Altered lower extremity joint mechanics occur during the star excursion balance test and single leg hop after ACL-reconstruction in a collegiate athlete

The effects of contralateral limb cross-education training on post-surgical rehabilitation outcomes in patients with anterior cruciate ligament reconstruction: a randomized controlled trial

OBJECTIVE

This study examines whether cross-education training of the healthy limb promotes cross-transfer through central nervous system stimulation, enhancing the function, kinematic parameters, dynamic balance, and plantar pressure of the affected knee joint in patients recovering from postoperative anterior cruciate ligament reconstruction (ACLR).

METHODS

Forty anterior cruciate ligament reconstruction (ACLR) patients, 5-6 weeks postoperatively, were included and randomly assigned to either an experimental group (n = 20) or a control group (n = 20). The experimental group participated in six weeks of cross-education (CE) training in addition to conventional rehabilitation, while the control group received only conventional rehabilitation. Assessment outcomes included knee function (Lysholm score, joint mobility, and surface electromyographic characteristics of the rectus femoris muscle), kinematic parameters (stride length, stride speed, and stride width), dynamic balance (gait line length, single-support line length, and medial-lateral displacements), and plantar pressure (forefoot, midfoot, and hindfoot pressures). The effect of CE training on postoperative ACLR rehabilitation was comprehensively assessed by comparing the pre- and post-intervention changes within each group and the differences between the groups.

RESULTS

Before the intervention, no statistically significant differences were observed between the two groups across all measured parameters (P > 0.05). Following the intervention, significant improvements in knee function, kinematic parameters, balance function, and plantar pressure were observed in both groups, with the experimental group showing significantly more significant improvements (P < 0.05). The Lysholm score, range of motion (ROM), and surface electromyographic activity of the rectus femoris muscle were significantly higher in the experimental group compared to the control group (P < 0.01). Among kinematic parameters, the experimental group demonstrated a significant increase in stride length and reduced stride width, whereas differences in stride speed were not statistically significant (P > 0.05). Regarding balance function, the experimental group exhibited significantly longer gait and single-support line lengths, significantly reducing medial-lateral displacement (P < 0.05). Analysis of plantar pressure revealed significant improvements in forefoot and hindfoot pressures in the experimental group, with a particularly notable increase in hindfoot pressure (P < 0.05). However, changes in midfoot pressure were not statistically significant (P > 0.05).

CONCLUSION

CE training markedly enhanced knee function, kinematic metrics, dynamic stability, and plantar pressure in postoperative ACLR patients providing initial evidence for the prospective utilization of CE theory in rehabilitation. Nonetheless, the fundamental mechanics of its effects remain ambiguous, and variables such as individual differences and neuromuscular adaptation processes may affect training results. Future studies should examine its long-term impacts and uncover potential neuromuscular pathways to establish a solid scientific basis for improving postoperative rehabilitation procedures.

A Longitudinal Case-Control Study of a Female Athlete Preinjury and After ACL Reconstruction: Hop Performance, Knee Muscle Strength, and Knee Landing Mechanics

Athletes with an anterior cruciate ligament (ACL) injury followed by ACL reconstruction (ACLR) often perform various testing to guide return to sport, but preinjury data are rarely available for comparison. This longitudinal case-control study reports absolute value and between-leg symmetry data on maximal performances for single-leg hop height and distance, muscle strength, and side hop landing mechanics of an 18-year-old female soccer athlete collected 5 months before sustaining an ACL injury and again at 10, 13, and 29 months post-ACLR. Her data were compared across test sessions and to cross-sectional data of 15 asymptomatic female athletes.

The Effect of Contralateral Knee Neuromuscular Exercises on Static and Dynamic Balance, Knee Function, and Pain in Athletes Who Underwent Anterior Cruciate Ligament Reconstruction: A Single-Blind Randomized Controlled Trial

CONTEXT

Contralateral training in the early stages after surgery can improve the balance of the reconstructed knee, which is impaired following anterior cruciate ligament reconstruction (ACLR). However, little is known about the neuromuscular cross exercise after ACLR.

OBJECTIVE

To investigate the effects of an 8-week cross exercise on balance and function of the reconstructed knee following ACLR.

DESIGN

A single-blind randomized clinical trial.

PARTICIPANTS

Thirty athletic males who underwent ACLR were randomly divided into intervention (n = 15) and control groups (n = 15).

INTERVENTION

The intervention and control groups received a routine physiotherapy program. In addition, the intervention group performed neuromuscular exercises on the nonoperated limb.

OUTCOME MEASURES

Before and 9 weeks after ACLR, dynamic and static balance, function, and pain in the reconstructed knee were measured by Star Excursion Balance Test (SEBT), stork balance stand test, balance error scoring system (BESS), Lysholm questionnaire, and visual analog scale. Data were analyzed by SPSS using 2-independent sample t test, paired t test, and analysis of covariance.

RESULTS

Between-group comparison showed that, contralateral knee neuromuscular exercises significantly increased in the reaching distance in SEBT in the anterior (P < .001), posterior (P < .001), posteromedial (P = .010), and posterolateral directions (P = .007), decreased the number of errors in 4 stance positions of BESS including single stance on the firm (P ≤ .001) and foam surface (P ≤ .001), and tandem stance on the firm (P = .028) and foam surface (P ≤ .001). It also increased the time of standing of the stork stand test (P = .044) and decreased the pain intensity (P = .014).

CONCLUSION

Neuromuscular exercise of the nonsurgical knee could improve the dynamic and static balance, and pain in the early stages following ACLR in the surgical leg. These findings may be potentially valuable for current rehabilitation protocols.

Is There a Link between Balance and Body Mass Composition in Children and Adolescents?

School-age children are particularly prone to disturbances in body composition, because this is a period of intensive growth and a period in which correct habits are shaped, especially in relation to diet. This is why it is so important to diagnose emerging disorders early so as to implement therapeutic or educational activities. The aim of this study was to assess the relationship between the factors of body mass composition and body mass index (BMI), as well as the balance parameters in children and adolescents. The study group consisted of 1137 children aged 7 to 15. There were 559 girls and 578 boys among the subjects. The study used the Tanita 780 body mass composition analyser and the Zebris stabilometric platform. It was found that girls were characterized by a significantly higher content of adipose tissue (24.37% vs. 20.45%), while boys were characterized by a higher content of lean tissue (32.99% vs. 30.43%), muscle tissue (31.23% vs. 28.86%) and water (24.15% vs. 22.28%). Interestingly, the girls had better balance than their peers in all analyzed parameters (COF TTL.-616.72 vs. 661.50; CEArea-73.63 vs. 112.24; COF HD-3.44 vs. 4.23; COF VD-4.52 vs. 5.12). It turned out that among children in adolescence, a higher adipose tissue content and a higher BMI correlated with a smaller surface area (p < 0.05) defined by the center of gravity and smaller deviations of the center of gravity in the horizontal plane (p < 0.05). Sex and adolescence play an important role in differentiating both body composition and body balance. The results of this study allow us to conclude that children with higher BMI values have better balance. Due to the fact that these conclusions are inconsistent with those of other researchers, it will be worth continuing the research (e.g., on a different population group) in order to confirm the results and to draw far-reaching conclusions.

Running Biomechanics Before Injury and 1 Year After Anterior Cruciate Ligament Reconstruction in Division I Collegiate Athletes

BACKGROUND

Preinjury running biomechanics are an ideal comparator for quantifying recovery after anterior cruciate ligament (ACL) reconstruction (ACLR), allowing for assessments within the surgical and nonsurgical limbs. However, availability of preinjury running biomechanics is rare and has been reported in case studies only.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine if running biomechanics return to preinjury levels within the first year after ACLR among collegiate athletes. We hypothesized that (1) surgical knee biomechanics would be significantly reduced shortly after ACLR and would not return to preinjury levels by 12 months and (2) nonsurgical limb mechanics would change significantly from preinjury.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Thirteen Division I collegiate athletes were identified between 2015 and 2020 (6 female; mean ± SD age, 20.7 ± 1.3 years old) who had whole body kinematics and ground-reaction forces recorded during treadmill running (3.7 ± 0.6 m/s) before sustaining an ACL injury. Running analyses were repeated at 4, 6, 8, and 12 months (4M, 6M, 8M, 12M) after ACLR. Linear mixed effects models were used to assess differences in running biomechanics between post-ACLR time points and preinjury within each limb, reported as Tukey-adjusted P values.

RESULTS

When compared with preinjury, the surgical limb displayed significant deficits at all postoperative assessments (P values <.01; values reported as least squares mean difference [SE]): peak knee flexion angle (4M, 13.2° [1.4°]; 6M, 9.9° [1.4°]; 8M, 9.8° [1.4°]; 12M, 9.0° [1.5°]), peak knee extensor moment (N·m/kg; 4M, 1.32 [0.13]; 6M, 1.04 [0.13]; 8M, 1.04 [0.13]; 12M, 0.87 [0.15]; 38%-57% deficit), and rate of knee extensor moment (N·m/kg/s; 4M, 22.7 [2.4]; 6M, 17.9 [2.3]; 8M, 17.5 [2.4]; 12M, 16.1 [2.6]; 33%-46% deficit). No changes for these variables from preinjury (P values >.88) were identified in the nonsurgical limb.

CONCLUSION

After ACLR, surgical limb knee running biomechanics were not restored to the preinjury state by 12M, while nonsurgical limb mechanics remained unchanged as compared with preinjury. Collegiate athletes after ACLR demonstrate substantial deficits in running mechanics as compared with preinjury that persist beyond the typical return-to-sport time frame. The nonsurgical knee appears to be a valid reference for recovery of the surgical knee mechanics during running, owing to the lack of change within the nonsurgical limb.

Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial

BACKGROUND

We implemented a blood flow restriction resistance training (BFR-RT) intervention during an 8-week rehabilitation programme in anterior cruciate ligament reconstruction (ACLR) patients within a National Health Service setting.

OBJECTIVE

To compare the effectiveness of BFR-RT and standard-care traditional heavy-load resistance training (HL-RT) at improving skeletal muscle hypertrophy and strength, physical function, pain and effusion in ACLR patients following surgery.

METHODS

28 patients scheduled for unilateral ACLR surgery with hamstring autograft were recruited for this parallel-group, two-arm, single-assessor blinded, randomised clinical trial following appropriate power analysis. Following surgery, a criteria-driven approach to rehabilitation was utilised and participants were block randomised to either HL-RT at 70% repetition maximum (1RM) (n = 14) or BFR-RT (n = 14) at 30% 1RM. Participants completed 8 weeks of biweekly unilateral leg press training on both limbs, totalling 16 sessions, alongside standard hospital rehabilitation. Resistance exercise protocols were designed consistent with standard recommended protocols for each type of exercise. Scaled maximal isotonic strength (10RM), muscle morphology of the vastus lateralis of the injured limb, self-reported function, Y-balance test performance and knee joint pain, effusion and range of motion (ROM) were assessed at pre-surgery, post-surgery, mid-training and post-training. Knee joint laxity and scaled maximal isokinetic knee extension and flexion strength at 60°/s, 150°/s and 300°/s were measured at pre-surgery and post-training.

RESULTS

Four participants were lost, with 24 participants completing the study (12 per group). There were no adverse events or differences between groups for any baseline anthropometric variable or pre- to post-surgery change in any outcome measure. Scaled 10RM strength significantly increased in the injured limb (104 ± 30% and 106 ± 43%) and non-injured limb (33 ± 13% and 39 ± 17%) with BFR-RT and HL-RT, respectively, with no group differences. Significant increases in knee extension and flexion peak torque were observed at all speeds in the non-injured limb with no group differences. Significantly greater attenuation of knee extensor peak torque loss at 150°/s and 300°/s and knee flexor torque loss at all speeds was observed with BFR-RT. No group differences in knee extensor peak torque loss were found at 60°/s. Significant and comparable increases in muscle thickness (5.8 ± 0.2% and 6.7 ± 0.3%) and pennation angle (4.1 ± 0.3% and 3.4 ± 0.1%) were observed with BFR-RT and HL-RT, respectively, with no group differences. No significant changes in fascicle length were observed. Significantly greater and clinically important increases in several measures of self-reported function (50-218 ± 48% vs. 35-152 ± 56%), Y-balance performance (18-59 ± 22% vs. 18-33 ± 19%), ROM (78 ± 22% vs. 48 ± 13%) and reductions in knee joint pain (67 ± 15% vs. 39 ± 12%) and effusion (6 ± 2% vs. 2 ± 2%) were observed with BFR-RT compared to HL-RT, respectively.

CONCLUSION

BFR-RT can improve skeletal muscle hypertrophy and strength to a similar extent to HL-RT with a greater reduction in knee joint pain and effusion, leading to greater overall improvements in physical function. Therefore, BFR-RT may be more appropriate for early rehabilitation in ACLR patient populations within the National Health Service.

Measuring only hop distance during single leg hop testing is insufficient to detect deficits in knee function after ACL reconstruction: a systematic review and meta-analysis

Objective

To systematically review the biomechanical deficits after ACL reconstruction (ACLR) during single leg hop for distance (SLHD) testing and report these differences compared with the contralateral leg and with healthy controls.

Design

Systematic review with meta-analysis.

Data sources

A systematic search in Pubmed (Ovid), EMBASE, CINAHL, Scopus, Web of Science, PEDro, SPORTDiscus, Cochrane Library, grey literature and trial registries, was conducted from inception to 1 April 2018.

Eligibility criteria for selecting studies

Studies reporting kinematic, kinetic and/or electromyographic data of the ACLR limb during SLHD with no language limits.

Results

The literature review yielded 1551 articles and 19 studies met the inclusion criteria. Meta-analysis revealed strong evidence of lower peak knee flexion angle and knee flexion moments during landing compared with the uninjured leg and with controls. Also, moderate evidence (with large effect size) of lower knee power absorption during landing compared with the uninjured leg. No difference was found in peak vertical ground reaction force during landing. Subgroup analyses revealed that some kinematic variables do not restore with time and may even worsen.

Conclusion

During SLHD several kinematic and kinetic deficits were detected between limbs after ACLR, despite adequate SLHD performance. Measuring only hop distance, even using the healthy leg as a reference, is insufficient to fully assess knee function after ACLR.

PROSPERO trial registration number CRD42018087779.