Strength Asymmetry Research Articles

Ability of Countermovement Jumps to Detect Bilateral Asymmetry in Hip and Knee Strength in Elite Youth Soccer Players

Clinicians frequently assess asymmetry in strength, flexibility, and performance characteristics as a method of screening for potential musculoskeletal injury. The identification of asymmetry in countermovement jumps may be an ideal method to reveal asymmetry in other lower extremity characteristics such as strength that otherwise may require additional testing, potentially reducing the time and burden on both the athlete and clinicians. The present study aims to examine the ability of asymmetry in both the single-leg and two-leg countermovement jump tests to accurately detect hip abduction, hip adduction, and eccentric hamstring strength asymmetry. Fifty-eight young male elite soccer players from the same professional academy performed a full battery of functional performance tests which included an assessment of hip adductor and abductor strength profiles, eccentric hamstring strength profiles, and neuromuscular performance and asymmetries during countermovement jumps. Bilateral variables attained from both the single-leg and two-leg countermovement jump tests included concentric impulse (Ns), eccentric mean force (N), and concentric mean force (N) computed by the VALD ForceDecks software. Average maximal force (N) was calculated bilaterally for the strength assessments. Asymmetry was calculated for each variable using 100 × |(right leg - left leg)/(right leg)| and grouped into three categories: 0 to <10%, 10% to <20%, and 20% or greater. Analyses were performed for the two higher asymmetry groups. The accuracy to detect strength asymmetry was assessed as the sensitivity, specificity, and predictive values for positive and negative tests. The outcomes from the accuracy assessments suggest that the single-leg countermovement jump concentric impulse variable at the 20% threshold is indicative of a youth male soccer player having hip adduction strength asymmetry while also demonstrating more accuracy and applicability than the two-leg countermovement jump concentric impulse variable.

Adapting in the Arctic II: Upper limb diaphyseal robusticity and habitual activity in Late Holocene hunter-gatherers from Alaska.

This study compares humeral diaphyseal robusticity and asymmetry between Late Holocene hunter-gatherers from Alaska with the goal of reconstructing habitual activity in relation to culture and environment. Ancestral remains from four geographic regions of Alaska were divided into five site groups defined by subsistence strategies and technology: Aleutian Islands, Coastal Bay, Far North Coastal, Inland/Riverine, and Tikeraq. Mid-distal humeral diaphyseal robusticity was quantified using cross-sectional geometric properties standardized by estimated body mass and bone length. Humeral strength and bilateral asymmetry were greatest in Aleutian Island males, moderate in Far North Coastal and Tikeraq males, and reduced in Inland/Riverine males. Left-biased directional asymmetry and reduced humeral strength were found in Coastal Bay males. Aleutian Island males had relatively mediolaterally strengthened humeri compared with other groups. Aleutian Island females had elevated humeral strength, while humeral asymmetry among females was moderate and did not vary between groups. Humeri were relatively round among Aleutian Island and Tikeraq females and anteroposteriorly (A-P) strengthened among Coastal Bay, Far North Coastal, and Inland/Riverine females. These results suggest elevated humeral strength and asymmetry in males that engaged in rowing and unimanual projectile hunting, while reduced humeral strength and asymmetry may reflect bow-and-arrow or ensnarement technologies. Left-biased humeral asymmetry may be associated with net-fishing. Humeral strength and asymmetry are consistent with select instances of unimanual projectile hunting in females, while differences in humeral A-P/mediolateral strength may reflect variation in butchery and processing of prey versus rowing and throwing behaviors.

Identification of potential risk factors for lower limb injuries in female team-sport athletes: a prospective cohort study

ABSTRACT Objectives The purpose of this prospective cohort study was to assess the associations between lower limb injuries in female team-sport athletes and a number of factors. The potential risk factors explored included (1) lower limb strength, (2) history of life-event stress, (3) family history of ACL injuries, (4) menstrual history, and (5) history of oral contraception use. Methods One hundred and thirty-five female athletes aged between 14 and 31 years (mean: 18.8 ± 3.6 years) from rugby union (n = 47), soccer (n = 72), and netball (n = 16) volunteered to participate in this study. Demographics, history of life-event stress, injury history and baseline data were obtained prior to the competitive season. The following strength measures were collected: isometric hip adductor and abductor strength, eccentric knee flexor strength and single leg jumping kinetics. Athletes were then followed for 12 months, and all lower limb injuries sustained were recorded. Results One hundred and nine athletes provided one-year follow-up injury data, of whom, 44 suffered at least one lower limb injury. All athletes who reported high scores for negative life-event stress sustained lower limb injuries. Non-contact lower limb injury was positively associated with weak hip adductor strength (OR: 0.88; 95%CI: 0.78–0.98; p = 0.017), and between-limb adductor (OR: 5.65; 95%CI: 1.61–19.7.; p = 0.007) and abductor (OR: 1.95; 95%CI: 1.03–3.71; p = 0.039) strength asymmetries. Conclusion History of life event stress, hip adductor strength, and between-limb adductor and abductor strength asymmetries offer potential novel avenues for investigating injury risk factors in female athletes.

Yield Surfaces and Plastic Potentials for Metals, with Analysis of Plastic Dilatation and Strength Asymmetry in BCC Crystals

Since the 1980s, constitutive modeling has steadily migrated from phenomenological descriptions toward approaches that are based on micromechanics considerations. Despite significant efforts, crystal plasticity remains an open field of research. Among the unresolved issues are the anomalous behavior of metals at low temperatures and the stress upturn at extreme dynamics. This work is focused on the low-temperature responses of body-centered-cubic (bcc) metals, among them, molybdenum (Mo). At these conditions, the plastic flow strength is governed by the motion of screw dislocations. The resultant non-planarity of core structures and slip causes the following: the shear stress includes non-glide components, the Schmid law is violated, there is a tension-compression asymmetry, and the yield surface and plastic potential are clearly decoupled. We find that the behavioral complexities can be explained by atomistically resolved friction coefficients in macroscopic yield and flow. The plastic flow mechanisms establish the departure point into the follow-up analysis of yield surfaces. For example, we know that while the von Mises stress is explained based on energy considerations, we will also show that the stress has a clear geometric interpretation. Moreover, the von Mises stress is just one case within a much broader class of equivalent stresses. Possible correlations among non-Schmid effects (as represented macroscopically by friction coefficients), volume change (i.e., residual elastic dilatation) from dislocation lines, and elastic anisotropy are investigated. Extensions to the shock regime are also established.

Exhaustification in the semantics of &lt;em&gt;cause&lt;/em&gt; and &lt;em&gt;because&lt;/em&gt;

We show that a single operation can account for three seemingly distinct properties of the semantics of cause and because. The properties are, firstly, their comparative nature: interpreting cause and because involves comparing what would happen in the presence of the cause (a positive condition) with what would happen in the absence of the cause (a negative condition). Secondly, there is an asymmetry in logical strength between the two conditions: the positive condition involves a universal modal while the negative condition involves an existential modal. Thirdly, the positive and negative conditions have the same modal base, i.e. are interpreted while assuming the same set of background facts.Despite their apparent dissimilarity, we show that these three properties are predicted by a single operation: exhaustification. The comparative nature of cause and because follows from the comparative nature of exhaustification, which compares a sentence with its alternatives. The asymmetry in strength arises because exhaustification negates alternatives: given the duality between universal and existential quantification, negation flips a necessity modal into a possibility modal, producing the observed strength asymmetry. Finally, the positive and negative condition have the same modal base since, rather cause and because having two modals in their semantics—one for the positive condition and one for the negative condition—their semantics contains a single modal which is copied by exhaustification.We conclude by showing that this exhaustification operator violates Economy constraints, suggesting that it is not subject to licensing conditions but part of lexical semantics of cause and because.

Composite Score of Readiness (CSR) as a Data Reduction Technique for Monitoring the RTS Process in Footballers following ACL Reconstruction

In recent years, many studies on the safe return to sport (RTS) have been published, but there are still no clear and validated guidelines. After ACL reconstruction between limbs, asymmetry of muscle strength affects knee mechanics during walking and running, and asymmetrical joint kinematics and kinetics are considered as a strong risk factor of musculoskeletal injury. Therefore, proper diagnosis of any motor deficits remaining after ACL reconstruction seems particularly important. The aim of this study was to analyze how many tests should be included in the RTS test battery and which of them are most indicative for functional deficits related to anterior cruciate ligament (ACL) reconstruction. Sixty-five male football players (age 18–25 years) were divided into three groups: ACL group—after ACL rupture and reconstruction, mild injury group—post mild lower limb injuries, and the control group—without injuries. They performed five tests: Functional Movement Screen, Tuck Jump Assessment, Y-balance Test, Hop Test for Distance, and Isokinetic Test. The Composite Score of Readiness (CSR) index was calculated and expressed as the sum of z-scores. The multiple regression model for all tests was calculated, and then redundant variables were excluded. We observed that all tests significantly influenced the final CSR index. The Y-balance Test, Tuck Jump Assessment, and Isokinetic Test for knee flexion influenced the final CSR index the most, which means that these tests are greatly indicative of functional deficits related to ACL reconstruction. The strength of the extensor (quadriceps) muscle and the quadriceps/hamstring ratio appeared to be non-sensitive for testing functional deficits related to ACL reconstruction. If the test battery includes 4–5 tests, it better differentiates the athletes following ACL reconstruction from those after mild injuries, even if they all were cleared to play.

Technological capability strength/asymmetry and supply chain process innovation: The contingent roles of institutional environments

Despite the importance of process innovation in fostering supply chain competitiveness, existing studies primarily emphasize product innovation and overlook institutional environments. This study builds on the dyadic capability-based view and institutional theory to investigate how buyer's and supplier's technological capabilities jointly affect supply chain process innovation in China. We differentiate between two distinct dimensions, technological capability strength and technological capability asymmetry, and propose that technological capability strength negatively influences supply chain process innovation whereas technological capability asymmetry promotes such innovation. We also examine how formal (i.e., government intervention) and informal (i.e., guanxi importance) institutional factors moderate the effects of technological capability strength and asymmetry on supply chain process innovation. Empirical analyses based on 157 buyer–supplier dyads in China offer strong support for our hypotheses, which provide important implications for the supply chain innovation collaboration literature and managerial practice.

Prevalence and Trends of Handgrip Strength Asymmetry in the United States.

Strength asymmetries are a type of muscle function impairment that is associated with several health conditions. However, the prevalence of these asymmetries among adults from the United States remains unknown. We sought to estimate the prevalence and trends of handgrip strength (HGS) asymmetry in American adults. The unweighted analytic sample included 23,056 persons aged at least 50-years with information on HGS for both hands from the 2006-2016 waves of the Health and Retirement Study. A handgrip dynamometer measured HGS, with the highest recorded values for each hand used to calculate asymmetry. Persons were categorized into the following asymmetry severity categories: (1) >10%, (2) >20.0%, and (3) >30.0%. Survey weights were used to generate nationally-representative asymmetry estimates. Overall, there were no statistically significant trends in HGS asymmetry categories over time. The prevalence of HGS asymmetry in the 2014-2016 wave was 53.4% (CI: 52.2-54.4), 26.0% (CI: 25.0-26.9), and 11.7% (CI: 10.9-12.3) for asymmetry at >10%, >20%, and >30%, respectively. HGS asymmetry was generally higher in older Americans compared to middle-aged adults at each wave. In the 2014-2016 wave, >30% asymmetry prevalence was 13.7% (CI: 12.7-14.6) in females and 9.3% (CI: 8.4-10.2) in males. Some differences in asymmetry prevalence by race and ethnicity were observed. The prevalence of asymmetry was generally high, especially in women and older adults. Ongoing surveillance of strength asymmetry will help monitor trends in muscle dysfunction, guide screening for disablement, identify subpopulations at risk for asymmetry, and inform relevant interventions.

Effects of a mobility and dynamic strength intervention program on the range of motion, strength, and strength asymmetry in people with neck or low back pain

The purpose was to ascertain the effects of a 12-week intervention program based on exercises of mobility and dynamic strength on the stabilization of neck and trunk muscles in people with neck or low back pain according to gender. Forty-two subjects (n = 25 males and n = 17 females; age 49.62±8.82 years) with neck or low back pain completed a recovery-training program focused on improving mobility and strength in the stabilizing muscles of the trunk and neck. A range of motion test, a strength (maximum voluntary contraction) test and the muscle strength asymmetry of the muscle groups analyzed were assessed at the beginning (T1), after six (T2) and after 12 (T3) weeks of intervention. Improvements were seen in nine out of the 12 range of motion variables at T2 (ES=0.52 to 1.26, moderate-high; p&amp;lt;.05) and T3 (ES=-0.28 to -0.44, low; p&amp;lt;.05 or p&amp;lt;.01). Improvements were also evident in all the strength variables at T2 (ES=-0.81, high; p&amp;lt;.01) and T3 (ES=-1.08 to -0.95, high; p&amp;lt;.01). In contrast, in the strength asymmetry variables improvements were found in one out of the five variables analyzed at T2 (ES=-0.81, high; p&amp;lt;.01) and two out of five at T3 (ES=- 1.08 to -0.95, high; p&amp;lt;.01). In conclusion, the intervention was effective for improving range of motion and strength. However, to improve muscle strength asymmetry it may be necessary to include specific exercises.

Association Between Knee Extension Strength at 3 and 6Months After Anterior Cruciate Ligament Reconstruction.

Deficits in knee extension strength after anterior cruciate ligament reconstruction have been a major problem. The inadequate recovery of the knee extension strength of surgical limb reportedly delays return to sports and increases reinjury risk. Accordingly, the early detection of knee extension strength deficits after reconstruction may help plan early interventions to manage impairment. This study aimed to clarify the association between knee extension strength at 3 and 6months after anterior cruciate ligament reconstruction. Retrospective study. Fifty patients who underwent primary anterior cruciate ligament reconstruction using hamstring grafts were included. At 3months postoperatively, the limb symmetry index (LSI) of isokinetic knee extension strength (IKE) at 60°/s, degree of swelling, passive range of motion of knee flexion and extension, and anterior leg reach distance were measured. At 6 months postoperatively, the LSI of IKE was measured at 60°/s, which was used as the main outcome. A correlation analysis was performed with the LSI of IKE at 6months postoperatively as the dependent variable and the LSI of IKE at 3months postoperatively as the independent variable. Subsequently, a multiple regression analysis was performed, with LSI of IKE at 6months postoperatively as the dependent variable; LSI of IKE at 3months postoperatively as the independent variable; and other variables, demographic information, and surgical data as covariates. The correlation analysis revealed that the LSIs of IKE at 3 and 6months postoperatively were correlated (r = .535, P < .001). In the multiple regression analysis, the LSI of IKE at 3months postoperatively was significantly associated with that at 6months postoperatively, even when other variables were included as covariates (R2 = .349, P = .004). Asymmetry of knee extension strength at 3months postoperatively could be more useful than other variables related to knee strength in predicting the asymmetry of knee extension strength at 6months postoperatively.

The effects of training with unstable surfaces on the strength and inter-limb asymmetry values in young soccer players

article: The effects of training with unstable surfaces on the strength and inter-limb asymmetry values in young soccer players - Medicina dello Sport 2022 December;75(4):477-87 - Minerva Medica - Journals

Effects of reduced extrusion temperature on microstructure and mechanical properties of Mg–6Zn–0.5Zr alloy

Improving the strength of the commercial ZK60 alloys plays a key role in promoting their wide applications. In this work, a ZK60 alloy was prepared by conventional direct extrusion at an obviously reduced temperature of 180 °C. Compared with ZK60 alloys directly extruded at high temperatures (>300 °C), the studied alloy has finer dynamic recrystallized (DRXed) grains with the average size of ∼1.7 μm, stronger typical fiber texture and more profuse lath-like sub-grains. In addition, the ultra-low extrusion temperature increased dynamic precipitates (rod-like Mg4Zn7 and MgZn2) in DRXed grains. After aging, a great many of nanosized precipitates formed in both DRXed grains and non-recrystallized grains, and relatively coarse MgZn2 particles precipitated on sub-grain boundaries. As a result, the aged ZK60 alloy exhibit significantly high ultimate compressive strength of ∼675 MPa on the basis of high yield strength of ∼310 MPa, indicating a significant strain hardening capability. Meanwhile, it has excellent strength-ductility balance and a weakened tension-compression yield strength asymmetry under owning a high TYS in order of ∼400 MPa.

Investigation of Bilateral Asymmetric Isometric Strength of Knee Muscles in Iranian Women with Multiple Sclerosis

Background: Multiple sclerosis (MS) causes an asymmetric pattern in the strength of the muscles on both sides of the body. So far, the amount of asymmetry in the isometric strength of knee muscles in Iranian women with MS has not been studied. Therefore, this study aimed to investigate the extent of bilateral asymmetry in the isometric strength of knee flexor and extensor muscles in Iranian women with MS. Materials and Methods: This is a causal-comparative study. From 93 MS patients, 27 females (20-50 years with an expanded disability status scale of less than 4) were selected as the statistical sample. Maximal voluntary isometric contraction (MVIC) of the knee flexor and extensor muscles was measured at the angles of 20 and 70 degrees using a Biodex isokinetic dynamometer. The asymmetric score in muscle strength was also calculated as a percentage of the ratio between the peak torque isometric strength in the muscles of the weak leg to the strong one. The data were analyzed using the correlated t-test at the 95% confidence level. Results: The results showed a significant difference in MVIC of the knee extensor and flexor muscles between the strong and the weak leg at the angles of 20 and 70 degrees in the statistical sample of the present study (P=0.001). Additionally, in terms of asymmetry in strength, the results showed that the highest percentage of bilateral asymmetry between strong and weak legs was in the strength of knee extensor muscle at the angle of 20 degrees (31.2%), and the lowest percentage was in knee flexor muscles at 70 degrees (16.1%). Conclusion: The results of this study showed that the asymmetric rate in the strength of flexor and extensor muscles of the strong and weak leg is about 16% to 31% in Iranian women with MS with an expanded disability status scale of less than 4.

Handgrip Strength is Related to Regional Brain Volumes in a Cohort of Cognitively Impaired Older Adults with Confirmed Amyloid Burden

AbstractBackgroundHandgrip strength is important for performing activities of daily living[1]. In older adults, weaker handgrip strength and asymmetry are associated with poorer cognition. o better understand mechanisms, we sought to quantify the relationship between handgrip strength and regional volumes quantified on brain MR imaging.MethodWe selected 32 participants (mean age=70.8±7.3 [range 57‐89] years, 53.1% female, 90.6% right‐handed, mean body mass index BMI=23.9±4.1) from the Pacific Brain Health Center at Providence St. John’s Health Center, with Alzheimer dementia biomarker evidence of amyloidosis[2]. Mean Montreal Cognitive Assessment score for all participants was 21.3±3.8 points. Handgrip strength on dominant and non‐dominant hands was measured using the NIH Motor Toolbox[3] as part of a cognitive fitness assessment using a hydraulic hand dynamometer. The resulting scores included handgrip strength and percentile comparisons to normative data. Asymmetry scores were calculated. Regional brain volumes, including lobar structures and the hippocampus, were measured from T1‐weighted MR images using Neuroreader[4]. Partial correlations (rp), adjusting for age, sex, BMI and total intracranial volume modeled handgrip strength, asymmetry, and brain volumes with a significance threshold of p&lt;0.05.ResultIn the dominant hand, higher handgrip strength scores and percentiles were associated with larger volumes in the left frontal lobe (rp=+0.51, p=0.007; rp =+0.47, p=0.01) and right parietal lobe (rp=+0.40, p=0.03; rp=+0.39, p=0.04). In the non‐dominant hand, higher handgrip strength score and percentiles were associated with smaller total cerebral spinal fluid (CSF) volume (rp =‐0.55, p=0.004; rp =‐0.52, p =0.006) and larger volumes within the left hippocampus (rp=+0.45, p=0.01; rp=+.43, p=0.02), right hippocampus (rp=+0.47, p=0.01; rp=+0.43, p=0.02), and right parietal lobe (rp=+0.39, p=0.04; rp=+0.44, p=0.02). Handgrip strength asymmetry was inversely related to right hippocampal volume (rp=‐0.58, p=0.002) and positively correlated to CSF volume (rp=+0.39, p=0.04).ConclusionGreater handgrip strength was related to larger regional brain volumes. A higher number of brain regions were related to the non‐dominant hand. Asymmetry was associated with lower right hippocampal volume and higher CSF volume. Interventions focused on improving handgrip strength may seek to include quantified brain volumes on MR imaging as endpoints.

Upper Extremity Skeletal Muscle Mass Asymmetry Exacerbated by Shoulder Imbalance in Lenke1A Adolescent Idiopathic Scoliosis

Limb muscle strength asymmetry affects many physical abilities. The present study (1) quantified limb muscle asymmetry in patients with adolescent idiopathic scoliosis (AIS); (2) compared AIS patients with major thoracolumbar/lumbar (TL/L) or major thoracic (MT) curves; (3) examined correlations between limb muscle asymmetry and radiographic parameters. Patients with AIS with major TL/L curves (Lenke type 5C) and MT curves (Lenke Type 1A) who underwent posterior spinal fusion at our university hospitals were included. Patients with left hand dominance were excluded. Body composition was measured using whole-body dual-energy X-ray absorptiometry and asymmetry of left and right side skeletal muscles were evaluated. Upper extremity skeletal muscles on the dominant side were significantly larger than those on the nondominant side in both Lenke1A and 5C groups. The asymmetry of upper extremity skeletal muscles was significantly greater in the Lenke1A group than in the Lenke5C group. Additionally, the size of the asymmetry did not correlate with the magnitude of the major curve and rotational deformation but did correlate with a right shoulder imbalance in the Lenke1A group. These results suggest that in AIS with a constructive thoracic curve, right shoulder imbalance is an independent risk factor for upper extremity skeletal muscle asymmetry.

Body asymmetries as risk factors for musculoskeletal injuries in dancesport, hip-hop and ballet dancers?

The study aimed to determine the incidence and expression of body asymmetries in dancers of three different dance styles: dancesport (n = 14), hip-hop (n = 21) and ballet (n = 20) and to examine how body asymmetries (muscle strength and power, stability and range of motion) are associated with musculoskeletal injuries occurring over the past 12 months. Cross-sectional and retrospective study. Maximal isometric voluntary contraction was measured for trunk, hip, knee and ankle movements. Participants performed a single leg stance, unilateral landing, weight bearing symmetry, squat and countermovement jump on force platforms. Passive range of motion was measured for hip, knee and ankle with two-arm goniometer or digital inclinometer (hip flexion, extension and rotations). A retrospective questionnaire was used to collect data on musculoskeletal injuries occurring in the last 12 months. Different dance styles were associated with different body asymmetries, including strength asymmetries (hip flexion and external rotation), agonist/antagonist asymmetries (trunk flexion/extension, hip abduction/adduction, ankle dorsi/plantar flexion) and hip adduction and internal rotation range of motion asymmetries. Moreover, strength asymmetries of hip flexion, adduction and abduction/adduction as well as stability asymmetries were associated with the total number of musculoskeletal injuries. The incidence of body asymmetries (> 10%) in dancesport, hip-hop and ballet dancers was confirmed, as well as the association of some asymmetries with self-reported injuries occurring over the last 12 months. The cause-effect relationship should be clarified by further studies.

Comparison of eccentric hamstring strength and asymmetry at return-to-sport after hamstring strain injury among those who did and did not re-injure

ObjectivesThe primary aim of this study was to describe eccentric hamstring strength magnitude and asymmetry at the time of return-to-sport (RTS) after an index hamstring strain injury (HSI) and determine if there were differences in strength asymmetry at RTS between those who did and did not go on to re-injure within 1-month and within 3-months of RTS. DesignCross-sectional study. SettingLaboratory-based. ParticipantsSixty National Collegiate Athletic Association Division I athletes with index HSI. Main Outcome Measures: Maximum hamstring eccentric strength for each limb, total maximum strength summed across limbs, and between-limb asymmetry at the time of RTS following the index HSI, assessed using the NordBord Hamstring Testing System. ResultsOf the 60 index HSIs, 8 (13%), and 11 (18%) re-injuries occurred within 1 and 3-months of RTS, respectively. There were no differences between those who did and did not re-injure in maximum eccentric force of either limb (p-values≥0.52), total force from both limbs (p-values≥0.47), and between limb force asymmetry (p-values≥0.91), regardless if re-injury occurred within 1 or 3-months after RTS. ConclusionsEccentric hamstring strength and asymmetry measured at the time of RTS did not differ between those who did and did not re-injure within 3-months of RTS.

Handgrip strength asymmetry cut points to identify slow gait speed in six low- and middle-income countries: A cross-sectional analysis with 12,669 older adults

BackgroundHandgrip strength (HGS) asymmetry is associated with slow gait speed. Both mark muscle dysfunction, potential risk of falls, and adverse health outcomes. This association was found in older adults from high-income countries, but not yet studied in low- and middle-income countries. Moreover, there is no HGS asymmetry referential to identify the disabling process. Thus, our study aims to verify the association of HGS asymmetry with slowness in older adults from six low- and middle-income countries and to propose cut points to slowness. MethodsA cross-sectional study with data from 12,669 older adults (≥60 years) of the Study on Global Aging and Adult Health (SAGE) conducted in six low- and middle-income countries were analyzed. Based in the difference between upper body sides HGS (asymmetry), participants were categorized in groups as 0.0–10.0% (reference group), 10.1–20.1%, 20.1–30.0% or >30.0%. Slow gait speed was established as <0.59 (men) and <0.51 (women) m/s. Associations of HGS asymmetry with gait speed were ascertained with logistic regression. HGS asymmetry index “[(HGS asymmetry*HGS)/(BMI*Age)]*100” cut points to identify slowness were generated with the ROC curve and Youden index (α = 5%). ResultsCompared to HGS reference group, those with HGS asymmetry of 10.1–20%, 20.1–30.0% and >30.0% had a superior odds for slowness [1.18(CI:1.02,1.42); 1.17(CI: 0.97; 1.44); and 1.21(CI:1.03;1.43), respectively]. HGS asymmetry index cut points to identify slowness were ≤1.14 (women) and ≤1.77 (men). ConclusionsHGS asymmetry association with slowness is present in economically disadvantaged countries. We proposed a new index for impaired muscle function with acceptable sensibility and specificity.

Muscle Asymmetries in the Lower Limbs of Male Soccer Players: Preliminary Findings on the Association between Countermovement Jump and Tensiomyography.

Strength and power asymmetries have been observed in different sports, including soccer. Such asymmetries, as well as the bilateral deficit (BLD), can be assessed during different tasks, static or dynamic, and with different methods and devices, in order to detect the possible different aspects, as well as the association with physical performance and injuries. The aim of this study was to investigate the association between muscle asymmetries and BLD during a countermovement jump (CMJ), and tensiomyography (TMG) parameters and asymmetries, in the lower limbs of male soccer players. A total of 23 male soccer players (18 ± 4 years) were recruited. Bilateral and unilateral CMJs were performed, and peak power (W) and height (cm) were obtained. TMG was performed on different muscles of the lower limbs, and lateral and functional symmetries were obtained. Playing position and history of injuries were collected. CMJ inter-limb symmetry was found to significantly correlate with biceps femoris (r = 0.574, p = 0.004) and soleus (r = 0.437, p = 0.037) lateral symmetry. Players in central roles presented significantly worse functional symmetry scores of the knee than defense players (-17.5%, 95% CI -31.2--3.9; p = 0.10). Participants reporting a history of injury at the ankle were characterized by significantly lower functional symmetry in both the dominant (43%, 39.5-48.0 vs. 74.5%, 46.5-89.3, p = 0.019) and non-dominant (45%, 42.5-46.0 vs. 81.0%, 45.8-90.3, p = 0.024) ankle. Findings from this preliminary study suggest an association between lower-limb muscle asymmetries during a dynamic task, such as jumping, and muscle contractile properties evaluated with TMG; moreover, functional asymmetries may be present after ankle injuries. Future studies in larger samples should evaluate the presence of such asymmetries as predictors or characteristics of different muscular and joint injuries.

A 2-year prospective randomized controlled trial investigating an accelerated rehabilitation pathway after double-bundle, remnant sparing anterior cruciate ligament reconstruction (ACLR)

Introduction: Anterior cruciate ligament reconstruction (ACLR) is common. Insufficient quadriceps strength and functional hop asymmetry are associated with an increased re-injury risk after ACLR upon return to sport (RTS). This study sought to investigate whether an accelerated rehabilitation pathway after ACLR with a hamstring autograft could enhance strength and functional symmetry after ACLR, without affecting graft laxity and/or re-injury.