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CONTEXT:: Quadriceps function is a significant contributor to knee joint health that is influenced by central and peripheral factors, especially after anterior cruciate ligament reconstruction (ACLR). OBJECTIVE:: To assess differences of unilateral quadriceps isometric strength and activation between the involved limb and contralateral limb of individuals with ACLR and healthy controls. DATA SOURCES:: Web of Science, SportDISCUS, PubMed, CINAHL, and the Cochrane Database were all used during the search. STUDY SELECTION:: A total of 2024 studies were reviewed. Twenty-eight studies including individuals with a unilateral history of ACLR, isometric knee extension strength normalized to body mass, and quadriceps activation measured by central activation ratios (CARs) through a superimposed burst technique were identified for meta-analysis. The methodological quality of relevant articles was assessed using a modified Downs and Black scale. Results of methodological quality assessment ranged from low to high quality (low, n = 10; moderate, n = 8; high, n = 10). STUDY DESIGN:: Meta-analysis. LEVEL OF EVIDENCE:: Level 2. DATA EXTRACTION:: Means, standard deviations, and sample sizes were extracted from articles, and magnitude of between-limb and between-group differences were evaluated using a random-effects model meta-analysis approach to calculate combined pooled effect sizes (ESs) and 95% CIs. ESs were classified as weak ( d < 0.19), small ( d = 0.20-0.49), moderate ( d = 0.50-0.79), or large ( d > 0.80). RESULTS:: The involved limb of individuals with ACLR displayed lower knee extension strength compared with the contralateral limb (ES, -0.78; lower bound [LB], -0.99; upper bound [UB], -0.58) and healthy controls (ES, -0.76; LB, -0.98; UB, -0.53). The involved limb displayed a lower CAR compared with healthy controls (ES, -0.84; LB, -1.18; UB, -0.50) but not compared with the contralateral limb (ES, -0.15; LB, -0.37; UB, 0.07). The ACLR contralateral limb displayed a lower CAR (ES, -0.73; LB, -1.39; UB, -0.07) compared with healthy control limbs but similar knee extension strength (ES, -0.24; LB, -0.68; UB, -0.19). CONCLUSION:: Individuals with ACLR have bilateral CAR deficits and involved limb strength deficits that persist years after surgery. Deficits in quadriceps function may have meaningful implications for patient-reported and objective outcomes, risk of reinjury, and long-term joint health after ACLR.

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Lesiones del Ligamento Cruzado Anterior/cirugía , Reconstrucción del Ligamento Cruzado Anterior , Fuerza Muscular , Músculo Cuádriceps/fisiología , Lesiones del Ligamento Cruzado Anterior/fisiopatología , Femenino , Humanos , Contracción Isométrica , Rodilla/fisiología , Masculino , Factores Sexuales , Torque

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BACKGROUND: Physical impairment or frailty due to sarcopaenia is common in patients with chronic kidney disease and those receiving dialysis. This study examined the association between muscle weakness and kidney function in Japanese patients with chronic kidney disease. METHODS: A total of 23 stable outpatients were enrolled in the study. Several indices were used to assess muscle function; hand grip strength, isometric knee extension strength, Timed Up and Go test (TUG), and the short physical performance battery. The relationships between these indices and estimated glomerular filtration rate (eGFR) as a measure of kidney function were analysed statistically. RESULTS: Patients' characteristics were as follows: mean age 73.9 years (standard deviation (SD) 13); 12 males, 11 females; body mass index (BMI) 22.5 kg/m2 (SD 3.2); serum creatinine (sCr) 4.6 mg/ dl (SD 3.7); estimated glomerular filtration rate (eGFR) 19.1 ml/min (SD 16). Their physical performance indices were: hand grip strength 20.8 kg (SD 7.9); isometric knee extension strength 19.1 kgf/kg (SD 10.6); TUG 14.9 s (SD 6.0); and short physical performance battery score 7.0 (SD 4.3). Multiple regression analysis adjusted for age revealed significant associations between isometric knee extension strength/body weight and eGFR (F [2,19] = 8.38, p = 0.002) and TUG and eGFR (F=4.98 [2,18], p = 0.02). CONCLUSION: Deterioration in muscle function or maintenance of posture is associated with chronic kidney disease.

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PURPOSE: To investigate the effects of graft source, time since surgery, age, and sex on unilateral and symmetry-based measures of knee extension strength among individuals with ACL reconstruction (ACLR). METHODS: Three hundred and eight individuals aged 13-40 years old with primary, unilateral ACLR in the last 60 months were enrolled in this multi-site clinical measurement study. Participants completed bilateral knee extension maximal voluntary isometric contraction (MVIC) torque assessments which were normalized to body mass (Nm/kg) and limb symmetry indices (LSI) were calculated. The effects of graft source (patellar tendon autograft; hamstring tendon autograft), time since surgery (≤ 12 months; >12 mo.), age (≤ 18 years; >18 years), and sex were evaluated using separate ANCOVAs. RESULTS: A significant interaction was present between time since surgery and graft source for LSI (P = 0.01) as participants with patellar tendon autografts ≤ 12 months post-ACLR experienced the greatest asymmetry (LSI = 69.2 ± 24.5%). Significant interactions were present between time since surgery and sex for involved limb (P = 0.01) and uninvolved limb MVIC torque (P = 0.05) with females ≤ 12 months post-ACLR being weakest (involved MVIC = 1.81 ± 0.70 N m/kg; uninvolved MVIC = 2.40 ± 0.68 N m/kg). Participants ≤ 18-year-old displayed weaker involved limb (P < 0.001) and contralateral limb (P < 0.001) MVIC torque as compared to participants > 18-year-old during the first year after ACLR. CONCLUSIONS: Graft source, sex, age, and time since surgery effect quadriceps strength and symmetry after ACLR. Surgical and demographic factors should be considered when developing treatment approaches to optimize quadriceps function prior to re-integration into pre-injury levels of physical activity. LEVEL OF EVIDENCE: IV.

Asunto(s)

Reconstrucción del Ligamento Cruzado Anterior , Fuerza Muscular/fisiología , Músculo Cuádriceps/fisiología , Adolescente , Adulto , Factores de Edad , Femenino , Humanos , Masculino , Ligamento Rotuliano/trasplante , Factores Sexuales , Tendones/trasplante , Factores de Tiempo , Adulto Joven

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[Purpose] The purpose of this study was to evaluate the lower limb muscle strength of the community-dwelling elderly, with or without cognitive decline, using isometric knee extension strength (IKES) and the 30-second chair stand test (CS-30). [Subjects] A total of 306 community-dwelling elderly participated in this study. Assessment items were the CS-30, IKES, Mini-Mental State Examination (MMSE), and Trail-Making Test Part A (TMT-A). [Methods] Participants were divided into three groups according to their MMSE score: cognitive impairment (MMSE ≤ 24), cognitive decline (MMSE 25 to 27), and normal (MMSE ≥ 28). We compared IKES and CS-30 among the three groups. [Results] IKES was not significantly different among the three groups. However, the CS-30 was significantly different among the three groups. Upon further analysis the CS-30 score of each group, when adjusted for age and TMT-A, did not indicate a significant difference. [Conclusion] These results suggest that the lower limb muscle strength of the elderly does not differ with cognitive decline. Moreover, we suggest that when using the CS-30 score as an indicator of lower limb muscle strength attentional function should be taken into account.

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This study examined age-related changes in dynamic balance (DB) ability, and the relationship between DB ability and isometric knee extension strength (IKES). Subjects were 100 females who regularly performed some light gymnastic exercises at a gymnastics club once or twice a week. Subject ages ranged from 20 to 85 years old. The measured items were height, body weight (BW), IKES, and DB ability. Results were as follows: 1. The average DB ability tended to gradually decrease as the subjects got older. There were some significant differences in the average DB ability between the 20 to 29 and 60 to 69 age groups, and between the 20 to 29 and over 70 age groups. 2. It was shown that there was a significant negative correlation between age and DB ability (r=0.471, p<0.001). 3. There was a significant negative correlation between age and IKES/BW (r=0.579, p<0.001). 4. It was shown that there was a significant positive correlation between IKES/BW and DB ability (r=0.368, p<0.001). 5. There was a significant negative correlation between BMI and DB ability (r=0.370, p<0.001). This study showed that DB ability rapidly decreased over 60 years old, and also the value tended to be higher in persons with a higher knee extension strength and lower BMI. Therefore, it was suggested that it is important to increase the knee extension strength and maintain an appropriate BMI in order to maintain DB ability.