Monitoring of Eccentric Hamstring Strength and Eccentric Derived Strength Ratios in Judokas from a Single Weight Category

Background: This study was designed to perform isokinetic knee testing of male judokas competing in the under 73 kg category. The main aims were: to establish the concentric (CON) and eccentric (ECC) strength profile of hamstrings (H) and CON profile of quadriceps (Q) muscles; to evaluate the differences in CON and ECC peak torques (PT) with various strength ratios and their bilateral asymmetries; the calculation of the dynamic control ratio (DCR) and H ECC to CON ratio (HEC); Methods: 12 judokas competing on a national and international levels with a mean age of 19 ± 4 years, a weight of 75 ± 2 kg and with a height of 176 ± 5 cm were tested. All the subjects were right-hand dominant. Isokinetic testing was performed on iMOMENT, SMM isokinetic machine (SMM, Maribor, Slovenia). The paired t-test was used to determine the difference between paired variables. The level of significance was set at p ≤ 0.05; Results: Statistical differences between left (L) and right (R) Q PT (L 266; R 241 Nm), H ECC PT (L 145; R 169 Nm), HQR (L 0.54; R 0.63), DCR (L 0.55; R 0.70), HEC (L 1.02; R 1.14) and PTQ/BW (L 3.57; R 3.23 Nm/kg) were shown. Bilateral strength asymmetries in CON contraction of 13.52% ± 10.04 % for Q, 10.86% ± 7.67 % for H and 22.04% ± 12.13% for H ECC contraction were shown. Conclusions: This study reports the isokinetic strength values of judokas in the under 73 kg category, emphasising eccentric hamstring strength and eccentric derived strength ratios DCR and HEC. It was shown that asymmetries are better detected using eccentric testing and that the dominant leg in judokas had stronger eccentric hamstring strength resulting in higher DCR and HEC.

Rectus femoris muscle thickness and cross-sectional area on ultrasonography may predict isometric and isokinetic knee extension strength: A cross-sectional study

Objective: To examine the relationship between knee extensor strength and quadriceps muscle architecture evaluated with ultrasonography during relaxed and contracted situations. Materials and Methods: A total of 40 healthy participants (age range 18-40), doing sports at a recreational level were included. Pennation angle, muscle thickness, and cross-sectional area of the vastus medialis, vastus lateralis, and rectus femoris muscles were measured firstly during rest while participants are sitting on an isokinetic dynamometer with their knees at 0° and 60° of flexion. Thereafter, ultrasound evaluations were performed during maximal isometric contraction at 60° knee flexion and maximal isokinetic contraction at 30°/sec and 60°/sec speeds. The architectural parameters were correlated with peak isometric (measured at 60° knee flexion) and isokinetic (measured at 30°/sec and 60°/sec angular velocities) torque values. Results: Pennation angle (p<0.001), muscle thickness (p<0.001) and muscle cross-sectional area (p<0.001) of the vastus medialis muscle during rest, and isometric and isokinetic maximal contractions were higher than the vastus lateralis and rectus femoris muscles. Pennation angle, muscle thickness and muscle cross-sectional area parameters measured during rest, and isometric and isokinetic maximal contractions in the vastus medialis (r=0.39-0.64, p<0.05-0.01) and vastus lateralis (r=0.36-0.68, p<0.05-0.01) showed weak to moderate correlations with isometric and isokinetic peak torque. In rectus femoris muscle, on the other hand, except the weak correlation in pennation angle (r=0.35-0.49, p<0.05-0.01), muscle thickness (r=0.74-0.80, p<0.001) and cross-sectional area (r=0.71-0.80, p<0.001) had a moderate to strong correlation with isometric and isokinetic strength. Stepwise regression analysis indicated that rectus femoris cross-sectional area measured during knee relaxed at 60° flexion (R2=0.532-0.610) and rectus femoris muscle thickness measured during isometric and isokinetic contraction modes (R2=0.538-0.600) were decisive to predict the isometric and isokinetic strength of the quadriceps muscle. Conclusion: Contrary to pennation angle, muscle thickness and cross-sectional area of the rectus femoris measured during relaxed and contracted conditions may be determinative in predicting isometric and isokinetic strength.

Sarcopenia in the elderly versus microcirculation, inflammation status, and oxidative stress: A cross-sectional study

BACKGROUND: Age-related mechanisms of sarcopenia associated with vascular function have been recently suggested. This study compared and tested associations between muscle mass and strength, microcirculation, inflammatory biomarkers, and oxidative stress in older adults classified as sarcopenic and non-sarcopenic. METHODS: Thirty-three physically inactive individuals (72±7 yrs) were assigned to age-matched sarcopenic (SG) and non-sarcopenic (NSG) groups. Between-group comparisons were performed for appendicular skeletal mass (ASM), handgrip and isokinetic strength, microvascular function and morphology, C-reactive protein, insulin-like growth factor-1, tumor necrosis factor-alpha, interleukin-6 (IL-6), soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1, endothelin-1, and oxidized low-density lipoprotein. RESULTS: ASM and knee isokinetic strength were lower in SG than NSG (P < 0.05). No difference between groups was found for outcomes of microvascular function and morphology, but log-transformed IL-6 concentration was twice greater in SG vs. NSG (P = 0.02). Correlations between ASM index, handgrip and knee isokinetic strength vs. markers of microcirculatory function, capillary diameters, vascular reactivity, and endothelial injury were found only in SG. CONCLUSION: Decreased ASM index and strength have been associated with microcirculatory profile, indicating that microcirculation impairment may be involved somehow in Sarcopenia development. The inflammation status, particularly elevated IL-6, seems to play an important role in this process.

Shoulder Isokinetic Strength Deficit in Patients with Neurogenic Thoracic Outlet Syndrome

Neurogenic thoracic outlet syndrome (NTOS) is an impairing painful condition. Patients usually report upper-limb pain, weakness and paresthesia. Shoulder weakness is frequently reported but has never been described with objective strength evaluation. We aimed to compare isokinetic shoulder strength between patients with NTOS and healthy controls. Patients and controls were prospectively evaluated with an isokinetic strength test at 60 and 180°/s, and an endurance test (30 repetitions at 180°/s) of the shoulder rotators. Patients were functionally assessed with QuickDASH questionnaires. One hundred patients and one hundred healthy subjects were included. Seventy-one percent of patients with NTOS were females with a mean age of 39.4 ± 9.6. They were compared to controls, 73% females and the mean age of 38.8 ± 9.8. Patients’ mean QuickDASH was 58.3 ± 13.9. Concerning the peak of strength at 60°/s, the symptomatic limbs of patients with NTOS had significantly 21% and 29% less strength than the control limbs for medial and lateral rotators, respectively (p ≤ 0.001). At 180°/s, the symptomatic limbs had significantly 23% and 20% less strength than the controls for medial and lateral rotators, respectively (p ≤ 0.001). The symptomatic limbs had significantly 45% and 30% less endurance than the controls for medial and lateral rotators, respectively (p ≤ 0.001). These deficits were correlated to the QuickDASH. Patients with NTOS presented a significant deficit of strength and endurance of the shoulder rotators correlated to disability. This highlights the interest in upper-limb strength evaluation in the diagnostic process and the follow-up of NTOS.

EARLY STRENGTH TESTING AFTER ACL RECONSTRUCTION IMPACTS ISOKINETIC STRENGTH PERFORMANCE AT TIME OF RETURN TO SPORT

Background: The standard of care in ACL reconstruction (ACLR) typically involves standardized strength testing at 6 months or later to assess a patient’s readiness to return to play (RTP) using isokinetic and isometric testing, and functional strength testing. Recent literature suggests that isokinetic knee extension strength should demonstrate 89% limb symmetry index (LSI) or greater prior to returning to sport. However, there is little known on the effects of strength testing early in the rehabilitation process and the relationship to strength test performance at time of RTP. Purpose: The purpose of this study was to examine how early post-operative strength test performance impacts isokinetic strength outcomes at RTP testing in adolescents. Methods: The retrospective cohort study included patients undergoing primary ACLR between 12 and 18 years of age, early post-operative strength measures, and isokinetic dynamometer strength at RTP from July 2017 and April 2019. Data was dichotomized into desired outcomes at 3 months: >70% isometric knee extension LSI, > 20 repetitions on anterior stepdown test (AST), > 90% LSI Y Balance. At RTP testing, isokinetic knee extension strength data was categorized into >89% LSI at 3 speeds (300, 180, 60°/sec). Chi square testing and odds ratio statistics were used to examine association and its magnitude. Results: 63 patients met inclusion criteria (38 females; 15.37±1.66 years old). >70% LSI isometric knee extension strength at 3 months showed a significant association (Table 2) and demonstrated the strongest odds of having >89% LSI on isokinetic strength tests at all 3 speeds at RTP with 180°/sec being the highest (OR=14.5; 95% CI=4.25,49.43; p= <0.001). Performance on AST showed a significant association (χ2 (1, n=63) = 17.00, p <0.001), and highest odds at 180°/sec (OR=4.61; 95% CI = 1.59, 13.39, p=<0.001) and 60°/sec (OR= 3.07; 95% CI = 1.10, 8.63, p= 0.04). Combination of performance on isometric strength tests and AST showed a significant association to isokinetic strength at all three speeds, but less predictive then isometrics in isolation. (Table 2). There was no significant relationship between YBR LSI at 3 months and isokinetic strength at 6 months. Conclusion: Standardized strength testing early in rehabilitation can help identify patients that will successfully complete RTP testing. Our results suggest that isometric knee extension strength and timed anterior stepdown test provide meaningful clinical information early in the rehabilitation process. This data also suggests that the use of YBAL for predicting isokinetic strength performance is limited. [Table: see text][Table: see text]

NERVE BLOCKS FOR PEDIATRIC ACL RECONSTRUCTION: COMPARING FUNCTION, PATIENT-REPORTED OUTCOMES, AND EFFICIENCY

Background: Previous studies have compared the use of continuous nerve catheter versus single-shot nerve block approaches to regional anesthesia in ACL Reconstruction (ACLR), but they have primarily focused on adult populations. A paucity of data exists comparing these regional anesthesia techniques in children. Hypothesis/Purpose: To compare postoperative pain, strength, and functional outcomes between pediatric ACLR patients undergoing femoral nerve catheter (FNC) placement with single-shot sciatic block and those receiving femoral and sciatic single-shot nerve blocks (SSNB). Methods: Pediatric patients (≤18 years) undergoing primary ACLR between 1/2018-8/2019 at an urban tertiary care children’s hospital were identified. Patients were grouped based on regional anesthetic technique (FNC vs. SSNB). Emergency department (ED) visits, clinic visits, and calls for uncontrolled pain and narcotic refills were compared between these two groups. Outcomes including PROMIS scores, strength testing, and active range of motion (AROM) were also compared. Multiple imputation analysis was used to reduce bias as a result of missed follow-up. Results: 78 patients met inclusion criteria (FNC-36 patients, SSNB-42 patients). There were no differences in age, sex, BMI, or surgical technique between cohorts (Table I). Block preparation time (p<0.001) and surgical duration (p<0.001) were significantly longer for the FNC group. Ropivacaine dose (mg) of the sciatic nerve block was significantly higher in the SSNB group (35.0 ± 7.5 vs. 30.1 ± 4.1, p=0.001). All SSNB cases were performed at a satellite surgical center compared to 1 (2.8%) FNC case (p<0.001). There were no differences in uncontrolled pain or required narcotic refills between groups, and at 1 week follow-up, the proportion of patients with continued opioid consumption was not different (Table II). At 1 week, SSNB patients reported higher PROMIS physical function - mobility scores (25.5 ± 5.6 vs. 22.1 ± 4.9, p=0.009) with no difference in PROMIS pain interference scores. PROMIS scores were not different between cohorts at 6 weeks, 3 months or 6 months. AROM in extension and flexion also showed no difference between groups. SSNB was associated with a higher hamstrings to quadriceps ratio (quadriceps deficit) at 3 months (77.4 ± 23.8 vs. 66.2 ± 18.0, p=0.028), but there were no differences in isokinetic strength at 6 months. Conclusion: SSNB was associated with shorter operative times and better PROMIS physical function – mobility scores at 1 week compared to FNC. No other differences were observed in post-operative pain management, and cohorts were without differences in AROM and isokinetic strength by 6 months. Tables/Figures: [Table: see text][Table: see text]