Single-leg Hop Research Articles

Two-Year Functional Outcomes of Nonsurgical Treatment in Concomitant Anterior Cruciate Ligament and Medial Collateral Ligament Injuries: A Case-Control Study.

The anterior cruciate ligament (ACL) is a common knee injury in high-intensity sports, which can cause early career loss in young athletes. Concomitant damage to other knee stabilizers may occur, such as the medial collateral ligament (MCL). Recent studies have shown that knee stability can increase without surgical intervention in patients with ACL and MCL injuries. Regarding the importance of functional tests in return to exercise prediction, this study aims to measure nonsurgical approach's long-term outcome for concomitant ACL and MCL injuries with a focus on functional tests. This is a case-control study with a 2-year follow-up. The case group consisted of patients who had provided written consent and completed their 2-year follow-up, and the control group was made up of healthy people who did not have any knee medical conditions and were matched by age, gender, and activity level. Physical examinations, Tegner and International Knee Documentation Committee questionnaires, and knee magnetic resonance imaging were conducted, and functional performance tests were performed after a 10-minute warm-up. Lody's index (the ratio of injured-to-uninjured knee results) was calculated. The data were analyzed using independent t-test, one-way analysis of variance, chi-squared test, and Fisher's exact test. The study involved 11 patients in each concomitant ACL and MCL injury cases and healthy control groups with a mean age of 32.4 and 28 years, respectively. None of the patients reported knee instability symptoms in the 2-year follow-up. More than half of the patients continued their sports field without reinjury, with no significant difference in activity levels between case and control groups. The 6-meter hop test and single-leg hop test showed no significant difference between case and control groups (p-value: 0.326, 0.859), and no significant difference was observed in the three Carioca, cocontraction, and Shuttle tests in the 2-year follow-up. Functional tests in ACL and MCL injuries revealed normal outcomes, implying a nonsurgical approach for patients with proximal ACL tears, better knee stability, and no significant differences between the injured and control groups.

Inter-Limb Asymmetry in Female Sepak Takraw Players: An Observational Study

This study investigated the magnitude and direction of inter-limb asymmetry in 21 professional female sepak takraw players across several task-specific tests. Five inter-limb asymmetry assessments were employed: unilateral countermovement jump (Uni-CMJ), bilateral countermovement jump (Bi-CMJ), single-leg hop (SLH), triple hop test (THOP), and isokinetic concentric peak torque of the knee flexors and extensors at 60 deg/s−1, 120 deg/s−1, and 180 deg/s−1 angular velocities. A “true” inter-limb asymmetry was only observed for Uni-CMJ jump height (16.62%) and THOP distance (6.09%). Kappa coefficients demonstrated fair agreement in the direction of asymmetry between the Uni-CMJ and Bi-CMJ tests for jump height (Kappa = 26.67), but only slight agreement for peak force (Kappa = 0.11), propulsive impulse (Kappa = −0.12), and eccentric impulse (Kappa = −0.14). Fair agreement was observed between the SLH and THOP (Kappa = 0.32). Slight to moderate agreement was found for concentric peak torque across angular velocities for the knee extensors (Kappa = 0.08 to 0.48), while fair to nearly perfect agreement was noted for the knee flexors (Kappa = 0.31 to 1). The Uni-CMJ and THOP are most sensitive to detect between-limb asymmetries in female sepak takraw players. Given the inconsistencies in asymmetry direction across tests, monitoring asymmetry direction is important for strength and conditioning.

Effects of Chronic Pain on Static and Dynamic Postural Control in Chronic Ankle Instability.

To identify the effects of chronic pain levels on static and dynamic postural (DP) control in individuals with chronic ankle instability (CAI). Cross-sectional study. Controlled laboratory. Sixty participants were divided into the following 3 groups: 20 high pain individuals with CAI (high pain), 20 low pain individuals with CAI (low pain), and 20 healthy controls (control). Groups (CAI with high pain, CAI with low pain, and control) and visual conditions (eyes open and closed) for single-leg stance. Participants performed single-leg stance with eyes open and closed, the star excursion balance test, and single-leg hop to stabilization. The high pain group experienced worse self-reported outcomes, including Foot and Ankle Ability Measure activities of daily living and sports, than the low pain and control groups. Regardless of visual condition, both the high and low pain groups exhibited decreased static postural control in mediolateral (ML) compared with the control group. Specifically, the high pain group showed decreased static postural control in ML under closed eyes compared with the low pain and the control groups. The high pain group showed less reach distance than the control group and increased DP control in vertical and overall DP stability index compared with the low and control groups. Chronic pain can significantly affect both static and DP control in individuals with CAI. Therefore, clinicians should consider chronic pain as one of the factors affecting postural control in individuals with CAI.

The effect of post-match fatigue on physical performance in adolescent soccer players.

Soccer involves many physically challenging actions and engaging in such activities can induce a decline in performance due to physical fatigue which predisposes players to develop injuries. The present study aimed to examine the impact of post-match fatigue on functional performance and Inter-Limb Asymmetry Index (LSI) in adolescent soccer players. Thirty-eight adolescent male soccer players (15-18 years) completed a battery of functional performance measures (Rate of Perceived Exertion (RPE) scale, 10 m sprint, agility T-test, and Single leg hop for distance (SLHD) test). The data collection started prior to a soccer match and consisted of two testing sessions; two hours before the match, while the subsequent testing session was performed within two hours immediately following the match. The study results revealed a significant effect of post-match fatigue on change of direction abilities and SLHD (moderate effect size). However, no significant differences were observed in the 10 m sprint test and LSI (P>0.05). Functional performance measures such as agility test and SLHD test can detect physical ability changes due to post-match fatigue in adolescent soccer players. The study findings offer insightful and practical information on the importance of employing field-based functional performance measures in monitoring players' recovery following a game.

Poster 342: Return to Sport Rates and Objective Measures after ACL Reconstruction for High Level Basketball Players

Objectives: Return to sports (RTS) decisions for high-level basketball players after an anterior cruciate ligament reconstruction (ACLR) are multifactorial. The literature focuses mainly on sports performance metrics and lacks objective rehabilitation measures. The purpose of this study was to determine objective measure differences following an ACLR between basketball players competing at the college/professional, high school, and recreational levels. Our hypothesis was that basketball players competing at the college/professional level would have superior performance with objective measures following an ACLR, compared to those competing at the high school and recreational levels. Methods: Patients were retrospectively selected based on the following inclusion criteria: ACLR with a contralateral patellar tendon graft (PTG), preoperative activity level of ≥8 on the modified Tegner activity rating scale, ≤25 years old, and reported playing basketball. Exclusions included: revisions, bilateral procedures, or were missing data needed for analysis. Patients were split based on their preoperative activity level (level 8 = recreational, level 9 = high school, level 10 = college/professional). Each patient received a mini open, contralateral PTG utilizing the same surgical methods and followed the same accelerated rehabilitation approach. Postoperative outcome measures included the difference in extension range of motion (ROM) at 2 weeks, difference in flexion ROM at 3 months, percent deficit in isokinetic quadriceps strength and single leg hop for distance at 4 months, and the manual maximum difference on the KT arthrometer at 2 months. Statistical analysis included chi-square and analysis of variance where appropriate. Results: Of the 329 patients, 69 were level 8, 224 were level 9, and 36 were level 10 with mean ages of 19.6, 16.4, and 19.1 years, respectively. The percent of males differed by group with level 8 at 78.3%, level 9 at 29.5%, and level 10 at 27.8% (p < 0.001). The overall rate of return to competitive basketball for the cohort was 96.0%. The rate of return to competitive basketball was not statistically significantly different among the groups with level 10 having the highest rate (97.2%), followed by level 9 (96.4%) and then level 8 (94.2%), p = 0.659. Level 10 athletes had the lowest strength deficit with a mean of 9.3%, compared to 12.5% for level 9, and 15.6% for level 8, p=0.017. Single leg hop deficit was also different among groups with level 10 at 6.9%, level 9 at 6.2%, and level 8 at 10.4%, p < 0.001. Knee ROM and stability were not statistically different among the groups. Conclusions: The rate of return to competitive basketball is the same among all high-level basketball players. Objectively, level 10 athletes had superior strength and single leg hop performance compared to recreational basketball players. Although the return to competitive basketball rate is the same among all groups, recreational basketball players tend to be weaker than college/professional players, therefore, added emphasis on this aspect of their rehabilitation would be beneficial for this population.

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 <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.

Paper 01: Clinical Outcomes Following ACL Reconstruction with Slope Reducing High-Tibial Osteotomy: A Matched Case-Control Study

Objectives: Despite recent efforts, the reinjury rate following anterior cruciate ligament (ACL) reconstruction remains high, with documented reports of up to 30%. According to retrospective evidence, high posterior tibial slope (≥12°) has been identified as an anatomic risk factor contributing increased graft reinjury rates. Surgeons are therefore exploring the effectiveness of slope reducing high tibial osteotomy (SRO) as a means of modifying this potential risk factor. While cadaveric models suggest that this surgical procedure decreases the forces across the ACL graft, there are few clinical trials examining its’ safety and clinical effectiveness in patient samples. Therefore, the purpose of this study is to compare functional performance and graft reinjury rates between patients undergoing ACL reconstruction surgery with SRO versus matched controls undergoing isolated ACL reconstruction. We hypothesized that patients undergoing ACL reconstruction with SRO would exhibit similar performance outcomes with a low failure rate when compared to their matched counterparts. Methods: A retrospective matched-case control study was conducted in accordance with the ‘Strengthening the Reporting of Observational Studies in Epidemiology’ guidelines for patients undergoing ACL reconstruction (Figure 1), utilizing a single surgeon database (n=1978). The experimental group (ACL+SRO) consisted of patients ages 18-50 years old that were at least 24-months out of ACL reconstruction with a concomitant SRO. Patients were age, sex, and revision-matched to a cohort of individuals undergoing isolated ACL reconstruction. Exclusion criteria consisted of contralateral knee injury (<24 months prior to surgery), isolated coronal-plane high tibial osteotomy, and multiligamentous knee injury. Patient demographics and surgical data were obtained, including pre/postoperative posterior tibial slope (o) for the ACL+SRO group and presurgery activity levels. Data were gathered at return to sports and included knee range of motion, single-leg balance, single-leg hop testing, and self-reported International Knee Documentation Committee and ACL-Return to Sports After Injury (ACL-RSI) scores. Complications and injury surveillance was conducted throughout the postoperative follow-up period. Primary outcome measures included the Single Assessment Numeric Scale (SANE), and graft failure rates at two-years. Secondary outcomes included return to sport rate and level of participation, and postoperative complications (infection, loss of motion, deep vein thrombosis, etc). Generalized Linear Models and chi-square analyses were conducted using SPSS (IBM, Chicago IL) to compare groups with an a-priori alpha level of .05. Results: Of the 1978 patients in the ACL registry, 48 met the study criteria and were included in the analyses (ACL+SRO group, n=24; Isolated ACL group, n=24). Baseline comparisons revealed that the ACL+SRO group had a higher bodyweight (200.9 ±35.1 vs 179.7 ±33.9, P <.001) and subsequent higher body mass index (29.7 ±4.6 vs 26.7 ±5.0, P = .044), Table 1. Additional baseline differences included ACL graft type, and staged procedures ( P < .05, Table 2). The mean preoperative posterior tibial slope was 17.0° ±2.7° and 7.0° ±2.2° following SRO (mean diff: -10.0°, P <.001). Table 3 depicts the comparisons at return to sport, with the ACL+SRO group demonstrating longer time to return ( P < .001) and lower ACL-RSI scores ( P = .027). At 2 years, there were no statistical differences in SANE score (85.3 ±7.3 vs 88.2 ±9.7, P = .349), graft reinjury rate (0.0% vs 0.0%, P = 1.000), rate of return to sports (85.7% vs 91.7%, P = .844), or level of return to sports between groups with 45.8% (n=11) of the ACL+SRO group returning to a level I or II cutting and pivoting sport versus 54.2% (n=13) in the Isolated ACL group ( P = .656). There were no reported postoperative infections or deep vein thromboses in either group (P > .05). Conclusions: The current study suggests that SRO in the setting of ACL reconstruction for large posterior tibial slope deformities is effective at correcting malalignment, restoring objective and self-reported function, and avoiding graft failure out to 2 years. This procedure also holds promise to allow a majority of patients to return to various levels of sporting activities. To our knowledge, this is the first comparative study examining the return to sports and 2-year outcomes of this population to a matched isolated ACL cohort. While these data do provide evidence for ongoing investigation, we recommend the performance of larger clinical trials to confirm these results. [Figure: see text][Figure: see text][Figure: see text][Figure: see text]

The acute effect of releasing the thoracolumbar facia by osteopatic technique on lower extremity functional performance on lumbar extensor endurance and mobility in soccer players

Introduction: The aim of this study is to examine the acute effect of osteopathic release of the thoracolumbar fascia on lower extremity functional performance, lumbar extensor endurance and mobility in professional soccer players. Materials and Methods: 30 volunteer male athletes who professionally play soccer participated in the study, and the participants were randomly divided into experimental and control groups. The functional performance of the lower extremities, lumbar extensor endurance and mobility of the subjects were measured twice – before and immediately after the Still Technique and placebo applications. Subjects' lower extremity functional performance was determined by the Single Leg Hop Test, lumbar extensor endurance by the Beiring-Sorensen Extensor Endurance Test, and mobility skill by the Modified Schober Test. Results: According to the results of the statistical analysis, there was a significant difference between the pre-test and post-test values of the lumbar extensor endurance tests of the experimental group in favor of the post-test; however, there was no significant difference in lower extremity functional performance and mobility values, and it was determined that they improved in the post-test. Conclusions: Releasing the thoracolumbar fascia tissue with osteopathic technique before exercise in athletes can acutely increase performance by positively affecting muscle contraction.

Anabolic/Catabolic Hormone Imbalance but Still Jumping Further? Negative Association of Free Testosterone With Jumping Performance in Elite Handball Players Following a Preparatory Period

ABSTRACT Purpose: The present study investigated the effects of a 10-week preparatory training period on biomarkers and jumping performance and associations of changes in biomarkers, load, and jumping performance from the beginning (PRE) to the end of the preparatory period (POST) in elite handball players. Methods: Seventeen elite handball players competing in the first Slovenian men’s League were recruited. Training, competition and academic loads were reported weekly, while biomarkers and jumping performance were assessed at PRE and POST. Results: At POST, decreased levels of free testosterone (large effect size [ES] = -1.69, p < .001) and free testosterone to cortisol ratio [FTCR] (large ES = −.95, p = .004) were observed; whereas, better performance on the single leg lateral hop test [SLLH] (large ES = .85, p = .007) and single leg triple hop test [SLTH] (large ES = 1.05, p = .002) were observed compared to PRE. Furthermore, changes in FTCR correlated with changes in cortisol (high r = -.751, p = .001), SLLH (moderate r = -.603, p = .022), and SLTH (moderate r = -.643, p = .013), while changes in free testosterone correlated with SLTH (moderate r = -.645, p = .013). Conclusions: High intensity trainings with a saturated competition schedule can result in disturbed anabolic/catabolic hormone ratio observed through FTCR decrease, which could indicate either an optimal state or early exhaustiveness. It seems that SLLH and SLTH are more sensitive to changes in biomarkers than a single leg hop test. Sport professionals may use the results for individualized monitoring of an athlete’s health and performance, specifically, as an aid for adjusting training loads accordingly to prevent performance declines and potential injury/illness events.

Effects of Electro-Muscle Stimulation Exercise Combined with Mat Pilates on Pain, Anxiety, and Strength in Sedentary Females with Fibromyalgia: A Single-Blind Randomized Controlled Trial.

Fibromyalgia syndrome (FM) is a chronic pain disorder that is ranked as one of the four most common rheumatological diseases in the world. This study aims to investigate the effects of an eight-week mat Pilates and electro-muscle stimulation (EMS) with combined mat Pilates exercises on pain, depression, anxiety, and strength in sedentary women. This study is a single-blind randomized controlled trial. A total of 30 sedentary female patients (Pilates (n = 15), EMS (n = 15)) diagnosed with FM were included in the study. The patients were subjected to Beck Depression (BDIs) and Anxiety Inventories (BAIs); a Fibromyalgia Impact Questionnaire (FIQ); five different Single-Leg Hop Tests (SLHTs); modified push-up (MPU), Handgrip Strength (HGS), Deep Squat (DSQ), V-Sit Flexor, bent-arm hang (BA), sit-up and Biering-Sørensen tests; and anthropometric tests before and after the 8-week exercise program. The eight weeks of mat Pilates exercises combined with mat Pilates and EMS revealed significant results (p < 0.05) in anthropometric data (abdomen, lower abdomen, hips) (p < 0.05) except for the results of chest circumference measurements (p > 0.05). In addition, there were statistically significant positive results in BDIs, BAIs, FIQs, lower extremity (all SLHTs and DSQ), upper extremity (MPU, HGS, BA), and core (V-SIT, sit-up, Biering-Sørensen test) strength test findings (p < 0.05). Combining the mat Pilates exercises with EMS is an effective and reliable method to improve the pain, anxiety, depression, and strength of female patients diagnosed with FM.

The potential of a targeted unilateral compound training program to reduce lower limb strength asymmetry and increase performance: a proof-of-concept in basketball.

This study investigates the efficacy of training methodologies aimed at mitigating asymmetries in lower limb strength and explosiveness among basketball players. Thirty male university basketball athletes were enrolled in this research. Initial assessments were made regarding their physical attributes, strength, and explosiveness. Subsequently, the participants were randomly allocated into two groups: an experimental group (EG, n = 15) and a control group (CG, n = 15). Over 10 weeks, the EG engaged in a unilateral compound training regimen, incorporating resistance training exercises such as split squats, Bulgarian split squats, box step-ups, and single-leg calf raises (non-dominant leg: three sets of six repetitions; dominant leg: one set of six repetitions) and plyometric drills including lunge jumps, single-leg hops with back foot raise, single-leg lateral jumps, and single-leg continuous hopping (non-dominant leg: three sets of 12 repetitions; dominant leg: one set of 12 repetitions). The CG continued with their standard training routine. Assessments of limb asymmetry and athletic performance were conducted before and after the intervention to evaluate changes. 1) Body morphology assessments showed limb length and circumference discrepancies of less than 3cm. The initial average asymmetry percentages in the single-leg countermovement jump (SLCMJ) for jump height, power, and impulse were 15.56%, 12.4%, and 4.48%, respectively. 2) Post-intervention, the EG demonstrated a significant reduction in the asymmetry percentages of SLCMJ height and power (p < 0.01), along with improvements in the isometric mid-thigh pull (IMTP) test metrics (p < 0.05). 3) The EG also showed marked enhancements in the double-leg countermovement jump (CMJ) and standing long jump (SLJ) outcomes compared to the CG (p < 0.01), as well as in squat performance (p < 0.05). The 10-week unilateral compound training program effectively reduced the asymmetry in lower limb strength and explosiveness among elite male university basketball players, contributing to increased maximal strength and explosiveness.

Residual deficits of knee and hip joint coordination and clinical performance after return to sports in athletes with anterior cruciate ligament reconstruction

BackgroundBiomechanical changes and neuromuscular adaptations have been suggested as risk factors of secondary injury in individuals after anterior cruciate ligament reconstruction (ACLr). To achieve a better understanding of preventive mechanisms, movement quality is an important factor of consideration. Few studies have explored time-series analysis during landing alongside clinical performance in injured and non-injured individuals. The purpose of the study was to investigate the biomechanical risks of recurrent injury by comparing clinical and jump-landing performance assessments between athletes with ACLr and healthy controls.MethodThis study was observational study. Sixteen athletes with and without ACLr voluntarily participated in clinical and laboratory measurements. Single-leg hop distance, isokinetic tests, landing error score, and limb symmetry index (LSI) were included in clinical report. Lower limb movements were recorded to measure joint biomechanics during multi-directional landings in motion analysis laboratory. Hip-knee angle and angular velocity were explored using discrete time-point analysis, and a two-way mixed analysis of variance (2 × 4, group × jump-landing direction) was used for statistical analysis. Time series and hip-knee coordination analyses were performed using statistical parametric mapping and descriptive techniques.ResultsSignificantly lower single-leg hop distance was noted in ACLr group (158.10 cm) compared to control group (178.38 cm). Although the hip and knee moments showed significant differences between four directions (p < 0.01), no group effect was observed (p > 0.05). Statistical parametric mapping showed significant differences (p ≤ 0.05) between groups for hip abduction and coordinate plot of hip and knee joints. Athletes with ACLr demonstrated a higher velocity of hip adduction. Time-series analysis revealed differences in coordination between groups for frontal hip and knee motion.ConclusionsAthletes with ACLr landed with poor hip adduction control and stiffer knee on the involved side. Multi-directions landing should be considered over the entire time series, which may facilitate improved movement quality and return to sports in athletes with ACLr.

Reliability of Spatiotemporal Characteristics During Single-Legged Hop and Bilateral Drop Jump Tasks Using an Instrumented Pressure Walkway.

Single-legged hop tests have been widely used to assess performance-based outcomes after anterior cruciate ligament (ACL) reconstruction. Traditional single, triple, or 6-meter (6m) timed hop tests only measure distance or time as the principal variables, neglecting other variables, such as individual hop distances within a series of hops, flight time, and stance time. The development of portable instrumented pressure walkways has made it possible to collect parameters such as hop velocity, flight time, stance time, distance, and pressure outside of a laboratory setting. However, the reliability of instrumented pressure walkways in measuring spatial and temporal variables during single-legged hop tests is unknown. This study aimed to determine if the Zeno walkway can reliably measure spatiotemporal (ST) characteristics of hop tests. Cross-Sectional Study. Individuals (n=38) in this cross-sectional study performed single, triple, and 6m hop tests on a pressure-sensitive Zeno walkway. Twenty-one participants completed follow-up testing between one and 14 days later. Intraclass correlation coefficients (ICC(3,k)) were used to assess test-retest reliability of ST variables. The accuracy of vertical jump height and 6m hop timing were also measured. All ST variables demonstrated excellent test-retest reliability (ICC > 0.86) with small minimal detectable change (MDC) values during single-legged hop tests. Six-meter hop time and jump height during a bilateral drop jump were also accurately measured by the walkway. An instrumented pressure walkway is a novel tool to reliably assess non-traditional parameters of clinically relevant hop and jump tests such as flight time, stance time, and jump height after lower extremity injury, surgery, and rehabilitation. 3b.

Validation of OpenCap: A low-cost markerless motion capture system for lower-extremity kinematics during return-to-sport tasks

Low-cost markerless motion capture systems offer the potential for 3D measurement of joint angles during human movement. This study aimed to validate a smartphone-based markerless motion capture system’s (OpenCap) derived lower extremity kinematics during common return-to-sport tasks, comparing it to an established optoelectronic motion capture system. Athletes with prior anterior cruciate ligament reconstruction (12–18 months post-surgery) performed three movements: a jump-landing-rebound, single-leg hop, and lateral-vertical hop. Kinematics were recorded concurrently with two smartphones running OpenCap’s software and with a 10-camera, marker-based motion capture system. Validity of lower extremity joint kinematics was assessed across 437 recorded trials using measures of agreement (coefficient of multiple correlation: CMC) and error (mean absolute error: MAE, root mean squared error: RMSE) across the time series of movement. Agreement was best in the sagittal plane for the knee and hip in all movements (CMC > 0.94), followed by the ankle (CMC = 0.84–0.93). Lower agreement was observed for frontal (CMC = 0.47–0.78) and transverse (CMC = 0.51–0.6) plane motion. OpenCap presented a grand mean error of 3.85° (MAE) and 4.34° (RMSE) across all joint angles and movements. These results were comparable to other available markerless systems. Most notably, OpenCap’s user-friendly interface, free software, and small physical footprint have the potential to extend motion analysis applications beyond conventional biomechanics labs, thus enhancing the accessibility for a diverse range of users.

Single Leg Hop Performance After Anterior Cruciate Ligament Reconstruction: Ready for Landing but Cleared for Take-Off?

While the landing phases of the single-leg hop for distance (SLHD) are commonly assessed, limited work reflects how the take-off phase influences hop performance in patients with anterior cruciate ligament reconstruction (ACLR). To compare trunk and lower extremity biomechanics between individuals with ACLR and matched uninjured controls during take-off of the SLHD. Cross-sectional study design. Laboratory setting. 16 individuals with ACLR and 18 uninjured controls. Normalized quadriceps isokinetic torque, hop distance, and respective limb symmetry indices (LSI) were collected for each participant. Sagittal and frontal kinematics and kinetics of the trunk, hip, knee, and ankle, as well as vertical and horizontal ground reaction forces (GRF) were recorded for loading and propulsion of the take-off phase of the SLHD. Those with ACLR had weaker quadriceps peak torque in the involved limb (p=0.001) and greater strength asymmetry (p<0.001) compared to controls. Normalized hop distance was not statistically different between limbs or between groups (p>0.05) and hop distance symmetry was not different between groups (p>0.05). During loading, the involved limb demonstrated lesser knee flexion angles (p=0.030) and knee power (p=0.007) compared to the uninvolved limb, and lesser knee extension moments compared to the uninvolved limb (p=0.001) and controls (p=0.005). During propulsion, the involved limb demonstrated lesser knee extension moment (p=0.027), knee power (p=0.010), knee (p=0.032) and ankle work (p=0.032), anterior- posterior GRF (p=0.047), and greater knee (p=0.016) abduction excursions compared to the uninvolved limb. Between-limb differences in SLHD take-off suggest a knee underloading strategy in the involved limb. These results provide further evidence that distance covered during SLHD assessment can overestimate function and fail to identify compensatory biomechanical strategies.

Addition of anterolateral ligament reconstruction to primary anterior cruciate ligament reconstruction could benefit recovery of functional outcomes

This study aimed to compare functional outcomes sequentially up to 1 year after combined anterior cruciate ligament reconstruction (ACLR) and anterolateral ligament reconstruction (ALLR) and isolated ACLR. Fifty patients who underwent ACLR with versus without ALLR were analyzed at four different time points (preoperatively and 3, 6, and 12 months postoperatively). For the functional outcomes, muscle strength and acceleration time (AT) were measured using an isokinetic dynamometer. Proprioception was evaluated using joint position sense and dynamic postural stability. Patient-reported outcomes were measured using the Tampa Scale for Kinesiophobia (TSK-11) scores. Functional performance was assessed using single-leg hop distance (SLHD) and Limb Symmetry Index. In the operated knees, quadriceps (at 6 months postoperatively, p = 0.003) and hamstring (at 6 and 12 months postoperatively, p < 0.001) strength were significantly higher in the combined ACLR and ALLR group than the isolated ACLR group. The TSK-11 (at 6 and 12 months postoperatively, p < 0.001) was significantly lower in the combined ACLR and ALLR group than the isolated ACLR group. SLHD was significantly higher in the combined ACLR and ALLR group than the isolated ACLR group (at 6 months, p = 0.022 and at 12 months, p = 0.024). The addition of ALLR to primary ACLR yielded better muscle performance, fear of movement, and functional performance than isolated ACLR.

Impact of Surgical Timing on Functional Outcomes after Anterior Cruciate Ligament Reconstruction.

Objectives: Although acute anterior cruciate ligament reconstruction (ACLR) is often avoided because of postoperative joint stiffness, delayed ACLR can lead to a longer recovery time and can have a negative impact on physical function due to detraining. This study aimed to determine the effects of acute ACLR on postoperative outcomes, including muscle strength, performance, and return to sports. Methods: A total of 110 patients who underwent anatomical ACLR using hamstring autografts were included in this study and were divided into three groups: acute (ACLR performed within 2 weeks after ACL injury), 2-6 weeks (ACLR performed between 2 and 6 weeks after injury), and 6-12 weeks (ACLR performed between 6 and 12 weeks after injury). Several parameters were evaluated, including range of motion, knee joint stability, isokinetic knee strength, performance, and return to sports. Results: No significant differences were found in the range of motion or knee joint stability between the groups. The acute group exhibited significantly greater quadriceps strength at 3 months postoperatively than the other groups (p < 0.05). The single-leg hop test showed that 66.7%, 38.7%, and 33.3% of the patients in the acute, 2-6 weeks, and 6-12 weeks groups, respectively, recovered to an LSI of 90% or greater (p = 0.09, Cramer's V = 0.27). All patients in the acute group were able to return to sports (p = 0.14; Cramer's V = 0.28). Conclusions: Acute ACLR is advantageous for the early recovery of strength and performance without adverse events. Acute ACLR may shorten the time spent away from sports activities.

Estimating the Reliability and Validity of the Quadrant Hop Test in the Assessment of the Functional Stability of the Knee.

Background Many sporting activities demand multidirectional skills and movements, emphasizing the importance of various fitness components such as functional stability, strength, power, endurance, and range of motion. These aspects must be thoroughly assessed before athletes can return to sports safely following an injury. Although the single-leg hop test (SHT) is widely used as the gold standard for evaluating joint stability, it has limitations in assessing multidirectional movements. Therefore, further research is necessary to explore whether increasing the dynamicity of the hop test in different directions enhances its sensitivity in assessing knee joint stability across all four directions. The objective of this study was to investigate the applicability of a new functional assessment tool, the quadrant hop test (QHT), for evaluating lower limb functional stability. Methodology One hundred nineteen amateur sportsmen who are in the age group of 18-25 years with a limb symmetry index of the lower limb calculated through SHT of >80% were included. All the participants performed the SHT, a triple hop test (THT), a crossover hop test (CHT), and the QHT on two different days, with two investigators assessing the QHT on different days and then recording the measurements of Hop distance. Results The mean difference between SHT, THT, and CHT with QHT was 4.59%, with a moderate correlation between all the hop tests. The Cronbach's alpha revealed good intra-rater (0.917) and inter-rater reliability (0.912) of the QHT. Conclusion The QHT proves to be a reliable and valid measure for assessing the functional stability of the lower limb and is 4.59% more sensitive than SHT, THT, and CHT in assessing knee stability and in return to sports criteria.

Effects of High-intensity Training and Electrical Stimulation on Pain, Disability, Knee Kinematic and Performance in Patellofemoral Pain: A Randomized Controlled Trial

Patellofemoral pain (PFP) is a widespread problem in athletes who participate in jumping, cutting, and pivoting sports. Forty-four players participated in this study. They were divided into two groups: exercise plus EMS (G1) and exercise without EMS (G2), both with 12 women and 10 men. The exercise performed was 8 weeks of a high-intensity strength program for 45-60 minutes, plus cooling and a warm-up phase. Visual analogue scale (VAS), disability (Kujala patellofemoral score), knee valgus angle (KVA) and single-leg hop (SLH) were tested before (pre-test) and after training (post-test at 8 weeks) using a within-between group analysis (ANOVA 2×2). At baseline, no differences between groups were found (p &gt; 0.05). After the intervention, both groups improved VAS, KVA, SLH (p &lt; 0.001), and disability (p = 0.042). G1 showed more improvements than G2 for VAS (- 63.4 vs - 51.5 %, p = 0.021, 𝜂p2 = 0.13), disability (+ 32.6 vs + 18.4 %, p = 0.001, 𝜂p2 = 0.52), KVA (+ 4.2 vs + 2.2 %, p = 0.016, 𝜂p2 = 0.214) and SLH (+ 12.3 vs + 6.0 %, p = 0.003, 𝜂p2 = 0.20) respectively. No differences were found between the sexes for each group. Despite both interventions being valid, high-intensity strength training combined with EMS improved pain, disability, knee kinematics, and lower extremity performance more than exercise alone in professional handball athletes with PFP. Keywords: Electrical muscle stimulation, Rehabilitation, Musculoskeletal, Knee, Handball players

Effects of Vertical and Horizontal Jumping Asymmetries on Linear and Change-of-Direction Speed Performance of Female Soccer Players

In recent years, along with the remarkable development of women’s soccer, significant attention has been given to the study of asymmetry in lower limbs. However, there is uncertainty about whether and to what extent jumping asymmetries affect the performance of female soccer players. The aims of this study were to examine (a) possible asymmetries in jumping ability and (b) the correlations between asymmetries and performance of female soccer players in 10 m and 30 m speed tests, as well as in change-of-direction speed tests. The study involved 12 adolescent (age: 15.8 ± 0.8 years, body mass: 59.4 ± 7 kg and height: 160.5 ± 5.1 cm) and 10 adult female soccer players (age: 22.3 ± 4.4 years, body mass: 62.2 ± 7.5 kg and height: 165.7 ± 6.1 cm). Pearson’s correlations showed no statistically significant relationships between vertical and horizontal asymmetries and time in 10 m, 30 m and 505 change-of-direction speed tests for adolescent players. In adult players, a significantly high correlation was found between asymmetries in single-leg hop tests (for distance) and time in 505 change-of-direction speed tests (r = 0.68, p &lt; 0.05). Adult players showed higher asymmetry values in vertical and horizontal jump tests, but these asymmetries were not significant (p &gt; 0.05). Practitioners are recommended to implement strength and power training programs, as well as injury prevention protocols, aiming to reduce asymmetries, in order to minimize the risk of injuries, and potentially improve performance of female soccer players in certain fitness tests.