scholarly journals Neuromuscular Changes After Aerobic Exercise in People with Anterior Cruciate Ligament– Reconstructed Knees

2011 ◽  
Vol 46 (5) ◽  
pp. 476-483 ◽  
Author(s):  
Elizabeth C. Dalton ◽  
Kate R. Pfile ◽  
Gerald R. Weniger ◽  
Christopher D. Ingersoll ◽  
Daniel Herman ◽  
...  
Keyword(s):  
Aerobic Exercise ◽  
Muscle Activation ◽  
Dynamic Balance ◽  
Cruciate Ligament ◽  
Vertical Jump ◽  
Gluteus Medius ◽  
Gluteus Medius Muscle ◽  
Vertical Jump Height ◽  
Hip Abduction ◽  
Anterior Cruciate

Context: Anterior cruciate ligament (ACL) reconstructions are common, especially in young, active people. The lower extremity neuromuscular adaptations seen after aerobic exercise provide information about how previously injured patients perform and highlight deficits and, hence, areas for focused treatment. Little information is available about neuromuscular performance after aerobic exercise in people with ACL reconstructions. Objective: To compare dynamic balance, gluteus medius muscle activation, vertical jump height, and hip muscle strength after aerobic exercise in people with ACL-reconstructed knees. Design: Case-control study. Setting: Research laboratory. Patients or Other Participants: Of 34 recreationally active volunteers, 17 had a unilateral primary ACL reconstruction at least 2 years earlier and 17 were matched controls. Intervention(s): All participants performed 20 minutes of aerobic exercise on a treadmill. Main Outcome Measure(s): We recorded dynamic, single-legged balance electromyographic gluteus medius muscle activation, single-legged vertical jump height, and maximum isometric strength for hip abduction, extension, and external rotation preexercise and postexercise. Results: Participants with ACL reconstructions exhibited shorter reach distances during dynamic balance tasks, indicating poorer dynamic balance, and less gluteus medius muscle electromyographic activation. Reductions in hip abduction and extension strength after exercise were noted in all participants; however, those with ACL reconstructions displayed greater hip extensor strength loss after aerobic exercise than did the control group. Conclusions: Neuromuscular changes after aerobic exercise exist in both patients with ACL reconstructions and controls. The former group may experience greater deficits in hip extensor strength after aerobic exercise. Reduced reach distances in people with ACL reconstructions may represent a protective mechanism against excessive tibiofemoral rotation during dynamic balance. Clinicians should identify weaknesses in the resting state and after aerobic exercise in recreationally active patients and those with ACL reconstructions.

scholarly journals Quadriceps Function After Exercise in Patients with Anterior Cruciate Ligament–Reconstructed Knees Wearing Knee Braces

2011 ◽  
Vol 46 (6) ◽  
pp. 615-620 ◽  
Author(s):  
Alexis G. Davis ◽  
Brian G. Pietrosimone ◽  
Christopher D. Ingersoll ◽  
Kelli Pugh ◽  
Joseph M. Hart
Keyword(s):  
Anterior Cruciate Ligament ◽  
Aerobic Exercise ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Knee Brace ◽  
Maximal Voluntary Isometric Contraction ◽  
Before And After ◽  
Knee Braces ◽  
Anterior Cruciate ◽  
Quadriceps Function

Context: Knee braces and neoprene sleeves are commonly worn by people with anterior cruciate ligament reconstructions (ACLRs) during athletic activity. How knee braces and sleeves affect muscle activation in people with ACLRs is unclear.Purpose: To determine the effects of knee braces and neoprene knee sleeves on the quadriceps central activation ratio (CAR) before and after aerobic exercise in people with ACLRs.Design: Crossover study.Patients or Other Participants: Fourteen people with a history of ACLR (9 women, 5 men: age = 23.61 ± 4.44 years, height = 174.09 ± 9.82 cm, mass = 75.35 ± 17.48 kg, months since ACLR = 40.62 ± 20.41).Intervention(s): During each of 3 sessions, participants performed a standardized aerobic exercise protocol on a treadmill. The independent variables were condition (brace, sleeve, or control) and time (baseline, pre-exercise with brace, postexercise with brace, postexercise without brace).Main Outcome Measure(s): Normalized torque measured during a maximal voluntary isometric contraction (TMVIC) and CAR were measured by a blinded assessor using the superimposed burst technique. The CAR was expressed as a percentage of full muscle activation. The quadriceps CAR and TMVIC were measured 4 times during each session: baseline, pre-exercise with brace, postexercise with brace, and postexercise without brace.Results: Immediately after the application of the knee brace, TMVIC decreased (P = .01), but no differences between bracing conditions were observed. We noted reduced TMVIC and CAR (P < .001) after exercise, both with and without the brace. No differences were seen between bracing conditions after aerobic exercise.Conclusions: The decrease in TMVIC immediately after brace application was not accompanied by differences between bracing conditions. Wearing a knee brace or neoprene sleeve did not seem to affect the deterioration of quadriceps function after aerobic exercise.

scholarly journals Volitional Spine Stabilization During a Drop Vertical Jump From Different Landing Heights: Implications for Anterior Cruciate Ligament Injury

2016 ◽  
Vol 51 (12) ◽  
pp. 1003-1012 ◽  
Author(s):  
Ram Haddas ◽  
Troy Hooper ◽  
C. Roger James ◽  
Phillip S. Sizer
Keyword(s):  
Anterior Cruciate Ligament ◽  
Lower Extremity ◽  
Injury Risk ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Vertical Jump ◽  
Ligament Injury ◽  
Lower Extremity Muscle ◽  
Anterior Cruciate ◽  
Drop Vertical Jump

Context:Volitional preemptive abdominal contraction (VPAC) during dynamic activities may alter trunk motion, but the role of the core musculature in positioning the trunk during landing tasks is unclear.Objective:To determine whether volitional core-muscle activation incorporated during a drop vertical jump alters lower extremity kinematics and kinetics, as well as trunk and lower extremity muscle activity at different landing heights.Design:Controlled laboratory study.Setting:Clinical biomechanics laboratory.Patients or Other Participants:Thirty-two young healthy adults, consisting of 17 men (age = 25.24 ± 2.88 years, height = 1.85 ± 0.06 m, mass = 89.68 ± 16.80 kg) and 15 women (age = 23.93 ± 1.33 years, height = 1.67 ± 0.08 m, mass = 89.68 ± 5.28 kg).Intervention(s):Core-muscle activation using VPAC.Main Outcome Measure(s):We collected 3-dimensional ankle, knee, and hip motions, moments, and powers; ground reaction forces; and trunk and lower extremity muscle activity during 0.30- and 0.50-m drop vertical-jump landings.Results:During landing from a 0.30-m height, VPAC performance increased external oblique and semitendinosis activity, knee flexion, and knee internal rotation and decreased knee-abduction moment and knee-energy absorption. During the 0.50-m landing, the VPAC increased external oblique and semitendinosis activity, knee flexion, and hip flexion and decreased ankle inversion and hip-energy absorption.Conclusions:The VPAC performance during landing may protect the anterior cruciate ligament during different landing phases from different heights, creating a protective advantage just before ground contact and after the impact phase. Incorporating VPAC during high injury-risk activities may enhance pelvic stability, improve lower extremity positioning and sensorimotor control, and reduce anterior cruciate ligament injury risk while protecting the lumbar spine.

scholarly journals The Indirect Role of Gluteus Medius Muscle in Knee Joint Stability during Unilateral Vertical Jump and Landing on Unstable Surface in Young Trained Males

2021 ◽  
Vol 11 (16) ◽  
pp. 7421
Author(s):  
Balázs Sebesi ◽  
Ádám Fésüs ◽  
Mátyás Varga ◽  
Tamás Atlasz ◽  
Kitty Vadász ◽  
...  
Keyword(s):  
Knee Joint ◽  
Vastus Lateralis ◽  
Cruciate Ligament ◽  
Vertical Jump ◽  
Gluteus Medius ◽  
Biceps Femoris ◽  
Jump Performance ◽  
Unstable Surface ◽  
Flexion Extension ◽  
Hip Abduction

(1) In the present investigation, we tested the hypothesis that unilateral countermovement jump performance is associated with knee joint stabilization ability during unilateral landing on unstable surface. (2) Twenty-five male sport students were tested for dynamometric knee extension and flexion, and hip abduction isometric strength. Myolectric activity of vastus lateralis and medialis, gluteus medius, and biceps femoris muscles were measured during unilateral countermovement vertical jump performed on a force plate, and during unilateral landing on unstable surface. (3) Vertical jump impulse negatively correlated with biceps femoris activation at landing. Participants with greater hip abduction force performed greater vertical jump impulse, and activated the biceps femoris less when landing on unstable surface. Furthermore, participants with smaller knee flexion/extension torque ratio increased biceps femoris/vastus medialis activation ratio at landing. (4) We conclude that hip abduction strength is an important contributor to unilateral vertical jump performance. Because biceps femoris is considered the synergist of the anterior cruciate ligament, we also propose that hip abductors are primary frontal plane protectors of the knee joint by reducing knee valgus and stress, allowing for smaller biceps femoris co-activation (secondary protection) at landing on unstable surface.

scholarly journals Energy Absorption Contribution and Strength in Female Athletes at Return to Sport After Anterior Cruciate Ligament Reconstruction: Comparison With Healthy Controls

2018 ◽  
Vol 6 (3) ◽  
pp. 232596711875952 ◽  
Author(s):  
Marie E. Boo ◽  
J. Craig Garrison ◽  
Joseph P. Hannon ◽  
Kalyssa M. Creed ◽  
Shiho Goto ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Energy Absorption ◽  
Cruciate Ligament ◽  
Vertical Jump ◽  
Return To Sport ◽  
Quadriceps Strength ◽  
Activity Level ◽  
Group Differences ◽  
Hip Abduction ◽  
Anterior Cruciate

Background: Female patients are more likely to suffer a second anterior cruciate ligament (ACL) injury after ACL reconstruction (ACLR) and return to sport (RTS) compared with healthy female controls. Few studies have examined the energy absorption contribution (EAC) that could lead to this subsequent injury. Hypothesis: The ACLR group would demonstrate an altered EAC between joints (hip, knee, and ankle) but no difference in quadriceps, hip abduction, or hip external rotation (ER) strength at the time of RTS. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 34 female participants (ACLR: n = 17; control: n = 17) were enrolled in the study and matched for age and activity level. Jump landing performance for the initial 50 milliseconds of landing of a lateral-vertical jump was assessed using a 10-camera 3-dimensional motion capture system and 2 force plates. Isokinetic quadriceps strength was measured using a Biodex machine, and hip abduction and ER isometric strength were measured using a handheld dynamometer. All values were normalized to the participant’s height and weight. A 1-way multivariate analysis of variance was used to assess between-group differences in the EAC at the hip, knee, and ankle. Two 1-way analyses of variance were used to independently examine quadriceps, hip abduction, and hip ER strength between the groups. Results: Significant differences in the EAC were found between the groups for the involved hip ( P = .002), uninvolved hip ( P = .005), and involved ankle ( P = .023). There were no between-group differences in the EAC for the involved or uninvolved knee or the uninvolved ankle. Patients who underwent ACLR demonstrated significantly decreased quadriceps strength on the involved limb ( P = .02) and decreased hip ER strength on both the involved ( P = .005) and uninvolved limbs ( P = .002). No significant strength differences were found between the groups for the uninvolved quadriceps or for involved or uninvolved hip abduction. Conclusion: At RTS, patients who underwent ACLR utilized a greater hip EAC bilaterally and a decreased involved ankle EAC during a lateral-vertical jump. Furthermore, quadriceps strength on the involved limb and hip ER strength of bilateral lower extremities remained decreased. This could place greater stress on the ACL graft and ultimately lead to an increased injury risk.

scholarly journals Hip-Abductor Fatigue and Single-Leg Landing Mechanics in Women Athletes

2011 ◽  
Vol 46 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Mary F. Patrek ◽  
Thomas W. Kernozek ◽  
John D. Willson ◽  
Glenn A. Wright ◽  
Scott T. Doberstein
Keyword(s):  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Frontal Plane ◽  
Gluteus Medius ◽  
Initial Contact ◽  
Fatigue Protocol ◽  
Landing Mechanics ◽  
Hip Abduction ◽  
Hip Abductor ◽  
Anterior Cruciate

Abstract Context: Reduced hip-abductor strength and muscle activation may be associated with altered lower extremity mechanics, which are thought to increase the risk for anterior cruciate ligament injury. However, experimental evidence supporting this relationship is limited. Objective: To examine the changes in single-leg landing mechanics and gluteus medius recruitment that occur after a hip-abductor fatigue protocol. Design: Descriptive laboratory study. Patients or Other Participants: Twenty physically active women (age  =  21.0 ± 1.3 years). Intervention(s): Participants were tested before (prefatigue) and after (postfatigue) a hip-abductor fatigue protocol consisting of repetitive side-lying hip abduction. Main Outcome Measure(s): Outcome measures included sagittal-plane and frontal-plane hip and knee kinematics at initial contact and at 60 milliseconds after initial contact during 5 single-leg landings from a height of 40 cm. Peak hip and knee sagittal-plane and frontal-plane joint moments during this time interval were also analyzed. Measures of gluteus medius activation, including latency, peak amplitude, and integrated signal, were recorded. Results: A small (<1°) increase in hip-abduction angle at initial contact and a small (<1°) decrease in knee-abduction (valgus) angle at 60 milliseconds after contact were observed in the postfatigue landing condition. No other kinematic changes were noted for the knee or hip at initial contact or at 60 milliseconds after initial contact. Peak external knee-adduction moment decreased 27% and peak hip adduction moment decreased 24% during the postfatigue landing condition. Gluteus medius activation was delayed after the protocol, but no difference in peak or integrated signal was seen during the landing trials. Conclusions: Changes observed during single-leg landings after hip-abductor fatigue were not generally considered unfavorable to the integrity of the anterior cruciate ligament. Further work may be justified to study the role of hip-abductor activation in protecting the knee during landing.

Effect of side-sling plank exercise on trunk and hip muscle activation in subjects with gluteus medius weakness

2021 ◽  
pp. 1-9
Author(s):  
Seung-Min Baik ◽  
Heon-Seock Cynn ◽  
Chung-Hwi Yi ◽  
Ji-Hyun Lee ◽  
Jung-Hoon Choi ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Erector Spinae ◽  
Lumbar Multifidus ◽  
Hip Muscle ◽  
Hip Abduction ◽  
Medial Rotation ◽  
Hip Muscles ◽  
Tensor Fasciae Latae

BACKGROUND: The effectiveness of side-sling plank (SSP) exercises on trunk and hip muscle activation in subjects with gluteus medius (Gmed) weakness is unclear. OBJECTIVE: To quantify muscle activation of the rectus abdominis (RA), external oblique (EO), erector spinae (ES), lumbar multifidus (LM), Gmed, gluteus maximus (Gmax), and tensor fasciae latae (TFL) during SSP with three different hip rotations compared to side-lying hip abduction (SHA) exercise in subjects with Gmed weakness. METHODS: Twenty-two subjects with Gmed weakness were recruited. SHA and three types of SSP exercises were performed: SSP with neutral hip (SSP-N), hip lateral rotation (SSP-L), and hip medial rotation (SSP-M). Surface electromyography was used to measure the activation of the trunk and hip muscles. RESULTS: The trunk and hip muscles activations were generally significantly higher level during three SSP than SHA. SSP-M showed significantly lower EO activation while significantly higher ES and LM activation than SSP-L. Gmed activation was significantly higher during SSP-M than during SSP-L. TFL activation was significantly lower during SSP-M than during SSP-N and SSP-L. CONCLUSIONS: SSP could be prescribed for patients who have reduced Gmed strength after injuries. Especially, SSP-M could be applied for patients who have Gmed weakness with dominant TFL.

Acceleration and Jerk After a Jump Stabilization Task in Individuals With and Without Chronic Ankle Instability

2021 ◽  
pp. 1-6
Author(s):  
Kyle B. Kosik ◽  
Kathryn Lucas ◽  
Matthew C. Hoch ◽  
Jacob T. Hartzell ◽  
Katherine A. Bain ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Ankle Instability ◽  
Dynamic Balance ◽  
Vertical Jump ◽  
Chronic Ankle Instability ◽  
Mean Difference ◽  
Vertical Jump Height ◽  
Study Participants ◽  
Third Derivative ◽  
Control Study

Studies have demonstrated that individuals with chronic ankle instability (CAI) have diminished dynamic stability. Jerk-based measures have been utilized to examine dynamic balance because of their ability to quantify changes in acceleration and may provide an understanding of the postural corrections that occur during stabilizing following a jumping task. The purpose of this study was to compare acceleration and jerk following a jump stabilization task between individuals with CAI and the uninjured controls. Thirty-nine participants volunteered to participate in this case control study. Participants completed a jump stabilization task requiring them to jump off 2 feet, touch a marker set at 50% of their maximal vertical jump height, land on a single limb, and maintain balance for 3 seconds. Acceleration was calculated as the second derivative, and jerk was calculated as the third derivative of the displacement of the resultant vector position. Participants with CAI had greater acceleration (mean difference = 55.6 cm/s2; 95% confidence interval, 10.3 to 100.90; P = .017) and jerk compared with the uninjured controls (mean difference = 1804.5 cm/s3; 95% confidence interval, 98.7 to 3510.3; P = .039). These results suggest that individuals with CAI made faster and more frequent active postural control corrections to regain balance following a jump compared with the uninjured controls.

scholarly journals Conditioning Brain Responses to Improve Quadriceps Function in an Individual With Anterior Cruciate Ligament Reconstruction

2019 ◽  
Vol 11 (4) ◽  
pp. 306-315 ◽  
Author(s):  
Chandramouli Krishnan ◽  
Edward P. Washabaugh ◽  
Aviroop Dutt-Mazumder ◽  
Scott R. Brown ◽  
Edward M. Wojtys ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Operant Conditioning ◽  
Muscle Activation ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Corticospinal Excitability ◽  
Knee Extensor Strength ◽  
Anterior Cruciate ◽  
Quadriceps Function

Background: Persistent quadriceps weakness and activation failure are common in individuals with anterior cruciate ligament (ACL) reconstruction. A growing body of evidence indicates that this chronic quadriceps dysfunction could be partly mediated due to reduced corticospinal excitability. However, current rehabilitation approaches do not directly target corticospinal deficits, which may be critical for restoring optimal clinical outcomes after the surgery. This case study tested the feasibility of operant conditioning of torque responses evoked by transcranial magnetic stimulation (TMS) to improve quadriceps function after ACL reconstruction. Hypothesis: Operant conditioning of motor evoked torque responses would improve quadriceps strength, voluntary activation, and corticospinal excitability. Study Design: Case study and research report. Level of Evidence: Level 5. Methods: A 24-year-old male with an ACL reconstruction (6 months postsurgery) trained for 20 sessions (2-3 times per week for 8 weeks) to increase his TMS-induced motor evoked torque response (MEP torque) of the quadriceps muscles using operant conditioning principles. Knee extensor strength, voluntary quadriceps muscle activation, and quadriceps corticospinal excitability were evaluated at 3 time points: preintervention (pre), 4 weeks (mid), and immediately after the intervention (post). Results: The participant was able to successfully condition (ie, increase) the quadriceps MEP torque after 1 training session, and the conditioned MEP torque gradually increased over the course of 20 training sessions to reach about 500% of the initial value at the end of training. The participant’s control MEP torque values and corticospinal excitability, which were measured outside of the conditioning paradigm, also increased with training. These changes were paralleled by improvements in knee extensor strength and voluntary quadriceps muscle activation. Conclusion: This study shows that operant conditioning of MEP torque is a feasible approach to improving quadriceps corticospinal excitability and quadriceps function after ACL reconstruction and encourages further testing in a larger cohort of ACL-reconstructed individuals. Clinical Relevance: Operant conditioning may serve as a potential therapeutic adjuvant for ACL rehabilitation.

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