Gluteus Maximus Activity Research Articles

Effect of iliopsoas muscle tightness on electromyographic activity of hip extensor synergists during gait

Background: Hip flexor muscles' tightness has been considered as one of the main risk factors for neuromuscular impairment of lower extremities not only lead to change the movement patterns but also probably result in changing the neuromuscular features of other muscles. The purpose of this research is study was to evaluate the iliopsoas tightness’ effect on electromyographic activity of hip extensor synergists during gait. Methods: In this case-control study fifteen 11-14 years old adolescents with iliopsoas tightness as experimental group, and 15 healthy adolescents which matched based on age, height, weight, body mass index, dominant leg and sport experience participated voluntarily as control group. Surface electromyographic activity of the gluteus maximus, adductor magnus and biceps femoris, were measured between groups during stance phase of gait. Results: Individuals with restricted hip flexor muscle length demonstrated more gluteus maximus activation during terminal stance (p=.001), more biceps femoris activation during mid stance (p=.002) and late stance (p=.001) and more adductor magnus activation during mid stance (p=.04) and late stance (p=.001). Conclusion: Adolescent soccer athletes with hip flexor muscle tightness exhibit more biceps femoris and adductor magnus and gluteus maximus activation during stance phase of gait. Thus, individuals with hip flexor muscle tightness appear to utilize different neuromuscular strategies to control lower extremity motion.

Novel Assessment of Isometric Hip Extensor Function: Reliability, Joint Angle Sensitivity, and Concurrent Validity.

Goodwin, JE and Bull, AMJ. Novel assessment of isometric hip extensor function: reliability, joint angle sensitivity, and concurrent validity. J Strength Cond Res 36(10): 2762-2770, 2022-Closed-chain hip extension function has not been well examined. The aim of this study was to examine the reliability, joint angle sensitivity, muscle recruitment, and concurrent validity of a force plate-based isometric hip extensor test (isometric hip thrust). All subjects were active men aged 19-29 years. In part 1, bilateral and unilateral hip extensor testing was completed on 4 occasions by 14 subjects to evaluate repeatability of force and torque measures. In part 2, joint angle sensitivity of force, torque, and surface electromyography was assessed by 10 subjects completing testing at 4 hip joint angles in a single test session. In part 3, concurrent validity of joint torque was assessed relative to standing and supine test positions on an isokinetic dynamometer, by 10 subjects in a single test session. The repeatability study found small changes in the mean from sessions 1-2 (mean standardized change d = 0.31) and close to no change in later sessions (mean d = 0.12). Typical error was predominantly low to moderate (mean 0.42), and intraclass correlation coefficient (ICC) was typically high (mean ICC = 0.87). The joint angle sensitivity study showed that increasing the hip flexion resulted in increases in peak extension force ( p = 0.001) and gluteus maximus activation ( p = 0.003) and a reduction in biceps femoris activation ( p < 0.001). There was no change in torque ( p = 0.585) and vastus lateralis activation ( p = 0.482). The concurrent validity study found that torque was correlated with supine dynamometry ( R2 = 0.555) but not with standing dynamometry ( R2 = 0.193). In summary, the isometric hip thrust is repeatable, but benefits from familiarization. Force output and muscle recruitment are sensitive to joint position, providing an opportunity to assess different functional output.

Multi-joint biomechanics during sloped walking in patients with developmental dysplasia of the hip

BackgroundDevelopmental dysplasia of the hip is characterized by abnormal acetabular and femoral geometries that alter joint loading and increase the risk of hip osteoarthritis. Current understanding of biomechanics in this population remains isolated to the hip and largely focused on level-ground walking, which may not capture the variable loading conditions that contribute to symptoms and intra-articular damage. MethodsThirty young adult females (15 with dysplasia) underwent gait analysis during level, 10° incline, and 10° decline walking while whole-body kinematics, ground reaction forces, and electromyography (EMG) were recorded. Low back, hip, and knee joint kinematics and internal joint moments were calculated using a 15-segment model and integrated EMG was calculated within the functional phases of gait. Dependent variables (peak joint kinematics, moments, and integrated EMG) were compared across groups with a one-way ANOVA with multiple comparisons controlled for using the Benjamini-Hochberg method (α = 0.05). FindingsDuring level and incline walking, patients with developmental dysplasia of the hip had significantly lower trunk flexion angles, lumbar and knee extensor moments, and erector spinae activity than controls. Patients with developmental dysplasia of the hip also demonstrated reduced rectus femoris activity during loading of level walking and increased gluteus maximus activity during mid-stance of decline walking. InterpretationPatients with developmental dysplasia of the hip adopt compensations both proximal and distal to the hip, which vary depending on the slope of walking. Furthering the understanding of multi-joint biomechanical compensations is important for understanding the mechanism of osteoarthritis development as well as secondary conditions.

Is the Occurrence of the Sticking Region in Maximum Smith Machine Squats the Result of Diminishing Potentiation and Co-Contraction of the Prime Movers among Recreationally Resistance Trained Males?

This study compared the kinetics, barbell, and joint kinematics and muscle activation patterns between a one-repetition maximum (1-RM) Smith machine squat and isometric squats performed at 10 different heights from the lowest barbell height. The aim was to investigate if force output is lowest in the sticking region, indicating that this is a poor biomechanical region. Twelve resistance trained males (age: 22 ± 5 years, mass: 83.5 ± 39 kg, height: 1.81 ± 0.20 m) were tested. A repeated two-way analysis of variance showed that Force output decreased in the sticking region for the 1-RM trial, while for the isometric trials, force output was lowest between 0–15 cm from the lowest barbell height, data that support the sticking region is a poor biomechanical region. Almost all muscles showed higher activity at 1-RM compared with isometric attempts (p < 0.05). The quadriceps activity decreased, and the gluteus maximus and shank muscle activity increased with increasing height (p ≤ 0.024). Moreover, the vastus muscles decreased only for the 1-RM trial while remaining stable at the same positions in the isometric trials (p = 0.04), indicating that potentiation occurs. Our findings suggest that a co-contraction between the hip and knee extensors, together with potentiation from the vastus muscles during ascent, creates a poor biomechanical region for force output, and thereby the sticking region among recreationally resistance trained males during 1-RM Smith machine squats.

Lunges activate the gluteus maximus muscles more than back squats when both exercises are standardized

BACKGROUND: Squats are considered one of the main exercises for the lower limbs and are used in resistance training under different contexts, including rehabilitation and sports performance. OBJECTIVE: To compare the EMG activity of different muscles in back squat and lunge exercises in trained women. METHODS: Ten healthy women experienced in resistance training performed back squat and lunge exercises on a Smith machine (total work: 70% of 1RM, 1 set, 10 repetitions and 2-s/2-s of execution speed) with an interval of 20-min between exercises. Both exercises were standardized in relation to the trunk inclination and were performed with an erect trunk parallel to the cursor of the guided bar. RESULTS: The EMG activity of the vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), and gluteus maximus (GM) were analyzed. There were no significant differences in the EMG activity of the VM, VL, and BF muscles between the back squat and lunge exercises (P&gt; 0.05); however, GM activation was greater during the lunge exercise (effect size = 1.15; P= 0.001). CONCLUSIONS: Lunges were more effective in recruiting the GM when compared to back squats. However, both exercises can be recommended when the goal is knee extensor and flexor muscle activity.

Trunk and hip muscles activation patterns in subjects with and without chronic low back pain: a systematic review

The purpose of this study was to determine normal and abnormal patterns of activation of gluteus maximus (GM), hamstring (HAM), contralateral erector spinae (CES), and ipsilateral erector spinae (IES) muscles during a prone hip extension test in healthy or asymptomatic subjects and those with non-specific chronic low back pain through a systematic review. Studies were recognized by searching electronic databases (Embase, MEDLINE/PubMed, Cochrane Library, PEDro [Physiotherapy Evidence Database], and CINAHL) and scanning articles reference lists from the beginning until July 2018. Limits involved studies in the English language and performed among humans. Of 2112 citations and reference lists scanned, 15 articles were determined to be relevant to this review. From these studies, 4 investigated 157 subjects (88 asymptomatic and 69 with low back pain), and 11 investigated 257 healthy subjects. The results of the moderate and weak quality studies indicate that the HAM and ES muscles are activated early and almost simultaneously, but GM is consistently delayed in relation to leg movement and the other 3 muscles in healthy individuals. In low back pain subjects, CES are delayed and GM is significantly delayed in individuals who showed abnormal lumbar motions when compared with healthy ones.

Comparison of Glutues Maximus Activation to Flexion Bias Exercises Along with MET Technique in Subjects with Anterior Rotated Sacroiliac Joint Dysfunction—a Randomised Controlled Trial

Background: Sacroiliac joint dysfunction (SIJD) is the primary source of lowback pain. Main muscles forming the force closure of sacroiliac joint are the biceps femoris and gluteus maximus which increase the stability through massive attachments via sacrotuberous ligament. However, there is a dearth of literature of the importance of activation of gluteus maximus in SIJD. Purpose: To study the effect of gluteus maximus activation on Oswestry Disability Index (ODI), visual analog scale (VAS), and pelvic tilt angle in subjects with anterior rotated sacrolilac joint dysfunction. Settings: The study was conducted in outpatient Physiotherapy Department, Manipal Hospital, Bangalore, India. Participants: Anterior rotated SIJD subjects were recruited in the study. They were divided into two groups (experimental and control groups) by block randomisation. Research Design: This is a randomised control trial. Controlled Treatment: Treatment order was determined by block randomisation. The subjects of both experimental and control group received Muscle Energy Technique (MET) technique on 1st session to correct the anterior rotated SIJD. The experimental group received gluteus maximus activation protocol, whereas the control group received flexion bias exercises. The groups received the treatment of 20 mins per session. There were two supervised sessions per week for four weeks. Main Outcome Measures: The primary outcome measure in the study is Oswestry Disability Index (ODI). The secondary outcome measures included visual analog scale (VAS) and Palpation Meter (PALM). Results: 48 subjects (26 females, 22 males) were randomised into experimental and control groups having anterior rotation SIJD, and average age in groups was 38.83 ± 11.4 years and 34.96 ± 9.5 years, respectively. The within-group analysis showed significant improvements in only ODI outcome of both the groups (p = .001). The between-group analysis in both groups did not show any statistical significant difference in ODI, VAS, or PALM. Conclusion: The flexion bias exercise and the gluteus maximus activation exercises used in this study were equally effective in improving physical function and reduction in pain, and maintaining the normal pelvic angle in subjects with anterior rotated SIJD.

Comparative Analysis of the Electromyography Activity of Core Muscles During Balance Pad- and Sling-assisted Exercises

Background: Unstable surface-based core training can significantly enhance core strength, but no studies have compared the effects of balance pad- and sling-assisted exercises. Objects: To study the effects of unstable surface-based balance pad- and sling-assisted core strength exercises on muscle activity. Methods: Twenty male students aged 20-25 years participated in this study. The effects of three types of core strength exercises, performed with a sling or balance pad, on the activities of three muscles, i.e., the right musculus obliquus externus abdominis (EO), right erector spinae (ES), and right gluteus maximus (GM), were examined. Results: 1) In the glute bridge exercise, the percentage of maximum voluntary contraction of the EO, ES, and GM were significantly different between the balance pad- and sling-assisted exercises. The relative contribution of the ES and GM activities to all muscle activity were not significantly different between the two training types, whereas that for EO showed a significant difference. 2) There was no significant difference in the percentage value of maximum voluntary contraction (%MVC) among the EO, ES, and GM during the “leg-lifting with flat support”exercise, and there were no significant difference in the relative contributions between the two training types. 3) In the “side bridge leg separation exercise”, the %MVC of the ES, EO, and GM were significantly different between the two training types. Conclusion: Sling training for core muscles was generally better than balance pad assist training. The majority of physiotherapy patients require core training. Our results could guide physiotherapists in the choice of targeted exercises for these patients.

Wearable Sensors Detect Differences between the Sexes in Lower Limb Electromyographic Activity and Pelvis 3D Kinematics during Running.

Each year, 50% of runners suffer from injuries. Consequently, more studies are being published about running biomechanics; these studies identify factors that can help prevent injuries. Scientific evidence suggests that recreational runners should use personalized biomechanical training plans, not only to improve their performance, but also to prevent injuries caused by the inability of amateur athletes to tolerate increased loads, and/or because of poor form. This study provides an overview of the different normative patterns of lower limb muscle activation and articular ranges of the pelvis during running, at self-selected speeds, in men and women. Methods: 38 healthy runners aged 18 to 49 years were included in this work. We examined eight muscles by applying two wearable superficial electromyography sensors and an inertial sensor for three-dimensional (3D) pelvis kinematics. Results: the largest differences were obtained for gluteus maximus activation in the first double float phase (p = 0.013) and second stance phase (p = 0.003), as well as in the gluteus medius in the second stance phase (p = 0.028). In both cases, the activation distribution was more homogeneous in men and presented significantly lower values than those obtained for women. In addition, there was a significantly higher percentage of total vastus medialis activation in women throughout the running cycle with the median (25th–75th percentile) for women being 12.50% (9.25–14) and 10% (9–12) for men. Women also had a greater range of pelvis rotation during running at self-selected speeds (p = 0.011). Conclusions: understanding the differences between men and women, in terms of muscle activation and pelvic kinematic values, could be especially useful to allow health professionals detect athletes who may be at risk of injury.

Effects of Log-Rolling Position on Hip-Abductor Muscle Activation During Side-Lying Hip-Abduction Exercise in Participants With Gluteus Medius Weakness.

Weakness of the gluteus medius and gluteus maximus is associated with a variety of musculoskeletal disorders. However, activation of synergistic muscles that are not targeted should be considered when prescribing side-lying hip-abduction (SHA) exercises. Log-rolling positions may affect hip-abductor activity during SHA. To determine the effects of log-rolling positions on gluteus medius, gluteus maximus, and tensor fasciae latae activity during SHA in participants with gluteus medius weakness. Controlled laboratory study. University research laboratory. Twenty-one participants with gluteus medius weakness. Three types of SHA were performed: frontal-plane SHA in neutral position (SHA-neutral), frontal-plane SHA in anterior log-rolling position (SHA-anterior rolling), and frontal-plane SHA in posterior log-rolling position (SHA-posterior rolling). Surface electromyography was used to measure hip-abductor activity. One-way repeated-measures analysis of variance was calculated to assess the statistical significance of the muscle activity. The SHA-anterior rolling showed greater gluteus medius and gluteus maximus activation than the SHA-neutral (P = .003 and P < .001, respectively) and SHA-posterior rolling (P < .001 and P < .001, respectively). The SHA-neutral demonstrated greater gluteus medius and gluteus maximus activation than the SHA-posterior rolling (P < .001 and P = .001, respectively). The SHA-anterior rolling produced less tensor fasciae latae activation than the SHA-neutral (P < .001) and SHA-posterior rolling (P < .001). The SHA-neutral showed less tensor fasciae latae activation than the SHA-posterior rolling (P < .001). The SHA-anterior rolling may be an effective exercise for increasing activation of the gluteus medius and gluteus maximus while decreasing activation of the tensor fasciae latae in participants with gluteus medius weakness.

Lower Limb Muscles Activity and Inclined Squat Position in Normal Children (Cross Sectional Study)

Background: Benefits associated with squat performance are not limited to the athletic population. Given that most activities of daily living necessitate the simultaneous coordinated interaction of numerous muscle groups, the squat is considered one of the best exercises for improving quality of life because of its ability to recruit multiple muscle groups in a single maneuver. Objective: To determine the effect of inclined squat position on the vastus medialis oblique (VMO) and gluteus maximus (GM) at the different ankle angles 5°-10° degrees of inclination in normal children. Subjects and methods: thirty non-athletic children of both genders, age ranged from 14 to 18 years, were selected from the Egyptian governmental schools at Sixth of October City and Sixth of October Sporting Club. The maximum voluntary isometric contraction (MVIC) was measured after the electrodes were attached to the GM and the VMO of the subject during squat postures which applied on two inclined borders 5 and 10 degree of inclination; the feet are spread out shoulder width, hip 70° flexion, knee 75° flexion and in the erect posture. Results: There was a significant increase in the VMO activity in 5° ankle angle compared with that of 10° ankle angle (p = 0.0001). There was a significant decrease in the GM activity in 5° ankle angle compared with that of 10° ankle angle (p = 0.0001). Conclusion: modification of ankle dorsiflexion during squat position should be integrated in the rehabilitation programs of the different injuries.

Lower Limb Muscles Activity and Inclined Squat Position in Normal Children (Cross Sectional Study)

Background: Benefits associated with squat performance are not limited to the athletic population. Given that most activities of daily living necessitate the simultaneous coordinated interaction of numerous muscle groups, the squat is considered one of the best exercises for improving quality of life because of its ability to recruit multiple muscle groups in a single maneuver. Objective: To determine the effect of inclined squat position on the vastus medialis oblique (VMO) and gluteus maximus (GM) at the different ankle angles 5°-10° degrees of inclination in normal children. Subjects and methods: thirty non-athletic children of both genders, age ranged from 14 to 18 years, were selected from the Egyptian governmental schools at Sixth of October City and Sixth of October Sporting Club. The maximum voluntary isometric contraction (MVIC) was measured after the electrodes were attached to the GM and the VMO of the subject during squat postures which applied on two inclined borders 5 and 10 degree of inclination; the feet are spread out shoulder width, hip 70° flexion, knee 75° flexion and in the erect posture. Results: There was a significant increase in the VMO activity in 5° ankle angle compared with that of 10° ankle angle (p = 0.0001). There was a significant decrease in the GM activity in 5° ankle angle compared with that of 10° ankle angle (p = 0.0001). Conclusion: modification of ankle dorsiflexion during squat position should be integrated in the rehabilitation programs of the different injuries.

Optimal Patient Position to Maximize Gluteus Maximus Activation During Prone Hip Extension: A Critically Appraised Topic

Clinical Question: What is the most optimal position to perform the prone hip extension exercise in order to improve the gluteus maximus to hamstring activation ratio? Clinical Bottom Line: There does not appear to be a specific position recommended to perform the prone hip extension exercise in order to activate the gluteus maximus over the hamstrings.

Exploring infant hip position and muscle activity in common baby gear and orthopedic devices.

Infant positioning in daily life may affect hip development. While neonatal animal studies indicate detrimental relationships between inactive lower extremities and hip development and dysplasia, no research has explored infant hip biomechanics experimentally. This study evaluated hip joint position and lower extremity muscle activity of healthy infants in common body positions, baby gear, and orthopedic devices used to treat hip dysplasia (the Pavlik harness and the Rhino cruiserabduction brace). Surface electromyography(EMG) and marker-based motion capture recorded lower extremity muscle activity and kinematics of 22 healthy full-term infants (4.2±1.6 months, 13M/9F) during five conditions: Pavlik harness, Rhino brace, inward-facing soft-structured baby carrier, held in arms facing inwards, and a standard car seat. Mean filtered EMG signal, time when muscles were active, and hip position (angles) were calculated. Compared to the Pavlik harness, infants exhibited similar adductor activity (but lower hamstring and gluteus maximus activity) in the Rhino abduction brace, similar adductor and gluteus maximus activity (but lower quadriceps and hamstring activity) in the baby carrier, similar but highly variable muscle activity in-arms, and significantly lower muscle activity in the car seat. Hip position was similar between the baby carrier and the Pavlik harness. This novel infant biomechanics study illustrates the potential benefits of using inward-facing soft-structured baby carriers for healthy hip development and highlights the potential negative impact of using supine-lying container-type devices such as car seats for prolonged periods of time. Further study is needed to understand the full picture of how body position impacts infant musculoskeletal development.

Hip Angles, Joint Moments, and Muscle Activity During Gait in Women With and Without Self-reported Stress Urinary Incontinence

Background: Women with stress urinary incontinence (SUI) have different hip strength, mobility, and unique between-leg differences compared with women without SUI. This article describes gait biomechanics in these same women to provide insight into their function and neuromuscular system. Objective: To compare gait biomechanics between women with and without self-reported SUI. Study Design: Descriptive. Methods: Hip angles, moments (net forces), and muscle activity were analyzed during 3 phases of stance (weight acceptance [WA], mid-stance [MS], and terminal stance [TS]), using 3-dimensional cameras, force plates, and surface electromyography. Values were compared between groups (SUI, n = 21; no SUI, n = 20) and limbs (dominant, D; nondominant, ND) (significance: P ≤ .05). Results: Between-Group Comparisons: Both limbs in the SUI group had greater abduction (ABD) moments (WA: D: P = .039; ND: P = .030), external rotation (ER) moments (WA: D: P = .002, ND: P = .004; and MS: D: P = .033, ND: P = .035), and gluteus maximus activity (TS: D: P < .001, ND: P = .005). The SUI group's ND-limb had greater adduction angles (WA: P = .043), internal rotation (IR) angles (WA: P = .011; MS: P = .028), flexion (FL) moments (TS: P = .050), and tensor fasciae latae activity (TS: P = .044). The SUI group's D-limb had greater ABD moments (TS: P = .034). Between-Limb Comparisons Unique to Each Group: The SUI group's ND-limb had greater IR angles (WA: P = .007, MS: P = .032, TS: P = .027), relative lesser ER angles (MS: P = .003, TS: P = .007), and lesser FL angles (MS: P = .029). The without SUI group's ND-limb had greater ER moments (MS: P = .022). Conclusions: Women with SUI demonstrate unique gait mechanics, predominantly in the transverse plane and in the ND-limb. A video abstract for this article is available at: https://links.lww.com/JWHPT/A29.

COMPARATIVE ANALYSIS OF HIP MUSCLE ACTIVATION DURING CLOSED-CHAIN REHABILITATION EXERCISES IN RUNNERS

Increased hip adduction and internal rotation during the early stance phase of running have been linked to an increased risk of lower extremity injury. Both the gluteus maximus (GMAX) and gluteus medius (GMED) eccentrically control these motions. GMAX and GMED activation levels during commonly used rehabilitation exercises requires further exploration. The purpose of this study was to compare peak surface electromyography (sEMG) amplitudes of GMAX and GMED between three closed-chain rehabilitation exercises: bilateral hip external rotation with resistance band (BER), forward lunge with resistance band (FL), and single-leg rotational squat (SLS). It was hypothesized that the FL would elicit greater peak amplitude in the GMAX and GMED than SLS and BER. Descriptive, observational cohort study. Twenty-two healthy runners (14 male, 8 female) had sEMG electrodes placed bilaterally on GMAX and GMED. Participants completed three repetitions each of BER, FL, and SLS exercises with sEMG data normalized to the maximal amplitude recorded at each muscle during the running trial (% MRC). Seven inertial measurement units affixed to the lower extremity measured joint kinematics to enable the exercises to be split into eccentric and concentric phases respectively. There were no significant differences between exercises during the eccentric phases with all peak amplitudes for GMAX and GMED being less than < 30% MRC. Both the SLS (GMAX: 48.2 ± 45.2% MRC, p = 0.019; GMED: 39.3 ± 24.8% MRC, p < .001) and FL (GMAX: 65.8 ± 58.9% MRC, p < .001; GMED: 52.2 ± 34.9% MRC, p<.001) elicited significantly greater peak amplitudes than BER (GMAX: 21.7 ± 22.3% MRC; GMED: 22.8 ± 21.2% MRC) during the concentric phase. Running related injuries have been linked to deficits in GMAX and GMED activation and strength. When averaged bilaterally across 22 healthy runners, peak GMAX and GMED amplitudes during three weight bearing exercises were less than 70% MRC. All three exercises had comparable eccentric peak amplitudes; however, the BER exercise produced a significantly reduced GMAX and GMED amplitude during the concentric phase versus the FL and SLS. The FL and SLS appear equally effective at eliciting peak GMAX and GMED activation. 3.

Gluteus medius dysfunction in females with chronic ankle instability is consistent at different walking speeds

BackgroundPatients with chronic ankle instability often present with altered gait mechanics compared to ankle sprain copers. There is increasing evidence to suggest proximal neuromuscular alterations contribute to the injury etiology, however little is known about how these changes manifest during gait. The purpose of this study was to investigate ipsilateral gluteus maximus and medius functional activity ratios throughout treadmill walking at three speeds (preferred, 120% preferred, and 1.35 m per second) in chronic ankle instability patients compared to copers. Methods28 females (14 chronic ankle instability, 14 copers) walked at the three gait speeds in randomized order. Ground reaction forces and 10-s gluteal ultrasound clips were simultaneously recorded. Clips were reduced using ground reaction forces to extract 55 measurement frames. Normalized gluteal thickness measures were used to determine functional activity ratios. 2 × 3 analyses of variance were run to assess group and speed effects on gluteal outcomes throughout walking using statistical parametric mapping. Post-hoc t-tests, mean differences, and Cohen's d effect sizes were assessed for significant findings (P ≤ .05). FindingsThe chronic ankle instability group had significantly decreased gluteus medius activity throughout the entire gait cycle when compared to the coper group, independent of gait speed (P < .001, mean differences: 0.10–0.18; d: 1.00–3.17). There were no significant group or speed main effects, nor an interaction for gluteus maximus activity. InterpretationGluteal dysfunction throughout walking was identified in chronic ankle instability. The coper group remained within healthy reference muscle activity ranges, suggesting that proximal muscle activation alterations are associated chronic ankle impairments.

Differences in Gluteal and Quadriceps Muscle Activation Among Adults With and Without Lumbar Hyperlordosis.

Many factors have been reported contributing to altering the neuromuscular function of hip and knee muscles. The lumbar hyperlordosis, as a poor posture in some athletes, is thought to be associated with the alteration of the hip and knee muscles activity. To examine the activation of selected hip and knee muscles in athletes with and without lumbar hyperlordosis during functional activities. Case-control study. University laboratory. Twenty-six college male athletes (n = 13 with and n = 13 without lumbar hyperlordosis). Surface electromyography of gluteus maximus (GMAX), gluteus medius (GMED), vastus medialis oblique (VMO), and vastus lateralis (VL) were recorded during single-leg squat and single-leg jump landing (SLJL) tasks. Preactivity; reactivity; and onset muscle during SLJL and eccentric activity during single-leg squat (GMAX, GMED, VMO, and VL along with the ratio of VMO:VL) were assessed. Athletes with lumbar hyperlordosis had a higher level of activity in their GMAX (P = .003), VMO (P = .04), and VL (P = .01) muscles at the moment before foot contact during SLJL. These athletes also demonstrated a higher level of GMAX activity (P = .01) immediately after foot contact. Finally, athletes with lumbar hyperlordosis activated their GMAX sooner (P = .02) during the SLJL. Athletes with normal lumbar lordosis had more activity in their GMED muscle (P = .001) in the descending phase of the single-leg squat task and a higher VMO:VL (P = .01) at the moment after the foot contact during the SLJL. The altered activation of GMAX, GMED, VMO, VL, and VMO:VL can reveal the role of lumbar hyperlordosis in the knee and hip muscles' alteration in athletes. Further study is needed to identify whether these alterations in the hip and knee muscles contribute to injury in athletes.

The influences of restricted compensatory movement on activation pattern of gluteal muscles during unilateral weight-bearing exercise

We investigated changes in lateral pelvic tilt and activity of the gluteal muscles during one-leg standing with and without pressure biofeedback. Seventeen participants performed one-leg standing tests with pressure biofeedback (the threshold was set to the minimum change in pressure) and without biofeedback (standard one-leg standing). The lateral pelvic tilt was significantly lower in one-leg standing with pressure biofeedback than in standard one-leg standing ( p < .05). In addition, gluteus medius and gluteus maximus activity was significantly greater during one-leg standing with pressure biofeedback than during standard one-leg standing ( p < .05). Based on our results, restriction of compensatory movement can be used to increase activity of gluteal muscles when performing unilateral weight-bearing exercise such as one-leg standing.

Simultaneous ice and transcutaneous electrical nerve stimulation decrease anterior knee pain during running but do not affect running kinematics or associated muscle inhibition

BackgroundRunners often experience anterior knee pain and this pain is associated with altered running neuromechanics. The purpose of this study was to examine potential therapeutic benefits (reduced pain and restored running neuromechanics) of simultaneously applied ice and transcutaneous electrical nerve stimulation on experimentally-induced anterior knee pain. MethodsNineteen healthy subjects completed a sham and treatment data collection session. For both sessions, hypertonic saline was infused into the infrapatellar fat pad for approximately 80 min to induce experimental anterior knee pain. Perceived pain levels were measured every two minutes and running neuromechanics were recorded at four time points: pre-pain, pain before treatment, pain immediately post-treatment, and pain 20 min post-treatment. FindingsThe saline infusion significantly increased perceived knee pain from 0 to 2.8 cm. The ice/transcutaneous electrical nerve stimulation treatment significantly reduced perceived knee pain by 35%, six minutes after the treatment initiation. Perceived knee pain remained reduced until eight minutes after the treatment termination. The knee pain significantly decreased peak gluteus medius, vastus lateralis, and vastus medialis activation during running, each by an average of 17% plus/minus 6%; however, none of these decreases were resolved via the therapeutic treatment. Neither the knee pain nor the therapeutic treatment significantly affected peak gluteus maximus activation or peak hip adduction angle. InterpretationThe experimental pain model effectively produced anterior knee pain and decreased muscle activation during running. The simultaneous ice/transcutaneous electrical nerve stimulation treatment effectively decreased anterior knee pain, but did not restore running neuromechanics that were altered due to the pain.