Relationship between lower limb EMG activity and knee frontal plane projection angle during a single-legged drop jump

ObjectivesTo assess a relationship between lower limb muscle activity and the frontal plane knee kinematics during a single-legged drop jump.DesignCorrelation study;SettingFunctional Anatomy Laboratory.Participants35 healthy collegiate male athletes.Main outcome measuresMuscle activity (%MVIC) of gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius and lateral gastrocnemius; peak knee frontal plane projection angle; and Pearson's correlation coefficients between muscle activity and peak knee frontal plane projection angle. All outcomes were assessed for both dominant and non-dominant limbs.ResultsSignificant correlations (r = 0.46–0.60, P < 0.05) were found between the muscle activities of the gluteus maximus, gluteus medius, biceps femoris, and semitendinosus, when compared to the knee frontal plane projection angle.ConclusionGluteal muscles and hamstring muscles are associated with the peak knee frontal plane projection angle during a single-legged drop jump test. Thus, gluteal and hamstring muscle activities should be considered when developing rehabilitation or injury prevention programs.     

Kinematic and electromyographic analysis in patients with patellofemoral pain syndrome during single leg triple hop test

Possible delays in pre-activation or deficiencies in the activity of the dynamic muscle stabilizers of the knee and hip joints are the most common causes of the patellofemoral pain syndrome (PFPS). The aim of the study was to compare kinematic variables and electromyographic activity of the vastus lateralis, biceps femoris, gluteus maximus and gluteus medius muscles between patients with PFPS and health subjects during the single leg triple hop test (SLTHT). This study included 14 female with PFPS (PFPS group) and 14 female healthy with no history of knee pain (Healthy group). Kinematic and EMG data ware collected through participants performed a single session of the SLTHT. The PFPS group exhibited a significant increase (p < 0.05) in the EMG activity of the biceps femoris and vastus lateralis muscles, when compared with the healthy group in pre-activity and during the stance phase. This same result was also found for the vastus lateralis muscle (p < 0.05) when analyzing the EMG activity during the eccentric phase of the stance phase. In kinematic analysis, no significant differences were found between the groups. These results indicate that biceps femoris and vastus lateralis muscles mainly during the pre-activation phase and stance phases of the SLTHT are more active in PFPS group among healthy group.     

Altered movement strategies during jump landing/cutting in patients with chronic ankle instability

Centrally mediated changes in sensorimotor function have been reported in patients with chronic ankle instability (CAI). However, little is known regarding supraspinal/spinal adaptations during lower‐extremity dynamic movement during a multiplanar, single‐leg landing/cutting task. The purpose of this study was to investigate the effect of CAI on landing/cutting neuromechanics, including lower‐extremity kinematic, electromyography (EMG) activation, and ground reaction force (GRF) characteristics. One hundred CAI patients and 100 matched healthy controls performed five trials of a jump landing/cutting task. Sagittal‐ and frontal‐plane ankle, knee and hip kinematics, EMG activation in eight lower‐extremity muscles, and 3D GRF were collected during jump landing/cutting. Functional analyses of variance (FANOVA) were used to evaluate between‐group differences for dependent variables throughout the entire ground contact of the task. Relative to the control group, the CAI group revealed (a) reduced dorsiflexion, increased knee and hip flexion angles, (b) increased inversion and hip adduction angles, (c) increased EMG activation of medial gastrocnemius, peroneus longus, adductor longus, vastus lateralis, gluteus medius, and gluteus maximus, and (d) increased posterior and vertical GRF during initial landing, and reduced medial, posterior, and vertical GRF during mid‐landing and mid‐cutting. CAI patients demonstrated alterations in landing/cutting movement strategies as demonstrated by a higher susceptibility of foot placement for lateral ankle sprains, and more flexed positions of the knee and hip with higher EMG activation of knee and hip extensors to modulate GRF to compensate for the unstable ankle. This apparent compensation may be due to mechanical (limited dorsiflexion angle) and/or sensorimotor deficits in the ankle.     

Gender differences in gluteus medius muscle activity exist in soccer players performing a forward jump

The purpose of this study was to evaluate gender differences in muscle activity while landing from a forward jump. Eight male and 8 female division-one varsity soccer athletes participated in this study. Subjects performed five trials of a 100 cm forward jump single leg landing. Surface electromyography (EMG) was collected at the gluteus medius, vastus lateralis, lateral hamstring, and medial gastrocnemius. Data were interpreted by VICON workstation and analyzed with Acknowledge software. Average root mean square of 200 ms following initial heel contact from landing were normalized to static one-leg stance and used in data analysis. A fixed-effect multivariate analysis of variance showed average gluteus medius activity was significantly higher in males (7.16 +/- 3.16) than in females (2.62 +/- 0.95). There were no differences between genders for any of the other muscles collected. Gender-specific neuromuscular strategies used to attenuate the forces of landing may involve more gluteus medius muscle activity in males than in females.     

Muscle contributions to tibiofemoral shear forces and valgus and rotational joint moments during single leg drop landing

Anterior cruciate ligament (ACL) injuries commonly occur during single-leg landing tasks and are a burdensome condition. Previous studies indicate that muscle forces play an important role in controlling ligamentous loading, yet these studies have typically used cadaveric models considering only the knee-spanning quadriceps, hamstrings, and gastrocnemius muscle groups. Any muscles (including non-knee-spanning muscles) capable of opposing the anterior shear joint reaction force and the valgus joint reaction moment are thought to have the greatest potential for protecting the ACL from injury. Thus, the purpose of this study was to investigate how lower-limb muscles modulate knee joint loading during a single-leg drop landing task. An electromyography-informed neuromusculoskeletal modeling approach was used to compute lower-limb muscle force contributions to the anterior shear joint reaction force and the valgus joint reaction moment at the knee during a single-leg drop landing task. The average shear joint reaction force ranged from 153 N of anterior shear force to 744 N of posterior shear force. The muscles that generated the greatest posterior shear force were the soleus, medial hamstrings, and biceps femoris, contributing up to 393 N, 359 N, and 162 N, respectively. The average frontal plane joint reaction moment ranged from a 19 Nm varus moment to a 6 Nm valgus moment. The valgus moment was primarily opposed by the gluteus medius, gluteus minimus, and soleus, with these muscles providing contributions of up to 38, 22, and 20 Nm toward a varus moment, respectively. The findings identify key muscles that mitigate loads on the ACL.     

Gluteus medius muscle activity during gait in people with and without chronic nonspecific low back pain: A case control study

BackgroundResearch investigating differences in gluteus medius muscle activity in those with and without chronic nonspecific low back pain is both limited and conflicting. Additionally, in these populations the relationship between gluteus medius muscle activity, foot type, and transversus abdominis muscle thickness is unclear.Research questionWe aimed to investigate gluteus medius muscle activity during gait in those with and without chronic nonspecific low back pain. Secondarily, we aimed to explore the association between gluteus medius muscle activity, foot type, and transversus abdominis muscle thickness within groups.MethodsThis case control study recruited 30 people with and 30 people without chronic nonspecific low back pain and matched participants by age (±5 years), sex, and body mass index (±2 BMI units). Gluteus medius muscle activity was measured with surface electromyography during walking gait, with foot type and transversus abdominis muscle thickness measured with the Foot Posture Index and ultrasound respectively. The Mann-Whitney U test was used to investigate differences in gluteus medius muscle activity between groups. Spearman rank order correlation was performed to explore the association between gluteus medius muscle activity, foot type, and transversus abdominis thickness within each group. A linear regression was used to analyse significant correlations (P < 0.05).ResultsWe found no significant differences in gluteus medius muscle activity between groups. However, there was a moderate correlation between the Foot Posture Index score and gluteus medius peak amplitude (P = 0.04) for those with mild to moderate chronic nonspecific low back pain.SignificanceClinicians should be aware that patients with mild to moderate chronic nonspecific low back pain may not demonstrate significant differences in gluteus medius muscle activity compared to those without back pain. Additionally, higher peak gluteus medius muscle activity is likely to occur in people with mild to moderate chronic nonspecific low back pain and planus feet.     

Effect of chronic ankle instability on lower extremity kinematics,dynamic postural stability,and muscle activity during unilateral jump-landing tasks: A systematic review and meta-analysis

ObjectiveTo determine if individuals with chronic ankle instability (CAI) demonstrate altered landing kinematics, muscle activity, and impaired dynamic postural stability during a unilateral jump-landing task.Methods21 studies were included from PubMed, MEDLINE, Embase and CINAHL searched on September 26, 2021. Mean differences in joint angles and muscle activity between CAI and controls were analysed as continuous variables and pooled using a random-effects model to obtain standardised mean differences and 95% confidence intervals. Dynamic postural stability measured using time to stabilisation (TTS) was assessed qualitatively.ResultsWe found greater plantarflexion (pooled SMD = 0.33, 95%CI [0.02,0.65]), reduced knee flexion (pooled SMD = −0.67, 95%CI [−0.97, −0.37]), and reduced hip flexion (pooled SMD = −0.52, 95%CI [−0.96, −0.07]) in CAI after landing. Regarding muscle activity, we observed reduced peroneus longus muscle activation (pooled SMD = −0.77, 95% CI [−1.17, −0.36]) in CAI prior to landing.ConclusionOur study provides preliminary evidence of altered landing kinematics in the sagittal plane and reduced peroneus muscle activity in CAI during a dynamic jump-landing task. These results may have clinical implications in the development of more effective and targeted rehabilitation programmes for patients with CAI.     

Muscle contributions to propulsion and braking during walking and running: Insight from external force perturbations

There remains substantial debate as to the specific contributions of individual muscles to center of mass accelerations during walking and running. To gain insight, we altered the demand for muscular propulsion and braking by applying external horizontal impeding and aiding forces near the center of mass as subjects walked and ran on a treadmill. We recorded electromyographic activity of the gluteus maximus (superior and inferior portions), the gluteus medius, biceps femoris, semitendinosus/membrinosus, vastus medialis, lateral and medial gastrocnemius and soleus. We reasoned that activity in a propulsive muscle would increase with external impeding force and decrease with external aiding force whereas activity in a braking muscle would show the opposite. We found that during walking the gastrocnemius and gluteus maximus provide propulsion while the vasti are central in providing braking. During running, we found that the gluteus maximus, vastus medialis, gastrocnemius and soleus all contribute to propulsion.     

Gluteus medius and minimus activity during stepping tasks: Comparisons between people with hip osteoarthritis and matched control participants

BackgroundAltered gluteus minimus (GMin) activity has been identified in people with hip osteoarthritis (OA) during gait with some evidence of altered gluteus medius (GMed) activity in patients with advanced OA. It is not known whether these muscles also exhibit altered activity during other functional tasks.Research questionDoes gluteal muscle activity during stepping tasks differ between people with hip OA and healthy older adults?MethodsParticipants included 20 people with unilateral hip OA and 20 age-and sex-matched controls. Muscle activity in the three segments within GMed and two segments of GMin were examined using intramuscular electromyography during step-up, step-down and side-step tasks.ResultsParticipants in the OA group demonstrated reduced muscle activity early in the step-up task and a later time to peak activity in most muscle segments. Greater activity was identified in anterior GMin in people with hip OA during the side-step task. A delay in time to peak activity was identified in most muscle segments in people with OA during the side-step task.SignificanceFor participants with OA, reduced activity in most muscle segments and increased time spent in double limb stance during the step-up task could reflect the decreased strength and pain associated with single limb stance on the affected limb. This study provides further evidence of altered function of the deep gluteal muscles in people with hip OA and highlights the importance of addressing these muscles in rehabilitation.     

Muscle contributions to propulsion and braking during walking and running: Insight from external force perturbations

There remains substantial debate as to the specific contributions of individual muscles to center of mass accelerations during walking and running. To gain insight, we altered the demand for muscular propulsion and braking by applying external horizontal impeding and aiding forces near the center of mass as subjects walked and ran on a treadmill. We recorded electromyographic activity of the gluteus maximus (superior and inferior portions), the gluteus medius, biceps femoris, semitendinosus/membrinosus, vastus medialis, lateral and medial gastrocnemius and soleus. We reasoned that activity in a propulsive muscle would increase with external impeding force and decrease with external aiding force whereas activity in a braking muscle would show the opposite. We found that during walking the gastrocnemius and gluteus maximus provide propulsion while the vasti are central in providing braking. During running, we found that the gluteus maximus, vastus medialis, gastrocnemius and soleus all contribute to propulsion.     

Relationship between iliotibial band syndrome and hip neuromechanics in women runners

BackgroundAtypical frontal plane hip kinematics are associated with iliotibial band syndrome in women runners. Gluteus medius is the primary muscle controlling the hip adduction angle during the loading response of stance. It is unclear if differences exist in gluteus medius activity magnitude and activity duration between runners with previous iliotibial band syndrome and controls. Furthermore, hip neuromechanics may change after a prolonged run.Research QuestionDo differences exist in the hip adduction angle and gluteus medius activity between women with previous iliotibial band syndrome and controls at the beginning and end of a 30-minute moderate paced treadmill run?MethodsThirty women participated (n = 15 controls). Lower extremity kinematics and gluteus medius activity were recorded at the start and end of a 30-minute treadmill run at participants’ self-selected pace. Hip kinematics and gluteus medius activity were analyzed via separate two-way (group x time) mixed-model analysis of variance with time as the repeated measure.ResultsHip neuromechanics were similar at the start and end of a 30-minute treadmill run in women with previous iliotibial band syndrome and controls. However, hip adduction excursion was less in women with previous iliotibial band syndrome compared to controls. Average gluteus medius activity magnitude and activity duration were not significantly different between groups.SignificanceThese findings support the growing body of literature that smaller hip adduction motion is related to previous iliotibial band syndrome in women. Regardless of injury history, gluteus medius activity was similar between groups during the loading phase of stance.     

Effect of different walking speeds on joint and muscle force estimation using AnyBody and OpenSim

BackgroundTo be able to use muscluloskeletal models in clinical settings, it is important to understand the effect of walking speed on joint and muscle force estimations in different generic musculoskeletal models.Research questionThe aim of the current study is to compare estimated joint and muscle forces as a function of walking speed between two standard approaches offered in two different modelling environments (AnyBody and OpenSim).MethodsExperimental data of 10 healthy participants were recorded at three different walking speeds (self-selected, 25 % slower, 25 % faster) using a ten-camera motion capture system together with four force plates embedded into a ten-meter walkway. Joint compression forces and muscle forces were calculated with a generic model in AnyBody and OpenSim. Trend analyses, mean absolute error (MAE) and correlation coefficients were used to compare joint compression forces and muscle forces between the two approaches. A one-way and two-way ANOVA with repeated measures were used to compare MAE and trend analysis changes, respectively (α = 0.05, Bonferroni corrected post-hoc tests).ResultsTrend analyses showed the same speed effect for AnyBody and OpenSim. MAEs increased significantly from slow to fast walking for knee joint compression forces, biceps femoris long head, gluteus maximus, gluteus medius and vastus intermedius. Lower correlation coefficients during slower walking were found for quadriceps muscles, gluteus maximus and biceps femoris compared to normal and faster walking.SignificanceLower correlation coefficients during slower walking are assumed to be due to a higher amount of solutions solving the muscle recruitment in musculoskeletal models. This indicates that decreasing walking speed is more prone to speed dependent differences regarding variability, while the absolute error increased with increasing walking speed. To conclude, different modelling environments can react differently to changes in walking speed, but overall results are promising regarding the generalization across different generic musculoskeletal models.     

Changes in muscle activation patterns when running step rate is increased

Running with a step rate 5-10% greater than one's preferred can substantially reduce lower extremity joint moments and powers, and has been suggested as a possible strategy to aid in running injury management. The purpose of this study was to examine how neuromuscular activity changes with an increase in step rate during running. Forty-five injury-free, recreational runners participated in this study. Three-dimensional motion, ground reaction forces, and electromyography (EMG) of 8 muscles (rectus femoris, vastus lateralis, medial gastrocnemius, tibialis anterior, medial and lateral hamstrings, and gluteus medius and maximus) were recorded as each subject ran at their preferred speed for three different step rate conditions: preferred, +5% and +10% of preferred. Outcome measures included mean normalized EMG activity for each muscle at specific periods during the gait cycle. Muscle activities were found to predominantly increase during late swing, with no significant change in activities during the loading response. This increased muscle activity in anticipation of foot-ground contact likely alters the landing posture of the limb and the subsequent negative work performed by the joints during stance phase. Further, the increased activity observed in the gluteus maximus and medius suggests running with a greater step rate may have therapeutic benefits to those with anterior knee pain.     

Contraction of knee flexors and extensors in skiing related to the backward fall mechanism of injury to the anterior cruciate ligament

The purpose of this study was to examine the motion pattern and muscle activity during jumping and landing in downhill skiing to estimate the muscular involvement during the jump-landing-backward fall-anterior cruciate ligament (ACL) injury. A digitized 2-D video motion analysis and a synchronous 8-channel electromyography registration was performed over a jump on a downhill slope during 3 runs by 2 skiers and during 6 control jumps in the laboratory. The knee flexors (lateral gastrocnemius and biceps femoris) were recruited before touchdown and mean 60 ms earlier than the extensors (vastus lateralis and rectus femoris). Extensors and flexors reached peak activity simultaneously at the instant of landing. The knee flexion angle at the instant of landing was mean 36°. As the landing was stabilized, the extensor activity persisted during eccentric work at increasing knee flexion as a corresponding flexor relaxation took place. The control jump in the laboratory showed a similar order of recruitment and timing of muscle contraction. The gastrocnemius was recruited mean 96 ms earlier and the biceps femoris mean 63 ms earlier than the extensors. This recruitment pattern during the landing movement suggest a learned motor program engaging the kinetic chain of the lower extremity to intercept the landing energy. The results also indicate that the knee flexor activity may protect the ACL at the instant of landing but that it is minimal shortly thereafter and probably not able to protect the ACL when a backward fall occurs. The knee was flexed substantially as the extensors became the dominating muscles. Thus, their ability to apply any anterior drawer force able to rupture the ACL is questioned.     

Hip muscle activity in male football players with hip-related pain; a comparison with asymptomatic controls during walking

ObjectivesCompare muscle activity between male football players with and without hip-related pain. Morphological and intra-articular features of hip-related pain are proposed pre-cursors to hip osteoarthritis. Altered muscle activity is a feature of severe hip osteoarthritis, but it is not known whether differences exist earlier in the pathological spectrum.DesignCross-sectional;SettingUniversity laboratory;ParticipantsForty-two male football players with hip-related pain; and 19 asymptomatic controls.Main outcome measuresHip muscle activity (Gluteus maximus, gluteus medius, tensor facia latae, adductor longus and rectus femoris) was recorded during walking using surface electromyography (EMG).ResultsMen with hip-related pain had sustained rectus femoris activity prior to toe-off (47–51% of the gait cycle) (p = 0.01, ES = 0.51) unlike controls who had reduced activity. In men with severe hip-related pain, gluteus maximus EMG was sustained into mid-stance (12–20% of the gait cycle) (F = 6.15, p < 0.01) compared to controls.ConclusionsDifferences in rectus femoris and gluteus maximus activity were identified between male footballers with and without hip-related pain. The pattern of gluteus maximus EMG relative to peak, approaching mid-stance in severe hip-related pain, is consistent with observations in severe hip osteoarthritis. This supports the hypothesis that symptom severity may influence muscle activity across the spectrum of hip degeneration.     

The biomechanics of running in athletes with previous hamstring injury: A case‐control study

Hamstring injury is prevalent with persistently high reinjury rates. We aim to inform hamstring rehabilitation by exploring the electromyographic and kinematic characteristics of running in athletes with previous hamstring injury. Nine elite male Gaelic games athletes who had returned to sport after hamstring injury and eight closely matched controls sprinted while lower limb kinematics and muscle activity of the previously injured biceps femoris, bilateral gluteus maximus, lumbar erector spinae, rectus femoris, and external oblique were recorded. Intergroup comparisons of muscle activation ratios and kinematics were performed. Previously injured athletes demonstrated significantly reduced biceps femoris muscle activation ratios with respect to ipsilateral gluteus maximus (maximum difference ?12.5%, P = 0.03), ipsilateral erector spinae (maximum difference ?12.5%, P = 0.01), ipsilateral external oblique (maximum difference ?23%, P = 0.01), and contralateral rectus femoris (maximum difference ?22%, P = 0.02) in the late swing phase. We also detected sagittal asymmetry in hip flexion (maximum 8°, P = 0.01), pelvic tilt (maximum 4°, P = 0.02), and medial rotation of the knee (maximum 6°, P = 0.03) effectively putting the hamstrings in a lengthened position just before heel strike. Previous hamstring injury is associated with altered biceps femoris associated muscle activity and potentially injurious kinematics. These deficits should be considered and addressed during rehabilitation.     

Comparison of regional lower limb glucose metabolism in older adults during walking

Glucose metabolism in lower limb muscles during walking has an important role in gait efficiency and endurance. The purpose of this study was to identify differences in muscle activity during walking between healthy young and older adults using positron emission tomography (PET) and [¹⁸F]fluorodeoxyglucose (FDG). Ten healthy young men (24 ± 2 years) and 10 healthy older men (76 ± 2 years) participated in this study. An FDG PET assessment of each subject was conducted after 50 min of treadmill walking. The images of glucose metabolism in 18 regions of interest were estimated from the standardized uptake value (SUV). The older adults showed a significantly higher FDG uptake in the semitendinosus, biceps femoris, iliacus, gluteus minimus, gluteus medius, and gluteus maximus muscles than the young adults: FDG uptake ratios of SUV in the old to SUV in the young were 3.02, 3.19, 1.66, 1.64, 3.68, and 3.05, respectively. During walking, the FDG uptake in older adults was higher in hamstrings and deep layer hip muscles than that in young adults. These results suggest that intervention to facilitate efficient muscle activity during walking should be practiced to improve gait endurance in older adults with impaired walking patterns.