Isokinetic Testing Research Articles

Aerobic capacity of healthy young men associated with muscle oxygen extraction rate of the vastus lateralis muscle.

The determinants of aerobic capacity are oxygen delivery by the cardiopulmonary system and oxygen extraction by the skeletal muscles. However, the impact of the oxygen extraction capacity of the skeletal muscle is unclear. This study aimed to examine the associations between aerobic capacity; muscle strength, endurance, mass, and quality; and oxygen extraction capacity. Twenty-seven healthy young men (mean age, 20.7 ± 0.8 years; body mass index, 21.6 ± 3.2 kg m-2) were recruited. The following parameters were determined: peak work rate (WR) and oxygen uptake (V˙O2) corrected for body mass using the cardiopulmonary exercise testing; muscle strength and endurance using isokinetic muscle testing; muscle mass using bioelectrical impedance; muscle quality (muscle echo intensity) using an ultrasound imaging device, and muscle oxygen extraction rate (MOER) using near-infrared spectroscopy. Multiple regression analysis was performed using WR/kg peak and V˙O2/kg peak as dependent variables and each assessment index as an independent variable. Multiple regression analysis with WR/kg peak as the dependent variable resulted in the adoption of SMI (β = -0.41, P = 0.036), muscle echo intensity (β=-0.45, P = 0.012) and ΔMOER (β = 0.73, P < 0.001) as significantly associated factors. Multiple regression analysis with V˙O2/kg peak as the dependent variable resulted in ΔMOER (β = 0.65, P = 0.001) being adopted as a significantly associated factor. These findings suggest that muscle oxygen extraction rate is associated with aerobic capacity. MOER is a useful indicator because it is not affected by body mass.

Which technique provides more benefits in return to sports and clinical outcomes after anterior cruciate ligament reconstruction: Double-bundle or single-bundle? A randomized controlled study.

The achievement of an optimal return to sport (RTS) has remained a key goal after sports-related injuries, with the ongoing debate on the effectiveness of different surgical approaches for anterior cruciate ligament (ACL) rupture. This study aims to assess clinical outcomes and RTS across various surgical methods, such as anatomical single-bundle reconstruction (ASBR), central-axial single-bundle reconstruction (CASBR), and double-bundle reconstruction (DBR). A randomized clinical trial was conducted, comprising 191 patients who underwent ACL rupture. These patients were divided into three groups based on the ACL reconstruction techniques they received (ASBR, CASBR, DBR). Over the 2-year follow-up period, the study assessed RTS through four single-hop tests, isokinetic extension tests, and limb asymmetry indices. Postoperative graft status was determined using the signal-to-noise quotient (SNQ), while knee function was evaluated using the International Knee Documentation Committee 2000 (IKDC-2000) score, Lysholm score, Tegner score, and degree of knee laxity. A binary logistic regression model was developed to forecast the factors influencing ideal RTS. DBR (67.63%) and CASBR (58.00%) exhibited higher RTS passing rates compared to ASBR (30.39%; χ2=19.57, P<0.05). Quadriceps strength symmetry in the lower limbs was identified as the key determinant of RTS (χ2=17.08, P<0.05). The RTS rate was influenced by SNQs of the graft's tibial site (odds ratio: 0.544) and quadriceps strength of the reconstructed knee joint at 60°/s (odds ratio: 6.346). Notably, the DBR group showed enhanced knee stability, evidenced by superior results in the Lachman test (χ2=13.49, P<0.01), objective IKDC-2000 (χ2=27.02, P=0.002), and anterior instability test (χ2=9.46, P <0.01). Furthermore, DBR demonstrated superior clinical outcomes based on the Lysholm score (DBR: 89.57±7.72, CASBR: 83.00±12.71, ASBR: 83.21±11.95; F=10.452, P<0.01) and IKDC-2000score (DBR: 90.95±7.00, CASBR: 84.64±12.68, ASBR: 83.63±11.41; F=11.78, P<0.01). For patients with ACL rupture, more ideal RTS rate and clinical outcomes were shown in the DBR group than in the ASBR and CASBR groups. Autograft status and quadriceps strength are postively related to RTS. ClinicalTrials.gov (NCT05400460).

Isokinetic assessment of the female’s soccer player’s knee. A systematic review of outcomes measures

BackgroundIsokinetic normative data in females’ soccer players is scarce in comparison to males. Furthermore, evaluation protocols employed to obtain those data in female’s studies, strongly differ from each other, using different ranges of speeds and movement patterns, thus producing different output data. Thus, it is difficult for the researcher and the clinician to choose a correct protocol for knee isokinetic test in female soccer players. Aim of this paper is to review the literature to provide updated information on how to interpret a knee isokinetic testing in healthy females.MethodsGoogle Scholar, PubMed, Sport Discus, and Psych info databases were queried, and 17 papers were selected. Following PRISMA methodology and PEDro scale, we classified the retrieved papers and assessed the quality.ResultsIn this review some common features of isokinetic testing in female soccer players of various levels of qualification are highlighted. The isokinetic performance indexes widely accepted are the hamstring/quadriceps (H/Q) ratio and dominant/non-dominant (D/ND) ratio. It also emerges that, 3 reps at the speed of 60°/sec in knee flexion/extension are preferable due to the higher reliability and that the optimal H/Q ratio in healthy female soccer players of different level of qualification and age is 50%, while the interlimb differences (D/ND) should be below 10%.ConclusionsNormative data and methodologies reviewed can be useful for the isokinetic test of female soccer players. It emerges that simplifying test procedures limiting at few testing speed and considering selected H/Q and D/ND gives all the necessary relevant informations.

Residual Performance and Biomechanical Asymmetries During Jumping Tasks in Female Athletes at 9 Months After Anterior Cruciate Ligament Reconstruction.

Biomechanics and anterior cruciate ligament injury mechanisms differ in males and females. There is a need for more data on between-limb biomechanical differences after anterior cruciate ligament reconstruction (ACLR) in females. To explore biomechanical asymmetries throughout the kinetic chain during the single-legged (SL) and double-legged (DL) countermovement jump (CMJ) and drop jump (DJ) in female athletes after ACLR. Descriptive laboratory study. Kinematic and kinetic between-limb differences were analyzed during the SL and DL CMJ and DJ in 67 female athletes 9 months after ACLR. Biomechanical and performance asymmetries between limbs during the jumps and isokinetic strength testing were analyzed with statistical parametric mapping. The entire stance phase was used for the paired t tests of the biomechanical variables, with Cohen d effect sizes of significant portions of the stance phase (reported as % of stance) calculated in a point-by-point manner. Decreased vertical ground-reaction force, internal knee abduction moment, knee internal rotation angle, hip external rotation angle, internal ankle eversion, and external rotation moments were seen in the ACLR limb during all 4 vertical jump tests. The greatest number and highest value of differences were found during the DLDJ, with asymmetries having medium to large effect sizes. They tended to appear more frequently in the concentric phase (50% to 100% of stance) during the SLCMJ and DLCMJ and in the eccentric (0% to 49% of stance) and concentric (50% to 100% of stance) phase during the SLDJ and DLDJ. For the SLCMJ, SLDJ, and quadriceps strength, performance asymmetries of >15% were detected but not for change of direction. The findings suggest that return-to-play testing in female athletes should examine the entire stance phase and include assessments of kinetic and kinematic variables throughout the kinetic chain. Greater deficits were highlighted in the DJ than in the CMJ, and greater performance asymmetries were evident in the SL tasks, with greater kinetic and kinematic and compensatory strategies evident in the DL tests. Biomechanical analysis focusing on contralateral compensation strategies and sex-specific interventions are necessary before return to play.

Fitness, Gray Matter Volume, and Executive Function in Cognitively Normal Older Adults: Cross-Sectional Findings From the AGUEDA Trial.

The aim of the study is to investigate the association of cardiorespiratory fitness (CRF) and muscular strength indicators with gray matter volume (GMV) and to study whether fitness-related regions of GMV are associated to executive function (EF) in cognitively normal older adults. Ninety-one cognitively normal older adults (71.69 ± 3.91 years; 57.14% females) participated in this study from the AGUEDA trial. CRF was measured by a 2-km walking test and a 6-min walking test. Muscular strength was measured by handgrip, biceps curl, squats, and isokinetic strength tests. T1-weigthed images were obtained through a magnetic resonance scan. GMV was determined by voxel-based morphometric analysis. Standardized EF tests were performed. CRF did not show any positive association with GMV. Handgrip strength was positively associated with GMV (p < 0.001) in nine regions (β from 0.6 to 0.8 and k from 106 to 1927) and knee extension strength in three regions (β from 0.4 to 0.5 and k from 76 to 2776). Squats strength was negatively associated with GMV (p < 0.001) in two regions (β = -0.3, k = 1102 and k = 152) and the 2-km walking test in one region (β = -0.4, k = 99). Only handgrip strength-related GMV was associated with cognitive flexibility (p = 0.039, β = 0.215) and spatial working memory (p < 0.03, β 0.247-0.317), but not with EF score (p > 0.05). Muscular strength, but no CRF, may be positively related to GMV in cortical and subcortical regions, with implications for specific cognitive domains rather than the overall EF score. Specifically, handgrip strength was the indicator most associated with higher GMV, while squats strength and CRF were negatively related to GMV. ClinicalTrials.gov identifier: NCT05186090.

Association of the COVID-19 Pandemic With Outcomes After Anterior Cruciate Ligament Reconstruction: A Retrospective Comparative Study Examining Changes in Health Care Access, Delivery, and Functional Outcomes.

Structured rehabilitation optimizes outcomes and reduces reinjury risk after anterior cruciate ligament reconstruction (ACLR). The coronavirus 2019 (COVID-19) pandemic interrupted standard rehabilitation, possibly affecting ACLR outcomes. To characterize changes to ACLR functional outcomes related to the COVID-19 pandemic. Cohort study; Level of evidence, 3. Patients who underwent ACLR between June 11, 2019, and March 11, 2020, (postpandemic group) were compared retrospectively with those who underwent ACLR the year before (June 11, 2018, to March 11, 2019). A mixed-effects linear regression model was used to estimate group differences in isokinetic quadriceps testing. A Kaplan-Meier analysis assessed the probability of achieving >90% limb symmetry index (LSI) for isokinetic quadriceps strength at 60 deg/s and passing all return-to-sport functional outcomes at 1 year postoperatively. A total of 176 patients (80 in the control group and 96 in the postpandemic group) were included. The rate of achieving >90% LSI in isokinetic strength at 60 deg/s at 1 year postoperatively was 39% (95% CI, 27%-49%) for the control group versus 22% (95% CI, 13%-30%) for the postpandemic group (P = .01). Similarly, the rate of achieving >90% LSI in all functional tests at 1 year postoperatively was 15% (95% CI, 7%-22%) for the control group versus 7% (95% CI, 2%-12%) for the postpandemic group (P = .04). The number of in-person physical therapy visits per patient was 25.8 ± 6.8 in the control group versus 24.4 ± 7.5 in the postpandemic group (P = .23). Only the postpandemic group accessed physical therapy using remote telemedicine. Each additional telehealth rehabilitation visit was associated with a 1-week delay in achieving >90% LSI in isokinetic quadriceps strength for the postpandemic group. The COVID-19 pandemic was associated with a decrease in lower extremity strength and a lower probability of achieving limb symmetry and passing the criteria for return to sport at 1 year postoperatively. These results were not due to lack of access to physical therapy.

Clinical and radiological outcome of acute quadriceps tendon repair at 2 - year follow-up.

Though previous studies on surgical quadriceps tendon repair reported good to satisfactory results its impact on knee extensor strength and patellofemoral joint is unknown. The purpose of the study was to assess the clinical and functional outcome by quantifying subjective knee related outcome, isokinetic extensor strength complemented by magnetic resonance imaging (MRI). For this retrospective clinical trial twenty-one patients with a mean age of 59.1 (±14.9) years were carried out for follow-up evaluation. For clinical outcome numeric rating scale for pain (NRS), Kujala anterior knee pain score, Knee osteoarthritis outcome score (KOOS) with its subscores, Tegener Activity Score (TAS), Isokinetic extensor strength testing (ISO) and the Limb symmetry index (LSI) were utilized. Muscle volume (Vmqf), atrophy and cartilage status were assessed on MRI. Tendon integrity and implant loosening were evaluated. Statistical analysis was carried out using Student´s t-test, Pearson and Spearman correlation coefficient. Mean follow-up was 56.2 (± 17.5) months. Clinical outcomes in mean were as follows: NRS 1.7 (±2.0), Kujala score 75.8 (± 15.8) points; KOOS 62.9 (±30.6) % (Subscores: (KOOSPain 84 (± 18.3)%, KOOSSymptoms 63.4 (± 15.3) %, KOOSADL 79.8% (± 19.4)%, KOOSSports&Rec 61.5 (± 28.8))%, TAS 3.7 (± 1.2). Mean ISO difference was 3.7 (±32.3) %). 41.2% of patients had an LSI < 90% and showed non-significantly (p > 0.05) better outcomes in NRS, Kujala score and KOOS than patients with LSI < 90%. ISO correlated with better subjective outcome (r > 0.5) but not with MRI findings. Vmqf asymmetry > 10% was seen in 41,2% of patients. Degenerative muscle and cartilage changes were few and low grade. One tendon showed partial retear. Patients showed no signs of implant loosening. Distal quadriceps tendon repair leads to satisfactory subjective outcome in patients with low to moderate activity levels. Tendon integrity was reliably restored. However, extensor strength deficits remain in more than 40% of patients. Atrophy signs of advanced fatty infiltration were recorded in 15% and patellofemoral cartilage defects in 20% of all patients, indicating that previous assessment tools do not display functional outcome adequately.

Potential financial loss and risk factors for hamstring muscle injuries in elite male Brazilian soccer players: a season-long prospective cohort pilot study.

The aim of this pilot study was to analyze the potential financial loss and a range of potential risk factors for hamstring muscle injuries in elite Brazilian soccer. Thirty-four male players (age: 25 ± 6 years; stature: 180 ± 8 cm; body mass: 78 ± 9 kg; minutes played in matches: 2243 ± 1423 min) from an elite professional soccer club were monitored during a 12-month season. Muscle injury was identified by magnetic resonance imaging and the severity was defined according to the number of days away: minimal (1-3 days), mild (4-7 days), moderate (8-28 days), severe (>28 days). Potential financial loss due to the team's under achievements was determined. Dorsiflexion range of motion, eccentric knee flexor strength and isokinetic tests were performed during the pre-season. Association between dependent variables and the occurrence of injury was evaluated. Nine hamstring muscle injuries with moderate severity were found in 8 athletes. Recovery time was 22 days off the field on average. Potential financial loss was $-43.2 million USD and earnings on merit money was 21%. Previous injury, increased flexor deficit 60° /sec and increased flexor fatigue index 300°/sec were all associated with a greater chance of hamstring muscle injury. Ankle dorsiflexion range of motion was significantly lower in the injured group (35.6 ± 3° vs. 39.1 ± 4.9°; p = 0.017, effect size = -0.74). High financial burden was found in elite Brazilian soccer during one full season. Injured athletes had high hamstring fatigue index, knee flexor strength deficit, ankle range of motion restriction and previous hamstring muscle injury when compared to non-injured athletes. Therefore, preventive approaches in professional soccer players with previous hamstring injuries should be a priority.

Three-month functional training programme improves knee joint function in athletes post-ACL reconstruction surgery.

Rehabilitation and recovery duration following anterior cruciate ligament reconstructive surgery play a pivotal role in restoring optimal knee functionality in athletes. This study aimed to explore the impact of a 3-month functional training programme aligned with enhanced recovery after surgery on recuperation subsequent to anterior cruciate ligament reconstructive surgery. A quasi-experimental study. A cohort of 34 patients aged 14 to 24, who underwent anterior cruciate ligament reconstructive surgery and adhered to enhanced recovery after surgery protocols during the perioperative period, were allocated to an experimental group and a control group according to their eligibility, capacity, and willingness to engage in the functional training programme. The participants in the experimental group underwent a 3-month regimen of functional training following anterior cruciate ligament reconstructive surgery, whereas the control group followed a conventional recovery approach. Evaluations were conducted both prior to and following the 3-month recovery interval, utilizing the Y-Balance Test, Functional Movement Screening, and Isokinetic Knee Test. Assessment outcomes of the Y-Balance Test, Isokinetic Knee Test, and Functional Movement Screening exhibited significant enhancement (p < 0.05) within the experimental group, as opposed to the control group. These findings underscore that those athletes who undertook the 3-month functional training regimen within the experimental group exhibited heightened dynamic balance capabilities, increased knee joint mobility, and enhanced stability compared with their counterparts in the control group. Consequently, this underscores the efficacy of the 3-month functional training protocol aligned with enhanced recovery after surgery, as a means to effectively facilitate recuperation subsequent to anterior cruciate ligament reconstructive surgery.

Reduced Knee Flexion Strength 18 Years After ACL Reconstruction With Hamstring Tendon Versus Patellar Tendon

Background: Bone–patellar tendon–bone (BPTB) and double-looped semitendinosus and gracilis (hamstring) grafts are commonly used for anterior cruciate ligament (ACL) reconstruction. Short-term and midterm studies show little or no differences between the 2 grafts; however, there are only a few long-term studies to compare results between the 2 grafts. Purpose: To compare the results after using either BPTB grafts or hamstring tendon grafts 18 years after ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence 2. Methods: A total of 114 patients with ACL rupture between 2001 and 2004 were randomized to reconstruction with either a BPTB graft or a hamstring tendon graft. Patients were operated on at 4 major hospitals. The 18-year follow-up evaluation included anterior knee laxity measured with a KT-1000 arthrometer, defined as the primary outcome, while clinical examination (Lachman and pivot-shift tests), isokinetic testing of muscle strength, patient-reported outcome measures, and an assessment of radiographic osteoarthritis using the Kellgren-Lawrence classification were defined as secondary outcomes. Results: A total of 96 patients (84%, 47 BPTB and 49 hamstring grafts) were available for follow-up, 71 of these for clinical examination. Seven of 96 patients were excluded for ACL revision (n = 5) or knee replacement (n = 2) surgery. In total, 25 patients (10 BPTB and 15 hamstring grafts) had undergone additional surgery other than ACL revision or total knee arthroplasty. There were no significant differences between the groups in terms of anterior laxity test with KT-1000 arthrometer (primary outcome). In secondary outcomes, no significant differences between groups were reported regarding clinical examination, patient-reported outcome scores, or radiographic osteoarthritis (Kellgren-Lawrence grade 2-4 for patellofemoral joint [18 hamstring and 14 BPTB] or tibiofemoral joint [20 hamstring and 19 BPTB]), while isokinetic testing revealed that the hamstring group had a 10.7% reduction in mean peak flexion torque compared with the BPTB group at 60 deg/s (df = 59; P = .011). At 60 deg/s the mean total flexion work in the hamstring group was reduced by 17.2% compared with the BPTB group (df = 59; P = .002). Conclusion: The flexion strength in the hamstring group was significantly reduced in the operated knee after 18 years. There were no significant differences between the groups regarding subjective outcomes, patient-reported outcomes, range of motion, clinical and instrumented knee laxity, and the development of osteoarthritis. Registration: NCT05876013 (ClinicalTrials.gov identifier).

Isokinetic Strength and Balance Analyses for Predicting Return to Sports After the Latarjet Procedure: A Prospective Cross-sectional Study

Background: Isokinetic torque in shoulder internal rotation (IR) and external rotation (ER) can be considered as potential indicators for dynamic stability of the glenohumeral joint. Purpose: To assess the efficacy of 4-month isokinetic testing in predicting the 6-month return-to-sports (RTS) status after Latarjet surgery, explore its correlations with testing parameters, and identify optimal thresholds to ensure a safe RTS. Study Design: Cohort study; Level of evidence, 2. Methods: The study assessed athletes who underwent the Latarjet stabilization procedure between January 2022 and June 2023. The primary outcome was RTS at 6 months after surgery. The primary examined predictors were isokinetic testing metrics at 4 months postoperatively. Secondary outcomes comprised the modified Closed Kinetic Chain Upper Extremity Stability Test (mCKCUEST) and several patient-reported outcome measures, including the Walch-Duplay score, the Western Ontario Shoulder Instability Index (WOSI), and the Shoulder Instability–Return to Sports after Injury scale. To assess the predictors, patients were divided into those who returned to any level of sports compared with those who did not return to sports. The correlation between isokinetic testing results and other outcome scores was also analyzed. Results: A total of 71 patients (mean age, 27.43 ± 9.09 years) were included in the study. Of these, 23.61% did not return to sports, 38.89% returned at a lower level, and 37.50% returned to the same level. Significant rotational strength disparities were noted. Patients who did not return to sports at 6 months demonstrated inferior strength in concentric ER at 60 deg/s, concentric ER at 240 deg/s, concentric IR at 240 deg/s, and eccentric IR at 30 deg/s (P < .05). Similar trends appeared for all studied patient-reported outcome measures and the mCKCUEST (P < .05). Receiver operating characteristic analysis emphasized the significance of isokinetic testing in concentric ER at 240 deg/s (area under the curve = 0.759; P = .001; cutoff = 0.32 N·m/kg; sensitivity = 100.0%; specificity = 49.1%) and eccentric ER at 30 deg/s (area under the curve = 0.760; P = .001; cutoff = 0.51 N·m/kg; sensitivity = 94.1%; specificity = 49.1%) for RTS prediction. Additionally, ER strength moderately correlated with the Walch-Duplay score across all examined velocities (r = 0.26-0.34; P < .05). The modified WOSI score was weakly linked to ER strength at 240 deg/s and 30 deg/s (r = 0.24-0.25; P < .05) as well as moderately linked to the limb symmetry index in ER at 60 deg/s and 30 deg/s (r = 0.30-0.38; P < .05). Conclusion: Isokinetic testing can act as an independent predictor of successful RTS after Latarjet surgery, with concentric ER at 240 deg/s, concentric IR at 240 deg/s, eccentric ER at 30 deg/s, and eccentric IR at 30 deg/s showing the most accuracy. Strength recovery in ER was associated with better Walch-Duplay and modified WOSI scores.

Cardiopulmonary Response to Acute Exercise before Hemodialysis: A Pilot Study.

Disparities in physical fitness between immediately before dialysis (pre-D) and the day following dialysis (non-D) have not been investigated despite potential adverse factors such as fluid status, uremia, and electrolyte levels in the pre-dialysis period. The effect of acute exercise immediately before hemodialysis (HD) on HD-related hypotension remains unclear. We hypothesized that cardiopulmonary performance and muscular strength would be inferior in the immediate pre-D period compared to those non-D. Twenty patients receiving chronic HD treatments underwent symptom-limited incremental cardiopulmonary exercise testing (CPET) and isokinetic testing both 1-2 h prior to dialysis (pre-D) and non-D. This investigation was a sub-study of a clinical trial assessing the efficacy of a pre-D exercise training program. Blood pressure profiles during HD post-CPET and pre-D exercise training were compared with those during usual HD sessions. No adverse events were observed during the 80 exercise tests. Prior to dialysis, the nadir of the ventilatory equivalent of CO2 was slightly elevated, the resting heart rate was lower, and the peak systolic blood pressure was higher than those non-D. Contrary to our hypothesis, peak <inline-formula><mml:math id="m1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mover accent="true"><mml:mi mathvariant="normal">V</mml:mi><mml:mo>˙</mml:mo></mml:mover><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math></inline-formula> and quadriceps peak torque showed no differences. Blood pressure profiles during HD post-exercise were similar to those during sessions without prior exercise, except for a lower resting systolic blood pressure at the beginning of HD. Cardiopulmonary response and muscular strength in the 1-2 h prior to HD were comparable with those on the day following HD, with only minor clinically insignificant differences. Acute exercise prior to HD did not affect the magnitude of hypotension during HD. This study suggests a potential alternative timing for exercise training or testing in patients undergoing chronic HD.

Greater hip internal rotation range of motion is associated with increased dynamic knee valgus during jump landing, both before and after fatigue.

The aim of this study was to analyse sex-specific differences contributing to dynamic valgus in competitive soccer players before and after a standardised fatiguing protocol. Thirty-nine healthy female and male competitive soccer players (19 females and 20 males) were recruited for the purpose of this study. Bilateral medial knee displacement (MKD) was assessed during drop jump landings using a three-dimensional motion capture system before and after a standardised fatiguing protocol. In addition, all soccer players underwent clinical examinations, including rotational hip range of motion (ROM), isokinetic strength testing and magnetic resonance imaging (MRI) of the hip and knee. Sex-specific and fatigue-dependent differences were reported, and the influence of demographic, clinical and radiographic factors on MKD was analysed via multiple linear regression models. Compared with male soccer players, female soccer players demonstrated a tendency towards increased MKD during drop jump landings before (p = 0.09) and after the fatiguing protocol (p = 0.04). Sex-specific differences included increased hip internal rotation (IR) ROM, decreased hip external rotation (ER) strength and increased femoral torsion in females (all p < 0.002). According to the multiple linear regression models (stepwise method), increased hip IR ROM (90° of flexion) and the non-dominant leg remained the sole independent predictors of increased MKD during drop jump landings before (p < 0.01 and p = 0.02, respectively) and after fatigue (p < 0.01 and p < 0.01, respectively). An increase in hip IR ROM in females was linearly related to MKD after fatigue (R2 = 0.25; p < 0.01). Female soccer players exhibited increased dynamic valgus before and after fatigue, which is likely attributed to joint mobility, as well as muscular and anatomical differences, such as increased hip IR ROM, reduced hip ER strength and increased femoral torsion. In particular, females with increased hip IR ROM were more susceptible to effects of fatigue on MKD, which may increase their risk for anterior cruciate ligament injury. Level III.

In the medium term, more than half of males report kinesiophobia after anterior cruciate ligament reconstruction

ObjectivesAnterior cruciate ligament rupture is a serious trauma with long-term consequences for the patient. Psychological and physiological factors may negatively affect patient recovery after anterior cruciate ligament reconstruction (ACLR), and development of kinesiophobia is possible. The aim of this study was to examine the presence of kinesiophobia and lower-leg muscle strength recovery in both sexes after ACLR. Methods140 ACLR patients agreed to participate in the study. Kinesiophobia was assessed using the Tampa Scale of Kinesiophobia (TSK). The Knee injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS) and Tegner Activity Scale (TAS) were used for patient-related outcome measurements. In both legs quadriceps and hamstring muscle strength at 60°/s and 180°/s were measured with an isokinetic dynamometer. For dynamic balance and leg function, the Y-balance test and single-leg hop test were used. Results100 (71%) males and 40 (29%) females—mean age 32.5 (±8.3)—were examined 5.5 (±1.25) years after ACLR. 68/140 patients (48.6%) reported a TSK kinesiophobia score equal to or higher than 37 points: 54/100 (54%) males and 14/40 (35%) females (p ​= ​0.04). Patients with kinesiophobia had significantly lower KOOS values (p ​< ​0.001). In terms of the TAS no significant differences were found between those with or without kinesiophobia. Knee strength deficiency at 180°/sec and 60°/sec was significantly higher in the kinesiophobia group in knee extension in males (p ​= ​0.009) and knee flexion in females (p ​= ​0.001). Normalized body weight isokinetic average peak torque strength tests were significantly better in males compared to females in both groups (p ​< ​0.001). ConclusionBoth sexes reported high rates of kinesiophobia, but males are at higher risk of developing kinesiophobia than females in the medium term after ACLR. Furthermore, patients with kinesiophobia have significantly lower total KOOS scores, and females were significantly weaker than males in knee flexion and extension according to normalized body weight muscle strength tests. Also, a longer time from injury to surgery increases the risk of kinesiophobia in females. Level of evidenceLevel IV. Type of studyRetrospective case series study. Clinical trial registrationTrial registration in ClinicalTrials.gov. Identifier: NCT05762809.

Recovery after Exercise-Induced Muscle Damage in Subjects Following a Vegetarian or Mixed Diet.

It is unclear if following a vegetarian diet affects muscle recovery after exercise-induced muscle damage (EIMD). Sixteen vegetarians (VEG) and sixteen mixed dieters (MIX) performed a vertical jump, quadriceps femoris maximal isometric, and isokinetic concentric strength tests prior to and five days following the EIMD protocol. The quadriceps muscle was injured by performing eccentric contractions. Diet: MIX consumed more g/kg of animal protein (p < 0.001) and EAA (p < 0.05) except for isoleucine. VEG consumed more plant protein (p = 0.001). Isometric strength: MIX recovered post-day 2, VEG recovered post-day 4 (group (p = 0.07), time (p < 0.001)). Concentric contractions at 60 degrees per second: Both recovered post-day 1 (group (p = 0.27), time (p = 0.05)); 180 degrees per second: MIX recovered post-day 2, VEG recovered post-day 5 (group (p = 0.10), time (p < 0.001)); and 240 degrees per second: MIX recovered post-day 1, VEG did not recover by post-day 5 (group (p = 0.01), time (p < 0.001)). Vertical jump: Both recovered post-day 3 (group (p = 0.45), time (p < 0.001)). MIX recovered isometric strength 2 days faster, concentric strength was up to 5 days faster, and soreness was 1-4 days faster when compared to VEG. Both groups had similar recovery time for power.

Subacromial balloon spacer improves isokinetic performance in patients with massive irreparable rotator cuff tear.

The aim of this study was to analyse clinical, functional and shoulder kinematics results using subacromial balloon spacer in nonreparable massive rotator cuff tears. Subacromial balloon spacer was hypothesised to improve shoulder kinematics and increases clinical and functional outcomes scores in nonreparable massive rotator cuff tears. This is a prospective study in massive rotator cuff tears. From October 2021 to October 2022, a total of 127 shoulders suffering massive rotator cuff tears were initially evaluated. All patients were evaluated preoperatively, at 6 and 12 months. Patients' patient-reported outcome measures (PROM) subjective values using visual analogue scale (VAS) and the Spanish Western Ontario Rotator Cuff Index (WORC) version were analysed. We also evaluated objective outcomes: constant score, range of movement and kinematic shoulder analysis (isokinetic test to evaluate internal and external rotation forces). Statistical analysis was conducted using SPSS software; continuous variables were presented as means and standard deviations (SDs). Seventeen nonrepairable massive rotator cuff tears were finally included. Three patients required reverse shoulder arthroplasty before 6 months postoperative. After 1-year follow-up, objective and subjective (PROM) outcome scores and isokinetic measurements improved in 13 patients. Preoperative VAS improved from 6.5 ± 2.1 to 2 ± 1.9 points on average at 1-year follow-up and WORC index from 1603 ± 217.3 to 699 ± 361.6. Constant score from 42.1 ± 13.1 on average and at 1-year follow-up increased to 60.8 ± 14.7. Range of movement also improved in elevation 122.2 ± 39.3 to 166.9 ± 25.8, abduction 120.3 ± 38.6 to 134.6 ± 21.1, external rotation 30.3 ± 19.7 to 86.1 ± 13.8 and internal rotation L4-T12 on average at 1-year follow-up. Isokinetic evaluation showed functional improvement 1 year after implantation. Both internal and external rotation improved compared with their healthy shoulder. External rotation improved from 30.3° ± 19.7° preoperatively to 86.1° ± 13.8° (43.7% in the isokinetic study) and internal rotation from L4 preoperatively to L1 (49.8% in isokinetic study) on average. Among the different alternatives for irreparable rotator cuff injuries surgical treatment, subacromial balloon spacer is an effective alternative in selected patients, both in terms of clinical-functional improvement and short-term isokinetic results. Level II.

Isokinetic strength testing with different biomechanical demands on core strength: a comparison of military competitive athletes and soldiers with high occupational physical strain

It is known that anthropometric data (weight, height, BMI, waist circumference and WHtR) and male gender are positively correlated with greater core strength, while age is negatively correlated. For competitive athletes with no significant differences in the anthropometric data stated above, there have hardly been any studies in which isometric core strength in a seated position is quantitatively compared among athletes in different sports. This study aimed to analyse different sports in well-trained athletes using military competitive sports as an example with regard to possible differences in core strength. For this purpose, Parachuting (n=28), Military Pentathlon (n=34) and Ski Platoon (n=38) groups were compared with regard to isokinetic core strength using dynamometry in seated position. In addition to the comparison of anthropometry and isokinetic results with descriptive statistics, ANOVA and Welch-ANOVA were used to compare the means of absolute and weight-adjusted core strength. It was shown that the Ski Platoon group had significantly higher flexion peak torque values than the Military Pentathlon and Parachuting groups. Even when adjusted for weight, the values were significantly higher than those measured in the Military Pentathlon group but not significantly higher than those in the Parachuting group. For extension peak torque, it was found that the Military Pentathlon group had significantly lower values than the Ski Platoon group and, in the weight-adjusted analysis, significantly lower values than the Parachuters. Using the example of competitive military sports, this study was able to show that there are significant differences in isokinetic core strength even among professional competitive athletes.This knowledge should be used to carry out detailed quantitative analyses of core strength, even in well-trained professional athletes, to find applications for prevention or to coordinate compensating exercises.

Sequential Comparison of Knee Muscle Strength after Anterior Cruciate Ligament Reconstruction between Hamstring Autograft and Tibialis Anterior Allograft: Propensity Score Matched Pair Analysis.

Among the graft options for anterior cruciate ligament reconstruction (ACLR), hamstring autografts are widely regarded as the preferred choice for primary ACLR among orthopedic surgeons worldwide. However, concerns persist regarding postoperative knee flexor weakness. We aimed to compare knee extensor and flexor strengths between hamstring autograft and tibialis anterior allograft groups in ACLR patients, who were propensity score-matched based on baseline characteristics. A retrospective analysis included 58 matched pairs who underwent isokinetic strength tests at 6 and 12 months post operation. Isokinetic muscle strength tests found no significant difference in knee extensor and flexor strength at 6 months post operation between the hamstring autograft and tibial anterior allograft groups. At 12 months, the hamstring autograft group exhibited significantly greater knee flexor deficit (total work and average power) compared to the allograft group, despite no differences in extensor strength or patient-reported outcomes. This study highlights the impact of hamstring autograft harvesting on muscle strength and recovery following ACLR in short-term period.

Peri-ankle muscles architecture and performance changes inpatients with chronic ankle instability: A retrospective cross-sectional study.

This study aimed to identify changes in the architecture and performance of the peri-ankle muscles in patients with chronic ankle instability (CAI) and investigate the relationship between them. In total, 17 subjects were evaluated retrospectively. Each subject underwent anthropometric and isokinetic test, and peroneus longus (PL) and brevis (PB), medial gastrocnemius (MGCM), and tibialis anterior (TA) ultrasound imaging were performed at rest and maximum voluntary contraction (MVC) conditions. Regarding muscle architectural variables, the pennation angle (PA) of the MGCM at rest and the PA of the TA, MGCM, and PL in MVC were significantly reduced on the injured side compared to the intact side. There were no significant differences in muscle thickness of PL, PB, MGCM, and TA observed between intact and injured side during both rest and MVC. Regarding muscle performance parameters, significant decreased were observed in the muscle strength for both limbs in all four directions under the two different conditions. A secondary finding was that the relative PA ratio of the TA showed moderate correlation with the relative dorsiflexion ratio at 30°/s. These findings can provide opportunities to better understand how injuries in patients with CAI may be related to changes in ankle and foot function.

Poster 321: Predictive Value of Functional Assessments During Perioperative Rehabilitation in Anterior Cruciate Ligament Reconstruction (ACLR)

Objectives: Perioperative rehabilitation is critical to restoring function and preventing reinjury in ACLR patients. Single-leg hop and isokinetic strength testing are commonly utilized by clinicians to assess patient progress. The impact of early stage progress on later stage outcomes is, however, not well understood. This study aimed to identify the effects of early postoperative isokinetic quadriceps strength and single-leg hop performance on functional recovery after primary ACLR, to determine the manner in which changes in these parameters during perioperative rehabilitation relate to fast and successful functional recovery. Methods: Patients having a primary ACLR were consented into a long-term study and were retrospectively reviewed with the following inclusion criteria: ACLR using a contralateral patellar tendon graft with normal extension ROM and stability at 2 months postoperative, per the International Knee Documentation Committee (IKDC) objective form. Patients were excluded with a preoperative modified Tegner level &lt;7. Predictor variables included 180°/second isokinetic quadriceps strength test (preoperative, 2 months, 4 months) and single leg hop for distance (preoperative and 4 months). Strength was assessed using limb symmetry index (LSI) with the ACLR knee strength being divided by the graft donor knee strength, percent of preoperative normal, and percent change over time at each interval, while hop testing was normalized to height. Outcome variables assessed were return to sport (RTS) time in months, return to preoperative modified Tegner level in the first 12 months after surgery (yes/no), and Cincinnati Knee Rating System (CKRS) at 12 months postoperative. Stepwise multiple regression analysis was used to predict RTS time, return to preoperative modified Tegner level, and CKRS based on demographics and objective measures. Results: A total of 1093 patients were eligible for analysis and 607 were used for the RTS model, 724 for the return to preinjury Tegner level model, and 705 for the CKRS model. Mean age for the cohort was 19.6 ± 5.5 years (range, 11.9-39.7) and 52.1% were male. In the model predicting RTS time, the following variables reduced RTS time: female sex, younger age, higher preoperative LSI, higher ACLR knee strength gains from preoperative to 2 month, and higher normalized single leg hop distance. In the model predicting a return to preoperative Tegner level, the following variables increased the likelihood: younger age, lower preoperative Tegner level, lower strength deficits with LSI at 2 months, and higher normalized single leg hop distance. In the model predicting CKRS scores, the following variables increased the score: younger age and higher normalized single leg hop distance. Model statistics can be seen in Table 1. Conclusions: The study found several early rehabilitation performance measures significantly influenced key outcomes. Perioperative rehabilitation should promote early relative gains in quadriceps strength for the ACLR knee, maintaining limb symmTaetry, and maximizing single leg hop distance to encourage faster RTS, higher subjective scores, and improve the likelihood of patients returning to preoperative activity levels. By quantifying the importance and predictiveness of these rehabilitation performance metrics, clinicians may improve their protocols to promote superior outcomes following ACLR.