scholarly journals Gluteal Muscle Atrophy and Increased Intramuscular Lipid Concentration Are Not Mitigated by Daily Artificial Gravity Following 60-Day Head-Down Tilt Bed Rest

2021 ◽  
Vol 12 ◽  
Author(s):  
Vienna Tran ◽  
Enrico De Martino ◽  
Julie Hides ◽  
Gordon Cable ◽  
James M. Elliott ◽  
...  
Keyword(s):  
Hip Joint ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Bed Rest ◽  
Artificial Gravity ◽  
Control Group ◽  
Joint Stability ◽  
Lipid Concentration ◽  
Gluteal Muscle ◽  
Intramuscular Lipid

Exposure to spaceflight and head-down tilt (HDT) bed rest leads to decreases in the mass of the gluteal muscle. Preliminary results have suggested that interventions, such as artificial gravity (AG), can partially mitigate some of the physiological adaptations induced by HDT bed rest. However, its effect on the gluteal muscles is currently unknown. This study investigated the effects of daily AG on the gluteal muscles during 60-day HDT bed rest. Twenty-four healthy individuals participated in the study: eight received 30 min of continuous AG; eight received 6 × 5 min of AG, interspersed with rest periods; eight belonged to a control group. T1-weighted Dixon magnetic resonance imaging of the hip region was conducted at baseline and day 59 of HDT bed rest to establish changes in volumes and intramuscular lipid concentration (ILC). Results showed that, across groups, muscle volumes decreased by 9.2% for gluteus maximus (GMAX), 8.0% for gluteus medius (GMED), and 10.5% for gluteus minimus after 59-day HDT bed rest (all p < 0.005). The ILC increased by 1.3% for GMAX and 0.5% for GMED (both p < 0.05). Neither of the AG protocols mitigated deconditioning of the gluteal muscles. Whereas all gluteal muscles atrophied, the ratio of lipids to intramuscular water increased only in GMAX and GMED muscles. These changes could impair the function of the hip joint and increased the risk of falls. The deconditioning of the gluteal muscles in space may negatively impact the hip joint stability of astronauts when reexpose to terrestrial gravity.

scholarly journals Lumbar muscle atrophy and increased relative intramuscular lipid concentration are not mitigated by daily artificial gravity after 60-day head-down tilt bedrest

2021 ◽  
Author(s):  
Enrico De Martino ◽  
Julie Hides ◽  
James M. Elliott ◽  
Mark Hoggarth ◽  
Jochen Zange ◽  
...  
Keyword(s):  
Lumbar Spine ◽  
Intervertebral Disc ◽  
Muscle Atrophy ◽  
Bed Rest ◽  
Artificial Gravity ◽  
Lipid Concentration ◽  
Muscle Composition ◽  
Disc Area ◽  
Intramuscular Lipid ◽  
Water Ratio

Exposure to axial unloading induces adaptations in paraspinal muscles, as shown after spaceflights. This study investigated whether daily exposure to artificial gravity (AG) mitigated lumbar spine flattening and muscle atrophy associated with 60-day head-down tilt (HDT) bed rest (Earth-based space analogue). Twenty-four healthy individuals participated in the study: Eight received 30 minutes continuous AG; eight received 6x5 minutes AG, interspersed with rest periods; eight received no AG exposure (control group). Magnetic Resonance Imaging (MRI) of the lumbopelvic region was conducted at baseline (BDC) and at day 59 of HDT (HDT59). T1-weighted images were used to assess morphology of the lumbar spine (spinal length, intervertebral disc angles, disc area) and volumes of the lumbar multifidus (LM), lumbar erector spinae (LES), quadratus lumborum (QL), and psoas major (PM) muscles from L1/L2 to L5/S1 vertebral levels. A chemical shift-based 2‐point lipid/water Dixon sequence was used to evaluate muscle composition. Results showed that: spinal length and disc area increased (P<0.05); intervertebral disc angles (P<0.05) and muscle volumes of LM, LES, and QL reduced (P<0.01); and fat/water ratio for the LM and LES muscles increased (P<0.01) after HDT59 in all groups. Neither of the AG protocols mitigated the lumbar spinal deconditioning induced by HDT bed rest. The increase in lipid/water ratio in LM and LES muscles indicates an increased relative intramuscular lipid concentration. Altered muscle composition in atrophied muscles may impair lumbar spine function after body unloading, which could increase injury risk to vulnerable soft tissues. This relationship needs further investigation.

Modifications of Buttock Augmentation

1997 ◽  
Vol 14 (4) ◽  
pp. 405-411 ◽  
Author(s):  
Nikolas V. Chugay
Keyword(s):  
Traditional Method ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Bed Rest ◽  
Lower Portion ◽  
New Technique ◽  
Risk Of Infection ◽  
Anal Region ◽  
Secondary Infections ◽  
Recovery Times

The traditional method of buttock enlargement, which involves making an incision in the lower portion of the buttocks in the infragluteal fold, frequently results in secondary infections and long recovery times. Because of the proximity of the incision to the rectum and the pressure on the incision, the patient usually requires several days of bed rest. In some instances, it is necessary to remove an otherwise satisfactory implant to correct an infection. The author has overcome this problem by placing the incision in the center of the buttock in the intergluteal fold. A custom-designed solid silicon prosthesis is then placed between the gluteus medius and the gluteus maximus in a space provided by the anatomical design of these two large muscles. The gluteus also provides a good sling for the prosthesis, thus preventing future drooping of the prosthesis. More than 20 buttock enlargements have been successfully performed using this technique with no major complications. Use of this new technique decreases the risk of infection from the anal region and produces a softer, more natural look. This technique is also resistant to possible rupture such as may occur with a nonsolid gel silicone augmentation.

scholarly journals Movements in Different Hip Joint Positions Affect Gluteus Maximus and Gluteus Medius Muscle Activities

2014 ◽  
Vol 29 (6) ◽  
pp. 857-860
Author(s):  
Toshiaki SEKO ◽  
Tsuneo KUMAMOTO ◽  
Yui TAKAHASHI ◽  
Ryousuke KANEKO ◽  
Masashi TANAKA ◽  
...  
Keyword(s):  
Hip Joint ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Gluteus Medius Muscle

Hip Joint Contact Forces During Running with a Transtibial Amputation

2020 ◽  
Author(s):  
Lauren Sepp ◽  
Brian S Baum ◽  
Erika Nelson-Wong ◽  
Anne Silverman
Keyword(s):  
Hip Joint ◽  
Hip Osteoarthritis ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Contact Forces ◽  
Musculoskeletal Models ◽  
Joint Health ◽  
Joint Contact ◽  
Reaction Forces

Abstract People with unilateral transtibial amputations (TTA) have greater risks of bilateral hip osteoarthritis, related to asymmetric biomechanics compared to people without TTA. Running is beneficial for physical health and is gaining popularity. However, people with TTA may not have access to running-specific prostheses (RSPs), which are designed for running, and may instead run using their daily-use prosthesis (DUP). Differences in joint loading may result from prosthesis choice, thus it is important to characterize changes in peak and impulsive hip joint contact loading during running. Six people with and without TTA ran at 3.5 m/s while ground reaction forces, kinematics, and electromyography were collected. People with TTA ran using their own RSP and repeated the protocol using their own DUP. Musculoskeletal models incorporating prosthesis type of each individual were used to quantify individual muscle forces and hip joint contact forces during running. People using RSPs had smaller bilateral peak hip joint contact forces compared to when wearing DUPs during stance and swing, and a smaller impulse over the entire gait cycle. Greater amputated leg peak hip joint contact forces for people wearing DUPs compared to RSPs occurred with greater forces from the ipsilateral gluteus maximus during stance. People with TTA also had greater bilateral peak hip joint contact forces during swing compared to people without TTA, which occurred with greater peak gluteus medius forces. Running with more compliant RSPs may be beneficial for long-term joint health by reducing peak and impulsive hip loading compared to DUPs.

Relationship Between Gluteal Muscle Strength, Corticospinal Excitability, and Jump-Landing Biomechanics in Healthy Women

2013 ◽  
Vol 22 (4) ◽  
pp. 239-247 ◽  
Author(s):  
Adam S. Lepley ◽  
Allison M. Strouse ◽  
Hayley M. Ericksen ◽  
Kate R. Pfile ◽  
Phillip A. Gribble ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Outcome Measures ◽  
Motor Evoked Potentials ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Corticospinal Excitability ◽  
Gluteal Muscle ◽  
Jump Landing ◽  
Healthy Women ◽  
Landing Biomechanics

Context:Components of gluteal neuromuscular function, such as strength and corticospinal excitability, could potentially influence alterations in lower extremity biomechanics during jump landing.Objective:To determine the relationship between gluteal muscle strength, gluteal corticospinal excitability, and jump-landing biomechanics in healthy women.Setting:University laboratory.Design:Descriptive laboratory study.Participants:37 healthy women (21.08 ± 2.15 y, 164.8 ± 5.9 cm, 65.4 ± 12.0 kg).Interventions:Bilateral gluteal strength was assessed through maximal voluntary isometric contractions (MVIC) using an isokinetic dynamometer. Strength was tested in the open chain in prone and side-lying positions for the gluteus maximus and gluteus medius muscles, respectively. Transcranial magnetic stimulation was used to elicit measures of corticospinal excitability. Participants then performed 3 trials of jump landing from a 30-cm box to a distance of 50% of their height, with an immediate rebound to a maximal vertical jump. Each jump-landing trial was video recorded (2-D) and later scored for errors.Main Outcome Measures:MVICs normalized to body mass were used to assess strength in the gluteal muscles of the dominant and nondominant limbs. Corticospinal excitability was assessed by means of active motor threshold (AMT) and motor-evoked potentials (MEP) elicited at 120% of AMT. The Landing Error Scoring System (LESS) was used to evaluate jump-landing biomechanics.Results:A moderate, positive correlation was found between dominant gluteus maximus MEP and LESS scores (r = .562, P = .029). No other significant correlations were observed for MVIC, AMT, or MEP for the gluteus maximus and gluteus medius, regardless of limb.Conclusions:The findings suggest a moderate relationship between dominant gluteus maximus corticospinal excitability and a clinical measure of jump-landing biomechanics. Further research is required to substantiate the findings and expand our understanding of the central nervous system’s role in athletic movement.

Muscle Activation Levels of the Gluteus Maximus and Medius During Standing Hip-Joint-Strengthening Exercises Using Elastic-Tubing Resistance

2014 ◽  
Vol 23 (1) ◽  
pp. 1-11 ◽  
Author(s):  
James W. Youdas ◽  
Kady E. Adams ◽  
John E. Bertucci ◽  
Koel J. Brooks ◽  
Meghan M. Nelson ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Outcome Measures ◽  
Hip Joint ◽  
Repeated Measures ◽  
Muscle Activation ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Muscle Recruitment ◽  
Gluteus Medius Muscle ◽  
The Cross

Context:No published studies have compared muscle activation levels simultaneously for the gluteus maximus and medius muscles of stance and moving limbs during standing hip-joint strengthening while using elastic-tubing resistance.Objective:To quantify activation levels bilaterally of the gluteus maximus and medius during resisted lower-extremity standing exercises using elastic tubing for the cross-over, reverse cross-over, front-pull, and back-pull exercise conditions.Design:Repeated measures.Setting:Laboratory.Participants:26 active and healthy people, 13 men (25 ± 3 y) and 13 women (24 ± 1 y).Intervention:Subjects completed 3 consecutive repetitions of lower-extremity exercises in random order.Main Outcome Measures:Surface electromyographic (EMG) signals were normalized to peak activity in the maximum voluntary isometric contraction (MVIC) trial and expressed as a percentage. Magnitudes of EMG recruitment were analyzed with a 2 × 4 repeated-measures ANOVA for each muscle (α = .05).Results:For the gluteus maximus an interaction between exercise and limb factor was significant (F3,75 = 21.5; P < .001). The moving-limb gluteus maximus was activated more than the stance limb's during the back-pull exercise (P < .001), and moving-limb gluteus maximus muscle recruitment was greater for the back-pull exercise than for the cross-over, reverse cross-over, and front-pull exercises (P < .001). For the gluteus medius an interaction between exercise and limb factor was significant (F3,75 = 3.7; P < .03). Gluteus medius muscle recruitment (% MVIC) was greater in the stance limb than moving limb when performing the front-pull exercise (P < .001). Moving-limb gluteus medius muscle recruitment was greater for the reverse cross-over exercise than for the cross-over, front-pull, and back-pull exercises (P < .001).Conclusions:From a clinical standpoint there is no therapeutic benefit to selectively activate the gluteus maximus and gluteus medius muscles on the stance limb by resisting sagittal- and frontal-plane hip movements on the moving limb using resistance supplied by elastic tubing.

scholarly journals Continuous and Intermittent Artificial Gravity as a Countermeasure to the Cognitive Effects of 60 Days of Head-Down Tilt Bed Rest

2021 ◽  
Vol 12 ◽  
Author(s):  
Mathias Basner ◽  
David F. Dinges ◽  
Kia Howard ◽  
Tyler M. Moore ◽  
Ruben C. Gur ◽  
...  
Keyword(s):  
Emotion Recognition ◽  
Cognitive Performance ◽  
Recognition Performance ◽  
Center Of Mass ◽  
Bed Rest ◽  
Artificial Gravity ◽  
Control Group ◽  
Psychological Stressors ◽  
Positive Valence ◽  
Survey Responses

Environmental and psychological stressors can adversely affect astronaut cognitive performance in space. This study used a 6° head-down tilt bed rest (HDBR) paradigm to simulate some of the physiologic changes induced by microgravity. Twenty-four participants (mean ± SD age 33.3 ± 9.2 years, N = 16 men) spent 60 consecutive days in strict HDBR. They were studied in three groups of eight subjects each. One group served as Control, whereas the other two groups received either a continuous or intermittent artificial gravity (AG) countermeasure of 30 min centrifugation daily (1 g acceleration at the center of mass and 2 g at the feet). Participants performed all 10 tests of NASA’s Cognition battery and a brief alertness and mood survey repeatedly before, during, and after the HDBR period. Test scores were adjusted for practice and stimulus set difficulty effects. A modest but statistically significant slowing across a range of cognitive domains was found in all three groups during HDBR compared to baseline, most consistently for sensorimotor speed, whereas accuracy was unaffected. These changes were observed early during HDBR and did not further worsen or improve with increasing time in HDBR, except for emotion recognition performance. With increasing time spent in HDBR, participants required longer time to decide which facial emotion was expressed. They were also more likely to select categories with negative valence over categories with neutral or positive valence. Except for workload, which was rated lower in the Control group, continuous or intermittent AG did not modify the effect of HDBR on cognitive performance or subjective responses. Participants expressed several negative survey responses during HDBR relative to baseline, and some of the responses further deteriorated during recovery, which highlights the importance of adequate medical and psychological support during extended duration HDBR studies. In conclusion, 60 days of HDBR were associated with moderate cognitive slowing and changes in emotion recognition performance, but these effects were not mitigated by either continuous or intermittent exposure to AG for 30 min daily.

scholarly journals Muscle Activation During Landing Before and After Fatigue in Individuals With or Without Chronic Ankle Instability

2016 ◽  
Vol 51 (8) ◽  
pp. 629-636 ◽  
Author(s):  
Kathryn A. Webster ◽  
Brian G. Pietrosimone ◽  
Phillip A. Gribble
Keyword(s):  
Effect Size ◽  
Tibialis Anterior ◽  
Muscle Activation ◽  
Ankle Instability ◽  
Gluteus Maximus ◽  
Gluteus Medius ◽  
Control Group ◽  
Physically Active ◽  
Peroneus Longus ◽  
Before And After

Context: Ankle instability is a common condition in physically active individuals. It often occurs during a jump landing or lateral motion, particularly when participants are fatigued. Objective: To compare muscle activation during a lateral hop prefatigue and postfatigue in individuals with or without chronic ankle instability (CAI). Design: Cross-sectional study. Setting: Sports medicine research laboratory. Patients or Other Participants: A total of 32 physically active participants volunteered for the study. Sixteen participants with CAI (8 men, 8 women; age = 20.50 ± 2.00 years, height = 172.25 ± 10.87 cm, mass = 69.13 ± 13.31 kg) were matched with 16 control participants without CAI (8 men, 8 women; age = 22.00 ± 3.30 years, height = 170.50 ± 9.94 cm, mass = 69.63 ± 14.82 kg) by age, height, mass, sex, and affected side. Intervention(s): Electromyography of the tibialis anterior, peroneus longus, gluteus medius, and gluteus maximus was measured before and after a functional fatigue protocol. Main Outcome Measure(s): Activation of 4 lower extremity muscles was measured 200 milliseconds before and after landing from a lateral hop. Results: We observed no interactions. The group main effects for the peroneus longus demonstrated higher muscle activation in the CAI group (52.89% ± 11.36%) than in the control group (41.12% ± 11.36%) just before landing the lateral hop (F1,30 = 8.58, P = .01), with a strong effect size (d = 1.01). The gluteus maximus also demonstrated higher muscle activation in the CAI group (45.55% ± 12.08%) than in the control group (36.81% ± 12.08%) just before landing the lateral hop (F1,30 = 4.19, P = .049), with a moderate effect size (d = 0.71). We observed a main effect for fatigue for the tibialis anterior, with postfatigue activation higher than prefatigue activation (F1,30 = 7.45, P = .01). No differences were present between groups for the gluteus medius. Conclusions: Our results support the presence of a centralized feed-forward neuromuscular alteration in patients with CAI, not only in the ankle-joint muscles but also in the proximal hip muscles. These results may have implications for rehabilitation programs in these patients.

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