1.75 ± 0.06 cm; body mass: 73.16 ± 9.87 kg) performed a mid-season battery of fitness tests consisting of 30 m sprint, countermovement jump (CMJ), and half back squat. Inter-limb asymmetries were assessed using the single leg vertical countermovement jump test (SLCJ-V), single leg horizontal countermovement jump test (SLCJ-H), and 180° change of direction test (COD). Results show a significant relationship between asymmetry in the SLCJ-H test, 30 m sprint (r = 0.63, p < 0.01) and CMJ performances (r = −0.52, p < 0.05). Additionally, asymmetry in the SLCJ-V showed a significant relationship with CMJ performance (r = −0.46, p < 0.05). These findings suggest that training programs should aim to reduce the inter-limb asymmetries in rink hockey players to improve their performance. Practitioners and coaches can use this information to assess the potential impact of asymmetries on physical performance in rink hockey players. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Inter-Limb Symmetry at Simultaneous and Alternated Arms Flexion by the Elbow during Water Fitness Sessions
Symmetry 2020, 12(11), 1776; https://doi.org/10.3390/sym12111776 - 27 Oct 2020
Cited by 2 | Viewed by 865
Abstract
The aim was to compare the inter-limb symmetry between alternated and simultaneous arms flexion during water fitness sessions. Twenty-three elderly women were recruited to perform flexion by the elbow with different mechanical strategies: (a) simultaneous and (b) alternated. An incremental protocol was used, [...] Read more.
The aim was to compare the inter-limb symmetry between alternated and simultaneous arms flexion during water fitness sessions. Twenty-three elderly women were recruited to perform flexion by the elbow with different mechanical strategies: (a) simultaneous and (b) alternated. An incremental protocol was used, with four music cadences, starting at 105 beats per minute up to 150. The peak force of dominant and non-dominant upper-limbs was retrieved. A symmetry index (SI, %) was also used to quantify coordination. There were significant variations in force produced by the dominant and non-dominant limbs in most of the cadences in the alternated or simultaneous actions. Differences with a medium effect between upper-limbs were shown when moving simultaneously indicating that an alternated movement can be a more proper strategy to work with. Despite that, both strategies seemed to be characterized by an asymmetric pattern (SI from 20 to 30%), requiring full attention from water fitness practitioners. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Article
Strength, Jumping and Change of Direction Speed Asymmetries in Soccer, Basketball and Tennis Players
Symmetry 2020, 12(10), 1664; https://doi.org/10.3390/sym12101664 - 12 Oct 2020
Cited by 12 | Viewed by 1603
Abstract
Despite growing research in the field of inter-limb asymmetries (ILAs), little is known about the variation of ILAs in different populations of athletes. The purpose of this study was to compare ILAs among young basketball, soccer and tennis players. ILAs were assessed in [...] Read more.
Despite growing research in the field of inter-limb asymmetries (ILAs), little is known about the variation of ILAs in different populations of athletes. The purpose of this study was to compare ILAs among young basketball, soccer and tennis players. ILAs were assessed in three different types of tests (strength, jumping and change of direction (CoD) speed), each including different tasks: (1) bilateral and unilateral counter movement jump, (2) isometric strength of knee extensors (KE) and knee flexors (KF), and (3) 90° and 180° CoD. Generally, the absolute metrics showed strong reliability and revealed significant differences (p < 0.05) among the three groups in KE maximal torque, KE and KF rate of force development and in both CoD tests. For jumping ILAs, power and force impulse metrics exhibited significant between-limb differences between groups, compared to jump height. For strength and CoD speed ILAs, only KF maximal torque and 180° CoD exhibited significant differences between groups. Greater KF strength ILAs in soccer players and counter-movement jump ILAs in tennis players are most probably the result of sport-specific movement patterns and training routines. Sport practitioners should be aware of the differences in ILAs among sports and address training programs accordingly. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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Communication
Interlimb Asymmetries and Ipsilateral Associations of Plantar Flexors and Knee Extensors Rate-of-Force Development Scaling Factor
Symmetry 2020, 12(9), 1522; https://doi.org/10.3390/sym12091522 - 16 Sep 2020
Cited by 5 | Viewed by 1120
Abstract
Rate of force/torque development scaling factor (RFD-SF/RTD-SF) was recently introduced as a tool to quantify the neuromuscular quickness, and it could have potential for interlimb asymmetry identification. Moreover, positive relationships in RFD-SF ability among different muscle groups were shown, but not in the [...] Read more.
Rate of force/torque development scaling factor (RFD-SF/RTD-SF) was recently introduced as a tool to quantify the neuromuscular quickness, and it could have potential for interlimb asymmetry identification. Moreover, positive relationships in RFD-SF ability among different muscle groups were shown, but not in the lower extremity. The first aim of our study was to use RTD-SF for interlimb asymmetry identification. The second aim was to determine associations between plantar flexors (PF) and knee extensors (KE). Forty young healthy athletes (14.8 ± 1.2 years) performed explosive isometric contractions to a span of torque levels for PF and KE. From rapid isometric contractions, the RTD-SF and linearity (r2) of the regression line were calculated. Using RTD-SF we identified 10% (PF) and 15% (KE) of subjects with contralateral asymmetries (>15% criterion). The results revealed significant positive moderate correlation in RTD-SF between PF and KE (r = 0.401, p < 0.05). We supported that RTD-SF can be a useful tool for interlimb asymmetry identification. Future research about observed asymmetry in rapid submaximal contractions deserves more attention, as most of the functional sport specific activities put high demands on rapid force production. Our study as first confirmed positive associations in RTD-SF ability between muscle groups in lower limbs. Full article
(This article belongs to the Special Issue Symmetry and Biomechanics)
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