The influence of abnormal hip mechanics on knee injury: a biomechanical perspective

Video Analysis of Anterior Cruciate Ligament Injuries in Male Professional Basketball Players: Injury Mechanisms, Situational Patterns, and Biomechanics

Background

Improving our understanding of the situations and biomechanics that result in an anterior cruciate ligament (ACL) injury in basketball players may support the design of more effective programs to mitigate the risk of injury.

Purpose

To (1) describe the mechanisms, situational patterns, and gross biomechanics (kinematics) of ACL injuries in professional basketball matches using video analysis and (2) document the distribution of ACL injuries according to player position, phase of the match, and location on the court.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 38 ACL injuries in professional male European basketball leagues from the 2013-2014 to 2019-2020 seasons were identified. There were 36 (95%) injury videos analyzed for injury mechanisms and situational patterns, while biomechanical analysis was possible in 32 cases. Overall, 3 independent reviewers evaluated each video. Data according to player position (n = 38), phase of the match (n = 38), and location on the court (n = 36) were evaluated.

Results

More injuries occurred while attacking (n = 25 [69%]) than defending (n = 11 [31%]). There was 1 (3%) direct contact injury, 21 (58%) indirect contact injuries, and 14 (39%) noncontact injuries. Most injuries (83%) occurred during 3 main situations: offensive cut (n = 17 [47%]), landing from a jump (n = 8 [22%]), and defensive cut (n = 5 [14%]). Injuries generally involved knee flexion (with minimal hip/trunk flexion and reduced plantarflexion) in the sagittal plane and knee valgus loading in most cases (75%). A similar number of injuries occurred during the first (53%) and second (47%) halves of the match, with a higher prevalence in the second (37%) and fourth (34%) quarters. Half of the injuries occurred during the first 10 minutes of effective playing time. More injuries occurred in guards (58%), and 73% of all injuries occurred in the scoring zone.

Conclusion

Indirect contact was the main injury mechanism found in male professional basketball players. The offensive cut was the most common situational pattern. Biomechanical analysis confirmed a multiplanar mechanism, with knee loading in the sagittal plane accompanied by dynamic valgus. More injuries occurred in the first 10 minutes of a player's effective playing time, within the scoring zone, and among guards.

Three-dimensional kinematics of the trunk, pelvis, hip, and knee during the single-leg squat and hip torque in subjects with isolated patellofemoral osteoarthritis compared to individually matched controls: Preliminary results

Objectives: This study aimed to compare three-dimensional kinematic of the trunk, pelvis, hip, and knee during the single-leg squat and hip torque in individuals with and without isolated patellofemoral osteoarthritis (PFOA). Patients and methods: This cross-sectional study evaluated trunk, pelvis, hip, and knee kinematics at 30°, 45°, and 60° knee flexion during the single-leg squat using the Vicon motion capture and analysis system, the Nexus System 2.1.1, and 3D Motion Monitor software. Sixteen individuals (8 males, 8 females; mean age: 49.3±6.2 years; range 40 to 61 years) participated in the study, of which eight were PFOA patients and eight were healthy controls. Isometric hip abductor, extensor, and external rotator torques were evaluated using a handheld dynamometer. Results: The PFOA group exhibited greater hip adduction at 30° (p=0.008), 45° (p=0.005), and 60° (p=0.008) knee flexion in the descending phase of the single-leg squat, as well as at 60° (p=0.009) and 45° (p=0.03) knee flexion in the ascending phase. No significant differences were found between groups for other kinematic variables (p>0.05). The PFOA group exhibited lower isometric hip abductor (p=0.02), extensor (p <0.001), and external rotator (p=0.007) torques. Conclusion: Individuals with PFOA exhibited excessive hip adduction that could increase stress on the lateral patellofemoral joint at 30°, 45°, and 60° knee flexion during the single-leg squat and exhibited weakness of the hip abductors, extensors, and external rotators in comparison to healthy controls.

Effects of hip abductor with external rotator strengthening versus proprioceptive training on pain and functions in patients with patellofemoral pain syndrome: A randomized controlled trial

BACKGROUND

Strengthening the hip muscles, particularly the abductors and rotators, has been reported beneficial for treating Patellofemoral pain syndrome (PFPS). Proprioceptive training (PT) is also shown to improve musculoskeletal pain and function in PFPS. The most appropriate treatment from these 2 is unclear. This study aimed to compare the effects of hip abductors and external rotator strengthening exercises along with conventional physical therapy (CPT) vs the proprioceptive training of the knee along with CPT in patients with PFPS.

METHODS

Forty-five participants were divided into 3 groups, experimental group 1 (EG 1), experimental group 2 (EG 2), and control group (CG), with fifteen participants in each group. EG 1 received hip abductor and external rotator strengthening exercises in addition to CPT. EG 2 received proprioceptive training and CPT. CG received CPT alone. Intervention programs lasted for 4 weeks. The pain was measured by Kujala Anterior Knee Pain Scale (AKPS). The study was registered retrospectively in the protocol registration and results system (clinicaltrials.gov, ID: NCT05698797 on 26/01/2023).

RESULTS

AKPS scores significantly (P < .001) improved in all 3 groups. A significant (P < .05) difference was also observed between all 3 groups. The greatest improvement was observed in EG 1, followed by EG 2 and CG.

CONCLUSION

The addition of hip abductor and external rotator strengthening exercises to a 4-week CPT program showed a more significant improvement in AKPS scores than the addition of proprioceptive training in patients with PFPS.

Exploring the relationship between core stability and vertical jump in recreationally active male college students based on a suite of novel core stability assessments

Various assessments have contributed to inconsistent findings regarding the correlation between core stability and vertical jumps. Therefore, this study aimed to re-examine this correlation based on novel core stability assessments. Twenty-one recreationally active male college students (age, 21.7 ± 2.1 years; stature, 174.9 ± 6.7 cm; body mass, 67.7 ± 7.8 kg; leg length, 88.9 ± 4.8 cm; arm length, 87.8 ± 4.0 cm) participated in this experiment. Core stability was divided into static and dynamic core stabilities, with the static core stability measured using the Eight-Level Prone Bridge and Five-Level Side Bridge tests and the dynamic core stability measured using the Y Balance Test (YBT). These tests comprehensively evaluate core stability as it is defined. Kinematic and kinetic data on vertical jumps were collected to provide process information beyond the outcome performance. Subsequently, these data were correlated with core stability for a deeper insight into the relationship between core stability and the process and outcome performance of vertical jumps. The main results revealed that the Eight-Level Prone Bridge demonstrated moderate to substantial correlations with Δ F y ‾ , Δ I y , Δ D l e f t k n e e z , and Δ D l e f t a n k l e y (-0.62 ≤ r ≤ 0.52); the Five-Level Side Bridge exhibited moderate correlations with Δ F x ‾ , Δ F y ‾ , Δ I x , Δ I y , Δ D l e f t k n e e z , and Δ D l e f t a n k l e y (-0.52 ≤ r ≤ 0.59); YBT displayed moderate correlations with F z ‾ , F l e f t z ‾ , Δ D l e f t a n k l e y , Δ D r i g h t a n k l e y , Δ D l e f t a n k l e z , Δ D r i g h t a n k l e z , NΔ T a n k l e y ‾ , and N T l e f t a n k l e z ‾ (-0.54 ≤ r ≤ 0.54) during the propulsive phase of vertical jumps. However, no significant correlations were observed between static/dynamic core stability and jumping height. Therefore, individuals with greater core stability should experience improved process performance (better movement quality), although this benefit is ineffective in translating into jumping height improvement due to impaired explosive features. Coaches may consider core stability in training to trigger an improved process performance of the vertical jump when the technique is the key issue to be solved, although future studies are required to verify this further.

Relationship between coordination variability and Osgood-Schlatter disease in male junior youth soccer players -cross-sectional study using an inertial measurement unit

BACKGROUND

Osgood-Schlatter disease is a common overuse injury, and motor coordination is discussed as a risk factor; however, no reports have examined motor coordination in young soccer players with Osgood-Schlatter disease. This study aimed to investigate the difference in motor coordination between Osgood-Schlatter disease-affected and non-affected soccer players on a junior youth soccer team.

METHODS

This cross-sectional study investigated 35 young soccer players of 12-15 years of age, who completed a self-administered questionnaire covering general information, injury history, and athletic experience. An inertial measurement unit was attached to the participant's thoracic spine, lumbar spine, pelvis, thigh, and lower leg. The sagittal plane tilt angle of each body segment during squatting was analyzed. The continuous relative phase was calculated using the sagittal plane tilt angle. The mean absolute relative phase and continuous relative phase variabilities were calculated and compared between Osgood-Schlatter disease-affected and non-affected players.

FINDINGS

The sagittal plane tilt angle of each body segment during static standing and maximum flexion did not differ between the two groups. However, the Osgood-Schlatter disease group had significantly less continuous relative phase variability between the lumbar spine and pelvis (P < 0.01, Cohen's d = 0.91). The Osgood-Schlatter disease group had significantly fewer participants with other sports experience (P = 0.032, φ = 0.36).

INTERPRETATION

Dysfunctional lower trunk and hip muscles may be leading to Osgood-Schlatter disease. It is suggested that a variety of physical activities should be performed in the junior age group to allow players to acquire a variety of movement patterns.

Acute Effect of Dynamic and Gluteal Resistance Exercise Warm-up Protocols on Jump Landing Mechanics in College-Aged Females

ABSTRACT

Rauseo, ML, Feairheller, DL, LaRoche, DP, and Cook, SB. Acute effect of dynamic and gluteal resistance exercise warm-up protocols on lower-extremity jump landing mechanics in college-aged females. J Strength Cond Res 38(2): 259-265, 2024-Inadequate neuromuscular control of the femur by the gluteal musculature is associated with noncontact and overuse injuries to the knee. Acute bouts of resistance exercises targeting the gluteal musculature can be prescribed as part of a warm-up protocol with the goal of improving subsequent neuromuscular control and performance. The purpose of this study was to determine the effect that a warm-up protocol including moderate-intensity gluteal resistance exercises (GRE) has on single leg jump landing biomechanics. Seventeen healthy, college-aged, recreationally active females (mean ± SD ; age = 21.4 ± 1.9 years; height = 166.9 ± 5.7 cm; body mass = 62.5 ± 7.4 kg) performed 3 single leg hop trials per leg after completing no warm-up (CON), a dynamic warm-up (DWU), and a dynamic warm-up with gluteal resistance exercises (DWU + GRE) across 3 laboratory visits. Lower extremity kinetic and kinematic variables were assessed during single leg hops from the point of initial foot contact to deepest knee flexion. Biomechanical differences between dominant and nondominant limb landings were also assessed. Dominant limb hip internal rotation angle after DWU + GRE (2.03 ± 9.92°) was significantly greater ( p ≤ 0.05) compared with CON (-3.36 ± 7.74°). Peak knee adduction moment (56.8%), peak knee flexion angle (5.7%), and peak knee external rotation angle (17.0%) were significantly greater ( p ≤ 0.017) in the dominant limb, compared with the nondominant limb, across warm-up protocols. The combined DWU + GRE warm-up protocol did not have a substantial impact on landing biomechanics. Clinicians prescribing GRE before activity should not expect significant changes in movement patterns after a single bout.

Is Adding Education to Trunk and Hip Exercises Beneficial for Patellofemoral Pain? A Randomized Controlled Trial

OBJECTIVE

To investigate the effect of adding education to trunk and hip exercises in patients with patellofemoral pain (PFP).

DESIGN

A randomized controlled trial.

SETTING

Research laboratory.

PARTICIPANTS

Sixty patients with PFP (N=60) were randomly assigned to either an experimental group (education followed by trunk and hip exercises, n=30) or a control group (trunk and hip exercises, n=30).

INTERVENTIONS

Both groups received 8 weeks of trunk and hip exercises, while patients in the experimental group participated in 3 prior education sessions.

MAIN OUTCOME MEASURES

The primary outcome was pain; secondary outcomes were pain catastrophizing, kinesiophobia, function, and muscle strength. Outcomes were assessed at baseline, after 8 weeks (post-intervention), and 3 months post-intervention (follow-up).

RESULTS

No significant between-group differences were observed for pain outcome post-intervention. The experimental group showed superiority over the control group in the improvement of pain catastrophizing (mean difference: -2.32; 95% confidence interval [CI] -1.059 to 0.028) and kinesiophobia (mean difference: -3.56; 95% CI -1.067 to -0.035) at post-intervention. In the experimental group, improvements were maintained at follow-up assessment for all outcomes, except muscle strength.

CONCLUSION

Adding education to trunk and hip exercises was associated with greater improvements in psychological outcomes than trunk and hip exercises alone after the intervention. Education can be incorporated when designing trunk and hip exercises for patients with PFP.

The Correlation between Intersegmental Coordination Variability and Frontal Plane Hip Kinematics during Running in Persons with Patellofemoral Pain

Background

Despite the existing evidence indicating altered hip kinematics as well as the studies showing altered movement coordination variability in persons with patellofemoral pain (PFP), there is no study investigating the correlation between hip joint kinematic and movement coordination variability in persons with patellofemoral pain (PFP).

Objective

This study aims to evaluate the correlation between peak hip adduction and variability of thigh frontal-shank transverse coordination during running in persons with PFP.

Material and Methods

In this cross-sectional correlational study, kinematic data were collected from 34 females (17 with and 17 without PFP) aged 18-35 years during treadmill running at preferred and fixed speeds, each for 30 s. The continuous relative phase method was used to calculate the coordination of thigh frontal-shank transverse. To calculate the deviation phase as the variability of intersegmental coordination, the standard deviation of the ensemble continuous relative phase curve points was averaged. The parameters of interest were peak hip adduction and coordination variability of thigh frontal-shank transverse. The Pearson Correlation Coefficient (r) was used to calculate the correlation between the variables.

Results

The Pearson correlation coefficient showed a significant negative correlation between the peak hip adduction angle and variability of thigh frontal- shank transverse during running at both fixed (r=-0.553, P<0.05) and preferred (r=-0.660, P<0.01) speeds in persons with PFP while the control group showed a small nonsignificant correlation (r<0.29, P>0.05).

Conclusion

The results indicated that greater adduction of the hip joint in persons with PFP during running is contributed to lesser variability of thigh frontal-shank transverse.

Effectiveness of a specific strength program of the gluteus maximus muscle to improve dynamic postural control in female basketball players. A randomized controlled trial

BACKGROUND

Basketball is a team sport in which players perform multidirectional movements, jumps and landings, experiencing abrupt accelerations and decelerations and numerous changes of rhythm. In this sport, speed and intensity are two key factors that are associated with an increased risk of injury. The aim of this randomized controlled trial was to determine the effectiveness of a specific gluteus maximus strength programme as preventive work for young female basketball players, to improve dynamic postural stability and to observe its impact in the rate of lower limb injuries, vertical jump, dynamic knee valgus and pain.

RESEARCH QUESTION

Is effective a strength programme to improve dynamic postural stability, vertical jump and dynamic valgus in female basketball players?

METHODS

A hundred and thirteen female basketball players that play in professional clubs were recruited, reaching the final stage 92 (46 per group). One group (CG) received conventional injury prevention training while the experimental group (EG) added to the conventional team prevention program, a gluteus maximus strength programme of 5 months composed of 4 exercises/2 days per week/2 sets of 10 repetitions per leg.

RESULTS

The total injury incidence decreased from 0.33 to 0.16 cases (control group pre=0.43 to post=0.14 cases, EG pre=022 to post=0.19). The EG improved overall (p = 0.000), posterior (p = 0.001), posteromedial (p = 0.001) and posterolateral (p = 0.000) dynamic stability of the right leg; anterior (p = 0.024), medial (p = 0.07) and posteromedial (p = 0.01) of the left leg. Both groups improved vertical jump (GC: p = 0.045 and GE: p = 0.000). There was no significant improvement in pain or valgus.

SIGNIFICANCE

This strength programme is effective in improving dynamic stability especially of the dominant leg and jump height.

Persons with patellofemoral pain exhibit altered hip abductor muscle recruitment while performing hip abductor exercises

INTRODUCTION

Strengthening of the hip abductors has been advocated for persons with patellofemoral pain (PFP). It is not clear if these individuals activate the hip abductor muscles appropriately to achieve the desired therapeutic effects.

OBJECTIVE

To compare activation of the hip abductor muscles between persons with and without PFP during the performance of hip abductor exercises.

METHODS

Thirty-two individuals participated (12 with PFP and 20 without PFP). The average age (± standard deviation) was 29.7 ± 5.9 years for the PFP group and 28.1 ± 6.9 for the control group. Electromyographic (EMG) signals from the gluteus medius (GMED), superior gluteus maximus (SUP-GMAX), and tensor fascia lata (TFL) were obtained using fine-wire electrodes while participants performed 11 different exercises. Normalized EMG activity of each muscle was compared between groups across all exercises.

RESULTS

When averaged across all exercises, persons with PFP exhibited significantly greater EMG activity of TFL (mean = 25.3% MVIC; 95% CI = 19.2, 31.3) compared to those without PFP (mean = 17.6% MVIC; 95% CI = 12.8, 22.4) and significantly lower EMG activity of SUP-GMAX (mean = 16.4% MVIC; 95% CI = 11.0, 22.0) compared to those without PFP (mean = 25.4% MVIC; 95% CI = 21.0, 29.8). Persons with PFP exhibited lower EMG activity of GMED, but only for 3 out of the 11 exercises evaluated (hip abduction, hip hike, step-up).

CONCLUSION

Compared to persons without PFP, those with PFP exhibited activation differences during the performance of exercises used to target the hip abductors. Our results highlight the need for activation training prior to the initiation of strengthening exercises to achieve desired therapeutic effects.

Clinical Determinants of Knee Joint Loads While Sidestepping: An Exploratory Study With Male Rugby Union Athletes

Background

While several clinical factors have independently been linked to anterior cruciate ligament (ACL) injury risk factors, their collective impact on knee loading during the sidestep maneuver is unknown. To better understand these factors, we assessed the relationship between strength, balance, and sprint kinetics and external knee abduction moments during sidestepping on each leg.

Methods

Sixteen male academy-level rugby union athletes (age, 20 ± 3 years; body-height, 186 ± 9 cm; body-mass, 99 ± 14 kg) were bilaterally assessed in single-leg: isokinetic concentric and eccentric knee and concentric hip strength, balance at 2 difficulty levels, vertical and horizontal force production during maximal sprinting, and 3-dimensional motion capture while sidestepping on the preferred and non-preferred leg. A hierarchical multiple regression analysis based on this theoretical approach of the mechanics of ACL injury risk was performed.

Results

When sidestepping on the preferred leg, larger abduction moments were explained by less concentric hip extension strength and vertical force production during maximal sprinting (R 2 = 41%; ES = 0.64); when sidestepping on the non-preferred leg, larger abduction moments were explained by more concentric hip flexion strength (R 2 = 8%; ES = 0.29). Larger symmetry scores between the legs (representing greater abduction moments) were explained by more horizontal force production during maximal sprinting and less eccentric knee flexion strength (R 2 = 32%; ES = 0.56).

Conclusions

Independently, the preferred and non-preferred legs contribute to increased knee abduction moments via unique distributions of strength and/or sprint kinetics. The allocations of strength and sprint kinetics appear interrelated through weaker posterior muscular strength and may be modifiable through a targeted strength training approach.

Lumbopelvic manipulation alone versus combined with dry needling in physically active patients with patellofemoral pain syndrome: A randomized clinical trial

INTRODUCTION

Patellofemoral pain syndrome (PFPS) is prevalent in physically active people. The multifactorial nature of PFPS necessitates multimodal treatment for this condition. The present study aimed to compare the efficacy of lumbopelvic manipulation alone versus manipulation plus dry needling in physically active patients with PFPS.

METHOD

Thirty patients (18 women and 12 men) with a diagnosis of PFPS entered this randomized controlled clinical trial and were divided into two groups: lumbopelvic manipulation alone or lumbopelvic manipulation plus dry needling. The interventions were applied for 3 sessions every other day. Dry needling was performed on the quadratus lumborum and gluteus medius muscles. Pain intensity, Kujala score and side-plank time were recorded at baseline, post-intervention and 1 month after the intervention.

RESULTS

The results of Friedman's test showed statistically significant differences in pain and function in participants during the study period, and post hoc tests revealed differences between the two groups in behavior of the marginal means (p < 0.001).

CONCLUSION

The use of lumbopelvic manipulation plus dry needling in the quadratus lumborum and gluteus medius muscles may be more effective than manipulation alone in alleviating pain and promoting function in physically active patients with PFPS.

Strengthening the Intrinsic Muscles of the Foot and Its Action on Foot Posture and Self-Reported Function in Individuals With Lower Limb Injuries: Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this study was to systematically review the influence of the intrinsic foot musculature on lower limb injuries, with regard to improving foot posture and self-reported function, and to point out the biomechanical effects of strengthening the intrinsic foot musculature.

METHODS

A comprehensive literature search using National Library of Medicine (Medline-PubMed), Scopus, Web of Science, Pedro, SportDiscus, and Cochrane was undertaken.

SELECTION CRITERIA

A literature search was peformed using: Clinical trials of patients with injuries in the lower limbs, and with alterations in the intrinsic musculature of the foot were included and published in the period up to and including April 2023.

DATA SYNTHESIS

Data analysis was measured as standardized mean difference and confidence interval was set at 95%. Random effects model was used.

RESULTS

A total of 1,051 studies were found, but, after evaluation, only 4 were included in the present study. The effect of intrinsic foot musculature strengthening improved medial longitudinal arch height in studies included in the meta-analysis (P < .00001).

CONCLUSION

Based on this systematic review, it is possible to conclude that increasing the strength of intrinsic foot muscles proved to be effective in promoting positive biomechanical changes in the longitudinal arch of the foot of these patients.

Joint knee loads during squat with constant or variable resistance in males. A clinical trial

BACKGROUND

In the squat movement, the use of constant resistance (CR) generates greater compression and shear forces close to 90° of knee flexion, increasing joint overload. However, when used variable resistance (VR) there is no consensus about the effect of knee joint load. The aim of this study was to compare knee torques using constant or variable resistance during the squat exercise.

METHODS

Twenty-one healthy male subjects (mean age, 24 [SD, 3] years; height, 1.76 [SD, 0.04] m), who practice squats during strength training routine. Were simultaneously record data from the platform force and tridimensional kinematic to obtain torques around knee. 15 repetitions were performed up to maximum knee flexion with the use of variable (RV) or constant (CR) resistance in a single session.

RESULTS

Significant differences regarding the angles only in the sagittal plane at the end of the ascending phase of the squat, with less knee extension in the VR condition. In the sagittal and frontal planes, lower values of extensor and abductor torque were found in the VR condition at the angles of greater knee flexion.

CONCLUSION

The use of variable resistance compared to constant resistance seems to be an alternative to be considered when the objective is to minimize the internal loads on the knee joint in exercises such as the squat in amplitudes of greater flexion. This study indicated that VR helps subjects who are learning the squat movement, enabling the application of this knowledge in physical therapy or physical training clinics.

Effect of augmented feedback on classical ballet jump kinematics: A single-blind randomized controlled trial

BACKGROUND

Augmented feedback strategies have been demonstrated to enhance jump-related biomechanics. Nevertheless, its effect on classical ballet is still unknown. The purpose of this study was to investigate whether a multimodal augmented feedback session is effective for improving lower limb and trunk kinematics during a classical ballet single-leg jump.

METHODS

In a single-blind randomized controlled trial, 36 amateur classical ballet dancers were randomly assigned to either a control group (n = 18) to receive a brief warm-up session, or an augmented feedback group (n = 18) to receive, in addition to a brief warm-up session, a combined visual feedback session associated with verbal instruction. Hip kinematics in the frontal and transversal planes and knee and trunk kinematics in the frontal plane were analysed at baseline, immediate post-intervention, and one-week post-intervention. Intervention effects were analysed using a two-way, mixed model, repeated-measures analysis of variance.

RESULTS

No interaction effects were observed, indicating that a single session of multimodal augmented feedback was insufficient to improve lower limb and trunk kinematics during a classical ballet single-leg jump in amateur classical ballet dancers.

CONCLUSION

A single session of multimodal augmented feedback should not be used as the sole component in prevention programs intended to improve jump-related kinematics in amateur classical ballet dancers.

Optimising the Early-Stage Rehabilitation Process Post-ACL Reconstruction

Outcomes following anterior cruciate ligament reconstruction (ACLR) need improving, with poor return-to-sport rates and a high risk of secondary re-injury. There is a need to improve rehabilitation strategies post-ACLR, if we can support enhanced patient outcomes. This paper discusses how to optimise the early-stage rehabilitation process post-ACLR. Early-stage rehabilitation is the vital foundation on which successful rehabilitation post-ACLR can occur. Without high-quality early-stage (and pre-operative) rehabilitation, patients often do not overcome major aspects of dysfunction, which limits knee function and the ability to transition through subsequent stages of rehabilitation optimally. We highlight six main dimensions during the early stage: (1) pain and swelling; (2) knee joint range of motion; (3) arthrogenic muscle inhibition and muscle strength; (4) movement quality/neuromuscular control during activities of daily living (5) psycho-social-cultural and environmental factors and (6) physical fitness preservation. The six do not share equal importance and the extent of time commitment devoted to each will depend on the individual patient. The paper provides recommendations on how to implement these into practice, discussing training planning and programming, and suggests specific screening to monitor work and when the athlete can progress to the next stage (e.g. mid-stage rehabilitation entry criteria).

The knee kinematic patterns and associated factors in healthy Thai adults

BACKGROUND

Reference values for normal knee kinematics were limited in Asian population and were influenced by race and other factors. This study was aimed to establish the reference values and identify the factors associated with knee kinematics in healthy Thai adults, aged 18-40 years.

METHODS

A retrospective cohort study was conducted between 2016 and 2020. Healthy Thai adults aged 18-40 years old with body mass index (BMI) between 18.5 and 24.9 kg/m2 were included. All eligible participants were attached with reflective markers. Their walking was captured by 8-digital cameras, and assessed by motion analysis software. The primary outcomes were average knee kinematic data (degrees) in three dimensional planes as valgus-varus, flexion-extension, and internal-external rotation. Paired t-test and multiple linear regression were applied to compare the outcomes and to determine their associated factors.

RESULTS

Ninety-eight participants (60 females and 38 males) were included with mean age 28.5 ± 5.4 years, and BMI 21.1 ± 2.0 kg/m2. Knee kinematics showed slight adduction during the swing phase, flexion during the stance phase, and obvious external rotation throughout the gait cycle, with a peak of 30-31 degrees during mid-swing. Right knee was significantly more adducted, flexed and externally rotated than the left side, particularly at mid-stance (P = 0.047, 0.017, and < 0.001, respectively). Females had more knee abduction, flexion and external rotation than males. Age, sex, and BMI were significantly correlated with knee abduction at terminal stance (correlation coefficient - 0.12, 95% confidence interval (CI) -0.23, -0.01; -1.37, 95%CI -2.54, -0.20; and - 0.32, 95%CI -0.61, -0.39, respectively), and rotation at mid-swing (correlation coefficient - 0.36, 95%CI -0.69, -0.02; -7.37, 95%CI -10.82, -3.92; and 0.89, 95%CI 0.01, 1.78, respectively).

CONCLUSION

Knee kinematics demonstrates external tibial rotation throughout the gait cycle, significant side differences, and are associated with age, sex, and BMI. Reference values from this study will be useful for functional gait assessment in healthy Thais. However, further comprehensive knee kinetic study including spatio-temporal parameter is recommended.

External weight mass and carrying position influence peak patellar tendon force and patellofemoral joint contact force independently during forward lunge

BACKGROUND

The forward lunge is a common exercise in the rehabilitation of patellar tendinopathy and patellofemoral pain syndrome. External weights are frequently used to increase the peak patellar tendon force and patellofemoral joint contact force during this exercise. The weight's position might influence this relationship. The objective of this study was to investigate the combined effect of an external weight's mass and carrying position on the peak patellar tendon force and patellofemoral joint contact force during a forward lunge.

METHODS

Ten healthy individuals performed forward lunges holding external weights between 0.1 and 0.3 times body mass either in one hand at the ipsilateral or contralateral side of the leading leg, or in two hands at the side or in front of the trunk. Three-dimensional kinematic data and ground reaction forces were collected and peak patellar tendon force and patellofemoral joint contact force were calculated using musculoskeletal modelling. Two-way repeated measures ANOVA's determined the main effects for the external weight's mass and position as well as their interaction effect.

FINDINGS

Increasing the mass of the external weights increased both the peak patellar tendon force and patellofemoral joint contact force linearly and at the same rate in all positions. Both peak forces were larger in the one-hand ipsilateral and two-hand side positions.

INTERPRETATION

An external weight's mass and position both influence the peak patellar tendon force and patellofemoral joint contact force during a forward lunge. The rate of increase in peak forces with increasing mass was similar for all weight-carrying positions.

Effectiveness of Interventions Aimed at Changing Movement Patterns in People With Patellofemoral Pain: A Systematic Review With Network Meta-analysis

OBJECTIVE: To summarize the effectiveness of interventions for changing movement during weight-bearing functional tasks in people with patellofemoral pain (PFP). DESIGN: Systematic review with network meta-analysis (NMA). LITERATURE SEARCH: Medline, Embase, CINAHL, SPORTDiscus, and Cochrane Library were searched from inception up to May 2023. STUDY SELECTION CRITERIA: Randomized controlled trials involving people with PFP and nonsurgical, nonpharmacological interventions on task kinematics were included. DATA SYNTHESIS: NMA was conducted for frontal knee movement data, and pairwise meta-analysis was used to pool data when NMA was not possible. Reduced movements were those changes that indicated movements occurring with less amplitude. The GRADE approach was used to grade the certainty of the evidence. RESULTS: Thirty-seven trials were included (n = 1235 participants). Combining knee/hip exercises with internal feedback had the strongest effect on reducing frontal knee movements (standardized mean difference [SMD] from NMA = -2.66; GRADE: moderate evidence). On pairwise comparisons, the same combination of interventions reduced frontal hip movements (SMD = -0.47; GRADE: moderate evidence) and increased sagittal knee movements (SMD = 1.03; GRADE: moderate evidence), with no effects on sagittal hip movements (GRADE: very low evidence), compared to knee/hip exercises alone. There was no effect for single applications of braces on the frontal knee movement (GRADE: very low evidence) and taping on movements of the knee, hip, and ankle (GRADE: very low to low evidence) compared to no intervention. CONCLUSION: Knee/hip exercises combined with internal feedback techniques may change knee and hip movements in people with PFP. The combination of these interventions can reduce frontal knee and hip movements, and can increase sagittal knee movements. J Orthop Sports Phys Ther 2023;53(12):1-13. Epub 14 September 2023. doi:10.2519/jospt.2023.11956.

A Diagnosis of Vitamin D Deficiency Is Associated With Increased Rates of Anterior Cruciate Ligament Tears and Reconstruction Failure

PURPOSE

To characterize the association between a diagnosis of hypovitaminosis D and primary anterior cruciate ligament (ACL) tear, primary anterior cruciate ligament reconstruction (ACLR), and revision ACLR in different sex and age cohorts.

METHODS

In this retrospective cohort study of the PearlDiver claims database, records were queried between January 1, 2011, and October 31, 2018 for all patients aged 10 to 59 years who received a diagnosis of hypovitaminosis D. Rates of primary ACL tears, primary reconstruction, and revision reconstruction were calculated for sex- and age-specific cohorts and compared with a control of patients without a diagnosis of hypovitaminosis D. Incidence rates for primary ACL injuries were calculated, and multivariable logistic regression was used to compare rates of ACL injury, primary reconstruction, and revision reconstruction while controlling for age, sex, Charlson Comorbidity Index, and several other comorbidities.

RESULTS

Among the 328,011 patients (mean age 41.9 ± 12.6 years, 65.8% female) included in both the hypovitaminosis D and control cohorts, the incidence of ACL tears was 115.2 per 100,000 person-years (95% confidence interval [CI] 107.2-123.7) compared with 61.0 (95% CI 55.2-67.2) in the demographic- and comorbidity-matched control cohort. The study cohort was significantly more likely to suffer an ACL tear over a 1- (aOR 1.67, 95% CI 1.41-1.99, P < .001) and 2-year (aOR 1.81, 95% CI 1.59-2.06, P < .001) period. This trend remained for both male patients at the 1- (aOR 1.66, 95% CI 1.29-2.14, P < .001) and 2-year (aOR 1.68, 95% CI 1.37-2.06, P < .001) mark and female patients at the 1- (aOR 1.69, 95% CI 1.33-2.14, P < .001) and 2-year (aOR 1.80, 95% CI 1.51-2.14, P < .001) mark. Finally, patients with vitamin D deficiency had a significantly increased likelihood of undergoing a revision ACLR within 2 years of a primary reconstruction (aOR 1.28, 95% CI 1.05-1.55, P = .012).

CONCLUSIONS

This study reports an association between patients previously diagnosed with hypovitaminosis D and significantly increased rates of both index ACL tears (81% increase within 2 years of diagnosis) and revision ACLR (28% within 2 years). These results identify a population with increased odds of injury and provide valuable knowledge as we expand our understanding of the relationship between vitamin D and musculoskeletal health.

LEVEL OF EVIDENCE

Level III, retrospective database study.

Sagittal trunk excursion and lumbar repositioning error between female and male patients with patellofemoral pain syndrome

Background

Patellofemoral pain syndrome (PFPS) is a challenging clinical problem affecting adults, adolescents, and physically active populations. PFPS impacts the patient's trunk kinematics in the frontal plane. Previous studies have found gender-based biomechanical differences in patients with PFPS; however, sagittal trunk kinematics during mini-squats and lumbar proprioception in PFPS have not been studied previously.

Objectives

To investigate sagittal trunk excursion (It is defined as the sagittal trunk flexion angle from the start to the end of the mini squat) during mini-squats as well as lumbar repositioning error between individuals with and without PFPS, and determine gender differences in the outcome variables.

Methods

A sample of 56 participants aged 18-25 years was enrolled; 30 with PFPS (13 males, 17 females) and 26 asymptomatic controls (11 males, 15 females). The sagittal trunk excursion during mini-squats was examined by two-dimensional (2D) photographic analysis using Surgimap software. Active lumbar flexion repositioning error was assessed using an isokinetic dynamometer.

Results

For sagittal trunk excursion, no significant main effect of group was observed (p = 0 . 136 ). On the other hand, the main effect was significant for gender (p = 0 . 005 ), as was the interaction effect. Compared to the control group, the PFPS group showed significantly (p = 0 . 01 ) lower sagittal trunk excursion in females than in males during mini-squats. For active lumbar flexion repositioning error, no evidence was found for significant main or interaction effects (p > 0 . 05 ).

Conclusion

Females with PFPS exhibit a more erect sagittal trunk posture than males during mini-squats. Trunk posture should be considered during weight-bearing activities in PFPS, and gender-specific assessment protocols should be developed.

A data mining approach for determining biomechanical adaptations in runners who experienced and recovered from patellofemoral pain syndrome

Patellofemoral pain (PFP) is a common musculoskeletal pain disorder experienced by runners. While biomechanics of those with PFP have been extensively studied, methodological considerations may omit important adaptations exhibited by those experiencing and recovered from pain. Instead of a priori selection of discrete biomechanical variables, a data mining approach was leveraged to account for the high dimensionality of running gait data. Biomechanical data of runners symptomatic for, recovered from, and who had never experienced PFP were collected at the 1st (M1) and 21st (M21) minutes of a treadmill run. Principal component analysis and a logistic regression model were used to classify healthy and symptomatic runners, and a feature ranking process determined the important features. The M1 model achieved an accuracy of 82.76% with features related to knee flexion angle, hip abduction moment and gluteus maximus activation, while the M21 model required an additional nine features to achieve an accuracy of 79.31%. Data for recovered runners were projected onto the models, resulting in five and seven out of twelve symptomatic classifications at M1 and M21, respectively. Following the onset of pain, a greater number of features were required to classify runners with PFP, suggesting they may experience individual pain adaptation strategies.

The relationship between pelvic tilt, frontal, and axial leg alignment in healthy subjects

INTRODUCTION

The relationship between anterior pelvic tilt and overall sagittal alignment has been well-described previously. However, the relationship between pelvic tilt, frontal, and axial leg alignment remains unclear. The aim of the study was to analyze the relationship between pelvic tilt and frontal and axial leg alignment in healthy subjects.

MATERIAL AND METHODS

Thirty healthy subjects (60 legs) without prior surgery underwent standing biplanar long leg radiograph. Pelvic parameters (pelvic tilt, pelvic incidence, sacral slope), hip-knee-ankle angle (HKA), femoral antetorsion and tibial torsion were measured using SterEOS (EOS Imaging) software. EOS was acquired with the feet directing straight anteriorly, which corresponds to a neutral foot progression angle (FPA). The influence of HKA, femoral antetorsion, tibial torsion and gender on pelvic tilt was analyzed in a univariate correlation and multiple regression model.

RESULTS

Sixteen female subjects and 14 male subjects with a mean age of 27.1 years ± 10 (range 20-67) were included. HKA, femoral antetorsion, and tibial torsion correlated with anterior pelvic tilt in univariate analysis (all p < 0.05). Anterior pelvic tilt increased 1.1° (95% CI: 0.7 to 1.5) per 1° of knee valgus (p < 0.001) and 0.5° (95% CI: 0.3 to 0.7) per 1° of external tibial torsion (p < 0.001). Overall, linear regression model fit explained 39% of variance in pelvic tilt by the HKA, femoral antetorsion and tibial torsion (R2 = 0.385; p < 0.001).

CONCLUSION

Valgus alignment and increasing tibial torsion demonstrated a weak correlation with an increase in anterior pelvic tilt in healthy subjects when placing their feet anteriorly. The relationship between frontal, axial leg alignment and pelvic tilt needs to be considered in patients with multiple joint disorders at the hip, knee and spine. Alteration of the frontal, or rotational profile after realignment surgery or by implant positioning might influence the pelvic tilt when the FPA is kept constant.

Different neuromuscular parameters are associated with knee abduction and hip adduction angles during functional tasks

Knee abduction and hip adduction during functional tasks may indicate increased joint injury risk and discriminate between pathological and healthy people. Muscles' neuromuscular variables such as amplitude (EMGAMP) and onset (EMGONSET) have been used to explain kinematics. The study aimed to evaluate the correlation between two EMG variables of seven trunk and lower limb muscles and 3D kinematics during two tasks. Eighteen physically-active women participated in the study. The following variables were obtained during single-leg squat and anterior step-down: (i) EMGAMP and EMGONSET of fibularis longus (FL), tibialis anterior (TA), vastus medialis (VM), biceps femoris (BF), gluteus medius (GMED), ipsilateral (OB_IL) and contralateral (OB_CL) external obliques and (ii) knee abduction and hip adduction angular displacement (initial angle - angle at 60° of knee flexion). Spearman's correlation coefficient was calculated between kinematic and EMG variables. Greater knee abduction was correlated with delayed TAONSET, GMEDONSET and OB_ILONSET during step-down. Greater hip adduction was correlated with lower VMAMP, BFAMP and delayed VMONSET during step-down. Although task-specific, these results suggest that EMGONSET may influence knee abduction, while both EMGONSET and EMGAMP may affect hip adduction. The identification of muscle activation patterns in relation to kinematics may help the development of injury prevention and rehabilitation programs.

Forward step down test - clinical rating is correlated with joint angles of the pelvis and hip: an observational study

BACKGROUND

Clinical methods for assessing quality of movement and functional tests are important to clinicians. Typical deviations from normal kinematics during the clinical test of Forward Step Down Test (FSDT) are pelvic tilt and hip adduction which are associated with the risk of knee pain.

OBJECTIVES

(1) to examine the correlation between clinical assessment of the FSDT and joint angle measurements of pelvis, hip, knee and ankle joints in males and females; (2) to examine the differences in joint angles between individuals rated as good, fair or poor in a FSDT performance test.

METHODS

Ninety-two healthy individuals performing FSDT were video-taped with two-dimensional digital video cameras. The clinical assessment of the FSDT was rated by two experienced physical therapists as good, fair, or poor based on a Crossley et al. (2011) validated scale. Measurements of pelvic drop, hip adduction and knee valgus were taken using Image J software.

RESULTS

Out of 177 lower limbs, 74 (37 in each limb) were clinically rated as "good/fair" (41.80%) while 103 (52 in the dominant leg and 51 in the non-dominant leg) were rated as "poor" (58.19%). No significant differences were observed between dominant and non-dominant legs or between males and females in clinical rating of the FSDT. Pelvic drop angle was significantly higher and hip adduction angle was significantly lower for "poor" clinical rating compared to "good/fair" in both dominant and non-dominant legs (p < 0.001) in males and females. Females demonstrated higher pelvic drop, lower hip adduction and higher knee valgus angles compared with males (p < 0.05).

CONCLUSIONS

This study showed that the clinical rating of FSDT is correlated with joint angle measurements suggesting that this assessment can be utilized in clinical practice. Individuals with poor quality performance of FSDT showed higher pelvic drop and hip adduction movement. Further studies examining different populations with diverse disorders or pathologies are essential.

Is there hip muscle weakness in adults with chronic non-specific low back pain? A cross-sectional study

BACKGROUND

Patients with chronic low back pain may present changes in hip muscles. However, there is still limited and controversial evidence of the association between hip muscle weakness and chronic low back pain and whether this weakness can be assessed with functional tests. The purpose of this study was to assess whether there is hip muscle weakness in patients with non-specific chronic low back pain and whether there is an association between the positive Trendelenburg and Step-Down tests and hip muscle strength.

METHODS

This cross-sectional study included 40 patients with chronic low back pain and 40 healthy participants, assessed in an outpatient clinic in Vitória, Espírito Santo, Brazil. Muscle strength was measured for the hip abductors, adductors, extensors, internal rotators, and external rotators using isometric manual dynamometry and functional stability was measured by the Trendelenburg and Step-Down tests. Muscle strength was compared using the t test for independent samples and the chi-square test. The association between the tests and strength was performed using a binary logistic regression analysis.

RESULTS

Healthy participants showed a statistically significant greater muscle strength for the right hip abductors (mean difference [MD]: 28.1%, 95% confidence interval [CI]: 9.4 to 46.9), right adductors (MD: 18.7%, 95% CI: 6.2 to 31.2), right internal rotators (MD: 8.7%, 95% CI: 1.5 to 15.8), right extensors (MD: 21.1%, 95% CI: 6.2 to 31.2), left abductors (MD: 30.4%, 95% CI: 11.9 to 49), left adductors (MD: 18.4%, 95% CI: 3.7 to 33.2), and left extensors (MD: 21.6%, 95% CI: 6.6 to 36.5). There was no difference between groups for the positive functional tests, and there was no association between the tests and hip muscle strength.

CONCLUSION

Patients with chronic low back pain tend to have hip abductors, adductors, and extensors weakness. Furthermore, the functional tests should not be associated to hip muscle strength in patients with chronic low back pain.

Activation, strength, and resistance: Which variables predict the kinematics of women with and without patellofemoral pain?

INTRODUCTION

Investigating the possible relationship between neuromuscular changes and movement alterations could help to describe the mechanisms underlying patellofemoral pain (PFP).

OBJECTIVE

To investigate whether activation and muscle strength of the trunk and lower limb and muscle resistance of the trunk predict the knee frontal and trunk sagittal kinematics in women with and without PFP.

METHOD

Sixty women (PFP, n = 30; asymptomatic, n = 30) underwent the single-leg squat test to collect electromyographic and kinematic data. Activation of transversus abdominis/internal oblique, gluteus medius (GMed), and vastus medialis oblique (VMO); knee frontal and trunk sagittal angles were analyzed. Participants also underwent maximal isometric tests to determine lateral trunk, hip abductor, and knee extensor torques and performed a lateral trunk resistance test. Multiple regression was used to determine predictive models.

RESULTS

In the PFP group, knee frontal angle (R2 = 0.39, p = 0.001) was predicted by GMed activation (β = 0.23, p = 0.000) and hip abductor torque (β = 0.08, p = 0.022). No variable was able to predict trunk sagittal kinematics in this group. In the asymptomatics, knee frontal angle (R2 = 0.16, p = 0.029) was predicted by hip abductor torque (β = 0.07, p = 0.029), while trunk sagittal angle (R2 = 0.24, p = 0.024) was predicted by VMO activation (β = 0.12, p = 0.016).

CONCLUSION

Kinematics is predicted by the muscles acting in the respective planes, such that hip abductors capacities are related to the knee frontal alignment in both groups, and that of the VMO is related to the trunk sagittal alignment only in asymptomatic women.

Patellar Dislocation: Workup and Decision-Making

Acute patellar dislocation (PD) is usually a problem of adolescents and young adults. In most cases, it is a sports-related injury. It is the result of an indirect force on the knee joint, which leads to valgus and external rotation of the tibia relative to the femur. PD is unlikely to occur on a knee with normal patellofemoral joint (PFJ) anatomy. Acute PD consists of an acute injury of the ligamentous medial patellar stabilizers in the background of factors predisposing to patellar instability. These factors are classified into three groups. The first group refers to the integrity of the ligamentous medial patellar restraints, particularly, the medial patellofemoral ligament (MPFL). The second group refers to an abnormal PFJ anatomy, which renders the patella inherently unstable inside the trochlea. The third group refers to the overall axial and torsional profile of the lower limb and to systemic factors, such as ligament laxity and neuromuscular coordination of movement. PD at a younger age is associated with an increased number and severity of patellar instability predisposing factors and lower stress to dislocate the patella. Acute primary PD is usually treated conservatively, while surgical treatment is reserved for recurrent PD. The aim of treatment is to restore the stability and function of the PFJ and to reduce the risk of patellar redislocation. Surgical procedures to treat patellar instability are classified into non-anatomic and anatomic procedures. Non-anatomic procedures are extensor mechanism realignment techniques that aim to center the patella into the trochlear groove. Anatomic procedures aim to restore the PFJ anatomy (ruptured ligaments, osteochondral fractures), which has been severed after the first incident of PD. Anatomic procedures, especially MPFL reconstruction, are more effective in preventing recurrent PD, compared with non-anatomic techniques. Theoretically, all factors that affect PFJ stability should be evaluated and, if possible, addressed. This is practically impossible. Considering that the MPFL ruptures in almost all PDs, MPFL reconstruction is the primary procedure, which is currently selected by most surgeons as a first-line treatment for patients with recurrent PD. Restoration of the axial and torsional alignment of the lower limbs is also increasingly implemented by surgeons. Non-anatomic surgical techniques, such as tibial-tuberosity osteotomy, are used as an adjunct to anatomic procedures. In the presence of multiple PFJ instability factors, acute MPFL reconstruction may be the treatment of choice for acute primary PD as well. Skeletal immaturity of the patient precludes osseous procedures to avoid premature physis closure and subsequent limb deformity. Unfortunately, restoration of the patient's previous activity level or participation in more strenuous sports is questionable and not easy to predict. In the case of competitive athletes, PD may prevent participation in elite levels of sports.

Influence of self-perceived disability on squatting kinematics in individuals with patellofemoral pain

BACKGROUND

Individuals with patellofemoral pain have a heterogeneous presentation of symptoms during functional tasks; however, biomechanical data often negates self-reported disability. The single leg squat is common in patellofemoral pain literature but may not be a pain provoking task for all individuals. Therefore, our study examined the influence of self-perceived squatting disability in individuals with patellofemoral pain on lower extremity squatting kinematics.

METHODS

We analyzed two-dimensional hip frontal plane projection angle, knee frontal plane projection angle, lateral trunk movement, and pelvic drop in 100 participants, 82 with patellofemoral pain and 18 pain-free controls. Participants with patellofemoral pain were dichotomized based on the level of disability reported during squatting on the anterior knee pain scale. An analysis of variance with post hoc testing was used to compare differences in lower extremity and trunk kinematics between groups, p < 0.05.

FINDINGS

Participants who reported only being able to squat with partial weight bearing had greater hip frontal plane projection angles than those who reported squatting painful each time (p = 0.017). The partial weight bearing group had greater knee frontal plane projection angles compared those who reported pain with repeated squatting and the pain-free group, (p < 0.034). We found no significant differences in lateral trunk motion or pelvic drop between groups.

INTERPRETATION

Individuals with patellofemoral pain who self-reported worse squatting disability had greater hip and knee frontal plane motion compared to individuals with less disability and pain-free controls. Clinicians and researchers should consider specific pain provoking tasks when evaluating and treating patients with patellofemoral pain.

The Effects of Fatigue on the Lower Limb Biomechanics of Amateur Athletes during a Y-Balance Test

The Y-Balance Test (YBT) is a reliable tool for assessing the dynamic balance of athletes' lower limbs. This study aimed to compare the effects of the YBT on lower limb biomechanics before and after fatigue. Sixteen adult male recreational athletes were recruited for the study, and motion capture in combination with a force plate was used to collect kinematic, dynamics, and center of pressure (COP) data of the dominant leg during YBT testing before and after fatigue. Based on the research findings, there were significant statistical differences in the distances reached during the YBT in three directions before and after fatigue. After fatigue, there is a significant decrease in the ROM of the hip and knee joints in all three directions. Also, there is a significant increase in hip joint torque in the anterior- and posterior-lateral directions, while a significant decrease in hip and ankle joint torque is observed in the posterior-medial direction. Moreover, there is an increasing trend in positive and negative joint work for the hip, knee, and ankle joints in all three directions after fatigue. The range of COP displacement also increases following fatigue. The decline in YBT scores demonstrates the detrimental impact of fatigue on the dynamic balance of the lower limbs of adult male amateur athletes. We hope that these results can provide information for athletes and coaches to better understand the effects of fatigue on the dynamic balance of lower limbs, so as to carry out targeted lower limb balance training and prevent sports injuries.

Lower Body Joint Moments during the Golf Swing in Older Adults: Comparison to Other Activities of Daily Living

Golf participation has increased dramatically in the last several years. With this increase in participation, clinicians need better evidenced based strategies to advise those golfers with different pathologies when it is safe to return to the game. Golf teaching professionals also need to understand how to alter golf mechanics to protect injured and/or diseased joints in golfers to allow them to play pain free and avoid further injury. This study used a 3-dimensional link segment model to calculate the net joint moments on the large lower limb joints (knee and hip) during golf (lead and trail leg) and two commonly studied activities of daily living (gait and sit-to-stand) in 22 males, healthy, adult golfers. It also examined the correlations between these knee and hip joint loads and club head speed. The external valgus knee moment and the internal hip adduction moment were greater in the lead leg in golf than in the other activities and were also correlated with club head speed. This indicates a strategy of using the frontal plane GRF moment during the swing. The internal hip extension and knee flexion moment were also greater in the golf swing as compared with the other activities and the hip extension moment was also correlated with club head speed. This emphasizes the importance of hip extensor (i.e., gluteus maximus and hamstring) muscle function in golfers, especially in those emphasizing the use of anterior-posterior ground reaction forces (i.e., the pivoting moment). The golf swing places some loads on the knee and the hip that are much different than the loads during gait and sit-to-stand tasks. Knowledge of these golf swing loads can help both the clinician and golf professional provide better evidence-based advice to golfers in order to keep them healthy and avoid future pain/injury.

Increasing Step Frequency Reduces Patellofemoral Joint Stress and Patellar Tendon Force Impulse More at Low Running Speed

PURPOSE

Patellofemoral pain syndrome and patellar tendinopathy are important running-related overuse injuries. This study investigated the interaction of running speed and step frequency alterations on peak and cumulative patellofemoral joint stress (PFJS) and patellar tendon force (PTF) parameters.

METHODS

Twelve healthy individuals completed an incremental running speed protocol on a treadmill at habitual, increased and decreased step frequency. Peak PFJS and PTF, peak rate of PFJS and PTF development, and PFJS and PTF impulse per kilometer (km) were calculated using musculoskeletal modeling.

RESULTS

With increasing running speed, peak PFJS ( P < 0.001) and PTF ( P < 0.001) and peak rate of PFJS ( P < 0.001) and PTF ( P < 0.001) development increased, whereas PFJS ( P < 0.001) and PTF ( P < 0.001) impulse per km decreased. While increasing step frequency by 10%, the peak PFJS ( P < 0.001) and PTF ( P < 0.001) and the PFJS ( P < 0.001) and PTF ( P < 0.001) impulse per kilometer decreased. No significant effect of step frequency alteration was found for the peak rate of PFJS ( P = 0.008) and PTF ( P = 0.213) development. A significant interaction effect was found for PFJS ( P < 0.001) and PTF ( P < 0.001) impulse per km, suggesting that step frequency alteration was more effective at low running speed.

CONCLUSIONS

The effectiveness of step frequency alteration on PFJS and PTF impulse per km is dependent on the running speed. With regard to peak PFJS and PTF, step frequency alteration is equally effective at low and high running speeds. Step frequency alteration was not effective for peak rate of PFJS and PTF development. These findings can assist the optimization of patellofemoral joint and patellar tendon load management strategies.

Role of gluteus maximus and medius activation in the lower limb biomechanical control during functional single-leg Tasks: A systematic review

OBJECTIVES

Single-leg (SL) tasks are included as assessment and intervention strategies in several dysfunctions due to the inherent motor control requirement. The recruitment of gluteus maximus (GMAX) and medius (GMED) muscles is essential for proper biomechanical control of the knee and hip joints. The study aims to identify the role of gluteal activation in the biomechanical control of the lower limb during SL tasks.

METHODS

This is a systematic review with searches performed in Pubmed, CINAHL, MEDLINE, Web of Science, and Sportdiscus databases. Cross-sectional studies carried out with asymptomatic individuals were selected, containing hip and knee kinematic and kinetic outcomes assessed through 3D or 2D movement analysis and EMG activity of GMED and GMAX muscles. Two independent reviewers performed the procedures to select the studies, determine the methodological quality and extract the data.

RESULTS

The initial search resulted in 391 studies, and after the assessment procedures, 11 studies were included. Lower GMAX activation was associated with greater hip internal rotation (HIR) excursion and greater HIR moment, and lower GMED activation was associated with greater hip adduction (HAD)/knee abduction (KAB) excursions and greater KAB moment during single-leg squat (SLS).

CONCLUSIONS

The SL tasks showed a relevant association between the gluteal EMG and other biomechanical outcomes, mainly the SLS task. Interpretation must be cautious, as most studies present high and moderate methodological quality, especially on kinetic data.

Association of patellofemoral pain syndrome (PFPS) with quadratus lumborum and lower limb muscle tightness a cross-sectional study

Background

Patellofemoral pain syndrome (PFPS) is characterized by peripatellar or retro patellar pain, as a result of changes in the physical and biochemical components of the patellofemoral joint. The main contributory factor is being the excessive load on the patellofemoral joint. The change in the flexibility of lower limb muscles is one of the factors for developing PFPS.

Objective

To find the association of quadratus lumborum (QL) and lower limb muscles tightness in patients with unilateral PFPS.

Materials and methods

50 PFPS participants (21 male and 29 female) were included and assessed for muscle tightness on both affected and unaffected side. The QL, rectus femoris, hamstring, iliotibial band (ITB) and gastrocnemius tightness were measured using inch tape and mobile inclinometer. A Chi Square test and phi crammer's v criteria were used to check the association and the strength of it.

Results

A significant association was found between tightness of rectus femoris (PFPS-right Chi 19.99 p < 0.001; Phi-0.632, PFPS-left Chi-5.52 p = 0.019 and Phi- 0.332), gastrocnemius (PFPS-right Chi 8.78 p = 0.003; Phi-0.419, PFPS-left Chi- 11.41 p = 0.001; Phi- 0.478), iliotibial band (PFPS-right Chi 7.83 p = 0.005; Phi-0.396, PFPS left Chi-3.68 p = 0.055; Phi- 0.27). There was no significant association of hamstring tightness (PFPS-right Chi - 3.68 p = 0.055; Phi-0.055, PFPS left Chi-1.11 p = 0.291; Phi- 0.019) and QL (PFPS right Chi - 1.10 p = 0.293; Phi-0.293, PFPS left Chi-0.79 p = 0.372; Phi- 0.372).

Conclusion

PFPS was associated with tightness of rectus femoris, gastrocnemius, ITB and no association found between hamstring and QL muscle tightness and PFPS.

Relationship between impulse and kinetic variables during jumping and landing in volleyball players

BACKGROUND

This study examined the relationships between impulse and kinetic variables during jumping and landing in elite young male volleyball players.

METHODOLOGY

Eighteen players were recruited and asked to jump on a force plate, which allowed for the direct extraction of jump and landing kinetic data. The data was then analysed using stepwise regression to explore the relationship between landing impulse and various kinetic variables.

RESULTS

Our findings revealed a significant positive relationship between the peak rate of force development concentric (PRFD _CON) and impulse at landing (β = 0.537, p = 0.02). In a secondary analysis, we found that PRFD _CON (β = 0.497, p = 0.01) and time to peak power concentric (TPPC) (β = 0.424, p = 0.04) were also positively correlated with landing impulse. Importantly, PRFD _CON and TPPC were the variables that had the most muscular predictive power for impulse at landing.

CONCLUSION

These findings offer crucial insights into the biomechanics of jumping and landing in elite young male volleyball players, informing the development of more effective training programs. Our study identifies PRFD _CON and TPPC as critical factors for improving landing impulse, emphasizing the need to consider multiple kinetic variables when designing training programs for explosive skills. These insights can help optimize performance and reduce the risk of injury in elite young male volleyball players.

The effects of the Posterior X Taping versus augmented feedback on lower-extremity kinematic and muscle activity pattern during unilateral weight-bearing activities in men with tibiofemoral varus malalignment

PURPOSE

Tibiofemoral Varus Malalignment (TFRV) contributes to overuse injuries by altering lower limb biomechanics. Both Posterior X Taping (PXT) and Real Time Feedback (RTF), have each been recommended for subjects with TFRV as they are thought to enhance control of excessive tibiofemoral rotations. This paper evaluates this claim.

METHODS

A total of recreational male 24 athletes with TFRV participated in the current study. Kinematic and electromyography variables of lower extremity were synchronously ​recorded on five consecutive repetitions of the single-legged-squat (SLS) and forward-step-down) FSD) tasks before and after applications of PXT and RTF.

RESULTS

The subjects at post-intervention in RTF group exhibited decreased hip adduction during FSD, and decreased hip adduction and internal rotation during eccentric and concentric phases of the SLS; Additionally, we observed increased gluteus medius activity during eccentric phase of the SLS and FSD tasks. In contrast, subjects at the post-intervention in PXT group exhibited decreased tibiofemoral external rotation and increased ankle external rotation during all the phases of both SLS and FSD tasks.

CONCLUSION

These results suggest that the PXT and RTF interventions are recommended to immediately improve the functional defects of the subjects with TFRV during SLS and FSD tasks.

Are alterations in running biomechanics associated with running injuries? A systematic review with meta-analysis

BACKGROUND

No systematic review has investigated the main biomechanical variables as predictors of running-related injuries.

OBJECTIVE

To investigate the main biomechanical variables associated with running-related injuries.

METHODS

Medline via PubMed, EMBASE, SPORTDiscus, Web of Science, and CINAHL were searched from inception until 1 November 2021. Each study included must have investigated the association of at least one biomechanical variable (kinetics, kinematics, electromyography, or pressure distribution) with running injuries. The meta-analysis was conducted, and a modified version of the Downs and Black Quality Index was used for methodological quality evaluation.

RESULTS

Across the 82 studies included, 5465 runners were investigated. The meta-analysis was conducted with 11 biomechanical variables from 51 articles (n=2395). The peak hip adduction angle was the sole biomechanical variable associated with running injury and was found to be higher in injured runners (0.57, 95% CI 0.21, 0.94) compared to uninjured runners. However, this result was highly influenced by two studies (out of five studies) conducted by the same group of authors.

CONCLUSION

Clinicians, coaches, and runners should be aware that minimal evidence supports that alterations of running biomechanics are associated with running-related injuries. Heterogeneity in evaluation conditions and inconsistency in the naming and definitions of biomechanical variables make definitive conclusions challenging.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO, CRD42017068839.

Hip Strength Recovery After Anterior Cruciate Ligament Reconstruction

Background

Return-to-play (RTP) assessment after anterior cruciate ligament reconstruction (ACLR) rarely includes hip strength.

Hypothesis

It was hypothesized that (1) patients after ACLR will have weaker hip abduction (AB) and adduction (AD) strength compared with the contralateral limb, with larger deficits in women, (2) there will be a correlation between hip and thigh strength ratios and patient-reported outcomes (PROs), and (3) hip AB and AD strength will improve over time.

Study Design

Descriptive laboratory study.

Methods

Included were 140 patients (74 male, 66 female; mean age, 24.16 ± 10.82 years) who underwent RTP assessment at 6.1 ± 1.6 months after ACLR; 86 patients underwent a second assessment at 8.2 ± 2.2 months. Hip AB/AD and knee extension/flexion isometric strength were measured and normalized to body mass, and PRO scores were collected. Strength ratios (hip vs thigh), limb differences (injured vs uninjured), sex-based differences, and relationships between strength ratios and PROs were determined.

Results

Hip AB strength was weaker on the ACLR limb (ACLR vs contralateral: 1.85 ± 0.49 vs 1.89 ± 0.48 N·m/kg; P < .001) and hip AD torque was stronger (ACLR vs contralateral: 1.80 ± 0.51 vs 1.76 ± 0.52 N·m/kg; P = .004), with no sex-by-limb interaction found. Lower hip-to-thigh strength ratios of the ACLR limb were correlated with higher PRO scores (r = -0.17 to -0.25). Over time, hip AB strength increased in the ACLR limb more than in the contralateral limb (P = .01); however, the ACLR limb remained weaker in hip AB at visit 2 (ACLR vs contralateral: 1.88 ± 0.46 vs 1.91 ± 0.45 N·m/kg; P = .04). In both limbs, hip AD strength was greater at visit 2 than visit 1 (ACLR: 1.82 ± 0.48 vs 1.70 ± 0.48 N·m/kg; contralateral: 1.76 ± 0.47 vs 1.67 ± 0.47 N·m/kg; P < .01 for both).

Conclusion

The ACLR limb had weaker hip AB and stronger AD compared with the contralateral limb at initial assessment. Hip muscle strength recovery was not influenced by sex. Hip strength and symmetry improved over the course of rehabilitation. Although strength differences across limbs were minor, the clinical importance of these differences is still unknown.

Clinical Relevance

The evidence provided highlights the need to integrate hip strength into RTP assessments to identify hip strength deficits that may increase reinjury or lead to poor long-term outcomes.

Effects of pubertal growth variation on knee mechanics during walking in female and male adolescents

INTRODUCTION

Puberty substantially alters the body's mechanical properties, neuromuscular control, and sex differences therein, likely contributing to increased, sex-biased knee injury risk during adolescence. Female adolescents have higher risk for knee injuries than male adolescents of similar age engaging in similar physical activities, and much research has investigated sex differences in mechanical risk factors. However, few studies address the considerable variation in pubertal growth (timing, pace), knee mechanics, and injury susceptibility within sexes, or the impact of such growth variation on mechanical injury risk.

OBJECTIVES

The present study tested for effects of variation in pubertal growth on established mechanical knee injury risk factors, examining relationships between and within sexes.

METHODS

Pubertal growth indices describing variation in the timing and rate of pubertal growth were developed using principal component analysis and auxological data from serial stature measurements. Linear mixed models were applied to evaluate relationships between these indices and knee mechanics during walking in a sample of adolescents.

RESULTS

Later developing female adolescents with slower pubertal growth had higher extension moments throughout stance, whereas earlier developers had higher valgus knee angles and moments. In male adolescents, faster and later growth were related to higher extension moments throughout gait. In both sexes, faster growers had higher internal rotation moments at foot-strike.

CONCLUSIONS

Pubertal growth variation has important effects on mechanical knee injury risk in adolescence, affecting females and males differently. Earlier developing females exhibit greater injury risk via frontal plane factors, whereas later/faster developing males have elevated risk via sagittal plane mechanisms.

Relationship between kinesiophobia, isometric hip and knee torques to pelvic, hip and knee motion during the single-leg drop jump in women with patellofemoral pain: A cross-sectional study

BACKGROUND

Individuals with patellofemoral pain (PFP) have kinesiophobia and hip and knee strength deficits. These factors may be related to kinematic alterations of pelvic, hip and knee during a more demanding functional activity, such as jumping landing. The aim was to investigate the relationships between kinesiophobia and hip/knee torque to pelvic/hip/knee kinematics during the single-leg drop vertical jump in women with PFP.

METHOD

Thirty women with PFP were assessed with Tampa Scale for Kinesiophobia; isokinetic dynamometry of the hip extensor, hip abductor, and knee extensor; and three-dimensional motion analysis system during the single-leg drop vertical jump. A Pearson correlation matrix was used to investigate relationship among variables.

RESULTS

Fair correlations were found between increased kinesiophobia and increased peak hip internal rotation angle (r = 0.43; p = 0.018) as well as between greater peak knee extensor torque and greater peak knee flexion (r = 0.41; p = 0.022). Moderate to good correlation was found between increased peak hip abductor torque and increased peak contralateral pelvic drop (r = 0.52; p = 0.003). No other significant correlations were found between variables.

CONCLUSIONS

Kinesiophobia is associated with hip kinematics, but not with knee kinematics, during the single-leg vertical drop jump in women with PFP. The greater hip abductor torque is associated with greater contralateral pelvic drop. The positive relationship between knee extensor torque and knee flexion indicates that rehabilitation programs involving quadriceps muscle strengthening may assist women with PFP in control knee flexion and improve load absorption during jumping landing.

Does Increased Femoral Anteversion Can Cause Hip Abductor Muscle Weakness?

BACKGROUND

Increased femoral anteversion (IFA) causes functional problems (i.e., tripping, frequently falling, and fatigue) by affecting the pelvis and lower extremity biomechanics. In the frontal plane, increased contralateral pelvic drop and ipsilateral hip adduction, which are mainly considered deteriorated hip abductor muscle mechanisms, are associated with hip and knee injuries.

AIMS

The aim of this study was to examine the effects of femoral anteversion on hip abductor weakness and frontal plane pelvis-hip biomechanics during walking.

METHODS

The study included nine subjects with increased femoral anteversion and a control group of eleven subjects. Maximum isometric voluntary contraction (MIVC) values of the hip abductor muscles were measured with a handheld dynamometer. Three-dimensional gait analysis was performed for kinetic, kinematic, and temporo-spatial gait parameters. Non-parametric tests were used for statistical analysis (p < 0.05).

RESULTS

There was no significant difference found between the MIVC values of the IFA and control groups (p = 0.14). Moreover, no significant difference was determined between the ipsilateral peak hip adduction (p = 0.088) and contralateral pelvic drop (p = 0.149) in the stance phase. Additionally, there was no correlation between the peak hip adduction angle in the stance phase and normalized MIVC values in the IFA group (r = -0.198, p = 0.44), or in the control group (r = -0.174, p = 0.55). The deviations of pelvic rotation (p = 0.022), hip internal rotation (p = 0.003), and internal foot progression (p = 0.022), were found to be higher in the IFA group than in the controls.

CONCLUSIONS

IFA may not be associated with hip abductor muscle weakness, and it may not lead to the hip adduction and pelvic depression that can be seen in hip abductor weakness. Increased pelvic rotation and internal hip rotation during walking might be considered as a compensation for the femoral head-acetabulum alignment mechanism in the frontal plane.

Effects of Gluteus Maximus Muscle Activity and Pelvic Width on Dynamic Frontal Plane Hip Joint Stiffness During Gait in Healthy Young Women

CONTEXT

Excessive hip adduction and internal rotation are abnormal movements that may lead to the onset and progression of patellofemoral pain. Previous studies have reported that lower dynamic frontal plane hip joint stiffness in the gait of women is associated with the magnitude of hip adduction and internal rotation angles. However, the factors contributing to the lack of dynamic frontal plane hip joint stiffness in the gait of young women are unclear. This study aims to investigate the factors affecting dynamic frontal plane hip joint stiffness during the weight-acceptance phase of the gait of healthy young women.

DESIGN

Cross-sectional study.

METHODS

This study included 30 healthy women between the ages of 18 and 30 years. The pelvic width/femur length ratio was calculated by dividing the pelvic width by the femur length. Data on hip kinematics and kinetics and activation of the gluteus maximus and medius, tensor fasciae latae, and adductor longus muscles during gait were collected using a motion capture system, force plates, and surface electromyography. Stepwise multiple regression analysis was conducted to determine the extent to which each independent factor affected dynamic frontal plane hip joint stiffness.

RESULTS

In healthy young women, decreased dynamic frontal plane hip joint stiffness was associated with decreased muscle activity of the gluteus maximus during the gait, as well as greater pelvic width/femur length ratio.

CONCLUSIONS

Women with a relatively great pelvic width relative to femur length may have more difficulty in producing dynamic frontal plane hip joint stiffness. However, increasing the muscle activity of the gluteus maximus may contribute to increased dynamic frontal plane hip joint stiffness.

The Relationship between Lower Extremity Functional Performance and Balance after Anterior Cruciate Ligament Reconstruction: Results of Patients Treated with the Modified All-Inside Technique

BACKGROUND AND OBJECTIVES

Anterior cruciate ligament (ACL) ruptures are common injuries, and ACL reconstruction (ACLR) is among the most common surgical procedures in sports surgery. Our research aims to compare the 6-month post-operative results of the modified all-inside (MAI) ACLR technique, single leg hop tests (SLHT), and Y balance tests applied in different directions on the operated and non-operated sides.

MATERIALS AND METHODS

A retrospective cohort of 22 male recreational athletes who underwent MAI ACLR techniques performed by the same surgeon were evaluated. The functional knee strengths of the participants on the operated and non-operated sides were evaluated with five different tests of SLHTs: single hop for distance (SH), triple hop for distance (TH), crossover triple hop for distance (CH), medial side triple hop for distance (MSTH), and medial rotation (90°) with hop for distance (MRH). Their dynamic balance was evaluated with the Y balance Test.

RESULTS

Compared to pre-operative levels, there was a significant improvement in the mean Lysholm, Tegner, and IKDC scores during the post-operative period (p < 0.05). There was a difference between SH, THD, CHD, MSTH, and MRH on the operated and non-operative sides (p < 0.05). There was no difference between Y balance scores on the operated and non-operative sides, and there were no differences between LSI scores resulting from SLHTs (p > 0.05). There were no significant relationships between YBT (composite scores) and SH, TH, CH, MSTH, and MRH distances in the healthy leg (p > 0.05), but a significant correlation with only CH in the ACL leg (p < 0.05).

CONCLUSIONS

Our research shows that sixth-month post-operative SLHT findings were lower on the ACL side compared to the healthy side in patients tested with the MAI ACLR technique. However, when these scores are evaluated in terms of balance, it can be seen that both sides reveal similar findings. The similarity of LSIs in SLHTs applied in different directions, and balance scores of ACL and healthy sides revealed that the MAI technique is also an ACLR technique that can be used in athletes from a functional point of view.

Relationship between the knee valgus moment and the hip abductor and adductor activity during single-leg landing

OBJECTIVES

To reveal the relationship between the knee valgus moment (KVM) and the hip abductor and adductor activity during single-leg landing.

DESIGN

A cross-sectional study.

SETTING

Laboratory-based, between April 2020 and May 2021.

PARTICIPANTS

Thirty female collegiate athletes.

MAIN OUTCOME MEASURES

KVM, hip adduction angle, hip internal rotation angle, knee valgus angle (KVA), gluteus medius muscle activity, adductor longus muscle activity, adductor longus to gluteus medius activity ratio (ADD/GMED), and vertical component of the ground reaction force (vGRF).

RESULTS

Stepwise multiple regression analysis was performed. KVM was significantly positively associated with KVA (β = 0.613, p < 0.001), vGRF (β = 0.367, p = 0.010), and ADD/GMED (β = 0.289, p = 0.038).

CONCLUSIONS

Increased KVA, vGRF, and ADD/GMED were the independent factors that contributed to increased KVM during single-leg landing, and only ADD/GMED was found among the muscle activity values. The relative muscle activity of the gluteus medius and adductor longus, rather than those of the gluteus medius or adductor longus alone, may be useful in preventing anterior cruciate ligament injury during single-leg landing.

What is the Incidence of Subsequent Adjacent Joint Injury After Patellofemoral Pain?

OBJECTIVE

To investigate the incidence of subsequent lumbar spine, hip, and ankle-foot injuries after a diagnosis of patellofemoral pain.

DESIGN

Retrospective cohort study.

SETTING

Military Health System.

PARTICIPANTS

Individuals (n = 92,319) ages 17-60 diagnosed with patellofemoral pain between 2010-2011.

INTERVENTIONS

Therapeutic exercise.

MAIN OUTCOME MEASURES

Frequency of adjacent joint injuries in the 2-year period after initial patellofemoral pain injury, and hazard ratios (HR) with 95% confidence interval (CI) and Kaplan-Meier survival curves for risk of adjacent joint injury based on receiving therapeutic exercise for the initial injury.

RESULTS

After initial patellofemoral pain diagnosis, 42,983 (46.6%) individuals sought care for an adjacent joint injury. Of these, 19,587 (21.2%) were subsequently diagnosed with a lumbar injury, 2837 (3.1%) a hip injury, and 10,166 (11.0%) an ankle-foot injury. One in five (19.5%; n = 17,966) received therapeutic exercise which reduced the risk of having a subsequent lumbar (HR = 0.78, 95% CI 0.76-0.81), hip (HR = 0.93, 95% CI 0.87-0.98) or ankle-foot (HR = 0.86, 95% CI 0.83-0.90) injury.

CONCLUSION

The results suggest that a high number of individuals with patellofemoral pain will sustain an adjacent joint injury within 2 years although causal relationships cannot be determined. Receiving therapeutic exercise for the initial knee injury reduced the risk of sustaining an adjacent joint injury. This study helps provide normative data for subsequent injury rates in this population and guide development of future studies designed to understand causal factors.

Electromyographic analysis of the three subdivisions of gluteus medius during two different exercises: Wall press exercise and figure-of-four position

BACKGROUND

Gluteus medius (GM) is a segmented muscle involving three muscular subdivisions. Rehabilitation exercises has been suggested to strengthen specific subdivisions.

OBJECTIVE

This study aimed to evaluate muscular activation of the anterior, middle, and posterior subdivisions of the GM during two different exercises.

METHODS

A total of 28 healthy active subjects participated in this study. Muscle activity using surface electromyography was recorded for the three GM subdivisions during figure-of-four position (FFP) and wall press (WP). Non-parametric Kruskal-Wallis test was used to detect differences between GM subdivisions on each exercise and the Mann-Whitney U test was used to compare muscular activation across exercises.

RESULTS

There were statistically significant differences (P< 0.001) in all GM subdivision during FFP and WP exercises. Both exercises showed greater activation of the posterior subdivision than the middle and anterior subdivisions, with the WP causing highest activation of the posterior subdivision.

CONCLUSION

In line with the WP exercise, the FFP produces sufficient activity to provide potential strength gains on the posterior subdivision and could be a viable option to include in the early stages of the rehabilitation process. Clinicians may use this information to make more informed decisions about exercise selection for strengthening specific GM subdivision.

Focus of Attention During ACL Injury Prevention Exercises Affects Improvements in Jump-Landing Kinematics in Soccer Players: A Randomized Controlled Trial

ABSTRACT

Dalvandpour, N, Zareei, M, Abbasi, H, Abdoli, B, Mohammadian, MA, Rommers, N, and Rössler, R. Focus of attention during ACL injury prevention exercises affects improvements in jump-landing kinematics in soccer players: a randomized controlled trial. J Strength Cond Res 37(2): 337-342, 2023-Anterior cruciate ligament tears are severe and complex knee injuries that commonly occur in soccer. Prevent injuries enhance performance (PEP) is an exercise-based prevention program to effectively reduce anterior cruciate ligament injuries. It is, however, unclear how the delivery of the program contributes to its effectiveness. Therefore, we aimed to investigate the effect of the focus of attention that was emphasized during the delivery of the PEP program on jump-landing kinematics in male, elite-level, U21 soccer players. Forty-two players participated in this randomized controlled trial and were allocated to (a) the internal focus of attention (IF) group, receiving instructions focusing on the execution of the exercise (b), the external focus of attention (EF) group, receiving instructions focusing on the outcome of the exercise, or (c) the control group. Before and after the 8-week intervention, players performed a jump-landing task during which we measured hip and knee angles at the initial contact, peak knee flexion, and peak vertical ground reaction force using a 3-dimensional motion analyzer. A repeated-measures analysis of variance was used to compare groups over time. Significant time-by-group interaction effects with large effect sizes were found for hip flexion at all moments (p < 0.032; η2 > 0.15) and for the knee flexion angle at initial contact and maximum knee flexion (p < 0.001; η2 > 0.35), all in favor of the EF group. This shows that EF during PEP improves hip and knee joint kinematics in the sagittal plane more than IF. Therefore, EF during PEP instructions is preferred to increase the effectiveness of this injury prevention program.

The Running Readiness Scale as an Assessment of Kinematics Related to Knee Injury in Novice Female Runners

CONTEXT

Frontal- and transverse-plane kinematics have been prospectively identified as risk factors for running-related injuries in females. The Running Readiness Scale (RRS) may allow for clinical evaluation of these kinematics.

OBJECTIVES

To determine the reliability and validity of the RRS as an assessment of frontal- and transverse-plane running kinematics.

DESIGN

Cross-sectional study.

SETTING

University research laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 56 novice female runners (median [interquartile range] age = 34 years [26-47 years]).

MAIN OUTCOME MEASURE(S)

We collected 3-dimensional kinematics during running and RRS tasks: hopping, plank, step-ups, single-legged squats, and wall sit. Five clinicians assessed RRS performances 3 times each. Interrater and intrarater reliabilities of the total RRS score and individual tasks were calculated using the intraclass correlation coefficient and Fleiss κ, respectively. Pearson product moment correlation coefficients between peak joint angles measured during running and the same angles measured during RRS tasks were computed. Peak joint angles of high- and low-scoring participants were compared.

RESULTS

Interrater and intrarater reliabilities of assessment of the total RRS scores were good (intraclass correlation coefficients = 0.75 and 0.80, respectively). Reliability of assessing individual tasks was moderate to almost perfect (κ = 0.58-1.00). Peak hip adduction, contralateral pelvic drop, and knee abduction during running were correlated with the same angles measured during hopping, step-ups, and single-legged squats (r = 0.537-0.939). Peak knee internal rotation during running was correlated with peak knee internal rotation during step-ups (r = 0.831). Runners who scored high on the RRS demonstrated less knee abduction during running (P ≤ .01).

CONCLUSIONS

The RRS may effectively assess knee abduction in novice runners, but evaluation criteria or tasks may need to be modified to effectively characterize pelvic and transverse-plane knee kinematics.

Kinematic and Kinetic Gait Characteristics in People with Patellofemoral Pain: A Systematic Review and Meta-analysis

BACKGROUND

Patellofemoral pain (PFP) is a prevalent knee condition with many proposed biomechanically orientated etiological factors and treatments.

OBJECTIVE

We aimed to systematically review and synthesize the evidence for biomechanical variables (spatiotemporal, kinematic, kinetic) during walking and running in people with PFP compared with pain-free controls, and determine if biomechanical variables contribute to the development of PFP.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched Medline, CINAHL, SPORTDiscus, Embase, and Web of Science from inception to October 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

All study designs (prospective, case-control [± interventional component, provided pre-intervention data were reported for both groups], cross-sectional) comparing spatiotemporal, kinematic, and/or kinetic variables during walking and/or running between people with and without PFP.

RESULTS

We identified 55 studies involving 1300 people with PFP and 1393 pain-free controls. Overall pooled analysis identified that people with PFP had slower gait velocity [moderate evidence, standardized mean difference (SMD) - 0.50, 95% confidence interval (CI) - 0.72, - 0.27], lower cadence (limited evidence, SMD - 0.43, 95% CI - 0.74, - 0.12), and shorter stride length (limited evidence, SMD - 0.46, 95% CI - 0.80, - 0.12). People with PFP also had greater peak contralateral pelvic drop (moderate evidence, SMD - 0.46, 95% CI - 0.90, - 0.03), smaller peak knee flexion angles (moderate evidence, SMD - 0.30, 95% CI - 0.52, - 0.08), and smaller peak knee extension moments (limited evidence, SMD - 0.41, 95% CI - 0.75, - 0.07) compared with controls. Females with PFP had greater peak hip flexion (moderate evidence, SMD 0.83, 95% CI 0.30, 1.36) and rearfoot eversion (limited evidence, SMD 0.59, 95% CI 0.03, 1.14) angles compared to pain-free females. No significant between-group differences were identified for all other biomechanical variables. Data pooling was not possible for prospective studies.

CONCLUSION

A limited number of biomechanical differences exist when comparing people with and without PFP, mostly characterized by small-to-moderate effect sizes. People with PFP ambulate slower, with lower cadence and a shortened stride length, greater contralateral pelvic drop, and lower knee flexion angles and knee extension moments. It is unclear whether these features are present prior to PFP onset or occur as pain-compensatory movement strategies given the lack of prospective data.

TRIAL REGISTRATION

PROSPERO # CRD42019080241.

The Effect of Fatigue on Trunk and Pelvic Jump-Landing Biomechanics in View of Lower Extremity Loading: A Systematic Review

Fatigue has often been considered a risk factor for developing sports injuries, modulating lower extremity jump-landing biomechanics. The impact of fatigue on proximal trunk and pelvic biomechanics has been suggested to play an important role in lower extremity loading and injury risk, yet the available evidence remains ambiguous as the trunk and pelvis were often not the primary focus of research. Therefore, the purpose of this systematic review was to determine how fatigue affects trunk and pelvic three-dimensional jump-landing biomechanics. PubMed (MEDLINE), Web of Science, Embase, CINAHL and SPORTDiscus were consulted up to and including April 2022 for potential studies investigating the effect of fatigue on trunk and pelvic kinematics, kinetics and/or muscular activity during jump-landing tasks in healthy, physically active populations. Methodological quality of the studies was assessed by the modified Downs and Black checklist. Twenty-one studies were included and methodological quality was moderate to high among these studies. The results indicate prevailing evidence for more trunk flexion during standardized jump-landing tasks after lower extremity muscle fatigue. Otherwise, lumbo-pelvic-hip muscle fatigue does not seem to elicit major detrimental changes to these jump-landing biomechanics. Although a wide variability of trunk and pelvic jump-landing strategies was observed, the results provide evidence for increased trunk flexion after lower extremity muscle fatigue. This proximal strategy is suggested to help unload fatigued lower extremity structures and lack of this compensation might increase knee injury risk.