Muscle Strength Deficits Research Articles

Limitations in Maximum Intensity Front Crawl in Swimmers with Down Syndrome

Individuals with Down Syndrome exhibit deficits in muscle strength and cardiovascular adaptation, which limit athletic performance. We compared a maximum-intensity 50 m front crawl test between competitive male swimmers with Down Syndrome (SDS; n = 11; 26.5 ± 5.6 years; m ± SD) and a control group of swimmers (CNT; n = 11; 27.1 ± 4.0 years) with similar training routines (about 5 h/week). Wearable sternal sensors measured their heart rate and 3D accelerometry. The regularity index Sample Entropy (SampEn) was calculated using the X component of acceleration. The total times (SDS: 58.91 ± 13.68 s; CNT: 32.55 ± 3.70 s) and stroke counts (SDS: 66.1 ± 9.6; CNT: 51.4 ± 7.4) were significantly higher in the SDS group (p < 0.01). The heart rate was lower in the SDS group during immediate (SDS: 129 ± 15 bpm; CNT: 172 ± 11 bpm) and delayed recovery (30 s, SDS: 104 ± 23 bpm; CNT: 145 ± 21 bpm; 60 s, SDS: 79 ± 27 bpm; CNT: 114 ± 27 bpm) (p < 0.01 for all the comparisons). The SampEn of sternal acceleration showed no differences between the groups and between 0–25 m and 25–50 m. Body pitch correlated strongly with performance in the SDSs (R2 = 0.632, p < 0.01), but during the first 25 m only. The high-intensity front crawl performances differed between the SDS and CNT athletes in terms of time, biomechanics, and training adaptation, suggesting the need for tailored training to improve swimming efficiency in SDSs.

Longitudinal trajectories of muscle strength deficits in growing boys with Duchenne muscular dystrophy

Longitudinal trajectories of muscle strength deficits in growing boys with Duchenne muscular dystrophy

Identifying Deficits in Hip and Knee Muscle Strength on the Surgical and Nonsurgical Sides in Women up to 12Months After Total Hip Arthroplasty.

Regaining hip and knee muscle strength is important after total hip arthroplasty (THA). However, it is unclear if muscles other than those of the operated hip also lose strength. This study aimed to identify deficits in hip and knee strength on the surgical and nonsurgical sides in female patients up to 12months after THA. Participants were 91 female patients who had hip osteoarthritis and underwent unilateral THA. Forty-six community-dwelling women who were asymptomatic were selected as control participants. Patients with locomotor disorders or postsurgical complications were excluded. Maximal isometric strength of the hip flexors, extensors, and abductors and knee extensors and flexors on the surgical and nonsurgical sides were measured before THA and 3, 6, and 12months thereafter. Twelve months after THA, hip flexion, extension, and abduction strength on the surgical side were 84.6%, 83.5%, and 76.2%, respectively, of those in individuals who were asymptomatic; at the same time point, those on the nonsurgical side were 94.8%, 83.9%, and 79.4%, respectively. Knee extension strength on the surgical side was 89.3% of that in individuals who were asymptomatic. Compared to individuals who were asymptomatic, nearly all muscles showed significantly lower strength on both sides up to 6months after THA. At 12months after THA, hip and knee strength on both the surgical and nonsurgical sides did not recover to the level observed in individuals who were asymptomatic. In particular, hip abductor strength on the surgical and nonsurgical sides were 76% and 79%, respectively, of that in individuals who were asymptomatic. At 12months after THA, hip and knee strength on the surgical and nonsurgical sides did not recover to the level observed in individuals who were asymptomatic, suggesting that the nonsurgical side may be inappropriate as a control to assess strength recovery on the surgical side.

Effect of Limb Dominance on Chronic Ankle Instability: Does It Matter?

Our study aimed to examine preoperative differences in strength and balance between dominant foot (DF) and nondominant foot (non-DF) of individuals undergoing ligament stabilization surgery in the general population. Patients with records of preoperative evaluation, including isokinetic dynamometric strength evaluation, Y-balance test (YBT), and Foot and Ankle Outcome Score (FAOS), were included in the study. The DF was the preferred leg for accurately kicking a ball through a goal. Statistical analysis determined the differences between DF and non-DF and the correlations between muscle strength, balance, and FAOS. There was no statistically significant difference between DF and non-DF regarding evertor and invertor muscle strength (p=0.082-0.951). The YBT revealed no significant difference between the two groups (p=0.082-0.951). There was a significant correlation between the evertor peak torque and total work deficits at 30°/s (p=0.022), as well as the evertor peak torque deficit at 120°/s (p=0.048). No significant differences in muscle strength and balance were found between DF and non-DF in nonathletes with chronic ankle instability. Peroneal muscle strength deficit was associated with functional impairment. Tailored interventions are needed to address limb dominance and muscle strength deficits in CAI management.

Risk of low bone mineral density in young pediatric cancer survivors with sarcopenia.

10070 Background: Required treatments to cure pediatric cancer at such a young age increase the risk of later health-related complications. Early exposure to DNA damaging agents, during a vital period of active skeletal growth, interferes with accrual of bone mass. Treatments not only impair bone health, but also affect skeletal muscle function and mass. Long-term pediatric cancer survivors present these limitations due to myofibrillary atrophy caused by degradation of myosin heavy chain and decrease in myosin synthesis death. Muscle weakness (both muscle strength deficits and low lean mass hereafter referred to as sarcopenia) and low areal bone mineral density (aBMD) have been observed to coexist in adult survivors of paediatric cancer. However, in young pediatric cancers survivors, associations between sarcopenia and low aBMD are not well described. Therefore, this study aimed to examine the risk of low aBMD in young pediatric cancer survivors with sarcopenia confirmed/probable, compared to not having sarcopenia. Methods: This cross-sectional study included 116 pediatric cancer survivors (12.1±3.3 years old; 42% female) enrolled on a randomized controlled trial designed to improve bone health (iBoneFIT project). Handgrip strength was used to assessed muscle strength. Dual-energy X-ray absorptiometry estimated aBMD (g/cm2) at the total body (less head), lumbar spine, total hip and femoral neck, and appendicular lean mass index (ALMI, kg/m2). Sarcopenia status was determined using age and sex specific international reference data from a healthy population. “No sarcopenia” was defined when muscle strength was >decile 2. “Sarcopenia probable” was defined when muscle strength was ≤decile 2 and ALMI Z-score was > -1.5 standard deviation (SD). “Sarcopenia confirmed” was defined when muscle strength was ≤decile 2 and ALMI Z-score ≤-1.5 SD. Logistic regression, adjusted for time from treatment completion and radiation exposure, was used to evaluate the risk of low aBMD (age-, sex- and race-specific aBMD Z-score < -1.0) by sarcopenia status. Results: More than one-third of survivors met criteria for sarcopenia confirmed (37.9%); 19.0% met criteria for sarcopenia probable. Survivors with sarcopenia confirmed had higher risk of low aBMD at the total body (odd ratio [OR]: 6.91, 95% confidence interval [CI]: 2.31-24.15), total hip (OR: 2.98, 95% CI: 1.02-9.54) and femoral neck (OR: 4.72, 95% CI: 1.72-14.19) than those without sarcopenia. Survivors with sarcopenia probable had higher risk of having low aBMD only at the total body (OR: 4.13, 95% CI: 1.04-17.60) than those without sarcopenia. Conclusions: Over one-third of young paediatric cancer survivors presented sarcopenia confirmed with higher risk of low aBMD. These findings suggest that interventions to mitigate osteosarcopenia in this population should be implemented at early stages after treatment completion.

Resistance exercise training to improve post-operative rehabilitation in knee arthroplasty patients: A narrative review.

Knee osteoarthritis is associated with deficits in muscle strength, muscle mass, and physical functioning. These muscle-related deficits are acutely exacerbated following total knee arthroplasty (TKA) and persist long after surgery, despite the application of standardized rehabilitation programs that include physical/functional training. Resistance exercise training (RET) has been shown to be a highly effective strategy to improve muscle-related outcomes in healthy as well as clinical populations. However, the use of RET in traditional rehabilitation programs after TKA is limited. In this narrative review, we provide an updated view on whether adding RET to the standard rehabilitation (SR) in the recovery period (up to 1year) after TKA leads to greater improvements in muscle-related outcomes when compared to SR alone. Overall, research findings clearly indicate that both muscle strength and muscle mass can be improved to a greater extent with RET-based rehabilitation compared to SR. Additionally, measures of physical functioning that rely on quadriceps strength and balance (e.g., stair climbing, chair standing, etc.) also appear to benefit more from a RET-based program compared to SR, especially in patients with low levels of physical functioning. Importantly though, for RET to be optimally effective, it should be performed at 70%-80% of the one-repetition maximum, with 3-4 sets per exercise, with a minimum of 3 times per week for 8weeks. Based upon this narrative review, we recommend that such high-intensity progressive RET should be incorporated into standard programs during rehabilitation after TKA.

Single Nuclear Analyses Reveal Compromised Integrity of Neuromuscular Junction Myonuclei Following Joint Injury

The neuromuscular junction is an essential structure that links electrical signals from the nervous system to contraction of skeletal muscle. The post synaptic region of a muscle cell is maintained by a subset of specialized myonuclei responsible for clustering of post synaptic structural proteins and acetylcholine receptors. Disruptions in the transcriptional program of these myonuclei may result in ineffective myofiber recruitment, slowed force generation, and muscle weakness. We have shown that traumatic joint injury results in protracted deficits in muscle strength and power, but the peripheral mechanistic underpinnings remain unclear. Phenotypically, muscle pathology occurring after traumatic joint injury resembles that of neuromuscular destabilization, yet molecularly, this remains uninvestigated. Therefore, we hypothesize that disruption of neuromuscular regulatory gene programs and destabilization of the neuromuscular junction following joint injury will result in rapid muscle functional deficits. Human muscle biopsies were obtained from the vastus lateralis of anterior cruciate ligament (ACL) injured and healthy limbs of 26 participants. Injured biopsies were taken before and 7 days following reconstruction surgery. Bulk tissue RNA-seq analysis was performed on all participants and single-nucleus RNAseq (snRNAseq) was performed on a subset of participants. Briefly, for snRNAseq, muscle was dounce homogenized, filtered, and nuclei isolated via fluorescent activated cell sorting. Following sequencing, CellRanger output files containing count matrices were filtered, and analyzed using Partek Flow and Seurat. Biopsy sections were processed for histochemistry to analyze fiber size and motor end plate innervation. All participants underwent strength testing on a biodex to assess isometric quadriceps torque and rate of torque development. RNA sequencing displayed >3 fold upregulation of CHRNA1 (P< 0.001) after injury alone and >18 fold upregulation 7 days following reconstruction surgery (P< 0.001). This was accompanied by a host of other neuromuscular regulatory genes including HDAC4 (P< 0.001), GDNF (P< 0.001), and RUNX1 (P< 0.001). Single nucleus sequencing revealed a complete disappearance of neuromuscular junction regulatory myonuclei following reconstruction surgery coupled with delocalization of acetylcholine receptor expression. These findings were confirmed with fluorescent in situ hybridization of CHRNA1 RNA on biopsy sections. Functionally, CHRNA1 RNA expression strongly correlates with deficits in rate of torque development following injury (R^2 = 0.85, P< 0.001). Our results display rapid remodeling of the postsynaptic neuromuscular junction following joint injury that underscores sustained deficits in strength and power. Interventions targeting the preservation of peripheral innervation may be warranted to enhance outcomes following joint injury. R01AR072061. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

HDAC4 Genomic Methylation and Subsequent DNA Binding Following Joint Injury Confers a Sustained Epigenetic Memory of Disrupted Muscle Plasticity

Joint injury is associated with protracted atrophy and weakness that poorly recovers; our objective was to define molecular effectors of lost muscle size, strength, and plasticity following joint injury. We hypothesized that epigenetic imprinting of joint injury in muscle impairs muscle plasticity and contributes to poor functional recovery following surgical repair. We recruited a total of sixteen ACL-injured participants from whom we obtained vastus lateralis muscle biopsies Pre-, 7-days post-, and 4-months post- reconstruction surgery (Sx) and strength measures up to 6-months post-Sx. We performed immunohistochemistry, RNA-seq, reduced representation bisulfite sequencing (RRBS), and HDAC4 chromatin immunoprecipitation sequencing (HDAC4 ChIP-seq) to determine the impact of epigenetics and gene expression on histological profiles, muscle size and muscle strength following injury. Binding and Expression Target Analysis (BETA) of DNA methylation revealed a conserved 985bp regulatory genomic region that was differentially methylated upstream of the HDAC4 promoter. We observed 108 (Pre-Sx), 111 (7d post-Sx), and 110 (4-months post-Sx) differentially methylated promoter sites of which 95 sites were common across all timepoints in the injured limb. Additionally, we observed 1293 differentially methylated intragenic sites within the HDAC4 locus that were also common across all timepoints following injury. Altered HDAC4 methylation was associated with a 2.2 and 4.3 fold change in HDAC4 transcript abundance Pre-Sx and 7d post-Sx, respectively (FDR < 0.05). Notably, HDAC4 binding to critical contractile genes coincided with their downregulation 7d post-Sx (Log2 fold change: ACTA1: -2.02; CKM: -0.97; ATP2A1: -2.34; HOMER2: -1.09; all FDR<0.05). Altered transcript abundance of these genes coincided with lower mean muscle fiber cross-sectional area in the injured limb compared to Healthy (Healthy: 4845 ± 213.4μm2; pre-Sx: 4313 ± 190.6μm2, p<0.05; 7d post-Sx: 3685 ± 228.1μm2, p<0.05; 4-months post-Sx: 3422 ± 142.8μm2, p<0.05) and lower peak torque compared to Healthy (Healthy: 174.8 ± 10.72nm; pre-Sx: 135.2 ± 10.19nm, p<0.05; 4-months post-Sx: 82.64 ± 6.80nm, p<0.05; 6-months post-Sx: 105.9 ± 8.26nm, p<0.05) that was sustained throughout follow-up. Our results suggest that joint injury confers HDAC4 promoter-proximal and intragenic epigenetic imprinting by DNA methylation that increases HDAC4 transcript abundance and HDAC4-DNA binding to represses expression of genes regulating muscle contractile function. This HDAC4 gene regulatory program likely contributes to prolonged deficits in muscle size and strength following joint injury. This work was supported by NIH-NIAMS R01 AR072061. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

No sign of weakness: a systematic review and meta-analysis of hip and calf muscle strength after anterior cruciate ligament injury

ObjectiveWe aimed to determine hip and lower-leg muscle strength in people after ACL injury compared with an uninjured control group (between people) and the uninjured contralateral limb (between limbs).DesignSystematic review...

Let's get physical: Aerobic capacity, muscle strength, and muscle endurance after pediatric heart transplantation.

Pediatric heart (HTx) and kidney transplant (KTx) recipients may have lower physical fitness than healthy children. This study sought to quantify fitness levels in transplant recipients, investigate associations to clinical factors and quality of life, and identify whether a quick, simple wall-sit test is feasible as a surrogate for overall fitness for longitudinal assessment. Aerobic capacity (6-min walk test, 6MWT), normalized muscle strength, muscle endurance, physical activity questionnaire (PAQ), and quality of life (PedsQL™) were prospectively assessed in transplanted children and matched healthy controls. Twenty-two HTx were compared to 20 controls and 6 KTx. 6MWT %predicted was shorter in HTx (87.2 [69.9-118.6] %) than controls (99.9 [80.4-120] %), but similar to KTx (90.3 [78.6-115] %). Muscle strength was lower in HTx deltoids (6.15 [4.35-11.3] kg/m2) and KTx quadriceps (9.27 [8.65-19.1] kg/m2) versus controls. Similarly, muscle endurance was lower in HTx push-ups (28.6 [0-250] %predicted), KTx push-ups (8.35 [0-150] %predicted), HTx curl-ups (115 [0-450] %predicted), and KTx wall-sit time (18.5 [10.0-54.0] s) than controls. In contrast to HTx with only 9%, all KTx were receiving steroid therapy. The wall-sit test significantly correlated with other fitness parameters (normalized quadriceps strength R = .31, #push-ups R = .39, and #curl-ups R = .43) and PedsQL™ (R = .36). Compared to controls, pediatric HTx and KTx have similarly lower aerobic capacity, but different deficits in muscle strength, likely related to steroid therapy in KTx. The convenient wall-sit test correlates with fitness and reported quality of life, and thus could be a useful easy routine for longitudinal assessment.

Muscle strength deficits are associated with low bone mineral density in young pediatric cancer survivors: The iBoneFIT project

BackgroundPediatric cancer survivors are at increased risk of muscle weakness and low areal bone mineral density (aBMD). However, the prevalence of muscle strength deficits is not well documented, and the associations of muscle strength with aBMD are unknown in this population. Therefore, this study aimed to investigate the prevalence of upper- and lower-body muscle strength deficits and to examine the associations of upper- and lower-body muscle strength with age-, sex, and race-specific aBMD Z-scores at the total body, total hip, femoral neck, and lumbar spine. MethodsThis cross-sectional study included 116 pediatric cancer survivors (12.1 ± 3.3 years old, mean ± SD; 42.2% female). Upper- and lower-body muscle strength were assessed by handgrip and standing long jump test, respectively. Dual‑energy X‑ray absorptiometry was used to measure aBMD (g/cm2). Associations between muscle strength and aBMD were evaluated in multivariable linear regression models. Logistic regression was used to evaluate the contribution of muscle strength (1-decile lower) to the odds of having low aBMD (Z-score ≤ 1.0). All analyses were adjusted for time from treatment completion, radiotherapy exposure, and body mass index. ResultsMore than one-half of survivors were within the 2 lowest deciles for upper- (56.9%) and lower- body muscle strength (60.0%) in comparison to age- and sex-specific reference values. Muscle strength deficits were associated with lower aBMD Z-scores at all sites (B = 0.133–0.258, p = 0.001–0.032). Each 1-decile lower in upper-body muscle strength was associated with 30%–95% higher odds of having low aBMD Z-scores at all sites. Each 1-decile lower in lower-body muscle strength was associated with 35%–70% higher odds of having low aBMD Z-scores at total body, total hip, and femoral neck. ConclusionMuscle strength deficits are prevalent in young pediatric cancer survivors, and such deficits are associated with lower aBMD Z-scores at all sites. These results suggest that interventions designed to improve muscle strength in this vulnerable population may have the added benefit of improving aBMD.

The optimized tourniquet versus no tourniquet in total knee arthroplasty. Analysis of muscle injury, functional recovery, and knee strength

BackgroundTourniquet is widely used in total knee replacement surgery because it reduces intraoperative hemorrhage and provides a comfortable surgical area for the surgeon. It's possible that its use could lead to impaired postoperative functional and motor recovery, as well as local and systemic complications. Our goal was to compare the outcomes of total knee replacement without ischemia using an optimized protocol, consisting of tourniquet inflation before skin incision and deflation after cementing, with a pressure of one hundred millimeters above systolic blood pressure and without postoperative articular suction drains.). We believed that tourniquet effectively would result in no additional muscle damage and no functional or knee strength impairment compared to no tourniquet. MethodsIn a prospective and randomized study, 60 patients with osteoarthritis were evaluated for total knee replacement, divided in two groups: 'without tourniquet' and 'optimized tourniquet'. Outcomes were mean creatine phosphokinase levels, Knee Society Score and knee isokinetic strength. Data were considered significant when p < 0.05. ResultsCreatine phosphokinase levels and functional score were similar between groups. There were no differences between groups regarding knee extension strength on the operated limbs, although the knee flexors' peak torque in the operated limb in the optimized tourniquet group was significantly higher at 6 months relative to preoperative and 3 months assessments. ConclusionsThe optimized tourniquet protocol use in total knee replacement combines the benefits of tourniquet use without compromising functional recovery and without additional muscle damage and strength deficits compared to surgery without its use.

Exploring the Relationship between Muscular Strength, Flexibility, and mSEBT Test Performance in Saudi Arabian Women

Saudi females exhibit a higher susceptibility to musculoskeletal disorders (MSD), particularly impacting balance, in comparison to their male counterparts. The current study was aimed at determining the association between the modified Star Excursion Balancing Test (mSEBT) score and the muscular strength and flexibility of the lower-extremity muscles among a group of young healthy Saudi females. The mSEBT assessed balance, complemented by measurements of lower-extremity muscle strength and flexibility. Statistical analysis, utilizing SPSS software (version 26.0), with a significance level of p &lt; 0.05, unveiled valuable insights. Results indicate a moderate positive correlation between hip flexor strength and reach distance, notably in the anterior and posteromedial directions. Conversely, no statistically significant associations emerged between hip extensor, hip abductor, or knee extensor strength and reach distances across all directions. Furthermore, there were weak negative correlations between hip flexion angle (assessed via the Thomas test) and reach distances, primarily within the anterior direction. Interestingly, the sit-and-reach flexibility test demonstrated no significant correlations with reach distances. These findings underscore the role of hip flexor strength and flexibility in influencing mSEBT performance in young, healthy Saudi females. This study advocates for the incorporation of the mSEBT as a diagnostic and therapeutic tool for identifying individuals with deficits in lower extremity muscle strength and flexibility.

Deficits in muscle strength are not seen following recovery from augmented primary repair of anterior cruciate ligament tears

ObjectivesAnterior cruciate ligament (ACL) repair for proximal tears, where the ligament is re-attached and augmented with suture tape, can negate the need for graft harvest, thereby maintaining native anatomy. Autograft harvest has been associated with persistent deficits in lower limb muscle strength after recovery from ACL reconstruction. The aim of this study is to compare lower limb muscle strength following ACL repair and reconstruction. MethodsNineteen ACL repair patients augmented with suture tape and nineteen ipsilateral semitendinosus-gracilis autograft ACL reconstruction patients (both mean 4 years postoperatively) were recruited, along with twenty healthy volunteers. Patient-reported outcome measures (PROMs) were obtained using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Lysholm, and Tegner scores. Maximal isometric quadriceps and hamstring strength at 90° knee flexion were measured using a fixed Myometer after a warm-up and three maximal-effort contractions. ResultsMean hamstring strength of the reconstructed legs was lower than that of healthy volunteers by 0.29 Nm/kg. The hamstring strength ratio of the operated side to the uninjured side was greater in the repair (95% ​± ​13) than in the reconstruction (81% ​± ​18) group. There were no statistically significant differences between sides for quadriceps peak torque or for hamstrings in the volunteer or repair group. PROMs scores for the reconstruction group were significantly lower than volunteers across all domains and lower than repair for KOOS activities of daily living and Lysholm scores. ConclusionHamstring weakness seen following ACL reconstruction is not evident following ACL repair with suture tape augmentation. Strength asymmetry could contribute to re-injury risk and influence functional performance, while altered loads affect knee biomechanics and may lead to osteoarthritis progression. The absence of these deficits in the repair group demonstrates a potential benefit of this technique when used in appropriate patients. Level of evidenceII.

The correlation between chronic ankle instability and strength deficit of the hip and knee musculature: a review of the literature

Introduction: The aim of the present study is to analyze the correlation between people that suffer from chronic ankle instability and muscle strength deficits of the proximal joints of the lower limb, which are the hip and knee. Methods: The narrative review was conducted on MEDLINE using the selected keywords to build the search string. After inclusion and exclusion criteria were applied, the articles were independently screened by two authors reading the titles and abstracts or full articles. The quality assessment was conducted using the NIH quality assessment tool for observational cohort and cross-sectional studies, the methodological index for non-randomized studies scale, the risk-of-bias tool for non-randomized trials, and the Critical Appraisal Skills Programme checklist. Result: From 506 papers originally identified through database search, six studies were finally selected. The quality score was medium to low in all studies according to selected tool. Major of the included studies underlined that the lower limb strength deficits represent a key factor in the rehabilitation path in patients with chronic ankle instability (CAI) and, in addition to predictable ankle’s muscle impairments, hip strength was a significant weakness in performance evaluation in this type of patients. Conclusion: It’s not possible to confirm to our knowledge a strictly significant correlation between strength deficit of hip and knee, when appreciated. These results, however, might suggest another time that the difference between people who suffer from CAI and coper is the rehabilitation program that patients follow after an injury. Keywords: Strength, Lower Extremity, Ankle Injury, Joint Instability

Síndrome de Parsonage Turner em Nadadora de Elite

Parsonage-Turner syndrome (PTS) is a rare disorder characterized by sudden shoulder pain followed by neurologic deficits. The exact etiology remains unclear, although a genetic predisposition is suspected in association with a trigger. The diagnosis is made clinically, supported by electrodiagnostic and imaging studies. There is no specific treatment, and the prognosis is generally favorable. This case-report relates to an 18-year-old competitive swimmer who developed left shoulder pain after a flu-like illness, resulting in a deficit of muscle strength and sensitivity. She was diagnosed at PTS and treated with corticosteroids and an individualized rehabilitation program, resulting in resolution of the condition within 6 months. Early diagnosis and treatment are important to prevent long-term sequelae and allow a quicker return to sports activities.

Abscisic acid ameliorates motor disabilities in 6-OHDA-induced mice model of Parkinson's disease

Parkinson's disease (PD) is characterized by a myriad of symptoms, encompassing both motor disabilities and cognitive impairments. Recent research has shown that abscisic acid (ABA) is a phytohormone found in various brain regions of several mammals and exhibits neuroprotective properties. To investigate the effects of ABA on cognitive and motor disorders, a mouse model of PD was utilized. The administration of 6-hydroxydopamine (6-OHDA) to the lateral ventricles was conducted, with ABA (10 and 15 μg/mouse, i. c.v.) being administered for one week after the 6-OHDA injection for 4 days. Motor and cognitive performance were evaluated through the use of open field, rotarod, wire grip, and shuttle box tests. The results indicated that cognitive function and motor disorders were significantly impaired in 6-OHDA-treated animals. However, in mice treated with 6-OHDA, ABA (15 μg/mouse) significantly reversed balance and muscle strength deficits. It should be noted that the administration of ABA did not significantly improve cognitive impairment or rearing in Parkinsonism mice. Therefore, the findings suggest that ABA plays a crucial role in protecting mice from motor disabilities caused by 6-OHDA.

The effect of strengthening exercise on the balance of athletes with chronic ankle instability: a literature review

Background: Repetitive ankle sprains can cause chronic ankle instability. More than 40% of athletes experience repeated ankle sprains and tend to be indifferent to these conditions, causing a decrease in ability when exercising or competing due to deficits in lower leg muscle strength, especially ankle propulsion, neuromuscular, proprioceptive, and postural control.&#x0D; Objective: to determine the effect of strength exercise on athletes with chronic instability ankle conditions.&#x0D; Method: the method used is a literature review or reviewing several articles that have been published.&#x0D; Results: The seven journals discussed show that strength exercise can improve the balance of athletes with chronic stability ankle conditions, and there are also several combinations of using tools such as resistance bands and blood flow restriction cuffs that make strength exercise more effective in improving the balance of athletes with chronic stability ankle conditions.&#x0D; Conclusion: There is an effect of strengthening exercises on the balance of athletes with chronic ankle instability.

Hip rotation muscle strength is implicated in the progression of early post-traumatic osteoarthritis: A longitudinal evaluation up to 5 years following ACL reconstruction

IntroductionFollowing ACL reconstruction (ACLR), deficits in hip muscle strength and relationships to future outcomes are unknown. Methods111 participants one year after ACLR, completed hip external rotation (ER) and internal rotation (IR) strength assessment. At 1 (n = 111) and 5 (n = 74) years post-ACLR, participants completed a battery of functional, symptomatic (Knee Osteoarthritis Outcome Score (KOOS)) and structural assessments (radiography, magnetic resonance imaging (MRI)). Cartilage health of the patellofemoral and tibiofemoral compartments was assessed with the semiquantitative MRI Osteoarthritis Knee Score. Hip rotation strength was compared between-limbs, and relationships between hip strength at 1 year and functional, symptomatic and cartilage outcomes at 1 and 5 years were investigated with regression models. ResultsThe index (ACLR) limb had weaker hip ER (but not IR) strength compared to the contralateral side (standardised mean difference ER = −0.33 (95%CI -0.60, −0.07; IR = −0.11 (95%CI -0.37, 0.15). Greater hip ER and IR strength was associated with superior function at 1 and 5 years, and better KOOS-Patellofemoral symptoms at 5 years. Greater hip ER strength was associated with lower odds of worsening tibiofemoral cartilage lesions at 5 years (odds ratio 0.01, 95%CI 0.00, 0.41). ConclusionHip rotation strength may play a role in worsening function, symptoms and cartilage health after ACLR.

Effect of hamstring injuries on athlete’s season best performance at return-to-sport phase of rehabilitation: survey of track runners in high altitude training camps in Kenya

Background: Hamstring injuries amongst runners are some of the most prevalent sports injuries. However, the actual impact of these injuries on athlete’s best performance pre-injury is unknown. The objective of this study was to assess the impact of hamstring injury on athletes’ performance at return to sport phase of rehabilitation amongst track runners in Western Kenya. Methods: Observational longitudinal study utilizing quantitative methods were used. The study setting was in the high-altitude western Kenya regions with accredited training camps. The functional assessment scale for hamstring injuries (FASH) was used to screen injuries and an observational checklist to record the conventional rehabilitation strategies. A moderator effect analysis for the variables was conducted followed by a multi-linear regression analysis to establish the effect of injury on performance. The results were presented in summary tables and graphs. Results: A total of 221 (53% response rate) athletes participated in the study as having a hamstring injury. The study found that athletes took more time after injury compared to their personal best and before injury time records. The average best time for full marathoners was 2:17:19.46 (SD±0:10:54.804), before injury 2:18:05.36 (SD±0:11:06.879) and after injury 2:22:12.02 (SD±0:12:45.174). Conclusions: The study concludes that the prevalence of hamstring injuries among endurance runners in Kenya’s Rift Valley region is still so high. The paper recommends emphasis on extensive strength training before return to sport to address deficits in muscle and eccentric strength on return to sport.